drivers/dma/stm32-dma.c

   1 /*
   2  * Driver for STM32 DMA controller
   3  *
   4  * Inspired by dma-jz4740.c and tegra20-apb-dma.c
   5  *
   6  * Copyright (C) M'boumba Cedric Madianga 2015
   7  * Author: M'boumba Cedric Madianga <[email protected]>
   8  *         Pierre-Yves Mordret <[email protected]>
   9  *
  10  * License terms:  GNU General Public License (GPL), version 2
  11  */
  12
  13 #include <linux/clk.h>
  14 #include <linux/delay.h>
  15 #include <linux/dmaengine.h>
  16 #include <linux/dma-mapping.h>
  17 #include <linux/err.h>
  18 #include <linux/init.h>
  19 #include <linux/jiffies.h>
  20 #include <linux/list.h>
  21 #include <linux/module.h>
  22 #include <linux/of.h>
  23 #include <linux/of_device.h>
  24 #include <linux/of_dma.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/reset.h>
  27 #include <linux/sched.h>
  28 #include <linux/slab.h>
  29
  30 #include "virt-dma.h"
  31
  32 #define STM32_DMA_LISR                  0x0000 /* DMA Low Int Status Reg */
  33 #define STM32_DMA_HISR                  0x0004 /* DMA High Int Status Reg */
  34 #define STM32_DMA_LIFCR                 0x0008 /* DMA Low Int Flag Clear Reg */
  35 #define STM32_DMA_HIFCR                 0x000c /* DMA High Int Flag Clear Reg */
  36 #define STM32_DMA_TCI                   BIT(5) /* Transfer Complete Interrupt */
  37 #define STM32_DMA_HTI                   BIT(4) /* Half Transfer Interrupt */
  38 #define STM32_DMA_TEI                   BIT(3) /* Transfer Error Interrupt */
  39 #define STM32_DMA_DMEI                  BIT(2) /* Direct Mode Error Interrupt */
  40 #define STM32_DMA_FEI                   BIT(0) /* FIFO Error Interrupt */
  41 #define STM32_DMA_MASKI                 (STM32_DMA_TCI \
  42                                          | STM32_DMA_TEI \
  43                                          | STM32_DMA_DMEI \
  44                                          | STM32_DMA_FEI)
  45
  46 /* DMA Stream x Configuration Register */
  47 #define STM32_DMA_SCR(x)                (0x0010 + 0x18 * (x)) /* x = 0..7 */
  48 #define STM32_DMA_SCR_REQ(n)            ((n & 0x7) << 25)
  49 #define STM32_DMA_SCR_MBURST_MASK       GENMASK(24, 23)
  50 #define STM32_DMA_SCR_MBURST(n)         ((n & 0x3) << 23)
  51 #define STM32_DMA_SCR_PBURST_MASK       GENMASK(22, 21)
  52 #define STM32_DMA_SCR_PBURST(n)         ((n & 0x3) << 21)
  53 #define STM32_DMA_SCR_PL_MASK           GENMASK(17, 16)
  54 #define STM32_DMA_SCR_PL(n)             ((n & 0x3) << 16)
  55 #define STM32_DMA_SCR_MSIZE_MASK        GENMASK(14, 13)
  56 #define STM32_DMA_SCR_MSIZE(n)          ((n & 0x3) << 13)
  57 #define STM32_DMA_SCR_PSIZE_MASK        GENMASK(12, 11)
  58 #define STM32_DMA_SCR_PSIZE(n)          ((n & 0x3) << 11)
  59 #define STM32_DMA_SCR_PSIZE_GET(n)      ((n & STM32_DMA_SCR_PSIZE_MASK) >> 11)
  60 #define STM32_DMA_SCR_DIR_MASK          GENMASK(7, 6)
  61 #define STM32_DMA_SCR_DIR(n)            ((n & 0x3) << 6)
  62 #define STM32_DMA_SCR_CT                BIT(19) /* Target in double buffer */
  63 #define STM32_DMA_SCR_DBM               BIT(18) /* Double Buffer Mode */
  64 #define STM32_DMA_SCR_PINCOS            BIT(15) /* Peripheral inc offset size */
  65 #define STM32_DMA_SCR_MINC              BIT(10) /* Memory increment mode */
  66 #define STM32_DMA_SCR_PINC              BIT(9) /* Peripheral increment mode */
  67 #define STM32_DMA_SCR_CIRC              BIT(8) /* Circular mode */
  68 #define STM32_DMA_SCR_PFCTRL            BIT(5) /* Peripheral Flow Controller */
  69 #define STM32_DMA_SCR_TCIE              BIT(4) /* Transfer Complete Int Enable
  70                                                 */
  71 #define STM32_DMA_SCR_TEIE              BIT(2) /* Transfer Error Int Enable */
  72 #define STM32_DMA_SCR_DMEIE             BIT(1) /* Direct Mode Err Int Enable */
  73 #define STM32_DMA_SCR_EN                BIT(0) /* Stream Enable */
  74 #define STM32_DMA_SCR_CFG_MASK          (STM32_DMA_SCR_PINC \
  75                                         | STM32_DMA_SCR_MINC \
  76                                         | STM32_DMA_SCR_PINCOS \
  77                                         | STM32_DMA_SCR_PL_MASK)
  78 #define STM32_DMA_SCR_IRQ_MASK          (STM32_DMA_SCR_TCIE \
  79                                         | STM32_DMA_SCR_TEIE \
  80                                         | STM32_DMA_SCR_DMEIE)
  81
  82 /* DMA Stream x number of data register */
  83 #define STM32_DMA_SNDTR(x)              (0x0014 + 0x18 * (x))
  84
  85 /* DMA stream peripheral address register */
  86 #define STM32_DMA_SPAR(x)               (0x0018 + 0x18 * (x))
  87
  88 /* DMA stream x memory 0 address register */
  89 #define STM32_DMA_SM0AR(x)              (0x001c + 0x18 * (x))
  90
  91 /* DMA stream x memory 1 address register */
  92 #define STM32_DMA_SM1AR(x)              (0x0020 + 0x18 * (x))
  93
  94 /* DMA stream x FIFO control register */
  95 #define STM32_DMA_SFCR(x)               (0x0024 + 0x18 * (x))
  96 #define STM32_DMA_SFCR_FTH_MASK         GENMASK(1, 0)
  97 #define STM32_DMA_SFCR_FTH(n)           (n & STM32_DMA_SFCR_FTH_MASK)
  98 #define STM32_DMA_SFCR_FEIE             BIT(7) /* FIFO error interrupt enable */
  99 #define STM32_DMA_SFCR_DMDIS            BIT(2) /* Direct mode disable */
 100 #define STM32_DMA_SFCR_MASK             (STM32_DMA_SFCR_FEIE \
 101                                         | STM32_DMA_SFCR_DMDIS)
 102
 103 /* DMA direction */
 104 #define STM32_DMA_DEV_TO_MEM            0x00
 105 #define STM32_DMA_MEM_TO_DEV            0x01
 106 #define STM32_DMA_MEM_TO_MEM            0x02
 107
 108 /* DMA priority level */
 109 #define STM32_DMA_PRIORITY_LOW          0x00
 110 #define STM32_DMA_PRIORITY_MEDIUM       0x01
 111 #define STM32_DMA_PRIORITY_HIGH         0x02
 112 #define STM32_DMA_PRIORITY_VERY_HIGH    0x03
 113
 114 /* DMA FIFO threshold selection */
 115 #define STM32_DMA_FIFO_THRESHOLD_1QUARTERFULL           0x00
 116 #define STM32_DMA_FIFO_THRESHOLD_HALFFULL               0x01
