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/clk.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/delay.h>
  16 #include <linux/dma-mapping.h>
  17 #include <linux/dmaengine.h>
  18 #include <linux/err.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/spi/spi.h>
  21 #include <linux/slab.h>
  22 #include <linux/platform_data/dma-atmel.h>
  23 #include <linux/of.h>
  24
  25 #include <linux/io.h>
  26 #include <linux/gpio.h>
  27 #include <linux/pinctrl/consumer.h>
  28 #include <linux/pm_runtime.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_FMR                                 0x0040
  44 #define SPI_FLR                                 0x0044
  45 #define SPI_VERSION                             0x00fc
  46 #define SPI_RPR                                 0x0100
  47 #define SPI_RCR                                 0x0104
  48 #define SPI_TPR                                 0x0108
  49 #define SPI_TCR                                 0x010c
  50 #define SPI_RNPR                                0x0110
  51 #define SPI_RNCR                                0x0114
  52 #define SPI_TNPR                                0x0118
  53 #define SPI_TNCR                                0x011c
  54 #define SPI_PTCR                                0x0120
  55 #define SPI_PTSR                                0x0124
  56
  57 /* Bitfields in CR */
  58 #define SPI_SPIEN_OFFSET                        0
  59 #define SPI_SPIEN_SIZE                          1
  60 #define SPI_SPIDIS_OFFSET                       1
  61 #define SPI_SPIDIS_SIZE                         1
  62 #define SPI_SWRST_OFFSET                        7
  63 #define SPI_SWRST_SIZE                          1
  64 #define SPI_LASTXFER_OFFSET                     24
  65 #define SPI_LASTXFER_SIZE                       1
  66 #define SPI_TXFCLR_OFFSET                       16
  67 #define SPI_TXFCLR_SIZE                         1
  68 #define SPI_RXFCLR_OFFSET                       17
  69 #define SPI_RXFCLR_SIZE                         1
  70 #define SPI_FIFOEN_OFFSET                       30
  71 #define SPI_FIFOEN_SIZE                         1
  72 #define SPI_FIFODIS_OFFSET                      31
  73 #define SPI_FIFODIS_SIZE                        1
  74
  75 /* Bitfields in MR */
  76 #define SPI_MSTR_OFFSET                         0
  77 #define SPI_MSTR_SIZE                           1
  78 #define SPI_PS_OFFSET                           1
  79 #define SPI_PS_SIZE                             1
  80 #define SPI_PCSDEC_OFFSET                       2
  81 #define SPI_PCSDEC_SIZE                         1
  82 #define SPI_FDIV_OFFSET                         3
  83 #define SPI_FDIV_SIZE                           1
  84 #define SPI_MODFDIS_OFFSET                      4
  85 #define SPI_MODFDIS_SIZE                        1
  86 #define SPI_WDRBT_OFFSET                        5
  87 #define SPI_WDRBT_SIZE                          1
  88 #define SPI_LLB_OFFSET                          7
  89 #define SPI_LLB_SIZE                            1
  90 #define SPI_PCS_OFFSET                          16
  91 #define SPI_PCS_SIZE                            4
  92 #define SPI_DLYBCS_OFFSET                       24
  93 #define SPI_DLYBCS_SIZE                         8
  94
  95 /* Bitfields in RDR */
  96 #define SPI_RD_OFFSET                           0
  97 #define SPI_RD_SIZE                             16
  98
  99 /* Bitfields in TDR */
 100 #define SPI_TD_OFFSET                           0
 101 #define SPI_TD_SIZE                             16
 102
 103 /* Bitfields in SR */
 104 #define SPI_RDRF_OFFSET                         0
 105 #define SPI_RDRF_SIZE                           1
 106 #define SPI_TDRE_OFFSET                         1
 107 #define SPI_TDRE_SIZE                           1
 108 #define SPI_MODF_OFFSET                         2
 109 #define SPI_MODF_SIZE                           1
 110 #define SPI_OVRES_OFFSET                        3
 111 #define SPI_OVRES_SIZE                          1
 112 #define SPI_ENDRX_OFFSET                        4
 113 #define SPI_ENDRX_SIZE                          1
 114 #define SPI_ENDTX_OFFSET                        5
 115 #define SPI_ENDTX_SIZE                          1
 116 #define SPI_RXBUFF_OFFSET                       6
 117 #define SPI_RXBUFF_SIZE                         1
 118 #define SPI_TXBUFE_OFFSET                       7
 119 #define SPI_TXBUFE_SIZE                         1
 120 #define SPI_NSSR_OFFSET                         8
 121 #define SPI_NSSR_SIZE                           1
 122 #define SPI_TXEMPTY_OFFSET                      9
 123 #define SPI_TXEMPTY_SIZE                        1
 124 #define SPI_SPIENS_OFFSET                       16
 125 #define SPI_SPIENS_SIZE                         1
 126 #define SPI_TXFEF_OFFSET                        24
 127 #define SPI_TXFEF_SIZE                          1
 128 #define SPI_TXFFF_OFFSET                        25
 129 #define SPI_TXFFF_SIZE                          1
 130 #define SPI_TXFTHF_OFFSET                       26
 131 #define SPI_TXFTHF_SIZE                         1
 132 #define SPI_RXFEF_OFFSET                        27
 133 #define SPI_RXFEF_SIZE                          1
 134 #define SPI_RXFFF_OFFSET                        28
 135 #define SPI_RXFFF_SIZE                          1
 136 #define SPI_RXFTHF_OFFSET                       29
