drivers/mtd/nand/omap2.c

   1 /*
   2  * Copyright © 2004 Texas Instruments, Jian Zhang <[email protected]>
   3  * Copyright © 2004 Micron Technology Inc.
   4  * Copyright © 2004 David Brownell
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/platform_device.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/dma-mapping.h>
  14 #include <linux/delay.h>
  15 #include <linux/gpio/consumer.h>
  16 #include <linux/module.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/sched.h>
  20 #include <linux/mtd/mtd.h>
  21 #include <linux/mtd/rawnand.h>
  22 #include <linux/mtd/partitions.h>
  23 #include <linux/omap-dma.h>
  24 #include <linux/io.h>
  25 #include <linux/slab.h>
  26 #include <linux/of.h>
  27 #include <linux/of_device.h>
  28
  29 #include <linux/mtd/nand_bch.h>
  30 #include <linux/platform_data/elm.h>
  31
  32 #include <linux/omap-gpmc.h>
  33 #include <linux/platform_data/mtd-nand-omap2.h>
  34
  35 #define DRIVER_NAME     "omap2-nand"
  36 #define OMAP_NAND_TIMEOUT_MS    5000
  37
  38 #define NAND_Ecc_P1e            (1 << 0)
  39 #define NAND_Ecc_P2e            (1 << 1)
  40 #define NAND_Ecc_P4e            (1 << 2)
  41 #define NAND_Ecc_P8e            (1 << 3)
  42 #define NAND_Ecc_P16e           (1 << 4)
  43 #define NAND_Ecc_P32e           (1 << 5)
  44 #define NAND_Ecc_P64e           (1 << 6)
  45 #define NAND_Ecc_P128e          (1 << 7)
  46 #define NAND_Ecc_P256e          (1 << 8)
  47 #define NAND_Ecc_P512e          (1 << 9)
  48 #define NAND_Ecc_P1024e         (1 << 10)
  49 #define NAND_Ecc_P2048e         (1 << 11)
  50
  51 #define NAND_Ecc_P1o            (1 << 16)
  52 #define NAND_Ecc_P2o            (1 << 17)
  53 #define NAND_Ecc_P4o            (1 << 18)
  54 #define NAND_Ecc_P8o            (1 << 19)
  55 #define NAND_Ecc_P16o           (1 << 20)
  56 #define NAND_Ecc_P32o           (1 << 21)
  57 #define NAND_Ecc_P64o           (1 << 22)
  58 #define NAND_Ecc_P128o          (1 << 23)
  59 #define NAND_Ecc_P256o          (1 << 24)
  60 #define NAND_Ecc_P512o          (1 << 25)
  61 #define NAND_Ecc_P1024o         (1 << 26)
  62 #define NAND_Ecc_P2048o         (1 << 27)
  63
  64 #define TF(value)       (value ? 1 : 0)
  65
  66 #define P2048e(a)       (TF(a & NAND_Ecc_P2048e)        << 0)
  67 #define P2048o(a)       (TF(a & NAND_Ecc_P2048o)        << 1)
  68 #define P1e(a)          (TF(a & NAND_Ecc_P1e)           << 2)
  69 #define P1o(a)          (TF(a & NAND_Ecc_P1o)           << 3)
  70 #define P2e(a)          (TF(a & NAND_Ecc_P2e)           << 4)
  71 #define P2o(a)          (TF(a & NAND_Ecc_P2o)           << 5)
  72 #define P4e(a)          (TF(a & NAND_Ecc_P4e)           << 6)
  73 #define P4o(a)          (TF(a & NAND_Ecc_P4o)           << 7)
  74
  75 #define P8e(a)          (TF(a & NAND_Ecc_P8e)           << 0)
  76 #define P8o(a)          (TF(a & NAND_Ecc_P8o)           << 1)
  77 #define P16e(a)         (TF(a & NAND_Ecc_P16e)          << 2)
  78 #define P16o(a)         (TF(a & NAND_Ecc_P16o)          << 3)
  79 #define P32e(a)         (TF(a & NAND_Ecc_P32e)          << 4)
  80 #define P32o(a)         (TF(a & NAND_Ecc_P32o)          << 5)
  81 #define P64e(a)         (TF(a & NAND_Ecc_P64e)          << 6)
  82 #define P64o(a)         (TF(a & NAND_Ecc_P64o)          << 7)
  83
  84 #define P128e(a)        (TF(a & NAND_Ecc_P128e)         << 0)
  85 #define P128o(a)        (TF(a & NAND_Ecc_P128o)         << 1)
  86 #define P256e(a)        (TF(a & NAND_Ecc_P256e)         << 2)
  87 #define P256o(a)        (TF(a & NAND_Ecc_P256o)         << 3)
  88 #define P512e(a)        (TF(a & NAND_Ecc_P512e)         << 4)
  89 #define P512o(a)        (TF(a & NAND_Ecc_P512o)         << 5)
  90 #define P1024e(a)       (TF(a & NAND_Ecc_P1024e)        << 6)
  91 #define P1024o(a)       (TF(a & NAND_Ecc_P1024o)        << 7)
  92
  93 #define P8e_s(a)        (TF(a & NAND_Ecc_P8e)           << 0)
  94 #define P8o_s(a)        (TF(a & NAND_Ecc_P8o)           << 1)
  95 #define P16e_s(a)       (TF(a & NAND_Ecc_P16e)          << 2)
  96 #define P16o_s(a)       (TF(a & NAND_Ecc_P16o)          << 3)
  97 #define P1e_s(a)        (TF(a & NAND_Ecc_P1e)           << 4)
  98 #define P1o_s(a)        (TF(a & NAND_Ecc_P1o)           << 5)
  99 #define P2e_s(a)        (TF(a & NAND_Ecc_P2e)           << 6)
 100 #define P2o_s(a)        (TF(a & NAND_Ecc_P2o)           << 7)
 101
 102 #define P4e_s(a)        (TF(a & NAND_Ecc_P4e)           << 0)
 103 #define P4o_s(a)        (TF(a & NAND_Ecc_P4o)           << 1)
 104
 105 #define PREFETCH_CONFIG1_CS_SHIFT       24
 106 #define ECC_CONFIG_CS_SHIFT             1
 107 #define CS_MASK                         0x7
 108 #define ENABLE_PREFETCH                 (0x1 << 7)
 109 #define DMA_MPU_MODE_SHIFT              2
 110 #define ECCSIZE0_SHIFT                  12
 111 #define ECCSIZE1_SHIFT                  22
 112 #define ECC1RESULTSIZE                  0x1
 113 #define ECCCLEAR                        0x100
 114 #define ECC1                            0x1
 115 #define PREFETCH_FIFOTHRESHOLD_MAX      0x40
 116 #define PREFETCH_FIFOTHRESHOLD(val)     ((val) << 8)
 117 #define PREFETCH_STATUS_COUNT(val)      (val & 0x00003fff)
 118 #define PREFETCH_STATUS_FIFO_CNT(val)   ((val >> 24) & 0x7F)
 119 #define STATUS_BUFF_EMPTY               0x00000001
 120
 121 #define SECTOR_BYTES            512
 122 /* 4 bit padding to make byte aligned, 56 = 52 + 4 */
 123 #define BCH4_BIT_PAD            4
 124
 125 /* GPMC ecc engine settings for read */
 126 #define BCH_WRAPMODE_1          1       /* BCH wrap mode 1 */
 127 #define BCH8R_ECC_SIZE0         0x1a    /* ecc_size0 = 26 */
 128 #define BCH8R_ECC_SIZE1         0x2     /* ecc_size1 = 2 */
 129 #define BCH4R_ECC_SIZE0         0xd     /* ecc_size0 = 13 */
 130 #define BCH4R_ECC_SIZE1         0x3     /* ecc_size1 = 3 */
 131
 132 /* GPMC ecc engine settings for write */
 133 #define BCH_WRAPMODE_6          6       /* BCH wrap mode 6 */
 134 #define BCH_ECC_SIZE0           0x0     /* ecc_size0 = 0, no oob protection */
 135 #define BCH_ECC_SIZE1           0x20    /* ecc_size1 = 32 */
 136
 137 #define BADBLOCK_MARKER_LENGTH          2
 138
 139 static u_char bch16_vector[] = {0xf5, 0x24, 0x1c, 0xd0, 0x61, 0xb3, 0xf1, 0x55,
 140                                 0x2e, 0x2c, 0x86, 0xa3, 0xed, 0x36, 0x1b, 0x78,
 141                                 0x48, 0x76, 0xa9, 0x3b, 0x97, 0xd1, 0x7a, 0x93,
 142                                 0x07, 0x0e};
 143 static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc,
 144         0xac, 0x6b, 0xff, 0x99, 0x7b};
 145 static u_char bch4_vector[] = {0x00, 0x6b, 0x31, 0xdd, 0x41, 0xbc, 0x10};
 146
 147 /* Shared among all NAND instances to synchronize access to the ECC Engine */
 148 static struct nand_hw_control omap_gpmc_controller = {
 149         .lock = __SPIN_LOCK_UNLOCKED(omap_gpmc_controller.lock),
 150         .wq = __WAIT_QUEUE_HEAD_INITIALIZER(omap_gpmc_controller.wq),
 151 };
 152
 153 struct omap_nand_info {
 154         struct nand_chip                nand;
 155         struct platform_device          *pdev;
 156
 157         int                             gpmc_cs;
 158         bool                            dev_ready;
 159         enum nand_io                    xfer_type;
 160         int                             devsize;
 161         enum omap_ecc                   ecc_opt;
 162         struct device_node              *elm_of_node;
 163
 164         unsigned long                   phys_base;
 165         struct completion               comp;
 166         struct dma_chan                 *dma;
 167         int                             gpmc_irq_fifo;
 168         int                             gpmc_irq_count;
 169         enum {
 170                 OMAP_NAND_IO_READ = 0,  /* read */
 171                 OMAP_NAND_IO_WRITE,     /* write */
 172         } iomode;
 173         u_char                          *buf;
 174         int                                     buf_len;
 175         /* Interface to GPMC */
 176         struct gpmc_nand_regs           reg;
 177         struct gpmc_nand_ops            *ops;
 178         bool                            flash_bbt;
 179         /* fields specific for BCHx_HW ECC scheme */
 180         struct device                   *elm_dev;
 181         /* NAND ready gpio */
 182         struct gpio_desc                *ready_gpiod;
 183 };
 184
 185 static inline struct omap_nand_info *mtd_to_omap(struct mtd_info *mtd)
 186 {
 187         return container_of(mtd_to_nand(mtd), struct omap_nand_info, nand);
 188 }
 189
 190 /**
 191  * omap_prefetch_enable - configures and starts prefetch transfer
 192  * @cs: cs (chip select) number
 193  * @fifo_th: fifo threshold to be used for read/ write
 194  * @dma_mode: dma mode enable (1) or disable (0)
 195  * @u32_count: number of bytes to be transferred
 196  * @is_write: prefetch read(0) or write post(1) mode
 197  */
 198 static int omap_prefetch_enable(int cs, int fifo_th, int dma_mode,
 199         unsigned int u32_count, int is_write, struct omap_nand_info *info)
 200 {
 201         u32 val;
 202
 203         if (fifo_th > PREFETCH_FIFOTHRESHOLD_MAX)
 204                 return -1;
 205
 206         if (readl(info->reg.gpmc_prefetch_control))
 207                 return -EBUSY;
 208
 209         /* Set the amount of bytes to be prefetched */
 210         writel(u32_count, info->reg.gpmc_prefetch_config2);
 211
 212         /* Set dma/mpu mode, the prefetch read / post write and
 213          * enable the engine. Set which cs is has requested for.
