git.oblomov.eu Git - linux-2.6/blob - drivers/spi/atmel_spi.c

   1 /*
   2  * Driver for Atmel AT32 and AT91 SPI Controllers
   3  *
   4  * Copyright (C) 2006 Atmel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/clk.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/delay.h>
  17 #include <linux/dma-mapping.h>
  18 #include <linux/err.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/spi/spi.h>
  21
  22 #include <asm/io.h>
  23 #include <mach/board.h>
  24 #include <mach/gpio.h>
  25 #include <mach/cpu.h>
  26
  27 #include "atmel_spi.h"
  28
  29 /*
  30  * The core SPI transfer engine just talks to a register bank to set up
  31  * DMA transfers; transfer queue progress is driven by IRQs.  The clock
  32  * framework provides the base clock, subdivided for each spi_device.
  33  *
  34  * Newer controllers, marked with "new_1" flag, have:
  35  *  - CR.LASTXFER
  36  *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
  37  *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
  38  *  - SPI_CSRx.CSAAT
  39  *  - SPI_CSRx.SBCR allows faster clocking
  40  */
  41 struct atmel_spi {
  42         spinlock_t              lock;
  43
  44         void __iomem            *regs;
  45         int                     irq;
  46         struct clk              *clk;
  47         struct platform_device  *pdev;
  48         unsigned                new_1:1;
  49         struct spi_device       *stay;
  50
  51         u8                      stopping;
  52         struct list_head        queue;
  53         struct spi_transfer     *current_transfer;
  54         unsigned long           current_remaining_bytes;
  55         struct spi_transfer     *next_transfer;
  56         unsigned long           next_remaining_bytes;
  57
  58         void                    *buffer;
  59         dma_addr_t              buffer_dma;
  60 };
  61
  62 #define BUFFER_SIZE             PAGE_SIZE
  63 #define INVALID_DMA_ADDRESS     0xffffffff
  64
  65 /*
  66  * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
  67  * they assume that spi slave device state will not change on deselect, so
  68  * that automagic deselection is OK.  ("NPCSx rises if no data is to be
  69  * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
  70  * controllers have CSAAT and friends.
  71  *
  72  * Since the CSAAT functionality is a bit weird on newer controllers as
  73  * well, we use GPIO to control nCSx pins on all controllers, updating
  74  * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
  75  * support active-high chipselects despite the controller's belief that
  76  * only active-low devices/systems exists.
  77  *
  78  * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
  79  * right when driven with GPIO.  ("Mode Fault does not allow more than one
  80  * Master on Chip Select 0.")  No workaround exists for that ... so for
  81  * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
  82  * and (c) will trigger that first erratum in some cases.
  83  */
  84
  85 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
  86 {
  87         unsigned gpio = (unsigned) spi->controller_data;
  88         unsigned active = spi->mode & SPI_CS_HIGH;
  89         u32 mr;
  90         int i;
  91         u32 csr;
  92         u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
  93
  94         /* Make sure clock polarity is correct */
  95         for (i = 0; i < spi->master->num_chipselect; i++) {
  96                 csr = spi_readl(as, CSR0 + 4 * i);
  97                 if ((csr ^ cpol) & SPI_BIT(CPOL))
  98                         spi_writel(as, CSR0 + 4 * i, csr ^ SPI_BIT(CPOL));
  99         }
 100
 101         mr = spi_readl(as, MR);
 102         mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
 103
 104         dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
 105                         gpio, active ? " (high)" : "",
 106                         mr);
 107
 108         if (!(cpu_is_at91rm9200() && spi->chip_select == 0))
 109                 gpio_set_value(gpio, active);
 110         spi_writel(as, MR, mr);
 111 }
 112
 113 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 114 {
 115         unsigned gpio = (unsigned) spi->controller_data;
 116         unsigned active = spi->mode & SPI_CS_HIGH;
 117         u32 mr;
 118
 119         /* only deactivate *this* device; sometimes transfers to
 120          * another device may be active when this routine is called.
