drivers/spi/spi-falcon.c

   1 /*
   2  *  This program is free software; you can redistribute it and/or modify it
   3  *  under the terms of the GNU General Public License version 2 as published
   4  *  by the Free Software Foundation.
   5  *
   6  *  Copyright (C) 2012 Thomas Langer <thomas.langer@lantiq.com>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/device.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/spi/spi.h>
  13 #include <linux/delay.h>
  14 #include <linux/workqueue.h>
  15 #include <linux/of.h>
  16 #include <linux/of_platform.h>
  17
  18 #include <lantiq_soc.h>
  19
  20 #define DRV_NAME                "sflash-falcon"
  21
  22 #define FALCON_SPI_XFER_BEGIN   (1 << 0)
  23 #define FALCON_SPI_XFER_END     (1 << 1)
  24
  25 /* Bus Read Configuration Register0 */
  26 #define BUSRCON0                0x00000010
  27 /* Bus Write Configuration Register0 */
  28 #define BUSWCON0                0x00000018
  29 /* Serial Flash Configuration Register */
  30 #define SFCON                   0x00000080
  31 /* Serial Flash Time Register */
  32 #define SFTIME                  0x00000084
  33 /* Serial Flash Status Register */
  34 #define SFSTAT                  0x00000088
  35 /* Serial Flash Command Register */
  36 #define SFCMD                   0x0000008C
  37 /* Serial Flash Address Register */
  38 #define SFADDR                  0x00000090
  39 /* Serial Flash Data Register */
  40 #define SFDATA                  0x00000094
  41 /* Serial Flash I/O Control Register */
  42 #define SFIO                    0x00000098
  43 /* EBU Clock Control Register */
  44 #define EBUCC                   0x000000C4
  45
  46 /* Dummy Phase Length */
  47 #define SFCMD_DUMLEN_OFFSET     16
  48 #define SFCMD_DUMLEN_MASK       0x000F0000
  49 /* Chip Select */
  50 #define SFCMD_CS_OFFSET         24
  51 #define SFCMD_CS_MASK           0x07000000
  52 /* field offset */
  53 #define SFCMD_ALEN_OFFSET       20
  54 #define SFCMD_ALEN_MASK         0x00700000
  55 /* SCK Rise-edge Position */
  56 #define SFTIME_SCKR_POS_OFFSET  8
  57 #define SFTIME_SCKR_POS_MASK    0x00000F00
  58 /* SCK Period */
  59 #define SFTIME_SCK_PER_OFFSET   0
  60 #define SFTIME_SCK_PER_MASK     0x0000000F
  61 /* SCK Fall-edge Position */
  62 #define SFTIME_SCKF_POS_OFFSET  12
  63 #define SFTIME_SCKF_POS_MASK    0x0000F000
  64 /* Device Size */
  65 #define SFCON_DEV_SIZE_A23_0    0x03000000
  66 #define SFCON_DEV_SIZE_MASK     0x0F000000
  67 /* Read Data Position */
  68 #define SFTIME_RD_POS_MASK      0x000F0000
  69 /* Data Output */
  70 #define SFIO_UNUSED_WD_MASK     0x0000000F
  71 /* Command Opcode mask */
  72 #define SFCMD_OPC_MASK          0x000000FF
  73 /* dlen bytes of data to write */
  74 #define SFCMD_DIR_WRITE         0x00000100
  75 /* Data Length offset */
  76 #define SFCMD_DLEN_OFFSET       9
  77 /* Command Error */
  78 #define SFSTAT_CMD_ERR          0x20000000
  79 /* Access Command Pending */
  80 #define SFSTAT_CMD_PEND         0x00400000
  81 /* Frequency set to 100MHz. */
  82 #define EBUCC_EBUDIV_SELF100    0x00000001
  83 /* Serial Flash */
  84 #define BUSRCON0_AGEN_SERIAL_FLASH      0xF0000000
  85 /* 8-bit multiplexed */
  86 #define BUSRCON0_PORTW_8_BIT_MUX        0x00000000
  87 /* Serial Flash */
  88 #define BUSWCON0_AGEN_SERIAL_FLASH      0xF0000000
  89 /* Chip Select after opcode */
  90 #define SFCMD_KEEP_CS_KEEP_SELECTED     0x00008000
  91
  92 #define CLOCK_100M      100000000
  93 #define CLOCK_50M       50000000
  94
  95 struct falcon_sflash {
  96         u32 sfcmd; /* for caching of opcode, direction, ... */
  97         struct spi_master *master;
  98 };
  99
 100 int falcon_sflash_xfer(struct spi_device *spi, struct spi_transfer *t,
 101                 unsigned long flags)
 102 {
 103         struct device *dev = &spi->dev;
 104         struct falcon_sflash *priv = spi_master_get_devdata(spi->master);
 105         const u8 *txp = t->tx_buf;
 106         u8 *rxp = t->rx_buf;
 107         unsigned int bytelen = ((8 * t->len + 7) / 8);
 108         unsigned int len, alen, dumlen;
 109         u32 val;
 110         enum {
 111                 state_init,
 112                 state_command_prepare,
 113                 state_write,
 114                 state_read,
 115                 state_disable_cs,
 116                 state_end
 117         } state = state_init;
 118
 119         do {
 120                 switch (state) {
 121                 case state_init: /* detect phase of upper layer sequence */
 122                 {
 123                         /* initial write ? */
 124                         if (flags & FALCON_SPI_XFER_BEGIN) {
 125                                 if (!txp) {
 126                                         dev_err(dev,
 127                                                 "BEGIN without tx data!\n");
 128                                         return -ENODATA;
 129                                 }
 130                                 /*
 131                                  * Prepare the parts of the sfcmd register,
 132                                  * which should not change during a sequence!
