drivers/nvmem/vf610-ocotp.c

   1 /*
   2  * Copyright (C) 2015 Toradex AG.
   3  *
   4  * Author: Sanchayan Maity <[email protected]>
   5  *
   6  * Based on the barebox ocotp driver,
   7  * Copyright (c) 2010 Baruch Siach <[email protected]>
   8  *      Orex Computed Radiography
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 and
  12  * only version 2 as published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #include <linux/clk.h>
  21 #include <linux/delay.h>
  22 #include <linux/device.h>
  23 #include <linux/io.h>
  24 #include <linux/module.h>
  25 #include <linux/nvmem-provider.h>
  26 #include <linux/of.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/slab.h>
  29
  30 /* OCOTP Register Offsets */
  31 #define OCOTP_CTRL_REG                          0x00
  32 #define OCOTP_CTRL_SET                          0x04
  33 #define OCOTP_CTRL_CLR                          0x08
  34 #define OCOTP_TIMING                            0x10
  35 #define OCOTP_DATA                              0x20
  36 #define OCOTP_READ_CTRL_REG                     0x30
  37 #define OCOTP_READ_FUSE_DATA                    0x40
  38
  39 /* OCOTP Register bits and masks */
  40 #define OCOTP_CTRL_WR_UNLOCK                    16
  41 #define OCOTP_CTRL_WR_UNLOCK_KEY                0x3E77
  42 #define OCOTP_CTRL_WR_UNLOCK_MASK               GENMASK(31, 16)
  43 #define OCOTP_CTRL_ADDR                         0
  44 #define OCOTP_CTRL_ADDR_MASK                    GENMASK(6, 0)
  45 #define OCOTP_CTRL_RELOAD_SHADOWS               BIT(10)
  46 #define OCOTP_CTRL_ERR                          BIT(9)
  47 #define OCOTP_CTRL_BUSY                         BIT(8)
  48
  49 #define OCOTP_TIMING_STROBE_READ                16
  50 #define OCOTP_TIMING_STROBE_READ_MASK           GENMASK(21, 16)
  51 #define OCOTP_TIMING_RELAX                      12
  52 #define OCOTP_TIMING_RELAX_MASK                 GENMASK(15, 12)
  53 #define OCOTP_TIMING_STROBE_PROG                0
  54 #define OCOTP_TIMING_STROBE_PROG_MASK           GENMASK(11, 0)
  55
  56 #define OCOTP_READ_CTRL_READ_FUSE               0x1
  57
  58 #define VF610_OCOTP_TIMEOUT                     100000
  59
  60 #define BF(value, field)                (((value) << field) & field##_MASK)
  61
  62 #define DEF_RELAX                               20
  63
  64 static const int base_to_fuse_addr_mappings[][2] = {
  65         {0x400, 0x00},
  66         {0x410, 0x01},
  67         {0x420, 0x02},
  68         {0x450, 0x05},
  69         {0x4F0, 0x0F},
  70         {0x600, 0x20},
  71         {0x610, 0x21},
  72         {0x620, 0x22},
  73         {0x630, 0x23},
  74         {0x640, 0x24},
  75         {0x650, 0x25},
  76         {0x660, 0x26},
  77         {0x670, 0x27},
  78         {0x6F0, 0x2F},
  79         {0x880, 0x38},
  80         {0x890, 0x39},
  81         {0x8A0, 0x3A},
  82         {0x8B0, 0x3B},
  83         {0x8C0, 0x3C},
  84         {0x8D0, 0x3D},
  85         {0x8E0, 0x3E},
  86         {0x8F0, 0x3F},
  87         {0xC80, 0x78},
  88         {0xC90, 0x79},
  89         {0xCA0, 0x7A},
  90         {0xCB0, 0x7B},
  91         {0xCC0, 0x7C},
  92         {0xCD0, 0x7D},
  93         {0xCE0, 0x7E},
  94         {0xCF0, 0x7F},
  95 };
  96
  97 struct vf610_ocotp {
  98         void __iomem *base;
  99         struct clk *clk;
 100         struct device *dev;
 101         struct nvmem_device *nvmem;
 102         int timing;
 103 };
 104
 105 static int vf610_ocotp_wait_busy(void __iomem *base)
 106 {
 107         int timeout = VF610_OCOTP_TIMEOUT;
 108
 109         while ((readl(base) & OCOTP_CTRL_BUSY) && --timeout)
 110                 udelay(10);
 111
 112         if (!timeout) {
 113                 writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR);
 114                 return -ETIMEDOUT;
 115         }
 116
 117         udelay(10);
 118
 119         return 0;
 120 }
 121
 122 static int vf610_ocotp_calculate_timing(struct vf610_ocotp *ocotp_dev)
 123 {
 124         u32 clk_rate;
 125         u32 relax, strobe_read, strobe_prog;
 126         u32 timing;
 127
 128         clk_rate = clk_get_rate(ocotp_dev->clk);
 129
 130         /* Refer section OTP read/write timing parameters in TRM */
 131         relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
 132         strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
 133         strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;
 134
 135         timing = BF(relax, OCOTP_TIMING_RELAX);
 136         timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ);
 137         timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG);
 138
 139         return timing;
 140 }
 141
 142 static int vf610_get_fuse_address(int base_addr_offset)