 214          */
 215         val = ((cs << PREFETCH_CONFIG1_CS_SHIFT) |
 216                 PREFETCH_FIFOTHRESHOLD(fifo_th) | ENABLE_PREFETCH |
 217                 (dma_mode << DMA_MPU_MODE_SHIFT) | (is_write & 0x1));
 218         writel(val, info->reg.gpmc_prefetch_config1);
 219
 220         /*  Start the prefetch engine */
 221         writel(0x1, info->reg.gpmc_prefetch_control);
 222
 223         return 0;
 224 }
 225
 226 /**
 227  * omap_prefetch_reset - disables and stops the prefetch engine
 228  */
 229 static int omap_prefetch_reset(int cs, struct omap_nand_info *info)
 230 {
 231         u32 config1;
 232
 233         /* check if the same module/cs is trying to reset */
 234         config1 = readl(info->reg.gpmc_prefetch_config1);
 235         if (((config1 >> PREFETCH_CONFIG1_CS_SHIFT) & CS_MASK) != cs)
 236                 return -EINVAL;
 237
 238         /* Stop the PFPW engine */
 239         writel(0x0, info->reg.gpmc_prefetch_control);
 240
 241         /* Reset/disable the PFPW engine */
 242         writel(0x0, info->reg.gpmc_prefetch_config1);
 243
 244         return 0;
 245 }
 246
 247 /**
 248  * omap_hwcontrol - hardware specific access to control-lines
 249  * @mtd: MTD device structure
 250  * @cmd: command to device
 251  * @ctrl:
 252  * NAND_NCE: bit 0 -> don't care
 253  * NAND_CLE: bit 1 -> Command Latch
 254  * NAND_ALE: bit 2 -> Address Latch
 255  *
 256  * NOTE: boards may use different bits for these!!
 257  */
 258 static void omap_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 259 {
 260         struct omap_nand_info *info = mtd_to_omap(mtd);
 261
 262         if (cmd != NAND_CMD_NONE) {
 263                 if (ctrl & NAND_CLE)
 264                         writeb(cmd, info->reg.gpmc_nand_command);
 265
 266                 else if (ctrl & NAND_ALE)
 267                         writeb(cmd, info->reg.gpmc_nand_address);
 268
 269                 else /* NAND_NCE */
 270                         writeb(cmd, info->reg.gpmc_nand_data);
 271         }
 272 }
 273
 274 /**
 275  * omap_read_buf8 - read data from NAND controller into buffer
 276  * @mtd: MTD device structure
 277  * @buf: buffer to store date
 278  * @len: number of bytes to read
 279  */
 280 static void omap_read_buf8(struct mtd_info *mtd, u_char *buf, int len)
 281 {
 282         struct nand_chip *nand = mtd_to_nand(mtd);
 283
 284         ioread8_rep(nand->IO_ADDR_R, buf, len);
 285 }
 286
 287 /**
 288  * omap_write_buf8 - write buffer to NAND controller
 289  * @mtd: MTD device structure
 290  * @buf: data buffer
 291  * @len: number of bytes to write
 292  */
 293 static void omap_write_buf8(struct mtd_info *mtd, const u_char *buf, int len)
 294 {
 295         struct omap_nand_info *info = mtd_to_omap(mtd);
 296         u_char *p = (u_char *)buf;
 297         bool status;
 298
 299         while (len--) {
 300                 iowrite8(*p++, info->nand.IO_ADDR_W);
 301                 /* wait until buffer is available for write */
 302                 do {
 303                         status = info->ops->nand_writebuffer_empty();
 304                 } while (!status);
 305         }
 306 }
 307
 308 /**
 309  * omap_read_buf16 - read data from NAND controller into buffer
 310  * @mtd: MTD device structure
 311  * @buf: buffer to store date
 312  * @len: number of bytes to read
 313  */
 314 static void omap_read_buf16(struct mtd_info *mtd, u_char *buf, int len)
 315 {
 316         struct nand_chip *nand = mtd_to_nand(mtd);
 317
 318         ioread16_rep(nand->IO_ADDR_R, buf, len / 2);
 319 }
 320
 321 /**
 322  * omap_write_buf16 - write buffer to NAND controller
 323  * @mtd: MTD device structure
 324  * @buf: data buffer
 325  * @len: number of bytes to write
 326  */
 327 static void omap_write_buf16(struct mtd_info *mtd, const u_char * buf, int len)
 328 {
 329         struct omap_nand_info *info = mtd_to_omap(mtd);
 330         u16 *p = (u16 *) buf;
 331         bool status;
 332         /* FIXME try bursts of writesw() or DMA ... */
 333         len >>= 1;
 334
 335         while (len--) {
 336                 iowrite16(*p++, info->nand.IO_ADDR_W);
 337                 /* wait until buffer is available for write */
 338                 do {
 339                         status = info->ops->nand_writebuffer_empty();
 340                 } while (!status);
 341         }
 342 }
 343
 344 /**
 345  * omap_read_buf_pref - read data from NAND controller into buffer
 346  * @mtd: MTD device structure
 347  * @buf: buffer to store date
 348  * @len: number of bytes to read
 349  */
 350 static void omap_read_buf_pref(struct mtd_info *mtd, u_char *buf, int len)
 351 {
 352         struct omap_nand_info *info = mtd_to_omap(mtd);
 353         uint32_t r_count = 0;
 354         int ret = 0;
 355         u32 *p = (u32 *)buf;
 356
 357         /* take care of subpage reads */
 358         if (len % 4) {
 359                 if (info->nand.options & NAND_BUSWIDTH_16)
 360                         omap_read_buf16(mtd, buf, len % 4);
 361                 else
 362                         omap_read_buf8(mtd, buf, len % 4);
 363                 p = (u32 *) (buf + len % 4);
 364                 len -= len % 4;
 365         }
 366
 367         /* configure and start prefetch transfer */
 368         ret = omap_prefetch_enable(info->gpmc_cs,
 369                         PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x0, info);
 370         if (ret) {
 371                 /* PFPW engine is busy, use cpu copy method */
 372                 if (info->nand.options & NAND_BUSWIDTH_16)
 373                         omap_read_buf16(mtd, (u_char *)p, len);
 374                 else
 375                         omap_read_buf8(mtd, (u_char *)p, len);
 376         } else {
 377                 do {
 378                         r_count = readl(info->reg.gpmc_prefetch_status);
 379                         r_count = PREFETCH_STATUS_FIFO_CNT(r_count);
 380                         r_count = r_count >> 2;
 381                         ioread32_rep(info->nand.IO_ADDR_R, p, r_count);
 382                         p += r_count;
 383                         len -= r_count << 2;
 384                 } while (len);
 385                 /* disable and stop the PFPW engine */
 386                 omap_prefetch_reset(info->gpmc_cs, info);
 387         }
 388 }
 389
 390 /**
 391  * omap_write_buf_pref - write buffer to NAND controller
 392  * @mtd: MTD device structure
 393  * @buf: data buffer
 394  * @len: number of bytes to write
 395  */
 396 static void omap_write_buf_pref(struct mtd_info *mtd,
 397                                         const u_char *buf, int len)
 398 {
 399         struct omap_nand_info *info = mtd_to_omap(mtd);
 400         uint32_t w_count = 0;
 401         int i = 0, ret = 0;
 402         u16 *p = (u16 *)buf;
 403         unsigned long tim, limit;
 404         u32 val;
 405
 406         /* take care of subpage writes */
 407         if (len % 2 != 0) {
 408                 writeb(*buf, info->nand.IO_ADDR_W);
 409                 p = (u16 *)(buf + 1);
 410                 len--;
 411         }
 412
 413         /*  configure and start prefetch transfer */
 414         ret = omap_prefetch_enable(info->gpmc_cs,
 415                         PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x1, info);
 416         if (ret) {
 417                 /* PFPW engine is busy, use cpu copy method */
 418                 if (info->nand.options & NAND_BUSWIDTH_16)
 419                         omap_write_buf16(mtd, (u_char *)p, len);
 420                 else
 421                         omap_write_buf8(mtd, (u_char *)p, len);
 422         } else {
 423                 while (len) {
 424                         w_count = readl(info->reg.gpmc_prefetch_status);
 425                         w_count = PREFETCH_STATUS_FIFO_CNT(w_count);
 426                         w_count = w_count >> 1;
 427                         for (i = 0; (i < w_count) && len; i++, len -= 2)
 428                                 iowrite16(*p++, info->nand.IO_ADDR_W);
 429                 }
 430                 /* wait for data to flushed-out before reset the prefetch */
 431                 tim = 0;
 432                 limit = (loops_per_jiffy *
 433                                         msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
 434                 do {
 435                         cpu_relax();
 436                         val = readl(info->reg.gpmc_prefetch_status);
 437                         val = PREFETCH_STATUS_COUNT(val);
 438                 } while (val && (tim++ < limit));
 439
 440                 /* disable and stop the PFPW engine */
 441                 omap_prefetch_reset(info->gpmc_cs, info);
 442         }
 443 }
 444
 445 /*
 446  * omap_nand_dma_callback: callback on the completion of dma transfer
 447  * @data: pointer to completion data structure
 448  */
 449 static void omap_nand_dma_callback(void *data)
 450 {
 451         complete((struct completion *) data);
 452 }
 453
 454 /*
 455  * omap_nand_dma_transfer: configure and start dma transfer
 456  * @mtd: MTD device structure
 457  * @addr: virtual address in RAM of source/destination
 458  * @len: number of data bytes to be transferred
 459  * @is_write: flag for read/write operation
 460  */
 461 static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
 462                                         unsigned int len, int is_write)
 463 {
 464         struct omap_nand_info *info = mtd_to_omap(mtd);
 465         struct dma_async_tx_descriptor *tx;
 466         enum dma_data_direction dir = is_write ? DMA_TO_DEVICE :
 467                                                         DMA_FROM_DEVICE;
 468         struct scatterlist sg;
 469         unsigned long tim, limit;
 470         unsigned n;
 471         int ret;
 472         u32 val;
 473
 474         if (!virt_addr_valid(addr))
 475                 goto out_copy;
 476
 477         sg_init_one(&sg, addr, len);
 478         n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
 479         if (n == 0) {
 480                 dev_err(&info->pdev->dev,
 481                         "Couldn't DMA map a %d byte buffer\n", len);
 482                 goto out_copy;
 483         }
 484
 485         tx = dmaengine_prep_slave_sg(info->dma, &sg, n,
 486                 is_write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
 487                 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 488         if (!tx)
 489                 goto out_copy_unmap;
 490
 491         tx->callback = omap_nand_dma_callback;
 492         tx->callback_param = &info->comp;
 493         dmaengine_submit(tx);
 494
 495         init_completion(&info->comp);
 496
 497         /* setup and start DMA using dma_addr */
 498         dma_async_issue_pending(info->dma);
 499
 500         /*  configure and start prefetch transfer */
 501         ret = omap_prefetch_enable(info->gpmc_cs,
 502                 PREFETCH_FIFOTHRESHOLD_MAX, 0x1, len, is_write, info);
 503         if (ret)
 504                 /* PFPW engine is busy, use cpu copy method */
 505                 goto out_copy_unmap;
 506
 507         wait_for_completion(&info->comp);
 508         tim = 0;
 509         limit = (loops_per_jiffy * msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
 510
 511         do {
 512                 cpu_relax();
 513                 val = readl(info->reg.gpmc_prefetch_status);
 514                 val = PREFETCH_STATUS_COUNT(val);
 515         } while (val && (tim++ < limit));
 516
 517         /* disable and stop the PFPW engine */
 518         omap_prefetch_reset(info->gpmc_cs, info);
 519
 520         dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
 521         return 0;
 522
 523 out_copy_unmap:
 524         dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
 525 out_copy:
 526         if (info->nand.options & NAND_BUSWIDTH_16)
 527                 is_write == 0 ? omap_read_buf16(mtd, (u_char *) addr, len)
 528                         : omap_write_buf16(mtd, (u_char *) addr, len);
 529         else
 530                 is_write == 0 ? omap_read_buf8(mtd, (u_char *) addr, len)
 531                         : omap_write_buf8(mtd, (u_char *) addr, len);
 532         return 0;
 533 }
 534
 535 /**
 536  * omap_read_buf_dma_pref - read data from NAND controller into buffer
 537  * @mtd: MTD device structure
 538  * @buf: buffer to store date
 539  * @len: number of bytes to read
 540  */
 541 static void omap_read_buf_dma_pref(struct mtd_info *mtd, u_char *buf, int len)
 542 {
 543         if (len <= mtd->oobsize)