 121          */
 122         mr = spi_readl(as, MR);
 123         if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
 124                 mr = SPI_BFINS(PCS, 0xf, mr);
 125                 spi_writel(as, MR, mr);
 126         }
 127
 128         dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
 129                         gpio, active ? " (low)" : "",
 130                         mr);
 131
 132         if (!(cpu_is_at91rm9200() && spi->chip_select == 0))
 133                 gpio_set_value(gpio, !active);
 134 }
 135
 136 static inline int atmel_spi_xfer_is_last(struct spi_message *msg,
 137                                         struct spi_transfer *xfer)
 138 {
 139         return msg->transfers.prev == &xfer->transfer_list;
 140 }
 141
 142 static inline int atmel_spi_xfer_can_be_chained(struct spi_transfer *xfer)
 143 {
 144         return xfer->delay_usecs == 0 && !xfer->cs_change;
 145 }
 146
 147 static void atmel_spi_next_xfer_data(struct spi_master *master,
 148                                 struct spi_transfer *xfer,
 149                                 dma_addr_t *tx_dma,
 150                                 dma_addr_t *rx_dma,
 151                                 u32 *plen)
 152 {
 153         struct atmel_spi        *as = spi_master_get_devdata(master);
 154         u32                     len = *plen;
 155
 156         /* use scratch buffer only when rx or tx data is unspecified */
 157         if (xfer->rx_buf)
 158                 *rx_dma = xfer->rx_dma + xfer->len - len;
 159         else {
 160                 *rx_dma = as->buffer_dma;
 161                 if (len > BUFFER_SIZE)
 162                         len = BUFFER_SIZE;
 163         }
 164         if (xfer->tx_buf)
 165                 *tx_dma = xfer->tx_dma + xfer->len - len;
 166         else {
 167                 *tx_dma = as->buffer_dma;
 168                 if (len > BUFFER_SIZE)
 169                         len = BUFFER_SIZE;
 170                 memset(as->buffer, 0, len);
 171                 dma_sync_single_for_device(&as->pdev->dev,
 172                                 as->buffer_dma, len, DMA_TO_DEVICE);
 173         }
 174
 175         *plen = len;
 176 }
 177
 178 /*
 179  * Submit next transfer for DMA.
 180  * lock is held, spi irq is blocked
 181  */
 182 static void atmel_spi_next_xfer(struct spi_master *master,
 183                                 struct spi_message *msg)
 184 {
 185         struct atmel_spi        *as = spi_master_get_devdata(master);
 186         struct spi_transfer     *xfer;
 187         u32                     len, remaining;
 188         u32                     ieval;
 189         dma_addr_t              tx_dma, rx_dma;
 190
 191         if (!as->current_transfer)
 192                 xfer = list_entry(msg->transfers.next,
 193                                 struct spi_transfer, transfer_list);
 194         else if (!as->next_transfer)
 195                 xfer = list_entry(as->current_transfer->transfer_list.next,
 196                                 struct spi_transfer, transfer_list);
 197         else
 198                 xfer = NULL;
 199
 200         if (xfer) {
 201                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 202
 203                 len = xfer->len;
 204                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 205                 remaining = xfer->len - len;
 206
 207                 spi_writel(as, RPR, rx_dma);
 208                 spi_writel(as, TPR, tx_dma);
 209
 210                 if (msg->spi->bits_per_word > 8)
 211                         len >>= 1;
 212                 spi_writel(as, RCR, len);
 213                 spi_writel(as, TCR, len);
 214
 215                 dev_dbg(&msg->spi->dev,
 216                         "  start xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 217                         xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 218                         xfer->rx_buf, xfer->rx_dma);
 219         } else {
 220                 xfer = as->next_transfer;
 221                 remaining = as->next_remaining_bytes;
 222         }
 223
 224         as->current_transfer = xfer;
 225         as->current_remaining_bytes = remaining;
 226
 227         if (remaining > 0)
 228                 len = remaining;
 229         else if (!atmel_spi_xfer_is_last(msg, xfer)
 230                         && atmel_spi_xfer_can_be_chained(xfer)) {
 231                 xfer = list_entry(xfer->transfer_list.next,
 232                                 struct spi_transfer, transfer_list);
 233                 len = xfer->len;
 234         } else
 235                 xfer = NULL;
 236
 237         as->next_transfer = xfer;
 238
 239         if (xfer) {
 240                 u32     total;
 241
 242                 total = len;
 243                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 244                 as->next_remaining_bytes = total - len;
 245
 246                 spi_writel(as, RNPR, rx_dma);
 247                 spi_writel(as, TNPR, tx_dma);
 248
 249                 if (msg->spi->bits_per_word > 8)
 250                         len >>= 1;
 251                 spi_writel(as, RNCR, len);
 252                 spi_writel(as, TNCR, len);
 253
 254                 dev_dbg(&msg->spi->dev,
 255                         "  next xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 256                         xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 257                         xfer->rx_buf, xfer->rx_dma);
 258                 ieval = SPI_BIT(ENDRX) | SPI_BIT(OVRES);
 259         } else {
 260                 spi_writel(as, RNCR, 0);
 261                 spi_writel(as, TNCR, 0);
 262                 ieval = SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES);
 263         }
 264
 265         /* REVISIT: We're waiting for ENDRX before we start the next
 266          * transfer because we need to handle some difficult timing
 267          * issues otherwise. If we wait for ENDTX in one transfer and
 268          * then starts waiting for ENDRX in the next, it's difficult
 269          * to tell the difference between the ENDRX interrupt we're
 270          * actually waiting for and the ENDRX interrupt of the
 271          * previous transfer.
