drivers/nvmem/vf610-ocotp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2015 Toradex AG.
   4  *
   5  * Author: Sanchayan Maity <sanchayan.maity@toradex.com>
   6  *
   7  * Based on the barebox ocotp driver,
   8  * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>
   9  *      Orex Computed Radiography
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/delay.h>
  14 #include <linux/device.h>
  15 #include <linux/io.h>
  16 #include <linux/module.h>
  17 #include <linux/nvmem-provider.h>
  18 #include <linux/of.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/slab.h>
  21
  22 /* OCOTP Register Offsets */
  23 #define OCOTP_CTRL_REG                          0x00
  24 #define OCOTP_CTRL_SET                          0x04
  25 #define OCOTP_CTRL_CLR                          0x08
  26 #define OCOTP_TIMING                            0x10
  27 #define OCOTP_DATA                              0x20
  28 #define OCOTP_READ_CTRL_REG                     0x30
  29 #define OCOTP_READ_FUSE_DATA                    0x40
  30
  31 /* OCOTP Register bits and masks */
  32 #define OCOTP_CTRL_WR_UNLOCK                    16
  33 #define OCOTP_CTRL_WR_UNLOCK_KEY                0x3E77
  34 #define OCOTP_CTRL_WR_UNLOCK_MASK               GENMASK(31, 16)
  35 #define OCOTP_CTRL_ADDR                         0
  36 #define OCOTP_CTRL_ADDR_MASK                    GENMASK(6, 0)
  37 #define OCOTP_CTRL_RELOAD_SHADOWS               BIT(10)
  38 #define OCOTP_CTRL_ERR                          BIT(9)
  39 #define OCOTP_CTRL_BUSY                         BIT(8)
  40
  41 #define OCOTP_TIMING_STROBE_READ                16
  42 #define OCOTP_TIMING_STROBE_READ_MASK           GENMASK(21, 16)
  43 #define OCOTP_TIMING_RELAX                      12
  44 #define OCOTP_TIMING_RELAX_MASK                 GENMASK(15, 12)
  45 #define OCOTP_TIMING_STROBE_PROG                0
  46 #define OCOTP_TIMING_STROBE_PROG_MASK           GENMASK(11, 0)
  47
  48 #define OCOTP_READ_CTRL_READ_FUSE               0x1
  49
  50 #define VF610_OCOTP_TIMEOUT                     100000
  51
  52 #define BF(value, field)                (((value) << field) & field##_MASK)
  53
  54 #define DEF_RELAX                               20
  55
  56 static const int base_to_fuse_addr_mappings[][2] = {
  57         {0x400, 0x00},
  58         {0x410, 0x01},
  59         {0x420, 0x02},
  60         {0x450, 0x05},
  61         {0x4F0, 0x0F},
  62         {0x600, 0x20},
  63         {0x610, 0x21},
  64         {0x620, 0x22},
  65         {0x630, 0x23},
  66         {0x640, 0x24},
  67         {0x650, 0x25},
  68         {0x660, 0x26},
  69         {0x670, 0x27},
  70         {0x6F0, 0x2F},
  71         {0x880, 0x38},
  72         {0x890, 0x39},
  73         {0x8A0, 0x3A},
  74         {0x8B0, 0x3B},
  75         {0x8C0, 0x3C},
  76         {0x8D0, 0x3D},
  77         {0x8E0, 0x3E},
  78         {0x8F0, 0x3F},
  79         {0xC80, 0x78},
  80         {0xC90, 0x79},
  81         {0xCA0, 0x7A},
  82         {0xCB0, 0x7B},
  83         {0xCC0, 0x7C},
  84         {0xCD0, 0x7D},
  85         {0xCE0, 0x7E},
  86         {0xCF0, 0x7F},
  87 };
  88
  89 struct vf610_ocotp {
  90         void __iomem *base;
  91         struct clk *clk;
  92         struct device *dev;
  93         struct nvmem_device *nvmem;
  94         int timing;
  95 };
  96
  97 static int vf610_ocotp_wait_busy(void __iomem *base)
  98 {
  99         int timeout = VF610_OCOTP_TIMEOUT;
 100
 101         while ((readl(base) & OCOTP_CTRL_BUSY) && --timeout)
 102                 udelay(10);
 103
 104         if (!timeout) {
 105                 writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR);
 106                 return -ETIMEDOUT;
 107         }
 108
 109         udelay(10);
 110
 111         return 0;
 112 }
 113
 114 static int vf610_ocotp_calculate_timing(struct vf610_ocotp *ocotp_dev)
 115 {
 116         u32 clk_rate;
 117         u32 relax, strobe_read, strobe_prog;
 118         u32 timing;
 119
 120         clk_rate = clk_get_rate(ocotp_dev->clk);
 121
 122         /* Refer section OTP read/write timing parameters in TRM */
 123         relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
 124         strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
 125         strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;
 126
 127         timing = BF(relax, OCOTP_TIMING_RELAX);
 128         timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ);
 129         timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG);
 130
 131         return timing;
 132 }
 133
 134 static int vf610_get_fuse_address(int base_addr_offset)
 135 {
 136         int i;
 137
