drivers/mtd/spi-nor/intel-spi.c

   1 /*
   2  * Intel PCH/PCU SPI flash driver.
   3  *
   4  * Copyright (C) 2016, Intel Corporation
   5  * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/err.h>
  13 #include <linux/io.h>
  14 #include <linux/iopoll.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/sizes.h>
  18 #include <linux/mtd/mtd.h>
  19 #include <linux/mtd/partitions.h>
  20 #include <linux/mtd/spi-nor.h>
  21 #include <linux/platform_data/intel-spi.h>
  22
  23 #include "intel-spi.h"
  24
  25 /* Offsets are from @ispi->base */
  26 #define BFPREG                          0x00
  27
  28 #define HSFSTS_CTL                      0x04
  29 #define HSFSTS_CTL_FSMIE                BIT(31)
  30 #define HSFSTS_CTL_FDBC_SHIFT           24
  31 #define HSFSTS_CTL_FDBC_MASK            (0x3f << HSFSTS_CTL_FDBC_SHIFT)
  32
  33 #define HSFSTS_CTL_FCYCLE_SHIFT         17
  34 #define HSFSTS_CTL_FCYCLE_MASK          (0x0f << HSFSTS_CTL_FCYCLE_SHIFT)
  35 /* HW sequencer opcodes */
  36 #define HSFSTS_CTL_FCYCLE_READ          (0x00 << HSFSTS_CTL_FCYCLE_SHIFT)
  37 #define HSFSTS_CTL_FCYCLE_WRITE         (0x02 << HSFSTS_CTL_FCYCLE_SHIFT)
  38 #define HSFSTS_CTL_FCYCLE_ERASE         (0x03 << HSFSTS_CTL_FCYCLE_SHIFT)
  39 #define HSFSTS_CTL_FCYCLE_ERASE_64K     (0x04 << HSFSTS_CTL_FCYCLE_SHIFT)
  40 #define HSFSTS_CTL_FCYCLE_RDID          (0x06 << HSFSTS_CTL_FCYCLE_SHIFT)
  41 #define HSFSTS_CTL_FCYCLE_WRSR          (0x07 << HSFSTS_CTL_FCYCLE_SHIFT)
  42 #define HSFSTS_CTL_FCYCLE_RDSR          (0x08 << HSFSTS_CTL_FCYCLE_SHIFT)
  43
  44 #define HSFSTS_CTL_FGO                  BIT(16)
  45 #define HSFSTS_CTL_FLOCKDN              BIT(15)
  46 #define HSFSTS_CTL_FDV                  BIT(14)
  47 #define HSFSTS_CTL_SCIP                 BIT(5)
  48 #define HSFSTS_CTL_AEL                  BIT(2)
  49 #define HSFSTS_CTL_FCERR                BIT(1)
  50 #define HSFSTS_CTL_FDONE                BIT(0)
  51
  52 #define FADDR                           0x08
  53 #define DLOCK                           0x0c
  54 #define FDATA(n)                        (0x10 + ((n) * 4))
  55
  56 #define FRACC                           0x50
  57
  58 #define FREG(n)                         (0x54 + ((n) * 4))
  59 #define FREG_BASE_MASK                  0x3fff
  60 #define FREG_LIMIT_SHIFT                16
  61 #define FREG_LIMIT_MASK                 (0x03fff << FREG_LIMIT_SHIFT)
  62
  63 /* Offset is from @ispi->pregs */
  64 #define PR(n)                           ((n) * 4)
  65 #define PR_WPE                          BIT(31)
  66 #define PR_LIMIT_SHIFT                  16
  67 #define PR_LIMIT_MASK                   (0x3fff << PR_LIMIT_SHIFT)
  68 #define PR_RPE                          BIT(15)
  69 #define PR_BASE_MASK                    0x3fff
  70 /* Last PR is GPR0 */
  71 #define PR_NUM                          (5 + 1)
  72
  73 /* Offsets are from @ispi->sregs */
  74 #define SSFSTS_CTL                      0x00
  75 #define SSFSTS_CTL_FSMIE                BIT(23)
  76 #define SSFSTS_CTL_DS                   BIT(22)
  77 #define SSFSTS_CTL_DBC_SHIFT            16
  78 #define SSFSTS_CTL_SPOP                 BIT(11)
  79 #define SSFSTS_CTL_ACS                  BIT(10)
  80 #define SSFSTS_CTL_SCGO                 BIT(9)
  81 #define SSFSTS_CTL_COP_SHIFT            12
  82 #define SSFSTS_CTL_FRS                  BIT(7)