 137 #define SPI_RXFTHF_SIZE                         1
 138 #define SPI_TXFPTEF_OFFSET                      30
 139 #define SPI_TXFPTEF_SIZE                        1
 140 #define SPI_RXFPTEF_OFFSET                      31
 141 #define SPI_RXFPTEF_SIZE                        1
 142
 143 /* Bitfields in CSR0 */
 144 #define SPI_CPOL_OFFSET                         0
 145 #define SPI_CPOL_SIZE                           1
 146 #define SPI_NCPHA_OFFSET                        1
 147 #define SPI_NCPHA_SIZE                          1
 148 #define SPI_CSAAT_OFFSET                        3
 149 #define SPI_CSAAT_SIZE                          1
 150 #define SPI_BITS_OFFSET                         4
 151 #define SPI_BITS_SIZE                           4
 152 #define SPI_SCBR_OFFSET                         8
 153 #define SPI_SCBR_SIZE                           8
 154 #define SPI_DLYBS_OFFSET                        16
 155 #define SPI_DLYBS_SIZE                          8
 156 #define SPI_DLYBCT_OFFSET                       24
 157 #define SPI_DLYBCT_SIZE                         8
 158
 159 /* Bitfields in RCR */
 160 #define SPI_RXCTR_OFFSET                        0
 161 #define SPI_RXCTR_SIZE                          16
 162
 163 /* Bitfields in TCR */
 164 #define SPI_TXCTR_OFFSET                        0
 165 #define SPI_TXCTR_SIZE                          16
 166
 167 /* Bitfields in RNCR */
 168 #define SPI_RXNCR_OFFSET                        0
 169 #define SPI_RXNCR_SIZE                          16
 170
 171 /* Bitfields in TNCR */
 172 #define SPI_TXNCR_OFFSET                        0
 173 #define SPI_TXNCR_SIZE                          16
 174
 175 /* Bitfields in PTCR */
 176 #define SPI_RXTEN_OFFSET                        0
 177 #define SPI_RXTEN_SIZE                          1
 178 #define SPI_RXTDIS_OFFSET                       1
 179 #define SPI_RXTDIS_SIZE                         1
 180 #define SPI_TXTEN_OFFSET                        8
 181 #define SPI_TXTEN_SIZE                          1
 182 #define SPI_TXTDIS_OFFSET                       9
 183 #define SPI_TXTDIS_SIZE                         1
 184
 185 /* Bitfields in FMR */
 186 #define SPI_TXRDYM_OFFSET                       0
 187 #define SPI_TXRDYM_SIZE                         2
 188 #define SPI_RXRDYM_OFFSET                       4
 189 #define SPI_RXRDYM_SIZE                         2
 190 #define SPI_TXFTHRES_OFFSET                     16
 191 #define SPI_TXFTHRES_SIZE                       6
 192 #define SPI_RXFTHRES_OFFSET                     24
 193 #define SPI_RXFTHRES_SIZE                       6
 194
 195 /* Bitfields in FLR */
 196 #define SPI_TXFL_OFFSET                         0
 197 #define SPI_TXFL_SIZE                           6
 198 #define SPI_RXFL_OFFSET                         16
 199 #define SPI_RXFL_SIZE                           6
 200
 201 /* Constants for BITS */
 202 #define SPI_BITS_8_BPT                          0
 203 #define SPI_BITS_9_BPT                          1
 204 #define SPI_BITS_10_BPT                         2
 205 #define SPI_BITS_11_BPT                         3
 206 #define SPI_BITS_12_BPT                         4
 207 #define SPI_BITS_13_BPT                         5
 208 #define SPI_BITS_14_BPT                         6
 209 #define SPI_BITS_15_BPT                         7
 210 #define SPI_BITS_16_BPT                         8
 211 #define SPI_ONE_DATA                            0
 212 #define SPI_TWO_DATA                            1
 213 #define SPI_FOUR_DATA                           2
 214
 215 /* Bit manipulation macros */
 216 #define SPI_BIT(name) \
 217         (1 << SPI_##name##_OFFSET)
 218 #define SPI_BF(name, value) \
 219         (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
 220 #define SPI_BFEXT(name, value) \
 221         (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
 222 #define SPI_BFINS(name, value, old) \
 223         (((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
 224           | SPI_BF(name, value))
 225
 226 /* Register access macros */
 227 #ifdef CONFIG_AVR32
 228 #define spi_readl(port, reg) \
 229         __raw_readl((port)->regs + SPI_##reg)
 230 #define spi_writel(port, reg, value) \
 231         __raw_writel((value), (port)->regs + SPI_##reg)
 232
 233 #define spi_readw(port, reg) \
 234         __raw_readw((port)->regs + SPI_##reg)
 235 #define spi_writew(port, reg, value) \
 236         __raw_writew((value), (port)->regs + SPI_##reg)
 237
 238 #define spi_readb(port, reg) \
 239         __raw_readb((port)->regs + SPI_##reg)
 240 #define spi_writeb(port, reg, value) \
 241         __raw_writeb((value), (port)->regs + SPI_##reg)
 242 #else
 243 #define spi_readl(port, reg) \
 244         readl_relaxed((port)->regs + SPI_##reg)
 245 #define spi_writel(port, reg, value) \
 246         writel_relaxed((value), (port)->regs + SPI_##reg)
 247
 248 #define spi_readw(port, reg) \
 249         readw_relaxed((port)->regs + SPI_##reg)
 250 #define spi_writew(port, reg, value) \
 251         writew_relaxed((value), (port)->regs + SPI_##reg)
 252
 253 #define spi_readb(port, reg) \
 254         readb_relaxed((port)->regs + SPI_##reg)
 255 #define spi_writeb(port, reg, value) \
 256         writeb_relaxed((value), (port)->regs + SPI_##reg)
 257 #endif
 258 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
 259  * cache operations; better heuristics consider wordsize and bitrate.
