drivers/spi/au1550_spi.c

   1 /*
   2  * au1550_spi.c - au1550 psc spi controller driver
   3  * may work also with au1200, au1210, au1250
   4  * will not work on au1000, au1100 and au1500 (no full spi controller there)
   5  *
   6  * Copyright (c) 2006 ATRON electronic GmbH
   7  * Author: Jan Nikitenko <jan.nikitenko@gmail.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22  */
  23
  24 #include <linux/init.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/errno.h>
  27 #include <linux/device.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/resource.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/spi/spi_bitbang.h>
  32 #include <linux/dma-mapping.h>
  33 #include <linux/completion.h>
  34 #include <asm/mach-au1x00/au1000.h>
  35 #include <asm/mach-au1x00/au1xxx_psc.h>
  36 #include <asm/mach-au1x00/au1xxx_dbdma.h>
  37
  38 #include <asm/mach-au1x00/au1550_spi.h>
  39
  40 static unsigned usedma = 1;
  41 module_param(usedma, uint, 0644);
  42
  43 /*
  44 #define AU1550_SPI_DEBUG_LOOPBACK
  45 */
  46
  47
  48 #define AU1550_SPI_DBDMA_DESCRIPTORS 1
  49 #define AU1550_SPI_DMA_RXTMP_MINSIZE 2048U
  50
  51 struct au1550_spi {
  52         struct spi_bitbang bitbang;
  53
  54         volatile psc_spi_t __iomem *regs;
  55         int irq;
  56         unsigned freq_max;
  57         unsigned freq_min;
  58
  59         unsigned len;
  60         unsigned tx_count;
  61         unsigned rx_count;
  62         const u8 *tx;
  63         u8 *rx;
  64
  65         void (*rx_word)(struct au1550_spi *hw);
  66         void (*tx_word)(struct au1550_spi *hw);
  67         int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
  68         irqreturn_t (*irq_callback)(struct au1550_spi *hw);
  69
  70         struct completion master_done;
  71
  72         unsigned usedma;
  73         u32 dma_tx_id;
  74         u32 dma_rx_id;
  75         u32 dma_tx_ch;
  76         u32 dma_rx_ch;
  77
  78         u8 *dma_rx_tmpbuf;
  79         unsigned dma_rx_tmpbuf_size;
  80         u32 dma_rx_tmpbuf_addr;
  81
  82         struct spi_master *master;
  83         struct device *dev;
  84         struct au1550_spi_info *pdata;
  85         struct resource *ioarea;
  86 };
  87
  88
  89 /* we use an 8-bit memory device for dma transfers to/from spi fifo */
  90 static dbdev_tab_t au1550_spi_mem_dbdev =
  91 {
  92         .dev_id                 = DBDMA_MEM_CHAN,
  93         .dev_flags              = DEV_FLAGS_ANYUSE|DEV_FLAGS_SYNC,
  94         .dev_tsize              = 0,
  95         .dev_devwidth           = 8,
  96         .dev_physaddr           = 0x00000000,
  97         .dev_intlevel           = 0,
  98         .dev_intpolarity        = 0
  99 };
 100
 101 static int ddma_memid;  /* id to above mem dma device */
 102
 103 static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw);
 104
 105
 106 /*
 107  *  compute BRG and DIV bits to setup spi clock based on main input clock rate
 108  *  that was specified in platform data structure
 109  *  according to au1550 datasheet:
 110  *    psc_tempclk = psc_mainclk / (2 << DIV)
 111  *    spiclk = psc_tempclk / (2 * (BRG + 1))
 112  *    BRG valid range is 4..63
 113  *    DIV valid range is 0..3
 114  */
 115 static u32 au1550_spi_baudcfg(struct au1550_spi *hw, unsigned speed_hz)
 116 {
 117         u32 mainclk_hz = hw->pdata->mainclk_hz;
 118         u32 div, brg;
 119
 120         for (div = 0; div < 4; div++) {
 121                 brg = mainclk_hz / speed_hz / (4 << div);
 122                 /* now we have BRG+1 in brg, so count with that */
 123                 if (brg < (4 + 1)) {
 124                         brg = (4 + 1);  /* speed_hz too big */
 125                         break;          /* set lowest brg (div is == 0) */
 126                 }
 127                 if (brg <= (63 + 1))
 128                         break;          /* we have valid brg and div */
 129         }
 130         if (div == 4) {
 131                 div = 3;                /* speed_hz too small */
 132                 brg = (63 + 1);         /* set highest brg and div */
 133         }
 134         brg--;
 135         return PSC_SPICFG_SET_BAUD(brg) | PSC_SPICFG_SET_DIV(div);
 136 }
 137
 138 static inline void au1550_spi_mask_ack_all(struct au1550_spi *hw)
 139 {
 140         hw->regs->psc_spimsk =
 141                   PSC_SPIMSK_MM | PSC_SPIMSK_RR | PSC_SPIMSK_RO
 142                 | PSC_SPIMSK_RU | PSC_SPIMSK_TR | PSC_SPIMSK_TO
 143                 | PSC_SPIMSK_TU | PSC_SPIMSK_SD | PSC_SPIMSK_MD;
 144         au_sync();
 145
 146         hw->regs->psc_spievent =
 147                   PSC_SPIEVNT_MM | PSC_SPIEVNT_RR | PSC_SPIEVNT_RO
 148                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TR | PSC_SPIEVNT_TO
 149                 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD | PSC_SPIEVNT_MD;
 150         au_sync();
 151 }
 152
 153 static void au1550_spi_reset_fifos(struct au1550_spi *hw)
 154 {
 155         u32 pcr;
 156
