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 #define SPI_DMA_TIMEOUT         (msecs_to_jiffies(1000))
 193
 194 struct atmel_spi_dma {
 195         struct dma_chan                 *chan_rx;
 196         struct dma_chan                 *chan_tx;
 197         struct scatterlist              sgrx;
 198         struct scatterlist              sgtx;
 199         struct dma_async_tx_descriptor  *data_desc_rx;
 200         struct dma_async_tx_descriptor  *data_desc_tx;
 201
 202         struct at_dma_slave     dma_slave;
 203 };
 204
 205 struct atmel_spi_caps {
 206         bool    is_spi2;
 207         bool    has_wdrbt;
 208         bool    has_dma_support;
 209 };
 210
 211 /*
 212  * The core SPI transfer engine just talks to a register bank to set up
 213  * DMA transfers; transfer queue progress is driven by IRQs.  The clock
 214  * framework provides the base clock, subdivided for each spi_device.
 215  */
 216 struct atmel_spi {
 217         spinlock_t              lock;
 218         unsigned long           flags;
 219
 220         phys_addr_t             phybase;
 221         void __iomem            *regs;
 222         int                     irq;
 223         struct clk              *clk;
 224         struct platform_device  *pdev;
 225
 226         struct spi_transfer     *current_transfer;
 227         unsigned long           current_remaining_bytes;
 228         int                     done_status;
 229
 230         struct completion       xfer_completion;
 231
 232         /* scratch buffer */
 233         void                    *buffer;
 234         dma_addr_t              buffer_dma;
 235
 236         struct atmel_spi_caps   caps;
 237
 238         bool                    use_dma;
 239         bool                    use_pdc;
 240         /* dmaengine data */
 241         struct atmel_spi_dma    dma;
 242
 243         bool                    keep_cs;
 244         bool                    cs_active;
 245 };
 246
 247 /* Controller-specific per-slave state */
 248 struct atmel_spi_device {
 249         unsigned int            npcs_pin;
 250         u32                     csr;
 251 };
 252
 253 #define BUFFER_SIZE             PAGE_SIZE
 254 #define INVALID_DMA_ADDRESS     0xffffffff
 255
 256 /*
 257  * Version 2 of the SPI controller has
 258  *  - CR.LASTXFER
 259  *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
 260  *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
 261  *  - SPI_CSRx.CSAAT
 262  *  - SPI_CSRx.SBCR allows faster clocking
 263  */
 264 static bool atmel_spi_is_v2(struct atmel_spi *as)
 265 {
 266         return as->caps.is_spi2;
 267 }
 268
 269 /*
 270  * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
 271  * they assume that spi slave device state will not change on deselect, so
 272  * that automagic deselection is OK.  ("NPCSx rises if no data is to be
 273  * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
 274  * controllers have CSAAT and friends.
 275  *
 276  * Since the CSAAT functionality is a bit weird on newer controllers as
 277  * well, we use GPIO to control nCSx pins on all controllers, updating
 278  * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
 279  * support active-high chipselects despite the controller's belief that
 280  * only active-low devices/systems exists.
 281  *
 282  * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
 283  * right when driven with GPIO.  ("Mode Fault does not allow more than one
 284  * Master on Chip Select 0.")  No workaround exists for that ... so for
 285  * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
 286  * and (c) will trigger that first erratum in some cases.
 287  */
 288
 289 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 290 {
 291         struct atmel_spi_device *asd = spi->controller_state;
 292         unsigned active = spi->mode & SPI_CS_HIGH;
 293         u32 mr;
 294
 295         if (atmel_spi_is_v2(as)) {
 296                 spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
 297                 /* For the low SPI version, there is a issue that PDC transfer
 298                  * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
 299                  */
 300                 spi_writel(as, CSR0, asd->csr);
 301                 if (as->caps.has_wdrbt) {
 302                         spi_writel(as, MR,
 303                                         SPI_BF(PCS, ~(0x01 << spi->chip_select))
 304                                         | SPI_BIT(WDRBT)
 305                                         | SPI_BIT(MODFDIS)
 306                                         | SPI_BIT(MSTR));
 307                 } else {
 308                         spi_writel(as, MR,
 309                                         SPI_BF(PCS, ~(0x01 << spi->chip_select))
 310                                         | SPI_BIT(MODFDIS)
 311                                         | SPI_BIT(MSTR));
 312                 }
 313
 314                 mr = spi_readl(as, MR);
 315                 gpio_set_value(asd->npcs_pin, active);
 316         } else {
 317                 u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
 318                 int i;
 319                 u32 csr;
 320
 321                 /* Make sure clock polarity is correct */
 322                 for (i = 0; i < spi->master->num_chipselect; i++) {
 323                         csr = spi_readl(as, CSR0 + 4 * i);
 324                         if ((csr ^ cpol) & SPI_BIT(CPOL))
 325                                 spi_writel(as, CSR0 + 4 * i,
 326                                                 csr ^ SPI_BIT(CPOL));
 327                 }
 328
 329                 mr = spi_readl(as, MR);
 330                 mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
 331                 if (spi->chip_select != 0)
 332                         gpio_set_value(asd->npcs_pin, active);
 333                 spi_writel(as, MR, mr);
 334         }
 335
 336         dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
 337                         asd->npcs_pin, active ? " (high)" : "",
 338                         mr);
 339 }
 340
 341 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 342 {
 343         struct atmel_spi_device *asd = spi->controller_state;
 344         unsigned active = spi->mode & SPI_CS_HIGH;
 345         u32 mr;
 346
 347         /* only deactivate *this* device; sometimes transfers to
 348          * another device may be active when this routine is called.
