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 = spi->bits_per_word;
 241         hz = spi->max_speed_hz;
 242         if (t) {
 243                 if (t->bits_per_word)
 244                         bpw = t->bits_per_word;
 245                 if (t->speed_hz)
 246                         hz = t->speed_hz;
 247         }
 248
 249         if (bpw < 4 || bpw > 24) {
 250                 dev_err(&spi->dev, "setupxfer: invalid bits_per_word=%d\n",
 251                         bpw);
 252                 return -EINVAL;
 253         }
 254         if (hz > spi->max_speed_hz || hz > hw->freq_max || hz < hw->freq_min) {
 255                 dev_err(&spi->dev, "setupxfer: clock rate=%d out of range\n",
 256                         hz);
 257                 return -EINVAL;
 258         }
 259
 260         au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
 261
 262         cfg = hw->regs->psc_spicfg;
 263         au_sync();
 264         hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
 265         au_sync();
 266
 267         if (hw->usedma && bpw <= 8)
 268                 cfg &= ~PSC_SPICFG_DD_DISABLE;
 269         else
 270                 cfg |= PSC_SPICFG_DD_DISABLE;
 271         cfg = PSC_SPICFG_CLR_LEN(cfg);
 272         cfg |= PSC_SPICFG_SET_LEN(bpw);
 273
 274         cfg = PSC_SPICFG_CLR_BAUD(cfg);
 275         cfg &= ~PSC_SPICFG_SET_DIV(3);
 276         cfg |= au1550_spi_baudcfg(hw, hz);
 277
 278         hw->regs->psc_spicfg = cfg;
 279         au_sync();
 280
 281         if (cfg & PSC_SPICFG_DE_ENABLE) {
 282                 do {
 283                         stat = hw->regs->psc_spistat;
 284                         au_sync();
 285                 } while ((stat & PSC_SPISTAT_DR) == 0);
 286         }
 287
 288         au1550_spi_reset_fifos(hw);
 289         au1550_spi_mask_ack_all(hw);
 290         return 0;
 291 }
 292
 293 static int au1550_spi_setup(struct spi_device *spi)
 294 {
 295         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 296
 297         if (spi->bits_per_word < 4 || spi->bits_per_word > 24) {
 298                 dev_err(&spi->dev, "setup: invalid bits_per_word=%d\n",
 299                         spi->bits_per_word);
 300                 return -EINVAL;
 301         }
 302
 303         if (spi->max_speed_hz == 0)
 304                 spi->max_speed_hz = hw->freq_max;
 305         if (spi->max_speed_hz > hw->freq_max
 306                         || spi->max_speed_hz < hw->freq_min)
 307                 return -EINVAL;
 308         /*
 309          * NOTE: cannot change speed and other hw settings immediately,
 310          *       otherwise sharing of spi bus is not possible,
 311          *       so do not call setupxfer(spi, NULL) here
 312          */
 313         return 0;
 314 }
 315
 316 /*
 317  * for dma spi transfers, we have to setup rx channel, otherwise there is
 318  * no reliable way how to recognize that spi transfer is done
 319  * dma complete callbacks are called before real spi transfer is finished
 320  * and if only tx dma channel is set up (and rx fifo overflow event masked)
 321  * spi master done event irq is not generated unless rx fifo is empty (emptied)
 322  * so we need rx tmp buffer to use for rx dma if user does not provide one
 323  */
 324 static int au1550_spi_dma_rxtmp_alloc(struct au1550_spi *hw, unsigned size)
 325 {
 326         hw->dma_rx_tmpbuf = kmalloc(size, GFP_KERNEL);
 327         if (!hw->dma_rx_tmpbuf)
 328                 return -ENOMEM;
 329         hw->dma_rx_tmpbuf_size = size;
 330         hw->dma_rx_tmpbuf_addr = dma_map_single(hw->dev, hw->dma_rx_tmpbuf,
 331                         size, DMA_FROM_DEVICE);
 332         if (dma_mapping_error(hw->dev, hw->dma_rx_tmpbuf_addr)) {
 333                 kfree(hw->dma_rx_tmpbuf);
 334                 hw->dma_rx_tmpbuf = 0;
 335                 hw->dma_rx_tmpbuf_size = 0;
 336                 return -EFAULT;
 337         }
 338         return 0;
 339 }
 340
 341 static void au1550_spi_dma_rxtmp_free(struct au1550_spi *hw)
 342 {
 343         dma_unmap_single(hw->dev, hw->dma_rx_tmpbuf_addr,