 544                 omap_read_buf_pref(mtd, buf, len);
 545         else
 546                 /* start transfer in DMA mode */
 547                 omap_nand_dma_transfer(mtd, buf, len, 0x0);
 548 }
 549
 550 /**
 551  * omap_write_buf_dma_pref - write buffer to NAND controller
 552  * @mtd: MTD device structure
 553  * @buf: data buffer
 554  * @len: number of bytes to write
 555  */
 556 static void omap_write_buf_dma_pref(struct mtd_info *mtd,
 557                                         const u_char *buf, int len)
 558 {
 559         if (len <= mtd->oobsize)
 560                 omap_write_buf_pref(mtd, buf, len);
 561         else
 562                 /* start transfer in DMA mode */
 563                 omap_nand_dma_transfer(mtd, (u_char *) buf, len, 0x1);
 564 }
 565
 566 /*
 567  * omap_nand_irq - GPMC irq handler
 568  * @this_irq: gpmc irq number
 569  * @dev: omap_nand_info structure pointer is passed here
 570  */
 571 static irqreturn_t omap_nand_irq(int this_irq, void *dev)
 572 {
 573         struct omap_nand_info *info = (struct omap_nand_info *) dev;
 574         u32 bytes;
 575
 576         bytes = readl(info->reg.gpmc_prefetch_status);
 577         bytes = PREFETCH_STATUS_FIFO_CNT(bytes);
 578         bytes = bytes  & 0xFFFC; /* io in multiple of 4 bytes */
 579         if (info->iomode == OMAP_NAND_IO_WRITE) { /* checks for write io */
 580                 if (this_irq == info->gpmc_irq_count)
 581                         goto done;
 582
 583                 if (info->buf_len && (info->buf_len < bytes))
 584                         bytes = info->buf_len;
 585                 else if (!info->buf_len)
 586                         bytes = 0;
 587                 iowrite32_rep(info->nand.IO_ADDR_W,
 588                                                 (u32 *)info->buf, bytes >> 2);
 589                 info->buf = info->buf + bytes;
 590                 info->buf_len -= bytes;
 591
 592         } else {
 593                 ioread32_rep(info->nand.IO_ADDR_R,
 594                                                 (u32 *)info->buf, bytes >> 2);
 595                 info->buf = info->buf + bytes;
 596
 597                 if (this_irq == info->gpmc_irq_count)
 598                         goto done;
 599         }
 600
 601         return IRQ_HANDLED;
 602
 603 done:
 604         complete(&info->comp);
 605
 606         disable_irq_nosync(info->gpmc_irq_fifo);
 607         disable_irq_nosync(info->gpmc_irq_count);
 608
 609         return IRQ_HANDLED;
 610 }
 611
 612 /*
 613  * omap_read_buf_irq_pref - read data from NAND controller into buffer
 614  * @mtd: MTD device structure
 615  * @buf: buffer to store date
 616  * @len: number of bytes to read
 617  */
 618 static void omap_read_buf_irq_pref(struct mtd_info *mtd, u_char *buf, int len)
 619 {
 620         struct omap_nand_info *info = mtd_to_omap(mtd);
 621         int ret = 0;
 622
 623         if (len <= mtd->oobsize) {
 624                 omap_read_buf_pref(mtd, buf, len);
 625                 return;
 626         }
 627
 628         info->iomode = OMAP_NAND_IO_READ;
 629         info->buf = buf;
 630         init_completion(&info->comp);
 631
 632         /*  configure and start prefetch transfer */
 633         ret = omap_prefetch_enable(info->gpmc_cs,
 634                         PREFETCH_FIFOTHRESHOLD_MAX/2, 0x0, len, 0x0, info);
 635         if (ret)
 636                 /* PFPW engine is busy, use cpu copy method */
 637                 goto out_copy;
 638
 639         info->buf_len = len;
 640
 641         enable_irq(info->gpmc_irq_count);
 642         enable_irq(info->gpmc_irq_fifo);
 643
 644         /* waiting for read to complete */
 645         wait_for_completion(&info->comp);
 646
 647         /* disable and stop the PFPW engine */
 648         omap_prefetch_reset(info->gpmc_cs, info);
 649         return;
 650
 651 out_copy:
 652         if (info->nand.options & NAND_BUSWIDTH_16)
 653                 omap_read_buf16(mtd, buf, len);
 654         else
 655                 omap_read_buf8(mtd, buf, len);
 656 }
 657
 658 /*
 659  * omap_write_buf_irq_pref - write buffer to NAND controller
 660  * @mtd: MTD device structure
 661  * @buf: data buffer
 662  * @len: number of bytes to write
 663  */
 664 static void omap_write_buf_irq_pref(struct mtd_info *mtd,
 665                                         const u_char *buf, int len)
 666 {
 667         struct omap_nand_info *info = mtd_to_omap(mtd);
 668         int ret = 0;
 669         unsigned long tim, limit;
 670         u32 val;
 671
 672         if (len <= mtd->oobsize) {
 673                 omap_write_buf_pref(mtd, buf, len);
 674                 return;
 675         }
 676
 677         info->iomode = OMAP_NAND_IO_WRITE;
 678         info->buf = (u_char *) buf;
 679         init_completion(&info->comp);
 680
 681         /* configure and start prefetch transfer : size=24 */
 682         ret = omap_prefetch_enable(info->gpmc_cs,
 683                 (PREFETCH_FIFOTHRESHOLD_MAX * 3) / 8, 0x0, len, 0x1, info);
 684         if (ret)
 685                 /* PFPW engine is busy, use cpu copy method */
 686                 goto out_copy;
 687
 688         info->buf_len = len;
 689
 690         enable_irq(info->gpmc_irq_count);
 691         enable_irq(info->gpmc_irq_fifo);
 692
 693         /* waiting for write to complete */
 694         wait_for_completion(&info->comp);
 695
 696         /* wait for data to flushed-out before reset the prefetch */
 697         tim = 0;
 698         limit = (loops_per_jiffy *  msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
 699         do {
 700                 val = readl(info->reg.gpmc_prefetch_status);
 701                 val = PREFETCH_STATUS_COUNT(val);
 702                 cpu_relax();
 703         } while (val && (tim++ < limit));
 704
 705         /* disable and stop the PFPW engine */
 706         omap_prefetch_reset(info->gpmc_cs, info);
 707         return;
 708
 709 out_copy:
 710         if (info->nand.options & NAND_BUSWIDTH_16)
 711                 omap_write_buf16(mtd, buf, len);
 712         else
 713                 omap_write_buf8(mtd, buf, len);
 714 }
 715
 716 /**
 717  * gen_true_ecc - This function will generate true ECC value
 718  * @ecc_buf: buffer to store ecc code
 719  *
 720  * This generated true ECC value can be used when correcting
 721  * data read from NAND flash memory core
 722  */
 723 static void gen_true_ecc(u8 *ecc_buf)
 724 {
 725         u32 tmp = ecc_buf[0] | (ecc_buf[1] << 16) |
 726                 ((ecc_buf[2] & 0xF0) << 20) | ((ecc_buf[2] & 0x0F) << 8);
 727
 728         ecc_buf[0] = ~(P64o(tmp) | P64e(tmp) | P32o(tmp) | P32e(tmp) |
 729                         P16o(tmp) | P16e(tmp) | P8o(tmp) | P8e(tmp));
 730         ecc_buf[1] = ~(P1024o(tmp) | P1024e(tmp) | P512o(tmp) | P512e(tmp) |
 731                         P256o(tmp) | P256e(tmp) | P128o(tmp) | P128e(tmp));
 732         ecc_buf[2] = ~(P4o(tmp) | P4e(tmp) | P2o(tmp) | P2e(tmp) | P1o(tmp) |
 733                         P1e(tmp) | P2048o(tmp) | P2048e(tmp));
 734 }
 735
 736 /**
 737  * omap_compare_ecc - Detect (2 bits) and correct (1 bit) error in data
 738  * @ecc_data1:  ecc code from nand spare area
 739  * @ecc_data2:  ecc code from hardware register obtained from hardware ecc
 740  * @page_data:  page data
 741  *
 742  * This function compares two ECC's and indicates if there is an error.
 743  * If the error can be corrected it will be corrected to the buffer.
 744  * If there is no error, %0 is returned. If there is an error but it
 745  * was corrected, %1 is returned. Otherwise, %-1 is returned.
 746  */
 747 static int omap_compare_ecc(u8 *ecc_data1,      /* read from NAND memory */
 748                             u8 *ecc_data2,      /* read from register */
 749                             u8 *page_data)
 750 {
 751         uint    i;
 752         u8      tmp0_bit[8], tmp1_bit[8], tmp2_bit[8];
 753         u8      comp0_bit[8], comp1_bit[8], comp2_bit[8];
 754         u8      ecc_bit[24];
 755         u8      ecc_sum = 0;
 756         u8      find_bit = 0;
 757         uint    find_byte = 0;
 758         int     isEccFF;
 759
 760         isEccFF = ((*(u32 *)ecc_data1 & 0xFFFFFF) == 0xFFFFFF);
 761
 762         gen_true_ecc(ecc_data1);
 763         gen_true_ecc(ecc_data2);
 764
 765         for (i = 0; i <= 2; i++) {
 766                 *(ecc_data1 + i) = ~(*(ecc_data1 + i));
 767                 *(ecc_data2 + i) = ~(*(ecc_data2 + i));
 768         }
 769
 770         for (i = 0; i < 8; i++) {
 771                 tmp0_bit[i]     = *ecc_data1 % 2;
 772                 *ecc_data1      = *ecc_data1 / 2;
 773         }
 774
 775         for (i = 0; i < 8; i++) {
 776                 tmp1_bit[i]      = *(ecc_data1 + 1) % 2;
 777                 *(ecc_data1 + 1) = *(ecc_data1 + 1) / 2;
 778         }
 779
 780         for (i = 0; i < 8; i++) {
 781                 tmp2_bit[i]      = *(ecc_data1 + 2) % 2;
 782                 *(ecc_data1 + 2) = *(ecc_data1 + 2) / 2;
 783         }
 784
 785         for (i = 0; i < 8; i++) {
 786                 comp0_bit[i]     = *ecc_data2 % 2;
 787                 *ecc_data2       = *ecc_data2 / 2;
 788         }
 789
 790         for (i = 0; i < 8; i++) {
 791                 comp1_bit[i]     = *(ecc_data2 + 1) % 2;
 792                 *(ecc_data2 + 1) = *(ecc_data2 + 1) / 2;
 793         }
 794
 795         for (i = 0; i < 8; i++) {
 796                 comp2_bit[i]     = *(ecc_data2 + 2) % 2;
 797                 *(ecc_data2 + 2) = *(ecc_data2 + 2) / 2;
 798         }
 799
 800         for (i = 0; i < 6; i++)
 801                 ecc_bit[i] = tmp2_bit[i + 2] ^ comp2_bit[i + 2];
 802
 803         for (i = 0; i < 8; i++)
 804                 ecc_bit[i + 6] = tmp0_bit[i] ^ comp0_bit[i];
 805
 806         for (i = 0; i < 8; i++)
 807                 ecc_bit[i + 14] = tmp1_bit[i] ^ comp1_bit[i];
 808
 809         ecc_bit[22] = tmp2_bit[0] ^ comp2_bit[0];
 810         ecc_bit[23] = tmp2_bit[1] ^ comp2_bit[1];
 811
 812         for (i = 0; i < 24; i++)
 813                 ecc_sum += ecc_bit[i];
 814
 815         switch (ecc_sum) {
 816         case 0:
 817                 /* Not reached because this function is not called if
 818                  *  ECC values are equal
 819                  */
 820                 return 0;
 821
 822         case 1:
 823                 /* Uncorrectable error */
 824                 pr_debug("ECC UNCORRECTED_ERROR 1\n");
 825                 return -EBADMSG;
 826
 827         case 11:
 828                 /* UN-Correctable error */
 829                 pr_debug("ECC UNCORRECTED_ERROR B\n");
 830                 return -EBADMSG;
 831
 832         case 12:
 833                 /* Correctable error */
 834                 find_byte = (ecc_bit[23] << 8) +
 835                             (ecc_bit[21] << 7) +
 836                             (ecc_bit[19] << 6) +
 837                             (ecc_bit[17] << 5) +
 838                             (ecc_bit[15] << 4) +
 839                             (ecc_bit[13] << 3) +
 840                             (ecc_bit[11] << 2) +
 841                             (ecc_bit[9]  << 1) +
 842                             ecc_bit[7];
 843
 844                 find_bit = (ecc_bit[5] << 2) + (ecc_bit[3] << 1) + ecc_bit[1];
 845
 846                 pr_debug("Correcting single bit ECC error at offset: "
 847                                 "%d, bit: %d\n", find_byte, find_bit);
 848
 849                 page_data[find_byte] ^= (1 << find_bit);
 850
 851                 return 1;
 852         default:
 853                 if (isEccFF) {
 854                         if (ecc_data2[0] == 0 &&
 855                             ecc_data2[1] == 0 &&
 856                             ecc_data2[2] == 0)
 857                                 return 0;
 858                 }
 859                 pr_debug("UNCORRECTED_ERROR default\n");
 860                 return -EBADMSG;
 861         }
 862 }
 863
 864 /**
 865  * omap_correct_data - Compares the ECC read with HW generated ECC
 866  * @mtd: MTD device structure
 867  * @dat: page data
 868  * @read_ecc: ecc read from nand flash
 869  * @calc_ecc: ecc read from HW ECC registers
 870  *
 871  * Compares the ecc read from nand spare area with ECC registers values
 872  * and if ECC's mismatched, it will call 'omap_compare_ecc' for error
 873  * detection and correction. If there are no errors, %0 is returned. If
 874  * there were errors and all of the errors were corrected, the number of
 875  * corrected errors is returned. If uncorrectable errors exist, %-1 is
 876  * returned.