 272          *
 273          * It should be doable, though. Just not now...
 274          */
 275         spi_writel(as, IER, ieval);
 276         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 277 }
 278
 279 static void atmel_spi_next_message(struct spi_master *master)
 280 {
 281         struct atmel_spi        *as = spi_master_get_devdata(master);
 282         struct spi_message      *msg;
 283         struct spi_device       *spi;
 284
 285         BUG_ON(as->current_transfer);
 286
 287         msg = list_entry(as->queue.next, struct spi_message, queue);
 288         spi = msg->spi;
 289
 290         dev_dbg(master->dev.parent, "start message %p for %s\n",
 291                         msg, spi->dev.bus_id);
 292
 293         /* select chip if it's not still active */
 294         if (as->stay) {
 295                 if (as->stay != spi) {
 296                         cs_deactivate(as, as->stay);
 297                         cs_activate(as, spi);
 298                 }
 299                 as->stay = NULL;
 300         } else
 301                 cs_activate(as, spi);
 302
 303         atmel_spi_next_xfer(master, msg);
 304 }
 305
 306 /*
 307  * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
 308  *  - The buffer is either valid for CPU access, else NULL
 309  *  - If the buffer is valid, so is its DMA addresss
 310  *
 311  * This driver manages the dma addresss unless message->is_dma_mapped.
 312  */
 313 static int
 314 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 315 {
 316         struct device   *dev = &as->pdev->dev;
 317
 318         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 319         if (xfer->tx_buf) {
 320                 xfer->tx_dma = dma_map_single(dev,
 321                                 (void *) xfer->tx_buf, xfer->len,
 322                                 DMA_TO_DEVICE);
 323                 if (dma_mapping_error(dev, xfer->tx_dma))
 324                         return -ENOMEM;
 325         }
 326         if (xfer->rx_buf) {
 327                 xfer->rx_dma = dma_map_single(dev,
 328                                 xfer->rx_buf, xfer->len,
 329                                 DMA_FROM_DEVICE);
 330                 if (dma_mapping_error(dev, xfer->rx_dma)) {
 331                         if (xfer->tx_buf)
 332                                 dma_unmap_single(dev,
 333                                                 xfer->tx_dma, xfer->len,
 334                                                 DMA_TO_DEVICE);
 335                         return -ENOMEM;
 336                 }
 337         }
 338         return 0;
 339 }
 340
 341 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
 342                                      struct spi_transfer *xfer)
 343 {
 344         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
 345                 dma_unmap_single(master->dev.parent, xfer->tx_dma,
 346                                  xfer->len, DMA_TO_DEVICE);
 347         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
 348                 dma_unmap_single(master->dev.parent, xfer->rx_dma,
 349                                  xfer->len, DMA_FROM_DEVICE);
 350 }
 351
 352 static void
 353 atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
 354                 struct spi_message *msg, int status, int stay)
 355 {
 356         if (!stay || status < 0)
 357                 cs_deactivate(as, msg->spi);
 358         else
 359                 as->stay = msg->spi;
 360
 361         list_del(&msg->queue);
 362         msg->status = status;
 363
 364         dev_dbg(master->dev.parent,
 365                 "xfer complete: %u bytes transferred\n",
 366                 msg->actual_length);
 367
 368         spin_unlock(&as->lock);
 369         msg->complete(msg->context);
 370         spin_lock(&as->lock);
 371
 372         as->current_transfer = NULL;
 373         as->next_transfer = NULL;
 374
 375         /* continue if needed */
 376         if (list_empty(&as->queue) || as->stopping)
 377                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 378         else
 379                 atmel_spi_next_message(master);
 380 }
 381
 382 static irqreturn_t
 383 atmel_spi_interrupt(int irq, void *dev_id)
 384 {
 385         struct spi_master       *master = dev_id;
 386         struct atmel_spi        *as = spi_master_get_devdata(master);
 387         struct spi_message      *msg;
 388         struct spi_transfer     *xfer;
 389         u32                     status, pending, imr;
 390         int                     ret = IRQ_NONE;
 391
 392         spin_lock(&as->lock);
 393
 394         xfer = as->current_transfer;
 395         msg = list_entry(as->queue.next, struct spi_message, queue);
 396
 397         imr = spi_readl(as, IMR);
 398         status = spi_readl(as, SR);
 399         pending = status & imr;
 400
 401         if (pending & SPI_BIT(OVRES)) {
 402                 int timeout;
 403
 404                 ret = IRQ_HANDLED;
 405
 406                 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
 407                                      | SPI_BIT(OVRES)));
 408
 409                 /*
 410                  * When we get an overrun, we disregard the current
 411                  * transfer. Data will not be copied back from any
 412                  * bounce buffer and msg->actual_len will not be
 413                  * updated with the last xfer.
