git.oblomov.eu Git - linux-2.6/blob - 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/spi/spi.h>
  30 #include <linux/spi/spi_bitbang.h>
  31 #include <linux/dma-mapping.h>
  32 #include <linux/completion.h>
  33 #include <asm/mach-au1x00/au1000.h>
  34 #include <asm/mach-au1x00/au1xxx_psc.h>
  35 #include <asm/mach-au1x00/au1xxx_dbdma.h>
  36
  37 #include <asm/mach-au1x00/au1550_spi.h>
  38
  39 static unsigned usedma = 1;
  40 module_param(usedma, uint, 0644);
  41
  42 /*
  43 #define AU1550_SPI_DEBUG_LOOPBACK
  44 */
  45
  46
  47 #define AU1550_SPI_DBDMA_DESCRIPTORS 1
  48 #define AU1550_SPI_DMA_RXTMP_MINSIZE 2048U
  49
  50 struct au1550_spi {
  51         struct spi_bitbang bitbang;
  52
  53         volatile psc_spi_t __iomem *regs;
  54         int irq;
  55         unsigned freq_max;
  56         unsigned freq_min;
  57
  58         unsigned len;
  59         unsigned tx_count;
  60         unsigned rx_count;
  61         const u8 *tx;
  62         u8 *rx;
  63
  64         void (*rx_word)(struct au1550_spi *hw);
  65         void (*tx_word)(struct au1550_spi *hw);
  66         int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
  67         irqreturn_t (*irq_callback)(struct au1550_spi *hw);
  68
  69         struct completion master_done;
  70
  71         unsigned usedma;
  72         u32 dma_tx_id;
  73         u32 dma_rx_id;
  74         u32 dma_tx_ch;
  75         u32 dma_rx_ch;
  76
  77         u8 *dma_rx_tmpbuf;
  78         unsigned dma_rx_tmpbuf_size;
  79         u32 dma_rx_tmpbuf_addr;
  80
  81         struct spi_master *master;
  82         struct device *dev;
  83         struct au1550_spi_info *pdata;
  84 };
  85
  86
  87 /* we use an 8-bit memory device for dma transfers to/from spi fifo */
  88 static dbdev_tab_t au1550_spi_mem_dbdev =
  89 {
  90         .dev_id                 = DBDMA_MEM_CHAN,
  91         .dev_flags              = DEV_FLAGS_ANYUSE|DEV_FLAGS_SYNC,
  92         .dev_tsize              = 0,
  93         .dev_devwidth           = 8,
  94         .dev_physaddr           = 0x00000000,
  95         .dev_intlevel           = 0,
  96         .dev_intpolarity        = 0
  97 };
  98
  99 static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw);
 100
 101
 102 /*
 103  *  compute BRG and DIV bits to setup spi clock based on main input clock rate
 104  *  that was specified in platform data structure
 105  *  according to au1550 datasheet:
 106  *    psc_tempclk = psc_mainclk / (2 << DIV)
 107  *    spiclk = psc_tempclk / (2 * (BRG + 1))
 108  *    BRG valid range is 4..63
 109  *    DIV valid range is 0..3
 110  */
 111 static u32 au1550_spi_baudcfg(struct au1550_spi *hw, unsigned speed_hz)
 112 {
 113         u32 mainclk_hz = hw->pdata->mainclk_hz;
 114         u32 div, brg;
 115
 116         for (div = 0; div < 4; div++) {
 117                 brg = mainclk_hz / speed_hz / (4 << div);
 118                 /* now we have BRG+1 in brg, so count with that */
 119                 if (brg < (4 + 1)) {
 120                         brg = (4 + 1);  /* speed_hz too big */
 121                         break;          /* set lowest brg (div is == 0) */
 122                 }
 123                 if (brg <= (63 + 1))
 124                         break;          /* we have valid brg and div */
 125         }
 126         if (div == 4) {
 127                 div = 3;                /* speed_hz too small */
 128                 brg = (63 + 1);         /* set highest brg and div */
 129         }
 130         brg--;
 131         return PSC_SPICFG_SET_BAUD(brg) | PSC_SPICFG_SET_DIV(div);
 132 }
 133
 134 static inline void au1550_spi_mask_ack_all(struct au1550_spi *hw)
 135 {
 136         hw->regs->psc_spimsk =
 137                   PSC_SPIMSK_MM | PSC_SPIMSK_RR | PSC_SPIMSK_RO
 138                 | PSC_SPIMSK_RU | PSC_SPIMSK_TR | PSC_SPIMSK_TO
 139                 | PSC_SPIMSK_TU | PSC_SPIMSK_SD | PSC_SPIMSK_MD;
 140         au_sync();
 141
 142         hw->regs->psc_spievent =
 143                   PSC_SPIEVNT_MM | PSC_SPIEVNT_RR | PSC_SPIEVNT_RO
 144                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TR | PSC_SPIEVNT_TO
 145                 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD | PSC_SPIEVNT_MD;
 146         au_sync();
 147 }
 148
 149 static void au1550_spi_reset_fifos(struct au1550_spi *hw)
 150 {
 151         u32 pcr;
 152
 153         hw->regs->psc_spipcr = PSC_SPIPCR_RC | PSC_SPIPCR_TC;
 154         au_sync();
 155         do {
 156                 pcr = hw->regs->psc_spipcr;
 157                 au_sync();
 158         } while (pcr != 0);
 159 }
 160
 161 /*
 162  * dma transfers are used for the most common spi word size of 8-bits
