Pileus Git - ~andy/linux/blob - drivers/spi/spi-atmel.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/dmaengine.h>
  19 #include <linux/err.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/spi/spi.h>
  22 #include <linux/slab.h>
  23 #include <linux/platform_data/atmel.h>
  24 #include <linux/platform_data/dma-atmel.h>
  25 #include <linux/of.h>
  26
  27 #include <linux/io.h>
  28 #include <linux/gpio.h>
  29
  30 /* SPI register offsets */
  31 #define SPI_CR                                  0x0000
  32 #define SPI_MR                                  0x0004
  33 #define SPI_RDR                                 0x0008
  34 #define SPI_TDR                                 0x000c
  35 #define SPI_SR                                  0x0010
  36 #define SPI_IER                                 0x0014
  37 #define SPI_IDR                                 0x0018
  38 #define SPI_IMR                                 0x001c
  39 #define SPI_CSR0                                0x0030
  40 #define SPI_CSR1                                0x0034
  41 #define SPI_CSR2                                0x0038
  42 #define SPI_CSR3                                0x003c
  43 #define SPI_VERSION                             0x00fc
  44 #define SPI_RPR                                 0x0100
  45 #define SPI_RCR                                 0x0104
  46 #define SPI_TPR                                 0x0108
  47 #define SPI_TCR                                 0x010c
  48 #define SPI_RNPR                                0x0110
  49 #define SPI_RNCR                                0x0114
  50 #define SPI_TNPR                                0x0118
  51 #define SPI_TNCR                                0x011c
  52 #define SPI_PTCR                                0x0120
  53 #define SPI_PTSR                                0x0124
  54
  55 /* Bitfields in CR */
  56 #define SPI_SPIEN_OFFSET                        0
  57 #define SPI_SPIEN_SIZE                          1
  58 #define SPI_SPIDIS_OFFSET                       1
  59 #define SPI_SPIDIS_SIZE                         1
  60 #define SPI_SWRST_OFFSET                        7
  61 #define SPI_SWRST_SIZE                          1
  62 #define SPI_LASTXFER_OFFSET                     24
  63 #define SPI_LASTXFER_SIZE                       1
  64
  65 /* Bitfields in MR */
  66 #define SPI_MSTR_OFFSET                         0
  67 #define SPI_MSTR_SIZE                           1
  68 #define SPI_PS_OFFSET                           1
  69 #define SPI_PS_SIZE                             1
  70 #define SPI_PCSDEC_OFFSET                       2
  71 #define SPI_PCSDEC_SIZE                         1
  72 #define SPI_FDIV_OFFSET                         3
  73 #define SPI_FDIV_SIZE                           1
  74 #define SPI_MODFDIS_OFFSET                      4
  75 #define SPI_MODFDIS_SIZE                        1
  76 #define SPI_WDRBT_OFFSET                        5
  77 #define SPI_WDRBT_SIZE                          1
  78 #define SPI_LLB_OFFSET                          7
  79 #define SPI_LLB_SIZE                            1
  80 #define SPI_PCS_OFFSET                          16
  81 #define SPI_PCS_SIZE                            4
  82 #define SPI_DLYBCS_OFFSET                       24
  83 #define SPI_DLYBCS_SIZE                         8
  84
  85 /* Bitfields in RDR */
  86 #define SPI_RD_OFFSET                           0
  87 #define SPI_RD_SIZE                             16
  88
  89 /* Bitfields in TDR */
  90 #define SPI_TD_OFFSET                           0
  91 #define SPI_TD_SIZE                             16
  92
  93 /* Bitfields in SR */
  94 #define SPI_RDRF_OFFSET                         0
  95 #define SPI_RDRF_SIZE                           1
  96 #define SPI_TDRE_OFFSET                         1
  97 #define SPI_TDRE_SIZE                           1
  98 #define SPI_MODF_OFFSET                         2
  99 #define SPI_MODF_SIZE                           1
 100 #define SPI_OVRES_OFFSET                        3
 101 #define SPI_OVRES_SIZE                          1
 102 #define SPI_ENDRX_OFFSET                        4
 103 #define SPI_ENDRX_SIZE                          1
 104 #define SPI_ENDTX_OFFSET                        5
 105 #define SPI_ENDTX_SIZE                          1
 106 #define SPI_RXBUFF_OFFSET                       6
 107 #define SPI_RXBUFF_SIZE                         1
 108 #define SPI_TXBUFE_OFFSET                       7
 109 #define SPI_TXBUFE_SIZE                         1
 110 #define SPI_NSSR_OFFSET                         8
 111 #define SPI_NSSR_SIZE                           1
 112 #define SPI_TXEMPTY_OFFSET                      9
 113 #define SPI_TXEMPTY_SIZE                        1
 114 #define SPI_SPIENS_OFFSET                       16
 115 #define SPI_SPIENS_SIZE                         1
 116
 117 /* Bitfields in CSR0 */
 118 #define SPI_CPOL_OFFSET                         0
 119 #define SPI_CPOL_SIZE                           1
 120 #define SPI_NCPHA_OFFSET                        1
 121 #define SPI_NCPHA_SIZE                          1
 122 #define SPI_CSAAT_OFFSET                        3
 123 #define SPI_CSAAT_SIZE                          1
 124 #define SPI_BITS_OFFSET                         4
 125 #define SPI_BITS_SIZE                           4
 126 #define SPI_SCBR_OFFSET                         8
 127 #define SPI_SCBR_SIZE                           8
 128 #define SPI_DLYBS_OFFSET                        16
 129 #define SPI_DLYBS_SIZE                          8
 130 #define SPI_DLYBCT_OFFSET                       24
 131 #define SPI_DLYBCT_SIZE                         8
 132
 133 /* Bitfields in RCR */
 134 #define SPI_RXCTR_OFFSET                        0
 135 #define SPI_RXCTR_SIZE                          16
 136
 137 /* Bitfields in TCR */
 138 #define SPI_TXCTR_OFFSET                        0
 139 #define SPI_TXCTR_SIZE                          16
 140
 141 /* Bitfields in RNCR */
 142 #define SPI_RXNCR_OFFSET                        0
 143 #define SPI_RXNCR_SIZE                          16
 144
 145 /* Bitfields in TNCR */
 146 #define SPI_TXNCR_OFFSET                        0
 147 #define SPI_TXNCR_SIZE                          16
 148
 149 /* Bitfields in PTCR */
 150 #define SPI_RXTEN_OFFSET                        0
 151 #define SPI_RXTEN_SIZE                          1
 152 #define SPI_RXTDIS_OFFSET                       1
 153 #define SPI_RXTDIS_SIZE                         1
 154 #define SPI_TXTEN_OFFSET                        8
 155 #define SPI_TXTEN_SIZE                          1
 156 #define SPI_TXTDIS_OFFSET                       9
 157 #define SPI_TXTDIS_SIZE                         1
 158
 159 /* Constants for BITS */
 160 #define SPI_BITS_8_BPT                          0
 161 #define SPI_BITS_9_BPT                          1
 162 #define SPI_BITS_10_BPT                         2
 163 #define SPI_BITS_11_BPT                         3
 164 #define SPI_BITS_12_BPT                         4
 165 #define SPI_BITS_13_BPT                         5
 166 #define SPI_BITS_14_BPT                         6
 167 #define SPI_BITS_15_BPT                         7
 168 #define SPI_BITS_16_BPT                         8
 169
 170 /* Bit manipulation macros */
 171 #define SPI_BIT(name) \
 172         (1 << SPI_##name##_OFFSET)
 173 #define SPI_BF(name,value) \
 174         (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
 175 #define SPI_BFEXT(name,value) \
 176         (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
 177 #define SPI_BFINS(name,value,old) \
 178         ( ((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
 179           | SPI_BF(name,value))
 180
 181 /* Register access macros */
 182 #define spi_readl(port,reg) \
 183         __raw_readl((port)->regs + SPI_##reg)
 184 #define spi_writel(port,reg,value) \
 185         __raw_writel((value), (port)->regs + SPI_##reg)
 186
 187 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
 188  * cache operations; better heuristics consider wordsize and bitrate.