 117 #define STM32_DMA_FIFO_THRESHOLD_3QUARTERSFULL          0x02
 118 #define STM32_DMA_FIFO_THRESHOLD_FULL                   0x03
 119
 120 #define STM32_DMA_MAX_DATA_ITEMS        0xffff
 121 /*
 122  * Valid transfer starts from @0 to @0xFFFE leading to unaligned scatter
 123  * gather at boundary. Thus it's safer to round down this value on FIFO
 124  * size (16 Bytes)
 125  */
 126 #define STM32_DMA_ALIGNED_MAX_DATA_ITEMS        \
 127         ALIGN_DOWN(STM32_DMA_MAX_DATA_ITEMS, 16)
 128 #define STM32_DMA_MAX_CHANNELS          0x08
 129 #define STM32_DMA_MAX_REQUEST_ID        0x08
 130 #define STM32_DMA_MAX_DATA_PARAM        0x03
 131 #define STM32_DMA_FIFO_SIZE             16      /* FIFO is 16 bytes */
 132 #define STM32_DMA_MIN_BURST             4
 133 #define STM32_DMA_MAX_BURST             16
 134
 135 /* DMA Features */
 136 #define STM32_DMA_THRESHOLD_FTR_MASK    GENMASK(1, 0)
 137 #define STM32_DMA_THRESHOLD_FTR_GET(n)  ((n) & STM32_DMA_THRESHOLD_FTR_MASK)
 138
 139 enum stm32_dma_width {
 140         STM32_DMA_BYTE,
 141         STM32_DMA_HALF_WORD,
 142         STM32_DMA_WORD,
 143 };
 144
 145 enum stm32_dma_burst_size {
 146         STM32_DMA_BURST_SINGLE,
 147         STM32_DMA_BURST_INCR4,
 148         STM32_DMA_BURST_INCR8,
 149         STM32_DMA_BURST_INCR16,
 150 };
 151
 152 /**
 153  * struct stm32_dma_cfg - STM32 DMA custom configuration
 154  * @channel_id: channel ID
 155  * @request_line: DMA request
 156  * @stream_config: 32bit mask specifying the DMA channel configuration
 157  * @features: 32bit mask specifying the DMA Feature list
 158  */
 159 struct stm32_dma_cfg {
 160         u32 channel_id;
 161         u32 request_line;
 162         u32 stream_config;
 163         u32 features;
 164 };
 165
 166 struct stm32_dma_chan_reg {
 167         u32 dma_lisr;
 168         u32 dma_hisr;
 169         u32 dma_lifcr;
 170         u32 dma_hifcr;
 171         u32 dma_scr;
 172         u32 dma_sndtr;
 173         u32 dma_spar;
 174         u32 dma_sm0ar;
 175         u32 dma_sm1ar;
 176         u32 dma_sfcr;
 177 };
 178
 179 struct stm32_dma_sg_req {
 180         u32 len;
 181         struct stm32_dma_chan_reg chan_reg;
 182 };
 183
 184 struct stm32_dma_desc {
 185         struct virt_dma_desc vdesc;
 186         bool cyclic;
 187         u32 num_sgs;
 188         struct stm32_dma_sg_req sg_req[];
 189 };
 190
 191 struct stm32_dma_chan {
 192         struct virt_dma_chan vchan;
 193         bool config_init;
 194         bool busy;
 195         u32 id;
 196         u32 irq;
 197         struct stm32_dma_desc *desc;
 198         u32 next_sg;
 199         struct dma_slave_config dma_sconfig;
 200         struct stm32_dma_chan_reg chan_reg;
 201         u32 threshold;
 202         u32 mem_burst;
 203         u32 mem_width;
 204 };
 205
 206 struct stm32_dma_device {
 207         struct dma_device ddev;
 208         void __iomem *base;
 209         struct clk *clk;
 210         struct reset_control *rst;
 211         bool mem2mem;
 212         struct stm32_dma_chan chan[STM32_DMA_MAX_CHANNELS];
 213 };
 214
 215 static struct stm32_dma_device *stm32_dma_get_dev(struct stm32_dma_chan *chan)
 216 {
 217         return container_of(chan->vchan.chan.device, struct stm32_dma_device,
 218                             ddev);
 219 }
 220
 221 static struct stm32_dma_chan *to_stm32_dma_chan(struct dma_chan *c)
 222 {
 223         return container_of(c, struct stm32_dma_chan, vchan.chan);
 224 }
 225
 226 static struct stm32_dma_desc *to_stm32_dma_desc(struct virt_dma_desc *vdesc)
 227 {
 228         return container_of(vdesc, struct stm32_dma_desc, vdesc);
 229 }
 230
 231 static struct device *chan2dev(struct stm32_dma_chan *chan)
 232 {
 233         return &chan->vchan.chan.dev->device;
 234 }
 235
 236 static u32 stm32_dma_read(struct stm32_dma_device *dmadev, u32 reg)
 237 {
 238         return readl_relaxed(dmadev->base + reg);
 239 }
 240
 241 static void stm32_dma_write(struct stm32_dma_device *dmadev, u32 reg, u32 val)
 242 {
 243         writel_relaxed(val, dmadev->base + reg);
 244 }
 245
 246 static struct stm32_dma_desc *stm32_dma_alloc_desc(u32 num_sgs)
 247 {
 248         return kzalloc(sizeof(struct stm32_dma_desc) +
 249                        sizeof(struct stm32_dma_sg_req) * num_sgs, GFP_NOWAIT);
 250 }
 251
 252 static int stm32_dma_get_width(struct stm32_dma_chan *chan,
 253                                enum dma_slave_buswidth width)
 254 {
 255         switch (width) {
 256         case DMA_SLAVE_BUSWIDTH_1_BYTE:
 257                 return STM32_DMA_BYTE;
 258         case DMA_SLAVE_BUSWIDTH_2_BYTES:
 259                 return STM32_DMA_HALF_WORD;
 260         case DMA_SLAVE_BUSWIDTH_4_BYTES:
 261                 return STM32_DMA_WORD;
 262         default:
 263                 dev_err(chan2dev(chan), "Dma bus width not supported\n");
 264                 return -EINVAL;
 265         }
 266 }
 267
 268 static enum dma_slave_buswidth stm32_dma_get_max_width(u32 buf_len,
 269                                                        u32 threshold)
 270 {
 271         enum dma_slave_buswidth max_width;
 272
 273         if (threshold == STM32_DMA_FIFO_THRESHOLD_FULL)
 274                 max_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 275         else
 276                 max_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 277
 278         while ((buf_len < max_width  || buf_len % max_width) &&
 279                max_width > DMA_SLAVE_BUSWIDTH_1_BYTE)
 280                 max_width = max_width >> 1;
 281
 282         return max_width;
 283 }
 284
 285 static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold,
 286                                                 enum dma_slave_buswidth width)
 287 {
 288         u32 remaining;
 289
 290         if (width != DMA_SLAVE_BUSWIDTH_UNDEFINED) {
 291                 if (burst != 0) {
 292                         /*
 293                          * If number of beats fit in several whole bursts
 294                          * this configuration is allowed.
