drivers/nvmem/sprd-efuse.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2019 Spreadtrum Communications Inc.
   3
   4 #include <linux/clk.h>
   5 #include <linux/delay.h>
   6 #include <linux/hwspinlock.h>
   7 #include <linux/io.h>
   8 #include <linux/module.h>
   9 #include <linux/nvmem-provider.h>
  10 #include <linux/of_device.h>
  11 #include <linux/platform_device.h>
  12
  13 #define SPRD_EFUSE_ENABLE               0x20
  14 #define SPRD_EFUSE_ERR_FLAG             0x24
  15 #define SPRD_EFUSE_ERR_CLR              0x28
  16 #define SPRD_EFUSE_MAGIC_NUM            0x2c
  17 #define SPRD_EFUSE_FW_CFG               0x50
  18 #define SPRD_EFUSE_PW_SWT               0x54
  19 #define SPRD_EFUSE_MEM(val)             (0x1000 + ((val) << 2))
  20
  21 #define SPRD_EFUSE_VDD_EN               BIT(0)
  22 #define SPRD_EFUSE_AUTO_CHECK_EN        BIT(1)
  23 #define SPRD_EFUSE_DOUBLE_EN            BIT(2)
  24 #define SPRD_EFUSE_MARGIN_RD_EN         BIT(3)
  25 #define SPRD_EFUSE_LOCK_WR_EN           BIT(4)
  26
  27 #define SPRD_EFUSE_ERR_CLR_MASK         GENMASK(13, 0)
  28
  29 #define SPRD_EFUSE_ENK1_ON              BIT(0)
  30 #define SPRD_EFUSE_ENK2_ON              BIT(1)
  31 #define SPRD_EFUSE_PROG_EN              BIT(2)
  32
  33 #define SPRD_EFUSE_MAGIC_NUMBER         0x8810
  34
  35 /* Block width (bytes) definitions */
  36 #define SPRD_EFUSE_BLOCK_WIDTH          4
  37
  38 /*
  39  * The Spreadtrum AP efuse contains 2 parts: normal efuse and secure efuse,
  40  * and we can only access the normal efuse in kernel. So define the normal
  41  * block offset index and normal block numbers.
  42  */
  43 #define SPRD_EFUSE_NORMAL_BLOCK_NUMS    24
  44 #define SPRD_EFUSE_NORMAL_BLOCK_OFFSET  72
  45
  46 /* Timeout (ms) for the trylock of hardware spinlocks */
  47 #define SPRD_EFUSE_HWLOCK_TIMEOUT       5000
  48
  49 /*
  50  * Since different Spreadtrum SoC chip can have different normal block numbers
  51  * and offset. And some SoC can support block double feature, which means
  52  * when reading or writing data to efuse memory, the controller can save double
  53  * data in case one data become incorrect after a long period.
  54  *
  55  * Thus we should save them in the device data structure.
  56  */
  57 struct sprd_efuse_variant_data {
  58         u32 blk_nums;
  59         u32 blk_offset;
  60         bool blk_double;
  61 };
  62
  63 struct sprd_efuse {
  64         struct device *dev;
  65         struct clk *clk;
  66         struct hwspinlock *hwlock;
  67         struct mutex mutex;
  68         void __iomem *base;
  69         const struct sprd_efuse_variant_data *data;
  70 };
  71
  72 static const struct sprd_efuse_variant_data ums312_data = {
  73         .blk_nums = SPRD_EFUSE_NORMAL_BLOCK_NUMS,
  74         .blk_offset = SPRD_EFUSE_NORMAL_BLOCK_OFFSET,
  75         .blk_double = false,
  76 };
  77
  78 /*
  79  * On Spreadtrum platform, we have multi-subsystems will access the unique
  80  * efuse controller, so we need one hardware spinlock to synchronize between
  81  * the multiple subsystems.