 189  */
 190 #define DMA_MIN_BYTES   16
 191
 192 struct atmel_spi_dma {
 193         struct dma_chan                 *chan_rx;
 194         struct dma_chan                 *chan_tx;
 195         struct scatterlist              sgrx;
 196         struct scatterlist              sgtx;
 197         struct dma_async_tx_descriptor  *data_desc_rx;
 198         struct dma_async_tx_descriptor  *data_desc_tx;
 199
 200         struct at_dma_slave     dma_slave;
 201 };
 202
 203 struct atmel_spi_caps {
 204         bool    is_spi2;
 205         bool    has_wdrbt;
 206         bool    has_dma_support;
 207 };
 208
 209 /*
 210  * The core SPI transfer engine just talks to a register bank to set up
 211  * DMA transfers; transfer queue progress is driven by IRQs.  The clock
 212  * framework provides the base clock, subdivided for each spi_device.
 213  */
 214 struct atmel_spi {
 215         spinlock_t              lock;
 216         unsigned long           flags;
 217
 218         phys_addr_t             phybase;
 219         void __iomem            *regs;
 220         int                     irq;
 221         struct clk              *clk;
 222         struct platform_device  *pdev;
 223         struct spi_device       *stay;
 224
 225         u8                      stopping;
 226         struct list_head        queue;
 227         struct tasklet_struct   tasklet;
 228         struct spi_transfer     *current_transfer;
 229         unsigned long           current_remaining_bytes;
 230         struct spi_transfer     *next_transfer;
 231         unsigned long           next_remaining_bytes;
 232         int                     done_status;
 233
 234         /* scratch buffer */
 235         void                    *buffer;
 236         dma_addr_t              buffer_dma;
 237
 238         struct atmel_spi_caps   caps;
 239
 240         bool                    use_dma;
 241         bool                    use_pdc;
 242         /* dmaengine data */
 243         struct atmel_spi_dma    dma;
 244 };
 245
 246 /* Controller-specific per-slave state */
 247 struct atmel_spi_device {
 248         unsigned int            npcs_pin;
 249         u32                     csr;
 250 };
 251
 252 #define BUFFER_SIZE             PAGE_SIZE
 253 #define INVALID_DMA_ADDRESS     0xffffffff
 254
 255 /*
 256  * Version 2 of the SPI controller has
 257  *  - CR.LASTXFER
 258  *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
 259  *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
 260  *  - SPI_CSRx.CSAAT
 261  *  - SPI_CSRx.SBCR allows faster clocking
 262  */
 263 static bool atmel_spi_is_v2(struct atmel_spi *as)
 264 {
 265         return as->caps.is_spi2;
 266 }
 267
 268 /*
 269  * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
 270  * they assume that spi slave device state will not change on deselect, so
 271  * that automagic deselection is OK.  ("NPCSx rises if no data is to be
 272  * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
 273  * controllers have CSAAT and friends.
 274  *
 275  * Since the CSAAT functionality is a bit weird on newer controllers as
 276  * well, we use GPIO to control nCSx pins on all controllers, updating
 277  * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
 278  * support active-high chipselects despite the controller's belief that
 279  * only active-low devices/systems exists.
 280  *
 281  * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
 282  * right when driven with GPIO.  ("Mode Fault does not allow more than one
 283  * Master on Chip Select 0.")  No workaround exists for that ... so for
 284  * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
 285  * and (c) will trigger that first erratum in some cases.
 286  */
 287
 288 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 289 {
 290         struct atmel_spi_device *asd = spi->controller_state;
 291         unsigned active = spi->mode & SPI_CS_HIGH;
 292         u32 mr;
 293
 294         if (atmel_spi_is_v2(as)) {
 295                 spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
 296                 /* For the low SPI version, there is a issue that PDC transfer
 297                  * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
 298                  */
 299                 spi_writel(as, CSR0, asd->csr);
 300                 if (as->caps.has_wdrbt) {
 301                         spi_writel(as, MR,
 302                                         SPI_BF(PCS, ~(0x01 << spi->chip_select))
 303                                         | SPI_BIT(WDRBT)
 304                                         | SPI_BIT(MODFDIS)
 305                                         | SPI_BIT(MSTR));
 306                 } else {
 307                         spi_writel(as, MR,
 308                                         SPI_BF(PCS, ~(0x01 << spi->chip_select))
 309                                         | SPI_BIT(MODFDIS)
 310                                         | SPI_BIT(MSTR));
 311                 }
 312
 313                 mr = spi_readl(as, MR);
 314                 gpio_set_value(asd->npcs_pin, active);
 315         } else {
 316                 u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
 317                 int i;
 318                 u32 csr;
 319
 320                 /* Make sure clock polarity is correct */
 321                 for (i = 0; i < spi->master->num_chipselect; i++) {
 322                         csr = spi_readl(as, CSR0 + 4 * i);
 323                         if ((csr ^ cpol) & SPI_BIT(CPOL))
 324                                 spi_writel(as, CSR0 + 4 * i,
 325                                                 csr ^ SPI_BIT(CPOL));
 326                 }
 327
 328                 mr = spi_readl(as, MR);
 329                 mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
 330                 if (spi->chip_select != 0)
 331                         gpio_set_value(asd->npcs_pin, active);
 332                 spi_writel(as, MR, mr);
 333         }
 334
 335         dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
 336                         asd->npcs_pin, active ? " (high)" : "",
 337                         mr);
 338 }
 339
 340 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 341 {
 342         struct atmel_spi_device *asd = spi->controller_state;
 343         unsigned active = spi->mode & SPI_CS_HIGH;
 344         u32 mr;
 345
 346         /* only deactivate *this* device; sometimes transfers to
 347          * another device may be active when this routine is called.