 260  */
 261 #define DMA_MIN_BYTES   16
 262
 263 #define SPI_DMA_TIMEOUT         (msecs_to_jiffies(1000))
 264
 265 #define AUTOSUSPEND_TIMEOUT     2000
 266
 267 struct atmel_spi_dma {
 268         struct dma_chan                 *chan_rx;
 269         struct dma_chan                 *chan_tx;
 270         struct scatterlist              sgrx;
 271         struct scatterlist              sgtx;
 272         struct dma_async_tx_descriptor  *data_desc_rx;
 273         struct dma_async_tx_descriptor  *data_desc_tx;
 274
 275         struct at_dma_slave     dma_slave;
 276 };
 277
 278 struct atmel_spi_caps {
 279         bool    is_spi2;
 280         bool    has_wdrbt;
 281         bool    has_dma_support;
 282 };
 283
 284 /*
 285  * The core SPI transfer engine just talks to a register bank to set up
 286  * DMA transfers; transfer queue progress is driven by IRQs.  The clock
 287  * framework provides the base clock, subdivided for each spi_device.
 288  */
 289 struct atmel_spi {
 290         spinlock_t              lock;
 291         unsigned long           flags;
 292
 293         phys_addr_t             phybase;
 294         void __iomem            *regs;
 295         int                     irq;
 296         struct clk              *clk;
 297         struct platform_device  *pdev;
 298
 299         struct spi_transfer     *current_transfer;
 300         int                     current_remaining_bytes;
 301         int                     done_status;
 302
 303         struct completion       xfer_completion;
 304
 305         /* scratch buffer */
 306         void                    *buffer;
 307         dma_addr_t              buffer_dma;
 308
 309         struct atmel_spi_caps   caps;
 310
 311         bool                    use_dma;
 312         bool                    use_pdc;
 313         bool                    use_cs_gpios;
 314         /* dmaengine data */
 315         struct atmel_spi_dma    dma;
 316
 317         bool                    keep_cs;
 318         bool                    cs_active;
 319
 320         u32                     fifo_size;
 321 };
 322
 323 /* Controller-specific per-slave state */
 324 struct atmel_spi_device {
 325         unsigned int            npcs_pin;
 326         u32                     csr;
 327 };
 328
 329 #define BUFFER_SIZE             PAGE_SIZE
 330 #define INVALID_DMA_ADDRESS     0xffffffff
 331
 332 /*
 333  * Version 2 of the SPI controller has
 334  *  - CR.LASTXFER
 335  *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
 336  *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
 337  *  - SPI_CSRx.CSAAT
 338  *  - SPI_CSRx.SBCR allows faster clocking
 339  */
 340 static bool atmel_spi_is_v2(struct atmel_spi *as)
 341 {
 342         return as->caps.is_spi2;
 343 }
 344
 345 /*
 346  * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
 347  * they assume that spi slave device state will not change on deselect, so
 348  * that automagic deselection is OK.  ("NPCSx rises if no data is to be
 349  * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
 350  * controllers have CSAAT and friends.
 351  *
 352  * Since the CSAAT functionality is a bit weird on newer controllers as
 353  * well, we use GPIO to control nCSx pins on all controllers, updating
 354  * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
 355  * support active-high chipselects despite the controller's belief that
 356  * only active-low devices/systems exists.
 357  *
 358  * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
 359  * right when driven with GPIO.  ("Mode Fault does not allow more than one
 360  * Master on Chip Select 0.")  No workaround exists for that ... so for
 361  * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
 362  * and (c) will trigger that first erratum in some cases.
 363  */
 364
 365 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 366 {
 367         struct atmel_spi_device *asd = spi->controller_state;
 368         unsigned active = spi->mode & SPI_CS_HIGH;
 369         u32 mr;
 370
 371         if (atmel_spi_is_v2(as)) {
 372                 spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
 373                 /* For the low SPI version, there is a issue that PDC transfer
 374                  * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
 375                  */
 376                 spi_writel(as, CSR0, asd->csr);
 377                 if (as->caps.has_wdrbt) {
 378                         spi_writel(as, MR,
 379                                         SPI_BF(PCS, ~(0x01 << spi->chip_select))
 380                                         | SPI_BIT(WDRBT)
 381                                         | SPI_BIT(MODFDIS)
 382                                         | SPI_BIT(MSTR));
 383                 } else {
 384                         spi_writel(as, MR,
 385                                         SPI_BF(PCS, ~(0x01 << spi->chip_select))
 386                                         | SPI_BIT(MODFDIS)
 387                                         | SPI_BIT(MSTR));
 388                 }
 389
 390                 mr = spi_readl(as, MR);
 391                 if (as->use_cs_gpios)
 392                         gpio_set_value(asd->npcs_pin, active);
 393         } else {
 394                 u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
 395                 int i;
 396                 u32 csr;
 397
 398                 /* Make sure clock polarity is correct */
 399                 for (i = 0; i < spi->master->num_chipselect; i++) {
 400                         csr = spi_readl(as, CSR0 + 4 * i);
 401                         if ((csr ^ cpol) & SPI_BIT(CPOL))
 402                                 spi_writel(as, CSR0 + 4 * i,
 403                                                 csr ^ SPI_BIT(CPOL));
 404                 }
 405
 406                 mr = spi_readl(as, MR);
 407                 mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
 408                 if (as->use_cs_gpios && spi->chip_select != 0)
 409                         gpio_set_value(asd->npcs_pin, active);
 410                 spi_writel(as, MR, mr);
 411         }
 412
 413         dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
 414                         asd->npcs_pin, active ? " (high)" : "",
 415                         mr);
 416 }
 417
 418 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 419 {
 420         struct atmel_spi_device *asd = spi->controller_state;
 421         unsigned active = spi->mode & SPI_CS_HIGH;
 422         u32 mr;
 423
 424         /* only deactivate *this* device; sometimes transfers to
 425          * another device may be active when this routine is called.
