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           remaining_bytes;
  55
  56         void                    *buffer;
  57         dma_addr_t              buffer_dma;
  58 };
  59
  60 #define BUFFER_SIZE             PAGE_SIZE
  61 #define INVALID_DMA_ADDRESS     0xffffffff
  62
  63 /*
  64  * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
  65  * they assume that spi slave device state will not change on deselect, so
  66  * that automagic deselection is OK.  ("NPCSx rises if no data is to be
  67  * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
  68  * controllers have CSAAT and friends.
  69  *
  70  * Since the CSAAT functionality is a bit weird on newer controllers as
  71  * well, we use GPIO to control nCSx pins on all controllers, updating
  72  * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
  73  * support active-high chipselects despite the controller's belief that
  74  * only active-low devices/systems exists.
  75  *
  76  * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
  77  * right when driven with GPIO.  ("Mode Fault does not allow more than one
  78  * Master on Chip Select 0.")  No workaround exists for that ... so for
  79  * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
  80  * and (c) will trigger that first erratum in some cases.
  81  */
  82
  83 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
  84 {
  85         unsigned gpio = (unsigned) spi->controller_data;
  86         unsigned active = spi->mode & SPI_CS_HIGH;
  87         u32 mr;
  88
  89         mr = spi_readl(as, MR);
  90         mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
  91
  92         dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
  93                         gpio, active ? " (high)" : "",
  94                         mr);
  95
  96         if (!(cpu_is_at91rm9200() && spi->chip_select == 0))
  97                 gpio_set_value(gpio, active);
  98         spi_writel(as, MR, mr);
  99 }
 100
 101 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 102 {
 103         unsigned gpio = (unsigned) spi->controller_data;
 104         unsigned active = spi->mode & SPI_CS_HIGH;
 105         u32 mr;
 106
 107         /* only deactivate *this* device; sometimes transfers to
 108          * another device may be active when this routine is called.
 109          */
 110         mr = spi_readl(as, MR);
 111         if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
 112                 mr = SPI_BFINS(PCS, 0xf, mr);
 113                 spi_writel(as, MR, mr);
 114         }
 115
 116         dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
 117                         gpio, active ? " (low)" : "",
 118                         mr);
 119
 120         if (!(cpu_is_at91rm9200() && spi->chip_select == 0))
 121                 gpio_set_value(gpio, !active);
 122 }
 123
 124 /*
 125  * Submit next transfer for DMA.
 126  * lock is held, spi irq is blocked
 127  */
 128 static void atmel_spi_next_xfer(struct spi_master *master,
 129                                 struct spi_message *msg)
 130 {
 131         struct atmel_spi        *as = spi_master_get_devdata(master);
 132         struct spi_transfer     *xfer;
 133         u32                     len;
 134         dma_addr_t              tx_dma, rx_dma;
 135
 136         xfer = as->current_transfer;
 137         if (!xfer || as->remaining_bytes == 0) {
 138                 if (xfer)
 139                         xfer = list_entry(xfer->transfer_list.next,
 140                                         struct spi_transfer, transfer_list);
 141                 else
 142                         xfer = list_entry(msg->transfers.next,
 143                                         struct spi_transfer, transfer_list);
 144                 as->remaining_bytes = xfer->len;
 145                 as->current_transfer = xfer;
 146         }
 147
 148         len = as->remaining_bytes;
 149
 150         tx_dma = xfer->tx_dma + xfer->len - len;
 151         rx_dma = xfer->rx_dma + xfer->len - len;
 152
 153         /* use scratch buffer only when rx or tx data is unspecified */
 154         if (!xfer->rx_buf) {
 155                 rx_dma = as->buffer_dma;
 156                 if (len > BUFFER_SIZE)
 157                         len = BUFFER_SIZE;
 158         }
 159         if (!xfer->tx_buf) {
 160                 tx_dma = as->buffer_dma;
 161                 if (len > BUFFER_SIZE)
 162                         len = BUFFER_SIZE;
 163                 memset(as->buffer, 0, len);
 164                 dma_sync_single_for_device(&as->pdev->dev,
 165                                 as->buffer_dma, len, DMA_TO_DEVICE);
 166         }
 167
 168         spi_writel(as, RPR, rx_dma);
 169         spi_writel(as, TPR, tx_dma);
 170
 171         as->remaining_bytes -= len;
 172         if (msg->spi->bits_per_word > 8)
 173                 len >>= 1;
 174
 175         /* REVISIT: when xfer->delay_usecs == 0, the PDC "next transfer"
 176          * mechanism might help avoid the IRQ latency between transfers
 177          * (and improve the nCS0 errata handling on at91rm9200 chips)
 178          *
 179          * We're also waiting for ENDRX before we start the next
 180          * transfer because we need to handle some difficult timing
 181          * issues otherwise. If we wait for ENDTX in one transfer and
 182          * then starts waiting for ENDRX in the next, it's difficult
 183          * to tell the difference between the ENDRX interrupt we're
 184          * actually waiting for and the ENDRX interrupt of the
 185          * previous transfer.