 348          */
 349         mr = spi_readl(as, MR);
 350         if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
 351                 mr = SPI_BFINS(PCS, 0xf, mr);
 352                 spi_writel(as, MR, mr);
 353         }
 354
 355         dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
 356                         asd->npcs_pin, active ? " (low)" : "",
 357                         mr);
 358
 359         if (atmel_spi_is_v2(as) || spi->chip_select != 0)
 360                 gpio_set_value(asd->npcs_pin, !active);
 361 }
 362
 363 static void atmel_spi_lock(struct atmel_spi *as)
 364 {
 365         spin_lock_irqsave(&as->lock, as->flags);
 366 }
 367
 368 static void atmel_spi_unlock(struct atmel_spi *as)
 369 {
 370         spin_unlock_irqrestore(&as->lock, as->flags);
 371 }
 372
 373 static inline bool atmel_spi_use_dma(struct atmel_spi *as,
 374                                 struct spi_transfer *xfer)
 375 {
 376         return as->use_dma && xfer->len >= DMA_MIN_BYTES;
 377 }
 378
 379 static inline int atmel_spi_xfer_is_last(struct spi_message *msg,
 380                                         struct spi_transfer *xfer)
 381 {
 382         return msg->transfers.prev == &xfer->transfer_list;
 383 }
 384
 385 static inline int atmel_spi_xfer_can_be_chained(struct spi_transfer *xfer)
 386 {
 387         return xfer->delay_usecs == 0 && !xfer->cs_change;
 388 }
 389
 390 static int atmel_spi_dma_slave_config(struct atmel_spi *as,
 391                                 struct dma_slave_config *slave_config,
 392                                 u8 bits_per_word)
 393 {
 394         int err = 0;
 395
 396         if (bits_per_word > 8) {
 397                 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 398                 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 399         } else {
 400                 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 401                 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 402         }
 403
 404         slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
 405         slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR;
 406         slave_config->src_maxburst = 1;
 407         slave_config->dst_maxburst = 1;
 408         slave_config->device_fc = false;
 409
 410         slave_config->direction = DMA_MEM_TO_DEV;
 411         if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) {
 412                 dev_err(&as->pdev->dev,
 413                         "failed to configure tx dma channel\n");
 414                 err = -EINVAL;
 415         }
 416
 417         slave_config->direction = DMA_DEV_TO_MEM;
 418         if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) {
 419                 dev_err(&as->pdev->dev,
 420                         "failed to configure rx dma channel\n");
 421                 err = -EINVAL;
 422         }
 423
 424         return err;
 425 }
 426
 427 static bool filter(struct dma_chan *chan, void *slave)
 428 {
 429         struct  at_dma_slave *sl = slave;
 430
 431         if (sl->dma_dev == chan->device->dev) {
 432                 chan->private = sl;
 433                 return true;
 434         } else {
 435                 return false;
 436         }
 437 }
 438
 439 static int atmel_spi_configure_dma(struct atmel_spi *as)
 440 {
 441         struct at_dma_slave *sdata = &as->dma.dma_slave;
 442         struct dma_slave_config slave_config;
 443         int err;
 444
 445         if (sdata && sdata->dma_dev) {
 446                 dma_cap_mask_t mask;
 447
 448                 /* Try to grab two DMA channels */
 449                 dma_cap_zero(mask);
 450                 dma_cap_set(DMA_SLAVE, mask);
 451                 as->dma.chan_tx = dma_request_channel(mask, filter, sdata);
 452                 if (as->dma.chan_tx)
 453                         as->dma.chan_rx =
 454                                 dma_request_channel(mask, filter, sdata);
 455         }
 456         if (!as->dma.chan_rx || !as->dma.chan_tx) {
 457                 dev_err(&as->pdev->dev,
 458                         "DMA channel not available, SPI unable to use DMA\n");
 459                 err = -EBUSY;
 460                 goto error;
 461         }
 462
 463         err = atmel_spi_dma_slave_config(as, &slave_config, 8);
 464         if (err)
 465                 goto error;
 466
 467         dev_info(&as->pdev->dev,
 468                         "Using %s (tx) and %s (rx) for DMA transfers\n",
 469                         dma_chan_name(as->dma.chan_tx),
 470                         dma_chan_name(as->dma.chan_rx));
 471         return 0;
 472 error:
 473         if (as->dma.chan_rx)
 474                 dma_release_channel(as->dma.chan_rx);
 475         if (as->dma.chan_tx)
 476                 dma_release_channel(as->dma.chan_tx);
 477         return err;
 478 }
 479
 480 static void atmel_spi_stop_dma(struct atmel_spi *as)
 481 {
 482         if (as->dma.chan_rx)
 483                 as->dma.chan_rx->device->device_control(as->dma.chan_rx,
 484                                                         DMA_TERMINATE_ALL, 0);
 485         if (as->dma.chan_tx)
 486                 as->dma.chan_tx->device->device_control(as->dma.chan_tx,
 487                                                         DMA_TERMINATE_ALL, 0);
 488 }
 489
 490 static void atmel_spi_release_dma(struct atmel_spi *as)
 491 {
 492         if (as->dma.chan_rx)
 493                 dma_release_channel(as->dma.chan_rx);
 494         if (as->dma.chan_tx)
 495                 dma_release_channel(as->dma.chan_tx);
 496 }
 497
 498 /* This function is called by the DMA driver from tasklet context */
 499 static void dma_callback(void *data)
 500 {
 501         struct spi_master       *master = data;
 502         struct atmel_spi        *as = spi_master_get_devdata(master);
 503
 504         /* trigger SPI tasklet */
 505         tasklet_schedule(&as->tasklet);
 506 }
 507
 508 /*
 509  * Next transfer using PIO.
 510  * lock is held, spi tasklet is blocked
 511  */
 512 static void atmel_spi_next_xfer_pio(struct spi_master *master,
 513                                 struct spi_transfer *xfer)
 514 {
 515         struct atmel_spi        *as = spi_master_get_devdata(master);
 516
 517         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
 518
 519         as->current_remaining_bytes = xfer->len;
 520
 521         /* Make sure data is not remaining in RDR */
 522         spi_readl(as, RDR);
 523         while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
 524                 spi_readl(as, RDR);
 525                 cpu_relax();
 526         }
 527
 528         if (xfer->tx_buf)
 529                 if (xfer->bits_per_word > 8)
 530                         spi_writel(as, TDR, *(u16 *)(xfer->tx_buf));
 531                 else
 532                         spi_writel(as, TDR, *(u8 *)(xfer->tx_buf));
 533         else
 534                 spi_writel(as, TDR, 0);
 535
 536         dev_dbg(master->dev.parent,
 537                 "  start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
 538                 xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
 539                 xfer->bits_per_word);
 540
 541         /* Enable relevant interrupts */
 542         spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES));
 543 }
 544
 545 /*
 546  * Submit next transfer for DMA.
 547  * lock is held, spi tasklet is blocked
 548  */
 549 static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
 550                                 struct spi_transfer *xfer,
 551                                 u32 *plen)
 552 {
 553         struct atmel_spi        *as = spi_master_get_devdata(master);
 554         struct dma_chan         *rxchan = as->dma.chan_rx;
 555         struct dma_chan         *txchan = as->dma.chan_tx;
 556         struct dma_async_tx_descriptor *rxdesc;
 557         struct dma_async_tx_descriptor *txdesc;
 558         struct dma_slave_config slave_config;
 559         dma_cookie_t            cookie;
 560         u32     len = *plen;
 561
 562         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
 563
 564         /* Check that the channels are available */
 565         if (!rxchan || !txchan)
 566                 return -ENODEV;
 567
 568         /* release lock for DMA operations */
 569         atmel_spi_unlock(as);
 570
 571         /* prepare the RX dma transfer */
 572         sg_init_table(&as->dma.sgrx, 1);
 573         if (xfer->rx_buf) {
 574                 as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen;
 575         } else {
 576                 as->dma.sgrx.dma_address = as->buffer_dma;