 138         for (i = 0; i < ARRAY_SIZE(base_to_fuse_addr_mappings); i++) {
 139                 if (base_to_fuse_addr_mappings[i][0] == base_addr_offset)
 140                         return base_to_fuse_addr_mappings[i][1];
 141         }
 142
 143         return -EINVAL;
 144 }
 145
 146 static int vf610_ocotp_read(void *context, unsigned int offset,
 147                         void *val, size_t bytes)
 148 {
 149         struct vf610_ocotp *ocotp = context;
 150         void __iomem *base = ocotp->base;
 151         u32 reg, *buf = val;
 152         int fuse_addr;
 153         int ret;
 154
 155         while (bytes > 0) {
 156                 fuse_addr = vf610_get_fuse_address(offset);
 157                 if (fuse_addr > 0) {
 158                         writel(ocotp->timing, base + OCOTP_TIMING);
 159                         ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG);
 160                         if (ret)
 161                                 return ret;
 162
 163                         reg = readl(base + OCOTP_CTRL_REG);
 164                         reg &= ~OCOTP_CTRL_ADDR_MASK;
 165                         reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
 166                         reg |= BF(fuse_addr, OCOTP_CTRL_ADDR);
 167                         writel(reg, base + OCOTP_CTRL_REG);
 168
 169                         writel(OCOTP_READ_CTRL_READ_FUSE,
 170                                 base + OCOTP_READ_CTRL_REG);
 171                         ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG);
 172                         if (ret)
 173                                 return ret;
 174
 175                         if (readl(base) & OCOTP_CTRL_ERR) {
 176                                 dev_dbg(ocotp->dev, "Error reading from fuse address %x\n",
 177                                         fuse_addr);
 178                                 writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR);
 179                         }
 180
 181                         /*
 182                          * In case of error, we do not abort and expect to read
 183                          * 0xBADABADA as mentioned by the TRM. We just read this
 184                          * value and return.
 185                          */
 186                         *buf = readl(base + OCOTP_READ_FUSE_DATA);
 187                 } else {
 188                         *buf = 0;
 189                 }
 190
 191                 buf++;
 192                 bytes -= 4;
 193                 offset += 4;
 194         }
 195
 196         return 0;
 197 }
 198
 199 static struct nvmem_config ocotp_config = {
 200         .name = "ocotp",
 201         .stride = 4,
 202         .word_size = 4,
 203         .reg_read = vf610_ocotp_read,
 204 };
 205
 206 static const struct of_device_id ocotp_of_match[] = {
 207         { .compatible = "fsl,vf610-ocotp", },
 208         {/* sentinel */},
 209 };
 210 MODULE_DEVICE_TABLE(of, ocotp_of_match);
 211
 212 static int vf610_ocotp_probe(struct platform_device *pdev)
 213 {
 214         struct device *dev = &pdev->dev;
 215         struct resource *res;
 216         struct vf610_ocotp *ocotp_dev;
 217
 218         ocotp_dev = devm_kzalloc(dev, sizeof(struct vf610_ocotp), GFP_KERNEL);
 219         if (!ocotp_dev)
 220                 return -ENOMEM;
 221
 222         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 223         ocotp_dev->base = devm_ioremap_resource(dev, res);
 224         if (IS_ERR(ocotp_dev->base))
 225                 return PTR_ERR(ocotp_dev->base);
 226
 227         ocotp_dev->clk = devm_clk_get(dev, NULL);
 228         if (IS_ERR(ocotp_dev->clk)) {
 229                 dev_err(dev, "failed getting clock, err = %ld\n",
 230                         PTR_ERR(ocotp_dev->clk));
 231                 return PTR_ERR(ocotp_dev->clk);
 232         }
 233         ocotp_dev->dev = dev;
 234         ocotp_dev->timing = vf610_ocotp_calculate_timing(ocotp_dev);
 235
 236         ocotp_config.size = resource_size(res);
 237         ocotp_config.priv = ocotp_dev;
 238         ocotp_config.dev = dev;
 239
 240         ocotp_dev->nvmem = devm_nvmem_register(dev, &ocotp_config);
 241
 242         return PTR_ERR_OR_ZERO(ocotp_dev->nvmem);
 243 }
 244
 245 static struct platform_driver vf610_ocotp_driver = {
 246         .probe = vf610_ocotp_probe,
 247         .driver = {
 248                 .name = "vf610-ocotp",
 249                 .of_match_table = ocotp_of_match,
 250         },
 251 };
 252 module_platform_driver(vf610_ocotp_driver);
 253 MODULE_AUTHOR("Sanchayan Maity <sanchayan.maity@toradex.com>");
 254 MODULE_DESCRIPTION("Vybrid OCOTP driver");
 255 MODULE_LICENSE("GPL v2");