 157         hw->regs->psc_spipcr = PSC_SPIPCR_RC | PSC_SPIPCR_TC;
 158         au_sync();
 159         do {
 160                 pcr = hw->regs->psc_spipcr;
 161                 au_sync();
 162         } while (pcr != 0);
 163 }
 164
 165 /*
 166  * dma transfers are used for the most common spi word size of 8-bits
 167  * we cannot easily change already set up dma channels' width, so if we wanted
 168  * dma support for more than 8-bit words (up to 24 bits), we would need to
 169  * setup dma channels from scratch on each spi transfer, based on bits_per_word
 170  * instead we have pre set up 8 bit dma channels supporting spi 4 to 8 bits
 171  * transfers, and 9 to 24 bits spi transfers will be done in pio irq based mode
 172  * callbacks to handle dma or pio are set up in au1550_spi_bits_handlers_set()
 173  */
 174 static void au1550_spi_chipsel(struct spi_device *spi, int value)
 175 {
 176         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 177         unsigned cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
 178         u32 cfg, stat;
 179
 180         switch (value) {
 181         case BITBANG_CS_INACTIVE:
 182                 if (hw->pdata->deactivate_cs)
 183                         hw->pdata->deactivate_cs(hw->pdata, spi->chip_select,
 184                                         cspol);
 185                 break;
 186
 187         case BITBANG_CS_ACTIVE:
 188                 au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
 189
 190                 cfg = hw->regs->psc_spicfg;
 191                 au_sync();
 192                 hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
 193                 au_sync();
 194
 195                 if (spi->mode & SPI_CPOL)
 196                         cfg |= PSC_SPICFG_BI;
 197                 else
 198                         cfg &= ~PSC_SPICFG_BI;
 199                 if (spi->mode & SPI_CPHA)
 200                         cfg &= ~PSC_SPICFG_CDE;
 201                 else
 202                         cfg |= PSC_SPICFG_CDE;
 203
 204                 if (spi->mode & SPI_LSB_FIRST)
 205                         cfg |= PSC_SPICFG_MLF;
 206                 else
 207                         cfg &= ~PSC_SPICFG_MLF;
 208
 209                 if (hw->usedma && spi->bits_per_word <= 8)
 210                         cfg &= ~PSC_SPICFG_DD_DISABLE;
 211                 else
 212                         cfg |= PSC_SPICFG_DD_DISABLE;
 213                 cfg = PSC_SPICFG_CLR_LEN(cfg);
 214                 cfg |= PSC_SPICFG_SET_LEN(spi->bits_per_word);
 215
 216                 cfg = PSC_SPICFG_CLR_BAUD(cfg);
 217                 cfg &= ~PSC_SPICFG_SET_DIV(3);
 218                 cfg |= au1550_spi_baudcfg(hw, spi->max_speed_hz);
 219
 220                 hw->regs->psc_spicfg = cfg | PSC_SPICFG_DE_ENABLE;
 221                 au_sync();
 222                 do {
 223                         stat = hw->regs->psc_spistat;
 224                         au_sync();
 225                 } while ((stat & PSC_SPISTAT_DR) == 0);
 226
 227                 if (hw->pdata->activate_cs)
 228                         hw->pdata->activate_cs(hw->pdata, spi->chip_select,
 229                                         cspol);
 230                 break;
 231         }
 232 }
 233
 234 static int au1550_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
 235 {
 236         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 237         unsigned bpw, hz;
 238         u32 cfg, stat;
 239
 240         bpw = t ? t->bits_per_word : spi->bits_per_word;
 241         hz = t ? t->speed_hz : spi->max_speed_hz;
 242
 243         if (bpw < 4 || bpw > 24) {
 244                 dev_err(&spi->dev, "setupxfer: invalid bits_per_word=%d\n",
 245                         bpw);
 246                 return -EINVAL;
 247         }
 248         if (hz > spi->max_speed_hz || hz > hw->freq_max || hz < hw->freq_min) {
 249                 dev_err(&spi->dev, "setupxfer: clock rate=%d out of range\n",
 250                         hz);
 251                 return -EINVAL;
 252         }
 253
 254         au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
 255
 256         cfg = hw->regs->psc_spicfg;
 257         au_sync();
 258         hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
 259         au_sync();
 260
 261         if (hw->usedma && bpw <= 8)
 262                 cfg &= ~PSC_SPICFG_DD_DISABLE;
 263         else
 264                 cfg |= PSC_SPICFG_DD_DISABLE;
 265         cfg = PSC_SPICFG_CLR_LEN(cfg);
 266         cfg |= PSC_SPICFG_SET_LEN(bpw);
 267
 268         cfg = PSC_SPICFG_CLR_BAUD(cfg);
 269         cfg &= ~PSC_SPICFG_SET_DIV(3);
 270         cfg |= au1550_spi_baudcfg(hw, hz);
 271
 272         hw->regs->psc_spicfg = cfg;
 273         au_sync();
 274
 275         if (cfg & PSC_SPICFG_DE_ENABLE) {
 276                 do {
 277                         stat = hw->regs->psc_spistat;
 278                         au_sync();
 279                 } while ((stat & PSC_SPISTAT_DR) == 0);
 280         }
