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 <asm/arch/board.h>
  24 #include <asm/arch/gpio.h>
  25 #include <asm/arch/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, total;
 188         dma_addr_t              tx_dma, rx_dma;
 189
 190         if (!as->current_transfer)
 191                 xfer = list_entry(msg->transfers.next,
 192                                 struct spi_transfer, transfer_list);
 193         else if (!as->next_transfer)
 194                 xfer = list_entry(as->current_transfer->transfer_list.next,
 195                                 struct spi_transfer, transfer_list);
 196         else
 197                 xfer = NULL;
 198
 199         if (xfer) {
 200                 len = xfer->len;
 201                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 202                 remaining = xfer->len - len;
 203
 204                 spi_writel(as, RPR, rx_dma);
 205                 spi_writel(as, TPR, tx_dma);
 206
 207                 if (msg->spi->bits_per_word > 8)
 208                         len >>= 1;
 209                 spi_writel(as, RCR, len);
 210                 spi_writel(as, TCR, len);
 211
 212                 dev_dbg(&msg->spi->dev,
 213                         "  start xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 214                         xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 215                         xfer->rx_buf, xfer->rx_dma);
 216         } else {
 217                 xfer = as->next_transfer;
 218                 remaining = as->next_remaining_bytes;
 219         }
 220
 221         as->current_transfer = xfer;
 222         as->current_remaining_bytes = remaining;
 223
 224         if (remaining > 0)
 225                 len = remaining;
 226         else if (!atmel_spi_xfer_is_last(msg, xfer)
 227                         && atmel_spi_xfer_can_be_chained(xfer)) {
 228                 xfer = list_entry(xfer->transfer_list.next,
 229                                 struct spi_transfer, transfer_list);
 230                 len = xfer->len;
 231         } else
 232                 xfer = NULL;
 233
 234         as->next_transfer = xfer;
 235
 236         if (xfer) {
 237                 total = len;
 238                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 239                 as->next_remaining_bytes = total - len;
 240
 241                 spi_writel(as, RNPR, rx_dma);
 242                 spi_writel(as, TNPR, tx_dma);
 243
 244                 if (msg->spi->bits_per_word > 8)
 245                         len >>= 1;
 246                 spi_writel(as, RNCR, len);
 247                 spi_writel(as, TNCR, len);
 248
 249                 dev_dbg(&msg->spi->dev,
 250                         "  next xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 251                         xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 252                         xfer->rx_buf, xfer->rx_dma);
 253         } else {
 254                 spi_writel(as, RNCR, 0);
 255                 spi_writel(as, TNCR, 0);
 256         }
 257
 258         /* REVISIT: We're waiting for ENDRX before we start the next
 259          * transfer because we need to handle some difficult timing
 260          * issues otherwise. If we wait for ENDTX in one transfer and
 261          * then starts waiting for ENDRX in the next, it's difficult
 262          * to tell the difference between the ENDRX interrupt we're
 263          * actually waiting for and the ENDRX interrupt of the
 264          * previous transfer.
 265          *
 266          * It should be doable, though. Just not now...
 267          */
 268         spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
 269         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 270 }
 271
 272 static void atmel_spi_next_message(struct spi_master *master)
 273 {
 274         struct atmel_spi        *as = spi_master_get_devdata(master);
 275         struct spi_message      *msg;
 276         struct spi_device       *spi;
 277
 278         BUG_ON(as->current_transfer);
 279
 280         msg = list_entry(as->queue.next, struct spi_message, queue);
 281         spi = msg->spi;
 282
 283         dev_dbg(master->dev.parent, "start message %p for %s\n",
 284                         msg, spi->dev.bus_id);
 285
 286         /* select chip if it's not still active */
 287         if (as->stay) {
 288                 if (as->stay != spi) {
 289                         cs_deactivate(as, as->stay);
 290                         cs_activate(as, spi);
 291                 }
 292                 as->stay = NULL;
 293         } else
 294                 cs_activate(as, spi);
 295
 296         atmel_spi_next_xfer(master, msg);
 297 }
 298
 299 /*
 300  * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
 301  *  - The buffer is either valid for CPU access, else NULL
 302  *  - If the buffer is valid, so is its DMA addresss
 303  *
 304  * This driver manages the dma addresss unless message->is_dma_mapped.