 577                 if (len > BUFFER_SIZE)
 578                         len = BUFFER_SIZE;
 579         }
 580
 581         /* prepare the TX dma transfer */
 582         sg_init_table(&as->dma.sgtx, 1);
 583         if (xfer->tx_buf) {
 584                 as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen;
 585         } else {
 586                 as->dma.sgtx.dma_address = as->buffer_dma;
 587                 if (len > BUFFER_SIZE)
 588                         len = BUFFER_SIZE;
 589                 memset(as->buffer, 0, len);
 590         }
 591
 592         sg_dma_len(&as->dma.sgtx) = len;
 593         sg_dma_len(&as->dma.sgrx) = len;
 594
 595         *plen = len;
 596
 597         if (atmel_spi_dma_slave_config(as, &slave_config, 8))
 598                 goto err_exit;
 599
 600         /* Send both scatterlists */
 601         rxdesc = rxchan->device->device_prep_slave_sg(rxchan,
 602                                         &as->dma.sgrx,
 603                                         1,
 604                                         DMA_FROM_DEVICE,
 605                                         DMA_PREP_INTERRUPT | DMA_CTRL_ACK,
 606                                         NULL);
 607         if (!rxdesc)
 608                 goto err_dma;
 609
 610         txdesc = txchan->device->device_prep_slave_sg(txchan,
 611                                         &as->dma.sgtx,
 612                                         1,
 613                                         DMA_TO_DEVICE,
 614                                         DMA_PREP_INTERRUPT | DMA_CTRL_ACK,
 615                                         NULL);
 616         if (!txdesc)
 617                 goto err_dma;
 618
 619         dev_dbg(master->dev.parent,
 620                 "  start dma xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 621                 xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 622                 xfer->rx_buf, xfer->rx_dma);
 623
 624         /* Enable relevant interrupts */
 625         spi_writel(as, IER, SPI_BIT(OVRES));
 626
 627         /* Put the callback on the RX transfer only, that should finish last */
 628         rxdesc->callback = dma_callback;
 629         rxdesc->callback_param = master;
 630
 631         /* Submit and fire RX and TX with TX last so we're ready to read! */
 632         cookie = rxdesc->tx_submit(rxdesc);
 633         if (dma_submit_error(cookie))
 634                 goto err_dma;
 635         cookie = txdesc->tx_submit(txdesc);
 636         if (dma_submit_error(cookie))
 637                 goto err_dma;
 638         rxchan->device->device_issue_pending(rxchan);
 639         txchan->device->device_issue_pending(txchan);
 640
 641         /* take back lock */
 642         atmel_spi_lock(as);
 643         return 0;
 644
 645 err_dma:
 646         spi_writel(as, IDR, SPI_BIT(OVRES));
 647         atmel_spi_stop_dma(as);
 648 err_exit:
 649         atmel_spi_lock(as);
 650         return -ENOMEM;
 651 }
 652
 653 static void atmel_spi_next_xfer_data(struct spi_master *master,
 654                                 struct spi_transfer *xfer,
 655                                 dma_addr_t *tx_dma,
 656                                 dma_addr_t *rx_dma,
 657                                 u32 *plen)
 658 {
 659         struct atmel_spi        *as = spi_master_get_devdata(master);
 660         u32                     len = *plen;
 661
 662         /* use scratch buffer only when rx or tx data is unspecified */
 663         if (xfer->rx_buf)
 664                 *rx_dma = xfer->rx_dma + xfer->len - *plen;
 665         else {
 666                 *rx_dma = as->buffer_dma;
 667                 if (len > BUFFER_SIZE)
 668                         len = BUFFER_SIZE;
 669         }
 670
 671         if (xfer->tx_buf)
 672                 *tx_dma = xfer->tx_dma + xfer->len - *plen;
 673         else {
 674                 *tx_dma = as->buffer_dma;
 675                 if (len > BUFFER_SIZE)
 676                         len = BUFFER_SIZE;
 677                 memset(as->buffer, 0, len);
 678                 dma_sync_single_for_device(&as->pdev->dev,
 679                                 as->buffer_dma, len, DMA_TO_DEVICE);
 680         }
 681
 682         *plen = len;
 683 }
 684
 685 /*
 686  * Submit next transfer for PDC.
 687  * lock is held, spi irq is blocked
 688  */
 689 static void atmel_spi_pdc_next_xfer(struct spi_master *master,
 690                                 struct spi_message *msg)
 691 {
 692         struct atmel_spi        *as = spi_master_get_devdata(master);
 693         struct spi_transfer     *xfer;
 694         u32                     len, remaining;
 695         u32                     ieval;
 696         dma_addr_t              tx_dma, rx_dma;
 697
 698         if (!as->current_transfer)
 699                 xfer = list_entry(msg->transfers.next,
 700                                 struct spi_transfer, transfer_list);
 701         else if (!as->next_transfer)
 702                 xfer = list_entry(as->current_transfer->transfer_list.next,
 703                                 struct spi_transfer, transfer_list);
 704         else
 705                 xfer = NULL;
 706
 707         if (xfer) {
 708                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 709
 710                 len = xfer->len;
 711                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 712                 remaining = xfer->len - len;
 713
 714                 spi_writel(as, RPR, rx_dma);
 715                 spi_writel(as, TPR, tx_dma);
 716
 717                 if (msg->spi->bits_per_word > 8)
 718                         len >>= 1;
 719                 spi_writel(as, RCR, len);
 720                 spi_writel(as, TCR, len);
 721
 722                 dev_dbg(&msg->spi->dev,
 723                         "  start xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 724                         xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 725                         xfer->rx_buf, xfer->rx_dma);
 726         } else {
 727                 xfer = as->next_transfer;
 728                 remaining = as->next_remaining_bytes;
 729         }
 730
 731         as->current_transfer = xfer;
 732         as->current_remaining_bytes = remaining;
 733
 734         if (remaining > 0)
 735                 len = remaining;
 736         else if (!atmel_spi_xfer_is_last(msg, xfer)
 737                         && atmel_spi_xfer_can_be_chained(xfer)) {
 738                 xfer = list_entry(xfer->transfer_list.next,
 739                                 struct spi_transfer, transfer_list);
 740                 len = xfer->len;
 741         } else
 742                 xfer = NULL;
 743
 744         as->next_transfer = xfer;
 745
 746         if (xfer) {
 747                 u32     total;
 748
 749                 total = len;
 750                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 751                 as->next_remaining_bytes = total - len;
 752
 753                 spi_writel(as, RNPR, rx_dma);
 754                 spi_writel(as, TNPR, tx_dma);
 755
 756                 if (msg->spi->bits_per_word > 8)
 757                         len >>= 1;
 758                 spi_writel(as, RNCR, len);
 759                 spi_writel(as, TNCR, len);
 760
 761                 dev_dbg(&msg->spi->dev,
 762                         "  next xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 763                         xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 764                         xfer->rx_buf, xfer->rx_dma);
 765                 ieval = SPI_BIT(ENDRX) | SPI_BIT(OVRES);
 766         } else {
 767                 spi_writel(as, RNCR, 0);
 768                 spi_writel(as, TNCR, 0);
 769                 ieval = SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES);
 770         }
 771
 772         /* REVISIT: We're waiting for ENDRX before we start the next
 773          * transfer because we need to handle some difficult timing
 774          * issues otherwise. If we wait for ENDTX in one transfer and
 775          * then starts waiting for ENDRX in the next, it's difficult
 776          * to tell the difference between the ENDRX interrupt we're
 777          * actually waiting for and the ENDRX interrupt of the
 778          * previous transfer.
 779          *
 780          * It should be doable, though. Just not now...
 781          */
 782         spi_writel(as, IER, ieval);
 783         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 784 }
 785
 786 /*
 787  * Choose way to submit next transfer and start it.