  82  */
  83 static int sprd_efuse_lock(struct sprd_efuse *efuse)
  84 {
  85         int ret;
  86
  87         mutex_lock(&efuse->mutex);
  88
  89         ret = hwspin_lock_timeout_raw(efuse->hwlock,
  90                                       SPRD_EFUSE_HWLOCK_TIMEOUT);
  91         if (ret) {
  92                 dev_err(efuse->dev, "timeout get the hwspinlock\n");
  93                 mutex_unlock(&efuse->mutex);
  94                 return ret;
  95         }
  96
  97         return 0;
  98 }
  99
 100 static void sprd_efuse_unlock(struct sprd_efuse *efuse)
 101 {
 102         hwspin_unlock_raw(efuse->hwlock);
 103         mutex_unlock(&efuse->mutex);
 104 }
 105
 106 static void sprd_efuse_set_prog_power(struct sprd_efuse *efuse, bool en)
 107 {
 108         u32 val = readl(efuse->base + SPRD_EFUSE_PW_SWT);
 109
 110         if (en)
 111                 val &= ~SPRD_EFUSE_ENK2_ON;
 112         else
 113                 val &= ~SPRD_EFUSE_ENK1_ON;
 114
 115         writel(val, efuse->base + SPRD_EFUSE_PW_SWT);
 116
 117         /* Open or close efuse power need wait 1000us to make power stable. */
 118         usleep_range(1000, 1200);
 119
 120         if (en)
 121                 val |= SPRD_EFUSE_ENK1_ON;
 122         else
 123                 val |= SPRD_EFUSE_ENK2_ON;
 124
 125         writel(val, efuse->base + SPRD_EFUSE_PW_SWT);
 126
 127         /* Open or close efuse power need wait 1000us to make power stable. */
 128         usleep_range(1000, 1200);
 129 }
 130
 131 static void sprd_efuse_set_read_power(struct sprd_efuse *efuse, bool en)
 132 {
 133         u32 val = readl(efuse->base + SPRD_EFUSE_ENABLE);
 134
 135         if (en)
 136                 val |= SPRD_EFUSE_VDD_EN;
 137         else
 138                 val &= ~SPRD_EFUSE_VDD_EN;
 139
 140         writel(val, efuse->base + SPRD_EFUSE_ENABLE);
 141
 142         /* Open or close efuse power need wait 1000us to make power stable. */
 143         usleep_range(1000, 1200);
 144 }
 145
 146 static void sprd_efuse_set_prog_lock(struct sprd_efuse *efuse, bool en)
 147 {
 148         u32 val = readl(efuse->base + SPRD_EFUSE_ENABLE);
 149
 150         if (en)
 151                 val |= SPRD_EFUSE_LOCK_WR_EN;
 152         else
 153                 val &= ~SPRD_EFUSE_LOCK_WR_EN;
 154
 155         writel(val, efuse->base + SPRD_EFUSE_ENABLE);
 156 }
 157
 158 static void sprd_efuse_set_auto_check(struct sprd_efuse *efuse, bool en)
 159 {
 160         u32 val = readl(efuse->base + SPRD_EFUSE_ENABLE);
 161
 162         if (en)
 163                 val |= SPRD_EFUSE_AUTO_CHECK_EN;
 164         else
 165                 val &= ~SPRD_EFUSE_AUTO_CHECK_EN;
 166
 167         writel(val, efuse->base + SPRD_EFUSE_ENABLE);
 168 }
 169
 170 static void sprd_efuse_set_data_double(struct sprd_efuse *efuse, bool en)
 171 {
 172         u32 val = readl(efuse->base + SPRD_EFUSE_ENABLE);
 173
 174         if (en)
 175                 val |= SPRD_EFUSE_DOUBLE_EN;
 176         else
 177                 val &= ~SPRD_EFUSE_DOUBLE_EN;
 178
 179         writel(val, efuse->base + SPRD_EFUSE_ENABLE);
 180 }
 181
 182 static void sprd_efuse_set_prog_en(struct sprd_efuse *efuse, bool en)
 183 {
 184         u32 val = readl(efuse->base + SPRD_EFUSE_PW_SWT);
 185
 186         if (en)
 187                 val |= SPRD_EFUSE_PROG_EN;
 188         else
 189                 val &= ~SPRD_EFUSE_PROG_EN;
 190
 191         writel(val, efuse->base + SPRD_EFUSE_PW_SWT);
 192 }
 193
 194 static int sprd_efuse_raw_prog(struct sprd_efuse *efuse, u32 blk, bool doub,
 195                                bool lock, u32 *data)
 196 {
 197         u32 status;
 198         int ret = 0;
 199
 200         /*
 201          * We need set the correct magic number before writing the efuse to
 202          * allow programming, and block other programming until we clear the
 203          * magic number.