 305  */
 306 static int
 307 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 308 {
 309         struct device   *dev = &as->pdev->dev;
 310
 311         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 312         if (xfer->tx_buf) {
 313                 xfer->tx_dma = dma_map_single(dev,
 314                                 (void *) xfer->tx_buf, xfer->len,
 315                                 DMA_TO_DEVICE);
 316                 if (dma_mapping_error(xfer->tx_dma))
 317                         return -ENOMEM;
 318         }
 319         if (xfer->rx_buf) {
 320                 xfer->rx_dma = dma_map_single(dev,
 321                                 xfer->rx_buf, xfer->len,
 322                                 DMA_FROM_DEVICE);
 323                 if (dma_mapping_error(xfer->rx_dma)) {
 324                         if (xfer->tx_buf)
 325                                 dma_unmap_single(dev,
 326                                                 xfer->tx_dma, xfer->len,
 327                                                 DMA_TO_DEVICE);
 328                         return -ENOMEM;
 329                 }
 330         }
 331         return 0;
 332 }
 333
 334 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
 335                                      struct spi_transfer *xfer)
 336 {
 337         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
 338                 dma_unmap_single(master->dev.parent, xfer->tx_dma,
 339                                  xfer->len, DMA_TO_DEVICE);
 340         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
 341                 dma_unmap_single(master->dev.parent, xfer->rx_dma,
 342                                  xfer->len, DMA_FROM_DEVICE);
 343 }
 344
 345 static void
 346 atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
 347                 struct spi_message *msg, int status, int stay)
 348 {
 349         if (!stay || status < 0)
 350                 cs_deactivate(as, msg->spi);
 351         else
 352                 as->stay = msg->spi;
 353
 354         list_del(&msg->queue);
 355         msg->status = status;
 356
 357         dev_dbg(master->dev.parent,
 358                 "xfer complete: %u bytes transferred\n",
 359                 msg->actual_length);
 360
 361         spin_unlock(&as->lock);
 362         msg->complete(msg->context);
 363         spin_lock(&as->lock);
 364
 365         as->current_transfer = NULL;
 366         as->next_transfer = NULL;
 367
 368         /* continue if needed */
 369         if (list_empty(&as->queue) || as->stopping)
 370                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 371         else
 372                 atmel_spi_next_message(master);
 373 }
 374
 375 static irqreturn_t
 376 atmel_spi_interrupt(int irq, void *dev_id)
 377 {
 378         struct spi_master       *master = dev_id;
 379         struct atmel_spi        *as = spi_master_get_devdata(master);
 380         struct spi_message      *msg;
 381         struct spi_transfer     *xfer;
 382         u32                     status, pending, imr;
 383         int                     ret = IRQ_NONE;
 384
 385         spin_lock(&as->lock);
 386
 387         xfer = as->current_transfer;
 388         msg = list_entry(as->queue.next, struct spi_message, queue);
 389
 390         imr = spi_readl(as, IMR);
 391         status = spi_readl(as, SR);
 392         pending = status & imr;
 393
 394         if (pending & SPI_BIT(OVRES)) {
 395                 int timeout;
 396
 397                 ret = IRQ_HANDLED;
 398
 399                 spi_writel(as, IDR, (SPI_BIT(ENDTX) | SPI_BIT(ENDRX)
 400                                      | SPI_BIT(OVRES)));
 401
 402                 /*
 403                  * When we get an overrun, we disregard the current
 404                  * transfer. Data will not be copied back from any
 405                  * bounce buffer and msg->actual_len will not be
 406                  * updated with the last xfer.
 407                  *
 408                  * We will also not process any remaning transfers in
 409                  * the message.
 410                  *
 411                  * First, stop the transfer and unmap the DMA buffers.