 281
 282         au1550_spi_reset_fifos(hw);
 283         au1550_spi_mask_ack_all(hw);
 284         return 0;
 285 }
 286
 287 /* the spi->mode bits understood by this driver: */
 288 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST)
 289
 290 static int au1550_spi_setup(struct spi_device *spi)
 291 {
 292         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 293
 294         if (spi->bits_per_word == 0)
 295                 spi->bits_per_word = 8;
 296         if (spi->bits_per_word < 4 || spi->bits_per_word > 24) {
 297                 dev_err(&spi->dev, "setup: invalid bits_per_word=%d\n",
 298                         spi->bits_per_word);
 299                 return -EINVAL;
 300         }
 301
 302         if (spi->mode & ~MODEBITS) {
 303                 dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
 304                         spi->mode & ~MODEBITS);
 305                 return -EINVAL;
 306         }
 307
 308         if (spi->max_speed_hz == 0)
 309                 spi->max_speed_hz = hw->freq_max;
 310         if (spi->max_speed_hz > hw->freq_max
 311                         || spi->max_speed_hz < hw->freq_min)
 312                 return -EINVAL;
 313         /*
 314          * NOTE: cannot change speed and other hw settings immediately,
 315          *       otherwise sharing of spi bus is not possible,
 316          *       so do not call setupxfer(spi, NULL) here
 317          */
 318         return 0;
 319 }
 320
 321 /*
 322  * for dma spi transfers, we have to setup rx channel, otherwise there is
 323  * no reliable way how to recognize that spi transfer is done
 324  * dma complete callbacks are called before real spi transfer is finished
 325  * and if only tx dma channel is set up (and rx fifo overflow event masked)
 326  * spi master done event irq is not generated unless rx fifo is empty (emptied)
 327  * so we need rx tmp buffer to use for rx dma if user does not provide one
 328  */
 329 static int au1550_spi_dma_rxtmp_alloc(struct au1550_spi *hw, unsigned size)
 330 {
 331         hw->dma_rx_tmpbuf = kmalloc(size, GFP_KERNEL);
 332         if (!hw->dma_rx_tmpbuf)
 333                 return -ENOMEM;
 334         hw->dma_rx_tmpbuf_size = size;
 335         hw->dma_rx_tmpbuf_addr = dma_map_single(hw->dev, hw->dma_rx_tmpbuf,
 336                         size, DMA_FROM_DEVICE);
 337         if (dma_mapping_error(hw->dev, hw->dma_rx_tmpbuf_addr)) {
 338                 kfree(hw->dma_rx_tmpbuf);
 339                 hw->dma_rx_tmpbuf = 0;
 340                 hw->dma_rx_tmpbuf_size = 0;
 341                 return -EFAULT;
 342         }
 343         return 0;
 344 }
 345
 346 static void au1550_spi_dma_rxtmp_free(struct au1550_spi *hw)
 347 {
 348         dma_unmap_single(hw->dev, hw->dma_rx_tmpbuf_addr,
 349                         hw->dma_rx_tmpbuf_size, DMA_FROM_DEVICE);
 350         kfree(hw->dma_rx_tmpbuf);
 351         hw->dma_rx_tmpbuf = 0;
 352         hw->dma_rx_tmpbuf_size = 0;
 353 }
 354
 355 static int au1550_spi_dma_txrxb(struct spi_device *spi, struct spi_transfer *t)
 356 {
 357         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 358         dma_addr_t dma_tx_addr;
 359         dma_addr_t dma_rx_addr;
 360         u32 res;
 361
 362         hw->len = t->len;
 363         hw->tx_count = 0;
 364         hw->rx_count = 0;
 365
 366         hw->tx = t->tx_buf;
 367         hw->rx = t->rx_buf;
 368         dma_tx_addr = t->tx_dma;
 369         dma_rx_addr = t->rx_dma;
 370
 371         /*
 372          * check if buffers are already dma mapped, map them otherwise
 373          * use rx buffer in place of tx if tx buffer was not provided
 374          * use temp rx buffer (preallocated or realloc to fit) for rx dma
 375          */
 376         if (t->rx_buf) {
 377                 if (t->rx_dma == 0) {   /* if DMA_ADDR_INVALID, map it */
 378                         dma_rx_addr = dma_map_single(hw->dev,
 379                                         (void *)t->rx_buf,
 380                                         t->len, DMA_FROM_DEVICE);
 381                         if (dma_mapping_error(hw->dev, dma_rx_addr))
 382                                 dev_err(hw->dev, "rx dma map error\n");
 383                 }
 384         } else {
 385                 if (t->len > hw->dma_rx_tmpbuf_size) {
 386                         int ret;
 387
 388                         au1550_spi_dma_rxtmp_free(hw);
 389                         ret = au1550_spi_dma_rxtmp_alloc(hw, max(t->len,
 390                                         AU1550_SPI_DMA_RXTMP_MINSIZE));
 391                         if (ret < 0)
 392                                 return ret;
 393                 }
 394                 hw->rx = hw->dma_rx_tmpbuf;
 395                 dma_rx_addr = hw->dma_rx_tmpbuf_addr;
 396                 dma_sync_single_for_device(hw->dev, dma_rx_addr,
 397                         t->len, DMA_FROM_DEVICE);
 398         }
 399         if (t->tx_buf) {