 344                         hw->dma_rx_tmpbuf_size, DMA_FROM_DEVICE);
 345         kfree(hw->dma_rx_tmpbuf);
 346         hw->dma_rx_tmpbuf = 0;
 347         hw->dma_rx_tmpbuf_size = 0;
 348 }
 349
 350 static int au1550_spi_dma_txrxb(struct spi_device *spi, struct spi_transfer *t)
 351 {
 352         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 353         dma_addr_t dma_tx_addr;
 354         dma_addr_t dma_rx_addr;
 355         u32 res;
 356
 357         hw->len = t->len;
 358         hw->tx_count = 0;
 359         hw->rx_count = 0;
 360
 361         hw->tx = t->tx_buf;
 362         hw->rx = t->rx_buf;
 363         dma_tx_addr = t->tx_dma;
 364         dma_rx_addr = t->rx_dma;
 365
 366         /*
 367          * check if buffers are already dma mapped, map them otherwise:
 368          * - first map the TX buffer, so cache data gets written to memory
 369          * - then map the RX buffer, so that cache entries (with
 370          *   soon-to-be-stale data) get removed
 371          * use rx buffer in place of tx if tx buffer was not provided
 372          * use temp rx buffer (preallocated or realloc to fit) for rx dma
 373          */
 374         if (t->tx_buf) {
 375                 if (t->tx_dma == 0) {   /* if DMA_ADDR_INVALID, map it */
 376                         dma_tx_addr = dma_map_single(hw->dev,
 377                                         (void *)t->tx_buf,
 378                                         t->len, DMA_TO_DEVICE);
 379                         if (dma_mapping_error(hw->dev, dma_tx_addr))
 380                                 dev_err(hw->dev, "tx dma map error\n");
 381                 }
 382         }
 383
 384         if (t->rx_buf) {
 385                 if (t->rx_dma == 0) {   /* if DMA_ADDR_INVALID, map it */
 386                         dma_rx_addr = dma_map_single(hw->dev,
 387                                         (void *)t->rx_buf,
 388                                         t->len, DMA_FROM_DEVICE);
 389                         if (dma_mapping_error(hw->dev, dma_rx_addr))
 390                                 dev_err(hw->dev, "rx dma map error\n");
 391                 }
 392         } else {
 393                 if (t->len > hw->dma_rx_tmpbuf_size) {
 394                         int ret;
 395
 396                         au1550_spi_dma_rxtmp_free(hw);
 397                         ret = au1550_spi_dma_rxtmp_alloc(hw, max(t->len,
 398                                         AU1550_SPI_DMA_RXTMP_MINSIZE));
 399                         if (ret < 0)
 400                                 return ret;
 401                 }
 402                 hw->rx = hw->dma_rx_tmpbuf;
 403                 dma_rx_addr = hw->dma_rx_tmpbuf_addr;
 404                 dma_sync_single_for_device(hw->dev, dma_rx_addr,
 405                         t->len, DMA_FROM_DEVICE);
 406         }
 407
 408         if (!t->tx_buf) {
 409                 dma_sync_single_for_device(hw->dev, dma_rx_addr,
 410                                 t->len, DMA_BIDIRECTIONAL);
 411                 hw->tx = hw->rx;
 412         }
 413
 414         /* put buffers on the ring */
 415         res = au1xxx_dbdma_put_dest(hw->dma_rx_ch, virt_to_phys(hw->rx),
 416                                     t->len, DDMA_FLAGS_IE);
 417         if (!res)
 418                 dev_err(hw->dev, "rx dma put dest error\n");
 419
 420         res = au1xxx_dbdma_put_source(hw->dma_tx_ch, virt_to_phys(hw->tx),
 421                                       t->len, DDMA_FLAGS_IE);
 422         if (!res)
 423                 dev_err(hw->dev, "tx dma put source error\n");
 424
 425         au1xxx_dbdma_start(hw->dma_rx_ch);
 426         au1xxx_dbdma_start(hw->dma_tx_ch);
 427
 428         /* by default enable nearly all events interrupt */
 429         hw->regs->psc_spimsk = PSC_SPIMSK_SD;
 430         au_sync();
 431
 432         /* start the transfer */
 433         hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 434         au_sync();
 435
 436         wait_for_completion(&hw->master_done);
 437
 438         au1xxx_dbdma_stop(hw->dma_tx_ch);
 439         au1xxx_dbdma_stop(hw->dma_rx_ch);