 412                  */
 413                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 414                 if (!msg->is_dma_mapped)
 415                         atmel_spi_dma_unmap_xfer(master, xfer);
 416
 417                 /* REVISIT: udelay in irq is unfriendly */
 418                 if (xfer->delay_usecs)
 419                         udelay(xfer->delay_usecs);
 420
 421                 dev_warn(master->dev.parent, "fifo overrun (%u/%u remaining)\n",
 422                          spi_readl(as, TCR), spi_readl(as, RCR));
 423
 424                 /*
 425                  * Clean up DMA registers and make sure the data
 426                  * registers are empty.
 427                  */
 428                 spi_writel(as, RNCR, 0);
 429                 spi_writel(as, TNCR, 0);
 430                 spi_writel(as, RCR, 0);
 431                 spi_writel(as, TCR, 0);
 432                 for (timeout = 1000; timeout; timeout--)
 433                         if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
 434                                 break;
 435                 if (!timeout)
 436                         dev_warn(master->dev.parent,
 437                                  "timeout waiting for TXEMPTY");
 438                 while (spi_readl(as, SR) & SPI_BIT(RDRF))
 439                         spi_readl(as, RDR);
 440
 441                 /* Clear any overrun happening while cleaning up */
 442                 spi_readl(as, SR);
 443
 444                 atmel_spi_msg_done(master, as, msg, -EIO, 0);
 445         } else if (pending & SPI_BIT(ENDRX)) {
 446                 ret = IRQ_HANDLED;
 447
 448                 spi_writel(as, IDR, pending);
 449
 450                 if (as->current_remaining_bytes == 0) {
 451                         msg->actual_length += xfer->len;
 452
 453                         if (!msg->is_dma_mapped)
 454                                 atmel_spi_dma_unmap_xfer(master, xfer);
 455
 456                         /* REVISIT: udelay in irq is unfriendly */
 457                         if (xfer->delay_usecs)
 458                                 udelay(xfer->delay_usecs);
 459
 460                         if (atmel_spi_xfer_is_last(msg, xfer)) {
 461                                 /* report completed message */
 462                                 atmel_spi_msg_done(master, as, msg, 0,
 463                                                 xfer->cs_change);
 464                         } else {
 465                                 if (xfer->cs_change) {
 466                                         cs_deactivate(as, msg->spi);
 467                                         udelay(1);
 468                                         cs_activate(as, msg->spi);
 469                                 }
 470
 471                                 /*
 472                                  * Not done yet. Submit the next transfer.
 473                                  *
 474                                  * FIXME handle protocol options for xfer
 475                                  */
 476                                 atmel_spi_next_xfer(master, msg);
 477                         }
 478                 } else {
 479                         /*
 480                          * Keep going, we still have data to send in
 481                          * the current transfer.
 482                          */
 483                         atmel_spi_next_xfer(master, msg);
 484                 }
 485         }
 486
 487         spin_unlock(&as->lock);
 488
 489         return ret;
 490 }
 491
 492 /* the spi->mode bits understood by this driver: */
 493 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 494
 495 static int atmel_spi_setup(struct spi_device *spi)
 496 {
 497         struct atmel_spi        *as;
 498         u32                     scbr, csr;
 499         unsigned int            bits = spi->bits_per_word;
 500         unsigned long           bus_hz, sck_hz;
 501         unsigned int            npcs_pin;
 502         int                     ret;
 503
 504         as = spi_master_get_devdata(spi->master);
 505
 506         if (as->stopping)
 507                 return -ESHUTDOWN;
 508
 509         if (spi->chip_select > spi->master->num_chipselect) {
 510                 dev_dbg(&spi->dev,
 511                                 "setup: invalid chipselect %u (%u defined)\n",
 512                                 spi->chip_select, spi->master->num_chipselect);
 513                 return -EINVAL;
 514         }
 515
 516         if (bits == 0)
 517                 bits = 8;
 518         if (bits < 8 || bits > 16) {
 519                 dev_dbg(&spi->dev,
 520                                 "setup: invalid bits_per_word %u (8 to 16)\n",