 400                 if (t->tx_dma == 0) {   /* if DMA_ADDR_INVALID, map it */
 401                         dma_tx_addr = dma_map_single(hw->dev,
 402                                         (void *)t->tx_buf,
 403                                         t->len, DMA_TO_DEVICE);
 404                         if (dma_mapping_error(hw->dev, dma_tx_addr))
 405                                 dev_err(hw->dev, "tx dma map error\n");
 406                 }
 407         } else {
 408                 dma_sync_single_for_device(hw->dev, dma_rx_addr,
 409                                 t->len, DMA_BIDIRECTIONAL);
 410                 hw->tx = hw->rx;
 411         }
 412
 413         /* put buffers on the ring */
 414         res = au1xxx_dbdma_put_dest(hw->dma_rx_ch, hw->rx, t->len);
 415         if (!res)
 416                 dev_err(hw->dev, "rx dma put dest error\n");
 417
 418         res = au1xxx_dbdma_put_source(hw->dma_tx_ch, (void *)hw->tx, t->len);
 419         if (!res)
 420                 dev_err(hw->dev, "tx dma put source error\n");
 421
 422         au1xxx_dbdma_start(hw->dma_rx_ch);
 423         au1xxx_dbdma_start(hw->dma_tx_ch);
 424
 425         /* by default enable nearly all events interrupt */
 426         hw->regs->psc_spimsk = PSC_SPIMSK_SD;
 427         au_sync();
 428
 429         /* start the transfer */
 430         hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 431         au_sync();
 432
 433         wait_for_completion(&hw->master_done);
 434
 435         au1xxx_dbdma_stop(hw->dma_tx_ch);
 436         au1xxx_dbdma_stop(hw->dma_rx_ch);
 437
 438         if (!t->rx_buf) {
 439                 /* using the temporal preallocated and premapped buffer */
 440                 dma_sync_single_for_cpu(hw->dev, dma_rx_addr, t->len,
 441                         DMA_FROM_DEVICE);
 442         }
 443         /* unmap buffers if mapped above */
 444         if (t->rx_buf && t->rx_dma == 0 )
 445                 dma_unmap_single(hw->dev, dma_rx_addr, t->len,
 446                         DMA_FROM_DEVICE);
 447         if (t->tx_buf && t->tx_dma == 0 )
 448                 dma_unmap_single(hw->dev, dma_tx_addr, t->len,
 449                         DMA_TO_DEVICE);
 450
 451         return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
 452 }
 453
 454 static irqreturn_t au1550_spi_dma_irq_callback(struct au1550_spi *hw)
 455 {
 456         u32 stat, evnt;
 457
 458         stat = hw->regs->psc_spistat;
 459         evnt = hw->regs->psc_spievent;
 460         au_sync();
 461         if ((stat & PSC_SPISTAT_DI) == 0) {
 462                 dev_err(hw->dev, "Unexpected IRQ!\n");
 463                 return IRQ_NONE;
 464         }
 465
 466         if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
 467                                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
 468                                 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD))
 469                         != 0) {
 470                 /*
 471                  * due to an spi error we consider transfer as done,
 472                  * so mask all events until before next transfer start
 473                  * and stop the possibly running dma immediatelly
 474                  */
 475                 au1550_spi_mask_ack_all(hw);
 476                 au1xxx_dbdma_stop(hw->dma_rx_ch);
 477                 au1xxx_dbdma_stop(hw->dma_tx_ch);
 478
 479                 /* get number of transfered bytes */
 480                 hw->rx_count = hw->len - au1xxx_get_dma_residue(hw->dma_rx_ch);
 481                 hw->tx_count = hw->len - au1xxx_get_dma_residue(hw->dma_tx_ch);
 482
 483                 au1xxx_dbdma_reset(hw->dma_rx_ch);
 484                 au1xxx_dbdma_reset(hw->dma_tx_ch);
 485                 au1550_spi_reset_fifos(hw);
 486
 487                 if (evnt == PSC_SPIEVNT_RO)
 488                         dev_err(hw->dev,
 489                                 "dma transfer: receive FIFO overflow!\n");
 490                 else
 491                         dev_err(hw->dev,
 492                                 "dma transfer: unexpected SPI error "
 493                                 "(event=0x%x stat=0x%x)!\n", evnt, stat);
 494
 495                 complete(&hw->master_done);
 496                 return IRQ_HANDLED;
 497         }
 498
 499         if ((evnt & PSC_SPIEVNT_MD) != 0) {
 500                 /* transfer completed successfully */
 501                 au1550_spi_mask_ack_all(hw);
 502                 hw->rx_count = hw->len;
 503                 hw->tx_count = hw->len;
 504                 complete(&hw->master_done);
 505         }
 506         return IRQ_HANDLED;
 507 }
 508
 509
 510 /* routines to handle different word sizes in pio mode */
 511 #define AU1550_SPI_RX_WORD(size, mask)                                  \
 512 static void au1550_spi_rx_word_##size(struct au1550_spi *hw)            \
 513 {                                                                       \
 514         u32 fifoword = hw->regs->psc_spitxrx & (u32)(mask);             \