 788  * lock is held, spi tasklet is blocked
 789  */
 790 static void atmel_spi_dma_next_xfer(struct spi_master *master,
 791                                 struct spi_message *msg)
 792 {
 793         struct atmel_spi        *as = spi_master_get_devdata(master);
 794         struct spi_transfer     *xfer;
 795         u32     remaining, len;
 796
 797         remaining = as->current_remaining_bytes;
 798         if (remaining) {
 799                 xfer = as->current_transfer;
 800                 len = remaining;
 801         } else {
 802                 if (!as->current_transfer)
 803                         xfer = list_entry(msg->transfers.next,
 804                                 struct spi_transfer, transfer_list);
 805                 else
 806                         xfer = list_entry(
 807                                 as->current_transfer->transfer_list.next,
 808                                         struct spi_transfer, transfer_list);
 809
 810                 as->current_transfer = xfer;
 811                 len = xfer->len;
 812         }
 813
 814         if (atmel_spi_use_dma(as, xfer)) {
 815                 u32 total = len;
 816                 if (!atmel_spi_next_xfer_dma_submit(master, xfer, &len)) {
 817                         as->current_remaining_bytes = total - len;
 818                         return;
 819                 } else {
 820                         dev_err(&msg->spi->dev, "unable to use DMA, fallback to PIO\n");
 821                 }
 822         }
 823
 824         /* use PIO if error appened using DMA */
 825         atmel_spi_next_xfer_pio(master, xfer);
 826 }
 827
 828 static void atmel_spi_next_message(struct spi_master *master)
 829 {
 830         struct atmel_spi        *as = spi_master_get_devdata(master);
 831         struct spi_message      *msg;
 832         struct spi_device       *spi;
 833
 834         BUG_ON(as->current_transfer);
 835
 836         msg = list_entry(as->queue.next, struct spi_message, queue);
 837         spi = msg->spi;
 838
 839         dev_dbg(master->dev.parent, "start message %p for %s\n",
 840                         msg, dev_name(&spi->dev));
 841
 842         /* select chip if it's not still active */
 843         if (as->stay) {
 844                 if (as->stay != spi) {
 845                         cs_deactivate(as, as->stay);
 846                         cs_activate(as, spi);
 847                 }
 848                 as->stay = NULL;
 849         } else
 850                 cs_activate(as, spi);
 851
 852         if (as->use_pdc)
 853                 atmel_spi_pdc_next_xfer(master, msg);
 854         else
 855                 atmel_spi_dma_next_xfer(master, msg);
 856 }
 857
 858 /*
 859  * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
 860  *  - The buffer is either valid for CPU access, else NULL
 861  *  - If the buffer is valid, so is its DMA address
 862  *
 863  * This driver manages the dma address unless message->is_dma_mapped.
 864  */
 865 static int
 866 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 867 {
 868         struct device   *dev = &as->pdev->dev;
 869
 870         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 871         if (xfer->tx_buf) {
 872                 /* tx_buf is a const void* where we need a void * for the dma
 873                  * mapping */
 874                 void *nonconst_tx = (void *)xfer->tx_buf;
 875
 876                 xfer->tx_dma = dma_map_single(dev,
 877                                 nonconst_tx, xfer->len,
 878                                 DMA_TO_DEVICE);
 879                 if (dma_mapping_error(dev, xfer->tx_dma))
 880                         return -ENOMEM;
 881         }
 882         if (xfer->rx_buf) {
 883                 xfer->rx_dma = dma_map_single(dev,
 884                                 xfer->rx_buf, xfer->len,
 885                                 DMA_FROM_DEVICE);
 886                 if (dma_mapping_error(dev, xfer->rx_dma)) {
 887                         if (xfer->tx_buf)
 888                                 dma_unmap_single(dev,
 889                                                 xfer->tx_dma, xfer->len,
 890                                                 DMA_TO_DEVICE);
 891                         return -ENOMEM;
 892                 }
 893         }
 894         return 0;
 895 }
 896
 897 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
 898                                      struct spi_transfer *xfer)
 899 {
 900         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
 901                 dma_unmap_single(master->dev.parent, xfer->tx_dma,
 902                                  xfer->len, DMA_TO_DEVICE);
 903         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
 904                 dma_unmap_single(master->dev.parent, xfer->rx_dma,
 905                                  xfer->len, DMA_FROM_DEVICE);
 906 }
 907
 908 static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
 909 {
 910         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 911 }
 912
 913 static void
 914 atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
 915                 struct spi_message *msg, int stay)
 916 {
 917         if (!stay || as->done_status < 0)
 918                 cs_deactivate(as, msg->spi);
 919         else
 920                 as->stay = msg->spi;
 921
 922         list_del(&msg->queue);
 923         msg->status = as->done_status;
 924
 925         dev_dbg(master->dev.parent,
 926                 "xfer complete: %u bytes transferred\n",
 927                 msg->actual_length);
 928
 929         atmel_spi_unlock(as);
 930         msg->complete(msg->context);
 931         atmel_spi_lock(as);
 932
 933         as->current_transfer = NULL;
 934         as->next_transfer = NULL;
 935         as->done_status = 0;
 936
 937         /* continue if needed */
 938         if (list_empty(&as->queue) || as->stopping) {
 939                 if (as->use_pdc)
 940                         atmel_spi_disable_pdc_transfer(as);
 941         } else {
 942                 atmel_spi_next_message(master);
 943         }
 944 }
 945
 946 /* Called from IRQ
 947  * lock is held
 948  *
 949  * Must update "current_remaining_bytes" to keep track of data
 950  * to transfer.
 951  */
 952 static void
 953 atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
 954 {
 955         u8              *txp;
 956         u8              *rxp;
 957         u16             *txp16;
 958         u16             *rxp16;
 959         unsigned long   xfer_pos = xfer->len - as->current_remaining_bytes;
 960
 961         if (xfer->rx_buf) {
 962                 if (xfer->bits_per_word > 8) {
 963                         rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
 964                         *rxp16 = spi_readl(as, RDR);
 965                 } else {
 966                         rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
 967                         *rxp = spi_readl(as, RDR);
 968                 }
 969         } else {
 970                 spi_readl(as, RDR);
 971         }
 972         if (xfer->bits_per_word > 8) {
 973                 as->current_remaining_bytes -= 2;
 974                 if (as->current_remaining_bytes < 0)
 975                         as->current_remaining_bytes = 0;
 976         } else {
 977                 as->current_remaining_bytes--;
 978         }
 979
 980         if (as->current_remaining_bytes) {
 981                 if (xfer->tx_buf) {
 982                         if (xfer->bits_per_word > 8) {
 983                                 txp16 = (u16 *)(((u8 *)xfer->tx_buf)
 984                                                         + xfer_pos + 2);
 985                                 spi_writel(as, TDR, *txp16);
 986                         } else {
 987                                 txp = ((u8 *)xfer->tx_buf) + xfer_pos + 1;
 988                                 spi_writel(as, TDR, *txp);
 989                         }
 990                 } else {
 991                         spi_writel(as, TDR, 0);
 992                 }
 993         }
 994 }
 995
 996 /* Tasklet
 997  * Called from DMA callback + pio transfer and overrun IRQ.
 998  */
 999 static void atmel_spi_tasklet_func(unsigned long data)
1000 {
1001         struct spi_master       *master = (struct spi_master *)data;
1002         struct atmel_spi        *as = spi_master_get_devdata(master);
1003         struct spi_message      *msg;
1004         struct spi_transfer     *xfer;
1005
1006         dev_vdbg(master->dev.parent, "atmel_spi_tasklet_func\n");
1007
1008         atmel_spi_lock(as);
1009
1010         xfer = as->current_transfer;
1011
1012         if (xfer == NULL)
1013                 /* already been there */
1014                 goto tasklet_out;
1015
1016         msg = list_entry(as->queue.next, struct spi_message, queue);
1017
1018         if (as->current_remaining_bytes == 0) {
1019                 if (as->done_status < 0) {
1020                         /* error happened (overrun) */
1021                         if (atmel_spi_use_dma(as, xfer))
1022                                 atmel_spi_stop_dma(as);
1023                 } else {
1024                         /* only update length if no error */
1025                         msg->actual_length += xfer->len;
1026                 }
1027
1028                 if (atmel_spi_use_dma(as, xfer))
1029                         if (!msg->is_dma_mapped)
1030                                 atmel_spi_dma_unmap_xfer(master, xfer);
1031
1032                 if (xfer->delay_usecs)
1033                         udelay(xfer->delay_usecs);
1034
1035                 if (atmel_spi_xfer_is_last(msg, xfer) || as->done_status < 0) {
1036                         /* report completed (or erroneous) message */
1037                         atmel_spi_msg_done(master, as, msg, xfer->cs_change);
1038                 } else {
1039                         if (xfer->cs_change) {
1040                                 cs_deactivate(as, msg->spi);
1041                                 udelay(1);
1042                                 cs_activate(as, msg->spi);
1043                         }
1044
1045                         /*
1046                          * Not done yet. Submit the next transfer.