  83 #define SSFSTS_CTL_DOFRS                BIT(6)
  84 #define SSFSTS_CTL_AEL                  BIT(4)
  85 #define SSFSTS_CTL_FCERR                BIT(3)
  86 #define SSFSTS_CTL_FDONE                BIT(2)
  87 #define SSFSTS_CTL_SCIP                 BIT(0)
  88
  89 #define PREOP_OPTYPE                    0x04
  90 #define OPMENU0                         0x08
  91 #define OPMENU1                         0x0c
  92
  93 /* CPU specifics */
  94 #define BYT_PR                          0x74
  95 #define BYT_SSFSTS_CTL                  0x90
  96 #define BYT_BCR                         0xfc
  97 #define BYT_BCR_WPD                     BIT(0)
  98 #define BYT_FREG_NUM                    5
  99
 100 #define LPT_PR                          0x74
 101 #define LPT_SSFSTS_CTL                  0x90
 102 #define LPT_FREG_NUM                    5
 103
 104 #define BXT_PR                          0x84
 105 #define BXT_SSFSTS_CTL                  0xa0
 106 #define BXT_FREG_NUM                    12
 107
 108 #define INTEL_SPI_TIMEOUT               5000 /* ms */
 109 #define INTEL_SPI_FIFO_SZ               64
 110
 111 /**
 112  * struct intel_spi - Driver private data
 113  * @dev: Device pointer
 114  * @info: Pointer to board specific info
 115  * @nor: SPI NOR layer structure
 116  * @base: Beginning of MMIO space
 117  * @pregs: Start of protection registers
 118  * @sregs: Start of software sequencer registers
 119  * @nregions: Maximum number of regions
 120  * @writeable: Is the chip writeable
 121  * @swseq: Use SW sequencer in register reads/writes
 122  * @erase_64k: 64k erase supported
 123  * @opcodes: Opcodes which are supported. This are programmed by BIOS
 124  *           before it locks down the controller.
 125  * @preopcodes: Preopcodes which are supported.
 126  */
 127 struct intel_spi {
 128         struct device *dev;
 129         const struct intel_spi_boardinfo *info;
 130         struct spi_nor nor;
 131         void __iomem *base;
 132         void __iomem *pregs;
 133         void __iomem *sregs;
 134         size_t nregions;
 135         bool writeable;
 136         bool swseq;
 137         bool erase_64k;
 138         u8 opcodes[8];
 139         u8 preopcodes[2];
 140 };
 141
 142 static bool writeable;
 143 module_param(writeable, bool, 0);
 144 MODULE_PARM_DESC(writeable, "Enable write access to SPI flash chip (default=0)");
 145
 146 static void intel_spi_dump_regs(struct intel_spi *ispi)
 147 {
 148         u32 value;
 149         int i;
 150
 151         dev_dbg(ispi->dev, "BFPREG=0x%08x\n", readl(ispi->base + BFPREG));
 152
 153         value = readl(ispi->base + HSFSTS_CTL);
 154         dev_dbg(ispi->dev, "HSFSTS_CTL=0x%08x\n", value);
 155         if (value & HSFSTS_CTL_FLOCKDN)
 156                 dev_dbg(ispi->dev, "-> Locked\n");
 157
 158         dev_dbg(ispi->dev, "FADDR=0x%08x\n", readl(ispi->base + FADDR));
 159         dev_dbg(ispi->dev, "DLOCK=0x%08x\n", readl(ispi->base + DLOCK));
 160
 161         for (i = 0; i < 16; i++)
 162                 dev_dbg(ispi->dev, "FDATA(%d)=0x%08x\n",
 163                         i, readl(ispi->base + FDATA(i)));
 164
 165         dev_dbg(ispi->dev, "FRACC=0x%08x\n", readl(ispi->base + FRACC));
 166
 167         for (i = 0; i < ispi->nregions; i++)
 168                 dev_dbg(ispi->dev, "FREG(%d)=0x%08x\n", i,