 515         au_sync();                                                      \
 516         if (hw->rx) {                                                   \
 517                 *(u##size *)hw->rx = (u##size)fifoword;                 \
 518                 hw->rx += (size) / 8;                                   \
 519         }                                                               \
 520         hw->rx_count += (size) / 8;                                     \
 521 }
 522
 523 #define AU1550_SPI_TX_WORD(size, mask)                                  \
 524 static void au1550_spi_tx_word_##size(struct au1550_spi *hw)            \
 525 {                                                                       \
 526         u32 fifoword = 0;                                               \
 527         if (hw->tx) {                                                   \
 528                 fifoword = *(u##size *)hw->tx & (u32)(mask);            \
 529                 hw->tx += (size) / 8;                                   \
 530         }                                                               \
 531         hw->tx_count += (size) / 8;                                     \
 532         if (hw->tx_count >= hw->len)                                    \
 533                 fifoword |= PSC_SPITXRX_LC;                             \
 534         hw->regs->psc_spitxrx = fifoword;                               \
 535         au_sync();                                                      \
 536 }
 537
 538 AU1550_SPI_RX_WORD(8,0xff)
 539 AU1550_SPI_RX_WORD(16,0xffff)
 540 AU1550_SPI_RX_WORD(32,0xffffff)
 541 AU1550_SPI_TX_WORD(8,0xff)
 542 AU1550_SPI_TX_WORD(16,0xffff)
 543 AU1550_SPI_TX_WORD(32,0xffffff)
 544
 545 static int au1550_spi_pio_txrxb(struct spi_device *spi, struct spi_transfer *t)
 546 {
 547         u32 stat, mask;
 548         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 549
 550         hw->tx = t->tx_buf;
 551         hw->rx = t->rx_buf;
 552         hw->len = t->len;
 553         hw->tx_count = 0;
 554         hw->rx_count = 0;
 555
 556         /* by default enable nearly all events after filling tx fifo */
 557         mask = PSC_SPIMSK_SD;
 558
 559         /* fill the transmit FIFO */
 560         while (hw->tx_count < hw->len) {
 561
 562                 hw->tx_word(hw);
 563
 564                 if (hw->tx_count >= hw->len) {
 565                         /* mask tx fifo request interrupt as we are done */
 566                         mask |= PSC_SPIMSK_TR;
 567                 }
 568
 569                 stat = hw->regs->psc_spistat;
 570                 au_sync();
 571                 if (stat & PSC_SPISTAT_TF)
 572                         break;
 573         }
 574
 575         /* enable event interrupts */
 576         hw->regs->psc_spimsk = mask;
 577         au_sync();
 578
 579         /* start the transfer */
 580         hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 581         au_sync();
 582
 583         wait_for_completion(&hw->master_done);
 584
 585         return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
 586 }
 587
 588 static irqreturn_t au1550_spi_pio_irq_callback(struct au1550_spi *hw)
 589 {
 590         int busy;
 591         u32 stat, evnt;
 592
 593         stat = hw->regs->psc_spistat;
 594         evnt = hw->regs->psc_spievent;
 595         au_sync();
 596         if ((stat & PSC_SPISTAT_DI) == 0) {
 597                 dev_err(hw->dev, "Unexpected IRQ!\n");
 598                 return IRQ_NONE;
 599         }
 600
 601         if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
 602                                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
 603                                 | PSC_SPIEVNT_SD))
 604                         != 0) {
 605                 /*
 606                  * due to an error we consider transfer as done,
 607                  * so mask all events until before next transfer start
 608                  */
 609                 au1550_spi_mask_ack_all(hw);
 610                 au1550_spi_reset_fifos(hw);
 611                 dev_err(hw->dev,
 612                         "pio transfer: unexpected SPI error "
 613                         "(event=0x%x stat=0x%x)!\n", evnt, stat);
 614                 complete(&hw->master_done);
 615                 return IRQ_HANDLED;
 616         }
 617
 618         /*
 619          * while there is something to read from rx fifo
 620          * or there is a space to write to tx fifo:
 621          */
 622         do {
 623                 busy = 0;
 624                 stat = hw->regs->psc_spistat;
 625                 au_sync();
 626
 627                 /*
 628                  * Take care to not let the Rx FIFO overflow.
 629                  *
 630                  * We only write a byte if we have read one at least. Initially,
 631                  * the write fifo is full, so we should read from the read fifo
 632                  * first.