 349          */
 350         mr = spi_readl(as, MR);
 351         if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
 352                 mr = SPI_BFINS(PCS, 0xf, mr);
 353                 spi_writel(as, MR, mr);
 354         }
 355
 356         dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
 357                         asd->npcs_pin, active ? " (low)" : "",
 358                         mr);
 359
 360         if (atmel_spi_is_v2(as) || spi->chip_select != 0)
 361                 gpio_set_value(asd->npcs_pin, !active);
 362 }
 363
 364 static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
 365 {
 366         spin_lock_irqsave(&as->lock, as->flags);
 367 }
 368
 369 static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock)
 370 {
 371         spin_unlock_irqrestore(&as->lock, as->flags);
 372 }
 373
 374 static inline bool atmel_spi_use_dma(struct atmel_spi *as,
 375                                 struct spi_transfer *xfer)
 376 {
 377         return as->use_dma && xfer->len >= DMA_MIN_BYTES;
 378 }
 379
 380 static int atmel_spi_dma_slave_config(struct atmel_spi *as,
 381                                 struct dma_slave_config *slave_config,
 382                                 u8 bits_per_word)
 383 {
 384         int err = 0;
 385
 386         if (bits_per_word > 8) {
 387                 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 388                 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 389         } else {
 390                 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 391                 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 392         }
 393
 394         slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
 395         slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR;
 396         slave_config->src_maxburst = 1;
 397         slave_config->dst_maxburst = 1;
 398         slave_config->device_fc = false;
 399
 400         slave_config->direction = DMA_MEM_TO_DEV;
 401         if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) {
 402                 dev_err(&as->pdev->dev,
 403                         "failed to configure tx dma channel\n");
 404                 err = -EINVAL;
 405         }
 406
 407         slave_config->direction = DMA_DEV_TO_MEM;
 408         if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) {
 409                 dev_err(&as->pdev->dev,
 410                         "failed to configure rx dma channel\n");
 411                 err = -EINVAL;
 412         }
 413
 414         return err;
 415 }
 416
 417 static bool filter(struct dma_chan *chan, void *pdata)
 418 {
 419         struct atmel_spi_dma *sl_pdata = pdata;
 420         struct at_dma_slave *sl;
 421
 422         if (!sl_pdata)
 423                 return false;
 424
 425         sl = &sl_pdata->dma_slave;
 426         if (sl->dma_dev == chan->device->dev) {
 427                 chan->private = sl;
 428                 return true;
 429         } else {
 430                 return false;
 431         }
 432 }
 433
 434 static int atmel_spi_configure_dma(struct atmel_spi *as)
 435 {
 436         struct dma_slave_config slave_config;
 437         struct device *dev = &as->pdev->dev;
 438         int err;
 439
 440         dma_cap_mask_t mask;
 441         dma_cap_zero(mask);
 442         dma_cap_set(DMA_SLAVE, mask);
 443
 444         as->dma.chan_tx = dma_request_slave_channel_compat(mask, filter,
 445                                                            &as->dma,
 446                                                            dev, "tx");
 447         if (!as->dma.chan_tx) {
 448                 dev_err(dev,
 449                         "DMA TX channel not available, SPI unable to use DMA\n");
 450                 err = -EBUSY;
 451                 goto error;
 452         }
 453
 454         as->dma.chan_rx = dma_request_slave_channel_compat(mask, filter,
 455                                                            &as->dma,
 456                                                            dev, "rx");
 457
 458         if (!as->dma.chan_rx) {
 459                 dev_err(dev,
 460                         "DMA RX channel not available, SPI unable to use DMA\n");
 461                 err = -EBUSY;
 462                 goto error;
 463         }
 464
 465         err = atmel_spi_dma_slave_config(as, &slave_config, 8);
 466         if (err)
 467                 goto error;
 468
 469         dev_info(&as->pdev->dev,
 470                         "Using %s (tx) and %s (rx) for DMA transfers\n",
 471                         dma_chan_name(as->dma.chan_tx),
 472                         dma_chan_name(as->dma.chan_rx));
 473         return 0;
 474 error:
 475         if (as->dma.chan_rx)
 476                 dma_release_channel(as->dma.chan_rx);
 477         if (as->dma.chan_tx)
 478                 dma_release_channel(as->dma.chan_tx);
 479         return err;
 480 }
 481
 482 static void atmel_spi_stop_dma(struct atmel_spi *as)
 483 {
 484         if (as->dma.chan_rx)
 485                 as->dma.chan_rx->device->device_control(as->dma.chan_rx,
 486                                                         DMA_TERMINATE_ALL, 0);
 487         if (as->dma.chan_tx)
 488                 as->dma.chan_tx->device->device_control(as->dma.chan_tx,
 489                                                         DMA_TERMINATE_ALL, 0);
 490 }
 491
 492 static void atmel_spi_release_dma(struct atmel_spi *as)
 493 {
 494         if (as->dma.chan_rx)
 495                 dma_release_channel(as->dma.chan_rx);
 496         if (as->dma.chan_tx)
 497                 dma_release_channel(as->dma.chan_tx);
 498 }
 499
 500 /* This function is called by the DMA driver from tasklet context */
 501 static void dma_callback(void *data)
 502 {
 503         struct spi_master       *master = data;
 504         struct atmel_spi        *as = spi_master_get_devdata(master);
 505
 506         complete(&as->xfer_completion);
 507 }
 508
 509 /*
 510  * Next transfer using PIO.