 169                         readl(ispi->base + FREG(i)));
 170         for (i = 0; i < PR_NUM; i++)
 171                 dev_dbg(ispi->dev, "PR(%d)=0x%08x\n", i,
 172                         readl(ispi->pregs + PR(i)));
 173
 174         value = readl(ispi->sregs + SSFSTS_CTL);
 175         dev_dbg(ispi->dev, "SSFSTS_CTL=0x%08x\n", value);
 176         dev_dbg(ispi->dev, "PREOP_OPTYPE=0x%08x\n",
 177                 readl(ispi->sregs + PREOP_OPTYPE));
 178         dev_dbg(ispi->dev, "OPMENU0=0x%08x\n", readl(ispi->sregs + OPMENU0));
 179         dev_dbg(ispi->dev, "OPMENU1=0x%08x\n", readl(ispi->sregs + OPMENU1));
 180
 181         if (ispi->info->type == INTEL_SPI_BYT)
 182                 dev_dbg(ispi->dev, "BCR=0x%08x\n", readl(ispi->base + BYT_BCR));
 183
 184         dev_dbg(ispi->dev, "Protected regions:\n");
 185         for (i = 0; i < PR_NUM; i++) {
 186                 u32 base, limit;
 187
 188                 value = readl(ispi->pregs + PR(i));
 189                 if (!(value & (PR_WPE | PR_RPE)))
 190                         continue;
 191
 192                 limit = (value & PR_LIMIT_MASK) >> PR_LIMIT_SHIFT;
 193                 base = value & PR_BASE_MASK;
 194
 195                 dev_dbg(ispi->dev, " %02d base: 0x%08x limit: 0x%08x [%c%c]\n",
 196                          i, base << 12, (limit << 12) | 0xfff,
 197                          value & PR_WPE ? 'W' : '.',
 198                          value & PR_RPE ? 'R' : '.');
 199         }
 200
 201         dev_dbg(ispi->dev, "Flash regions:\n");
 202         for (i = 0; i < ispi->nregions; i++) {
 203                 u32 region, base, limit;
 204
 205                 region = readl(ispi->base + FREG(i));
 206                 base = region & FREG_BASE_MASK;
 207                 limit = (region & FREG_LIMIT_MASK) >> FREG_LIMIT_SHIFT;
 208
 209                 if (base >= limit || (i > 0 && limit == 0))
 210                         dev_dbg(ispi->dev, " %02d disabled\n", i);
 211                 else
 212                         dev_dbg(ispi->dev, " %02d base: 0x%08x limit: 0x%08x\n",
 213                                  i, base << 12, (limit << 12) | 0xfff);
 214         }
 215
 216         dev_dbg(ispi->dev, "Using %cW sequencer for register access\n",
 217                 ispi->swseq ? 'S' : 'H');
 218 }
 219
 220 /* Reads max INTEL_SPI_FIFO_SZ bytes from the device fifo */
 221 static int intel_spi_read_block(struct intel_spi *ispi, void *buf, size_t size)
 222 {
 223         size_t bytes;
 224         int i = 0;
 225
 226         if (size > INTEL_SPI_FIFO_SZ)
 227                 return -EINVAL;
 228
 229         while (size > 0) {
 230                 bytes = min_t(size_t, size, 4);
 231                 memcpy_fromio(buf, ispi->base + FDATA(i), bytes);
 232                 size -= bytes;
 233                 buf += bytes;
 234                 i++;
 235         }
 236
 237         return 0;
 238 }
 239
 240 /* Writes max INTEL_SPI_FIFO_SZ bytes to the device fifo */
 241 static int intel_spi_write_block(struct intel_spi *ispi, const void *buf,
 242                                  size_t size)
 243 {
 244         size_t bytes;
 245         int i = 0;
 246
 247         if (size > INTEL_SPI_FIFO_SZ)
 248                 return -EINVAL;
 249
 250         while (size > 0) {
