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         if (lock)
 221                 sprd_efuse_set_auto_check(efuse, true);
 222
 223         writel(*data, efuse->base + SPRD_EFUSE_MEM(blk));
 224
 225         /* Disable auto-check and data double after programming */
 226         if (lock)
 227                 sprd_efuse_set_auto_check(efuse, false);
 228         sprd_efuse_set_data_double(efuse, false);
 229
 230         /*
 231          * Check the efuse error status, if the programming is successful,
 232          * we should lock this efuse block to avoid programming again.
 233          */
 234         status = readl(efuse->base + SPRD_EFUSE_ERR_FLAG);
 235         if (status) {
 236                 dev_err(efuse->dev,
 237                         "write error status %d of block %d\n", ret, blk);
 238
 239                 writel(SPRD_EFUSE_ERR_CLR_MASK,
 240                        efuse->base + SPRD_EFUSE_ERR_CLR);
 241                 ret = -EBUSY;
 242         } else if (lock) {
 243                 sprd_efuse_set_prog_lock(efuse, lock);
 244                 writel(0, efuse->base + SPRD_EFUSE_MEM(blk));
 245                 sprd_efuse_set_prog_lock(efuse, false);
 246         }
 247
 248         sprd_efuse_set_prog_power(efuse, false);
 249         writel(0, efuse->base + SPRD_EFUSE_MAGIC_NUM);
 250
 251         return ret;
 252 }
 253
 254 static int sprd_efuse_raw_read(struct sprd_efuse *efuse, int blk, u32 *val,
 255                                bool doub)
 256 {
 257         u32 status;
 258
 259         /*
 260          * Need power on the efuse before reading data from efuse, and will
 261          * power off the efuse after reading process.
 262          */
 263         sprd_efuse_set_read_power(efuse, true);
 264
 265         /* Enable double data if asked */
 266         sprd_efuse_set_data_double(efuse, doub);
 267
 268         /* Start to read data from efuse block */
 269         *val = readl(efuse->base + SPRD_EFUSE_MEM(blk));
 270
 271         /* Disable double data */
 272         sprd_efuse_set_data_double(efuse, false);
 273
 274         /* Power off the efuse */
 275         sprd_efuse_set_read_power(efuse, false);
 276
 277         /*
 278          * Check the efuse error status and clear them if there are some
 279          * errors occurred.
 280          */
 281         status = readl(efuse->base + SPRD_EFUSE_ERR_FLAG);
 282         if (status) {
 283                 dev_err(efuse->dev,
 284                         "read error status %d of block %d\n", status, blk);
 285
 286                 writel(SPRD_EFUSE_ERR_CLR_MASK,
 287                        efuse->base + SPRD_EFUSE_ERR_CLR);
 288                 return -EBUSY;
 289         }
 290
 291         return 0;
 292 }
 293
 294 static int sprd_efuse_read(void *context, u32 offset, void *val, size_t bytes)
 295 {
 296         struct sprd_efuse *efuse = context;
 297         bool blk_double = efuse->data->blk_double;
 298         u32 index = offset / SPRD_EFUSE_BLOCK_WIDTH + efuse->data->blk_offset;
 299         u32 blk_offset = (offset % SPRD_EFUSE_BLOCK_WIDTH) * BITS_PER_BYTE;
 300         u32 data;
 301         int ret;
 302
 303         ret = sprd_efuse_lock(efuse);
 304         if (ret)
 305                 return ret;
 306
 307         ret = clk_prepare_enable(efuse->clk);
 308         if (ret)
 309                 goto unlock;
 310
 311         ret = sprd_efuse_raw_read(efuse, index, &data, blk_double);
 312         if (!ret) {
 313                 data >>= blk_offset;
 314                 memcpy(val, &data, bytes);
 315         }
 316
 317         clk_disable_unprepare(efuse->clk);
 318
 319 unlock:
 320         sprd_efuse_unlock(efuse);
 321         return ret;
 322 }
 323
 324 static int sprd_efuse_write(void *context, u32 offset, void *val, size_t bytes)
 325 {
 326         struct sprd_efuse *efuse = context;
 327         bool blk_double = efuse->data->blk_double;
 328         bool lock;
 329         int ret;
 330
 331         ret = sprd_efuse_lock(efuse);
 332         if (ret)
 333                 return ret;
 334
 335         ret = clk_prepare_enable(efuse->clk);
 336         if (ret)
 337                 goto unlock;
 338
 339         /*
 340          * If the writing bytes are equal with the block width, which means the
 341          * whole block will be programmed. For this case, we should not allow
 342          * this block to be programmed again by locking this block.