 877  */
 878 static int omap_correct_data(struct mtd_info *mtd, u_char *dat,
 879                                 u_char *read_ecc, u_char *calc_ecc)
 880 {
 881         struct omap_nand_info *info = mtd_to_omap(mtd);
 882         int blockCnt = 0, i = 0, ret = 0;
 883         int stat = 0;
 884
 885         /* Ex NAND_ECC_HW12_2048 */
 886         if ((info->nand.ecc.mode == NAND_ECC_HW) &&
 887                         (info->nand.ecc.size  == 2048))
 888                 blockCnt = 4;
 889         else
 890                 blockCnt = 1;
 891
 892         for (i = 0; i < blockCnt; i++) {
 893                 if (memcmp(read_ecc, calc_ecc, 3) != 0) {
 894                         ret = omap_compare_ecc(read_ecc, calc_ecc, dat);
 895                         if (ret < 0)
 896                                 return ret;
 897                         /* keep track of the number of corrected errors */
 898                         stat += ret;
 899                 }
 900                 read_ecc += 3;
 901                 calc_ecc += 3;
 902                 dat      += 512;
 903         }
 904         return stat;
 905 }
 906
 907 /**
 908  * omap_calcuate_ecc - Generate non-inverted ECC bytes.
 909  * @mtd: MTD device structure
 910  * @dat: The pointer to data on which ecc is computed
 911  * @ecc_code: The ecc_code buffer
 912  *
 913  * Using noninverted ECC can be considered ugly since writing a blank
 914  * page ie. padding will clear the ECC bytes. This is no problem as long
 915  * nobody is trying to write data on the seemingly unused page. Reading
 916  * an erased page will produce an ECC mismatch between generated and read
 917  * ECC bytes that has to be dealt with separately.
 918  */
 919 static int omap_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
 920                                 u_char *ecc_code)
 921 {
 922         struct omap_nand_info *info = mtd_to_omap(mtd);
 923         u32 val;
 924
 925         val = readl(info->reg.gpmc_ecc_config);
 926         if (((val >> ECC_CONFIG_CS_SHIFT) & CS_MASK) != info->gpmc_cs)
 927                 return -EINVAL;
 928
 929         /* read ecc result */
 930         val = readl(info->reg.gpmc_ecc1_result);
 931         *ecc_code++ = val;          /* P128e, ..., P1e */
 932         *ecc_code++ = val >> 16;    /* P128o, ..., P1o */
 933         /* P2048o, P1024o, P512o, P256o, P2048e, P1024e, P512e, P256e */
 934         *ecc_code++ = ((val >> 8) & 0x0f) | ((val >> 20) & 0xf0);
 935
 936         return 0;
 937 }
 938
 939 /**
 940  * omap_enable_hwecc - This function enables the hardware ecc functionality
 941  * @mtd: MTD device structure
 942  * @mode: Read/Write mode
 943  */
 944 static void omap_enable_hwecc(struct mtd_info *mtd, int mode)
 945 {
 946         struct omap_nand_info *info = mtd_to_omap(mtd);
 947         struct nand_chip *chip = mtd_to_nand(mtd);
 948         unsigned int dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
 949         u32 val;
 950
 951         /* clear ecc and enable bits */
 952         val = ECCCLEAR | ECC1;
 953         writel(val, info->reg.gpmc_ecc_control);
 954
 955         /* program ecc and result sizes */
 956         val = ((((info->nand.ecc.size >> 1) - 1) << ECCSIZE1_SHIFT) |
 957                          ECC1RESULTSIZE);
 958         writel(val, info->reg.gpmc_ecc_size_config);
 959
 960         switch (mode) {
 961         case NAND_ECC_READ:
 962         case NAND_ECC_WRITE:
 963                 writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
 964                 break;
 965         case NAND_ECC_READSYN:
 966                 writel(ECCCLEAR, info->reg.gpmc_ecc_control);
 967                 break;
 968         default:
 969                 dev_info(&info->pdev->dev,
 970                         "error: unrecognized Mode[%d]!\n", mode);
 971                 break;
 972         }
 973
 974         /* (ECC 16 or 8 bit col) | ( CS  )  | ECC Enable */
 975         val = (dev_width << 7) | (info->gpmc_cs << 1) | (0x1);
 976         writel(val, info->reg.gpmc_ecc_config);
 977 }
 978
 979 /**
 980  * omap_wait - wait until the command is done
 981  * @mtd: MTD device structure
 982  * @chip: NAND Chip structure
 983  *
 984  * Wait function is called during Program and erase operations and
 985  * the way it is called from MTD layer, we should wait till the NAND
 986  * chip is ready after the programming/erase operation has completed.
 987  *
 988  * Erase can take up to 400ms and program up to 20ms according to
 989  * general NAND and SmartMedia specs
 990  */
 991 static int omap_wait(struct mtd_info *mtd, struct nand_chip *chip)
 992 {
 993         struct nand_chip *this = mtd_to_nand(mtd);
 994         struct omap_nand_info *info = mtd_to_omap(mtd);
 995         unsigned long timeo = jiffies;
 996         int status, state = this->state;
 997
 998         if (state == FL_ERASING)
 999                 timeo += msecs_to_jiffies(400);
1000         else
1001                 timeo += msecs_to_jiffies(20);
1002
1003         writeb(NAND_CMD_STATUS & 0xFF, info->reg.gpmc_nand_command);
1004         while (time_before(jiffies, timeo)) {
1005                 status = readb(info->reg.gpmc_nand_data);
1006                 if (status & NAND_STATUS_READY)
1007                         break;
1008                 cond_resched();
1009         }
1010
1011         status = readb(info->reg.gpmc_nand_data);
1012         return status;
1013 }
1014
1015 /**
1016  * omap_dev_ready - checks the NAND Ready GPIO line
1017  * @mtd: MTD device structure
1018  *
1019  * Returns true if ready and false if busy.
1020  */
1021 static int omap_dev_ready(struct mtd_info *mtd)
1022 {
1023         struct omap_nand_info *info = mtd_to_omap(mtd);
1024
1025         return gpiod_get_value(info->ready_gpiod);
1026 }
1027
1028 /**
1029  * omap_enable_hwecc_bch - Program GPMC to perform BCH ECC calculation
1030  * @mtd: MTD device structure
1031  * @mode: Read/Write mode
1032  *
1033  * When using BCH with SW correction (i.e. no ELM), sector size is set
1034  * to 512 bytes and we use BCH_WRAPMODE_6 wrapping mode
1035  * for both reading and writing with:
1036  * eccsize0 = 0  (no additional protected byte in spare area)
1037  * eccsize1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
1038  */
1039 static void __maybe_unused omap_enable_hwecc_bch(struct mtd_info *mtd, int mode)
1040 {
1041         unsigned int bch_type;
1042         unsigned int dev_width, nsectors;
1043         struct omap_nand_info *info = mtd_to_omap(mtd);
1044         enum omap_ecc ecc_opt = info->ecc_opt;
1045         struct nand_chip *chip = mtd_to_nand(mtd);
1046         u32 val, wr_mode;
1047         unsigned int ecc_size1, ecc_size0;
1048
1049         /* GPMC configurations for calculating ECC */
1050         switch (ecc_opt) {
1051         case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1052                 bch_type = 0;
1053                 nsectors = 1;
1054                 wr_mode   = BCH_WRAPMODE_6;
1055                 ecc_size0 = BCH_ECC_SIZE0;
1056                 ecc_size1 = BCH_ECC_SIZE1;
1057                 break;
1058         case OMAP_ECC_BCH4_CODE_HW:
1059                 bch_type = 0;
1060                 nsectors = chip->ecc.steps;
1061                 if (mode == NAND_ECC_READ) {
1062                         wr_mode   = BCH_WRAPMODE_1;
1063                         ecc_size0 = BCH4R_ECC_SIZE0;
1064                         ecc_size1 = BCH4R_ECC_SIZE1;
1065                 } else {
1066                         wr_mode   = BCH_WRAPMODE_6;
1067                         ecc_size0 = BCH_ECC_SIZE0;
1068                         ecc_size1 = BCH_ECC_SIZE1;
1069                 }
1070                 break;
1071         case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1072                 bch_type = 1;
1073                 nsectors = 1;
1074                 wr_mode   = BCH_WRAPMODE_6;
1075                 ecc_size0 = BCH_ECC_SIZE0;
1076                 ecc_size1 = BCH_ECC_SIZE1;
1077                 break;
1078         case OMAP_ECC_BCH8_CODE_HW:
1079                 bch_type = 1;
1080                 nsectors = chip->ecc.steps;
1081                 if (mode == NAND_ECC_READ) {
1082                         wr_mode   = BCH_WRAPMODE_1;
1083                         ecc_size0 = BCH8R_ECC_SIZE0;
1084                         ecc_size1 = BCH8R_ECC_SIZE1;
1085                 } else {
1086                         wr_mode   = BCH_WRAPMODE_6;
1087                         ecc_size0 = BCH_ECC_SIZE0;
1088                         ecc_size1 = BCH_ECC_SIZE1;
1089                 }
1090                 break;
1091         case OMAP_ECC_BCH16_CODE_HW:
1092                 bch_type = 0x2;
1093                 nsectors = chip->ecc.steps;
1094                 if (mode == NAND_ECC_READ) {
1095                         wr_mode   = 0x01;
1096                         ecc_size0 = 52; /* ECC bits in nibbles per sector */
1097                         ecc_size1 = 0;  /* non-ECC bits in nibbles per sector */
1098                 } else {
1099                         wr_mode   = 0x01;
1100                         ecc_size0 = 0;  /* extra bits in nibbles per sector */
1101                         ecc_size1 = 52; /* OOB bits in nibbles per sector */
1102                 }
1103                 break;
1104         default:
1105                 return;
1106         }
1107
1108         writel(ECC1, info->reg.gpmc_ecc_control);
1109
1110         /* Configure ecc size for BCH */
1111         val = (ecc_size1 << ECCSIZE1_SHIFT) | (ecc_size0 << ECCSIZE0_SHIFT);
1112         writel(val, info->reg.gpmc_ecc_size_config);
1113
1114         dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
1115
1116         /* BCH configuration */
1117         val = ((1                        << 16) | /* enable BCH */
1118                (bch_type                 << 12) | /* BCH4/BCH8/BCH16 */
1119                (wr_mode                  <<  8) | /* wrap mode */
1120                (dev_width                <<  7) | /* bus width */
1121                (((nsectors-1) & 0x7)     <<  4) | /* number of sectors */
1122                (info->gpmc_cs            <<  1) | /* ECC CS */
1123                (0x1));                            /* enable ECC */
1124
1125         writel(val, info->reg.gpmc_ecc_config);
1126
1127         /* Clear ecc and enable bits */
1128         writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
1129 }
1130
1131 static u8  bch4_polynomial[] = {0x28, 0x13, 0xcc, 0x39, 0x96, 0xac, 0x7f};
1132 static u8  bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2,
1133                                 0x97, 0x79, 0xe5, 0x24, 0xb5};
1134
1135 /**
1136  * _omap_calculate_ecc_bch - Generate ECC bytes for one sector
1137  * @mtd:        MTD device structure
1138  * @dat:        The pointer to data on which ecc is computed
1139  * @ecc_code:   The ecc_code buffer
1140  * @i:          The sector number (for a multi sector page)
1141  *
1142  * Support calculating of BCH4/8/16 ECC vectors for one sector
1143  * within a page. Sector number is in @i.