 426          */
 427         mr = spi_readl(as, MR);
 428         if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
 429                 mr = SPI_BFINS(PCS, 0xf, mr);
 430                 spi_writel(as, MR, mr);
 431         }
 432
 433         dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
 434                         asd->npcs_pin, active ? " (low)" : "",
 435                         mr);
 436
 437         if (!as->use_cs_gpios)
 438                 spi_writel(as, CR, SPI_BIT(LASTXFER));
 439         else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
 440                 gpio_set_value(asd->npcs_pin, !active);
 441 }
 442
 443 static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
 444 {
 445         spin_lock_irqsave(&as->lock, as->flags);
 446 }
 447
 448 static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock)
 449 {
 450         spin_unlock_irqrestore(&as->lock, as->flags);
 451 }
 452
 453 static inline bool atmel_spi_use_dma(struct atmel_spi *as,
 454                                 struct spi_transfer *xfer)
 455 {
 456         return as->use_dma && xfer->len >= DMA_MIN_BYTES;
 457 }
 458
 459 static int atmel_spi_dma_slave_config(struct atmel_spi *as,
 460                                 struct dma_slave_config *slave_config,
 461                                 u8 bits_per_word)
 462 {
 463         int err = 0;
 464
 465         if (bits_per_word > 8) {
 466                 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 467                 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 468         } else {
 469                 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 470                 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 471         }
 472
 473         slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
 474         slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR;
 475         slave_config->src_maxburst = 1;
 476         slave_config->dst_maxburst = 1;
 477         slave_config->device_fc = false;
 478
 479         /*
 480          * This driver uses fixed peripheral select mode (PS bit set to '0' in
 481          * the Mode Register).
 482          * So according to the datasheet, when FIFOs are available (and
 483          * enabled), the Transmit FIFO operates in Multiple Data Mode.
 484          * In this mode, up to 2 data, not 4, can be written into the Transmit
 485          * Data Register in a single access.
 486          * However, the first data has to be written into the lowest 16 bits and
 487          * the second data into the highest 16 bits of the Transmit
 488          * Data Register. For 8bit data (the most frequent case), it would
 489          * require to rework tx_buf so each data would actualy fit 16 bits.
 490          * So we'd rather write only one data at the time. Hence the transmit
 491          * path works the same whether FIFOs are available (and enabled) or not.
 492          */
 493         slave_config->direction = DMA_MEM_TO_DEV;
 494         if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) {
 495                 dev_err(&as->pdev->dev,
 496                         "failed to configure tx dma channel\n");
 497                 err = -EINVAL;
 498         }
 499
 500         /*
 501          * This driver configures the spi controller for master mode (MSTR bit
 502          * set to '1' in the Mode Register).
 503          * So according to the datasheet, when FIFOs are available (and
 504          * enabled), the Receive FIFO operates in Single Data Mode.
 505          * So the receive path works the same whether FIFOs are available (and
 506          * enabled) or not.
 507          */
 508         slave_config->direction = DMA_DEV_TO_MEM;
 509         if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) {
 510                 dev_err(&as->pdev->dev,
 511                         "failed to configure rx dma channel\n");
 512                 err = -EINVAL;
 513         }
 514
 515         return err;
 516 }
 517
 518 static int atmel_spi_configure_dma(struct atmel_spi *as)
 519 {
 520         struct dma_slave_config slave_config;
 521         struct device *dev = &as->pdev->dev;
 522         int err;
 523
 524         dma_cap_mask_t mask;
 525         dma_cap_zero(mask);
 526         dma_cap_set(DMA_SLAVE, mask);
 527
 528         as->dma.chan_tx = dma_request_slave_channel_reason(dev, "tx");
 529         if (IS_ERR(as->dma.chan_tx)) {
 530                 err = PTR_ERR(as->dma.chan_tx);
 531                 if (err == -EPROBE_DEFER) {
 532                         dev_warn(dev, "no DMA channel available at the moment\n");
 533                         return err;
 534                 }
 535                 dev_err(dev,
 536                         "DMA TX channel not available, SPI unable to use DMA\n");
 537                 err = -EBUSY;
 538                 goto error;
 539         }
 540
 541         /*
 542          * No reason to check EPROBE_DEFER here since we have already requested
 543          * tx channel. If it fails here, it's for another reason.
 544          */
 545         as->dma.chan_rx = dma_request_slave_channel(dev, "rx");
 546
 547         if (!as->dma.chan_rx) {
 548                 dev_err(dev,
 549                         "DMA RX channel not available, SPI unable to use DMA\n");
 550                 err = -EBUSY;
 551                 goto error;
 552         }
 553
 554         err = atmel_spi_dma_slave_config(as, &slave_config, 8);
 555         if (err)
 556                 goto error;
 557
 558         dev_info(&as->pdev->dev,
 559                         "Using %s (tx) and %s (rx) for DMA transfers\n",
 560                         dma_chan_name(as->dma.chan_tx),
 561                         dma_chan_name(as->dma.chan_rx));
 562         return 0;
 563 error:
 564         if (as->dma.chan_rx)
 565                 dma_release_channel(as->dma.chan_rx);
 566         if (!IS_ERR(as->dma.chan_tx))
 567                 dma_release_channel(as->dma.chan_tx);
 568         return err;
 569 }
 570
 571 static void atmel_spi_stop_dma(struct atmel_spi *as)
 572 {
 573         if (as->dma.chan_rx)
 574                 dmaengine_terminate_all(as->dma.chan_rx);
 575         if (as->dma.chan_tx)
 576                 dmaengine_terminate_all(as->dma.chan_tx);
 577 }
 578
 579 static void atmel_spi_release_dma(struct atmel_spi *as)
 580 {
 581         if (as->dma.chan_rx)
 582                 dma_release_channel(as->dma.chan_rx);
 583         if (as->dma.chan_tx)
 584                 dma_release_channel(as->dma.chan_tx);
 585 }
 586
 587 /* This function is called by the DMA driver from tasklet context */
 588 static void dma_callback(void *data)
 589 {
 590         struct spi_master       *master = data;
 591         struct atmel_spi        *as = spi_master_get_devdata(master);
 592
 593         complete(&as->xfer_completion);
 594 }
 595
 596 /*
 597  * Next transfer using PIO without FIFO.