 133                                  * Only exception are the length fields,
 134                                  * especially alen and dumlen.
 135                                  */
 136
 137                                 priv->sfcmd = ((spi->chip_select
 138                                                 << SFCMD_CS_OFFSET)
 139                                                & SFCMD_CS_MASK);
 140                                 priv->sfcmd |= SFCMD_KEEP_CS_KEEP_SELECTED;
 141                                 priv->sfcmd |= *txp;
 142                                 txp++;
 143                                 bytelen--;
 144                                 if (bytelen) {
 145                                         /*
 146                                          * more data:
 147                                          * maybe address and/or dummy
 148                                          */
 149                                         state = state_command_prepare;
 150                                         break;
 151                                 } else {
 152                                         dev_dbg(dev, "write cmd %02X\n",
 153                                                 priv->sfcmd & SFCMD_OPC_MASK);
 154                                 }
 155                         }
 156                         /* continued write ? */
 157                         if (txp && bytelen) {
 158                                 state = state_write;
 159                                 break;
 160                         }
 161                         /* read data? */
 162                         if (rxp && bytelen) {
 163                                 state = state_read;
 164                                 break;
 165                         }
 166                         /* end of sequence? */
 167                         if (flags & FALCON_SPI_XFER_END)
 168                                 state = state_disable_cs;
 169                         else
 170                                 state = state_end;
 171                         break;
 172                 }
 173                 /* collect tx data for address and dummy phase */
 174                 case state_command_prepare:
 175                 {
 176                         /* txp is valid, already checked */
 177                         val = 0;
 178                         alen = 0;
 179                         dumlen = 0;
 180                         while (bytelen > 0) {
 181                                 if (alen < 3) {
 182                                         val = (val << 8) | (*txp++);
 183                                         alen++;
 184                                 } else if ((dumlen < 15) && (*txp == 0)) {
 185                                         /*
 186                                          * assume dummy bytes are set to 0
 187                                          * from upper layer
 188                                          */
 189                                         dumlen++;
 190                                         txp++;
 191                                 } else {
 192                                         break;
 193                                 }
 194                                 bytelen--;
 195                         }
 196                         priv->sfcmd &= ~(SFCMD_ALEN_MASK | SFCMD_DUMLEN_MASK);
 197                         priv->sfcmd |= (alen << SFCMD_ALEN_OFFSET) |
 198                                          (dumlen << SFCMD_DUMLEN_OFFSET);
 199                         if (alen > 0)
 200                                 ltq_ebu_w32(val, SFADDR);
 201
 202                         dev_dbg(dev, "wr %02X, alen=%d (addr=%06X) dlen=%d\n",
 203                                 priv->sfcmd & SFCMD_OPC_MASK,
 204                                 alen, val, dumlen);
 205
 206                         if (bytelen > 0) {
 207                                 /* continue with write */
 208                                 state = state_write;
 209                         } else if (flags & FALCON_SPI_XFER_END) {
 210                                 /* end of sequence? */
 211                                 state = state_disable_cs;
 212                         } else {
 213                                 /*
 214                                  * go to end and expect another
 215                                  * call (read or write)
 216                                  */
 217                                 state = state_end;
 218                         }
 219                         break;
 220                 }
 221                 case state_write:
 222                 {
 223                         /* txp still valid */
 224                         priv->sfcmd |= SFCMD_DIR_WRITE;
 225                         len = 0;