 295                          */
 296                         remaining = ((STM32_DMA_FIFO_SIZE / width) *
 297                                      (threshold + 1) / 4) % burst;
 298
 299                         if (remaining == 0)
 300                                 return true;
 301                 } else {
 302                         return true;
 303                 }
 304         }
 305
 306         return false;
 307 }
 308
 309 static bool stm32_dma_is_burst_possible(u32 buf_len, u32 threshold)
 310 {
 311         switch (threshold) {
 312         case STM32_DMA_FIFO_THRESHOLD_FULL:
 313                 if (buf_len >= STM32_DMA_MAX_BURST)
 314                         return true;
 315                 else
 316                         return false;
 317         case STM32_DMA_FIFO_THRESHOLD_HALFFULL:
 318                 if (buf_len >= STM32_DMA_MAX_BURST / 2)
 319                         return true;
 320                 else
 321                         return false;
 322         default:
 323                 return false;
 324         }
 325 }
 326
 327 static u32 stm32_dma_get_best_burst(u32 buf_len, u32 max_burst, u32 threshold,
 328                                     enum dma_slave_buswidth width)
 329 {
 330         u32 best_burst = max_burst;
 331
 332         if (best_burst == 1 || !stm32_dma_is_burst_possible(buf_len, threshold))
 333                 return 0;
 334
 335         while ((buf_len < best_burst * width && best_burst > 1) ||
 336                !stm32_dma_fifo_threshold_is_allowed(best_burst, threshold,
 337                                                     width)) {
 338                 if (best_burst > STM32_DMA_MIN_BURST)
 339                         best_burst = best_burst >> 1;
 340                 else
 341                         best_burst = 0;
 342         }
 343
 344         return best_burst;
 345 }
 346
 347 static int stm32_dma_get_burst(struct stm32_dma_chan *chan, u32 maxburst)
 348 {
 349         switch (maxburst) {
 350         case 0:
 351         case 1:
 352                 return STM32_DMA_BURST_SINGLE;
 353         case 4:
 354                 return STM32_DMA_BURST_INCR4;
 355         case 8:
 356                 return STM32_DMA_BURST_INCR8;
 357         case 16:
 358                 return STM32_DMA_BURST_INCR16;
 359         default:
 360                 dev_err(chan2dev(chan), "Dma burst size not supported\n");
 361                 return -EINVAL;
 362         }
 363 }
 364
 365 static void stm32_dma_set_fifo_config(struct stm32_dma_chan *chan,
 366                                       u32 src_burst, u32 dst_burst)
 367 {
 368         chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_MASK;
 369         chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_DMEIE;
 370
 371         if (!src_burst && !dst_burst) {
 372                 /* Using direct mode */
 373                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_DMEIE;
 374         } else {
 375                 /* Using FIFO mode */
 376                 chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
 377         }
 378 }
 379
 380 static int stm32_dma_slave_config(struct dma_chan *c,
 381                                   struct dma_slave_config *config)
 382 {
 383         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 384
 385         memcpy(&chan->dma_sconfig, config, sizeof(*config));
 386
 387         chan->config_init = true;
 388
 389         return 0;
 390 }
 391
 392 static u32 stm32_dma_irq_status(struct stm32_dma_chan *chan)
 393 {
 394         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 395         u32 flags, dma_isr;
 396
 397         /*
 398          * Read "flags" from DMA_xISR register corresponding to the selected
 399          * DMA channel at the correct bit offset inside that register.
 400          *
 401          * If (ch % 4) is 2 or 3, left shift the mask by 16 bits.
 402          * If (ch % 4) is 1 or 3, additionally left shift the mask by 6 bits.
 403          */
 404
 405         if (chan->id & 4)
 406                 dma_isr = stm32_dma_read(dmadev, STM32_DMA_HISR);
 407         else
 408                 dma_isr = stm32_dma_read(dmadev, STM32_DMA_LISR);
 409
 410         flags = dma_isr >> (((chan->id & 2) << 3) | ((chan->id & 1) * 6));
 411
 412         return flags & STM32_DMA_MASKI;
 413 }
 414
 415 static void stm32_dma_irq_clear(struct stm32_dma_chan *chan, u32 flags)
 416 {
 417         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 418         u32 dma_ifcr;
 419
 420         /*
 421          * Write "flags" to the DMA_xIFCR register corresponding to the selected
 422          * DMA channel at the correct bit offset inside that register.
 423          *
 424          * If (ch % 4) is 2 or 3, left shift the mask by 16 bits.
 425          * If (ch % 4) is 1 or 3, additionally left shift the mask by 6 bits.