 163  * we cannot easily change already set up dma channels' width, so if we wanted
 164  * dma support for more than 8-bit words (up to 24 bits), we would need to
 165  * setup dma channels from scratch on each spi transfer, based on bits_per_word
 166  * instead we have pre set up 8 bit dma channels supporting spi 4 to 8 bits
 167  * transfers, and 9 to 24 bits spi transfers will be done in pio irq based mode
 168  * callbacks to handle dma or pio are set up in au1550_spi_bits_handlers_set()
 169  */
 170 static void au1550_spi_chipsel(struct spi_device *spi, int value)
 171 {
 172         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 173         unsigned cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
 174         u32 cfg, stat;
 175
 176         switch (value) {
 177         case BITBANG_CS_INACTIVE:
 178                 if (hw->pdata->deactivate_cs)
 179                         hw->pdata->deactivate_cs(hw->pdata, spi->chip_select,
 180                                         cspol);
 181                 break;
 182
 183         case BITBANG_CS_ACTIVE:
 184                 au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
 185
 186                 cfg = hw->regs->psc_spicfg;
 187                 au_sync();
 188                 hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
 189                 au_sync();
 190
 191                 if (spi->mode & SPI_CPOL)
 192                         cfg |= PSC_SPICFG_BI;
 193                 else
 194                         cfg &= ~PSC_SPICFG_BI;
 195                 if (spi->mode & SPI_CPHA)
 196                         cfg &= ~PSC_SPICFG_CDE;
 197                 else
 198                         cfg |= PSC_SPICFG_CDE;
 199
 200                 if (spi->mode & SPI_LSB_FIRST)
 201                         cfg |= PSC_SPICFG_MLF;
 202                 else
 203                         cfg &= ~PSC_SPICFG_MLF;
 204
 205                 if (hw->usedma && spi->bits_per_word <= 8)
 206                         cfg &= ~PSC_SPICFG_DD_DISABLE;
 207                 else
 208                         cfg |= PSC_SPICFG_DD_DISABLE;
 209                 cfg = PSC_SPICFG_CLR_LEN(cfg);
 210                 cfg |= PSC_SPICFG_SET_LEN(spi->bits_per_word);
 211
 212                 cfg = PSC_SPICFG_CLR_BAUD(cfg);
 213                 cfg &= ~PSC_SPICFG_SET_DIV(3);
 214                 cfg |= au1550_spi_baudcfg(hw, spi->max_speed_hz);
 215
 216                 hw->regs->psc_spicfg = cfg | PSC_SPICFG_DE_ENABLE;
 217                 au_sync();
 218                 do {
 219                         stat = hw->regs->psc_spistat;
 220                         au_sync();
 221                 } while ((stat & PSC_SPISTAT_DR) == 0);
 222
 223                 if (hw->pdata->activate_cs)
 224                         hw->pdata->activate_cs(hw->pdata, spi->chip_select,
 225                                         cspol);
 226                 break;
 227         }
 228 }
 229
 230 static int au1550_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
 231 {
 232         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 233         unsigned bpw, hz;
 234         u32 cfg, stat;
 235
 236         bpw = t ? t->bits_per_word : spi->bits_per_word;
 237         hz = t ? t->speed_hz : spi->max_speed_hz;
 238
 239         if (bpw < 4 || bpw > 24) {
 240                 dev_err(&spi->dev, "setupxfer: invalid bits_per_word=%d\n",
 241                         bpw);
 242                 return -EINVAL;
 243         }
 244         if (hz > spi->max_speed_hz || hz > hw->freq_max || hz < hw->freq_min) {
 245                 dev_err(&spi->dev, "setupxfer: clock rate=%d out of range\n",
 246                         hz);
 247                 return -EINVAL;
 248         }
 249
 250         au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
 251
 252         cfg = hw->regs->psc_spicfg;
 253         au_sync();
 254         hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
 255         au_sync();
 256
 257         if (hw->usedma && bpw <= 8)
 258                 cfg &= ~PSC_SPICFG_DD_DISABLE;
 259         else
 260                 cfg |= PSC_SPICFG_DD_DISABLE;
 261         cfg = PSC_SPICFG_CLR_LEN(cfg);
 262         cfg |= PSC_SPICFG_SET_LEN(bpw);
 263
 264         cfg = PSC_SPICFG_CLR_BAUD(cfg);
 265         cfg &= ~PSC_SPICFG_SET_DIV(3);
 266         cfg |= au1550_spi_baudcfg(hw, hz);
 267
 268         hw->regs->psc_spicfg = cfg;
 269         au_sync();
 270
 271         if (cfg & PSC_SPICFG_DE_ENABLE) {
 272                 do {
 273                         stat = hw->regs->psc_spistat;
 274                         au_sync();
 275                 } while ((stat & PSC_SPISTAT_DR) == 0);