 186          *
 187          * It should be doable, though. Just not now...
 188          */
 189         spi_writel(as, TNCR, 0);
 190         spi_writel(as, RNCR, 0);
 191         spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
 192
 193         dev_dbg(&msg->spi->dev,
 194                 "  start xfer %p: len %u tx %p/%08x rx %p/%08x imr %03x\n",
 195                 xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 196                 xfer->rx_buf, xfer->rx_dma, spi_readl(as, IMR));
 197
 198         spi_writel(as, TCR, len);
 199         spi_writel(as, RCR, len);
 200         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 201 }
 202
 203 static void atmel_spi_next_message(struct spi_master *master)
 204 {
 205         struct atmel_spi        *as = spi_master_get_devdata(master);
 206         struct spi_message      *msg;
 207         struct spi_device       *spi;
 208
 209         BUG_ON(as->current_transfer);
 210
 211         msg = list_entry(as->queue.next, struct spi_message, queue);
 212         spi = msg->spi;
 213
 214         dev_dbg(master->dev.parent, "start message %p for %s\n",
 215                         msg, spi->dev.bus_id);
 216
 217         /* select chip if it's not still active */
 218         if (as->stay) {
 219                 if (as->stay != spi) {
 220                         cs_deactivate(as, as->stay);
 221                         cs_activate(as, spi);
 222                 }
 223                 as->stay = NULL;
 224         } else
 225                 cs_activate(as, spi);
 226
 227         atmel_spi_next_xfer(master, msg);
 228 }
 229
 230 /*
 231  * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
 232  *  - The buffer is either valid for CPU access, else NULL
 233  *  - If the buffer is valid, so is its DMA addresss
 234  *
 235  * This driver manages the dma addresss unless message->is_dma_mapped.
 236  */
 237 static int
 238 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 239 {
 240         struct device   *dev = &as->pdev->dev;
 241
 242         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 243         if (xfer->tx_buf) {
 244                 xfer->tx_dma = dma_map_single(dev,
 245                                 (void *) xfer->tx_buf, xfer->len,
 246                                 DMA_TO_DEVICE);
 247                 if (dma_mapping_error(xfer->tx_dma))
 248                         return -ENOMEM;
 249         }
 250         if (xfer->rx_buf) {
 251                 xfer->rx_dma = dma_map_single(dev,
 252                                 xfer->rx_buf, xfer->len,
 253                                 DMA_FROM_DEVICE);
 254                 if (dma_mapping_error(xfer->rx_dma)) {
 255                         if (xfer->tx_buf)
 256                                 dma_unmap_single(dev,
 257                                                 xfer->tx_dma, xfer->len,
 258                                                 DMA_TO_DEVICE);
 259                         return -ENOMEM;
 260                 }
 261         }
 262         return 0;
 263 }
 264
 265 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
 266                                      struct spi_transfer *xfer)
 267 {
 268         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
 269                 dma_unmap_single(master->dev.parent, xfer->tx_dma,
 270                                  xfer->len, DMA_TO_DEVICE);
 271         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
 272                 dma_unmap_single(master->dev.parent, xfer->rx_dma,
 273                                  xfer->len, DMA_FROM_DEVICE);
 274 }
 275
 276 static void
 277 atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
 278                 struct spi_message *msg, int status, int stay)
 279 {
 280         if (!stay || status < 0)
 281                 cs_deactivate(as, msg->spi);
 282         else
 283                 as->stay = msg->spi;
 284
 285         list_del(&msg->queue);
 286         msg->status = status;
 287
 288         dev_dbg(master->dev.parent,
 289                 "xfer complete: %u bytes transferred\n",
 290                 msg->actual_length);
 291
 292         spin_unlock(&as->lock);
 293         msg->complete(msg->context);
 294         spin_lock(&as->lock);
 295
 296         as->current_transfer = NULL;
 297
 298         /* continue if needed */
 299         if (list_empty(&as->queue) || as->stopping)
 300                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 301         else
 302                 atmel_spi_next_message(master);
 303 }
 304
 305 static irqreturn_t
 306 atmel_spi_interrupt(int irq, void *dev_id)
 307 {
 308         struct spi_master       *master = dev_id;