 440
 441         if (!t->rx_buf) {
 442                 /* using the temporal preallocated and premapped buffer */
 443                 dma_sync_single_for_cpu(hw->dev, dma_rx_addr, t->len,
 444                         DMA_FROM_DEVICE);
 445         }
 446         /* unmap buffers if mapped above */
 447         if (t->rx_buf && t->rx_dma == 0 )
 448                 dma_unmap_single(hw->dev, dma_rx_addr, t->len,
 449                         DMA_FROM_DEVICE);
 450         if (t->tx_buf && t->tx_dma == 0 )
 451                 dma_unmap_single(hw->dev, dma_tx_addr, t->len,
 452                         DMA_TO_DEVICE);
 453
 454         return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
 455 }
 456
 457 static irqreturn_t au1550_spi_dma_irq_callback(struct au1550_spi *hw)
 458 {
 459         u32 stat, evnt;
 460
 461         stat = hw->regs->psc_spistat;
 462         evnt = hw->regs->psc_spievent;
 463         au_sync();
 464         if ((stat & PSC_SPISTAT_DI) == 0) {
 465                 dev_err(hw->dev, "Unexpected IRQ!\n");
 466                 return IRQ_NONE;
 467         }
 468
 469         if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
 470                                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
 471                                 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD))
 472                         != 0) {
 473                 /*
 474                  * due to an spi error we consider transfer as done,
 475                  * so mask all events until before next transfer start
 476                  * and stop the possibly running dma immediatelly
 477                  */
 478                 au1550_spi_mask_ack_all(hw);
 479                 au1xxx_dbdma_stop(hw->dma_rx_ch);
 480                 au1xxx_dbdma_stop(hw->dma_tx_ch);
 481
 482                 /* get number of transfered bytes */
 483                 hw->rx_count = hw->len - au1xxx_get_dma_residue(hw->dma_rx_ch);
 484                 hw->tx_count = hw->len - au1xxx_get_dma_residue(hw->dma_tx_ch);
 485
 486                 au1xxx_dbdma_reset(hw->dma_rx_ch);
 487                 au1xxx_dbdma_reset(hw->dma_tx_ch);
 488                 au1550_spi_reset_fifos(hw);
 489
 490                 if (evnt == PSC_SPIEVNT_RO)
 491                         dev_err(hw->dev,
 492                                 "dma transfer: receive FIFO overflow!\n");
 493                 else
 494                         dev_err(hw->dev,
 495                                 "dma transfer: unexpected SPI error "
 496                                 "(event=0x%x stat=0x%x)!\n", evnt, stat);
 497
 498                 complete(&hw->master_done);
 499                 return IRQ_HANDLED;
 500         }
 501
 502         if ((evnt & PSC_SPIEVNT_MD) != 0) {
 503                 /* transfer completed successfully */
 504                 au1550_spi_mask_ack_all(hw);
 505                 hw->rx_count = hw->len;
 506                 hw->tx_count = hw->len;
 507                 complete(&hw->master_done);
 508         }
 509         return IRQ_HANDLED;
 510 }
 511
 512
 513 /* routines to handle different word sizes in pio mode */
 514 #define AU1550_SPI_RX_WORD(size, mask)                                  \
 515 static void au1550_spi_rx_word_##size(struct au1550_spi *hw)            \
 516 {                                                                       \
 517         u32 fifoword = hw->regs->psc_spitxrx & (u32)(mask);             \
 518         au_sync();                                                      \
 519         if (hw->rx) {                                                   \
 520                 *(u##size *)hw->rx = (u##size)fifoword;                 \
 521                 hw->rx += (size) / 8;                                   \
 522         }                                                               \
 523         hw->rx_count += (size) / 8;                                     \
 524 }
 525
 526 #define AU1550_SPI_TX_WORD(size, mask)                                  \
 527 static void au1550_spi_tx_word_##size(struct au1550_spi *hw)            \