 426          */
 427         flags &= STM32_DMA_MASKI;
 428         dma_ifcr = flags << (((chan->id & 2) << 3) | ((chan->id & 1) * 6));
 429
 430         if (chan->id & 4)
 431                 stm32_dma_write(dmadev, STM32_DMA_HIFCR, dma_ifcr);
 432         else
 433                 stm32_dma_write(dmadev, STM32_DMA_LIFCR, dma_ifcr);
 434 }
 435
 436 static int stm32_dma_disable_chan(struct stm32_dma_chan *chan)
 437 {
 438         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 439         unsigned long timeout = jiffies + msecs_to_jiffies(5000);
 440         u32 dma_scr, id;
 441
 442         id = chan->id;
 443         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 444
 445         if (dma_scr & STM32_DMA_SCR_EN) {
 446                 dma_scr &= ~STM32_DMA_SCR_EN;
 447                 stm32_dma_write(dmadev, STM32_DMA_SCR(id), dma_scr);
 448
 449                 do {
 450                         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 451                         dma_scr &= STM32_DMA_SCR_EN;
 452                         if (!dma_scr)
 453                                 break;
 454
 455                         if (time_after_eq(jiffies, timeout)) {
 456                                 dev_err(chan2dev(chan), "%s: timeout!\n",
 457                                         __func__);
 458                                 return -EBUSY;
 459                         }
 460                         cond_resched();
 461                 } while (1);
 462         }
 463
 464         return 0;
 465 }
 466
 467 static void stm32_dma_stop(struct stm32_dma_chan *chan)
 468 {
 469         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 470         u32 dma_scr, dma_sfcr, status;
 471         int ret;
 472
 473         /* Disable interrupts */
 474         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 475         dma_scr &= ~STM32_DMA_SCR_IRQ_MASK;
 476         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
 477         dma_sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 478         dma_sfcr &= ~STM32_DMA_SFCR_FEIE;
 479         stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), dma_sfcr);
 480
 481         /* Disable DMA */
 482         ret = stm32_dma_disable_chan(chan);
 483         if (ret < 0)
 484                 return;
 485
 486         /* Clear interrupt status if it is there */
 487         status = stm32_dma_irq_status(chan);
 488         if (status) {
 489                 dev_dbg(chan2dev(chan), "%s(): clearing interrupt: 0x%08x\n",
 490                         __func__, status);
 491                 stm32_dma_irq_clear(chan, status);
 492         }
 493
 494         chan->busy = false;
 495 }
 496
 497 static int stm32_dma_terminate_all(struct dma_chan *c)
 498 {
 499         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 500         unsigned long flags;
 501         LIST_HEAD(head);
 502
 503         spin_lock_irqsave(&chan->vchan.lock, flags);
 504
 505         if (chan->busy) {
 506                 stm32_dma_stop(chan);
 507                 chan->desc = NULL;
 508         }
 509
 510         vchan_get_all_descriptors(&chan->vchan, &head);
 511         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 512         vchan_dma_desc_free_list(&chan->vchan, &head);
 513
 514         return 0;
 515 }
 516
 517 static void stm32_dma_synchronize(struct dma_chan *c)
 518 {
 519         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 520
 521         vchan_synchronize(&chan->vchan);
 522 }
 523
 524 static void stm32_dma_dump_reg(struct stm32_dma_chan *chan)
 525 {
 526         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 527         u32 scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 528         u32 ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
 529         u32 spar = stm32_dma_read(dmadev, STM32_DMA_SPAR(chan->id));
 530         u32 sm0ar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(chan->id));
 531         u32 sm1ar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(chan->id));
 532         u32 sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 533
 534         dev_dbg(chan2dev(chan), "SCR:   0x%08x\n", scr);
 535         dev_dbg(chan2dev(chan), "NDTR:  0x%08x\n", ndtr);
 536         dev_dbg(chan2dev(chan), "SPAR:  0x%08x\n", spar);
 537         dev_dbg(chan2dev(chan), "SM0AR: 0x%08x\n", sm0ar);
 538         dev_dbg(chan2dev(chan), "SM1AR: 0x%08x\n", sm1ar);
 539         dev_dbg(chan2dev(chan), "SFCR:  0x%08x\n", sfcr);
 540 }
 541
 542 static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan);
 543
 544 static void stm32_dma_start_transfer(struct stm32_dma_chan *chan)
 545 {
 546         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 547         struct virt_dma_desc *vdesc;
 548         struct stm32_dma_sg_req *sg_req;
 549         struct stm32_dma_chan_reg *reg;
 550         u32 status;
 551         int ret;
 552
 553         ret = stm32_dma_disable_chan(chan);
 554         if (ret < 0)
 555                 return;
 556
 557         if (!chan->desc) {
 558                 vdesc = vchan_next_desc(&chan->vchan);
 559                 if (!vdesc)
 560                         return;
 561
 562                 chan->desc = to_stm32_dma_desc(vdesc);
 563                 chan->next_sg = 0;
 564         }
 565
 566         if (chan->next_sg == chan->desc->num_sgs)
 567                 chan->next_sg = 0;
 568
 569         sg_req = &chan->desc->sg_req[chan->next_sg];
 570         reg = &sg_req->chan_reg;
 571
 572         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
 573         stm32_dma_write(dmadev, STM32_DMA_SPAR(chan->id), reg->dma_spar);
 574         stm32_dma_write(dmadev, STM32_DMA_SM0AR(chan->id), reg->dma_sm0ar);
 575         stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), reg->dma_sfcr);
 576         stm32_dma_write(dmadev, STM32_DMA_SM1AR(chan->id), reg->dma_sm1ar);
 577         stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), reg->dma_sndtr);
 578
 579         chan->next_sg++;
 580
 581         /* Clear interrupt status if it is there */
 582         status = stm32_dma_irq_status(chan);
 583         if (status)
 584                 stm32_dma_irq_clear(chan, status);
 585
 586         if (chan->desc->cyclic)
 587                 stm32_dma_configure_next_sg(chan);
 588
 589         stm32_dma_dump_reg(chan);
 590
 591         /* Start DMA */
 592         reg->dma_scr |= STM32_DMA_SCR_EN;
 593         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
 594
 595         chan->busy = true;
 596
 597         dev_dbg(chan2dev(chan), "vchan %p: started\n", &chan->vchan);
 598 }
 599
 600 static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan)
 601 {
 602         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 603         struct stm32_dma_sg_req *sg_req;
 604         u32 dma_scr, dma_sm0ar, dma_sm1ar, id;
 605
 606         id = chan->id;
 607         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 608
 609         if (dma_scr & STM32_DMA_SCR_DBM) {
 610                 if (chan->next_sg == chan->desc->num_sgs)
 611                         chan->next_sg = 0;
 612
 613                 sg_req = &chan->desc->sg_req[chan->next_sg];
 614
 615                 if (dma_scr & STM32_DMA_SCR_CT) {