 276         }
 277
 278         au1550_spi_reset_fifos(hw);
 279         au1550_spi_mask_ack_all(hw);
 280         return 0;
 281 }
 282
 283 /* the spi->mode bits understood by this driver: */
 284 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST)
 285
 286 static int au1550_spi_setup(struct spi_device *spi)
 287 {
 288         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 289
 290         if (spi->bits_per_word == 0)
 291                 spi->bits_per_word = 8;
 292         if (spi->bits_per_word < 4 || spi->bits_per_word > 24) {
 293                 dev_err(&spi->dev, "setup: invalid bits_per_word=%d\n",
 294                         spi->bits_per_word);
 295                 return -EINVAL;
 296         }
 297
 298         if (spi->mode & ~MODEBITS) {
 299                 dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
 300                         spi->mode & ~MODEBITS);
 301                 return -EINVAL;
 302         }
 303
 304         if (spi->max_speed_hz == 0)
 305                 spi->max_speed_hz = hw->freq_max;
 306         if (spi->max_speed_hz > hw->freq_max
 307                         || spi->max_speed_hz < hw->freq_min)
 308                 return -EINVAL;
 309         /*
 310          * NOTE: cannot change speed and other hw settings immediately,
 311          *       otherwise sharing of spi bus is not possible,
 312          *       so do not call setupxfer(spi, NULL) here
 313          */
 314         return 0;
 315 }
 316
 317 /*
 318  * for dma spi transfers, we have to setup rx channel, otherwise there is
 319  * no reliable way how to recognize that spi transfer is done
 320  * dma complete callbacks are called before real spi transfer is finished
 321  * and if only tx dma channel is set up (and rx fifo overflow event masked)
 322  * spi master done event irq is not generated unless rx fifo is empty (emptied)
 323  * so we need rx tmp buffer to use for rx dma if user does not provide one
 324  */
 325 static int au1550_spi_dma_rxtmp_alloc(struct au1550_spi *hw, unsigned size)
 326 {
 327         hw->dma_rx_tmpbuf = kmalloc(size, GFP_KERNEL);
 328         if (!hw->dma_rx_tmpbuf)
 329                 return -ENOMEM;
 330         hw->dma_rx_tmpbuf_size = size;
 331         hw->dma_rx_tmpbuf_addr = dma_map_single(hw->dev, hw->dma_rx_tmpbuf,
 332                         size, DMA_FROM_DEVICE);
 333         if (dma_mapping_error(hw->dma_rx_tmpbuf_addr)) {
 334                 kfree(hw->dma_rx_tmpbuf);
 335                 hw->dma_rx_tmpbuf = 0;
 336                 hw->dma_rx_tmpbuf_size = 0;
 337                 return -EFAULT;
 338         }
 339         return 0;
 340 }
 341
 342 static void au1550_spi_dma_rxtmp_free(struct au1550_spi *hw)
 343 {
 344         dma_unmap_single(hw->dev, hw->dma_rx_tmpbuf_addr,
 345                         hw->dma_rx_tmpbuf_size, DMA_FROM_DEVICE);
 346         kfree(hw->dma_rx_tmpbuf);
 347         hw->dma_rx_tmpbuf = 0;
 348         hw->dma_rx_tmpbuf_size = 0;
 349 }
 350
 351 static int au1550_spi_dma_txrxb(struct spi_device *spi, struct spi_transfer *t)
 352 {
 353         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 354         dma_addr_t dma_tx_addr;
 355         dma_addr_t dma_rx_addr;
 356         u32 res;
 357
 358         hw->len = t->len;
 359         hw->tx_count = 0;
 360         hw->rx_count = 0;
 361
 362         hw->tx = t->tx_buf;
 363         hw->rx = t->rx_buf;
 364         dma_tx_addr = t->tx_dma;
 365         dma_rx_addr = t->rx_dma;
 366
 367         /*
 368          * check if buffers are already dma mapped, map them otherwise
 369          * use rx buffer in place of tx if tx buffer was not provided
 370          * use temp rx buffer (preallocated or realloc to fit) for rx dma
 371          */
 372         if (t->rx_buf) {
 373                 if (t->rx_dma == 0) {   /* if DMA_ADDR_INVALID, map it */
 374                         dma_rx_addr = dma_map_single(hw->dev,
 375                                         (void *)t->rx_buf,
 376                                         t->len, DMA_FROM_DEVICE);
 377                         if (dma_mapping_error(dma_rx_addr))
 378                                 dev_err(hw->dev, "rx dma map error\n");
 379                 }
 380         } else {
 381                 if (t->len > hw->dma_rx_tmpbuf_size) {
 382                         int ret;
 383
 384                         au1550_spi_dma_rxtmp_free(hw);
 385                         ret = au1550_spi_dma_rxtmp_alloc(hw, max(t->len,
 386                                         AU1550_SPI_DMA_RXTMP_MINSIZE));
 387                         if (ret < 0)
 388                                 return ret;
 389                 }