 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         unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
 517
 518         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
 519
 520         /* Make sure data is not remaining in RDR */
 521         spi_readl(as, RDR);
 522         while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
 523                 spi_readl(as, RDR);
 524                 cpu_relax();
 525         }
 526
 527         if (xfer->tx_buf) {
 528                 if (xfer->bits_per_word > 8)
 529                         spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
 530                 else
 531                         spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
 532         } else {
 533                 spi_writel(as, TDR, 0);
 534         }
 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  */
 548 static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
 549                                 struct spi_transfer *xfer,
 550                                 u32 *plen)
 551 {
 552         struct atmel_spi        *as = spi_master_get_devdata(master);
 553         struct dma_chan         *rxchan = as->dma.chan_rx;
 554         struct dma_chan         *txchan = as->dma.chan_tx;
 555         struct dma_async_tx_descriptor *rxdesc;
 556         struct dma_async_tx_descriptor *txdesc;
 557         struct dma_slave_config slave_config;
 558         dma_cookie_t            cookie;
 559         u32     len = *plen;
 560
 561         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
 562
 563         /* Check that the channels are available */
 564         if (!rxchan || !txchan)
 565                 return -ENODEV;
 566
 567         /* release lock for DMA operations */
 568         atmel_spi_unlock(as);
 569
 570         /* prepare the RX dma transfer */
 571         sg_init_table(&as->dma.sgrx, 1);
 572         if (xfer->rx_buf) {
 573                 as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen;
 574         } else {
 575                 as->dma.sgrx.dma_address = as->buffer_dma;
 576                 if (len > BUFFER_SIZE)
 577                         len = BUFFER_SIZE;
 578         }
 579
 580         /* prepare the TX dma transfer */
 581         sg_init_table(&as->dma.sgtx, 1);
 582         if (xfer->tx_buf) {
 583                 as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen;
 584         } else {
 585                 as->dma.sgtx.dma_address = as->buffer_dma;
 586                 if (len > BUFFER_SIZE)
 587                         len = BUFFER_SIZE;
 588                 memset(as->buffer, 0, len);
 589         }
 590
 591         sg_dma_len(&as->dma.sgtx) = len;
 592         sg_dma_len(&as->dma.sgrx) = len;
 593
 594         *plen = len;
 595
 596         if (atmel_spi_dma_slave_config(as, &slave_config, 8))
 597                 goto err_exit;
 598
 599         /* Send both scatterlists */
 600         rxdesc = rxchan->device->device_prep_slave_sg(rxchan,
 601                                         &as->dma.sgrx,
 602                                         1,
 603                                         DMA_FROM_DEVICE,
 604                                         DMA_PREP_INTERRUPT | DMA_CTRL_ACK,
 605                                         NULL);
 606         if (!rxdesc)
 607                 goto err_dma;
 608
 609         txdesc = txchan->device->device_prep_slave_sg(txchan,
 610                                         &as->dma.sgtx,
 611                                         1,
 612                                         DMA_TO_DEVICE,
 613                                         DMA_PREP_INTERRUPT | DMA_CTRL_ACK,
 614                                         NULL);
 615         if (!txdesc)
 616                 goto err_dma;
 617
 618         dev_dbg(master->dev.parent,
 619                 "  start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 620                 xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
 621                 xfer->rx_buf, (unsigned long long)xfer->rx_dma);
 622
 623         /* Enable relevant interrupts */
 624         spi_writel(as, IER, SPI_BIT(OVRES));
 625
 626         /* Put the callback on the RX transfer only, that should finish last */
 627         rxdesc->callback = dma_callback;
 628         rxdesc->callback_param = master;
 629
 630         /* Submit and fire RX and TX with TX last so we're ready to read! */
 631         cookie = rxdesc->tx_submit(rxdesc);
 632         if (dma_submit_error(cookie))
 633                 goto err_dma;
 634         cookie = txdesc->tx_submit(txdesc);
 635         if (dma_submit_error(cookie))
 636                 goto err_dma;
 637         rxchan->device->device_issue_pending(rxchan);
 638         txchan->device->device_issue_pending(txchan);
 639
 640         /* take back lock */
 641         atmel_spi_lock(as);
 642         return 0;
 643
 644 err_dma:
 645         spi_writel(as, IDR, SPI_BIT(OVRES));
 646         atmel_spi_stop_dma(as);
 647 err_exit:
 648         atmel_spi_lock(as);
 649         return -ENOMEM;
 650 }
 651
 652 static void atmel_spi_next_xfer_data(struct spi_master *master,
 653                                 struct spi_transfer *xfer,
 654                                 dma_addr_t *tx_dma,
 655                                 dma_addr_t *rx_dma,
 656                                 u32 *plen)
 657 {
 658         struct atmel_spi        *as = spi_master_get_devdata(master);
 659         u32                     len = *plen;
 660
 661         /* use scratch buffer only when rx or tx data is unspecified */
 662         if (xfer->rx_buf)
 663                 *rx_dma = xfer->rx_dma + xfer->len - *plen;
 664         else {
 665                 *rx_dma = as->buffer_dma;
 666                 if (len > BUFFER_SIZE)
 667                         len = BUFFER_SIZE;
 668         }
 669
 670         if (xfer->tx_buf)
 671                 *tx_dma = xfer->tx_dma + xfer->len - *plen;
 672         else {
 673                 *tx_dma = as->buffer_dma;
 674                 if (len > BUFFER_SIZE)
 675                         len = BUFFER_SIZE;
 676                 memset(as->buffer, 0, len);
 677                 dma_sync_single_for_device(&as->pdev->dev,
 678                                 as->buffer_dma, len, DMA_TO_DEVICE);
 679         }
 680
 681         *plen = len;
 682 }
 683
 684 static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
 685                                     struct spi_device *spi,
 686                                     struct spi_transfer *xfer)
 687 {
 688         u32                     scbr, csr;
 689         unsigned long           bus_hz;
 690
 691         /* v1 chips start out at half the peripheral bus speed. */
 692         bus_hz = clk_get_rate(as->clk);
 693         if (!atmel_spi_is_v2(as))
 694                 bus_hz /= 2;
 695
 696         /*
 697          * Calculate the lowest divider that satisfies the
 698          * constraint, assuming div32/fdiv/mbz == 0.