 309         struct atmel_spi        *as = spi_master_get_devdata(master);
 310         struct spi_message      *msg;
 311         struct spi_transfer     *xfer;
 312         u32                     status, pending, imr;
 313         int                     ret = IRQ_NONE;
 314
 315         spin_lock(&as->lock);
 316
 317         xfer = as->current_transfer;
 318         msg = list_entry(as->queue.next, struct spi_message, queue);
 319
 320         imr = spi_readl(as, IMR);
 321         status = spi_readl(as, SR);
 322         pending = status & imr;
 323
 324         if (pending & SPI_BIT(OVRES)) {
 325                 int timeout;
 326
 327                 ret = IRQ_HANDLED;
 328
 329                 spi_writel(as, IDR, (SPI_BIT(ENDTX) | SPI_BIT(ENDRX)
 330                                      | SPI_BIT(OVRES)));
 331
 332                 /*
 333                  * When we get an overrun, we disregard the current
 334                  * transfer. Data will not be copied back from any
 335                  * bounce buffer and msg->actual_len will not be
 336                  * updated with the last xfer.
 337                  *
 338                  * We will also not process any remaning transfers in
 339                  * the message.
 340                  *
 341                  * First, stop the transfer and unmap the DMA buffers.
 342                  */
 343                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 344                 if (!msg->is_dma_mapped)
 345                         atmel_spi_dma_unmap_xfer(master, xfer);
 346
 347                 /* REVISIT: udelay in irq is unfriendly */
 348                 if (xfer->delay_usecs)
 349                         udelay(xfer->delay_usecs);
 350
 351                 dev_warn(master->dev.parent, "fifo overrun (%u/%u remaining)\n",
 352                          spi_readl(as, TCR), spi_readl(as, RCR));
 353
 354                 /*
 355                  * Clean up DMA registers and make sure the data
 356                  * registers are empty.
 357                  */
 358                 spi_writel(as, RNCR, 0);
 359                 spi_writel(as, TNCR, 0);
 360                 spi_writel(as, RCR, 0);
 361                 spi_writel(as, TCR, 0);
 362                 for (timeout = 1000; timeout; timeout--)
 363                         if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
 364                                 break;
 365                 if (!timeout)
 366                         dev_warn(master->dev.parent,
 367                                  "timeout waiting for TXEMPTY");
 368                 while (spi_readl(as, SR) & SPI_BIT(RDRF))
 369                         spi_readl(as, RDR);
 370
 371                 /* Clear any overrun happening while cleaning up */
 372                 spi_readl(as, SR);
 373
 374                 atmel_spi_msg_done(master, as, msg, -EIO, 0);
 375         } else if (pending & SPI_BIT(ENDRX)) {
 376                 ret = IRQ_HANDLED;
 377
 378                 spi_writel(as, IDR, pending);
 379
 380                 if (as->remaining_bytes == 0) {
 381                         msg->actual_length += xfer->len;
 382
 383                         if (!msg->is_dma_mapped)
 384                                 atmel_spi_dma_unmap_xfer(master, xfer);
 385
 386                         /* REVISIT: udelay in irq is unfriendly */
 387                         if (xfer->delay_usecs)
 388                                 udelay(xfer->delay_usecs);
 389
 390                         if (msg->transfers.prev == &xfer->transfer_list) {
 391                                 /* report completed message */
 392                                 atmel_spi_msg_done(master, as, msg, 0,
 393                                                 xfer->cs_change);
 394                         } else {
 395                                 if (xfer->cs_change) {
 396                                         cs_deactivate(as, msg->spi);
 397                                         udelay(1);
 398                                         cs_activate(as, msg->spi);
 399                                 }
 400
 401                                 /*
 402                                  * Not done yet. Submit the next transfer.
 403                                  *
 404                                  * FIXME handle protocol options for xfer
 405                                  */
 406                                 atmel_spi_next_xfer(master, msg);
 407                         }
 408                 } else {
 409                         /*
 410                          * Keep going, we still have data to send in
 411                          * the current transfer.