 633                  * In case we miss a word from the read fifo, we should get a
 634                  * RO event and should back out.
 635                  */
 636                 if (!(stat & PSC_SPISTAT_RE) && hw->rx_count < hw->len) {
 637                         hw->rx_word(hw);
 638                         busy = 1;
 639
 640                         if (!(stat & PSC_SPISTAT_TF) && hw->tx_count < hw->len)
 641                                 hw->tx_word(hw);
 642                 }
 643         } while (busy);
 644
 645         hw->regs->psc_spievent = PSC_SPIEVNT_RR | PSC_SPIEVNT_TR;
 646         au_sync();
 647
 648         /*
 649          * Restart the SPI transmission in case of a transmit underflow.
 650          * This seems to work despite the notes in the Au1550 data book
 651          * of Figure 8-4 with flowchart for SPI master operation:
 652          *
 653          * """Note 1: An XFR Error Interrupt occurs, unless masked,
 654          * for any of the following events: Tx FIFO Underflow,
 655          * Rx FIFO Overflow, or Multiple-master Error
 656          *    Note 2: In case of a Tx Underflow Error, all zeroes are
 657          * transmitted."""
 658          *
 659          * By simply restarting the spi transfer on Tx Underflow Error,
 660          * we assume that spi transfer was paused instead of zeroes
 661          * transmittion mentioned in the Note 2 of Au1550 data book.
 662          */
 663         if (evnt & PSC_SPIEVNT_TU) {
 664                 hw->regs->psc_spievent = PSC_SPIEVNT_TU | PSC_SPIEVNT_MD;
 665                 au_sync();
 666                 hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 667                 au_sync();
 668         }
 669
 670         if (hw->rx_count >= hw->len) {
 671                 /* transfer completed successfully */
 672                 au1550_spi_mask_ack_all(hw);
 673                 complete(&hw->master_done);
 674         }
 675         return IRQ_HANDLED;
 676 }
 677
 678 static int au1550_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
 679 {
 680         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 681         return hw->txrx_bufs(spi, t);
 682 }
 683
 684 static irqreturn_t au1550_spi_irq(int irq, void *dev)
 685 {
 686         struct au1550_spi *hw = dev;
 687         return hw->irq_callback(hw);
 688 }
 689
 690 static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw)
 691 {
 692         if (bpw <= 8) {
 693                 if (hw->usedma) {
 694                         hw->txrx_bufs = &au1550_spi_dma_txrxb;
 695                         hw->irq_callback = &au1550_spi_dma_irq_callback;
 696                 } else {
 697                         hw->rx_word = &au1550_spi_rx_word_8;
 698                         hw->tx_word = &au1550_spi_tx_word_8;
 699                         hw->txrx_bufs = &au1550_spi_pio_txrxb;
 700                         hw->irq_callback = &au1550_spi_pio_irq_callback;
 701                 }
 702         } else if (bpw <= 16) {
 703                 hw->rx_word = &au1550_spi_rx_word_16;
 704                 hw->tx_word = &au1550_spi_tx_word_16;
 705                 hw->txrx_bufs = &au1550_spi_pio_txrxb;
 706                 hw->irq_callback = &au1550_spi_pio_irq_callback;
 707         } else {
 708                 hw->rx_word = &au1550_spi_rx_word_32;
 709                 hw->tx_word = &au1550_spi_tx_word_32;
 710                 hw->txrx_bufs = &au1550_spi_pio_txrxb;
 711                 hw->irq_callback = &au1550_spi_pio_irq_callback;
 712         }
 713 }
 714
 715 static void __init au1550_spi_setup_psc_as_spi(struct au1550_spi *hw)
 716 {
 717         u32 stat, cfg;
 718
 719         /* set up the PSC for SPI mode */
 720         hw->regs->psc_ctrl = PSC_CTRL_DISABLE;
 721         au_sync();
 722         hw->regs->psc_sel = PSC_SEL_PS_SPIMODE;
 723         au_sync();
 724
 725         hw->regs->psc_spicfg = 0;
 726         au_sync();
 727
 728         hw->regs->psc_ctrl = PSC_CTRL_ENABLE;
 729         au_sync();
 730
 731         do {
 732                 stat = hw->regs->psc_spistat;
 733                 au_sync();
 734         } while ((stat & PSC_SPISTAT_SR) == 0);
 735
 736
 737         cfg = hw->usedma ? 0 : PSC_SPICFG_DD_DISABLE;
 738         cfg |= PSC_SPICFG_SET_LEN(8);
 739         cfg |= PSC_SPICFG_RT_FIFO8 | PSC_SPICFG_TT_FIFO8;
 740         /* use minimal allowed brg and div values as initial setting: */
 741         cfg |= PSC_SPICFG_SET_BAUD(4) | PSC_SPICFG_SET_DIV(0);
 742
 743 #ifdef AU1550_SPI_DEBUG_LOOPBACK
 744         cfg |= PSC_SPICFG_LB;
 745 #endif
 746
 747         hw->regs->psc_spicfg = cfg;
 748         au_sync();
 749
 750         au1550_spi_mask_ack_all(hw);
 751
 752         hw->regs->psc_spicfg |= PSC_SPICFG_DE_ENABLE;
 753         au_sync();
 754
 755         do {
 756                 stat = hw->regs->psc_spistat;
 757                 au_sync();
 758         } while ((stat & PSC_SPISTAT_DR) == 0);
 759