 699          */
 700         if (xfer->speed_hz)
 701                 scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
 702         else
 703                 /*
 704                  * This can happend if max_speed is null.
 705                  * In this case, we set the lowest possible speed
 706                  */
 707                 scbr = 0xff;
 708
 709         /*
 710          * If the resulting divider doesn't fit into the
 711          * register bitfield, we can't satisfy the constraint.
 712          */
 713         if (scbr >= (1 << SPI_SCBR_SIZE)) {
 714                 dev_err(&spi->dev,
 715                         "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
 716                         xfer->speed_hz, scbr, bus_hz/255);
 717                 return -EINVAL;
 718         }
 719         if (scbr == 0) {
 720                 dev_err(&spi->dev,
 721                         "setup: %d Hz too high, scbr %u; max %ld Hz\n",
 722                         xfer->speed_hz, scbr, bus_hz);
 723                 return -EINVAL;
 724         }
 725         csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
 726         csr = SPI_BFINS(SCBR, scbr, csr);
 727         spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 728
 729         return 0;
 730 }
 731
 732 /*
 733  * Submit next transfer for PDC.
 734  * lock is held, spi irq is blocked
 735  */
 736 static void atmel_spi_pdc_next_xfer(struct spi_master *master,
 737                                         struct spi_message *msg,
 738                                         struct spi_transfer *xfer)
 739 {
 740         struct atmel_spi        *as = spi_master_get_devdata(master);
 741         u32                     len;
 742         dma_addr_t              tx_dma, rx_dma;
 743
 744         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 745
 746         len = as->current_remaining_bytes;
 747         atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 748         as->current_remaining_bytes -= len;
 749
 750         spi_writel(as, RPR, rx_dma);
 751         spi_writel(as, TPR, tx_dma);
 752
 753         if (msg->spi->bits_per_word > 8)
 754                 len >>= 1;
 755         spi_writel(as, RCR, len);
 756         spi_writel(as, TCR, len);
 757
 758         dev_dbg(&msg->spi->dev,
 759                 "  start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 760                 xfer, xfer->len, xfer->tx_buf,
 761                 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
 762                 (unsigned long long)xfer->rx_dma);
 763
 764         if (as->current_remaining_bytes) {
 765                 len = as->current_remaining_bytes;
 766                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 767                 as->current_remaining_bytes -= len;
 768
 769                 spi_writel(as, RNPR, rx_dma);
 770                 spi_writel(as, TNPR, tx_dma);
 771
 772                 if (msg->spi->bits_per_word > 8)
 773                         len >>= 1;
 774                 spi_writel(as, RNCR, len);
 775                 spi_writel(as, TNCR, len);
 776
 777                 dev_dbg(&msg->spi->dev,
 778                         "  next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 779                         xfer, xfer->len, xfer->tx_buf,
 780                         (unsigned long long)xfer->tx_dma, xfer->rx_buf,
 781                         (unsigned long long)xfer->rx_dma);
 782         }
 783
 784         /* REVISIT: We're waiting for ENDRX before we start the next
 785          * transfer because we need to handle some difficult timing
 786          * issues otherwise. If we wait for ENDTX in one transfer and
 787          * then starts waiting for ENDRX in the next, it's difficult
 788          * to tell the difference between the ENDRX interrupt we're
 789          * actually waiting for and the ENDRX interrupt of the
 790          * previous transfer.
 791          *
 792          * It should be doable, though. Just not now...
 793          */
 794         spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
 795         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 796 }
 797
 798 /*
 799  * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
 800  *  - The buffer is either valid for CPU access, else NULL
 801  *  - If the buffer is valid, so is its DMA address
 802  *
 803  * This driver manages the dma address unless message->is_dma_mapped.
 804  */
 805 static int
 806 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 807 {
 808         struct device   *dev = &as->pdev->dev;
 809
 810         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 811         if (xfer->tx_buf) {
 812                 /* tx_buf is a const void* where we need a void * for the dma
 813                  * mapping */
 814                 void *nonconst_tx = (void *)xfer->tx_buf;
 815
 816                 xfer->tx_dma = dma_map_single(dev,
 817                                 nonconst_tx, xfer->len,
 818                                 DMA_TO_DEVICE);
 819                 if (dma_mapping_error(dev, xfer->tx_dma))
 820                         return -ENOMEM;
 821         }
 822         if (xfer->rx_buf) {
 823                 xfer->rx_dma = dma_map_single(dev,
 824                                 xfer->rx_buf, xfer->len,
 825                                 DMA_FROM_DEVICE);
 826                 if (dma_mapping_error(dev, xfer->rx_dma)) {
 827                         if (xfer->tx_buf)
 828                                 dma_unmap_single(dev,
 829                                                 xfer->tx_dma, xfer->len,
 830                                                 DMA_TO_DEVICE);
 831                         return -ENOMEM;
 832                 }
 833         }
 834         return 0;
 835 }
 836
 837 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
 838                                      struct spi_transfer *xfer)
 839 {
 840         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
 841                 dma_unmap_single(master->dev.parent, xfer->tx_dma,
 842                                  xfer->len, DMA_TO_DEVICE);
 843         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
 844                 dma_unmap_single(master->dev.parent, xfer->rx_dma,
 845                                  xfer->len, DMA_FROM_DEVICE);
 846 }
 847
 848 static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
 849 {
 850         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 851 }
 852
 853 /* Called from IRQ
 854  *
 855  * Must update "current_remaining_bytes" to keep track of data
 856  * to transfer.