 390                 hw->rx = hw->dma_rx_tmpbuf;
 391                 dma_rx_addr = hw->dma_rx_tmpbuf_addr;
 392                 dma_sync_single_for_device(hw->dev, dma_rx_addr,
 393                         t->len, DMA_FROM_DEVICE);
 394         }
 395         if (t->tx_buf) {
 396                 if (t->tx_dma == 0) {   /* if DMA_ADDR_INVALID, map it */
 397                         dma_tx_addr = dma_map_single(hw->dev,
 398                                         (void *)t->tx_buf,
 399                                         t->len, DMA_TO_DEVICE);
 400                         if (dma_mapping_error(dma_tx_addr))
 401                                 dev_err(hw->dev, "tx dma map error\n");
 402                 }
 403         } else {
 404                 dma_sync_single_for_device(hw->dev, dma_rx_addr,
 405                                 t->len, DMA_BIDIRECTIONAL);
 406                 hw->tx = hw->rx;
 407         }
 408
 409         /* put buffers on the ring */
 410         res = au1xxx_dbdma_put_dest(hw->dma_rx_ch, hw->rx, t->len);
 411         if (!res)
 412                 dev_err(hw->dev, "rx dma put dest error\n");
 413
 414         res = au1xxx_dbdma_put_source(hw->dma_tx_ch, (void *)hw->tx, t->len);
 415         if (!res)
 416                 dev_err(hw->dev, "tx dma put source error\n");
 417
 418         au1xxx_dbdma_start(hw->dma_rx_ch);
 419         au1xxx_dbdma_start(hw->dma_tx_ch);
 420
 421         /* by default enable nearly all events interrupt */
 422         hw->regs->psc_spimsk = PSC_SPIMSK_SD;
 423         au_sync();
 424
 425         /* start the transfer */
 426         hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 427         au_sync();
 428
 429         wait_for_completion(&hw->master_done);
 430
 431         au1xxx_dbdma_stop(hw->dma_tx_ch);
 432         au1xxx_dbdma_stop(hw->dma_rx_ch);
 433
 434         if (!t->rx_buf) {
 435                 /* using the temporal preallocated and premapped buffer */
 436                 dma_sync_single_for_cpu(hw->dev, dma_rx_addr, t->len,
 437                         DMA_FROM_DEVICE);
 438         }
 439         /* unmap buffers if mapped above */
 440         if (t->rx_buf && t->rx_dma == 0 )
 441                 dma_unmap_single(hw->dev, dma_rx_addr, t->len,
 442                         DMA_FROM_DEVICE);
 443         if (t->tx_buf && t->tx_dma == 0 )
 444                 dma_unmap_single(hw->dev, dma_tx_addr, t->len,
 445                         DMA_TO_DEVICE);
 446
 447         return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
 448 }
 449
 450 static irqreturn_t au1550_spi_dma_irq_callback(struct au1550_spi *hw)
 451 {
 452         u32 stat, evnt;
 453
 454         stat = hw->regs->psc_spistat;
 455         evnt = hw->regs->psc_spievent;
 456         au_sync();
 457         if ((stat & PSC_SPISTAT_DI) == 0) {
 458                 dev_err(hw->dev, "Unexpected IRQ!\n");
 459                 return IRQ_NONE;
 460         }
 461
 462         if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
 463                                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
 464                                 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD))
 465                         != 0) {
 466                 /*
 467                  * due to an spi error we consider transfer as done,
 468                  * so mask all events until before next transfer start
 469                  * and stop the possibly running dma immediatelly
 470                  */
 471                 au1550_spi_mask_ack_all(hw);
 472                 au1xxx_dbdma_stop(hw->dma_rx_ch);
 473                 au1xxx_dbdma_stop(hw->dma_tx_ch);
 474
 475                 /* get number of transfered bytes */
 476                 hw->rx_count = hw->len - au1xxx_get_dma_residue(hw->dma_rx_ch);
 477                 hw->tx_count = hw->len - au1xxx_get_dma_residue(hw->dma_tx_ch);
 478
 479                 au1xxx_dbdma_reset(hw->dma_rx_ch);
 480                 au1xxx_dbdma_reset(hw->dma_tx_ch);
 481                 au1550_spi_reset_fifos(hw);
 482
 483                 dev_err(hw->dev,
 484                         "Unexpected SPI error: event=0x%x stat=0x%x!\n",
 485                         evnt, stat);
 486
 487                 complete(&hw->master_done);
 488                 return IRQ_HANDLED;
 489         }
 490
 491         if ((evnt & PSC_SPIEVNT_MD) != 0) {
 492                 /* transfer completed successfully */
 493                 au1550_spi_mask_ack_all(hw);
 494                 hw->rx_count = hw->len;
 495                 hw->tx_count = hw->len;
 496                 complete(&hw->master_done);
 497         }
 498         return IRQ_HANDLED;