1047                          *
1048                          * FIXME handle protocol options for xfer
1049                          */
1050                         atmel_spi_dma_next_xfer(master, msg);
1051                 }
1052         } else {
1053                 /*
1054                  * Keep going, we still have data to send in
1055                  * the current transfer.
1056                  */
1057                 atmel_spi_dma_next_xfer(master, msg);
1058         }
1059
1060 tasklet_out:
1061         atmel_spi_unlock(as);
1062 }
1063
1064 /* Interrupt
1065  *
1066  * No need for locking in this Interrupt handler: done_status is the
1067  * only information modified. What we need is the update of this field
1068  * before tasklet runs. This is ensured by using barrier.
1069  */
1070 static irqreturn_t
1071 atmel_spi_pio_interrupt(int irq, void *dev_id)
1072 {
1073         struct spi_master       *master = dev_id;
1074         struct atmel_spi        *as = spi_master_get_devdata(master);
1075         u32                     status, pending, imr;
1076         struct spi_transfer     *xfer;
1077         int                     ret = IRQ_NONE;
1078
1079         imr = spi_readl(as, IMR);
1080         status = spi_readl(as, SR);
1081         pending = status & imr;
1082
1083         if (pending & SPI_BIT(OVRES)) {
1084                 ret = IRQ_HANDLED;
1085                 spi_writel(as, IDR, SPI_BIT(OVRES));
1086                 dev_warn(master->dev.parent, "overrun\n");
1087
1088                 /*
1089                  * When we get an overrun, we disregard the current
1090                  * transfer. Data will not be copied back from any
1091                  * bounce buffer and msg->actual_len will not be
1092                  * updated with the last xfer.
1093                  *
1094                  * We will also not process any remaning transfers in
1095                  * the message.
1096                  *
1097                  * All actions are done in tasklet with done_status indication
1098                  */
1099                 as->done_status = -EIO;
1100                 smp_wmb();
1101
1102                 /* Clear any overrun happening while cleaning up */
1103                 spi_readl(as, SR);
1104
1105                 tasklet_schedule(&as->tasklet);
1106
1107         } else if (pending & SPI_BIT(RDRF)) {
1108                 atmel_spi_lock(as);
1109
1110                 if (as->current_remaining_bytes) {
1111                         ret = IRQ_HANDLED;
1112                         xfer = as->current_transfer;
1113                         atmel_spi_pump_pio_data(as, xfer);
1114                         if (!as->current_remaining_bytes) {
1115                                 /* no more data to xfer, kick tasklet */
1116                                 spi_writel(as, IDR, pending);
1117                                 tasklet_schedule(&as->tasklet);
1118                         }
1119                 }
1120
1121                 atmel_spi_unlock(as);
1122         } else {
1123                 WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
1124                 ret = IRQ_HANDLED;
1125                 spi_writel(as, IDR, pending);
1126         }
1127
1128         return ret;
1129 }
1130
1131 static irqreturn_t
1132 atmel_spi_pdc_interrupt(int irq, void *dev_id)
1133 {
1134         struct spi_master       *master = dev_id;
1135         struct atmel_spi        *as = spi_master_get_devdata(master);
1136         struct spi_message      *msg;
1137         struct spi_transfer     *xfer;
1138         u32                     status, pending, imr;
1139         int                     ret = IRQ_NONE;
1140
1141         atmel_spi_lock(as);
1142
1143         xfer = as->current_transfer;
1144         msg = list_entry(as->queue.next, struct spi_message, queue);
1145
1146         imr = spi_readl(as, IMR);
1147         status = spi_readl(as, SR);
1148         pending = status & imr;
1149
1150         if (pending & SPI_BIT(OVRES)) {
1151                 int timeout;
1152
1153                 ret = IRQ_HANDLED;
1154
1155                 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
1156                                      | SPI_BIT(OVRES)));
1157
1158                 /*
1159                  * When we get an overrun, we disregard the current
1160                  * transfer. Data will not be copied back from any
1161                  * bounce buffer and msg->actual_len will not be
1162                  * updated with the last xfer.
1163                  *
1164                  * We will also not process any remaning transfers in
1165                  * the message.
1166                  *
1167                  * First, stop the transfer and unmap the DMA buffers.
1168                  */
1169                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1170                 if (!msg->is_dma_mapped)
1171                         atmel_spi_dma_unmap_xfer(master, xfer);
1172
1173                 /* REVISIT: udelay in irq is unfriendly */
1174                 if (xfer->delay_usecs)
1175                         udelay(xfer->delay_usecs);
1176
1177                 dev_warn(master->dev.parent, "overrun (%u/%u remaining)\n",
1178                          spi_readl(as, TCR), spi_readl(as, RCR));
1179
1180                 /*
1181                  * Clean up DMA registers and make sure the data
1182                  * registers are empty.
1183                  */
1184                 spi_writel(as, RNCR, 0);
1185                 spi_writel(as, TNCR, 0);
1186                 spi_writel(as, RCR, 0);
1187                 spi_writel(as, TCR, 0);
1188                 for (timeout = 1000; timeout; timeout--)
1189                         if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
1190                                 break;
1191                 if (!timeout)
1192                         dev_warn(master->dev.parent,
1193                                  "timeout waiting for TXEMPTY");
1194                 while (spi_readl(as, SR) & SPI_BIT(RDRF))
1195                         spi_readl(as, RDR);
1196
1197                 /* Clear any overrun happening while cleaning up */
1198                 spi_readl(as, SR);
1199
1200                 as->done_status = -EIO;
1201                 atmel_spi_msg_done(master, as, msg, 0);
1202         } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
1203                 ret = IRQ_HANDLED;
1204
1205                 spi_writel(as, IDR, pending);
1206
1207                 if (as->current_remaining_bytes == 0) {
1208                         msg->actual_length += xfer->len;
1209
1210                         if (!msg->is_dma_mapped)
1211                                 atmel_spi_dma_unmap_xfer(master, xfer);
1212
1213                         /* REVISIT: udelay in irq is unfriendly */
1214                         if (xfer->delay_usecs)
1215                                 udelay(xfer->delay_usecs);
1216
1217                         if (atmel_spi_xfer_is_last(msg, xfer)) {
1218                                 /* report completed message */
1219                                 atmel_spi_msg_done(master, as, msg,
1220                                                 xfer->cs_change);
1221                         } else {
1222                                 if (xfer->cs_change) {
1223                                         cs_deactivate(as, msg->spi);
1224                                         udelay(1);
1225                                         cs_activate(as, msg->spi);
1226                                 }
1227
1228                                 /*
1229                                  * Not done yet. Submit the next transfer.
1230                                  *
1231                                  * FIXME handle protocol options for xfer
1232                                  */
1233                                 atmel_spi_pdc_next_xfer(master, msg);
1234                         }
1235                 } else {
1236                         /*
1237                          * Keep going, we still have data to send in
1238                          * the current transfer.