 616                         dma_sm0ar = sg_req->chan_reg.dma_sm0ar;
 617                         stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), dma_sm0ar);
 618                         dev_dbg(chan2dev(chan), "CT=1 <=> SM0AR: 0x%08x\n",
 619                                 stm32_dma_read(dmadev, STM32_DMA_SM0AR(id)));
 620                 } else {
 621                         dma_sm1ar = sg_req->chan_reg.dma_sm1ar;
 622                         stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), dma_sm1ar);
 623                         dev_dbg(chan2dev(chan), "CT=0 <=> SM1AR: 0x%08x\n",
 624                                 stm32_dma_read(dmadev, STM32_DMA_SM1AR(id)));
 625                 }
 626         }
 627 }
 628
 629 static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan)
 630 {
 631         if (chan->desc) {
 632                 if (chan->desc->cyclic) {
 633                         vchan_cyclic_callback(&chan->desc->vdesc);
 634                         chan->next_sg++;
 635                         stm32_dma_configure_next_sg(chan);
 636                 } else {
 637                         chan->busy = false;
 638                         if (chan->next_sg == chan->desc->num_sgs) {
 639                                 list_del(&chan->desc->vdesc.node);
 640                                 vchan_cookie_complete(&chan->desc->vdesc);
 641                                 chan->desc = NULL;
 642                         }
 643                         stm32_dma_start_transfer(chan);
 644                 }
 645         }
 646 }
 647
 648 static irqreturn_t stm32_dma_chan_irq(int irq, void *devid)
 649 {
 650         struct stm32_dma_chan *chan = devid;
 651         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 652         u32 status, scr;
 653
 654         spin_lock(&chan->vchan.lock);
 655
 656         status = stm32_dma_irq_status(chan);
 657         scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 658
 659         if (status & STM32_DMA_TCI) {
 660                 stm32_dma_irq_clear(chan, STM32_DMA_TCI);
 661                 if (scr & STM32_DMA_SCR_TCIE)
 662                         stm32_dma_handle_chan_done(chan);
 663                 status &= ~STM32_DMA_TCI;
 664         }
 665         if (status & STM32_DMA_HTI) {
 666                 stm32_dma_irq_clear(chan, STM32_DMA_HTI);
 667                 status &= ~STM32_DMA_HTI;
 668         }
 669         if (status & STM32_DMA_FEI) {
 670                 stm32_dma_irq_clear(chan, STM32_DMA_FEI);
 671                 status &= ~STM32_DMA_FEI;
 672                 if (!(scr & STM32_DMA_SCR_EN))
 673                         dev_err(chan2dev(chan), "FIFO Error\n");
 674                 else
 675                         dev_dbg(chan2dev(chan), "FIFO over/underrun\n");
 676         }
 677         if (status) {
 678                 stm32_dma_irq_clear(chan, status);
 679                 dev_err(chan2dev(chan), "DMA error: status=0x%08x\n", status);
 680                 if (!(scr & STM32_DMA_SCR_EN))
 681                         dev_err(chan2dev(chan), "chan disabled by HW\n");
 682         }
 683
 684         spin_unlock(&chan->vchan.lock);
 685
 686         return IRQ_HANDLED;
 687 }
 688
 689 static void stm32_dma_issue_pending(struct dma_chan *c)
 690 {
 691         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 692         unsigned long flags;
 693
 694         spin_lock_irqsave(&chan->vchan.lock, flags);
 695         if (vchan_issue_pending(&chan->vchan) && !chan->desc && !chan->busy) {
 696                 dev_dbg(chan2dev(chan), "vchan %p: issued\n", &chan->vchan);
 697                 stm32_dma_start_transfer(chan);
 698
 699         }
 700         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 701 }
 702
 703 static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
 704                                     enum dma_transfer_direction direction,
 705                                     enum dma_slave_buswidth *buswidth,
 706                                     u32 buf_len)
 707 {
 708         enum dma_slave_buswidth src_addr_width, dst_addr_width;
 709         int src_bus_width, dst_bus_width;
 710         int src_burst_size, dst_burst_size;
 711         u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst;
 712         u32 dma_scr, threshold;
 713
 714         src_addr_width = chan->dma_sconfig.src_addr_width;
 715         dst_addr_width = chan->dma_sconfig.dst_addr_width;
 716         src_maxburst = chan->dma_sconfig.src_maxburst;
 717         dst_maxburst = chan->dma_sconfig.dst_maxburst;
 718         threshold = chan->threshold;
 719
 720         switch (direction) {
 721         case DMA_MEM_TO_DEV:
 722                 /* Set device data size */
 723                 dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
 724                 if (dst_bus_width < 0)
 725                         return dst_bus_width;
 726
 727                 /* Set device burst size */
 728                 dst_best_burst = stm32_dma_get_best_burst(buf_len,
 729                                                           dst_maxburst,
 730                                                           threshold,
 731                                                           dst_addr_width);
 732
 733                 dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
 734                 if (dst_burst_size < 0)
 735                         return dst_burst_size;
 736
 737                 /* Set memory data size */
 738                 src_addr_width = stm32_dma_get_max_width(buf_len, threshold);
 739                 chan->mem_width = src_addr_width;
 740                 src_bus_width = stm32_dma_get_width(chan, src_addr_width);
 741                 if (src_bus_width < 0)
 742                         return src_bus_width;
 743
 744                 /* Set memory burst size */
 745                 src_maxburst = STM32_DMA_MAX_BURST;
 746                 src_best_burst = stm32_dma_get_best_burst(buf_len,
 747                                                           src_maxburst,
 748                                                           threshold,
 749                                                           src_addr_width);
 750                 src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
 751                 if (src_burst_size < 0)
 752                         return src_burst_size;
 753
 754                 dma_scr = STM32_DMA_SCR_DIR(STM32_DMA_MEM_TO_DEV) |
 755                         STM32_DMA_SCR_PSIZE(dst_bus_width) |
 756                         STM32_DMA_SCR_MSIZE(src_bus_width) |
 757                         STM32_DMA_SCR_PBURST(dst_burst_size) |
 758                         STM32_DMA_SCR_MBURST(src_burst_size);
 759
 760                 /* Set FIFO threshold */
 761                 chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
 762                 chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(threshold);
 763
 764                 /* Set peripheral address */
 765                 chan->chan_reg.dma_spar = chan->dma_sconfig.dst_addr;
 766                 *buswidth = dst_addr_width;
 767                 break;
 768
 769         case DMA_DEV_TO_MEM:
 770                 /* Set device data size */