 499 }
 500
 501
 502 /* routines to handle different word sizes in pio mode */
 503 #define AU1550_SPI_RX_WORD(size, mask)                                  \
 504 static void au1550_spi_rx_word_##size(struct au1550_spi *hw)            \
 505 {                                                                       \
 506         u32 fifoword = hw->regs->psc_spitxrx & (u32)(mask);             \
 507         au_sync();                                                      \
 508         if (hw->rx) {                                                   \
 509                 *(u##size *)hw->rx = (u##size)fifoword;                 \
 510                 hw->rx += (size) / 8;                                   \
 511         }                                                               \
 512         hw->rx_count += (size) / 8;                                     \
 513 }
 514
 515 #define AU1550_SPI_TX_WORD(size, mask)                                  \
 516 static void au1550_spi_tx_word_##size(struct au1550_spi *hw)            \
 517 {                                                                       \
 518         u32 fifoword = 0;                                               \
 519         if (hw->tx) {                                                   \
 520                 fifoword = *(u##size *)hw->tx & (u32)(mask);            \
 521                 hw->tx += (size) / 8;                                   \
 522         }                                                               \
 523         hw->tx_count += (size) / 8;                                     \
 524         if (hw->tx_count >= hw->len)                                    \
 525                 fifoword |= PSC_SPITXRX_LC;                             \
 526         hw->regs->psc_spitxrx = fifoword;                               \
 527         au_sync();                                                      \
 528 }
 529
 530 AU1550_SPI_RX_WORD(8,0xff)
 531 AU1550_SPI_RX_WORD(16,0xffff)
 532 AU1550_SPI_RX_WORD(32,0xffffff)
 533 AU1550_SPI_TX_WORD(8,0xff)
 534 AU1550_SPI_TX_WORD(16,0xffff)
 535 AU1550_SPI_TX_WORD(32,0xffffff)
 536
 537 static int au1550_spi_pio_txrxb(struct spi_device *spi, struct spi_transfer *t)
 538 {
 539         u32 stat, mask;
 540         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 541
 542         hw->tx = t->tx_buf;
 543         hw->rx = t->rx_buf;
 544         hw->len = t->len;
 545         hw->tx_count = 0;
 546         hw->rx_count = 0;
 547
 548         /* by default enable nearly all events after filling tx fifo */
 549         mask = PSC_SPIMSK_SD;
 550
 551         /* fill the transmit FIFO */
 552         while (hw->tx_count < hw->len) {
 553
 554                 hw->tx_word(hw);
 555
 556                 if (hw->tx_count >= hw->len) {
 557                         /* mask tx fifo request interrupt as we are done */
 558                         mask |= PSC_SPIMSK_TR;
 559                 }
 560
 561                 stat = hw->regs->psc_spistat;
 562                 au_sync();
 563                 if (stat & PSC_SPISTAT_TF)
 564                         break;
 565         }
 566
 567         /* enable event interrupts */
 568         hw->regs->psc_spimsk = mask;
 569         au_sync();
 570
 571         /* start the transfer */
 572         hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 573         au_sync();
 574
 575         wait_for_completion(&hw->master_done);
 576
 577         return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
 578 }
 579
 580 static irqreturn_t au1550_spi_pio_irq_callback(struct au1550_spi *hw)
 581 {
 582         int busy;
 583         u32 stat, evnt;
 584
 585         stat = hw->regs->psc_spistat;
 586         evnt = hw->regs->psc_spievent;
 587         au_sync();
 588         if ((stat & PSC_SPISTAT_DI) == 0) {
 589                 dev_err(hw->dev, "Unexpected IRQ!\n");
 590                 return IRQ_NONE;
 591         }
 592
 593         if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
 594                                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
 595                                 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD))
 596                         != 0) {
 597                 dev_err(hw->dev,
 598                         "Unexpected SPI error: event=0x%x stat=0x%x!\n",
 599                         evnt, stat);
 600                 /*
 601                  * due to an error we consider transfer as done,
 602                  * so mask all events until before next transfer start
 603                  */
 604                 au1550_spi_mask_ack_all(hw);
 605                 au1550_spi_reset_fifos(hw);