1144  */
1145 static int _omap_calculate_ecc_bch(struct mtd_info *mtd,
1146                                    const u_char *dat, u_char *ecc_calc, int i)
1147 {
1148         struct omap_nand_info *info = mtd_to_omap(mtd);
1149         int eccbytes    = info->nand.ecc.bytes;
1150         struct gpmc_nand_regs   *gpmc_regs = &info->reg;
1151         u8 *ecc_code;
1152         unsigned long bch_val1, bch_val2, bch_val3, bch_val4;
1153         u32 val;
1154         int j;
1155
1156         ecc_code = ecc_calc;
1157         switch (info->ecc_opt) {
1158         case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1159         case OMAP_ECC_BCH8_CODE_HW:
1160                 bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1161                 bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1162                 bch_val3 = readl(gpmc_regs->gpmc_bch_result2[i]);
1163                 bch_val4 = readl(gpmc_regs->gpmc_bch_result3[i]);
1164                 *ecc_code++ = (bch_val4 & 0xFF);
1165                 *ecc_code++ = ((bch_val3 >> 24) & 0xFF);
1166                 *ecc_code++ = ((bch_val3 >> 16) & 0xFF);
1167                 *ecc_code++ = ((bch_val3 >> 8) & 0xFF);
1168                 *ecc_code++ = (bch_val3 & 0xFF);
1169                 *ecc_code++ = ((bch_val2 >> 24) & 0xFF);
1170                 *ecc_code++ = ((bch_val2 >> 16) & 0xFF);
1171                 *ecc_code++ = ((bch_val2 >> 8) & 0xFF);
1172                 *ecc_code++ = (bch_val2 & 0xFF);
1173                 *ecc_code++ = ((bch_val1 >> 24) & 0xFF);
1174                 *ecc_code++ = ((bch_val1 >> 16) & 0xFF);
1175                 *ecc_code++ = ((bch_val1 >> 8) & 0xFF);
1176                 *ecc_code++ = (bch_val1 & 0xFF);
1177                 break;
1178         case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1179         case OMAP_ECC_BCH4_CODE_HW:
1180                 bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1181                 bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1182                 *ecc_code++ = ((bch_val2 >> 12) & 0xFF);
1183                 *ecc_code++ = ((bch_val2 >> 4) & 0xFF);
1184                 *ecc_code++ = ((bch_val2 & 0xF) << 4) |
1185                         ((bch_val1 >> 28) & 0xF);
1186                 *ecc_code++ = ((bch_val1 >> 20) & 0xFF);
1187                 *ecc_code++ = ((bch_val1 >> 12) & 0xFF);
1188                 *ecc_code++ = ((bch_val1 >> 4) & 0xFF);
1189                 *ecc_code++ = ((bch_val1 & 0xF) << 4);
1190                 break;
1191         case OMAP_ECC_BCH16_CODE_HW:
1192                 val = readl(gpmc_regs->gpmc_bch_result6[i]);
1193                 ecc_code[0]  = ((val >>  8) & 0xFF);
1194                 ecc_code[1]  = ((val >>  0) & 0xFF);
1195                 val = readl(gpmc_regs->gpmc_bch_result5[i]);
1196                 ecc_code[2]  = ((val >> 24) & 0xFF);
1197                 ecc_code[3]  = ((val >> 16) & 0xFF);
1198                 ecc_code[4]  = ((val >>  8) & 0xFF);
1199                 ecc_code[5]  = ((val >>  0) & 0xFF);
1200                 val = readl(gpmc_regs->gpmc_bch_result4[i]);
1201                 ecc_code[6]  = ((val >> 24) & 0xFF);
1202                 ecc_code[7]  = ((val >> 16) & 0xFF);
1203                 ecc_code[8]  = ((val >>  8) & 0xFF);
1204                 ecc_code[9]  = ((val >>  0) & 0xFF);
1205                 val = readl(gpmc_regs->gpmc_bch_result3[i]);
1206                 ecc_code[10] = ((val >> 24) & 0xFF);
1207                 ecc_code[11] = ((val >> 16) & 0xFF);
1208                 ecc_code[12] = ((val >>  8) & 0xFF);
1209                 ecc_code[13] = ((val >>  0) & 0xFF);
1210                 val = readl(gpmc_regs->gpmc_bch_result2[i]);
1211                 ecc_code[14] = ((val >> 24) & 0xFF);
1212                 ecc_code[15] = ((val >> 16) & 0xFF);
1213                 ecc_code[16] = ((val >>  8) & 0xFF);
1214                 ecc_code[17] = ((val >>  0) & 0xFF);
1215                 val = readl(gpmc_regs->gpmc_bch_result1[i]);
1216                 ecc_code[18] = ((val >> 24) & 0xFF);
1217                 ecc_code[19] = ((val >> 16) & 0xFF);
1218                 ecc_code[20] = ((val >>  8) & 0xFF);
1219                 ecc_code[21] = ((val >>  0) & 0xFF);
1220                 val = readl(gpmc_regs->gpmc_bch_result0[i]);
1221                 ecc_code[22] = ((val >> 24) & 0xFF);
1222                 ecc_code[23] = ((val >> 16) & 0xFF);
1223                 ecc_code[24] = ((val >>  8) & 0xFF);
1224                 ecc_code[25] = ((val >>  0) & 0xFF);
1225                 break;
1226         default:
1227                 return -EINVAL;
1228         }
1229
1230         /* ECC scheme specific syndrome customizations */
1231         switch (info->ecc_opt) {
1232         case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1233                 /* Add constant polynomial to remainder, so that
1234                  * ECC of blank pages results in 0x0 on reading back
1235                  */
1236                 for (j = 0; j < eccbytes; j++)
1237                         ecc_calc[j] ^= bch4_polynomial[j];
1238                 break;
1239         case OMAP_ECC_BCH4_CODE_HW:
1240                 /* Set  8th ECC byte as 0x0 for ROM compatibility */
1241                 ecc_calc[eccbytes - 1] = 0x0;
1242                 break;
1243         case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1244                 /* Add constant polynomial to remainder, so that
1245                  * ECC of blank pages results in 0x0 on reading back
1246                  */
1247                 for (j = 0; j < eccbytes; j++)
1248                         ecc_calc[j] ^= bch8_polynomial[j];
1249                 break;
1250         case OMAP_ECC_BCH8_CODE_HW:
1251                 /* Set 14th ECC byte as 0x0 for ROM compatibility */
1252                 ecc_calc[eccbytes - 1] = 0x0;
1253                 break;
1254         case OMAP_ECC_BCH16_CODE_HW:
1255                 break;
1256         default:
1257                 return -EINVAL;
1258         }
1259
1260         return 0;
1261 }
1262
1263 /**
1264  * omap_calculate_ecc_bch_sw - ECC generator for sector for SW based correction
1265  * @mtd:        MTD device structure
1266  * @dat:        The pointer to data on which ecc is computed
1267  * @ecc_code:   The ecc_code buffer
1268  *
1269  * Support calculating of BCH4/8/16 ECC vectors for one sector. This is used
1270  * when SW based correction is required as ECC is required for one sector
1271  * at a time.
1272  */
1273 static int omap_calculate_ecc_bch_sw(struct mtd_info *mtd,
1274                                      const u_char *dat, u_char *ecc_calc)
1275 {
1276         return _omap_calculate_ecc_bch(mtd, dat, ecc_calc, 0);
1277 }
1278
1279 /**
1280  * omap_calculate_ecc_bch_multi - Generate ECC for multiple sectors
1281  * @mtd:        MTD device structure
1282  * @dat:        The pointer to data on which ecc is computed
1283  * @ecc_code:   The ecc_code buffer
1284  *
1285  * Support calculating of BCH4/8/16 ecc vectors for the entire page in one go.
1286  */
1287 static int omap_calculate_ecc_bch_multi(struct mtd_info *mtd,
1288                                         const u_char *dat, u_char *ecc_calc)
1289 {
1290         struct omap_nand_info *info = mtd_to_omap(mtd);
1291         int eccbytes = info->nand.ecc.bytes;
1292         unsigned long nsectors;
1293         int i, ret;
1294
1295         nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
1296         for (i = 0; i < nsectors; i++) {
1297                 ret = _omap_calculate_ecc_bch(mtd, dat, ecc_calc, i);
1298                 if (ret)
1299                         return ret;
1300
1301                 ecc_calc += eccbytes;
1302         }
1303
1304         return 0;
1305 }
1306
1307 /**
1308  * erased_sector_bitflips - count bit flips
1309  * @data:       data sector buffer
1310  * @oob:        oob buffer
1311  * @info:       omap_nand_info
1312  *
1313  * Check the bit flips in erased page falls below correctable level.
1314  * If falls below, report the page as erased with correctable bit
1315  * flip, else report as uncorrectable page.
1316  */
1317 static int erased_sector_bitflips(u_char *data, u_char *oob,
1318                 struct omap_nand_info *info)
1319 {
1320         int flip_bits = 0, i;
1321
1322         for (i = 0; i < info->nand.ecc.size; i++) {
1323                 flip_bits += hweight8(~data[i]);
1324                 if (flip_bits > info->nand.ecc.strength)
1325                         return 0;
1326         }
1327
1328         for (i = 0; i < info->nand.ecc.bytes - 1; i++) {
1329                 flip_bits += hweight8(~oob[i]);
1330                 if (flip_bits > info->nand.ecc.strength)
1331                         return 0;
1332         }
1333
1334         /*
1335          * Bit flips falls in correctable level.
1336          * Fill data area with 0xFF
1337          */
1338         if (flip_bits) {
1339                 memset(data, 0xFF, info->nand.ecc.size);
1340                 memset(oob, 0xFF, info->nand.ecc.bytes);
1341         }
1342
1343         return flip_bits;
1344 }
1345
1346 /**
1347  * omap_elm_correct_data - corrects page data area in case error reported
1348  * @mtd:        MTD device structure
1349  * @data:       page data
1350  * @read_ecc:   ecc read from nand flash
1351  * @calc_ecc:   ecc read from HW ECC registers
1352  *
1353  * Calculated ecc vector reported as zero in case of non-error pages.
1354  * In case of non-zero ecc vector, first filter out erased-pages, and
1355  * then process data via ELM to detect bit-flips.
1356  */
1357 static int omap_elm_correct_data(struct mtd_info *mtd, u_char *data,
1358                                 u_char *read_ecc, u_char *calc_ecc)
1359 {
1360         struct omap_nand_info *info = mtd_to_omap(mtd);
1361         struct nand_ecc_ctrl *ecc = &info->nand.ecc;
1362         int eccsteps = info->nand.ecc.steps;
1363         int i , j, stat = 0;
1364         int eccflag, actual_eccbytes;
1365         struct elm_errorvec err_vec[ERROR_VECTOR_MAX];
1366         u_char *ecc_vec = calc_ecc;
1367         u_char *spare_ecc = read_ecc;
1368         u_char *erased_ecc_vec;
1369         u_char *buf;
1370         int bitflip_count;
1371         bool is_error_reported = false;
1372         u32 bit_pos, byte_pos, error_max, pos;
1373         int err;
1374
1375         switch (info->ecc_opt) {
1376         case OMAP_ECC_BCH4_CODE_HW:
1377                 /* omit  7th ECC byte reserved for ROM code compatibility */
1378                 actual_eccbytes = ecc->bytes - 1;
1379                 erased_ecc_vec = bch4_vector;
1380                 break;
1381         case OMAP_ECC_BCH8_CODE_HW:
1382                 /* omit 14th ECC byte reserved for ROM code compatibility */
1383                 actual_eccbytes = ecc->bytes - 1;
1384                 erased_ecc_vec = bch8_vector;
1385                 break;
1386         case OMAP_ECC_BCH16_CODE_HW:
1387                 actual_eccbytes = ecc->bytes;
1388                 erased_ecc_vec = bch16_vector;
1389                 break;
1390         default:
1391                 dev_err(&info->pdev->dev, "invalid driver configuration\n");
1392                 return -EINVAL;
1393         }
1394
1395         /* Initialize elm error vector to zero */
1396         memset(err_vec, 0, sizeof(err_vec));
1397
1398         for (i = 0; i < eccsteps ; i++) {
1399                 eccflag = 0;    /* initialize eccflag */
1400
1401                 /*
1402                  * Check any error reported,
1403                  * In case of error, non zero ecc reported.