 857  */
 858 static void
 859 atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
 860 {
 861         u8              *rxp;
 862         u16             *rxp16;
 863         unsigned long   xfer_pos = xfer->len - as->current_remaining_bytes;
 864
 865         if (xfer->rx_buf) {
 866                 if (xfer->bits_per_word > 8) {
 867                         rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
 868                         *rxp16 = spi_readl(as, RDR);
 869                 } else {
 870                         rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
 871                         *rxp = spi_readl(as, RDR);
 872                 }
 873         } else {
 874                 spi_readl(as, RDR);
 875         }
 876         if (xfer->bits_per_word > 8) {
 877                 as->current_remaining_bytes -= 2;
 878                 if (as->current_remaining_bytes < 0)
 879                         as->current_remaining_bytes = 0;
 880         } else {
 881                 as->current_remaining_bytes--;
 882         }
 883 }
 884
 885 /* Interrupt
 886  *
 887  * No need for locking in this Interrupt handler: done_status is the
 888  * only information modified.
 889  */
 890 static irqreturn_t
 891 atmel_spi_pio_interrupt(int irq, void *dev_id)
 892 {
 893         struct spi_master       *master = dev_id;
 894         struct atmel_spi        *as = spi_master_get_devdata(master);
 895         u32                     status, pending, imr;
 896         struct spi_transfer     *xfer;
 897         int                     ret = IRQ_NONE;
 898
 899         imr = spi_readl(as, IMR);
 900         status = spi_readl(as, SR);
 901         pending = status & imr;
 902
 903         if (pending & SPI_BIT(OVRES)) {
 904                 ret = IRQ_HANDLED;
 905                 spi_writel(as, IDR, SPI_BIT(OVRES));
 906                 dev_warn(master->dev.parent, "overrun\n");
 907
 908                 /*
 909                  * When we get an overrun, we disregard the current
 910                  * transfer. Data will not be copied back from any
 911                  * bounce buffer and msg->actual_len will not be
 912                  * updated with the last xfer.
 913                  *
 914                  * We will also not process any remaning transfers in
 915                  * the message.
 916                  */
 917                 as->done_status = -EIO;
 918                 smp_wmb();
 919
 920                 /* Clear any overrun happening while cleaning up */
 921                 spi_readl(as, SR);
 922
 923                 complete(&as->xfer_completion);
 924
 925         } else if (pending & SPI_BIT(RDRF)) {
 926                 atmel_spi_lock(as);
 927
 928                 if (as->current_remaining_bytes) {
 929                         ret = IRQ_HANDLED;
 930                         xfer = as->current_transfer;
 931                         atmel_spi_pump_pio_data(as, xfer);
 932                         if (!as->current_remaining_bytes)
 933                                 spi_writel(as, IDR, pending);
 934
 935                         complete(&as->xfer_completion);
 936                 }
 937
 938                 atmel_spi_unlock(as);
 939         } else {
 940                 WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
 941                 ret = IRQ_HANDLED;
 942                 spi_writel(as, IDR, pending);
 943         }
 944
 945         return ret;
 946 }
 947
 948 static irqreturn_t
 949 atmel_spi_pdc_interrupt(int irq, void *dev_id)
 950 {
 951         struct spi_master       *master = dev_id;
 952         struct atmel_spi        *as = spi_master_get_devdata(master);
 953         u32                     status, pending, imr;
 954         int                     ret = IRQ_NONE;
 955
 956         imr = spi_readl(as, IMR);
 957         status = spi_readl(as, SR);
 958         pending = status & imr;
 959
 960         if (pending & SPI_BIT(OVRES)) {
 961
 962                 ret = IRQ_HANDLED;
 963
 964                 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
 965                                      | SPI_BIT(OVRES)));
 966
 967                 /* Clear any overrun happening while cleaning up */
 968                 spi_readl(as, SR);
 969
 970                 as->done_status = -EIO;
 971
 972                 complete(&as->xfer_completion);
 973
 974         } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
 975                 ret = IRQ_HANDLED;
 976
 977                 spi_writel(as, IDR, pending);
 978
 979                 complete(&as->xfer_completion);
 980         }
 981
 982         return ret;
 983 }
 984
 985 static int atmel_spi_setup(struct spi_device *spi)
 986 {
 987         struct atmel_spi        *as;
 988         struct atmel_spi_device *asd;
 989         u32                     csr;
 990         unsigned int            bits = spi->bits_per_word;
 991         unsigned int            npcs_pin;
 992         int                     ret;
 993
 994         as = spi_master_get_devdata(spi->master);
 995
 996         if (spi->chip_select > spi->master->num_chipselect) {
 997                 dev_dbg(&spi->dev,
 998                                 "setup: invalid chipselect %u (%u defined)\n",
 999                                 spi->chip_select, spi->master->num_chipselect);
1000                 return -EINVAL;
1001         }
1002
1003         /* see notes above re chipselect */
1004         if (!atmel_spi_is_v2(as)
1005                         && spi->chip_select == 0
1006                         && (spi->mode & SPI_CS_HIGH)) {
1007                 dev_dbg(&spi->dev, "setup: can't be active-high\n");
1008                 return -EINVAL;
1009         }
1010
1011         csr = SPI_BF(BITS, bits - 8);
1012         if (spi->mode & SPI_CPOL)
1013                 csr |= SPI_BIT(CPOL);
1014         if (!(spi->mode & SPI_CPHA))
1015                 csr |= SPI_BIT(NCPHA);
1016
1017         /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
1018          *
1019          * DLYBCT would add delays between words, slowing down transfers.