 606                 complete(&hw->master_done);
 607                 return IRQ_HANDLED;
 608         }
 609
 610         /*
 611          * while there is something to read from rx fifo
 612          * or there is a space to write to tx fifo:
 613          */
 614         do {
 615                 busy = 0;
 616                 stat = hw->regs->psc_spistat;
 617                 au_sync();
 618
 619                 if ((stat & PSC_SPISTAT_RE) == 0 && hw->rx_count < hw->len) {
 620                         hw->rx_word(hw);
 621                         /* ack the receive request event */
 622                         hw->regs->psc_spievent = PSC_SPIEVNT_RR;
 623                         au_sync();
 624                         busy = 1;
 625                 }
 626
 627                 if ((stat & PSC_SPISTAT_TF) == 0 && hw->tx_count < hw->len) {
 628                         hw->tx_word(hw);
 629                         /* ack the transmit request event */
 630                         hw->regs->psc_spievent = PSC_SPIEVNT_TR;
 631                         au_sync();
 632                         busy = 1;
 633                 }
 634         } while (busy);
 635
 636         evnt = hw->regs->psc_spievent;
 637         au_sync();
 638
 639         if (hw->rx_count >= hw->len || (evnt & PSC_SPIEVNT_MD) != 0) {
 640                 /* transfer completed successfully */
 641                 au1550_spi_mask_ack_all(hw);
 642                 complete(&hw->master_done);
 643         }
 644         return IRQ_HANDLED;
 645 }
 646
 647 static int au1550_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
 648 {
 649         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 650         return hw->txrx_bufs(spi, t);
 651 }
 652
 653 static irqreturn_t au1550_spi_irq(int irq, void *dev)
 654 {
 655         struct au1550_spi *hw = dev;
 656         return hw->irq_callback(hw);
 657 }
 658
 659 static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw)
 660 {
 661         if (bpw <= 8) {
 662                 if (hw->usedma) {
 663                         hw->txrx_bufs = &au1550_spi_dma_txrxb;
 664                         hw->irq_callback = &au1550_spi_dma_irq_callback;
 665                 } else {
 666                         hw->rx_word = &au1550_spi_rx_word_8;
 667                         hw->tx_word = &au1550_spi_tx_word_8;
 668                         hw->txrx_bufs = &au1550_spi_pio_txrxb;
 669                         hw->irq_callback = &au1550_spi_pio_irq_callback;
 670                 }
 671         } else if (bpw <= 16) {
 672                 hw->rx_word = &au1550_spi_rx_word_16;
 673                 hw->tx_word = &au1550_spi_tx_word_16;
 674                 hw->txrx_bufs = &au1550_spi_pio_txrxb;
 675                 hw->irq_callback = &au1550_spi_pio_irq_callback;
 676         } else {
 677                 hw->rx_word = &au1550_spi_rx_word_32;
 678                 hw->tx_word = &au1550_spi_tx_word_32;
 679                 hw->txrx_bufs = &au1550_spi_pio_txrxb;
 680                 hw->irq_callback = &au1550_spi_pio_irq_callback;
 681         }
 682 }
 683
 684 static void __init au1550_spi_setup_psc_as_spi(struct au1550_spi *hw)
 685 {
 686         u32 stat, cfg;
 687
 688         /* set up the PSC for SPI mode */
 689         hw->regs->psc_ctrl = PSC_CTRL_DISABLE;
 690         au_sync();
 691         hw->regs->psc_sel = PSC_SEL_PS_SPIMODE;
 692         au_sync();
 693
 694         hw->regs->psc_spicfg = 0;
 695         au_sync();
 696
 697         hw->regs->psc_ctrl = PSC_CTRL_ENABLE;
 698         au_sync();
 699
 700         do {
 701                 stat = hw->regs->psc_spistat;
 702                 au_sync();
 703         } while ((stat & PSC_SPISTAT_SR) == 0);
 704
 705
 706         cfg = hw->usedma ? 0 : PSC_SPICFG_DD_DISABLE;
 707         cfg |= PSC_SPICFG_SET_LEN(8);
 708         cfg |= PSC_SPICFG_RT_FIFO8 | PSC_SPICFG_TT_FIFO8;
 709         /* use minimal allowed brg and div values as initial setting: */
 710         cfg |= PSC_SPICFG_SET_BAUD(4) | PSC_SPICFG_SET_DIV(0);
 711
 712 #ifdef AU1550_SPI_DEBUG_LOOPBACK
 713         cfg |= PSC_SPICFG_LB;
 714 #endif
 715
 716         hw->regs->psc_spicfg = cfg;
 717         au_sync();
 718
 719         au1550_spi_mask_ack_all(hw);
 720
 721         hw->regs->psc_spicfg |= PSC_SPICFG_DE_ENABLE;
 722         au_sync();
 723
 724         do {
 725                 stat = hw->regs->psc_spistat;
 726                 au_sync();
 727         } while ((stat & PSC_SPISTAT_DR) == 0);
 728 }
 729
 730
 731 static int __init au1550_spi_probe(struct platform_device *pdev)
 732 {
 733         struct au1550_spi *hw;
 734         struct spi_master *master;
 735         int err = 0;