 771                 src_bus_width = stm32_dma_get_width(chan, src_addr_width);
 772                 if (src_bus_width < 0)
 773                         return src_bus_width;
 774
 775                 /* Set device burst size */
 776                 src_best_burst = stm32_dma_get_best_burst(buf_len,
 777                                                           src_maxburst,
 778                                                           threshold,
 779                                                           src_addr_width);
 780                 chan->mem_burst = src_best_burst;
 781                 src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
 782                 if (src_burst_size < 0)
 783                         return src_burst_size;
 784
 785                 /* Set memory data size */
 786                 dst_addr_width = stm32_dma_get_max_width(buf_len, threshold);
 787                 chan->mem_width = dst_addr_width;
 788                 dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
 789                 if (dst_bus_width < 0)
 790                         return dst_bus_width;
 791
 792                 /* Set memory burst size */
 793                 dst_maxburst = STM32_DMA_MAX_BURST;
 794                 dst_best_burst = stm32_dma_get_best_burst(buf_len,
 795                                                           dst_maxburst,
 796                                                           threshold,
 797                                                           dst_addr_width);
 798                 chan->mem_burst = dst_best_burst;
 799                 dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
 800                 if (dst_burst_size < 0)
 801                         return dst_burst_size;
 802
 803                 dma_scr = STM32_DMA_SCR_DIR(STM32_DMA_DEV_TO_MEM) |
 804                         STM32_DMA_SCR_PSIZE(src_bus_width) |
 805                         STM32_DMA_SCR_MSIZE(dst_bus_width) |
 806                         STM32_DMA_SCR_PBURST(src_burst_size) |
 807                         STM32_DMA_SCR_MBURST(dst_burst_size);
 808
 809                 /* Set FIFO threshold */
 810                 chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
 811                 chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(threshold);
 812
 813                 /* Set peripheral address */
 814                 chan->chan_reg.dma_spar = chan->dma_sconfig.src_addr;
 815                 *buswidth = chan->dma_sconfig.src_addr_width;
 816                 break;
 817
 818         default:
 819                 dev_err(chan2dev(chan), "Dma direction is not supported\n");
 820                 return -EINVAL;
 821         }
 822
 823         stm32_dma_set_fifo_config(chan, src_best_burst, dst_best_burst);
 824
 825         /* Set DMA control register */
 826         chan->chan_reg.dma_scr &= ~(STM32_DMA_SCR_DIR_MASK |
 827                         STM32_DMA_SCR_PSIZE_MASK | STM32_DMA_SCR_MSIZE_MASK |
 828                         STM32_DMA_SCR_PBURST_MASK | STM32_DMA_SCR_MBURST_MASK);
 829         chan->chan_reg.dma_scr |= dma_scr;
 830
 831         return 0;
 832 }
 833
 834 static void stm32_dma_clear_reg(struct stm32_dma_chan_reg *regs)
 835 {
 836         memset(regs, 0, sizeof(struct stm32_dma_chan_reg));
 837 }
 838
 839 static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg(
 840         struct dma_chan *c, struct scatterlist *sgl,
 841         u32 sg_len, enum dma_transfer_direction direction,
 842         unsigned long flags, void *context)
 843 {
 844         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 845         struct stm32_dma_desc *desc;
 846         struct scatterlist *sg;
 847         enum dma_slave_buswidth buswidth;
 848         u32 nb_data_items;
 849         int i, ret;
 850
 851         if (!chan->config_init) {
 852                 dev_err(chan2dev(chan), "dma channel is not configured\n");
 853                 return NULL;
 854         }
 855
 856         if (sg_len < 1) {
 857                 dev_err(chan2dev(chan), "Invalid segment length %d\n", sg_len);
 858                 return NULL;
 859         }
 860
 861         desc = stm32_dma_alloc_desc(sg_len);
 862         if (!desc)
 863                 return NULL;
 864
 865         /* Set peripheral flow controller */
 866         if (chan->dma_sconfig.device_fc)
 867                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_PFCTRL;
 868         else
 869                 chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
 870
 871         for_each_sg(sgl, sg, sg_len, i) {
 872                 ret = stm32_dma_set_xfer_param(chan, direction, &buswidth,
 873                                                sg_dma_len(sg));
 874                 if (ret < 0)
 875                         goto err;
 876
 877                 desc->sg_req[i].len = sg_dma_len(sg);
 878
 879                 nb_data_items = desc->sg_req[i].len / buswidth;
 880                 if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) {
 881                         dev_err(chan2dev(chan), "nb items not supported\n");
 882                         goto err;
 883                 }
 884
 885                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
 886                 desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
 887                 desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
 888                 desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
 889                 desc->sg_req[i].chan_reg.dma_sm0ar = sg_dma_address(sg);
 890                 desc->sg_req[i].chan_reg.dma_sm1ar = sg_dma_address(sg);
 891                 desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
 892         }
 893
 894         desc->num_sgs = sg_len;
 895         desc->cyclic = false;
 896
 897         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 898
 899 err:
 900         kfree(desc);
 901         return NULL;
 902 }
 903
 904 static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic(
 905         struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
 906         size_t period_len, enum dma_transfer_direction direction,
 907         unsigned long flags)
 908 {
 909         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 910         struct stm32_dma_desc *desc;
 911         enum dma_slave_buswidth buswidth;
 912         u32 num_periods, nb_data_items;
 913         int i, ret;
 914
 915         if (!buf_len || !period_len) {
 916                 dev_err(chan2dev(chan), "Invalid buffer/period len\n");
 917                 return NULL;
 918         }
 919
 920         if (!chan->config_init) {
 921                 dev_err(chan2dev(chan), "dma channel is not configured\n");
 922                 return NULL;
 923         }
 924
 925         if (buf_len % period_len) {
 926                 dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
 927                 return NULL;
 928         }
 929
 930         /*
 931          * We allow to take more number of requests till DMA is
 932          * not started. The driver will loop over all requests.
 933          * Once DMA is started then new requests can be queued only after
 934          * terminating the DMA.