 521                                 bits);
 522                 return -EINVAL;
 523         }
 524
 525         if (spi->mode & ~MODEBITS) {
 526                 dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
 527                         spi->mode & ~MODEBITS);
 528                 return -EINVAL;
 529         }
 530
 531         /* see notes above re chipselect */
 532         if (cpu_is_at91rm9200()
 533                         && spi->chip_select == 0
 534                         && (spi->mode & SPI_CS_HIGH)) {
 535                 dev_dbg(&spi->dev, "setup: can't be active-high\n");
 536                 return -EINVAL;
 537         }
 538
 539         /* speed zero convention is used by some upper layers */
 540         bus_hz = clk_get_rate(as->clk);
 541         if (spi->max_speed_hz) {
 542                 /* assume div32/fdiv/mbz == 0 */
 543                 if (!as->new_1)
 544                         bus_hz /= 2;
 545                 scbr = ((bus_hz + spi->max_speed_hz - 1)
 546                         / spi->max_speed_hz);
 547                 if (scbr >= (1 << SPI_SCBR_SIZE)) {
 548                         dev_dbg(&spi->dev,
 549                                 "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
 550                                 spi->max_speed_hz, scbr, bus_hz/255);
 551                         return -EINVAL;
 552                 }
 553         } else
 554                 scbr = 0xff;
 555         sck_hz = bus_hz / scbr;
 556
 557         csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
 558         if (spi->mode & SPI_CPOL)
 559                 csr |= SPI_BIT(CPOL);
 560         if (!(spi->mode & SPI_CPHA))
 561                 csr |= SPI_BIT(NCPHA);
 562
 563         /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
 564          *
 565          * DLYBCT would add delays between words, slowing down transfers.
 566          * It could potentially be useful to cope with DMA bottlenecks, but
 567          * in those cases it's probably best to just use a lower bitrate.
 568          */
 569         csr |= SPI_BF(DLYBS, 0);
 570         csr |= SPI_BF(DLYBCT, 0);
 571
 572         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
 573         npcs_pin = (unsigned int)spi->controller_data;
 574         if (!spi->controller_state) {
 575                 ret = gpio_request(npcs_pin, spi->dev.bus_id);
 576                 if (ret)
 577                         return ret;
 578                 spi->controller_state = (void *)npcs_pin;
 579                 gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
 580         } else {
 581                 unsigned long           flags;
 582
 583                 spin_lock_irqsave(&as->lock, flags);
 584                 if (as->stay == spi)
 585                         as->stay = NULL;
 586                 cs_deactivate(as, spi);
 587                 spin_unlock_irqrestore(&as->lock, flags);
 588         }
 589
 590         dev_dbg(&spi->dev,
 591                 "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
 592                 sck_hz, bits, spi->mode, spi->chip_select, csr);
 593
 594         spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 595
 596         return 0;
 597 }
 598
 599 static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
 600 {
 601         struct atmel_spi        *as;
 602         struct spi_transfer     *xfer;
 603         unsigned long           flags;
 604         struct device           *controller = spi->master->dev.parent;
 605
 606         as = spi_master_get_devdata(spi->master);
 607
 608         dev_dbg(controller, "new message %p submitted for %s\n",
 609                         msg, spi->dev.bus_id);
 610
 611         if (unlikely(list_empty(&msg->transfers)
 612                         || !spi->max_speed_hz))
 613                 return -EINVAL;
 614
 615         if (as->stopping)
 616                 return -ESHUTDOWN;
 617
 618         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 619                 if (!(xfer->tx_buf || xfer->rx_buf)) {
 620                         dev_dbg(&spi->dev, "missing rx or tx buf\n");
 621                         return -EINVAL;
 622                 }
 623
 624                 /* FIXME implement these protocol options!! */
 625                 if (xfer->bits_per_word || xfer->speed_hz) {
 626                         dev_dbg(&spi->dev, "no protocol options yet\n");
 627                         return -ENOPROTOOPT;
 628                 }
 629
 630                 /*
 631                  * DMA map early, for performance (empties dcache ASAP) and
 632                  * better fault reporting.  This is a DMA-only driver.