 412                          */
 413                         atmel_spi_next_xfer(master, msg);
 414                 }
 415         }
 416
 417         spin_unlock(&as->lock);
 418
 419         return ret;
 420 }
 421
 422 /* the spi->mode bits understood by this driver: */
 423 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 424
 425 static int atmel_spi_setup(struct spi_device *spi)
 426 {
 427         struct atmel_spi        *as;
 428         u32                     scbr, csr;
 429         unsigned int            bits = spi->bits_per_word;
 430         unsigned long           bus_hz, sck_hz;
 431         unsigned int            npcs_pin;
 432         int                     ret;
 433
 434         as = spi_master_get_devdata(spi->master);
 435
 436         if (as->stopping)
 437                 return -ESHUTDOWN;
 438
 439         if (spi->chip_select > spi->master->num_chipselect) {
 440                 dev_dbg(&spi->dev,
 441                                 "setup: invalid chipselect %u (%u defined)\n",
 442                                 spi->chip_select, spi->master->num_chipselect);
 443                 return -EINVAL;
 444         }
 445
 446         if (bits == 0)
 447                 bits = 8;
 448         if (bits < 8 || bits > 16) {
 449                 dev_dbg(&spi->dev,
 450                                 "setup: invalid bits_per_word %u (8 to 16)\n",
 451                                 bits);
 452                 return -EINVAL;
 453         }
 454
 455         if (spi->mode & ~MODEBITS) {
 456                 dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
 457                         spi->mode & ~MODEBITS);
 458                 return -EINVAL;
 459         }
 460
 461         /* see notes above re chipselect */
 462         if (cpu_is_at91rm9200()
 463                         && spi->chip_select == 0
 464                         && (spi->mode & SPI_CS_HIGH)) {
 465                 dev_dbg(&spi->dev, "setup: can't be active-high\n");
 466                 return -EINVAL;
 467         }
 468
 469         /* speed zero convention is used by some upper layers */
 470         bus_hz = clk_get_rate(as->clk);
 471         if (spi->max_speed_hz) {
 472                 /* assume div32/fdiv/mbz == 0 */
 473                 if (!as->new_1)
 474                         bus_hz /= 2;
 475                 scbr = ((bus_hz + spi->max_speed_hz - 1)
 476                         / spi->max_speed_hz);
 477                 if (scbr >= (1 << SPI_SCBR_SIZE)) {
 478                         dev_dbg(&spi->dev,
 479                                 "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
 480                                 spi->max_speed_hz, scbr, bus_hz/255);
 481                         return -EINVAL;
 482                 }
 483         } else
 484                 scbr = 0xff;
 485         sck_hz = bus_hz / scbr;
 486
 487         csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
 488         if (spi->mode & SPI_CPOL)
 489                 csr |= SPI_BIT(CPOL);
 490         if (!(spi->mode & SPI_CPHA))
 491                 csr |= SPI_BIT(NCPHA);
 492
 493         /* TODO: DLYBS and DLYBCT */
 494         csr |= SPI_BF(DLYBS, 10);
 495         csr |= SPI_BF(DLYBCT, 10);
 496
 497         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
 498         npcs_pin = (unsigned int)spi->controller_data;
 499         if (!spi->controller_state) {
 500                 ret = gpio_request(npcs_pin, spi->dev.bus_id);
 501                 if (ret)
 502                         return ret;
 503                 spi->controller_state = (void *)npcs_pin;
 504                 gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
 505         } else {
 506                 unsigned long           flags;
 507
 508                 spin_lock_irqsave(&as->lock, flags);
 509                 if (as->stay == spi)
 510                         as->stay = NULL;
 511                 cs_deactivate(as, spi);
 512                 spin_unlock_irqrestore(&as->lock, flags);
 513         }
 514
 515         dev_dbg(&spi->dev,
 516                 "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
 517                 sck_hz, bits, spi->mode, spi->chip_select, csr);
 518
 519         spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 520
 521         return 0;
 522 }
 523
 524 static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
 525 {
 526         struct atmel_spi        *as;
 527         struct spi_transfer     *xfer;
 528         unsigned long           flags;
 529         struct device           *controller = spi->master->dev.parent;
 530
 531         as = spi_master_get_devdata(spi->master);
 532
 533         dev_dbg(controller, "new message %p submitted for %s\n",
 534                         msg, spi->dev.bus_id);
 535
 536         if (unlikely(list_empty(&msg->transfers)
 537                         || !spi->max_speed_hz))
 538                 return -EINVAL;
 539
 540         if (as->stopping)
 541                 return -ESHUTDOWN;
 542
 543         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 544                 if (!(xfer->tx_buf || xfer->rx_buf)) {
 545                         dev_dbg(&spi->dev, "missing rx or tx buf\n");
 546                         return -EINVAL;
 547                 }
 548
 549                 /* FIXME implement these protocol options!! */
 550                 if (xfer->bits_per_word || xfer->speed_hz) {
 551                         dev_dbg(&spi->dev, "no protocol options yet\n");
 552                         return -ENOPROTOOPT;
 553                 }
 554
 555                 /*
 556                  * DMA map early, for performance (empties dcache ASAP) and
 557                  * better fault reporting.  This is a DMA-only driver.