 598  */
 599 static void atmel_spi_next_xfer_single(struct spi_master *master,
 600                                        struct spi_transfer *xfer)
 601 {
 602         struct atmel_spi        *as = spi_master_get_devdata(master);
 603         unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
 604
 605         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
 606
 607         /* Make sure data is not remaining in RDR */
 608         spi_readl(as, RDR);
 609         while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
 610                 spi_readl(as, RDR);
 611                 cpu_relax();
 612         }
 613
 614         if (xfer->tx_buf) {
 615                 if (xfer->bits_per_word > 8)
 616                         spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
 617                 else
 618                         spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
 619         } else {
 620                 spi_writel(as, TDR, 0);
 621         }
 622
 623         dev_dbg(master->dev.parent,
 624                 "  start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
 625                 xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
 626                 xfer->bits_per_word);
 627
 628         /* Enable relevant interrupts */
 629         spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES));
 630 }
 631
 632 /*
 633  * Next transfer using PIO with FIFO.
 634  */
 635 static void atmel_spi_next_xfer_fifo(struct spi_master *master,
 636                                      struct spi_transfer *xfer)
 637 {
 638         struct atmel_spi *as = spi_master_get_devdata(master);
 639         u32 current_remaining_data, num_data;
 640         u32 offset = xfer->len - as->current_remaining_bytes;
 641         const u16 *words = (const u16 *)((u8 *)xfer->tx_buf + offset);
 642         const u8  *bytes = (const u8  *)((u8 *)xfer->tx_buf + offset);
 643         u16 td0, td1;
 644         u32 fifomr;
 645
 646         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_fifo\n");
 647
 648         /* Compute the number of data to transfer in the current iteration */
 649         current_remaining_data = ((xfer->bits_per_word > 8) ?
 650                                   ((u32)as->current_remaining_bytes >> 1) :
 651                                   (u32)as->current_remaining_bytes);
 652         num_data = min(current_remaining_data, as->fifo_size);
 653
 654         /* Flush RX and TX FIFOs */
 655         spi_writel(as, CR, SPI_BIT(RXFCLR) | SPI_BIT(TXFCLR));
 656         while (spi_readl(as, FLR))
 657                 cpu_relax();
 658
 659         /* Set RX FIFO Threshold to the number of data to transfer */
 660         fifomr = spi_readl(as, FMR);
 661         spi_writel(as, FMR, SPI_BFINS(RXFTHRES, num_data, fifomr));
 662
 663         /* Clear FIFO flags in the Status Register, especially RXFTHF */
 664         (void)spi_readl(as, SR);
 665
 666         /* Fill TX FIFO */
 667         while (num_data >= 2) {
 668                 if (xfer->tx_buf) {
 669                         if (xfer->bits_per_word > 8) {
 670                                 td0 = *words++;
 671                                 td1 = *words++;
 672                         } else {
 673                                 td0 = *bytes++;
 674                                 td1 = *bytes++;
 675                         }
 676                 } else {
 677                         td0 = 0;
 678                         td1 = 0;
 679                 }
 680
 681                 spi_writel(as, TDR, (td1 << 16) | td0);
 682                 num_data -= 2;
 683         }
 684
 685         if (num_data) {
 686                 if (xfer->tx_buf) {
 687                         if (xfer->bits_per_word > 8)
 688                                 td0 = *words++;
 689                         else
 690                                 td0 = *bytes++;
 691                 } else {
 692                         td0 = 0;
 693                 }
 694
 695                 spi_writew(as, TDR, td0);
 696                 num_data--;
 697         }
 698
 699         dev_dbg(master->dev.parent,
 700                 "  start fifo xfer %p: len %u tx %p rx %p bitpw %d\n",
 701                 xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
 702                 xfer->bits_per_word);
 703
 704         /*
 705          * Enable RX FIFO Threshold Flag interrupt to be notified about
 706          * transfer completion.
 707          */
 708         spi_writel(as, IER, SPI_BIT(RXFTHF) | SPI_BIT(OVRES));
 709 }
 710
 711 /*
 712  * Next transfer using PIO.
 713  */
 714 static void atmel_spi_next_xfer_pio(struct spi_master *master,
 715                                     struct spi_transfer *xfer)
 716 {
 717         struct atmel_spi *as = spi_master_get_devdata(master);
 718
 719         if (as->fifo_size)
 720                 atmel_spi_next_xfer_fifo(master, xfer);
 721         else
 722                 atmel_spi_next_xfer_single(master, xfer);
 723 }
 724
 725 /*
 726  * Submit next transfer for DMA.