 633                  *
 634                  * NOTE that if dma_unmap_single() ever starts to do work on
 635                  * platforms supported by this driver, we would need to clean
 636                  * up mappings for previously-mapped transfers.
 637                  */
 638                 if (!msg->is_dma_mapped) {
 639                         if (atmel_spi_dma_map_xfer(as, xfer) < 0)
 640                                 return -ENOMEM;
 641                 }
 642         }
 643
 644 #ifdef VERBOSE
 645         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 646                 dev_dbg(controller,
 647                         "  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 648                         xfer, xfer->len,
 649                         xfer->tx_buf, xfer->tx_dma,
 650                         xfer->rx_buf, xfer->rx_dma);
 651         }
 652 #endif
 653
 654         msg->status = -EINPROGRESS;
 655         msg->actual_length = 0;
 656
 657         spin_lock_irqsave(&as->lock, flags);
 658         list_add_tail(&msg->queue, &as->queue);
 659         if (!as->current_transfer)
 660                 atmel_spi_next_message(spi->master);
 661         spin_unlock_irqrestore(&as->lock, flags);
 662
 663         return 0;
 664 }
 665
 666 static void atmel_spi_cleanup(struct spi_device *spi)
 667 {
 668         struct atmel_spi        *as = spi_master_get_devdata(spi->master);
 669         unsigned                gpio = (unsigned) spi->controller_data;
 670         unsigned long           flags;
 671
 672         if (!spi->controller_state)
 673                 return;
 674
 675         spin_lock_irqsave(&as->lock, flags);
 676         if (as->stay == spi) {
 677                 as->stay = NULL;
 678                 cs_deactivate(as, spi);
 679         }
 680         spin_unlock_irqrestore(&as->lock, flags);
 681
 682         gpio_free(gpio);
 683 }
 684
 685 /*-------------------------------------------------------------------------*/
 686
 687 static int __init atmel_spi_probe(struct platform_device *pdev)
 688 {
 689         struct resource         *regs;
 690         int                     irq;
 691         struct clk              *clk;
 692         int                     ret;
 693         struct spi_master       *master;
 694         struct atmel_spi        *as;
 695
 696         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 697         if (!regs)
 698                 return -ENXIO;
 699
 700         irq = platform_get_irq(pdev, 0);
 701         if (irq < 0)
 702                 return irq;
 703
 704         clk = clk_get(&pdev->dev, "spi_clk");
 705         if (IS_ERR(clk))
 706                 return PTR_ERR(clk);
 707
 708         /* setup spi core then atmel-specific driver state */
 709         ret = -ENOMEM;
 710         master = spi_alloc_master(&pdev->dev, sizeof *as);
 711         if (!master)
 712                 goto out_free;
 713
 714         master->bus_num = pdev->id;
 715         master->num_chipselect = 4;
 716         master->setup = atmel_spi_setup;
 717         master->transfer = atmel_spi_transfer;
 718         master->cleanup = atmel_spi_cleanup;
 719         platform_set_drvdata(pdev, master);
 720
 721         as = spi_master_get_devdata(master);
 722
 723         /*
 724          * Scratch buffer is used for throwaway rx and tx data.
 725          * It's coherent to minimize dcache pollution.