1020          * It could potentially be useful to cope with DMA bottlenecks, but
1021          * in those cases it's probably best to just use a lower bitrate.
1022          */
1023         csr |= SPI_BF(DLYBS, 0);
1024         csr |= SPI_BF(DLYBCT, 0);
1025
1026         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
1027         npcs_pin = (unsigned int)spi->controller_data;
1028
1029         if (gpio_is_valid(spi->cs_gpio))
1030                 npcs_pin = spi->cs_gpio;
1031
1032         asd = spi->controller_state;
1033         if (!asd) {
1034                 asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
1035                 if (!asd)
1036                         return -ENOMEM;
1037
1038                 ret = gpio_request(npcs_pin, dev_name(&spi->dev));
1039                 if (ret) {
1040                         kfree(asd);
1041                         return ret;
1042                 }
1043
1044                 asd->npcs_pin = npcs_pin;
1045                 spi->controller_state = asd;
1046                 gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
1047         }
1048
1049         asd->csr = csr;
1050
1051         dev_dbg(&spi->dev,
1052                 "setup: bpw %u mode 0x%x -> csr%d %08x\n",
1053                 bits, spi->mode, spi->chip_select, csr);
1054
1055         if (!atmel_spi_is_v2(as))
1056                 spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
1057
1058         return 0;
1059 }
1060
1061 static int atmel_spi_one_transfer(struct spi_master *master,
1062                                         struct spi_message *msg,
1063                                         struct spi_transfer *xfer)
1064 {
1065         struct atmel_spi        *as;
1066         struct spi_device       *spi = msg->spi;
1067         u8                      bits;
1068         u32                     len;
1069         struct atmel_spi_device *asd;
1070         int                     timeout;
1071         int                     ret;
1072
1073         as = spi_master_get_devdata(master);
1074
1075         if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1076                 dev_dbg(&spi->dev, "missing rx or tx buf\n");
1077                 return -EINVAL;
1078         }
1079
1080         if (xfer->bits_per_word) {
1081                 asd = spi->controller_state;
1082                 bits = (asd->csr >> 4) & 0xf;
1083                 if (bits != xfer->bits_per_word - 8) {
1084                         dev_dbg(&spi->dev,
1085                         "you can't yet change bits_per_word in transfers\n");
1086                         return -ENOPROTOOPT;
1087                 }
1088         }
1089
1090         if (xfer->bits_per_word > 8) {
1091                 if (xfer->len % 2) {
1092                         dev_dbg(&spi->dev,
1093                         "buffer len should be 16 bits aligned\n");
1094                         return -EINVAL;
1095                 }
1096         }
1097
1098         /*
1099          * DMA map early, for performance (empties dcache ASAP) and
1100          * better fault reporting.
1101          */
1102         if ((!msg->is_dma_mapped)
1103                 && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) {
1104                 if (atmel_spi_dma_map_xfer(as, xfer) < 0)
1105                         return -ENOMEM;
1106         }
1107
1108         atmel_spi_set_xfer_speed(as, msg->spi, xfer);
1109
1110         as->done_status = 0;
1111         as->current_transfer = xfer;
1112         as->current_remaining_bytes = xfer->len;
1113         while (as->current_remaining_bytes) {
1114                 reinit_completion(&as->xfer_completion);
1115
1116                 if (as->use_pdc) {
1117                         atmel_spi_pdc_next_xfer(master, msg, xfer);
1118                 } else if (atmel_spi_use_dma(as, xfer)) {
1119                         len = as->current_remaining_bytes;
1120                         ret = atmel_spi_next_xfer_dma_submit(master,
1121                                                                 xfer, &len);
1122                         if (ret) {
1123                                 dev_err(&spi->dev,
1124                                         "unable to use DMA, fallback to PIO\n");
1125                                 atmel_spi_next_xfer_pio(master, xfer);
1126                         } else {
1127                                 as->current_remaining_bytes -= len;
1128                         }
1129                 } else {
1130                         atmel_spi_next_xfer_pio(master, xfer);
1131                 }
1132
1133                 ret = wait_for_completion_timeout(&as->xfer_completion,
1134                                                         SPI_DMA_TIMEOUT);
1135                 if (WARN_ON(ret == 0)) {
1136                         dev_err(&spi->dev,
1137                                 "spi trasfer timeout, err %d\n", ret);
1138                         as->done_status = -EIO;
1139                 } else {
1140                         ret = 0;
1141                 }
1142
1143                 if (as->done_status)
1144                         break;
1145         }
1146
1147         if (as->done_status) {
1148                 if (as->use_pdc) {
1149                         dev_warn(master->dev.parent,
1150                                 "overrun (%u/%u remaining)\n",
1151                                 spi_readl(as, TCR), spi_readl(as, RCR));
1152
1153                         /*
1154                          * Clean up DMA registers and make sure the data
1155                          * registers are empty.