 935          */
 936         if (chan->busy) {
 937                 dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
 938                 return NULL;
 939         }
 940
 941         ret = stm32_dma_set_xfer_param(chan, direction, &buswidth, period_len);
 942         if (ret < 0)
 943                 return NULL;
 944
 945         nb_data_items = period_len / buswidth;
 946         if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) {
 947                 dev_err(chan2dev(chan), "number of items not supported\n");
 948                 return NULL;
 949         }
 950
 951         /*  Enable Circular mode or double buffer mode */
 952         if (buf_len == period_len)
 953                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_CIRC;
 954         else
 955                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_DBM;
 956
 957         /* Clear periph ctrl if client set it */
 958         chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
 959
 960         num_periods = buf_len / period_len;
 961
 962         desc = stm32_dma_alloc_desc(num_periods);
 963         if (!desc)
 964                 return NULL;
 965
 966         for (i = 0; i < num_periods; i++) {
 967                 desc->sg_req[i].len = period_len;
 968
 969                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
 970                 desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
 971                 desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
 972                 desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
 973                 desc->sg_req[i].chan_reg.dma_sm0ar = buf_addr;
 974                 desc->sg_req[i].chan_reg.dma_sm1ar = buf_addr;
 975                 desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
 976                 buf_addr += period_len;
 977         }
 978
 979         desc->num_sgs = num_periods;
 980         desc->cyclic = true;
 981
 982         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 983 }
 984
 985 static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy(
 986         struct dma_chan *c, dma_addr_t dest,
 987         dma_addr_t src, size_t len, unsigned long flags)
 988 {
 989         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 990         enum dma_slave_buswidth max_width;
 991         struct stm32_dma_desc *desc;
 992         size_t xfer_count, offset;
 993         u32 num_sgs, best_burst, dma_burst, threshold;
 994         int i;
 995
 996         num_sgs = DIV_ROUND_UP(len, STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
 997         desc = stm32_dma_alloc_desc(num_sgs);
 998         if (!desc)
 999                 return NULL;
1000
1001         threshold = chan->threshold;
1002
1003         for (offset = 0, i = 0; offset < len; offset += xfer_count, i++) {
1004                 xfer_count = min_t(size_t, len - offset,
1005                                    STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
1006
1007                 /* Compute best burst size */
1008                 max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1009                 best_burst = stm32_dma_get_best_burst(len, STM32_DMA_MAX_BURST,
1010                                                       threshold, max_width);
1011                 dma_burst = stm32_dma_get_burst(chan, best_burst);
1012
1013                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
1014                 desc->sg_req[i].chan_reg.dma_scr =
1015                         STM32_DMA_SCR_DIR(STM32_DMA_MEM_TO_MEM) |
1016                         STM32_DMA_SCR_PBURST(dma_burst) |
1017                         STM32_DMA_SCR_MBURST(dma_burst) |
1018                         STM32_DMA_SCR_MINC |
1019                         STM32_DMA_SCR_PINC |
1020                         STM32_DMA_SCR_TCIE |
1021                         STM32_DMA_SCR_TEIE;
1022                 desc->sg_req[i].chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
1023                 desc->sg_req[i].chan_reg.dma_sfcr |=
1024                         STM32_DMA_SFCR_FTH(threshold);
1025                 desc->sg_req[i].chan_reg.dma_spar = src + offset;
1026                 desc->sg_req[i].chan_reg.dma_sm0ar = dest + offset;
1027                 desc->sg_req[i].chan_reg.dma_sndtr = xfer_count;
1028                 desc->sg_req[i].len = xfer_count;
1029         }
1030
1031         desc->num_sgs = num_sgs;
1032         desc->cyclic = false;
1033
1034         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
1035 }
1036
1037 static u32 stm32_dma_get_remaining_bytes(struct stm32_dma_chan *chan)
1038 {
1039         u32 dma_scr, width, ndtr;
1040         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1041
1042         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
1043         width = STM32_DMA_SCR_PSIZE_GET(dma_scr);
1044         ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
1045
1046         return ndtr << width;
1047 }
1048
1049 static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan,
1050                                      struct stm32_dma_desc *desc,
1051                                      u32 next_sg)
1052 {
1053         u32 modulo, burst_size;
1054         u32 residue = 0;
1055         int i;
1056
1057         /*
1058          * In cyclic mode, for the last period, residue = remaining bytes from
1059          * NDTR
1060          */
1061         if (chan->desc->cyclic && next_sg == 0) {
1062                 residue = stm32_dma_get_remaining_bytes(chan);
1063                 goto end;
1064         }
1065
1066         /*
1067          * For all other periods in cyclic mode, and in sg mode,
1068          * residue = remaining bytes from NDTR + remaining periods/sg to be
1069          * transferred
1070          */
1071         for (i = next_sg; i < desc->num_sgs; i++)
1072                 residue += desc->sg_req[i].len;
1073         residue += stm32_dma_get_remaining_bytes(chan);
1074
1075 end:
1076         if (!chan->mem_burst)
1077                 return residue;
1078
1079         burst_size = chan->mem_burst * chan->mem_width;
1080         modulo = residue % burst_size;
1081         if (modulo)
1082                 residue = residue - modulo + burst_size;
1083
1084         return residue;
1085 }
1086
1087 static enum dma_status stm32_dma_tx_status(struct dma_chan *c,
1088                                            dma_cookie_t cookie,
1089                                            struct dma_tx_state *state)
1090 {
1091         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1092         struct virt_dma_desc *vdesc;
1093         enum dma_status status;
1094         unsigned long flags;
1095         u32 residue = 0;
1096
1097         status = dma_cookie_status(c, cookie, state);
1098         if (status == DMA_COMPLETE || !state)
1099                 return status;
1100
1101         spin_lock_irqsave(&chan->vchan.lock, flags);
1102         vdesc = vchan_find_desc(&chan->vchan, cookie);
1103         if (chan->desc && cookie == chan->desc->vdesc.tx.cookie)
1104                 residue = stm32_dma_desc_residue(chan, chan->desc,
1105                                                  chan->next_sg);
1106         else if (vdesc)
1107                 residue = stm32_dma_desc_residue(chan,
1108                                                  to_stm32_dma_desc(vdesc), 0);
1109         dma_set_residue(state, residue);
1110
1111         spin_unlock_irqrestore(&chan->vchan.lock, flags);
1112
1113         return status;
1114 }
1115
1116 static int stm32_dma_alloc_chan_resources(struct dma_chan *c)
1117 {
1118         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1119         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1120         int ret;
1121
1122         chan->config_init = false;
1123         ret = clk_prepare_enable(dmadev->clk);
1124         if (ret < 0) {
1125                 dev_err(chan2dev(chan), "clk_prepare_enable failed: %d\n", ret);
1126                 return ret;
1127         }
1128
1129         ret = stm32_dma_disable_chan(chan);
1130         if (ret < 0)
1131                 clk_disable_unprepare(dmadev->clk);
1132
1133         return ret;
1134 }
1135
1136 static void stm32_dma_free_chan_resources(struct dma_chan *c)
1137 {
1138         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1139         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1140         unsigned long flags;