1404                  */
1405                 for (j = 0; j < actual_eccbytes; j++) {
1406                         if (calc_ecc[j] != 0) {
1407                                 eccflag = 1; /* non zero ecc, error present */
1408                                 break;
1409                         }
1410                 }
1411
1412                 if (eccflag == 1) {
1413                         if (memcmp(calc_ecc, erased_ecc_vec,
1414                                                 actual_eccbytes) == 0) {
1415                                 /*
1416                                  * calc_ecc[] matches pattern for ECC(all 0xff)
1417                                  * so this is definitely an erased-page
1418                                  */
1419                         } else {
1420                                 buf = &data[info->nand.ecc.size * i];
1421                                 /*
1422                                  * count number of 0-bits in read_buf.
1423                                  * This check can be removed once a similar
1424                                  * check is introduced in generic NAND driver
1425                                  */
1426                                 bitflip_count = erased_sector_bitflips(
1427                                                 buf, read_ecc, info);
1428                                 if (bitflip_count) {
1429                                         /*
1430                                          * number of 0-bits within ECC limits
1431                                          * So this may be an erased-page
1432                                          */
1433                                         stat += bitflip_count;
1434                                 } else {
1435                                         /*
1436                                          * Too many 0-bits. It may be a
1437                                          * - programmed-page, OR
1438                                          * - erased-page with many bit-flips
1439                                          * So this page requires check by ELM
1440                                          */
1441                                         err_vec[i].error_reported = true;
1442                                         is_error_reported = true;
1443                                 }
1444                         }
1445                 }
1446
1447                 /* Update the ecc vector */
1448                 calc_ecc += ecc->bytes;
1449                 read_ecc += ecc->bytes;
1450         }
1451
1452         /* Check if any error reported */
1453         if (!is_error_reported)
1454                 return stat;
1455
1456         /* Decode BCH error using ELM module */
1457         elm_decode_bch_error_page(info->elm_dev, ecc_vec, err_vec);
1458
1459         err = 0;
1460         for (i = 0; i < eccsteps; i++) {
1461                 if (err_vec[i].error_uncorrectable) {
1462                         dev_err(&info->pdev->dev,
1463                                 "uncorrectable bit-flips found\n");
1464                         err = -EBADMSG;
1465                 } else if (err_vec[i].error_reported) {
1466                         for (j = 0; j < err_vec[i].error_count; j++) {
1467                                 switch (info->ecc_opt) {
1468                                 case OMAP_ECC_BCH4_CODE_HW:
1469                                         /* Add 4 bits to take care of padding */
1470                                         pos = err_vec[i].error_loc[j] +
1471                                                 BCH4_BIT_PAD;
1472                                         break;
1473                                 case OMAP_ECC_BCH8_CODE_HW:
1474                                 case OMAP_ECC_BCH16_CODE_HW:
1475                                         pos = err_vec[i].error_loc[j];
1476                                         break;
1477                                 default:
1478                                         return -EINVAL;
1479                                 }
1480                                 error_max = (ecc->size + actual_eccbytes) * 8;
1481                                 /* Calculate bit position of error */
1482                                 bit_pos = pos % 8;
1483
1484                                 /* Calculate byte position of error */
1485                                 byte_pos = (error_max - pos - 1) / 8;
1486
1487                                 if (pos < error_max) {
1488                                         if (byte_pos < 512) {
1489                                                 pr_debug("bitflip@dat[%d]=%x\n",
1490                                                      byte_pos, data[byte_pos]);
1491                                                 data[byte_pos] ^= 1 << bit_pos;
1492                                         } else {
1493                                                 pr_debug("bitflip@oob[%d]=%x\n",
1494                                                         (byte_pos - 512),
1495                                                      spare_ecc[byte_pos - 512]);
1496                                                 spare_ecc[byte_pos - 512] ^=
1497                                                         1 << bit_pos;
1498                                         }
1499                                 } else {
1500                                         dev_err(&info->pdev->dev,
1501                                                 "invalid bit-flip @ %d:%d\n",
1502                                                 byte_pos, bit_pos);
1503                                         err = -EBADMSG;
1504                                 }
1505                         }
1506                 }
1507
1508                 /* Update number of correctable errors */
1509                 stat += err_vec[i].error_count;
1510
1511                 /* Update page data with sector size */
1512                 data += ecc->size;
1513                 spare_ecc += ecc->bytes;
1514         }
1515
1516         return (err) ? err : stat;
1517 }
1518
1519 /**
1520  * omap_write_page_bch - BCH ecc based write page function for entire page
1521  * @mtd:                mtd info structure
1522  * @chip:               nand chip info structure
1523  * @buf:                data buffer
1524  * @oob_required:       must write chip->oob_poi to OOB
1525  * @page:               page
1526  *
1527  * Custom write page method evolved to support multi sector writing in one shot
1528  */
1529 static int omap_write_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
1530                                const uint8_t *buf, int oob_required, int page)
1531 {
1532         int ret;
1533         uint8_t *ecc_calc = chip->ecc.calc_buf;
1534
1535         nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1536
1537         /* Enable GPMC ecc engine */
1538         chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
1539
1540         /* Write data */
1541         chip->write_buf(mtd, buf, mtd->writesize);
1542
1543         /* Update ecc vector from GPMC result registers */
1544         omap_calculate_ecc_bch_multi(mtd, buf, &ecc_calc[0]);
1545
1546         ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
1547                                          chip->ecc.total);
1548         if (ret)
1549                 return ret;
1550
1551         /* Write ecc vector to OOB area */
1552         chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
1553
1554         return nand_prog_page_end_op(chip);
1555 }
1556
1557 /**
1558  * omap_write_subpage_bch - BCH hardware ECC based subpage write
1559  * @mtd:        mtd info structure
1560  * @chip:       nand chip info structure
1561  * @offset:     column address of subpage within the page
1562  * @data_len:   data length
1563  * @buf:        data buffer
1564  * @oob_required: must write chip->oob_poi to OOB
1565  * @page: page number to write
1566  *
1567  * OMAP optimized subpage write method.
1568  */
1569 static int omap_write_subpage_bch(struct mtd_info *mtd,
1570                                   struct nand_chip *chip, u32 offset,
1571                                   u32 data_len, const u8 *buf,
1572                                   int oob_required, int page)
1573 {
1574         u8 *ecc_calc = chip->ecc.calc_buf;
1575         int ecc_size      = chip->ecc.size;
1576         int ecc_bytes     = chip->ecc.bytes;
1577         int ecc_steps     = chip->ecc.steps;
1578         u32 start_step = offset / ecc_size;
1579         u32 end_step   = (offset + data_len - 1) / ecc_size;
1580         int step, ret = 0;
1581
1582         /*
1583          * Write entire page at one go as it would be optimal
1584          * as ECC is calculated by hardware.
1585          * ECC is calculated for all subpages but we choose
1586          * only what we want.
1587          */
1588         nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1589
1590         /* Enable GPMC ECC engine */
1591         chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
1592
1593         /* Write data */
1594         chip->write_buf(mtd, buf, mtd->writesize);
1595
1596         for (step = 0; step < ecc_steps; step++) {
1597                 /* mask ECC of un-touched subpages by padding 0xFF */
1598                 if (step < start_step || step > end_step)
1599                         memset(ecc_calc, 0xff, ecc_bytes);
1600                 else
1601                         ret = _omap_calculate_ecc_bch(mtd, buf, ecc_calc, step);
1602
1603                 if (ret)
1604                         return ret;
1605
1606                 buf += ecc_size;
1607                 ecc_calc += ecc_bytes;
1608         }
1609
1610         /* copy calculated ECC for whole page to chip->buffer->oob */
1611         /* this include masked-value(0xFF) for unwritten subpages */
1612         ecc_calc = chip->ecc.calc_buf;
1613         ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
1614                                          chip->ecc.total);
1615         if (ret)
1616                 return ret;
1617
1618         /* write OOB buffer to NAND device */
1619         chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
1620
1621         return nand_prog_page_end_op(chip);
1622 }
1623
1624 /**
1625  * omap_read_page_bch - BCH ecc based page read function for entire page
1626  * @mtd:                mtd info structure
1627  * @chip:               nand chip info structure
1628  * @buf:                buffer to store read data
1629  * @oob_required:       caller requires OOB data read to chip->oob_poi
1630  * @page:               page number to read
1631  *
1632  * For BCH ecc scheme, GPMC used for syndrome calculation and ELM module
1633  * used for error correction.
1634  * Custom method evolved to support ELM error correction & multi sector
1635  * reading. On reading page data area is read along with OOB data with
1636  * ecc engine enabled. ecc vector updated after read of OOB data.
1637  * For non error pages ecc vector reported as zero.