 760         au1550_spi_reset_fifos(hw);
 761 }
 762
 763
 764 static int __init au1550_spi_probe(struct platform_device *pdev)
 765 {
 766         struct au1550_spi *hw;
 767         struct spi_master *master;
 768         struct resource *r;
 769         int err = 0;
 770
 771         master = spi_alloc_master(&pdev->dev, sizeof(struct au1550_spi));
 772         if (master == NULL) {
 773                 dev_err(&pdev->dev, "No memory for spi_master\n");
 774                 err = -ENOMEM;
 775                 goto err_nomem;
 776         }
 777
 778         hw = spi_master_get_devdata(master);
 779
 780         hw->master = spi_master_get(master);
 781         hw->pdata = pdev->dev.platform_data;
 782         hw->dev = &pdev->dev;
 783
 784         if (hw->pdata == NULL) {
 785                 dev_err(&pdev->dev, "No platform data supplied\n");
 786                 err = -ENOENT;
 787                 goto err_no_pdata;
 788         }
 789
 790         r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 791         if (!r) {
 792                 dev_err(&pdev->dev, "no IRQ\n");
 793                 err = -ENODEV;
 794                 goto err_no_iores;
 795         }
 796         hw->irq = r->start;
 797
 798         hw->usedma = 0;
 799         r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 800         if (r) {
 801                 hw->dma_tx_id = r->start;
 802                 r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
 803                 if (r) {
 804                         hw->dma_rx_id = r->start;
 805                         if (usedma && ddma_memid) {
 806                                 if (pdev->dev.dma_mask == NULL)
 807                                         dev_warn(&pdev->dev, "no dma mask\n");
 808                                 else
 809                                         hw->usedma = 1;
 810                         }
 811                 }
 812         }
 813
 814         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 815         if (!r) {
 816                 dev_err(&pdev->dev, "no mmio resource\n");
 817                 err = -ENODEV;
 818                 goto err_no_iores;
 819         }
 820
 821         hw->ioarea = request_mem_region(r->start, sizeof(psc_spi_t),
 822                                         pdev->name);
 823         if (!hw->ioarea) {
 824                 dev_err(&pdev->dev, "Cannot reserve iomem region\n");
 825                 err = -ENXIO;
 826                 goto err_no_iores;
 827         }
 828
 829         hw->regs = (psc_spi_t __iomem *)ioremap(r->start, sizeof(psc_spi_t));
 830         if (!hw->regs) {
 831                 dev_err(&pdev->dev, "cannot ioremap\n");
 832                 err = -ENXIO;
 833                 goto err_ioremap;
 834         }
 835
 836         platform_set_drvdata(pdev, hw);
 837
 838         init_completion(&hw->master_done);
 839
 840         hw->bitbang.master = hw->master;
 841         hw->bitbang.setup_transfer = au1550_spi_setupxfer;
 842         hw->bitbang.chipselect = au1550_spi_chipsel;
 843         hw->bitbang.master->setup = au1550_spi_setup;
 844         hw->bitbang.txrx_bufs = au1550_spi_txrx_bufs;
 845
 846         if (hw->usedma) {
 847                 hw->dma_tx_ch = au1xxx_dbdma_chan_alloc(ddma_memid,
 848                         hw->dma_tx_id, NULL, (void *)hw);
 849                 if (hw->dma_tx_ch == 0) {
 850                         dev_err(&pdev->dev,
 851                                 "Cannot allocate tx dma channel\n");
 852                         err = -ENXIO;
 853                         goto err_no_txdma;
 854                 }
 855                 au1xxx_dbdma_set_devwidth(hw->dma_tx_ch, 8);
 856                 if (au1xxx_dbdma_ring_alloc(hw->dma_tx_ch,
 857                         AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
 858                         dev_err(&pdev->dev,
 859                                 "Cannot allocate tx dma descriptors\n");
 860                         err = -ENXIO;
 861                         goto err_no_txdma_descr;
 862                 }
 863
 864
 865                 hw->dma_rx_ch = au1xxx_dbdma_chan_alloc(hw->dma_rx_id,
 866                         ddma_memid, NULL, (void *)hw);
 867                 if (hw->dma_rx_ch == 0) {
 868                         dev_err(&pdev->dev,
 869                                 "Cannot allocate rx dma channel\n");
 870                         err = -ENXIO;
 871                         goto err_no_rxdma;
 872                 }
 873                 au1xxx_dbdma_set_devwidth(hw->dma_rx_ch, 8);
 874                 if (au1xxx_dbdma_ring_alloc(hw->dma_rx_ch,
 875                         AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
 876                         dev_err(&pdev->dev,
 877                                 "Cannot allocate rx dma descriptors\n");
 878                         err = -ENXIO;
 879                         goto err_no_rxdma_descr;
 880                 }