 736
 737         master = spi_alloc_master(&pdev->dev, sizeof(struct au1550_spi));
 738         if (master == NULL) {
 739                 dev_err(&pdev->dev, "No memory for spi_master\n");
 740                 err = -ENOMEM;
 741                 goto err_nomem;
 742         }
 743
 744         hw = spi_master_get_devdata(master);
 745
 746         hw->master = spi_master_get(master);
 747         hw->pdata = pdev->dev.platform_data;
 748         hw->dev = &pdev->dev;
 749
 750         if (hw->pdata == NULL) {
 751                 dev_err(&pdev->dev, "No platform data supplied\n");
 752                 err = -ENOENT;
 753                 goto err_no_pdata;
 754         }
 755
 756         platform_set_drvdata(pdev, hw);
 757
 758         init_completion(&hw->master_done);
 759
 760         hw->bitbang.master = hw->master;
 761         hw->bitbang.setup_transfer = au1550_spi_setupxfer;
 762         hw->bitbang.chipselect = au1550_spi_chipsel;
 763         hw->bitbang.master->setup = au1550_spi_setup;
 764         hw->bitbang.txrx_bufs = au1550_spi_txrx_bufs;
 765
 766         switch (hw->pdata->bus_num) {
 767         case 0:
 768                 hw->irq = AU1550_PSC0_INT;
 769                 hw->regs = (volatile psc_spi_t *)PSC0_BASE_ADDR;
 770                 hw->dma_rx_id = DSCR_CMD0_PSC0_RX;
 771                 hw->dma_tx_id = DSCR_CMD0_PSC0_TX;
 772                 break;
 773         case 1:
 774                 hw->irq = AU1550_PSC1_INT;
 775                 hw->regs = (volatile psc_spi_t *)PSC1_BASE_ADDR;
 776                 hw->dma_rx_id = DSCR_CMD0_PSC1_RX;
 777                 hw->dma_tx_id = DSCR_CMD0_PSC1_TX;
 778                 break;
 779         case 2:
 780                 hw->irq = AU1550_PSC2_INT;
 781                 hw->regs = (volatile psc_spi_t *)PSC2_BASE_ADDR;
 782                 hw->dma_rx_id = DSCR_CMD0_PSC2_RX;
 783                 hw->dma_tx_id = DSCR_CMD0_PSC2_TX;
 784                 break;
 785         case 3:
 786                 hw->irq = AU1550_PSC3_INT;
 787                 hw->regs = (volatile psc_spi_t *)PSC3_BASE_ADDR;
 788                 hw->dma_rx_id = DSCR_CMD0_PSC3_RX;
 789                 hw->dma_tx_id = DSCR_CMD0_PSC3_TX;
 790                 break;
 791         default:
 792                 dev_err(&pdev->dev, "Wrong bus_num of SPI\n");
 793                 err = -ENOENT;
 794                 goto err_no_pdata;
 795         }
 796
 797         if (request_mem_region((unsigned long)hw->regs, sizeof(psc_spi_t),
 798                         pdev->name) == NULL) {
 799                 dev_err(&pdev->dev, "Cannot reserve iomem region\n");
 800                 err = -ENXIO;
 801                 goto err_no_iores;
 802         }
 803
 804
 805         if (usedma) {
 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         if (hw->usedma) {
 813                 /*
 814                  * create memory device with 8 bits dev_devwidth
 815                  * needed for proper byte ordering to spi fifo
 816                  */
 817                 int memid = au1xxx_ddma_add_device(&au1550_spi_mem_dbdev);
 818                 if (!memid) {
 819                         dev_err(&pdev->dev,
 820                                 "Cannot create dma 8 bit mem device\n");
 821                         err = -ENXIO;
 822                         goto err_dma_add_dev;
 823                 }
 824
 825                 hw->dma_tx_ch = au1xxx_dbdma_chan_alloc(memid,
 826                         hw->dma_tx_id, NULL, (void *)hw);
 827                 if (hw->dma_tx_ch == 0) {
 828                         dev_err(&pdev->dev,
 829                                 "Cannot allocate tx dma channel\n");
 830                         err = -ENXIO;
 831                         goto err_no_txdma;
 832                 }
 833                 au1xxx_dbdma_set_devwidth(hw->dma_tx_ch, 8);
 834                 if (au1xxx_dbdma_ring_alloc(hw->dma_tx_ch,
 835                         AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
 836                         dev_err(&pdev->dev,
 837                                 "Cannot allocate tx dma descriptors\n");
 838                         err = -ENXIO;
 839                         goto err_no_txdma_descr;
 840                 }
 841
 842
 843                 hw->dma_rx_ch = au1xxx_dbdma_chan_alloc(hw->dma_rx_id,
 844                         memid, NULL, (void *)hw);
 845                 if (hw->dma_rx_ch == 0) {
 846                         dev_err(&pdev->dev,
 847                                 "Cannot allocate rx dma channel\n");
 848                         err = -ENXIO;
 849                         goto err_no_rxdma;
 850                 }