1638  */
1639 static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
1640                                 uint8_t *buf, int oob_required, int page)
1641 {
1642         uint8_t *ecc_calc = chip->ecc.calc_buf;
1643         uint8_t *ecc_code = chip->ecc.code_buf;
1644         int stat, ret;
1645         unsigned int max_bitflips = 0;
1646
1647         nand_read_page_op(chip, page, 0, NULL, 0);
1648
1649         /* Enable GPMC ecc engine */
1650         chip->ecc.hwctl(mtd, NAND_ECC_READ);
1651
1652         /* Read data */
1653         chip->read_buf(mtd, buf, mtd->writesize);
1654
1655         /* Read oob bytes */
1656         nand_change_read_column_op(chip,
1657                                    mtd->writesize + BADBLOCK_MARKER_LENGTH,
1658                                    chip->oob_poi + BADBLOCK_MARKER_LENGTH,
1659                                    chip->ecc.total, false);
1660
1661         /* Calculate ecc bytes */
1662         omap_calculate_ecc_bch_multi(mtd, buf, ecc_calc);
1663
1664         ret = mtd_ooblayout_get_eccbytes(mtd, ecc_code, chip->oob_poi, 0,
1665                                          chip->ecc.total);
1666         if (ret)
1667                 return ret;
1668
1669         stat = chip->ecc.correct(mtd, buf, ecc_code, ecc_calc);
1670
1671         if (stat < 0) {
1672                 mtd->ecc_stats.failed++;
1673         } else {
1674                 mtd->ecc_stats.corrected += stat;
1675                 max_bitflips = max_t(unsigned int, max_bitflips, stat);
1676         }
1677
1678         return max_bitflips;
1679 }
1680
1681 /**
1682  * is_elm_present - checks for presence of ELM module by scanning DT nodes
1683  * @omap_nand_info: NAND device structure containing platform data
1684  */
1685 static bool is_elm_present(struct omap_nand_info *info,
1686                            struct device_node *elm_node)
1687 {
1688         struct platform_device *pdev;
1689
1690         /* check whether elm-id is passed via DT */
1691         if (!elm_node) {
1692                 dev_err(&info->pdev->dev, "ELM devicetree node not found\n");
1693                 return false;
1694         }
1695         pdev = of_find_device_by_node(elm_node);
1696         /* check whether ELM device is registered */
1697         if (!pdev) {
1698                 dev_err(&info->pdev->dev, "ELM device not found\n");
1699                 return false;
1700         }
1701         /* ELM module available, now configure it */
1702         info->elm_dev = &pdev->dev;
1703         return true;
1704 }
1705
1706 static bool omap2_nand_ecc_check(struct omap_nand_info *info)
1707 {
1708         bool ecc_needs_bch, ecc_needs_omap_bch, ecc_needs_elm;
1709
1710         switch (info->ecc_opt) {
1711         case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1712         case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1713                 ecc_needs_omap_bch = false;
1714                 ecc_needs_bch = true;
1715                 ecc_needs_elm = false;
1716                 break;
1717         case OMAP_ECC_BCH4_CODE_HW:
1718         case OMAP_ECC_BCH8_CODE_HW:
1719         case OMAP_ECC_BCH16_CODE_HW:
1720                 ecc_needs_omap_bch = true;
1721                 ecc_needs_bch = false;
1722                 ecc_needs_elm = true;
1723                 break;
1724         default:
1725                 ecc_needs_omap_bch = false;
1726                 ecc_needs_bch = false;
1727                 ecc_needs_elm = false;
1728                 break;
1729         }
1730
1731         if (ecc_needs_bch && !IS_ENABLED(CONFIG_MTD_NAND_ECC_BCH)) {
1732                 dev_err(&info->pdev->dev,
1733                         "CONFIG_MTD_NAND_ECC_BCH not enabled\n");
1734                 return false;
1735         }
1736         if (ecc_needs_omap_bch && !IS_ENABLED(CONFIG_MTD_NAND_OMAP_BCH)) {
1737                 dev_err(&info->pdev->dev,
1738                         "CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
1739                 return false;
1740         }
1741         if (ecc_needs_elm && !is_elm_present(info, info->elm_of_node)) {
1742                 dev_err(&info->pdev->dev, "ELM not available\n");
1743                 return false;
1744         }
1745
1746         return true;
1747 }
1748
1749 static const char * const nand_xfer_types[] = {
1750         [NAND_OMAP_PREFETCH_POLLED] = "prefetch-polled",
1751         [NAND_OMAP_POLLED] = "polled",
1752         [NAND_OMAP_PREFETCH_DMA] = "prefetch-dma",
1753         [NAND_OMAP_PREFETCH_IRQ] = "prefetch-irq",
1754 };
1755
1756 static int omap_get_dt_info(struct device *dev, struct omap_nand_info *info)
1757 {
1758         struct device_node *child = dev->of_node;
1759         int i;
1760         const char *s;
1761         u32 cs;
1762
1763         if (of_property_read_u32(child, "reg", &cs) < 0) {
1764                 dev_err(dev, "reg not found in DT\n");
1765                 return -EINVAL;
1766         }
1767
1768         info->gpmc_cs = cs;
1769
1770         /* detect availability of ELM module. Won't be present pre-OMAP4 */
1771         info->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0);
1772         if (!info->elm_of_node) {
1773                 info->elm_of_node = of_parse_phandle(child, "elm_id", 0);
1774                 if (!info->elm_of_node)
1775                         dev_dbg(dev, "ti,elm-id not in DT\n");
1776         }
1777
1778         /* select ecc-scheme for NAND */
1779         if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) {
1780                 dev_err(dev, "ti,nand-ecc-opt not found\n");
1781                 return -EINVAL;
1782         }
1783
1784         if (!strcmp(s, "sw")) {
1785                 info->ecc_opt = OMAP_ECC_HAM1_CODE_SW;
1786         } else if (!strcmp(s, "ham1") ||
1787                    !strcmp(s, "hw") || !strcmp(s, "hw-romcode")) {
1788                 info->ecc_opt = OMAP_ECC_HAM1_CODE_HW;
1789         } else if (!strcmp(s, "bch4")) {
1790                 if (info->elm_of_node)
1791                         info->ecc_opt = OMAP_ECC_BCH4_CODE_HW;
1792                 else
1793                         info->ecc_opt = OMAP_ECC_BCH4_CODE_HW_DETECTION_SW;
1794         } else if (!strcmp(s, "bch8")) {
1795                 if (info->elm_of_node)
1796                         info->ecc_opt = OMAP_ECC_BCH8_CODE_HW;
1797                 else
1798                         info->ecc_opt = OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
1799         } else if (!strcmp(s, "bch16")) {
1800                 info->ecc_opt = OMAP_ECC_BCH16_CODE_HW;
1801         } else {
1802                 dev_err(dev, "unrecognized value for ti,nand-ecc-opt\n");
1803                 return -EINVAL;
1804         }
1805
1806         /* select data transfer mode */
1807         if (!of_property_read_string(child, "ti,nand-xfer-type", &s)) {
1808                 for (i = 0; i < ARRAY_SIZE(nand_xfer_types); i++) {
1809                         if (!strcasecmp(s, nand_xfer_types[i])) {
1810                                 info->xfer_type = i;
1811                                 return 0;
1812                         }
1813                 }
1814
1815                 dev_err(dev, "unrecognized value for ti,nand-xfer-type\n");
1816                 return -EINVAL;
1817         }
1818
1819         return 0;
1820 }
1821
1822 static int omap_ooblayout_ecc(struct mtd_info *mtd, int section,
1823                               struct mtd_oob_region *oobregion)
1824 {
1825         struct omap_nand_info *info = mtd_to_omap(mtd);
1826         struct nand_chip *chip = &info->nand;
1827         int off = BADBLOCK_MARKER_LENGTH;
1828
1829         if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1830             !(chip->options & NAND_BUSWIDTH_16))
1831                 off = 1;
1832
1833         if (section)
1834                 return -ERANGE;
1835
1836         oobregion->offset = off;
1837         oobregion->length = chip->ecc.total;
1838
1839         return 0;
1840 }
1841
1842 static int omap_ooblayout_free(struct mtd_info *mtd, int section,
1843                                struct mtd_oob_region *oobregion)
1844 {
1845         struct omap_nand_info *info = mtd_to_omap(mtd);
1846         struct nand_chip *chip = &info->nand;
1847         int off = BADBLOCK_MARKER_LENGTH;
1848
1849         if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1850             !(chip->options & NAND_BUSWIDTH_16))
1851                 off = 1;
1852
1853         if (section)
1854                 return -ERANGE;
1855
1856         off += chip->ecc.total;
1857         if (off >= mtd->oobsize)
1858                 return -ERANGE;
1859
1860         oobregion->offset = off;
1861         oobregion->length = mtd->oobsize - off;
1862
1863         return 0;
1864 }
1865
1866 static const struct mtd_ooblayout_ops omap_ooblayout_ops = {
1867         .ecc = omap_ooblayout_ecc,
1868         .free = omap_ooblayout_free,
1869 };
1870
1871 static int omap_sw_ooblayout_ecc(struct mtd_info *mtd, int section,
1872                                  struct mtd_oob_region *oobregion)
1873 {
1874         struct nand_chip *chip = mtd_to_nand(mtd);
1875         int off = BADBLOCK_MARKER_LENGTH;
1876
1877         if (section >= chip->ecc.steps)
1878                 return -ERANGE;
1879
1880         /*
1881          * When SW correction is employed, one OMAP specific marker byte is
1882          * reserved after each ECC step.
1883          */
1884         oobregion->offset = off + (section * (chip->ecc.bytes + 1));
1885         oobregion->length = chip->ecc.bytes;
1886
1887         return 0;
1888 }
1889
1890 static int omap_sw_ooblayout_free(struct mtd_info *mtd, int section,
1891                                   struct mtd_oob_region *oobregion)
1892 {
1893         struct nand_chip *chip = mtd_to_nand(mtd);
1894         int off = BADBLOCK_MARKER_LENGTH;
1895
1896         if (section)
1897                 return -ERANGE;
1898
1899         /*
1900          * When SW correction is employed, one OMAP specific marker byte is
1901          * reserved after each ECC step.
1902          */
1903         off += ((chip->ecc.bytes + 1) * chip->ecc.steps);
1904         if (off >= mtd->oobsize)
1905                 return -ERANGE;
1906
1907         oobregion->offset = off;
1908         oobregion->length = mtd->oobsize - off;
1909
1910         return 0;
1911 }
1912
1913 static const struct mtd_ooblayout_ops omap_sw_ooblayout_ops = {
1914         .ecc = omap_sw_ooblayout_ecc,
1915         .free = omap_sw_ooblayout_free,
1916 };
1917
1918 static int omap_nand_probe(struct platform_device *pdev)
1919 {
1920         struct omap_nand_info           *info;
1921         struct mtd_info                 *mtd;
1922         struct nand_chip                *nand_chip;
1923         int                             err;
1924         dma_cap_mask_t                  mask;
1925         struct resource                 *res;
1926         struct device                   *dev = &pdev->dev;
1927         int                             min_oobbytes = BADBLOCK_MARKER_LENGTH;
1928         int                             oobbytes_per_step;
1929
1930         info = devm_kzalloc(&pdev->dev, sizeof(struct omap_nand_info),
1931                                 GFP_KERNEL);
1932         if (!info)
1933                 return -ENOMEM;
1934
1935         info->pdev = pdev;
1936
1937         err = omap_get_dt_info(dev, info);
1938         if (err)
1939                 return err;
1940
1941         info->ops = gpmc_omap_get_nand_ops(&info->reg, info->gpmc_cs);
1942         if (!info->ops) {
1943                 dev_err(&pdev->dev, "Failed to get GPMC->NAND interface\n");
1944                 return -ENODEV;
1945         }
1946
1947         nand_chip               = &info->nand;
1948         mtd                     = nand_to_mtd(nand_chip);
1949         mtd->dev.parent         = &pdev->dev;
1950         nand_chip->ecc.priv     = NULL;
1951         nand_set_flash_node(nand_chip, dev->of_node);
1952
1953         if (!mtd->name) {
1954                 mtd->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
1955                                            "omap2-nand.%d", info->gpmc_cs);
1956                 if (!mtd->name) {
1957                         dev_err(&pdev->dev, "Failed to set MTD name\n");
1958                         return -ENOMEM;
1959                 }
1960         }
1961
1962         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1963         nand_chip->IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res);
1964         if (IS_ERR(nand_chip->IO_ADDR_R))
1965                 return PTR_ERR(nand_chip->IO_ADDR_R);
1966
1967         info->phys_base = res->start;
1968
1969         nand_chip->controller = &omap_gpmc_controller;
1970
1971         nand_chip->IO_ADDR_W = nand_chip->IO_ADDR_R;
1972         nand_chip->cmd_ctrl  = omap_hwcontrol;
1973
1974         info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "rb",
1975                                                     GPIOD_IN);
1976         if (IS_ERR(info->ready_gpiod)) {
1977                 dev_err(dev, "failed to get ready gpio\n");
1978                 return PTR_ERR(info->ready_gpiod);
1979         }
1980
1981         /*
1982          * If RDY/BSY line is connected to OMAP then use the omap ready
1983          * function and the generic nand_wait function which reads the status
1984          * register after monitoring the RDY/BSY line. Otherwise use a standard
1985          * chip delay which is slightly more than tR (AC Timing) of the NAND
1986          * device and read status register until you get a failure or success
1987          */
1988         if (info->ready_gpiod) {
1989                 nand_chip->dev_ready = omap_dev_ready;
1990                 nand_chip->chip_delay = 0;
1991         } else {
1992                 nand_chip->waitfunc = omap_wait;
1993                 nand_chip->chip_delay = 50;
1994         }
1995
1996         if (info->flash_bbt)
1997                 nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
1998
1999         /* scan NAND device connected to chip controller */
2000         nand_chip->options |= info->devsize & NAND_BUSWIDTH_16;
2001         err = nand_scan_ident(mtd, 1, NULL);
2002         if (err) {
2003                 dev_err(&info->pdev->dev,
2004                         "scan failed, may be bus-width mismatch\n");
2005                 goto return_error;
2006         }
2007
2008         if (nand_chip->bbt_options & NAND_BBT_USE_FLASH)
2009                 nand_chip->bbt_options |= NAND_BBT_NO_OOB;
2010         else
2011                 nand_chip->options |= NAND_SKIP_BBTSCAN;
2012
2013         /* re-populate low-level callbacks based on xfer modes */
2014         switch (info->xfer_type) {
2015         case NAND_OMAP_PREFETCH_POLLED:
2016                 nand_chip->read_buf   = omap_read_buf_pref;
2017                 nand_chip->write_buf  = omap_write_buf_pref;
2018                 break;
2019
2020         case NAND_OMAP_POLLED:
2021                 /* Use nand_base defaults for {read,write}_buf */
2022                 break;
2023
2024         case NAND_OMAP_PREFETCH_DMA:
2025                 dma_cap_zero(mask);
2026                 dma_cap_set(DMA_SLAVE, mask);
2027                 info->dma = dma_request_chan(pdev->dev.parent, "rxtx");
2028
2029                 if (IS_ERR(info->dma)) {
2030                         dev_err(&pdev->dev, "DMA engine request failed\n");
2031                         err = PTR_ERR(info->dma);
2032                         goto return_error;
2033                 } else {
2034                         struct dma_slave_config cfg;
2035
2036                         memset(&cfg, 0, sizeof(cfg));
2037                         cfg.src_addr = info->phys_base;
2038                         cfg.dst_addr = info->phys_base;
2039                         cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
2040                         cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
2041                         cfg.src_maxburst = 16;
2042                         cfg.dst_maxburst = 16;
2043                         err = dmaengine_slave_config(info->dma, &cfg);
2044                         if (err) {
2045                                 dev_err(&pdev->dev, "DMA engine slave config failed: %d\n",
2046                                         err);
2047                                 goto return_error;
2048                         }
2049                         nand_chip->read_buf   = omap_read_buf_dma_pref;
2050                         nand_chip->write_buf  = omap_write_buf_dma_pref;
2051                 }
2052                 break;
2053
2054         case NAND_OMAP_PREFETCH_IRQ:
2055                 info->gpmc_irq_fifo = platform_get_irq(pdev, 0);
2056                 if (info->gpmc_irq_fifo <= 0) {
2057                         dev_err(&pdev->dev, "error getting fifo irq\n");
2058                         err = -ENODEV;
2059                         goto return_error;
2060                 }
2061                 err = devm_request_irq(&pdev->dev, info->gpmc_irq_fifo,
2062                                         omap_nand_irq, IRQF_SHARED,
2063                                         "gpmc-nand-fifo", info);
2064                 if (err) {
2065                         dev_err(&pdev->dev, "requesting irq(%d) error:%d",
2066                                                 info->gpmc_irq_fifo, err);
2067                         info->gpmc_irq_fifo = 0;
2068                         goto return_error;
2069                 }
2070
2071                 info->gpmc_irq_count = platform_get_irq(pdev, 1);
2072                 if (info->gpmc_irq_count <= 0) {
2073                         dev_err(&pdev->dev, "error getting count irq\n");
2074                         err = -ENODEV;
2075                         goto return_error;
2076                 }
2077                 err = devm_request_irq(&pdev->dev, info->gpmc_irq_count,
2078                                         omap_nand_irq, IRQF_SHARED,
2079                                         "gpmc-nand-count", info);
2080                 if (err) {
2081                         dev_err(&pdev->dev, "requesting irq(%d) error:%d",
2082                                                 info->gpmc_irq_count, err);
2083                         info->gpmc_irq_count = 0;
2084                         goto return_error;
2085                 }
2086
2087                 nand_chip->read_buf  = omap_read_buf_irq_pref;
2088                 nand_chip->write_buf = omap_write_buf_irq_pref;
2089
2090                 break;
2091
2092         default:
2093                 dev_err(&pdev->dev,
2094                         "xfer_type(%d) not supported!\n", info->xfer_type);
2095                 err = -EINVAL;
2096                 goto return_error;
2097         }
2098
2099         if (!omap2_nand_ecc_check(info)) {
2100                 err = -EINVAL;
2101                 goto return_error;
2102         }
2103
2104         /*
2105          * Bail out earlier to let NAND_ECC_SOFT code create its own
2106          * ooblayout instead of using ours.