 414                  *
 415                  * We will also not process any remaning transfers in
 416                  * the message.
 417                  *
 418                  * First, stop the transfer and unmap the DMA buffers.
 419                  */
 420                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 421                 if (!msg->is_dma_mapped)
 422                         atmel_spi_dma_unmap_xfer(master, xfer);
 423
 424                 /* REVISIT: udelay in irq is unfriendly */
 425                 if (xfer->delay_usecs)
 426                         udelay(xfer->delay_usecs);
 427
 428                 dev_warn(master->dev.parent, "overrun (%u/%u remaining)\n",
 429                          spi_readl(as, TCR), spi_readl(as, RCR));
 430
 431                 /*
 432                  * Clean up DMA registers and make sure the data
 433                  * registers are empty.
 434                  */
 435                 spi_writel(as, RNCR, 0);
 436                 spi_writel(as, TNCR, 0);
 437                 spi_writel(as, RCR, 0);
 438                 spi_writel(as, TCR, 0);
 439                 for (timeout = 1000; timeout; timeout--)
 440                         if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
 441                                 break;
 442                 if (!timeout)
 443                         dev_warn(master->dev.parent,
 444                                  "timeout waiting for TXEMPTY");
 445                 while (spi_readl(as, SR) & SPI_BIT(RDRF))
 446                         spi_readl(as, RDR);
 447
 448                 /* Clear any overrun happening while cleaning up */
 449                 spi_readl(as, SR);
 450
 451                 atmel_spi_msg_done(master, as, msg, -EIO, 0);
 452         } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
 453                 ret = IRQ_HANDLED;
 454
 455                 spi_writel(as, IDR, pending);
 456
 457                 if (as->current_remaining_bytes == 0) {
 458                         msg->actual_length += xfer->len;
 459
 460                         if (!msg->is_dma_mapped)
 461                                 atmel_spi_dma_unmap_xfer(master, xfer);
 462
 463                         /* REVISIT: udelay in irq is unfriendly */
 464                         if (xfer->delay_usecs)
 465                                 udelay(xfer->delay_usecs);
 466
 467                         if (atmel_spi_xfer_is_last(msg, xfer)) {
 468                                 /* report completed message */
 469                                 atmel_spi_msg_done(master, as, msg, 0,
 470                                                 xfer->cs_change);
 471                         } else {
 472                                 if (xfer->cs_change) {
 473                                         cs_deactivate(as, msg->spi);
 474                                         udelay(1);
 475                                         cs_activate(as, msg->spi);
 476                                 }
 477
 478                                 /*
 479                                  * Not done yet. Submit the next transfer.
 480                                  *
 481                                  * FIXME handle protocol options for xfer
 482                                  */
 483                                 atmel_spi_next_xfer(master, msg);
 484                         }
 485                 } else {
 486                         /*
 487                          * Keep going, we still have data to send in
 488                          * the current transfer.