 251                 bytes = min_t(size_t, size, 4);
 252                 memcpy_toio(ispi->base + FDATA(i), buf, bytes);
 253                 size -= bytes;
 254                 buf += bytes;
 255                 i++;
 256         }
 257
 258         return 0;
 259 }
 260
 261 static int intel_spi_wait_hw_busy(struct intel_spi *ispi)
 262 {
 263         u32 val;
 264
 265         return readl_poll_timeout(ispi->base + HSFSTS_CTL, val,
 266                                   !(val & HSFSTS_CTL_SCIP), 0,
 267                                   INTEL_SPI_TIMEOUT * 1000);
 268 }
 269
 270 static int intel_spi_wait_sw_busy(struct intel_spi *ispi)
 271 {
 272         u32 val;
 273
 274         return readl_poll_timeout(ispi->sregs + SSFSTS_CTL, val,
 275                                   !(val & SSFSTS_CTL_SCIP), 0,
 276                                   INTEL_SPI_TIMEOUT * 1000);
 277 }
 278
 279 static int intel_spi_init(struct intel_spi *ispi)
 280 {
 281         u32 opmenu0, opmenu1, val;
 282         int i;
 283
 284         switch (ispi->info->type) {
 285         case INTEL_SPI_BYT:
 286                 ispi->sregs = ispi->base + BYT_SSFSTS_CTL;
 287                 ispi->pregs = ispi->base + BYT_PR;
 288                 ispi->nregions = BYT_FREG_NUM;
 289
 290                 if (writeable) {
 291                         /* Disable write protection */
 292                         val = readl(ispi->base + BYT_BCR);
 293                         if (!(val & BYT_BCR_WPD)) {
 294                                 val |= BYT_BCR_WPD;
 295                                 writel(val, ispi->base + BYT_BCR);
 296                                 val = readl(ispi->base + BYT_BCR);
 297                         }
 298
 299                         ispi->writeable = !!(val & BYT_BCR_WPD);
 300                 }
 301
 302                 break;
 303
 304         case INTEL_SPI_LPT:
 305                 ispi->sregs = ispi->base + LPT_SSFSTS_CTL;
 306                 ispi->pregs = ispi->base + LPT_PR;
 307                 ispi->nregions = LPT_FREG_NUM;
 308                 break;
 309
 310         case INTEL_SPI_BXT:
 311                 ispi->sregs = ispi->base + BXT_SSFSTS_CTL;
 312                 ispi->pregs = ispi->base + BXT_PR;
 313                 ispi->nregions = BXT_FREG_NUM;
 314                 ispi->erase_64k = true;
 315                 break;
 316
 317         default:
 318                 return -EINVAL;
 319         }
 320
 321         /* Disable #SMI generation */
 322         val = readl(ispi->base + HSFSTS_CTL);
 323         val &= ~HSFSTS_CTL_FSMIE;
 324         writel(val, ispi->base + HSFSTS_CTL);
 325
 326         /*
 327          * BIOS programs allowed opcodes and then locks down the register.
 328          * So read back what opcodes it decided to support. That's the set
 329          * we are going to support as well.
 330          */
 331         opmenu0 = readl(ispi->sregs + OPMENU0);
 332         opmenu1 = readl(ispi->sregs + OPMENU1);
 333
 334         /*
 335          * Some controllers can only do basic operations using hardware
 336          * sequencer. All other operations are supposed to be carried out
 337          * using software sequencer. If we find that BIOS has programmed
 338          * opcodes for the software sequencer we use that over the hardware
 339          * sequencer.