2107          */
2108         if (info->ecc_opt == OMAP_ECC_HAM1_CODE_SW) {
2109                 nand_chip->ecc.mode = NAND_ECC_SOFT;
2110                 nand_chip->ecc.algo = NAND_ECC_HAMMING;
2111                 goto scan_tail;
2112         }
2113
2114         /* populate MTD interface based on ECC scheme */
2115         switch (info->ecc_opt) {
2116         case OMAP_ECC_HAM1_CODE_HW:
2117                 pr_info("nand: using OMAP_ECC_HAM1_CODE_HW\n");
2118                 nand_chip->ecc.mode             = NAND_ECC_HW;
2119                 nand_chip->ecc.bytes            = 3;
2120                 nand_chip->ecc.size             = 512;
2121                 nand_chip->ecc.strength         = 1;
2122                 nand_chip->ecc.calculate        = omap_calculate_ecc;
2123                 nand_chip->ecc.hwctl            = omap_enable_hwecc;
2124                 nand_chip->ecc.correct          = omap_correct_data;
2125                 mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2126                 oobbytes_per_step               = nand_chip->ecc.bytes;
2127
2128                 if (!(nand_chip->options & NAND_BUSWIDTH_16))
2129                         min_oobbytes            = 1;
2130
2131                 break;
2132
2133         case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
2134                 pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n");
2135                 nand_chip->ecc.mode             = NAND_ECC_HW;
2136                 nand_chip->ecc.size             = 512;
2137                 nand_chip->ecc.bytes            = 7;
2138                 nand_chip->ecc.strength         = 4;
2139                 nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
2140                 nand_chip->ecc.correct          = nand_bch_correct_data;
2141                 nand_chip->ecc.calculate        = omap_calculate_ecc_bch_sw;
2142                 mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2143                 /* Reserve one byte for the OMAP marker */
2144                 oobbytes_per_step               = nand_chip->ecc.bytes + 1;
2145                 /* software bch library is used for locating errors */
2146                 nand_chip->ecc.priv             = nand_bch_init(mtd);
2147                 if (!nand_chip->ecc.priv) {
2148                         dev_err(&info->pdev->dev, "unable to use BCH library\n");
2149                         err = -EINVAL;
2150                         goto return_error;
2151                 }
2152                 break;
2153
2154         case OMAP_ECC_BCH4_CODE_HW:
2155                 pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n");
2156                 nand_chip->ecc.mode             = NAND_ECC_HW;
2157                 nand_chip->ecc.size             = 512;
2158                 /* 14th bit is kept reserved for ROM-code compatibility */
2159                 nand_chip->ecc.bytes            = 7 + 1;
2160                 nand_chip->ecc.strength         = 4;
2161                 nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
2162                 nand_chip->ecc.correct          = omap_elm_correct_data;
2163                 nand_chip->ecc.read_page        = omap_read_page_bch;
2164                 nand_chip->ecc.write_page       = omap_write_page_bch;
2165                 nand_chip->ecc.write_subpage    = omap_write_subpage_bch;
2166                 mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2167                 oobbytes_per_step               = nand_chip->ecc.bytes;
2168
2169                 err = elm_config(info->elm_dev, BCH4_ECC,
2170                                  mtd->writesize / nand_chip->ecc.size,
2171                                  nand_chip->ecc.size, nand_chip->ecc.bytes);
2172                 if (err < 0)
2173                         goto return_error;
2174                 break;
2175
2176         case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
2177                 pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
2178                 nand_chip->ecc.mode             = NAND_ECC_HW;
2179                 nand_chip->ecc.size             = 512;
2180                 nand_chip->ecc.bytes            = 13;
2181                 nand_chip->ecc.strength         = 8;
2182                 nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
2183                 nand_chip->ecc.correct          = nand_bch_correct_data;
2184                 nand_chip->ecc.calculate        = omap_calculate_ecc_bch_sw;
2185                 mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2186                 /* Reserve one byte for the OMAP marker */
2187                 oobbytes_per_step               = nand_chip->ecc.bytes + 1;
2188                 /* software bch library is used for locating errors */
2189                 nand_chip->ecc.priv             = nand_bch_init(mtd);
2190                 if (!nand_chip->ecc.priv) {
2191                         dev_err(&info->pdev->dev, "unable to use BCH library\n");
2192                         err = -EINVAL;
2193                         goto return_error;
2194                 }
2195                 break;
2196
2197         case OMAP_ECC_BCH8_CODE_HW:
2198                 pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n");
2199                 nand_chip->ecc.mode             = NAND_ECC_HW;
2200                 nand_chip->ecc.size             = 512;
2201                 /* 14th bit is kept reserved for ROM-code compatibility */
2202                 nand_chip->ecc.bytes            = 13 + 1;
2203                 nand_chip->ecc.strength         = 8;
2204                 nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
2205                 nand_chip->ecc.correct          = omap_elm_correct_data;
2206                 nand_chip->ecc.read_page        = omap_read_page_bch;
2207                 nand_chip->ecc.write_page       = omap_write_page_bch;
2208                 nand_chip->ecc.write_subpage    = omap_write_subpage_bch;
2209                 mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2210                 oobbytes_per_step               = nand_chip->ecc.bytes;
2211
2212                 err = elm_config(info->elm_dev, BCH8_ECC,
2213                                  mtd->writesize / nand_chip->ecc.size,
2214                                  nand_chip->ecc.size, nand_chip->ecc.bytes);
2215                 if (err < 0)
2216                         goto return_error;
2217
2218                 break;
2219
2220         case OMAP_ECC_BCH16_CODE_HW:
2221                 pr_info("using OMAP_ECC_BCH16_CODE_HW ECC scheme\n");
2222                 nand_chip->ecc.mode             = NAND_ECC_HW;
2223                 nand_chip->ecc.size             = 512;
2224                 nand_chip->ecc.bytes            = 26;
2225                 nand_chip->ecc.strength         = 16;
2226                 nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
2227                 nand_chip->ecc.correct          = omap_elm_correct_data;
2228                 nand_chip->ecc.read_page        = omap_read_page_bch;
2229                 nand_chip->ecc.write_page       = omap_write_page_bch;
2230                 nand_chip->ecc.write_subpage    = omap_write_subpage_bch;
2231                 mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2232                 oobbytes_per_step               = nand_chip->ecc.bytes;
2233
2234                 err = elm_config(info->elm_dev, BCH16_ECC,
2235                                  mtd->writesize / nand_chip->ecc.size,
2236                                  nand_chip->ecc.size, nand_chip->ecc.bytes);
2237                 if (err < 0)
2238                         goto return_error;
2239
2240                 break;
2241         default:
2242                 dev_err(&info->pdev->dev, "invalid or unsupported ECC scheme\n");
2243                 err = -EINVAL;
2244                 goto return_error;
2245         }
2246
2247         /* check if NAND device's OOB is enough to store ECC signatures */
2248         min_oobbytes += (oobbytes_per_step *
2249                          (mtd->writesize / nand_chip->ecc.size));
2250         if (mtd->oobsize < min_oobbytes) {
2251                 dev_err(&info->pdev->dev,
2252                         "not enough OOB bytes required = %d, available=%d\n",
2253                         min_oobbytes, mtd->oobsize);
2254                 err = -EINVAL;
2255                 goto return_error;
2256         }
2257
2258 scan_tail:
2259         /* second phase scan */
2260         err = nand_scan_tail(mtd);
2261         if (err)
2262                 goto return_error;
2263
2264         err = mtd_device_register(mtd, NULL, 0);
2265         if (err)
2266                 goto return_error;
2267
2268         platform_set_drvdata(pdev, mtd);
2269
2270         return 0;
2271
2272 return_error:
2273         if (!IS_ERR_OR_NULL(info->dma))
2274                 dma_release_channel(info->dma);
2275         if (nand_chip->ecc.priv) {
2276                 nand_bch_free(nand_chip->ecc.priv);
2277                 nand_chip->ecc.priv = NULL;
2278         }
2279         return err;
2280 }
2281
2282 static int omap_nand_remove(struct platform_device *pdev)
2283 {
2284         struct mtd_info *mtd = platform_get_drvdata(pdev);
2285         struct nand_chip *nand_chip = mtd_to_nand(mtd);
2286         struct omap_nand_info *info = mtd_to_omap(mtd);
2287         if (nand_chip->ecc.priv) {
2288                 nand_bch_free(nand_chip->ecc.priv);
2289                 nand_chip->ecc.priv = NULL;
2290         }
2291         if (info->dma)
2292                 dma_release_channel(info->dma);
2293         nand_release(mtd);
2294         return 0;
2295 }
2296
2297 static const struct of_device_id omap_nand_ids[] = {
2298         { .compatible = "ti,omap2-nand", },
2299         {},
2300 };
2301 MODULE_DEVICE_TABLE(of, omap_nand_ids);
2302
2303 static struct platform_driver omap_nand_driver = {
2304         .probe          = omap_nand_probe,
2305         .remove         = omap_nand_remove,
2306         .driver         = {
2307                 .name   = DRIVER_NAME,
2308                 .of_match_table = of_match_ptr(omap_nand_ids),
2309         },
2310 };
2311
2312 module_platform_driver(omap_nand_driver);
2313
2314 MODULE_ALIAS("platform:" DRIVER_NAME);
2315 MODULE_LICENSE("GPL");
2316 MODULE_DESCRIPTION("Glue layer for NAND flash on TI OMAP boards");