 528 {                                                                       \
 529         u32 fifoword = 0;                                               \
 530         if (hw->tx) {                                                   \
 531                 fifoword = *(u##size *)hw->tx & (u32)(mask);            \
 532                 hw->tx += (size) / 8;                                   \
 533         }                                                               \
 534         hw->tx_count += (size) / 8;                                     \
 535         if (hw->tx_count >= hw->len)                                    \
 536                 fifoword |= PSC_SPITXRX_LC;                             \
 537         hw->regs->psc_spitxrx = fifoword;                               \
 538         au_sync();                                                      \
 539 }
 540
 541 AU1550_SPI_RX_WORD(8,0xff)
 542 AU1550_SPI_RX_WORD(16,0xffff)
 543 AU1550_SPI_RX_WORD(32,0xffffff)
 544 AU1550_SPI_TX_WORD(8,0xff)
 545 AU1550_SPI_TX_WORD(16,0xffff)
 546 AU1550_SPI_TX_WORD(32,0xffffff)
 547
 548 static int au1550_spi_pio_txrxb(struct spi_device *spi, struct spi_transfer *t)
 549 {
 550         u32 stat, mask;
 551         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 552
 553         hw->tx = t->tx_buf;
 554         hw->rx = t->rx_buf;
 555         hw->len = t->len;
 556         hw->tx_count = 0;
 557         hw->rx_count = 0;
 558
 559         /* by default enable nearly all events after filling tx fifo */
 560         mask = PSC_SPIMSK_SD;
 561
 562         /* fill the transmit FIFO */
 563         while (hw->tx_count < hw->len) {
 564
 565                 hw->tx_word(hw);
 566
 567                 if (hw->tx_count >= hw->len) {
 568                         /* mask tx fifo request interrupt as we are done */
 569                         mask |= PSC_SPIMSK_TR;
 570                 }
 571
 572                 stat = hw->regs->psc_spistat;
 573                 au_sync();
 574                 if (stat & PSC_SPISTAT_TF)
 575                         break;
 576         }
 577
 578         /* enable event interrupts */
 579         hw->regs->psc_spimsk = mask;
 580         au_sync();
 581
 582         /* start the transfer */
 583         hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 584         au_sync();
 585
 586         wait_for_completion(&hw->master_done);
 587
 588         return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
 589 }
 590
 591 static irqreturn_t au1550_spi_pio_irq_callback(struct au1550_spi *hw)
 592 {
 593         int busy;
 594         u32 stat, evnt;
 595
 596         stat = hw->regs->psc_spistat;
 597         evnt = hw->regs->psc_spievent;
 598         au_sync();
 599         if ((stat & PSC_SPISTAT_DI) == 0) {
 600                 dev_err(hw->dev, "Unexpected IRQ!\n");
 601                 return IRQ_NONE;
 602         }
 603
 604         if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
 605                                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
 606                                 | PSC_SPIEVNT_SD))
 607                         != 0) {
 608                 /*
 609                  * due to an error we consider transfer as done,
 610                  * so mask all events until before next transfer start
 611                  */
 612                 au1550_spi_mask_ack_all(hw);
 613                 au1550_spi_reset_fifos(hw);
 614                 dev_err(hw->dev,
 615                         "pio transfer: unexpected SPI error "
 616                         "(event=0x%x stat=0x%x)!\n", evnt, stat);
 617                 complete(&hw->master_done);
 618                 return IRQ_HANDLED;
 619         }
 620
 621         /*
 622          * while there is something to read from rx fifo
 623          * or there is a space to write to tx fifo:
 624          */
 625         do {
 626                 busy = 0;
 627                 stat = hw->regs->psc_spistat;
 628                 au_sync();
 629
 630                 /*
 631                  * Take care to not let the Rx FIFO overflow.