 143 {
 144         int i;
 145
 146         for (i = 0; i < ARRAY_SIZE(base_to_fuse_addr_mappings); i++) {
 147                 if (base_to_fuse_addr_mappings[i][0] == base_addr_offset)
 148                         return base_to_fuse_addr_mappings[i][1];
 149         }
 150
 151         return -EINVAL;
 152 }
 153
 154 static int vf610_ocotp_read(void *context, unsigned int offset,
 155                         void *val, size_t bytes)
 156 {
 157         struct vf610_ocotp *ocotp = context;
 158         void __iomem *base = ocotp->base;
 159         u32 reg, *buf = val;
 160         int fuse_addr;
 161         int ret;
 162
 163         while (bytes > 0) {
 164                 fuse_addr = vf610_get_fuse_address(offset);
 165                 if (fuse_addr > 0) {
 166                         writel(ocotp->timing, base + OCOTP_TIMING);
 167                         ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG);
 168                         if (ret)
 169                                 return ret;
 170
 171                         reg = readl(base + OCOTP_CTRL_REG);
 172                         reg &= ~OCOTP_CTRL_ADDR_MASK;
 173                         reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
 174                         reg |= BF(fuse_addr, OCOTP_CTRL_ADDR);
 175                         writel(reg, base + OCOTP_CTRL_REG);
 176
 177                         writel(OCOTP_READ_CTRL_READ_FUSE,
 178                                 base + OCOTP_READ_CTRL_REG);
 179                         ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG);
 180                         if (ret)
 181                                 return ret;
 182
 183                         if (readl(base) & OCOTP_CTRL_ERR) {
 184                                 dev_dbg(ocotp->dev, "Error reading from fuse address %x\n",
 185                                         fuse_addr);
 186                                 writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR);
 187                         }
 188
 189                         /*
 190                          * In case of error, we do not abort and expect to read
 191                          * 0xBADABADA as mentioned by the TRM. We just read this
 192                          * value and return.
 193                          */
 194                         *buf = readl(base + OCOTP_READ_FUSE_DATA);
 195                 } else {
 196                         *buf = 0;
 197                 }
 198
 199                 buf++;
 200                 bytes -= 4;
 201                 offset += 4;
 202         }
 203
 204         return 0;
 205 }
 206
 207 static struct nvmem_config ocotp_config = {
 208         .name = "ocotp",
 209         .stride = 4,
 210         .word_size = 4,
 211         .reg_read = vf610_ocotp_read,
 212 };
 213
 214 static const struct of_device_id ocotp_of_match[] = {
 215         { .compatible = "fsl,vf610-ocotp", },
 216         {/* sentinel */},
 217 };
 218 MODULE_DEVICE_TABLE(of, ocotp_of_match);
 219
 220 static int vf610_ocotp_probe(struct platform_device *pdev)
 221 {
 222         struct device *dev = &pdev->dev;
 223         struct resource *res;
 224         struct vf610_ocotp *ocotp_dev;
 225
 226         ocotp_dev = devm_kzalloc(dev, sizeof(struct vf610_ocotp), GFP_KERNEL);
 227         if (!ocotp_dev)
 228                 return -ENOMEM;
 229
 230         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 231         ocotp_dev->base = devm_ioremap_resource(dev, res);
 232         if (IS_ERR(ocotp_dev->base))
 233                 return PTR_ERR(ocotp_dev->base);
 234
 235         ocotp_dev->clk = devm_clk_get(dev, NULL);
 236         if (IS_ERR(ocotp_dev->clk)) {
 237                 dev_err(dev, "failed getting clock, err = %ld\n",
 238                         PTR_ERR(ocotp_dev->clk));
 239                 return PTR_ERR(ocotp_dev->clk);
 240         }
 241         ocotp_dev->dev = dev;
 242         ocotp_dev->timing = vf610_ocotp_calculate_timing(ocotp_dev);
 243
 244         ocotp_config.size = resource_size(res);
 245         ocotp_config.priv = ocotp_dev;
 246         ocotp_config.dev = dev;
 247
 248         ocotp_dev->nvmem = devm_nvmem_register(dev, &ocotp_config);
 249
 250         return PTR_ERR_OR_ZERO(ocotp_dev->nvmem);
 251 }
 252
 253 static struct platform_driver vf610_ocotp_driver = {
 254         .probe = vf610_ocotp_probe,
 255         .driver = {
 256                 .name = "vf610-ocotp",
 257                 .of_match_table = ocotp_of_match,
 258         },
 259 };
 260 module_platform_driver(vf610_ocotp_driver);
 261 MODULE_AUTHOR("Sanchayan Maity <[email protected]>");
 262 MODULE_DESCRIPTION("Vybrid OCOTP driver");
 263 MODULE_LICENSE("GPL v2");