1141
1142         dev_dbg(chan2dev(chan), "Freeing channel %d\n", chan->id);
1143
1144         if (chan->busy) {
1145                 spin_lock_irqsave(&chan->vchan.lock, flags);
1146                 stm32_dma_stop(chan);
1147                 chan->desc = NULL;
1148                 spin_unlock_irqrestore(&chan->vchan.lock, flags);
1149         }
1150
1151         clk_disable_unprepare(dmadev->clk);
1152
1153         vchan_free_chan_resources(to_virt_chan(c));
1154 }
1155
1156 static void stm32_dma_desc_free(struct virt_dma_desc *vdesc)
1157 {
1158         kfree(container_of(vdesc, struct stm32_dma_desc, vdesc));
1159 }
1160
1161 static void stm32_dma_set_config(struct stm32_dma_chan *chan,
1162                                  struct stm32_dma_cfg *cfg)
1163 {
1164         stm32_dma_clear_reg(&chan->chan_reg);
1165
1166         chan->chan_reg.dma_scr = cfg->stream_config & STM32_DMA_SCR_CFG_MASK;
1167         chan->chan_reg.dma_scr |= STM32_DMA_SCR_REQ(cfg->request_line);
1168
1169         /* Enable Interrupts  */
1170         chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE;
1171
1172         chan->threshold = STM32_DMA_THRESHOLD_FTR_GET(cfg->features);
1173 }
1174
1175 static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec,
1176                                            struct of_dma *ofdma)
1177 {
1178         struct stm32_dma_device *dmadev = ofdma->of_dma_data;
1179         struct device *dev = dmadev->ddev.dev;
1180         struct stm32_dma_cfg cfg;
1181         struct stm32_dma_chan *chan;
1182         struct dma_chan *c;
1183
1184         if (dma_spec->args_count < 4) {
1185                 dev_err(dev, "Bad number of cells\n");
1186                 return NULL;
1187         }
1188
1189         cfg.channel_id = dma_spec->args[0];
1190         cfg.request_line = dma_spec->args[1];
1191         cfg.stream_config = dma_spec->args[2];
1192         cfg.features = dma_spec->args[3];
1193
1194         if (cfg.channel_id >= STM32_DMA_MAX_CHANNELS ||
1195             cfg.request_line >= STM32_DMA_MAX_REQUEST_ID) {
1196                 dev_err(dev, "Bad channel and/or request id\n");
1197                 return NULL;
1198         }
1199
1200         chan = &dmadev->chan[cfg.channel_id];
1201
1202         c = dma_get_slave_channel(&chan->vchan.chan);
1203         if (!c) {
1204                 dev_err(dev, "No more channels available\n");
1205                 return NULL;
1206         }
1207
1208         stm32_dma_set_config(chan, &cfg);
1209
1210         return c;
1211 }
1212
1213 static const struct of_device_id stm32_dma_of_match[] = {
1214         { .compatible = "st,stm32-dma", },
1215         { /* sentinel */ },
1216 };
1217 MODULE_DEVICE_TABLE(of, stm32_dma_of_match);
1218
1219 static int stm32_dma_probe(struct platform_device *pdev)
1220 {
1221         struct stm32_dma_chan *chan;
1222         struct stm32_dma_device *dmadev;
1223         struct dma_device *dd;
1224         const struct of_device_id *match;
1225         struct resource *res;
1226         int i, ret;
1227
1228         match = of_match_device(stm32_dma_of_match, &pdev->dev);
1229         if (!match) {
1230                 dev_err(&pdev->dev, "Error: No device match found\n");
1231                 return -ENODEV;
1232         }
1233
1234         dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
1235         if (!dmadev)
1236                 return -ENOMEM;
1237
1238         dd = &dmadev->ddev;
1239
1240         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1241         dmadev->base = devm_ioremap_resource(&pdev->dev, res);
1242         if (IS_ERR(dmadev->base))
1243                 return PTR_ERR(dmadev->base);
1244
1245         dmadev->clk = devm_clk_get(&pdev->dev, NULL);
1246         if (IS_ERR(dmadev->clk)) {
1247                 dev_err(&pdev->dev, "Error: Missing controller clock\n");
1248                 return PTR_ERR(dmadev->clk);
1249         }
1250
1251         dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node,
1252                                                 "st,mem2mem");
1253
1254         dmadev->rst = devm_reset_control_get(&pdev->dev, NULL);
1255         if (!IS_ERR(dmadev->rst)) {
1256                 reset_control_assert(dmadev->rst);
1257                 udelay(2);
1258                 reset_control_deassert(dmadev->rst);
1259         }
1260
1261         dma_cap_set(DMA_SLAVE, dd->cap_mask);
1262         dma_cap_set(DMA_PRIVATE, dd->cap_mask);
1263         dma_cap_set(DMA_CYCLIC, dd->cap_mask);
1264         dd->device_alloc_chan_resources = stm32_dma_alloc_chan_resources;
1265         dd->device_free_chan_resources = stm32_dma_free_chan_resources;
1266         dd->device_tx_status = stm32_dma_tx_status;
1267         dd->device_issue_pending = stm32_dma_issue_pending;
1268         dd->device_prep_slave_sg = stm32_dma_prep_slave_sg;
1269         dd->device_prep_dma_cyclic = stm32_dma_prep_dma_cyclic;
1270         dd->device_config = stm32_dma_slave_config;
1271         dd->device_terminate_all = stm32_dma_terminate_all;
1272         dd->device_synchronize = stm32_dma_synchronize;
1273         dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1274                 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1275                 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1276         dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1277                 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1278                 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1279         dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1280         dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
1281         dd->max_burst = STM32_DMA_MAX_BURST;
1282         dd->dev = &pdev->dev;
1283         INIT_LIST_HEAD(&dd->channels);
1284
1285         if (dmadev->mem2mem) {
1286                 dma_cap_set(DMA_MEMCPY, dd->cap_mask);
1287                 dd->device_prep_dma_memcpy = stm32_dma_prep_dma_memcpy;
1288                 dd->directions |= BIT(DMA_MEM_TO_MEM);
1289         }
1290
1291         for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
1292                 chan = &dmadev->chan[i];
1293                 chan->id = i;
1294                 chan->vchan.desc_free = stm32_dma_desc_free;
1295                 vchan_init(&chan->vchan, dd);
1296         }
1297
1298         ret = dma_async_device_register(dd);
1299         if (ret)
1300                 return ret;
1301
1302         for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
1303                 chan = &dmadev->chan[i];
1304                 res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
1305                 if (!res) {
1306                         ret = -EINVAL;
1307                         dev_err(&pdev->dev, "No irq resource for chan %d\n", i);
1308                         goto err_unregister;
1309                 }
1310                 chan->irq = res->start;
1311                 ret = devm_request_irq(&pdev->dev, chan->irq,
1312                                        stm32_dma_chan_irq, 0,
1313                                        dev_name(chan2dev(chan)), chan);
1314                 if (ret) {
1315                         dev_err(&pdev->dev,
1316                                 "request_irq failed with err %d channel %d\n",
1317                                 ret, i);
1318                         goto err_unregister;
1319                 }
1320         }
1321
1322         ret = of_dma_controller_register(pdev->dev.of_node,
1323                                          stm32_dma_of_xlate, dmadev);
1324         if (ret < 0) {
1325                 dev_err(&pdev->dev,
1326                         "STM32 DMA DMA OF registration failed %d\n", ret);
1327                 goto err_unregister;
1328         }
1329
1330         platform_set_drvdata(pdev, dmadev);
1331
1332         dev_info(&pdev->dev, "STM32 DMA driver registered\n");
1333
1334         return 0;
1335
1336 err_unregister:
1337         dma_async_device_unregister(dd);
1338
1339         return ret;
1340 }
1341
1342 static struct platform_driver stm32_dma_driver = {
1343         .driver = {
1344                 .name = "stm32-dma",
1345                 .of_match_table = stm32_dma_of_match,
1346         },
1347 };
1348
1349 static int __init stm32_dma_init(void)
1350 {
1351         return platform_driver_probe(&stm32_dma_driver, stm32_dma_probe);
1352 }
1353 subsys_initcall(stm32_dma_init);