 632                  *
 633                  * We only write a byte if we have read one at least. Initially,
 634                  * the write fifo is full, so we should read from the read fifo
 635                  * first.
 636                  * In case we miss a word from the read fifo, we should get a
 637                  * RO event and should back out.
 638                  */
 639                 if (!(stat & PSC_SPISTAT_RE) && hw->rx_count < hw->len) {
 640                         hw->rx_word(hw);
 641                         busy = 1;
 642
 643                         if (!(stat & PSC_SPISTAT_TF) && hw->tx_count < hw->len)
 644                                 hw->tx_word(hw);
 645                 }
 646         } while (busy);
 647
 648         hw->regs->psc_spievent = PSC_SPIEVNT_RR | PSC_SPIEVNT_TR;
 649         au_sync();
 650
 651         /*
 652          * Restart the SPI transmission in case of a transmit underflow.
 653          * This seems to work despite the notes in the Au1550 data book
 654          * of Figure 8-4 with flowchart for SPI master operation:
 655          *
 656          * """Note 1: An XFR Error Interrupt occurs, unless masked,
 657          * for any of the following events: Tx FIFO Underflow,
 658          * Rx FIFO Overflow, or Multiple-master Error
 659          *    Note 2: In case of a Tx Underflow Error, all zeroes are
 660          * transmitted."""
 661          *
 662          * By simply restarting the spi transfer on Tx Underflow Error,
 663          * we assume that spi transfer was paused instead of zeroes
 664          * transmittion mentioned in the Note 2 of Au1550 data book.
 665          */
 666         if (evnt & PSC_SPIEVNT_TU) {
 667                 hw->regs->psc_spievent = PSC_SPIEVNT_TU | PSC_SPIEVNT_MD;
 668                 au_sync();
 669                 hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 670                 au_sync();
 671         }
 672
 673         if (hw->rx_count >= hw->len) {
 674                 /* transfer completed successfully */
 675                 au1550_spi_mask_ack_all(hw);
 676                 complete(&hw->master_done);
 677         }
 678         return IRQ_HANDLED;
 679 }
 680
 681 static int au1550_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
 682 {
 683         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 684         return hw->txrx_bufs(spi, t);
 685 }
 686
 687 static irqreturn_t au1550_spi_irq(int irq, void *dev)
 688 {
 689         struct au1550_spi *hw = dev;
 690         return hw->irq_callback(hw);
 691 }
 692
 693 static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw)
 694 {
 695         if (bpw <= 8) {
 696                 if (hw->usedma) {
 697                         hw->txrx_bufs = &au1550_spi_dma_txrxb;
 698                         hw->irq_callback = &au1550_spi_dma_irq_callback;
 699                 } else {
 700                         hw->rx_word = &au1550_spi_rx_word_8;
 701                         hw->tx_word = &au1550_spi_tx_word_8;
 702                         hw->txrx_bufs = &au1550_spi_pio_txrxb;
 703                         hw->irq_callback = &au1550_spi_pio_irq_callback;
 704                 }
 705         } else if (bpw <= 16) {
 706                 hw->rx_word = &au1550_spi_rx_word_16;
 707                 hw->tx_word = &au1550_spi_tx_word_16;
 708                 hw->txrx_bufs = &au1550_spi_pio_txrxb;
 709                 hw->irq_callback = &au1550_spi_pio_irq_callback;
 710         } else {
 711                 hw->rx_word = &au1550_spi_rx_word_32;
 712                 hw->tx_word = &au1550_spi_tx_word_32;
 713                 hw->txrx_bufs = &au1550_spi_pio_txrxb;
 714                 hw->irq_callback = &au1550_spi_pio_irq_callback;
 715         }
 716 }
 717