 727  */
 728 static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
 729                                 struct spi_transfer *xfer,
 730                                 u32 *plen)
 731 {
 732         struct atmel_spi        *as = spi_master_get_devdata(master);
 733         struct dma_chan         *rxchan = as->dma.chan_rx;
 734         struct dma_chan         *txchan = as->dma.chan_tx;
 735         struct dma_async_tx_descriptor *rxdesc;
 736         struct dma_async_tx_descriptor *txdesc;
 737         struct dma_slave_config slave_config;
 738         dma_cookie_t            cookie;
 739         u32     len = *plen;
 740
 741         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
 742
 743         /* Check that the channels are available */
 744         if (!rxchan || !txchan)
 745                 return -ENODEV;
 746
 747         /* release lock for DMA operations */
 748         atmel_spi_unlock(as);
 749
 750         /* prepare the RX dma transfer */
 751         sg_init_table(&as->dma.sgrx, 1);
 752         if (xfer->rx_buf) {
 753                 as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen;
 754         } else {
 755                 as->dma.sgrx.dma_address = as->buffer_dma;
 756                 if (len > BUFFER_SIZE)
 757                         len = BUFFER_SIZE;
 758         }
 759
 760         /* prepare the TX dma transfer */
 761         sg_init_table(&as->dma.sgtx, 1);
 762         if (xfer->tx_buf) {
 763                 as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen;
 764         } else {
 765                 as->dma.sgtx.dma_address = as->buffer_dma;
 766                 if (len > BUFFER_SIZE)
 767                         len = BUFFER_SIZE;
 768                 memset(as->buffer, 0, len);
 769         }
 770
 771         sg_dma_len(&as->dma.sgtx) = len;
 772         sg_dma_len(&as->dma.sgrx) = len;
 773
 774         *plen = len;
 775
 776         if (atmel_spi_dma_slave_config(as, &slave_config,
 777                                        xfer->bits_per_word))
 778                 goto err_exit;
 779
 780         /* Send both scatterlists */
 781         rxdesc = dmaengine_prep_slave_sg(rxchan, &as->dma.sgrx, 1,
 782                                          DMA_FROM_DEVICE,
 783                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 784         if (!rxdesc)
 785                 goto err_dma;
 786
 787         txdesc = dmaengine_prep_slave_sg(txchan, &as->dma.sgtx, 1,
 788                                          DMA_TO_DEVICE,
 789                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 790         if (!txdesc)
 791                 goto err_dma;
 792
 793         dev_dbg(master->dev.parent,
 794                 "  start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 795                 xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
 796                 xfer->rx_buf, (unsigned long long)xfer->rx_dma);
 797
 798         /* Enable relevant interrupts */
 799         spi_writel(as, IER, SPI_BIT(OVRES));
 800
 801         /* Put the callback on the RX transfer only, that should finish last */
 802         rxdesc->callback = dma_callback;
 803         rxdesc->callback_param = master;
 804
 805         /* Submit and fire RX and TX with TX last so we're ready to read! */
 806         cookie = rxdesc->tx_submit(rxdesc);
 807         if (dma_submit_error(cookie))
 808                 goto err_dma;
 809         cookie = txdesc->tx_submit(txdesc);
 810         if (dma_submit_error(cookie))
 811                 goto err_dma;
 812         rxchan->device->device_issue_pending(rxchan);
 813         txchan->device->device_issue_pending(txchan);
 814
 815         /* take back lock */
 816         atmel_spi_lock(as);
 817         return 0;
 818
 819 err_dma:
 820         spi_writel(as, IDR, SPI_BIT(OVRES));
 821         atmel_spi_stop_dma(as);
 822 err_exit:
 823         atmel_spi_lock(as);
 824         return -ENOMEM;
 825 }
 826
 827 static void atmel_spi_next_xfer_data(struct spi_master *master,
 828                                 struct spi_transfer *xfer,
 829                                 dma_addr_t *tx_dma,
 830                                 dma_addr_t *rx_dma,
 831                                 u32 *plen)
 832 {
 833         struct atmel_spi        *as = spi_master_get_devdata(master);
 834         u32                     len = *plen;
 835
 836         /* use scratch buffer only when rx or tx data is unspecified */
 837         if (xfer->rx_buf)
 838                 *rx_dma = xfer->rx_dma + xfer->len - *plen;
 839         else {
 840                 *rx_dma = as->buffer_dma;
 841                 if (len > BUFFER_SIZE)
 842                         len = BUFFER_SIZE;
 843         }
 844
 845         if (xfer->tx_buf)
 846                 *tx_dma = xfer->tx_dma + xfer->len - *plen;
 847         else {
 848                 *tx_dma = as->buffer_dma;
 849                 if (len > BUFFER_SIZE)
 850                         len = BUFFER_SIZE;
 851                 memset(as->buffer, 0, len);
 852                 dma_sync_single_for_device(&as->pdev->dev,
 853                                 as->buffer_dma, len, DMA_TO_DEVICE);
 854         }
 855
 856         *plen = len;
 857 }
 858
 859 static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
 860                                     struct spi_device *spi,
 861                                     struct spi_transfer *xfer)
 862 {
 863         u32                     scbr, csr;
 864         unsigned long           bus_hz;
 865
 866         /* v1 chips start out at half the peripheral bus speed. */
 867         bus_hz = clk_get_rate(as->clk);
 868         if (!atmel_spi_is_v2(as))
 869                 bus_hz /= 2;
 870
 871         /*
 872          * Calculate the lowest divider that satisfies the
 873          * constraint, assuming div32/fdiv/mbz == 0.
 874          */
 875         scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
 876
 877         /*
 878          * If the resulting divider doesn't fit into the
 879          * register bitfield, we can't satisfy the constraint.