1156                          */
1157                         spi_writel(as, RNCR, 0);
1158                         spi_writel(as, TNCR, 0);
1159                         spi_writel(as, RCR, 0);
1160                         spi_writel(as, TCR, 0);
1161                         for (timeout = 1000; timeout; timeout--)
1162                                 if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
1163                                         break;
1164                         if (!timeout)
1165                                 dev_warn(master->dev.parent,
1166                                          "timeout waiting for TXEMPTY");
1167                         while (spi_readl(as, SR) & SPI_BIT(RDRF))
1168                                 spi_readl(as, RDR);
1169
1170                         /* Clear any overrun happening while cleaning up */
1171                         spi_readl(as, SR);
1172
1173                 } else if (atmel_spi_use_dma(as, xfer)) {
1174                         atmel_spi_stop_dma(as);
1175                 }
1176
1177                 if (!msg->is_dma_mapped
1178                         && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1179                         atmel_spi_dma_unmap_xfer(master, xfer);
1180
1181                 return 0;
1182
1183         } else {
1184                 /* only update length if no error */
1185                 msg->actual_length += xfer->len;
1186         }
1187
1188         if (!msg->is_dma_mapped
1189                 && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1190                 atmel_spi_dma_unmap_xfer(master, xfer);
1191
1192         if (xfer->delay_usecs)
1193                 udelay(xfer->delay_usecs);
1194
1195         if (xfer->cs_change) {
1196                 if (list_is_last(&xfer->transfer_list,
1197                                  &msg->transfers)) {
1198                         as->keep_cs = true;
1199                 } else {
1200                         as->cs_active = !as->cs_active;
1201                         if (as->cs_active)
1202                                 cs_activate(as, msg->spi);
1203                         else
1204                                 cs_deactivate(as, msg->spi);
1205                 }
1206         }
1207
1208         return 0;
1209 }
1210
1211 static int atmel_spi_transfer_one_message(struct spi_master *master,
1212                                                 struct spi_message *msg)
1213 {
1214         struct atmel_spi *as;
1215         struct spi_transfer *xfer;
1216         struct spi_device *spi = msg->spi;
1217         int ret = 0;
1218
1219         as = spi_master_get_devdata(master);
1220
1221         dev_dbg(&spi->dev, "new message %p submitted for %s\n",
1222                                         msg, dev_name(&spi->dev));
1223
1224         if (unlikely(list_empty(&msg->transfers)))
1225                 return -EINVAL;
1226
1227         atmel_spi_lock(as);
1228         cs_activate(as, spi);
1229
1230         as->cs_active = true;
1231         as->keep_cs = false;
1232
1233         msg->status = 0;
1234         msg->actual_length = 0;
1235
1236         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1237                 ret = atmel_spi_one_transfer(master, msg, xfer);
1238                 if (ret)
1239                         goto msg_done;
1240         }
1241
1242         if (as->use_pdc)
1243                 atmel_spi_disable_pdc_transfer(as);
1244
1245         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1246                 dev_dbg(&spi->dev,
1247                         "  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
1248                         xfer, xfer->len,
1249                         xfer->tx_buf, xfer->tx_dma,
1250                         xfer->rx_buf, xfer->rx_dma);
1251         }
1252
1253 msg_done:
1254         if (!as->keep_cs)
1255                 cs_deactivate(as, msg->spi);
1256
1257         atmel_spi_unlock(as);
1258
1259         msg->status = as->done_status;
1260         spi_finalize_current_message(spi->master);
1261
1262         return ret;
1263 }
1264
1265 static void atmel_spi_cleanup(struct spi_device *spi)
1266 {
1267         struct atmel_spi_device *asd = spi->controller_state;
1268         unsigned                gpio = (unsigned) spi->controller_data;
1269
1270         if (!asd)
1271                 return;
1272
1273         spi->controller_state = NULL;
1274         gpio_free(gpio);
1275         kfree(asd);
1276 }
1277
1278 static inline unsigned int atmel_get_version(struct atmel_spi *as)
1279 {
1280         return spi_readl(as, VERSION) & 0x00000fff;
1281 }
1282
1283 static void atmel_get_caps(struct atmel_spi *as)
1284 {
1285         unsigned int version;
1286
1287         version = atmel_get_version(as);
1288         dev_info(&as->pdev->dev, "version: 0x%x\n", version);
1289
1290         as->caps.is_spi2 = version > 0x121;
1291         as->caps.has_wdrbt = version >= 0x210;
1292         as->caps.has_dma_support = version >= 0x212;
1293 }
1294
1295 /*-------------------------------------------------------------------------*/
1296
1297 static int atmel_spi_probe(struct platform_device *pdev)
1298 {
1299         struct resource         *regs;
1300         int                     irq;
1301         struct clk              *clk;
1302         int                     ret;
1303         struct spi_master       *master;
1304         struct atmel_spi        *as;
1305
1306         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1307         if (!regs)
1308                 return -ENXIO;
1309
1310         irq = platform_get_irq(pdev, 0);
1311         if (irq < 0)
1312                 return irq;
1313
1314         clk = devm_clk_get(&pdev->dev, "spi_clk");
1315         if (IS_ERR(clk))
1316                 return PTR_ERR(clk);
1317
1318         /* setup spi core then atmel-specific driver state */
1319         ret = -ENOMEM;
1320         master = spi_alloc_master(&pdev->dev, sizeof(*as));
1321         if (!master)
1322                 goto out_free;
1323
1324         /* the spi->mode bits understood by this driver: */
1325         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1326         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
1327         master->dev.of_node = pdev->dev.of_node;
1328         master->bus_num = pdev->id;
1329         master->num_chipselect = master->dev.of_node ? 0 : 4;
1330         master->setup = atmel_spi_setup;
1331         master->transfer_one_message = atmel_spi_transfer_one_message;
1332         master->cleanup = atmel_spi_cleanup;
1333         platform_set_drvdata(pdev, master);
1334
1335         as = spi_master_get_devdata(master);
1336
1337         /*
1338          * Scratch buffer is used for throwaway rx and tx data.