1239                          */
1240                         atmel_spi_pdc_next_xfer(master, msg);
1241                 }
1242         }
1243
1244         atmel_spi_unlock(as);
1245
1246         return ret;
1247 }
1248
1249 static int atmel_spi_setup(struct spi_device *spi)
1250 {
1251         struct atmel_spi        *as;
1252         struct atmel_spi_device *asd;
1253         u32                     scbr, csr;
1254         unsigned int            bits = spi->bits_per_word;
1255         unsigned long           bus_hz;
1256         unsigned int            npcs_pin;
1257         int                     ret;
1258
1259         as = spi_master_get_devdata(spi->master);
1260
1261         if (as->stopping)
1262                 return -ESHUTDOWN;
1263
1264         if (spi->chip_select > spi->master->num_chipselect) {
1265                 dev_dbg(&spi->dev,
1266                                 "setup: invalid chipselect %u (%u defined)\n",
1267                                 spi->chip_select, spi->master->num_chipselect);
1268                 return -EINVAL;
1269         }
1270
1271         if (bits < 8 || bits > 16) {
1272                 dev_dbg(&spi->dev,
1273                                 "setup: invalid bits_per_word %u (8 to 16)\n",
1274                                 bits);
1275                 return -EINVAL;
1276         }
1277
1278         /* see notes above re chipselect */
1279         if (!atmel_spi_is_v2(as)
1280                         && spi->chip_select == 0
1281                         && (spi->mode & SPI_CS_HIGH)) {
1282                 dev_dbg(&spi->dev, "setup: can't be active-high\n");
1283                 return -EINVAL;
1284         }
1285
1286         /* v1 chips start out at half the peripheral bus speed. */
1287         bus_hz = clk_get_rate(as->clk);
1288         if (!atmel_spi_is_v2(as))
1289                 bus_hz /= 2;
1290
1291         if (spi->max_speed_hz) {
1292                 /*
1293                  * Calculate the lowest divider that satisfies the
1294                  * constraint, assuming div32/fdiv/mbz == 0.
1295                  */
1296                 scbr = DIV_ROUND_UP(bus_hz, spi->max_speed_hz);
1297
1298                 /*
1299                  * If the resulting divider doesn't fit into the
1300                  * register bitfield, we can't satisfy the constraint.
1301                  */
1302                 if (scbr >= (1 << SPI_SCBR_SIZE)) {
1303                         dev_dbg(&spi->dev,
1304                                 "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
1305                                 spi->max_speed_hz, scbr, bus_hz/255);
1306                         return -EINVAL;
1307                 }
1308         } else
1309                 /* speed zero means "as slow as possible" */
1310                 scbr = 0xff;
1311
1312         csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
1313         if (spi->mode & SPI_CPOL)
1314                 csr |= SPI_BIT(CPOL);
1315         if (!(spi->mode & SPI_CPHA))
1316                 csr |= SPI_BIT(NCPHA);
1317
1318         /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
1319          *
1320          * DLYBCT would add delays between words, slowing down transfers.
1321          * It could potentially be useful to cope with DMA bottlenecks, but
1322          * in those cases it's probably best to just use a lower bitrate.
1323          */
1324         csr |= SPI_BF(DLYBS, 0);
1325         csr |= SPI_BF(DLYBCT, 0);
1326
1327         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
1328         npcs_pin = (unsigned int)spi->controller_data;
1329
1330         if (gpio_is_valid(spi->cs_gpio))
1331                 npcs_pin = spi->cs_gpio;
1332
1333         asd = spi->controller_state;
1334         if (!asd) {
1335                 asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
1336                 if (!asd)
1337                         return -ENOMEM;
1338
1339                 ret = gpio_request(npcs_pin, dev_name(&spi->dev));
1340                 if (ret) {
1341                         kfree(asd);
1342                         return ret;
1343                 }
1344
1345                 asd->npcs_pin = npcs_pin;
1346                 spi->controller_state = asd;
1347                 gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
1348         } else {
1349                 atmel_spi_lock(as);
1350                 if (as->stay == spi)
1351                         as->stay = NULL;
1352                 cs_deactivate(as, spi);
1353                 atmel_spi_unlock(as);
1354         }
1355
1356         asd->csr = csr;
1357
1358         dev_dbg(&spi->dev,
1359                 "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
1360                 bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);
1361
1362         if (!atmel_spi_is_v2(as))
1363                 spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
1364
1365         return 0;
1366 }
1367
1368 static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
1369 {
1370         struct atmel_spi        *as;
1371         struct spi_transfer     *xfer;
1372         struct device           *controller = spi->master->dev.parent;
1373         u8                      bits;
1374         struct atmel_spi_device *asd;
1375
1376         as = spi_master_get_devdata(spi->master);
1377
1378         dev_dbg(controller, "new message %p submitted for %s\n",
1379                         msg, dev_name(&spi->dev));
1380
1381         if (unlikely(list_empty(&msg->transfers)))
1382                 return -EINVAL;
1383
1384         if (as->stopping)
1385                 return -ESHUTDOWN;
1386
1387         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1388                 if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1389                         dev_dbg(&spi->dev, "missing rx or tx buf\n");
1390                         return -EINVAL;
1391                 }
1392
1393                 if (xfer->bits_per_word) {
1394                         asd = spi->controller_state;
1395                         bits = (asd->csr >> 4) & 0xf;
1396                         if (bits != xfer->bits_per_word - 8) {
1397                                 dev_dbg(&spi->dev, "you can't yet change "
1398                                          "bits_per_word in transfers\n");
1399                                 return -ENOPROTOOPT;
1400                         }
1401                 }
1402
1403                 if (xfer->bits_per_word > 8) {
1404                         if (xfer->len % 2) {
1405                                 dev_dbg(&spi->dev, "buffer len should be 16 bits aligned\n");
1406                                 return -EINVAL;
1407                         }
1408                 }
1409
1410                 /* FIXME implement these protocol options!! */
1411                 if (xfer->speed_hz) {
1412                         dev_dbg(&spi->dev, "no protocol options yet\n");
1413                         return -ENOPROTOOPT;
1414                 }
1415
1416                 /*
1417                  * DMA map early, for performance (empties dcache ASAP) and
1418                  * better fault reporting.
1419                  */
1420                 if ((!msg->is_dma_mapped) && (atmel_spi_use_dma(as, xfer)
1421                         || as->use_pdc)) {
1422                         if (atmel_spi_dma_map_xfer(as, xfer) < 0)
1423                                 return -ENOMEM;
1424                 }
1425         }
1426
1427 #ifdef VERBOSE
1428         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1429                 dev_dbg(controller,
1430                         "  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
1431                         xfer, xfer->len,
1432                         xfer->tx_buf, xfer->tx_dma,
1433                         xfer->rx_buf, xfer->rx_dma);
1434         }
1435 #endif
1436
1437         msg->status = -EINPROGRESS;
1438         msg->actual_length = 0;
1439
1440         atmel_spi_lock(as);
1441         list_add_tail(&msg->queue, &as->queue);
1442         if (!as->current_transfer)
1443                 atmel_spi_next_message(spi->master);
1444         atmel_spi_unlock(as);
1445
1446         return 0;
1447 }
1448
1449 static void atmel_spi_cleanup(struct spi_device *spi)
1450 {
1451         struct atmel_spi        *as = spi_master_get_devdata(spi->master);
1452         struct atmel_spi_device *asd = spi->controller_state;
1453         unsigned                gpio = (unsigned) spi->controller_data;
1454
1455         if (!asd)
1456                 return;
1457
1458         atmel_spi_lock(as);
1459         if (as->stay == spi) {
1460                 as->stay = NULL;
1461                 cs_deactivate(as, spi);
1462         }
1463         atmel_spi_unlock(as);
1464
1465         spi->controller_state = NULL;
1466         gpio_free(gpio);
1467         kfree(asd);
1468 }
1469
1470 static inline unsigned int atmel_get_version(struct atmel_spi *as)
1471 {
1472         return spi_readl(as, VERSION) & 0x00000fff;
1473 }
1474
1475 static void atmel_get_caps(struct atmel_spi *as)
1476 {
1477         unsigned int version;
1478
1479         version = atmel_get_version(as);
1480         dev_info(&as->pdev->dev, "version: 0x%x\n", version);
1481
1482         as->caps.is_spi2 = version > 0x121;
1483         as->caps.has_wdrbt = version >= 0x210;
1484         as->caps.has_dma_support = version >= 0x212;
1485 }
1486
1487 /*-------------------------------------------------------------------------*/
1488
1489 static int atmel_spi_probe(struct platform_device *pdev)
1490 {
1491         struct resource         *regs;
1492         int                     irq;
1493         struct clk              *clk;
1494         int                     ret;
1495         struct spi_master       *master;
1496         struct atmel_spi        *as;
1497
1498         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1499         if (!regs)
1500                 return -ENXIO;
1501
1502         irq = platform_get_irq(pdev, 0);
1503         if (irq < 0)
1504                 return irq;
1505
1506         clk = clk_get(&pdev->dev, "spi_clk");
1507         if (IS_ERR(clk))
1508                 return PTR_ERR(clk);
1509
1510         /* setup spi core then atmel-specific driver state */
1511         ret = -ENOMEM;
1512         master = spi_alloc_master(&pdev->dev, sizeof *as);
1513         if (!master)
1514                 goto out_free;
1515
1516         /* the spi->mode bits understood by this driver: */
1517         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1518
1519         master->dev.of_node = pdev->dev.of_node;
1520         master->bus_num = pdev->id;
1521         master->num_chipselect = master->dev.of_node ? 0 : 4;
1522         master->setup = atmel_spi_setup;
1523         master->transfer = atmel_spi_transfer;
1524         master->cleanup = atmel_spi_cleanup;
1525         platform_set_drvdata(pdev, master);
1526
1527         as = spi_master_get_devdata(master);
1528
1529         /*
1530          * Scratch buffer is used for throwaway rx and tx data.