 880          */
 881         if (scbr >= (1 << SPI_SCBR_SIZE)) {
 882                 dev_err(&spi->dev,
 883                         "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
 884                         xfer->speed_hz, scbr, bus_hz/255);
 885                 return -EINVAL;
 886         }
 887         if (scbr == 0) {
 888                 dev_err(&spi->dev,
 889                         "setup: %d Hz too high, scbr %u; max %ld Hz\n",
 890                         xfer->speed_hz, scbr, bus_hz);
 891                 return -EINVAL;
 892         }
 893         csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
 894         csr = SPI_BFINS(SCBR, scbr, csr);
 895         spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 896
 897         return 0;
 898 }
 899
 900 /*
 901  * Submit next transfer for PDC.
 902  * lock is held, spi irq is blocked
 903  */
 904 static void atmel_spi_pdc_next_xfer(struct spi_master *master,
 905                                         struct spi_message *msg,
 906                                         struct spi_transfer *xfer)
 907 {
 908         struct atmel_spi        *as = spi_master_get_devdata(master);
 909         u32                     len;
 910         dma_addr_t              tx_dma, rx_dma;
 911
 912         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 913
 914         len = as->current_remaining_bytes;
 915         atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 916         as->current_remaining_bytes -= len;
 917
 918         spi_writel(as, RPR, rx_dma);
 919         spi_writel(as, TPR, tx_dma);
 920
 921         if (msg->spi->bits_per_word > 8)
 922                 len >>= 1;
 923         spi_writel(as, RCR, len);
 924         spi_writel(as, TCR, len);
 925
 926         dev_dbg(&msg->spi->dev,
 927                 "  start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 928                 xfer, xfer->len, xfer->tx_buf,
 929                 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
 930                 (unsigned long long)xfer->rx_dma);
 931
 932         if (as->current_remaining_bytes) {
 933                 len = as->current_remaining_bytes;
 934                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 935                 as->current_remaining_bytes -= len;
 936
 937                 spi_writel(as, RNPR, rx_dma);
 938                 spi_writel(as, TNPR, tx_dma);
 939
 940                 if (msg->spi->bits_per_word > 8)
 941                         len >>= 1;
 942                 spi_writel(as, RNCR, len);
 943                 spi_writel(as, TNCR, len);
 944
 945                 dev_dbg(&msg->spi->dev,
 946                         "  next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 947                         xfer, xfer->len, xfer->tx_buf,
 948                         (unsigned long long)xfer->tx_dma, xfer->rx_buf,
 949                         (unsigned long long)xfer->rx_dma);
 950         }
 951
 952         /* REVISIT: We're waiting for RXBUFF before we start the next
 953          * transfer because we need to handle some difficult timing
 954          * issues otherwise. If we wait for TXBUFE in one transfer and
 955          * then starts waiting for RXBUFF in the next, it's difficult
 956          * to tell the difference between the RXBUFF interrupt we're
 957          * actually waiting for and the RXBUFF interrupt of the
 958          * previous transfer.
 959          *
 960          * It should be doable, though. Just not now...
 961          */
 962         spi_writel(as, IER, SPI_BIT(RXBUFF) | SPI_BIT(OVRES));
 963         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 964 }
 965
 966 /*
 967  * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
 968  *  - The buffer is either valid for CPU access, else NULL
 969  *  - If the buffer is valid, so is its DMA address
 970  *
 971  * This driver manages the dma address unless message->is_dma_mapped.
 972  */
 973 static int
 974 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 975 {
 976         struct device   *dev = &as->pdev->dev;
 977
 978         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 979         if (xfer->tx_buf) {
 980                 /* tx_buf is a const void* where we need a void * for the dma
 981                  * mapping */
 982                 void *nonconst_tx = (void *)xfer->tx_buf;
 983
 984                 xfer->tx_dma = dma_map_single(dev,
 985                                 nonconst_tx, xfer->len,
 986                                 DMA_TO_DEVICE);
 987                 if (dma_mapping_error(dev, xfer->tx_dma))
 988                         return -ENOMEM;
 989         }
 990         if (xfer->rx_buf) {
 991                 xfer->rx_dma = dma_map_single(dev,
 992                                 xfer->rx_buf, xfer->len,
 993                                 DMA_FROM_DEVICE);
 994                 if (dma_mapping_error(dev, xfer->rx_dma)) {
 995                         if (xfer->tx_buf)
 996                                 dma_unmap_single(dev,
 997                                                 xfer->tx_dma, xfer->len,
 998                                                 DMA_TO_DEVICE);
 999                         return -ENOMEM;
1000                 }
1001         }
1002         return 0;
1003 }
1004
1005 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
1006                                      struct spi_transfer *xfer)
1007 {
1008         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
1009                 dma_unmap_single(master->dev.parent, xfer->tx_dma,
1010                                  xfer->len, DMA_TO_DEVICE);
1011         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
1012                 dma_unmap_single(master->dev.parent, xfer->rx_dma,
1013                                  xfer->len, DMA_FROM_DEVICE);
1014 }
1015
1016 static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
1017 {
1018         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1019 }
1020
1021 static void
1022 atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer)
1023 {
1024         u8              *rxp;
1025         u16             *rxp16;
1026         unsigned long   xfer_pos = xfer->len - as->current_remaining_bytes;
1027
1028         if (xfer->rx_buf) {
1029                 if (xfer->bits_per_word > 8) {
1030                         rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
1031                         *rxp16 = spi_readl(as, RDR);
1032                 } else {
1033                         rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
1034                         *rxp = spi_readl(as, RDR);
1035                 }
1036         } else {
1037                 spi_readl(as, RDR);
1038         }
1039         if (xfer->bits_per_word > 8) {
1040                 if (as->current_remaining_bytes > 2)
1041                         as->current_remaining_bytes -= 2;
1042                 else
1043                         as->current_remaining_bytes = 0;
1044         } else {
1045                 as->current_remaining_bytes--;
1046         }
1047 }
1048
1049 static void
1050 atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer)
1051 {
1052         u32 fifolr = spi_readl(as, FLR);
1053         u32 num_bytes, num_data = SPI_BFEXT(RXFL, fifolr);
1054         u32 offset = xfer->len - as->current_remaining_bytes;
1055         u16 *words = (u16 *)((u8 *)xfer->rx_buf + offset);
1056         u8  *bytes = (u8  *)((u8 *)xfer->rx_buf + offset);
1057         u16 rd; /* RD field is the lowest 16 bits of RDR */
1058
1059         /* Update the number of remaining bytes to transfer */
1060         num_bytes = ((xfer->bits_per_word > 8) ?