 340          */
 341         if (opmenu0 && opmenu1) {
 342                 for (i = 0; i < ARRAY_SIZE(ispi->opcodes) / 2; i++) {
 343                         ispi->opcodes[i] = opmenu0 >> i * 8;
 344                         ispi->opcodes[i + 4] = opmenu1 >> i * 8;
 345                 }
 346
 347                 val = readl(ispi->sregs + PREOP_OPTYPE);
 348                 ispi->preopcodes[0] = val;
 349                 ispi->preopcodes[1] = val >> 8;
 350
 351                 /* Disable #SMI generation from SW sequencer */
 352                 val = readl(ispi->sregs + SSFSTS_CTL);
 353                 val &= ~SSFSTS_CTL_FSMIE;
 354                 writel(val, ispi->sregs + SSFSTS_CTL);
 355
 356                 ispi->swseq = true;
 357         }
 358
 359         intel_spi_dump_regs(ispi);
 360
 361         return 0;
 362 }
 363
 364 static int intel_spi_opcode_index(struct intel_spi *ispi, u8 opcode)
 365 {
 366         int i;
 367
 368         for (i = 0; i < ARRAY_SIZE(ispi->opcodes); i++)
 369                 if (ispi->opcodes[i] == opcode)
 370                         return i;
 371         return -EINVAL;
 372 }
 373
 374 static int intel_spi_hw_cycle(struct intel_spi *ispi, u8 opcode, u8 *buf,
 375                               int len)
 376 {
 377         u32 val, status;
 378         int ret;
 379
 380         val = readl(ispi->base + HSFSTS_CTL);
 381         val &= ~(HSFSTS_CTL_FCYCLE_MASK | HSFSTS_CTL_FDBC_MASK);
 382
 383         switch (opcode) {
 384         case SPINOR_OP_RDID:
 385                 val |= HSFSTS_CTL_FCYCLE_RDID;
 386                 break;
 387         case SPINOR_OP_WRSR:
 388                 val |= HSFSTS_CTL_FCYCLE_WRSR;
 389                 break;
 390         case SPINOR_OP_RDSR:
 391                 val |= HSFSTS_CTL_FCYCLE_RDSR;
 392                 break;
 393         default:
 394                 return -EINVAL;
 395         }
 396
 397         val |= (len - 1) << HSFSTS_CTL_FDBC_SHIFT;
 398         val |= HSFSTS_CTL_FCERR | HSFSTS_CTL_FDONE;
 399         val |= HSFSTS_CTL_FGO;
 400         writel(val, ispi->base + HSFSTS_CTL);
 401
 402         ret = intel_spi_wait_hw_busy(ispi);
 403         if (ret)
 404                 return ret;
 405
 406         status = readl(ispi->base + HSFSTS_CTL);
 407         if (status & HSFSTS_CTL_FCERR)
 408                 return -EIO;
 409         else if (status & HSFSTS_CTL_AEL)
 410                 return -EACCES;
 411
 412         return 0;
 413 }
 414
 415 static int intel_spi_sw_cycle(struct intel_spi *ispi, u8 opcode, u8 *buf,
 416                               int len)
 417 {
 418         u32 val, status;
 419         int ret;
 420
 421         ret = intel_spi_opcode_index(ispi, opcode);
 422         if (ret < 0)
 423                 return ret;
 424
 425         val = (len << SSFSTS_CTL_DBC_SHIFT) | SSFSTS_CTL_DS;
 426         val |= ret << SSFSTS_CTL_COP_SHIFT;
 427         val |= SSFSTS_CTL_FCERR | SSFSTS_CTL_FDONE;
 428         val |= SSFSTS_CTL_SCGO;
 429         writel(val, ispi->sregs + SSFSTS_CTL);
 430
 431         ret = intel_spi_wait_sw_busy(ispi);
 432         if (ret)
 433                 return ret;
 434
 435         status = readl(ispi->base + SSFSTS_CTL);
 436         if (status & SSFSTS_CTL_FCERR)
 437                 return -EIO;
 438         else if (status & SSFSTS_CTL_AEL)
 439                 return -EACCES;
 440
 441         return 0;
 442 }
 443
 444 static int intel_spi_read_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
 445 {
 446         struct intel_spi *ispi = nor->priv;
 447         int ret;
 448
 449         /* Address of the first chip */
 450         writel(0, ispi->base + FADDR);
 451
 452         if (ispi->swseq)
 453                 ret = intel_spi_sw_cycle(ispi, opcode, buf, len);
 454         else
 455                 ret = intel_spi_hw_cycle(ispi, opcode, buf, len);
 456
 457         if (ret)
 458                 return ret;
 459
 460         return intel_spi_read_block(ispi, buf, len);
 461 }
 462
 463 static int intel_spi_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
 464 {
 465         struct intel_spi *ispi = nor->priv;
 466         int ret;
 467
 468         /*
 469          * This is handled with atomic operation and preop code in Intel
 470          * controller so skip it here now.