1531          * It's coherent to minimize dcache pollution.
1532          */
1533         as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
1534                                         &as->buffer_dma, GFP_KERNEL);
1535         if (!as->buffer)
1536                 goto out_free;
1537
1538         spin_lock_init(&as->lock);
1539         INIT_LIST_HEAD(&as->queue);
1540
1541         as->pdev = pdev;
1542         as->regs = ioremap(regs->start, resource_size(regs));
1543         if (!as->regs)
1544                 goto out_free_buffer;
1545         as->phybase = regs->start;
1546         as->irq = irq;
1547         as->clk = clk;
1548
1549         atmel_get_caps(as);
1550
1551         as->use_dma = false;
1552         as->use_pdc = false;
1553         if (as->caps.has_dma_support) {
1554                 if (atmel_spi_configure_dma(as) == 0)
1555                         as->use_dma = true;
1556         } else {
1557                 as->use_pdc = true;
1558         }
1559
1560         if (as->caps.has_dma_support && !as->use_dma)
1561                 dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
1562
1563         if (as->use_pdc) {
1564                 ret = request_irq(irq, atmel_spi_pdc_interrupt, 0,
1565                                         dev_name(&pdev->dev), master);
1566         } else {
1567                 tasklet_init(&as->tasklet, atmel_spi_tasklet_func,
1568                                         (unsigned long)master);
1569
1570                 ret = request_irq(irq, atmel_spi_pio_interrupt, 0,
1571                                         dev_name(&pdev->dev), master);
1572         }
1573         if (ret)
1574                 goto out_unmap_regs;
1575
1576         /* Initialize the hardware */
1577         clk_enable(clk);
1578         spi_writel(as, CR, SPI_BIT(SWRST));
1579         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1580         if (as->caps.has_wdrbt) {
1581                 spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
1582                                 | SPI_BIT(MSTR));
1583         } else {
1584                 spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
1585         }
1586
1587         if (as->use_pdc)
1588                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1589         spi_writel(as, CR, SPI_BIT(SPIEN));
1590
1591         /* go! */
1592         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
1593                         (unsigned long)regs->start, irq);
1594
1595         ret = spi_register_master(master);
1596         if (ret)
1597                 goto out_free_dma;
1598
1599         return 0;
1600
1601 out_free_dma:
1602         if (as->use_dma)
1603                 atmel_spi_release_dma(as);
1604
1605         spi_writel(as, CR, SPI_BIT(SWRST));
1606         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1607         clk_disable(clk);
1608         free_irq(irq, master);
1609 out_unmap_regs:
1610         iounmap(as->regs);
1611 out_free_buffer:
1612         if (!as->use_pdc)
1613                 tasklet_kill(&as->tasklet);
1614         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1615                         as->buffer_dma);
1616 out_free:
1617         clk_put(clk);
1618         spi_master_put(master);
1619         return ret;
1620 }
1621
1622 static int atmel_spi_remove(struct platform_device *pdev)
1623 {
1624         struct spi_master       *master = platform_get_drvdata(pdev);
1625         struct atmel_spi        *as = spi_master_get_devdata(master);
1626         struct spi_message      *msg;
1627         struct spi_transfer     *xfer;
1628
1629         /* reset the hardware and block queue progress */
1630         spin_lock_irq(&as->lock);
1631         as->stopping = 1;
1632         if (as->use_dma) {
1633                 atmel_spi_stop_dma(as);
1634                 atmel_spi_release_dma(as);
1635         }
1636
1637         spi_writel(as, CR, SPI_BIT(SWRST));
1638         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1639         spi_readl(as, SR);
1640         spin_unlock_irq(&as->lock);
1641
1642         /* Terminate remaining queued transfers */
1643         list_for_each_entry(msg, &as->queue, queue) {
1644                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1645                         if (!msg->is_dma_mapped
1646                                 && (atmel_spi_use_dma(as, xfer)
1647                                         || as->use_pdc))
1648                                 atmel_spi_dma_unmap_xfer(master, xfer);
1649                 }
1650                 msg->status = -ESHUTDOWN;
1651                 msg->complete(msg->context);
1652         }
1653
1654         if (!as->use_pdc)
1655                 tasklet_kill(&as->tasklet);
1656         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1657                         as->buffer_dma);
1658
1659         clk_disable(as->clk);
1660         clk_put(as->clk);
1661         free_irq(as->irq, master);
1662         iounmap(as->regs);
1663
1664         spi_unregister_master(master);
1665
1666         return 0;
1667 }
1668
1669 #ifdef  CONFIG_PM
1670
1671 static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
1672 {
1673         struct spi_master       *master = platform_get_drvdata(pdev);
1674         struct atmel_spi        *as = spi_master_get_devdata(master);
1675
1676         clk_disable(as->clk);
1677         return 0;
1678 }
1679
1680 static int atmel_spi_resume(struct platform_device *pdev)
1681 {
1682         struct spi_master       *master = platform_get_drvdata(pdev);
1683         struct atmel_spi        *as = spi_master_get_devdata(master);
1684
1685         clk_enable(as->clk);
1686         return 0;
1687 }
1688
1689 #else
1690 #define atmel_spi_suspend       NULL
1691 #define atmel_spi_resume        NULL
1692 #endif
1693
1694 #if defined(CONFIG_OF)
1695 static const struct of_device_id atmel_spi_dt_ids[] = {
1696         { .compatible = "atmel,at91rm9200-spi" },
1697         { /* sentinel */ }
1698 };
1699
1700 MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
1701 #endif
1702
1703 static struct platform_driver atmel_spi_driver = {
1704         .driver         = {
1705                 .name   = "atmel_spi",
1706                 .owner  = THIS_MODULE,
1707                 .of_match_table = of_match_ptr(atmel_spi_dt_ids),
1708         },
1709         .suspend        = atmel_spi_suspend,
1710         .resume         = atmel_spi_resume,
1711         .probe          = atmel_spi_probe,
1712         .remove         = atmel_spi_remove,
1713 };
1714 module_platform_driver(atmel_spi_driver);
1715
1716 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
1717 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1718 MODULE_LICENSE("GPL");
1719 MODULE_ALIAS("platform:atmel_spi");