 718 static void __init au1550_spi_setup_psc_as_spi(struct au1550_spi *hw)
 719 {
 720         u32 stat, cfg;
 721
 722         /* set up the PSC for SPI mode */
 723         hw->regs->psc_ctrl = PSC_CTRL_DISABLE;
 724         au_sync();
 725         hw->regs->psc_sel = PSC_SEL_PS_SPIMODE;
 726         au_sync();
 727
 728         hw->regs->psc_spicfg = 0;
 729         au_sync();
 730
 731         hw->regs->psc_ctrl = PSC_CTRL_ENABLE;
 732         au_sync();
 733
 734         do {
 735                 stat = hw->regs->psc_spistat;
 736                 au_sync();
 737         } while ((stat & PSC_SPISTAT_SR) == 0);
 738
 739
 740         cfg = hw->usedma ? 0 : PSC_SPICFG_DD_DISABLE;
 741         cfg |= PSC_SPICFG_SET_LEN(8);
 742         cfg |= PSC_SPICFG_RT_FIFO8 | PSC_SPICFG_TT_FIFO8;
 743         /* use minimal allowed brg and div values as initial setting: */
 744         cfg |= PSC_SPICFG_SET_BAUD(4) | PSC_SPICFG_SET_DIV(0);
 745
 746 #ifdef AU1550_SPI_DEBUG_LOOPBACK
 747         cfg |= PSC_SPICFG_LB;
 748 #endif
 749
 750         hw->regs->psc_spicfg = cfg;
 751         au_sync();
 752
 753         au1550_spi_mask_ack_all(hw);
 754
 755         hw->regs->psc_spicfg |= PSC_SPICFG_DE_ENABLE;
 756         au_sync();
 757
 758         do {
 759                 stat = hw->regs->psc_spistat;
 760                 au_sync();
 761         } while ((stat & PSC_SPISTAT_DR) == 0);
 762
 763         au1550_spi_reset_fifos(hw);
 764 }
 765
 766
 767 static int __init au1550_spi_probe(struct platform_device *pdev)
 768 {
 769         struct au1550_spi *hw;
 770         struct spi_master *master;
 771         struct resource *r;
 772         int err = 0;
 773
 774         master = spi_alloc_master(&pdev->dev, sizeof(struct au1550_spi));
 775         if (master == NULL) {
 776                 dev_err(&pdev->dev, "No memory for spi_master\n");
 777                 err = -ENOMEM;
 778                 goto err_nomem;
 779         }
 780
 781         /* the spi->mode bits understood by this driver: */
 782         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
 783
 784         hw = spi_master_get_devdata(master);
 785
 786         hw->master = spi_master_get(master);
 787         hw->pdata = pdev->dev.platform_data;
 788         hw->dev = &pdev->dev;
 789
 790         if (hw->pdata == NULL) {
 791                 dev_err(&pdev->dev, "No platform data supplied\n");
 792                 err = -ENOENT;
 793                 goto err_no_pdata;
 794         }
 795
 796         r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 797         if (!r) {
 798                 dev_err(&pdev->dev, "no IRQ\n");
 799                 err = -ENODEV;
 800                 goto err_no_iores;
 801         }
 802         hw->irq = r->start;
 803
 804         hw->usedma = 0;
 805         r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 806         if (r) {
 807                 hw->dma_tx_id = r->start;
 808                 r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
 809                 if (r) {
 810                         hw->dma_rx_id = r->start;
 811                         if (usedma && ddma_memid) {
 812                                 if (pdev->dev.dma_mask == NULL)
 813                                         dev_warn(&pdev->dev, "no dma mask\n");
 814                                 else
 815                                         hw->usedma = 1;
 816                         }
 817                 }
 818         }
 819
 820         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 821         if (!r) {
 822                 dev_err(&pdev->dev, "no mmio resource\n");
 823                 err = -ENODEV;
 824                 goto err_no_iores;
 825         }
 826
 827         hw->ioarea = request_mem_region(r->start, sizeof(psc_spi_t),
 828                                         pdev->name);