 471          */
 472         if (opcode == SPINOR_OP_WREN)
 473                 return 0;
 474
 475         writel(0, ispi->base + FADDR);
 476
 477         /* Write the value beforehand */
 478         ret = intel_spi_write_block(ispi, buf, len);
 479         if (ret)
 480                 return ret;
 481
 482         if (ispi->swseq)
 483                 return intel_spi_sw_cycle(ispi, opcode, buf, len);
 484         return intel_spi_hw_cycle(ispi, opcode, buf, len);
 485 }
 486
 487 static ssize_t intel_spi_read(struct spi_nor *nor, loff_t from, size_t len,
 488                               u_char *read_buf)
 489 {
 490         struct intel_spi *ispi = nor->priv;
 491         size_t block_size, retlen = 0;
 492         u32 val, status;
 493         ssize_t ret;
 494
 495         switch (nor->read_opcode) {
 496         case SPINOR_OP_READ:
 497         case SPINOR_OP_READ_FAST:
 498                 break;
 499         default:
 500                 return -EINVAL;
 501         }
 502
 503         while (len > 0) {
 504                 block_size = min_t(size_t, len, INTEL_SPI_FIFO_SZ);
 505
 506                 writel(from, ispi->base + FADDR);
 507
 508                 val = readl(ispi->base + HSFSTS_CTL);
 509                 val &= ~(HSFSTS_CTL_FDBC_MASK | HSFSTS_CTL_FCYCLE_MASK);
 510                 val |= HSFSTS_CTL_AEL | HSFSTS_CTL_FCERR | HSFSTS_CTL_FDONE;
 511                 val |= (block_size - 1) << HSFSTS_CTL_FDBC_SHIFT;
 512                 val |= HSFSTS_CTL_FCYCLE_READ;
 513                 val |= HSFSTS_CTL_FGO;
 514                 writel(val, ispi->base + HSFSTS_CTL);
 515
 516                 ret = intel_spi_wait_hw_busy(ispi);
 517                 if (ret)
 518                         return ret;
 519
 520                 status = readl(ispi->base + HSFSTS_CTL);
 521                 if (status & HSFSTS_CTL_FCERR)
 522                         ret = -EIO;
 523                 else if (status & HSFSTS_CTL_AEL)
 524                         ret = -EACCES;
 525
 526                 if (ret < 0) {
 527                         dev_err(ispi->dev, "read error: %llx: %#x\n", from,
 528                                 status);
 529                         return ret;
 530                 }
 531
 532                 ret = intel_spi_read_block(ispi, read_buf, block_size);
 533                 if (ret)
 534                         return ret;
 535
 536                 len -= block_size;
 537                 from += block_size;
 538                 retlen += block_size;
 539                 read_buf += block_size;
 540         }
 541
 542         return retlen;
 543 }
 544
 545 static ssize_t intel_spi_write(struct spi_nor *nor, loff_t to, size_t len,
 546                                const u_char *write_buf)
 547 {
 548         struct intel_spi *ispi = nor->priv;
 549         size_t block_size, retlen = 0;
 550         u32 val, status;
 551         ssize_t ret;
 552
 553         while (len > 0) {
 554                 block_size = min_t(size_t, len, INTEL_SPI_FIFO_SZ);
 555
 556                 writel(to, ispi->base + FADDR);
 557
 558                 val = readl(ispi->base + HSFSTS_CTL);
 559                 val &= ~(HSFSTS_CTL_FDBC_MASK | HSFSTS_CTL_FCYCLE_MASK);
 560                 val |= HSFSTS_CTL_AEL | HSFSTS_CTL_FCERR | HSFSTS_CTL_FDONE;
 561                 val |= (block_size - 1) << HSFSTS_CTL_FDBC_SHIFT;
 562                 val |= HSFSTS_CTL_FCYCLE_WRITE;
 563
 564                 /* Write enable */
 565                 if (ispi->preopcodes[1] == SPINOR_OP_WREN)
 566                         val |= SSFSTS_CTL_SPOP;
 567                 val |= SSFSTS_CTL_ACS;
 568                 writel(val, ispi->base + HSFSTS_CTL);
 569
 570                 ret = intel_spi_write_block(ispi, write_buf, block_size);