 204          */
 205         writel(SPRD_EFUSE_MAGIC_NUMBER,
 206                efuse->base + SPRD_EFUSE_MAGIC_NUM);
 207
 208         /*
 209          * Power on the efuse, enable programme and enable double data
 210          * if asked.
 211          */
 212         sprd_efuse_set_prog_power(efuse, true);
 213         sprd_efuse_set_prog_en(efuse, true);
 214         sprd_efuse_set_data_double(efuse, doub);
 215
 216         /*
 217          * Enable the auto-check function to validate if the programming is
 218          * successful.
 219          */
 220         sprd_efuse_set_auto_check(efuse, true);
 221
 222         writel(*data, efuse->base + SPRD_EFUSE_MEM(blk));
 223
 224         /* Disable auto-check and data double after programming */
 225         sprd_efuse_set_auto_check(efuse, false);
 226         sprd_efuse_set_data_double(efuse, false);
 227
 228         /*
 229          * Check the efuse error status, if the programming is successful,
 230          * we should lock this efuse block to avoid programming again.
 231          */
 232         status = readl(efuse->base + SPRD_EFUSE_ERR_FLAG);
 233         if (status) {
 234                 dev_err(efuse->dev,
 235                         "write error status %d of block %d\n", ret, blk);
 236
 237                 writel(SPRD_EFUSE_ERR_CLR_MASK,
 238                        efuse->base + SPRD_EFUSE_ERR_CLR);
 239                 ret = -EBUSY;
 240         } else {
 241                 sprd_efuse_set_prog_lock(efuse, lock);
 242                 writel(*data, efuse->base + SPRD_EFUSE_MEM(blk));
 243                 sprd_efuse_set_prog_lock(efuse, false);
 244         }
 245
 246         sprd_efuse_set_prog_power(efuse, false);
 247         writel(0, efuse->base + SPRD_EFUSE_MAGIC_NUM);
 248
 249         return ret;
 250 }
 251
 252 static int sprd_efuse_raw_read(struct sprd_efuse *efuse, int blk, u32 *val,
 253                                bool doub)
 254 {
 255         u32 status;
 256
 257         /*
 258          * Need power on the efuse before reading data from efuse, and will
 259          * power off the efuse after reading process.
 260          */
 261         sprd_efuse_set_read_power(efuse, true);
 262
 263         /* Enable double data if asked */
 264         sprd_efuse_set_data_double(efuse, doub);
 265
 266         /* Start to read data from efuse block */
 267         *val = readl(efuse->base + SPRD_EFUSE_MEM(blk));
 268
 269         /* Disable double data */
 270         sprd_efuse_set_data_double(efuse, false);
 271
 272         /* Power off the efuse */
 273         sprd_efuse_set_read_power(efuse, false);
 274
 275         /*
 276          * Check the efuse error status and clear them if there are some
 277          * errors occurred.
 278          */
 279         status = readl(efuse->base + SPRD_EFUSE_ERR_FLAG);
 280         if (status) {
 281                 dev_err(efuse->dev,
 282                         "read error status %d of block %d\n", status, blk);
 283
 284                 writel(SPRD_EFUSE_ERR_CLR_MASK,
 285                        efuse->base + SPRD_EFUSE_ERR_CLR);
 286                 return -EBUSY;
 287         }
 288
 289         return 0;
 290 }
 291
 292 static int sprd_efuse_read(void *context, u32 offset, void *val, size_t bytes)
 293 {
 294         struct sprd_efuse *efuse = context;
 295         bool blk_double = efuse->data->blk_double;
 296         u32 index = offset / SPRD_EFUSE_BLOCK_WIDTH + efuse->data->blk_offset;
 297         u32 blk_offset = (offset % SPRD_EFUSE_BLOCK_WIDTH) * BITS_PER_BYTE;
 298         u32 data;
 299         int ret;
 300
 301         ret = sprd_efuse_lock(efuse);
 302         if (ret)
 303                 return ret;
 304
 305         ret = clk_prepare_enable(efuse->clk);
 306         if (ret)
 307                 goto unlock;
 308