 726          */
 727         as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
 728                                         &as->buffer_dma, GFP_KERNEL);
 729         if (!as->buffer)
 730                 goto out_free;
 731
 732         spin_lock_init(&as->lock);
 733         INIT_LIST_HEAD(&as->queue);
 734         as->pdev = pdev;
 735         as->regs = ioremap(regs->start, (regs->end - regs->start) + 1);
 736         if (!as->regs)
 737                 goto out_free_buffer;
 738         as->irq = irq;
 739         as->clk = clk;
 740         if (!cpu_is_at91rm9200())
 741                 as->new_1 = 1;
 742
 743         ret = request_irq(irq, atmel_spi_interrupt, 0,
 744                         pdev->dev.bus_id, master);
 745         if (ret)
 746                 goto out_unmap_regs;
 747
 748         /* Initialize the hardware */
 749         clk_enable(clk);
 750         spi_writel(as, CR, SPI_BIT(SWRST));
 751         spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
 752         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 753         spi_writel(as, CR, SPI_BIT(SPIEN));
 754
 755         /* go! */
 756         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
 757                         (unsigned long)regs->start, irq);
 758
 759         ret = spi_register_master(master);
 760         if (ret)
 761                 goto out_reset_hw;
 762
 763         return 0;
 764
 765 out_reset_hw:
 766         spi_writel(as, CR, SPI_BIT(SWRST));
 767         clk_disable(clk);
 768         free_irq(irq, master);
 769 out_unmap_regs:
 770         iounmap(as->regs);
 771 out_free_buffer:
 772         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 773                         as->buffer_dma);
 774 out_free:
 775         clk_put(clk);
 776         spi_master_put(master);
 777         return ret;
 778 }
 779
 780 static int __exit atmel_spi_remove(struct platform_device *pdev)
 781 {
 782         struct spi_master       *master = platform_get_drvdata(pdev);
 783         struct atmel_spi        *as = spi_master_get_devdata(master);
 784         struct spi_message      *msg;
 785
 786         /* reset the hardware and block queue progress */
 787         spin_lock_irq(&as->lock);
 788         as->stopping = 1;
 789         spi_writel(as, CR, SPI_BIT(SWRST));
 790         spi_readl(as, SR);
 791         spin_unlock_irq(&as->lock);
 792
 793         /* Terminate remaining queued transfers */
 794         list_for_each_entry(msg, &as->queue, queue) {
 795                 /* REVISIT unmapping the dma is a NOP on ARM and AVR32
 796                  * but we shouldn't depend on that...
 797                  */
 798                 msg->status = -ESHUTDOWN;
 799                 msg->complete(msg->context);
 800         }
 801
 802         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 803                         as->buffer_dma);
 804
 805         clk_disable(as->clk);
 806         clk_put(as->clk);
 807         free_irq(as->irq, master);
 808         iounmap(as->regs);
 809
 810         spi_unregister_master(master);
 811
 812         return 0;
 813 }
 814
 815 #ifdef  CONFIG_PM
 816
 817 static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
 818 {
 819         struct spi_master       *master = platform_get_drvdata(pdev);
 820         struct atmel_spi        *as = spi_master_get_devdata(master);
 821
 822         clk_disable(as->clk);
 823         return 0;
 824 }
 825
 826 static int atmel_spi_resume(struct platform_device *pdev)
 827 {
 828         struct spi_master       *master = platform_get_drvdata(pdev);
 829         struct atmel_spi        *as = spi_master_get_devdata(master);
 830
 831         clk_enable(as->clk);
 832         return 0;
 833 }
 834
 835 #else
 836 #define atmel_spi_suspend       NULL
 837 #define atmel_spi_resume        NULL
 838 #endif
 839
 840
 841 static struct platform_driver atmel_spi_driver = {
 842         .driver         = {
 843                 .name   = "atmel_spi",
 844                 .owner  = THIS_MODULE,
 845         },
 846         .suspend        = atmel_spi_suspend,
 847         .resume         = atmel_spi_resume,
 848         .remove         = __exit_p(atmel_spi_remove),
 849 };
 850
 851 static int __init atmel_spi_init(void)
 852 {
 853         return platform_driver_probe(&atmel_spi_driver, atmel_spi_probe);
 854 }
 855 module_init(atmel_spi_init);
 856
 857 static void __exit atmel_spi_exit(void)
 858 {
 859         platform_driver_unregister(&atmel_spi_driver);
 860 }
 861 module_exit(atmel_spi_exit);
 862
 863 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
 864 MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
 865 MODULE_LICENSE("GPL");