 881
 882                 err = au1550_spi_dma_rxtmp_alloc(hw,
 883                         AU1550_SPI_DMA_RXTMP_MINSIZE);
 884                 if (err < 0) {
 885                         dev_err(&pdev->dev,
 886                                 "Cannot allocate initial rx dma tmp buffer\n");
 887                         goto err_dma_rxtmp_alloc;
 888                 }
 889         }
 890
 891         au1550_spi_bits_handlers_set(hw, 8);
 892
 893         err = request_irq(hw->irq, au1550_spi_irq, 0, pdev->name, hw);
 894         if (err) {
 895                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
 896                 goto err_no_irq;
 897         }
 898
 899         master->bus_num = pdev->id;
 900         master->num_chipselect = hw->pdata->num_chipselect;
 901
 902         /*
 903          *  precompute valid range for spi freq - from au1550 datasheet:
 904          *    psc_tempclk = psc_mainclk / (2 << DIV)
 905          *    spiclk = psc_tempclk / (2 * (BRG + 1))
 906          *    BRG valid range is 4..63
 907          *    DIV valid range is 0..3
 908          *  round the min and max frequencies to values that would still
 909          *  produce valid brg and div
 910          */
 911         {
 912                 int min_div = (2 << 0) * (2 * (4 + 1));
 913                 int max_div = (2 << 3) * (2 * (63 + 1));
 914                 hw->freq_max = hw->pdata->mainclk_hz / min_div;
 915                 hw->freq_min = hw->pdata->mainclk_hz / (max_div + 1) + 1;
 916         }
 917
 918         au1550_spi_setup_psc_as_spi(hw);
 919
 920         err = spi_bitbang_start(&hw->bitbang);
 921         if (err) {
 922                 dev_err(&pdev->dev, "Failed to register SPI master\n");
 923                 goto err_register;
 924         }
 925
 926         dev_info(&pdev->dev,
 927                 "spi master registered: bus_num=%d num_chipselect=%d\n",
 928                 master->bus_num, master->num_chipselect);
 929
 930         return 0;
 931
 932 err_register:
 933         free_irq(hw->irq, hw);
 934
 935 err_no_irq:
 936         au1550_spi_dma_rxtmp_free(hw);
 937
 938 err_dma_rxtmp_alloc:
 939 err_no_rxdma_descr:
 940         if (hw->usedma)
 941                 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
 942
 943 err_no_rxdma:
 944 err_no_txdma_descr:
 945         if (hw->usedma)
 946                 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
 947
 948 err_no_txdma:
 949         iounmap((void __iomem *)hw->regs);
 950
 951 err_ioremap:
 952         release_resource(hw->ioarea);
 953         kfree(hw->ioarea);
 954
 955 err_no_iores:
 956 err_no_pdata:
 957         spi_master_put(hw->master);
 958
 959 err_nomem:
 960         return err;
 961 }
 962
 963 static int __exit au1550_spi_remove(struct platform_device *pdev)
 964 {
 965         struct au1550_spi *hw = platform_get_drvdata(pdev);
 966
 967         dev_info(&pdev->dev, "spi master remove: bus_num=%d\n",
 968                 hw->master->bus_num);
 969
 970         spi_bitbang_stop(&hw->bitbang);
 971         free_irq(hw->irq, hw);
 972         iounmap((void __iomem *)hw->regs);
 973         release_resource(hw->ioarea);
 974         kfree(hw->ioarea);
 975
 976         if (hw->usedma) {
 977                 au1550_spi_dma_rxtmp_free(hw);
 978                 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
 979                 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
 980         }
 981
 982         platform_set_drvdata(pdev, NULL);
 983
 984         spi_master_put(hw->master);
 985         return 0;
 986 }
 987
 988 /* work with hotplug and coldplug */
 989 MODULE_ALIAS("platform:au1550-spi");
 990
 991 static struct platform_driver au1550_spi_drv = {
 992         .remove = __exit_p(au1550_spi_remove),
 993         .driver = {
 994                 .name = "au1550-spi",
 995                 .owner = THIS_MODULE,
 996         },
 997 };
 998
 999 static int __init au1550_spi_init(void)
1000 {
1001         /*
1002          * create memory device with 8 bits dev_devwidth
1003          * needed for proper byte ordering to spi fifo
1004          */
1005         if (usedma) {
1006                 ddma_memid = au1xxx_ddma_add_device(&au1550_spi_mem_dbdev);
1007                 if (!ddma_memid)
1008                         printk(KERN_ERR "au1550-spi: cannot add memory"
1009                                         "dbdma device\n");
1010         }
1011         return platform_driver_probe(&au1550_spi_drv, au1550_spi_probe);
1012 }
1013 module_init(au1550_spi_init);
1014
1015 static void __exit au1550_spi_exit(void)
1016 {
1017         if (usedma && ddma_memid)
1018                 au1xxx_ddma_del_device(ddma_memid);
1019         platform_driver_unregister(&au1550_spi_drv);
1020 }
1021 module_exit(au1550_spi_exit);
1022
1023 MODULE_DESCRIPTION("Au1550 PSC SPI Driver");
1024 MODULE_AUTHOR("Jan Nikitenko <jan.nikitenko@gmail.com>");
1025 MODULE_LICENSE("GPL");