 829         if (!hw->ioarea) {
 830                 dev_err(&pdev->dev, "Cannot reserve iomem region\n");
 831                 err = -ENXIO;
 832                 goto err_no_iores;
 833         }
 834
 835         hw->regs = (psc_spi_t __iomem *)ioremap(r->start, sizeof(psc_spi_t));
 836         if (!hw->regs) {
 837                 dev_err(&pdev->dev, "cannot ioremap\n");
 838                 err = -ENXIO;
 839                 goto err_ioremap;
 840         }
 841
 842         platform_set_drvdata(pdev, hw);
 843
 844         init_completion(&hw->master_done);
 845
 846         hw->bitbang.master = hw->master;
 847         hw->bitbang.setup_transfer = au1550_spi_setupxfer;
 848         hw->bitbang.chipselect = au1550_spi_chipsel;
 849         hw->bitbang.master->setup = au1550_spi_setup;
 850         hw->bitbang.txrx_bufs = au1550_spi_txrx_bufs;
 851
 852         if (hw->usedma) {
 853                 hw->dma_tx_ch = au1xxx_dbdma_chan_alloc(ddma_memid,
 854                         hw->dma_tx_id, NULL, (void *)hw);
 855                 if (hw->dma_tx_ch == 0) {
 856                         dev_err(&pdev->dev,
 857                                 "Cannot allocate tx dma channel\n");
 858                         err = -ENXIO;
 859                         goto err_no_txdma;
 860                 }
 861                 au1xxx_dbdma_set_devwidth(hw->dma_tx_ch, 8);
 862                 if (au1xxx_dbdma_ring_alloc(hw->dma_tx_ch,
 863                         AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
 864                         dev_err(&pdev->dev,
 865                                 "Cannot allocate tx dma descriptors\n");
 866                         err = -ENXIO;
 867                         goto err_no_txdma_descr;
 868                 }
 869
 870
 871                 hw->dma_rx_ch = au1xxx_dbdma_chan_alloc(hw->dma_rx_id,
 872                         ddma_memid, NULL, (void *)hw);
 873                 if (hw->dma_rx_ch == 0) {
 874                         dev_err(&pdev->dev,
 875                                 "Cannot allocate rx dma channel\n");
 876                         err = -ENXIO;
 877                         goto err_no_rxdma;
 878                 }
 879                 au1xxx_dbdma_set_devwidth(hw->dma_rx_ch, 8);
 880                 if (au1xxx_dbdma_ring_alloc(hw->dma_rx_ch,
 881                         AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
 882                         dev_err(&pdev->dev,
 883                                 "Cannot allocate rx dma descriptors\n");
 884                         err = -ENXIO;
 885                         goto err_no_rxdma_descr;
 886                 }
 887
 888                 err = au1550_spi_dma_rxtmp_alloc(hw,
 889                         AU1550_SPI_DMA_RXTMP_MINSIZE);
 890                 if (err < 0) {
 891                         dev_err(&pdev->dev,
 892                                 "Cannot allocate initial rx dma tmp buffer\n");
 893                         goto err_dma_rxtmp_alloc;
 894                 }
 895         }
 896
 897         au1550_spi_bits_handlers_set(hw, 8);
 898
 899         err = request_irq(hw->irq, au1550_spi_irq, 0, pdev->name, hw);
 900         if (err) {
 901                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
 902                 goto err_no_irq;
 903         }
 904
 905         master->bus_num = pdev->id;
 906         master->num_chipselect = hw->pdata->num_chipselect;
 907
 908         /*
 909          *  precompute valid range for spi freq - from au1550 datasheet:
 910          *    psc_tempclk = psc_mainclk / (2 << DIV)
 911          *    spiclk = psc_tempclk / (2 * (BRG + 1))
 912          *    BRG valid range is 4..63
 913          *    DIV valid range is 0..3
 914          *  round the min and max frequencies to values that would still