1339          * It's coherent to minimize dcache pollution.
1340          */
1341         as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
1342                                         &as->buffer_dma, GFP_KERNEL);
1343         if (!as->buffer)
1344                 goto out_free;
1345
1346         spin_lock_init(&as->lock);
1347
1348         as->pdev = pdev;
1349         as->regs = devm_ioremap_resource(&pdev->dev, regs);
1350         if (IS_ERR(as->regs)) {
1351                 ret = PTR_ERR(as->regs);
1352                 goto out_free_buffer;
1353         }
1354         as->phybase = regs->start;
1355         as->irq = irq;
1356         as->clk = clk;
1357
1358         init_completion(&as->xfer_completion);
1359
1360         atmel_get_caps(as);
1361
1362         as->use_dma = false;
1363         as->use_pdc = false;
1364         if (as->caps.has_dma_support) {
1365                 if (atmel_spi_configure_dma(as) == 0)
1366                         as->use_dma = true;
1367         } else {
1368                 as->use_pdc = true;
1369         }
1370
1371         if (as->caps.has_dma_support && !as->use_dma)
1372                 dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
1373
1374         if (as->use_pdc) {
1375                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
1376                                         0, dev_name(&pdev->dev), master);
1377         } else {
1378                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
1379                                         0, dev_name(&pdev->dev), master);
1380         }
1381         if (ret)
1382                 goto out_unmap_regs;
1383
1384         /* Initialize the hardware */
1385         ret = clk_prepare_enable(clk);
1386         if (ret)
1387                 goto out_free_irq;
1388         spi_writel(as, CR, SPI_BIT(SWRST));
1389         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1390         if (as->caps.has_wdrbt) {
1391                 spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
1392                                 | SPI_BIT(MSTR));
1393         } else {
1394                 spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
1395         }
1396
1397         if (as->use_pdc)
1398                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1399         spi_writel(as, CR, SPI_BIT(SPIEN));
1400
1401         /* go! */
1402         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
1403                         (unsigned long)regs->start, irq);
1404
1405         ret = devm_spi_register_master(&pdev->dev, master);
1406         if (ret)
1407                 goto out_free_dma;
1408
1409         return 0;
1410
1411 out_free_dma:
1412         if (as->use_dma)
1413                 atmel_spi_release_dma(as);
1414
1415         spi_writel(as, CR, SPI_BIT(SWRST));
1416         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1417         clk_disable_unprepare(clk);
1418 out_free_irq:
1419 out_unmap_regs:
1420 out_free_buffer:
1421         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1422                         as->buffer_dma);
1423 out_free:
1424         spi_master_put(master);
1425         return ret;
1426 }
1427
1428 static int atmel_spi_remove(struct platform_device *pdev)
1429 {
1430         struct spi_master       *master = platform_get_drvdata(pdev);
1431         struct atmel_spi        *as = spi_master_get_devdata(master);
1432
1433         /* reset the hardware and block queue progress */
1434         spin_lock_irq(&as->lock);
1435         if (as->use_dma) {
1436                 atmel_spi_stop_dma(as);
1437                 atmel_spi_release_dma(as);
1438         }
1439
1440         spi_writel(as, CR, SPI_BIT(SWRST));
1441         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1442         spi_readl(as, SR);
1443         spin_unlock_irq(&as->lock);
1444
1445         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1446                         as->buffer_dma);
1447
1448         clk_disable_unprepare(as->clk);
1449
1450         return 0;
1451 }
1452
1453 #ifdef CONFIG_PM_SLEEP
1454 static int atmel_spi_suspend(struct device *dev)
1455 {
1456         struct spi_master       *master = dev_get_drvdata(dev);
1457         struct atmel_spi        *as = spi_master_get_devdata(master);
1458
1459         clk_disable_unprepare(as->clk);
1460         return 0;
1461 }
1462
1463 static int atmel_spi_resume(struct device *dev)
1464 {
1465         struct spi_master       *master = dev_get_drvdata(dev);
1466         struct atmel_spi        *as = spi_master_get_devdata(master);
1467
1468         clk_prepare_enable(as->clk);
1469         return 0;
1470 }
1471
1472 static SIMPLE_DEV_PM_OPS(atmel_spi_pm_ops, atmel_spi_suspend, atmel_spi_resume);
1473
1474 #define ATMEL_SPI_PM_OPS        (&atmel_spi_pm_ops)
1475 #else
1476 #define ATMEL_SPI_PM_OPS        NULL
1477 #endif
1478
1479 #if defined(CONFIG_OF)
1480 static const struct of_device_id atmel_spi_dt_ids[] = {
1481         { .compatible = "atmel,at91rm9200-spi" },
1482         { /* sentinel */ }
1483 };
1484
1485 MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
1486 #endif
1487
1488 static struct platform_driver atmel_spi_driver = {
1489         .driver         = {
1490                 .name   = "atmel_spi",
1491                 .owner  = THIS_MODULE,
1492                 .pm     = ATMEL_SPI_PM_OPS,
1493                 .of_match_table = of_match_ptr(atmel_spi_dt_ids),
1494         },
1495         .probe          = atmel_spi_probe,
1496         .remove         = atmel_spi_remove,
1497 };
1498 module_platform_driver(atmel_spi_driver);
1499
1500 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
1501 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1502 MODULE_LICENSE("GPL");
1503 MODULE_ALIAS("platform:atmel_spi");