 571                 if (ret) {
 572                         dev_err(ispi->dev, "failed to write block\n");
 573                         return ret;
 574                 }
 575
 576                 /* Start the write now */
 577                 val = readl(ispi->base + HSFSTS_CTL);
 578                 writel(val | HSFSTS_CTL_FGO, ispi->base + HSFSTS_CTL);
 579
 580                 ret = intel_spi_wait_hw_busy(ispi);
 581                 if (ret) {
 582                         dev_err(ispi->dev, "timeout\n");
 583                         return ret;
 584                 }
 585
 586                 status = readl(ispi->base + HSFSTS_CTL);
 587                 if (status & HSFSTS_CTL_FCERR)
 588                         ret = -EIO;
 589                 else if (status & HSFSTS_CTL_AEL)
 590                         ret = -EACCES;
 591
 592                 if (ret < 0) {
 593                         dev_err(ispi->dev, "write error: %llx: %#x\n", to,
 594                                 status);
 595                         return ret;
 596                 }
 597
 598                 len -= block_size;
 599                 to += block_size;
 600                 retlen += block_size;
 601                 write_buf += block_size;
 602         }
 603
 604         return retlen;
 605 }
 606
 607 static int intel_spi_erase(struct spi_nor *nor, loff_t offs)
 608 {
 609         size_t erase_size, len = nor->mtd.erasesize;
 610         struct intel_spi *ispi = nor->priv;
 611         u32 val, status, cmd;
 612         int ret;
 613
 614         /* If the hardware can do 64k erase use that when possible */
 615         if (len >= SZ_64K && ispi->erase_64k) {
 616                 cmd = HSFSTS_CTL_FCYCLE_ERASE_64K;
 617                 erase_size = SZ_64K;
 618         } else {
 619                 cmd = HSFSTS_CTL_FCYCLE_ERASE;
 620                 erase_size = SZ_4K;
 621         }
 622
 623         while (len > 0) {
 624                 writel(offs, ispi->base + FADDR);
 625
 626                 val = readl(ispi->base + HSFSTS_CTL);
 627                 val &= ~(HSFSTS_CTL_FDBC_MASK | HSFSTS_CTL_FCYCLE_MASK);
 628                 val |= HSFSTS_CTL_AEL | HSFSTS_CTL_FCERR | HSFSTS_CTL_FDONE;
 629                 val |= cmd;
 630                 val |= HSFSTS_CTL_FGO;
 631                 writel(val, ispi->base + HSFSTS_CTL);
 632
 633                 ret = intel_spi_wait_hw_busy(ispi);
 634                 if (ret)
 635                         return ret;
 636
 637                 status = readl(ispi->base + HSFSTS_CTL);
 638                 if (status & HSFSTS_CTL_FCERR)
 639                         return -EIO;
 640                 else if (status & HSFSTS_CTL_AEL)
 641                         return -EACCES;
 642
 643                 offs += erase_size;
 644                 len -= erase_size;
 645         }
 646
 647         return 0;
 648 }
 649
 650 static bool intel_spi_is_protected(const struct intel_spi *ispi,
 651                                    unsigned int base, unsigned int limit)
 652 {
 653         int i;
 654
 655         for (i = 0; i < PR_NUM; i++) {
 656                 u32 pr_base, pr_limit, pr_value;
 657
 658                 pr_value = readl(ispi->pregs + PR(i));
 659                 if (!(pr_value & (PR_WPE | PR_RPE)))
 660                         continue;
 661
 662                 pr_limit = (pr_value & PR_LIMIT_MASK) >> PR_LIMIT_SHIFT;
 663                 pr_base = pr_value & PR_BASE_MASK;
 664
 665                 if (pr_base >= base && pr_limit <= limit)
 666                         return true;
 667         }
 668
 669         return false;
 670 }
 671
 672 /*
 673  * There will be a single partition holding all enabled flash regions. We
 674  * call this "BIOS".