 489                          */
 490                         atmel_spi_next_xfer(master, msg);
 491                 }
 492         }
 493
 494         spin_unlock(&as->lock);
 495
 496         return ret;
 497 }
 498
 499 /* the spi->mode bits understood by this driver: */
 500 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 501
 502 static int atmel_spi_setup(struct spi_device *spi)
 503 {
 504         struct atmel_spi        *as;
 505         u32                     scbr, csr;
 506         unsigned int            bits = spi->bits_per_word;
 507         unsigned long           bus_hz;
 508         unsigned int            npcs_pin;
 509         int                     ret;
 510
 511         as = spi_master_get_devdata(spi->master);
 512
 513         if (as->stopping)
 514                 return -ESHUTDOWN;
 515
 516         if (spi->chip_select > spi->master->num_chipselect) {
 517                 dev_dbg(&spi->dev,
 518                                 "setup: invalid chipselect %u (%u defined)\n",
 519                                 spi->chip_select, spi->master->num_chipselect);
 520                 return -EINVAL;
 521         }
 522
 523         if (bits == 0)
 524                 bits = 8;
 525         if (bits < 8 || bits > 16) {
 526                 dev_dbg(&spi->dev,
 527                                 "setup: invalid bits_per_word %u (8 to 16)\n",
 528                                 bits);
 529                 return -EINVAL;
 530         }
 531
 532         if (spi->mode & ~MODEBITS) {
 533                 dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
 534                         spi->mode & ~MODEBITS);
 535                 return -EINVAL;
 536         }
 537
 538         /* see notes above re chipselect */
 539         if (cpu_is_at91rm9200()
 540                         && spi->chip_select == 0
 541                         && (spi->mode & SPI_CS_HIGH)) {
 542                 dev_dbg(&spi->dev, "setup: can't be active-high\n");
 543                 return -EINVAL;
 544         }
 545
 546         /*
 547          * Pre-new_1 chips start out at half the peripheral
 548          * bus speed.
 549          */
 550         bus_hz = clk_get_rate(as->clk);
 551         if (!as->new_1)
 552                 bus_hz /= 2;
 553
 554         if (spi->max_speed_hz) {
 555                 /*
 556                  * Calculate the lowest divider that satisfies the
 557                  * constraint, assuming div32/fdiv/mbz == 0.
 558                  */
 559                 scbr = DIV_ROUND_UP(bus_hz, spi->max_speed_hz);
 560
 561                 /*
 562                  * If the resulting divider doesn't fit into the
 563                  * register bitfield, we can't satisfy the constraint.
 564                  */
 565                 if (scbr >= (1 << SPI_SCBR_SIZE)) {
 566                         dev_dbg(&spi->dev,
 567                                 "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
 568                                 spi->max_speed_hz, scbr, bus_hz/255);
 569                         return -EINVAL;
 570                 }
 571         } else
 572                 /* speed zero means "as slow as possible" */
 573                 scbr = 0xff;
 574
 575         csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
 576         if (spi->mode & SPI_CPOL)
 577                 csr |= SPI_BIT(CPOL);
 578         if (!(spi->mode & SPI_CPHA))
 579                 csr |= SPI_BIT(NCPHA);
 580
 581         /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
 582          *
 583          * DLYBCT would add delays between words, slowing down transfers.
 584          * It could potentially be useful to cope with DMA bottlenecks, but
 585          * in those cases it's probably best to just use a lower bitrate.
 586          */
 587         csr |= SPI_BF(DLYBS, 0);
 588         csr |= SPI_BF(DLYBCT, 0);
 589
 590         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
 591         npcs_pin = (unsigned int)spi->controller_data;
 592         if (!spi->controller_state) {
 593                 ret = gpio_request(npcs_pin, spi->dev.bus_id);
 594                 if (ret)
 595                         return ret;
 596                 spi->controller_state = (void *)npcs_pin;
 597                 gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
 598         } else {
 599                 unsigned long           flags;
 600
 601                 spin_lock_irqsave(&as->lock, flags);
 602                 if (as->stay == spi)
 603                         as->stay = NULL;
 604                 cs_deactivate(as, spi);
 605                 spin_unlock_irqrestore(&as->lock, flags);
 606         }
 607
 608         dev_dbg(&spi->dev,
 609                 "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
 610                 bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);
 611
 612         spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 613
 614         return 0;
 615 }
 616
 617 static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
 618 {
 619         struct atmel_spi        *as;
 620         struct spi_transfer     *xfer;
 621         unsigned long           flags;
 622         struct device           *controller = spi->master->dev.parent;
 623
 624         as = spi_master_get_devdata(spi->master);
 625
 626         dev_dbg(controller, "new message %p submitted for %s\n",
 627                         msg, spi->dev.bus_id);
 628
 629         if (unlikely(list_empty(&msg->transfers)
 630                         || !spi->max_speed_hz))
 631                 return -EINVAL;
 632
 633         if (as->stopping)
 634                 return -ESHUTDOWN;
 635
 636         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 637                 if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
 638                         dev_dbg(&spi->dev, "missing rx or tx buf\n");
 639                         return -EINVAL;
 640                 }
 641
 642                 /* FIXME implement these protocol options!! */
 643                 if (xfer->bits_per_word || xfer->speed_hz) {
 644                         dev_dbg(&spi->dev, "no protocol options yet\n");
 645                         return -ENOPROTOOPT;
 646                 }
 647
 648                 /*
 649                  * DMA map early, for performance (empties dcache ASAP) and
 650                  * better fault reporting.  This is a DMA-only driver.