 558                  *
 559                  * NOTE that if dma_unmap_single() ever starts to do work on
 560                  * platforms supported by this driver, we would need to clean
 561                  * up mappings for previously-mapped transfers.
 562                  */
 563                 if (!msg->is_dma_mapped) {
 564                         if (atmel_spi_dma_map_xfer(as, xfer) < 0)
 565                                 return -ENOMEM;
 566                 }
 567         }
 568
 569 #ifdef VERBOSE
 570         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 571                 dev_dbg(controller,
 572                         "  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 573                         xfer, xfer->len,
 574                         xfer->tx_buf, xfer->tx_dma,
 575                         xfer->rx_buf, xfer->rx_dma);
 576         }
 577 #endif
 578
 579         msg->status = -EINPROGRESS;
 580         msg->actual_length = 0;
 581
 582         spin_lock_irqsave(&as->lock, flags);
 583         list_add_tail(&msg->queue, &as->queue);
 584         if (!as->current_transfer)
 585                 atmel_spi_next_message(spi->master);
 586         spin_unlock_irqrestore(&as->lock, flags);
 587
 588         return 0;
 589 }
 590
 591 static void atmel_spi_cleanup(struct spi_device *spi)
 592 {
 593         struct atmel_spi        *as = spi_master_get_devdata(spi->master);
 594         unsigned                gpio = (unsigned) spi->controller_data;
 595         unsigned long           flags;
 596
 597         if (!spi->controller_state)
 598                 return;
 599
 600         spin_lock_irqsave(&as->lock, flags);
 601         if (as->stay == spi) {
 602                 as->stay = NULL;
 603                 cs_deactivate(as, spi);
 604         }
 605         spin_unlock_irqrestore(&as->lock, flags);
 606
 607         gpio_free(gpio);
 608 }
 609
 610 /*-------------------------------------------------------------------------*/
 611
 612 static int __init atmel_spi_probe(struct platform_device *pdev)
 613 {
 614         struct resource         *regs;
 615         int                     irq;
 616         struct clk              *clk;
 617         int                     ret;
 618         struct spi_master       *master;
 619         struct atmel_spi        *as;
 620
 621         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 622         if (!regs)
 623                 return -ENXIO;
 624
 625         irq = platform_get_irq(pdev, 0);
 626         if (irq < 0)
 627                 return irq;
 628
 629         clk = clk_get(&pdev->dev, "spi_clk");
 630         if (IS_ERR(clk))
 631                 return PTR_ERR(clk);
 632
 633         /* setup spi core then atmel-specific driver state */
 634         ret = -ENOMEM;
 635         master = spi_alloc_master(&pdev->dev, sizeof *as);
 636         if (!master)
 637                 goto out_free;
 638
 639         master->bus_num = pdev->id;
 640         master->num_chipselect = 4;
 641         master->setup = atmel_spi_setup;
 642         master->transfer = atmel_spi_transfer;
 643         master->cleanup = atmel_spi_cleanup;
 644         platform_set_drvdata(pdev, master);
 645
 646         as = spi_master_get_devdata(master);
 647
 648         /*
 649          * Scratch buffer is used for throwaway rx and tx data.
 650          * It's coherent to minimize dcache pollution.