 915          *  produce valid brg and div
 916          */
 917         {
 918                 int min_div = (2 << 0) * (2 * (4 + 1));
 919                 int max_div = (2 << 3) * (2 * (63 + 1));
 920                 hw->freq_max = hw->pdata->mainclk_hz / min_div;
 921                 hw->freq_min = hw->pdata->mainclk_hz / (max_div + 1) + 1;
 922         }
 923
 924         au1550_spi_setup_psc_as_spi(hw);
 925
 926         err = spi_bitbang_start(&hw->bitbang);
 927         if (err) {
 928                 dev_err(&pdev->dev, "Failed to register SPI master\n");
 929                 goto err_register;
 930         }
 931
 932         dev_info(&pdev->dev,
 933                 "spi master registered: bus_num=%d num_chipselect=%d\n",
 934                 master->bus_num, master->num_chipselect);
 935
 936         return 0;
 937
 938 err_register:
 939         free_irq(hw->irq, hw);
 940
 941 err_no_irq:
 942         au1550_spi_dma_rxtmp_free(hw);
 943
 944 err_dma_rxtmp_alloc:
 945 err_no_rxdma_descr:
 946         if (hw->usedma)
 947                 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
 948
 949 err_no_rxdma:
 950 err_no_txdma_descr:
 951         if (hw->usedma)
 952                 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
 953
 954 err_no_txdma:
 955         iounmap((void __iomem *)hw->regs);
 956
 957 err_ioremap:
 958         release_resource(hw->ioarea);
 959         kfree(hw->ioarea);
 960
 961 err_no_iores:
 962 err_no_pdata:
 963         spi_master_put(hw->master);
 964
 965 err_nomem:
 966         return err;
 967 }
 968
 969 static int __exit au1550_spi_remove(struct platform_device *pdev)
 970 {
 971         struct au1550_spi *hw = platform_get_drvdata(pdev);
 972
 973         dev_info(&pdev->dev, "spi master remove: bus_num=%d\n",
 974                 hw->master->bus_num);
 975
 976         spi_bitbang_stop(&hw->bitbang);
 977         free_irq(hw->irq, hw);
 978         iounmap((void __iomem *)hw->regs);
 979         release_resource(hw->ioarea);
 980         kfree(hw->ioarea);
 981
 982         if (hw->usedma) {
 983                 au1550_spi_dma_rxtmp_free(hw);
 984                 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
 985                 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
 986         }
 987
 988         platform_set_drvdata(pdev, NULL);
 989
 990         spi_master_put(hw->master);
 991         return 0;
 992 }
 993
 994 /* work with hotplug and coldplug */
 995 MODULE_ALIAS("platform:au1550-spi");
 996
 997 static struct platform_driver au1550_spi_drv = {
 998         .remove = __exit_p(au1550_spi_remove),
 999         .driver = {
1000                 .name = "au1550-spi",
1001                 .owner = THIS_MODULE,
1002         },
1003 };
1004
1005 static int __init au1550_spi_init(void)
1006 {
1007         /*
1008          * create memory device with 8 bits dev_devwidth
1009          * needed for proper byte ordering to spi fifo
1010          */
1011         if (usedma) {
1012                 ddma_memid = au1xxx_ddma_add_device(&au1550_spi_mem_dbdev);
1013                 if (!ddma_memid)
1014                         printk(KERN_ERR "au1550-spi: cannot add memory"
1015                                         "dbdma device\n");
1016         }
1017         return platform_driver_probe(&au1550_spi_drv, au1550_spi_probe);
1018 }
1019 module_init(au1550_spi_init);
1020
1021 static void __exit au1550_spi_exit(void)
1022 {
1023         if (usedma && ddma_memid)
1024                 au1xxx_ddma_del_device(ddma_memid);
1025         platform_driver_unregister(&au1550_spi_drv);
1026 }
1027 module_exit(au1550_spi_exit);
1028
1029 MODULE_DESCRIPTION("Au1550 PSC SPI Driver");
1030 MODULE_AUTHOR("Jan Nikitenko <jan.nikitenko@gmail.com>");
1031 MODULE_LICENSE("GPL");