 651                  *
 652                  * NOTE that if dma_unmap_single() ever starts to do work on
 653                  * platforms supported by this driver, we would need to clean
 654                  * up mappings for previously-mapped transfers.
 655                  */
 656                 if (!msg->is_dma_mapped) {
 657                         if (atmel_spi_dma_map_xfer(as, xfer) < 0)
 658                                 return -ENOMEM;
 659                 }
 660         }
 661
 662 #ifdef VERBOSE
 663         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 664                 dev_dbg(controller,
 665                         "  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 666                         xfer, xfer->len,
 667                         xfer->tx_buf, xfer->tx_dma,
 668                         xfer->rx_buf, xfer->rx_dma);
 669         }
 670 #endif
 671
 672         msg->status = -EINPROGRESS;
 673         msg->actual_length = 0;
 674
 675         spin_lock_irqsave(&as->lock, flags);
 676         list_add_tail(&msg->queue, &as->queue);
 677         if (!as->current_transfer)
 678                 atmel_spi_next_message(spi->master);
 679         spin_unlock_irqrestore(&as->lock, flags);
 680
 681         return 0;
 682 }
 683
 684 static void atmel_spi_cleanup(struct spi_device *spi)
 685 {
 686         struct atmel_spi        *as = spi_master_get_devdata(spi->master);
 687         unsigned                gpio = (unsigned) spi->controller_data;
 688         unsigned long           flags;
 689
 690         if (!spi->controller_state)
 691                 return;
 692
 693         spin_lock_irqsave(&as->lock, flags);
 694         if (as->stay == spi) {
 695                 as->stay = NULL;
 696                 cs_deactivate(as, spi);
 697         }
 698         spin_unlock_irqrestore(&as->lock, flags);
 699
 700         gpio_free(gpio);
 701 }
 702
 703 /*-------------------------------------------------------------------------*/
 704
 705 static int __init atmel_spi_probe(struct platform_device *pdev)
 706 {
 707         struct resource         *regs;
 708         int                     irq;
 709         struct clk              *clk;
 710         int                     ret;
 711         struct spi_master       *master;
 712         struct atmel_spi        *as;
 713
 714         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 715         if (!regs)
 716                 return -ENXIO;
 717
 718         irq = platform_get_irq(pdev, 0);
 719         if (irq < 0)
 720                 return irq;
 721
 722         clk = clk_get(&pdev->dev, "spi_clk");
 723         if (IS_ERR(clk))
 724                 return PTR_ERR(clk);
 725
 726         /* setup spi core then atmel-specific driver state */
 727         ret = -ENOMEM;
 728         master = spi_alloc_master(&pdev->dev, sizeof *as);
 729         if (!master)
 730                 goto out_free;
 731
 732         master->bus_num = pdev->id;
 733         master->num_chipselect = 4;
 734         master->setup = atmel_spi_setup;
 735         master->transfer = atmel_spi_transfer;
 736         master->cleanup = atmel_spi_cleanup;
 737         platform_set_drvdata(pdev, master);
 738
 739         as = spi_master_get_devdata(master);
 740
 741         /*
 742          * Scratch buffer is used for throwaway rx and tx data.
 743          * It's coherent to minimize dcache pollution.