 226                         val = 0;
 227                         do {
 228                                 if (bytelen--)
 229                                         val |= (*txp++) << (8 * len++);
 230                                 if ((flags & FALCON_SPI_XFER_END)
 231                                     && (bytelen == 0)) {
 232                                         priv->sfcmd &=
 233                                                 ~SFCMD_KEEP_CS_KEEP_SELECTED;
 234                                 }
 235                                 if ((len == 4) || (bytelen == 0)) {
 236                                         ltq_ebu_w32(val, SFDATA);
 237                                         ltq_ebu_w32(priv->sfcmd
 238                                                 | (len<<SFCMD_DLEN_OFFSET),
 239                                                 SFCMD);
 240                                         len = 0;
 241                                         val = 0;
 242                                         priv->sfcmd &= ~(SFCMD_ALEN_MASK
 243                                                          | SFCMD_DUMLEN_MASK);
 244                                 }
 245                         } while (bytelen);
 246                         state = state_end;
 247                         break;
 248                 }
 249                 case state_read:
 250                 {
 251                         /* read data */
 252                         priv->sfcmd &= ~SFCMD_DIR_WRITE;
 253                         do {
 254                                 if ((flags & FALCON_SPI_XFER_END)
 255                                     && (bytelen <= 4)) {
 256                                         priv->sfcmd &=
 257                                                 ~SFCMD_KEEP_CS_KEEP_SELECTED;
 258                                 }
 259                                 len = (bytelen > 4) ? 4 : bytelen;
 260                                 bytelen -= len;
 261                                 ltq_ebu_w32(priv->sfcmd
 262                                         | (len << SFCMD_DLEN_OFFSET), SFCMD);
 263                                 priv->sfcmd &= ~(SFCMD_ALEN_MASK
 264                                                  | SFCMD_DUMLEN_MASK);
 265                                 do {
 266                                         val = ltq_ebu_r32(SFSTAT);
 267                                         if (val & SFSTAT_CMD_ERR) {
 268                                                 /* reset error status */
 269                                                 dev_err(dev, "SFSTAT: CMD_ERR");
 270                                                 dev_err(dev, " (%x)\n", val);
 271                                                 ltq_ebu_w32(SFSTAT_CMD_ERR,
 272                                                         SFSTAT);
 273                                                 return -EBADE;
 274                                         }
 275                                 } while (val & SFSTAT_CMD_PEND);
 276                                 val = ltq_ebu_r32(SFDATA);
 277                                 do {
 278                                         *rxp = (val & 0xFF);
 279                                         rxp++;
 280                                         val >>= 8;
 281                                         len--;
 282                                 } while (len);
 283                         } while (bytelen);
 284                         state = state_end;
 285                         break;
 286                 }
 287                 case state_disable_cs:
 288                 {
 289                         priv->sfcmd &= ~SFCMD_KEEP_CS_KEEP_SELECTED;
 290                         ltq_ebu_w32(priv->sfcmd | (0 << SFCMD_DLEN_OFFSET),
 291                                 SFCMD);
 292                         val = ltq_ebu_r32(SFSTAT);
 293                         if (val & SFSTAT_CMD_ERR) {
 294                                 /* reset error status */
 295                                 dev_err(dev, "SFSTAT: CMD_ERR (%x)\n", val);
 296                                 ltq_ebu_w32(SFSTAT_CMD_ERR, SFSTAT);
 297                                 return -EBADE;
 298                         }
 299                         state = state_end;
 300                         break;
 301                 }
 302                 case state_end:
 303                         break;
 304                 }
 305         } while (state != state_end);
 306
 307         return 0;
 308 }
 309
 310 static int falcon_sflash_setup(struct spi_device *spi)
 311 {
 312         unsigned int i;
 313         unsigned long flags;
 314
 315         spin_lock_irqsave(&ebu_lock, flags);
 316
 317         if (spi->max_speed_hz >= CLOCK_100M) {
 318                 /* set EBU clock to 100 MHz */
 319                 ltq_sys1_w32_mask(0, EBUCC_EBUDIV_SELF100, EBUCC);