 343          *
 344          * If the block was programmed partially, we should allow this block to
 345          * be programmed again.
 346          */
 347         if (bytes < SPRD_EFUSE_BLOCK_WIDTH)
 348                 lock = false;
 349         else
 350                 lock = true;
 351
 352         ret = sprd_efuse_raw_prog(efuse, offset, blk_double, lock, val);
 353
 354         clk_disable_unprepare(efuse->clk);
 355
 356 unlock:
 357         sprd_efuse_unlock(efuse);
 358         return ret;
 359 }
 360
 361 static int sprd_efuse_probe(struct platform_device *pdev)
 362 {
 363         struct device_node *np = pdev->dev.of_node;
 364         struct nvmem_device *nvmem;
 365         struct nvmem_config econfig = { };
 366         struct sprd_efuse *efuse;
 367         const struct sprd_efuse_variant_data *pdata;
 368         int ret;
 369
 370         pdata = of_device_get_match_data(&pdev->dev);
 371         if (!pdata) {
 372                 dev_err(&pdev->dev, "No matching driver data found\n");
 373                 return -EINVAL;
 374         }
 375
 376         efuse = devm_kzalloc(&pdev->dev, sizeof(*efuse), GFP_KERNEL);
 377         if (!efuse)
 378                 return -ENOMEM;
 379
 380         efuse->base = devm_platform_ioremap_resource(pdev, 0);
 381         if (IS_ERR(efuse->base))
 382                 return PTR_ERR(efuse->base);
 383
 384         ret = of_hwspin_lock_get_id(np, 0);
 385         if (ret < 0) {
 386                 dev_err(&pdev->dev, "failed to get hwlock id\n");
 387                 return ret;
 388         }
 389
 390         efuse->hwlock = devm_hwspin_lock_request_specific(&pdev->dev, ret);
 391         if (!efuse->hwlock) {
 392                 dev_err(&pdev->dev, "failed to request hwlock\n");
 393                 return -ENXIO;
 394         }
 395
 396         efuse->clk = devm_clk_get(&pdev->dev, "enable");
 397         if (IS_ERR(efuse->clk)) {
 398                 dev_err(&pdev->dev, "failed to get enable clock\n");
 399                 return PTR_ERR(efuse->clk);
 400         }
 401
 402         mutex_init(&efuse->mutex);
 403         efuse->dev = &pdev->dev;
 404         efuse->data = pdata;
 405
 406         econfig.stride = 1;
 407         econfig.word_size = 1;
 408         econfig.read_only = false;
 409         econfig.name = "sprd-efuse";
 410         econfig.size = efuse->data->blk_nums * SPRD_EFUSE_BLOCK_WIDTH;
 411         econfig.reg_read = sprd_efuse_read;
 412         econfig.reg_write = sprd_efuse_write;
 413         econfig.priv = efuse;
 414         econfig.dev = &pdev->dev;
 415         nvmem = devm_nvmem_register(&pdev->dev, &econfig);
 416         if (IS_ERR(nvmem)) {
 417                 dev_err(&pdev->dev, "failed to register nvmem\n");
 418                 return PTR_ERR(nvmem);
 419         }
 420
 421         return 0;
 422 }
 423
 424 static const struct of_device_id sprd_efuse_of_match[] = {
 425         { .compatible = "sprd,ums312-efuse", .data = &ums312_data },
 426         { }
 427 };
 428
 429 static struct platform_driver sprd_efuse_driver = {
 430         .probe = sprd_efuse_probe,
 431         .driver = {
 432                 .name = "sprd-efuse",
 433                 .of_match_table = sprd_efuse_of_match,
 434         },
 435 };
 436
 437 module_platform_driver(sprd_efuse_driver);
 438
 439 MODULE_AUTHOR("Freeman Liu <freeman.liu@spreadtrum.com>");
 440 MODULE_DESCRIPTION("Spreadtrum AP efuse driver");
 441 MODULE_LICENSE("GPL v2");