 744          */
 745         as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
 746                                         &as->buffer_dma, GFP_KERNEL);
 747         if (!as->buffer)
 748                 goto out_free;
 749
 750         spin_lock_init(&as->lock);
 751         INIT_LIST_HEAD(&as->queue);
 752         as->pdev = pdev;
 753         as->regs = ioremap(regs->start, (regs->end - regs->start) + 1);
 754         if (!as->regs)
 755                 goto out_free_buffer;
 756         as->irq = irq;
 757         as->clk = clk;
 758         if (!cpu_is_at91rm9200())
 759                 as->new_1 = 1;
 760
 761         ret = request_irq(irq, atmel_spi_interrupt, 0,
 762                         pdev->dev.bus_id, master);
 763         if (ret)
 764                 goto out_unmap_regs;
 765
 766         /* Initialize the hardware */
 767         clk_enable(clk);
 768         spi_writel(as, CR, SPI_BIT(SWRST));
 769         spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
 770         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 771         spi_writel(as, CR, SPI_BIT(SPIEN));
 772
 773         /* go! */
 774         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
 775                         (unsigned long)regs->start, irq);
 776
 777         ret = spi_register_master(master);
 778         if (ret)
 779                 goto out_reset_hw;
 780
 781         return 0;
 782
 783 out_reset_hw:
 784         spi_writel(as, CR, SPI_BIT(SWRST));
 785         clk_disable(clk);
 786         free_irq(irq, master);
 787 out_unmap_regs:
 788         iounmap(as->regs);
 789 out_free_buffer:
 790         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 791                         as->buffer_dma);
 792 out_free:
 793         clk_put(clk);
 794         spi_master_put(master);
 795         return ret;
 796 }
 797
 798 static int __exit atmel_spi_remove(struct platform_device *pdev)
 799 {
 800         struct spi_master       *master = platform_get_drvdata(pdev);
 801         struct atmel_spi        *as = spi_master_get_devdata(master);
 802         struct spi_message      *msg;
 803
 804         /* reset the hardware and block queue progress */
 805         spin_lock_irq(&as->lock);
 806         as->stopping = 1;
 807         spi_writel(as, CR, SPI_BIT(SWRST));
 808         spi_readl(as, SR);
 809         spin_unlock_irq(&as->lock);
 810
 811         /* Terminate remaining queued transfers */
 812         list_for_each_entry(msg, &as->queue, queue) {
 813                 /* REVISIT unmapping the dma is a NOP on ARM and AVR32
 814                  * but we shouldn't depend on that...
 815                  */
 816                 msg->status = -ESHUTDOWN;
 817                 msg->complete(msg->context);
 818         }
 819
 820         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 821                         as->buffer_dma);
 822
 823         clk_disable(as->clk);
 824         clk_put(as->clk);
 825         free_irq(as->irq, master);
 826         iounmap(as->regs);
 827
 828         spi_unregister_master(master);
 829
 830         return 0;
 831 }
 832
 833 #ifdef  CONFIG_PM
 834
 835 static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
 836 {
 837         struct spi_master       *master = platform_get_drvdata(pdev);
 838         struct atmel_spi        *as = spi_master_get_devdata(master);
 839
 840         clk_disable(as->clk);
 841         return 0;
 842 }
 843
 844 static int atmel_spi_resume(struct platform_device *pdev)
 845 {
 846         struct spi_master       *master = platform_get_drvdata(pdev);
 847         struct atmel_spi        *as = spi_master_get_devdata(master);
 848
 849         clk_enable(as->clk);
 850         return 0;
 851 }
 852
 853 #else
 854 #define atmel_spi_suspend       NULL
 855 #define atmel_spi_resume        NULL
 856 #endif
 857
 858
 859 static struct platform_driver atmel_spi_driver = {
 860         .driver         = {
 861                 .name   = "atmel_spi",
 862                 .owner  = THIS_MODULE,
 863         },
 864         .suspend        = atmel_spi_suspend,
 865         .resume         = atmel_spi_resume,
 866         .remove         = __exit_p(atmel_spi_remove),
 867 };
 868
 869 static int __init atmel_spi_init(void)
 870 {
 871         return platform_driver_probe(&atmel_spi_driver, atmel_spi_probe);
 872 }
 873 module_init(atmel_spi_init);
 874
 875 static void __exit atmel_spi_exit(void)
 876 {
 877         platform_driver_unregister(&atmel_spi_driver);
 878 }
 879 module_exit(atmel_spi_exit);
 880
 881 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
 882 MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
 883 MODULE_LICENSE("GPL");
 884 MODULE_ALIAS("platform:atmel_spi");