 320                 i = 1; /* divider */
 321         } else {
 322                 /* set EBU clock to 50 MHz */
 323                 ltq_sys1_w32_mask(EBUCC_EBUDIV_SELF100, 0, EBUCC);
 324
 325                 /* search for suitable divider */
 326                 for (i = 1; i < 7; i++) {
 327                         if (CLOCK_50M / i <= spi->max_speed_hz)
 328                                 break;
 329                 }
 330         }
 331
 332         /* setup period of serial clock */
 333         ltq_ebu_w32_mask(SFTIME_SCKF_POS_MASK
 334                      | SFTIME_SCKR_POS_MASK
 335                      | SFTIME_SCK_PER_MASK,
 336                      (i << SFTIME_SCKR_POS_OFFSET)
 337                      | (i << (SFTIME_SCK_PER_OFFSET + 1)),
 338                      SFTIME);
 339
 340         /*
 341          * set some bits of unused_wd, to not trigger HOLD/WP
 342          * signals on non QUAD flashes
 343          */
 344         ltq_ebu_w32((SFIO_UNUSED_WD_MASK & (0x8 | 0x4)), SFIO);
 345
 346         ltq_ebu_w32(BUSRCON0_AGEN_SERIAL_FLASH | BUSRCON0_PORTW_8_BIT_MUX,
 347                         BUSRCON0);
 348         ltq_ebu_w32(BUSWCON0_AGEN_SERIAL_FLASH, BUSWCON0);
 349         /* set address wrap around to maximum for 24-bit addresses */
 350         ltq_ebu_w32_mask(SFCON_DEV_SIZE_MASK, SFCON_DEV_SIZE_A23_0, SFCON);
 351
 352         spin_unlock_irqrestore(&ebu_lock, flags);
 353
 354         return 0;
 355 }
 356
 357 static int falcon_sflash_prepare_xfer(struct spi_master *master)
 358 {
 359         return 0;
 360 }
 361
 362 static int falcon_sflash_unprepare_xfer(struct spi_master *master)
 363 {
 364         return 0;
 365 }
 366
 367 static int falcon_sflash_xfer_one(struct spi_master *master,
 368                                         struct spi_message *m)
 369 {
 370         struct falcon_sflash *priv = spi_master_get_devdata(master);
 371         struct spi_transfer *t;
 372         unsigned long spi_flags;
 373         unsigned long flags;
 374         int ret = 0;
 375
 376         priv->sfcmd = 0;
 377         m->actual_length = 0;
 378
 379         spi_flags = FALCON_SPI_XFER_BEGIN;
 380         list_for_each_entry(t, &m->transfers, transfer_list) {
 381                 if (list_is_last(&t->transfer_list, &m->transfers))
 382                         spi_flags |= FALCON_SPI_XFER_END;
 383
 384                 spin_lock_irqsave(&ebu_lock, flags);
 385                 ret = falcon_sflash_xfer(m->spi, t, spi_flags);
 386                 spin_unlock_irqrestore(&ebu_lock, flags);
 387
 388                 if (ret)
 389                         break;
 390
 391                 m->actual_length += t->len;
 392
 393                 WARN_ON(t->delay_usecs || t->cs_change);
 394                 spi_flags = 0;
 395         }
 396
 397         m->status = ret;
 398         spi_finalize_current_message(master);
 399
 400         return 0;
 401 }
 402
 403 static int falcon_sflash_probe(struct platform_device *pdev)
 404 {
 405         struct falcon_sflash *priv;
 406         struct spi_master *master;
 407         int ret;
 408
 409         if (ltq_boot_select() != BS_SPI) {
 410                 dev_err(&pdev->dev, "invalid bootstrap options\n");
 411                 return -ENODEV;
 412         }
 413
 414         master = spi_alloc_master(&pdev->dev, sizeof(*priv));
 415         if (!master)
 416                 return -ENOMEM;
 417
 418         priv = spi_master_get_devdata(master);
 419         priv->master = master;
 420
 421         master->mode_bits = SPI_MODE_3;
 422         master->flags = SPI_MASTER_HALF_DUPLEX;
 423         master->setup = falcon_sflash_setup;
 424         master->prepare_transfer_hardware = falcon_sflash_prepare_xfer;
 425         master->transfer_one_message = falcon_sflash_xfer_one;
 426         master->unprepare_transfer_hardware = falcon_sflash_unprepare_xfer;
 427         master->dev.of_node = pdev->dev.of_node;
 428
 429         platform_set_drvdata(pdev, priv);
 430
 431         ret = devm_spi_register_master(&pdev->dev, master);
 432         if (ret)
 433                 spi_master_put(master);
 434         return ret;
 435 }
 436
 437 static const struct of_device_id falcon_sflash_match[] = {
 438         { .compatible = "lantiq,sflash-falcon" },
 439         {},
 440 };
 441 MODULE_DEVICE_TABLE(of, falcon_sflash_match);
 442
 443 static struct platform_driver falcon_sflash_driver = {
 444         .probe  = falcon_sflash_probe,
 445         .driver = {
 446                 .name   = DRV_NAME,
 447                 .owner  = THIS_MODULE,
 448                 .of_match_table = falcon_sflash_match,
 449         }
 450 };
 451
 452 module_platform_driver(falcon_sflash_driver);
 453
 454 MODULE_LICENSE("GPL");
 455 MODULE_DESCRIPTION("Lantiq Falcon SPI/SFLASH controller driver");