 309         ret = sprd_efuse_raw_read(efuse, index, &data, blk_double);
 310         if (!ret) {
 311                 data >>= blk_offset;
 312                 memcpy(val, &data, bytes);
 313         }
 314
 315         clk_disable_unprepare(efuse->clk);
 316
 317 unlock:
 318         sprd_efuse_unlock(efuse);
 319         return ret;
 320 }
 321
 322 static int sprd_efuse_write(void *context, u32 offset, void *val, size_t bytes)
 323 {
 324         struct sprd_efuse *efuse = context;
 325         int ret;
 326
 327         ret = sprd_efuse_lock(efuse);
 328         if (ret)
 329                 return ret;
 330
 331         ret = clk_prepare_enable(efuse->clk);
 332         if (ret)
 333                 goto unlock;
 334
 335         ret = sprd_efuse_raw_prog(efuse, offset, false, false, val);
 336
 337         clk_disable_unprepare(efuse->clk);
 338
 339 unlock:
 340         sprd_efuse_unlock(efuse);
 341         return ret;
 342 }
 343
 344 static int sprd_efuse_probe(struct platform_device *pdev)
 345 {
 346         struct device_node *np = pdev->dev.of_node;
 347         struct nvmem_device *nvmem;
 348         struct nvmem_config econfig = { };
 349         struct sprd_efuse *efuse;
 350         const struct sprd_efuse_variant_data *pdata;
 351         int ret;
 352
 353         pdata = of_device_get_match_data(&pdev->dev);
 354         if (!pdata) {
 355                 dev_err(&pdev->dev, "No matching driver data found\n");
 356                 return -EINVAL;
 357         }
 358
 359         efuse = devm_kzalloc(&pdev->dev, sizeof(*efuse), GFP_KERNEL);
 360         if (!efuse)
 361                 return -ENOMEM;
 362
 363         efuse->base = devm_platform_ioremap_resource(pdev, 0);
 364         if (!efuse->base)
 365                 return -ENOMEM;
 366
 367         ret = of_hwspin_lock_get_id(np, 0);
 368         if (ret < 0) {
 369                 dev_err(&pdev->dev, "failed to get hwlock id\n");
 370                 return ret;
 371         }
 372
 373         efuse->hwlock = devm_hwspin_lock_request_specific(&pdev->dev, ret);
 374         if (!efuse->hwlock) {
 375                 dev_err(&pdev->dev, "failed to request hwlock\n");
 376                 return -ENXIO;
 377         }
 378
 379         efuse->clk = devm_clk_get(&pdev->dev, "enable");
 380         if (IS_ERR(efuse->clk)) {
 381                 dev_err(&pdev->dev, "failed to get enable clock\n");
 382                 return PTR_ERR(efuse->clk);
 383         }
 384
 385         mutex_init(&efuse->mutex);
 386         efuse->dev = &pdev->dev;
 387         efuse->data = pdata;
 388
 389         econfig.stride = 1;
 390         econfig.word_size = 1;
 391         econfig.read_only = false;
 392         econfig.name = "sprd-efuse";
 393         econfig.size = efuse->data->blk_nums * SPRD_EFUSE_BLOCK_WIDTH;
 394         econfig.reg_read = sprd_efuse_read;
 395         econfig.reg_write = sprd_efuse_write;
 396         econfig.priv = efuse;
 397         econfig.dev = &pdev->dev;
 398         nvmem = devm_nvmem_register(&pdev->dev, &econfig);
 399         if (IS_ERR(nvmem)) {
 400                 dev_err(&pdev->dev, "failed to register nvmem\n");
 401                 return PTR_ERR(nvmem);
 402         }
 403
 404         return 0;
 405 }
 406
 407 static const struct of_device_id sprd_efuse_of_match[] = {
 408         { .compatible = "sprd,ums312-efuse", .data = &ums312_data },
 409         { }
 410 };
 411
 412 static struct platform_driver sprd_efuse_driver = {
 413         .probe = sprd_efuse_probe,
 414         .driver = {
 415                 .name = "sprd-efuse",
 416                 .of_match_table = sprd_efuse_of_match,
 417         },
 418 };
 419
 420 module_platform_driver(sprd_efuse_driver);
 421
 422 MODULE_AUTHOR("Freeman Liu <freeman.liu@spreadtrum.com>");
 423 MODULE_DESCRIPTION("Spreadtrum AP efuse driver");
 424 MODULE_LICENSE("GPL v2");