 675  */
 676 static void intel_spi_fill_partition(struct intel_spi *ispi,
 677                                      struct mtd_partition *part)
 678 {
 679         u64 end;
 680         int i;
 681
 682         memset(part, 0, sizeof(*part));
 683
 684         /* Start from the mandatory descriptor region */
 685         part->size = 4096;
 686         part->name = "BIOS";
 687
 688         /*
 689          * Now try to find where this partition ends based on the flash
 690          * region registers.
 691          */
 692         for (i = 1; i < ispi->nregions; i++) {
 693                 u32 region, base, limit;
 694
 695                 region = readl(ispi->base + FREG(i));
 696                 base = region & FREG_BASE_MASK;
 697                 limit = (region & FREG_LIMIT_MASK) >> FREG_LIMIT_SHIFT;
 698
 699                 if (base >= limit || limit == 0)
 700                         continue;
 701
 702                 /*
 703                  * If any of the regions have protection bits set, make the
 704                  * whole partition read-only to be on the safe side.
 705                  */
 706                 if (intel_spi_is_protected(ispi, base, limit))
 707                         ispi->writeable = 0;
 708
 709                 end = (limit << 12) + 4096;
 710                 if (end > part->size)
 711                         part->size = end;
 712         }
 713 }
 714
 715 struct intel_spi *intel_spi_probe(struct device *dev,
 716         struct resource *mem, const struct intel_spi_boardinfo *info)
 717 {
 718         struct mtd_partition part;
 719         struct intel_spi *ispi;
 720         int ret;
 721
 722         if (!info || !mem)
 723                 return ERR_PTR(-EINVAL);
 724
 725         ispi = devm_kzalloc(dev, sizeof(*ispi), GFP_KERNEL);
 726         if (!ispi)
 727                 return ERR_PTR(-ENOMEM);
 728
 729         ispi->base = devm_ioremap_resource(dev, mem);
 730         if (IS_ERR(ispi->base))
 731                 return ispi->base;
 732
 733         ispi->dev = dev;
 734         ispi->info = info;
 735         ispi->writeable = info->writeable;
 736
 737         ret = intel_spi_init(ispi);
 738         if (ret)
 739                 return ERR_PTR(ret);
 740
 741         ispi->nor.dev = ispi->dev;
 742         ispi->nor.priv = ispi;
 743         ispi->nor.read_reg = intel_spi_read_reg;
 744         ispi->nor.write_reg = intel_spi_write_reg;
 745         ispi->nor.read = intel_spi_read;
 746         ispi->nor.write = intel_spi_write;
 747         ispi->nor.erase = intel_spi_erase;
 748
 749         ret = spi_nor_scan(&ispi->nor, NULL, SPI_NOR_NORMAL);
 750         if (ret) {
 751                 dev_info(dev, "failed to locate the chip\n");
 752                 return ERR_PTR(ret);
 753         }
 754
 755         intel_spi_fill_partition(ispi, &part);
 756
 757         /* Prevent writes if not explicitly enabled */
 758         if (!ispi->writeable || !writeable)
 759                 ispi->nor.mtd.flags &= ~MTD_WRITEABLE;
 760
 761         ret = mtd_device_parse_register(&ispi->nor.mtd, NULL, NULL, &part, 1);
 762         if (ret)
 763                 return ERR_PTR(ret);
 764
 765         return ispi;
 766 }
 767 EXPORT_SYMBOL_GPL(intel_spi_probe);
 768
 769 int intel_spi_remove(struct intel_spi *ispi)
 770 {
 771         return mtd_device_unregister(&ispi->nor.mtd);
 772 }
 773 EXPORT_SYMBOL_GPL(intel_spi_remove);
 774
 775 MODULE_DESCRIPTION("Intel PCH/PCU SPI flash core driver");
 776 MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
 777 MODULE_LICENSE("GPL v2");