 851                 au1xxx_dbdma_set_devwidth(hw->dma_rx_ch, 8);
 852                 if (au1xxx_dbdma_ring_alloc(hw->dma_rx_ch,
 853                         AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
 854                         dev_err(&pdev->dev,
 855                                 "Cannot allocate rx dma descriptors\n");
 856                         err = -ENXIO;
 857                         goto err_no_rxdma_descr;
 858                 }
 859
 860                 err = au1550_spi_dma_rxtmp_alloc(hw,
 861                         AU1550_SPI_DMA_RXTMP_MINSIZE);
 862                 if (err < 0) {
 863                         dev_err(&pdev->dev,
 864                                 "Cannot allocate initial rx dma tmp buffer\n");
 865                         goto err_dma_rxtmp_alloc;
 866                 }
 867         }
 868
 869         au1550_spi_bits_handlers_set(hw, 8);
 870
 871         err = request_irq(hw->irq, au1550_spi_irq, 0, pdev->name, hw);
 872         if (err) {
 873                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
 874                 goto err_no_irq;
 875         }
 876
 877         master->bus_num = hw->pdata->bus_num;
 878         master->num_chipselect = hw->pdata->num_chipselect;
 879
 880         /*
 881          *  precompute valid range for spi freq - from au1550 datasheet:
 882          *    psc_tempclk = psc_mainclk / (2 << DIV)
 883          *    spiclk = psc_tempclk / (2 * (BRG + 1))
 884          *    BRG valid range is 4..63
 885          *    DIV valid range is 0..3
 886          *  round the min and max frequencies to values that would still
 887          *  produce valid brg and div
 888          */
 889         {
 890                 int min_div = (2 << 0) * (2 * (4 + 1));
 891                 int max_div = (2 << 3) * (2 * (63 + 1));
 892                 hw->freq_max = hw->pdata->mainclk_hz / min_div;
 893                 hw->freq_min = hw->pdata->mainclk_hz / (max_div + 1) + 1;
 894         }
 895
 896         au1550_spi_setup_psc_as_spi(hw);
 897
 898         err = spi_bitbang_start(&hw->bitbang);
 899         if (err) {
 900                 dev_err(&pdev->dev, "Failed to register SPI master\n");
 901                 goto err_register;
 902         }
 903
 904         dev_info(&pdev->dev,
 905                 "spi master registered: bus_num=%d num_chipselect=%d\n",
 906                 master->bus_num, master->num_chipselect);
 907
 908         return 0;
 909
 910 err_register:
 911         free_irq(hw->irq, hw);
 912
 913 err_no_irq:
 914         au1550_spi_dma_rxtmp_free(hw);
 915
 916 err_dma_rxtmp_alloc:
 917 err_no_rxdma_descr:
 918         if (hw->usedma)
 919                 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
 920
 921 err_no_rxdma:
 922 err_no_txdma_descr:
 923         if (hw->usedma)
 924                 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
 925
 926 err_no_txdma:
 927 err_dma_add_dev:
 928         release_mem_region((unsigned long)hw->regs, sizeof(psc_spi_t));
 929
 930 err_no_iores:
 931 err_no_pdata:
 932         spi_master_put(hw->master);
 933
 934 err_nomem:
 935         return err;
 936 }
 937
 938 static int __exit au1550_spi_remove(struct platform_device *pdev)
 939 {
 940         struct au1550_spi *hw = platform_get_drvdata(pdev);
 941
 942         dev_info(&pdev->dev, "spi master remove: bus_num=%d\n",
 943                 hw->master->bus_num);
 944
 945         spi_bitbang_stop(&hw->bitbang);
 946         free_irq(hw->irq, hw);
 947         release_mem_region((unsigned long)hw->regs, sizeof(psc_spi_t));
 948
 949         if (hw->usedma) {
 950                 au1550_spi_dma_rxtmp_free(hw);
 951                 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
 952                 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
 953         }
 954
 955         platform_set_drvdata(pdev, NULL);
 956
 957         spi_master_put(hw->master);
 958         return 0;
 959 }
 960
 961 static struct platform_driver au1550_spi_drv = {
 962         .remove = __exit_p(au1550_spi_remove),
 963         .driver = {
 964                 .name = "au1550-spi",
 965                 .owner = THIS_MODULE,
 966         },
 967 };
 968
 969 static int __init au1550_spi_init(void)
 970 {
 971         return platform_driver_probe(&au1550_spi_drv, au1550_spi_probe);
 972 }
 973 module_init(au1550_spi_init);
 974
 975 static void __exit au1550_spi_exit(void)
 976 {
 977         platform_driver_unregister(&au1550_spi_drv);
 978 }
 979 module_exit(au1550_spi_exit);
 980
 981 MODULE_DESCRIPTION("Au1550 PSC SPI Driver");
 982 MODULE_AUTHOR("Jan Nikitenko <jan.nikitenko@gmail.com>");
 983 MODULE_LICENSE("GPL");