 651          */
 652         as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
 653                                         &as->buffer_dma, GFP_KERNEL);
 654         if (!as->buffer)
 655                 goto out_free;
 656
 657         spin_lock_init(&as->lock);
 658         INIT_LIST_HEAD(&as->queue);
 659         as->pdev = pdev;
 660         as->regs = ioremap(regs->start, (regs->end - regs->start) + 1);
 661         if (!as->regs)
 662                 goto out_free_buffer;
 663         as->irq = irq;
 664         as->clk = clk;
 665         if (!cpu_is_at91rm9200())
 666                 as->new_1 = 1;
 667
 668         ret = request_irq(irq, atmel_spi_interrupt, 0,
 669                         pdev->dev.bus_id, master);
 670         if (ret)
 671                 goto out_unmap_regs;
 672
 673         /* Initialize the hardware */
 674         clk_enable(clk);
 675         spi_writel(as, CR, SPI_BIT(SWRST));
 676         spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
 677         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 678         spi_writel(as, CR, SPI_BIT(SPIEN));
 679
 680         /* go! */
 681         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
 682                         (unsigned long)regs->start, irq);
 683
 684         ret = spi_register_master(master);
 685         if (ret)
 686                 goto out_reset_hw;
 687
 688         return 0;
 689
 690 out_reset_hw:
 691         spi_writel(as, CR, SPI_BIT(SWRST));
 692         clk_disable(clk);
 693         free_irq(irq, master);
 694 out_unmap_regs:
 695         iounmap(as->regs);
 696 out_free_buffer:
 697         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 698                         as->buffer_dma);
 699 out_free:
 700         clk_put(clk);
 701         spi_master_put(master);
 702         return ret;
 703 }
 704
 705 static int __exit atmel_spi_remove(struct platform_device *pdev)
 706 {
 707         struct spi_master       *master = platform_get_drvdata(pdev);
 708         struct atmel_spi        *as = spi_master_get_devdata(master);
 709         struct spi_message      *msg;
 710
 711         /* reset the hardware and block queue progress */
 712         spin_lock_irq(&as->lock);
 713         as->stopping = 1;
 714         spi_writel(as, CR, SPI_BIT(SWRST));
 715         spi_readl(as, SR);
 716         spin_unlock_irq(&as->lock);
 717
 718         /* Terminate remaining queued transfers */
 719         list_for_each_entry(msg, &as->queue, queue) {
 720                 /* REVISIT unmapping the dma is a NOP on ARM and AVR32
 721                  * but we shouldn't depend on that...
 722                  */
 723                 msg->status = -ESHUTDOWN;
 724                 msg->complete(msg->context);
 725         }
 726
 727         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 728                         as->buffer_dma);
 729
 730         clk_disable(as->clk);
 731         clk_put(as->clk);
 732         free_irq(as->irq, master);
 733         iounmap(as->regs);
 734
 735         spi_unregister_master(master);
 736
 737         return 0;
 738 }
 739
 740 #ifdef  CONFIG_PM
 741
 742 static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
 743 {
 744         struct spi_master       *master = platform_get_drvdata(pdev);
 745         struct atmel_spi        *as = spi_master_get_devdata(master);
 746
 747         clk_disable(as->clk);
 748         return 0;
 749 }
 750
 751 static int atmel_spi_resume(struct platform_device *pdev)
 752 {
 753         struct spi_master       *master = platform_get_drvdata(pdev);
 754         struct atmel_spi        *as = spi_master_get_devdata(master);
 755
 756         clk_enable(as->clk);
 757         return 0;
 758 }
 759
 760 #else
 761 #define atmel_spi_suspend       NULL
 762 #define atmel_spi_resume        NULL
 763 #endif
 764
 765
 766 static struct platform_driver atmel_spi_driver = {
 767         .driver         = {
 768                 .name   = "atmel_spi",
 769                 .owner  = THIS_MODULE,
 770         },
 771         .suspend        = atmel_spi_suspend,
 772         .resume         = atmel_spi_resume,
 773         .remove         = __exit_p(atmel_spi_remove),
 774 };
 775
 776 static int __init atmel_spi_init(void)
 777 {
 778         return platform_driver_probe(&atmel_spi_driver, atmel_spi_probe);
 779 }
 780 module_init(atmel_spi_init);
 781
 782 static void __exit atmel_spi_exit(void)
 783 {
 784         platform_driver_unregister(&atmel_spi_driver);
 785 }
 786 module_exit(atmel_spi_exit);
 787
 788 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
 789 MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
 790 MODULE_LICENSE("GPL");