1061                      (num_data << 1) :
1062                      num_data);
1063
1064         if (as->current_remaining_bytes > num_bytes)
1065                 as->current_remaining_bytes -= num_bytes;
1066         else
1067                 as->current_remaining_bytes = 0;
1068
1069         /* Handle odd number of bytes when data are more than 8bit width */
1070         if (xfer->bits_per_word > 8)
1071                 as->current_remaining_bytes &= ~0x1;
1072
1073         /* Read data */
1074         while (num_data) {
1075                 rd = spi_readl(as, RDR);
1076                 if (xfer->rx_buf) {
1077                         if (xfer->bits_per_word > 8)
1078                                 *words++ = rd;
1079                         else
1080                                 *bytes++ = rd;
1081                 }
1082                 num_data--;
1083         }
1084 }
1085
1086 /* Called from IRQ
1087  *
1088  * Must update "current_remaining_bytes" to keep track of data
1089  * to transfer.
1090  */
1091 static void
1092 atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
1093 {
1094         if (as->fifo_size)
1095                 atmel_spi_pump_fifo_data(as, xfer);
1096         else
1097                 atmel_spi_pump_single_data(as, xfer);
1098 }
1099
1100 /* Interrupt
1101  *
1102  * No need for locking in this Interrupt handler: done_status is the
1103  * only information modified.
1104  */
1105 static irqreturn_t
1106 atmel_spi_pio_interrupt(int irq, void *dev_id)
1107 {
1108         struct spi_master       *master = dev_id;
1109         struct atmel_spi        *as = spi_master_get_devdata(master);
1110         u32                     status, pending, imr;
1111         struct spi_transfer     *xfer;
1112         int                     ret = IRQ_NONE;
1113
1114         imr = spi_readl(as, IMR);
1115         status = spi_readl(as, SR);
1116         pending = status & imr;
1117
1118         if (pending & SPI_BIT(OVRES)) {
1119                 ret = IRQ_HANDLED;
1120                 spi_writel(as, IDR, SPI_BIT(OVRES));
1121                 dev_warn(master->dev.parent, "overrun\n");
1122
1123                 /*
1124                  * When we get an overrun, we disregard the current
1125                  * transfer. Data will not be copied back from any
1126                  * bounce buffer and msg->actual_len will not be
1127                  * updated with the last xfer.
1128                  *
1129                  * We will also not process any remaning transfers in
1130                  * the message.
1131                  */
1132                 as->done_status = -EIO;
1133                 smp_wmb();
1134
1135                 /* Clear any overrun happening while cleaning up */
1136                 spi_readl(as, SR);
1137
1138                 complete(&as->xfer_completion);
1139
1140         } else if (pending & (SPI_BIT(RDRF) | SPI_BIT(RXFTHF))) {
1141                 atmel_spi_lock(as);
1142
1143                 if (as->current_remaining_bytes) {
1144                         ret = IRQ_HANDLED;
1145                         xfer = as->current_transfer;
1146                         atmel_spi_pump_pio_data(as, xfer);
1147                         if (!as->current_remaining_bytes)
1148                                 spi_writel(as, IDR, pending);
1149
1150                         complete(&as->xfer_completion);
1151                 }
1152
1153                 atmel_spi_unlock(as);
1154         } else {
1155                 WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
1156                 ret = IRQ_HANDLED;
1157                 spi_writel(as, IDR, pending);
1158         }
1159
1160         return ret;
1161 }
1162
1163 static irqreturn_t
1164 atmel_spi_pdc_interrupt(int irq, void *dev_id)
1165 {
1166         struct spi_master       *master = dev_id;
1167         struct atmel_spi        *as = spi_master_get_devdata(master);
1168         u32                     status, pending, imr;
1169         int                     ret = IRQ_NONE;
1170
1171         imr = spi_readl(as, IMR);
1172         status = spi_readl(as, SR);
1173         pending = status & imr;
1174
1175         if (pending & SPI_BIT(OVRES)) {
1176
1177                 ret = IRQ_HANDLED;
1178
1179                 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
1180                                      | SPI_BIT(OVRES)));
1181
1182                 /* Clear any overrun happening while cleaning up */
1183                 spi_readl(as, SR);
1184
1185                 as->done_status = -EIO;
1186
1187                 complete(&as->xfer_completion);
1188
1189         } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
1190                 ret = IRQ_HANDLED;
1191
1192                 spi_writel(as, IDR, pending);
1193
1194                 complete(&as->xfer_completion);
1195         }
1196
1197         return ret;
1198 }
1199
1200 static int atmel_spi_setup(struct spi_device *spi)
1201 {
1202         struct atmel_spi        *as;
1203         struct atmel_spi_device *asd;
1204         u32                     csr;
1205         unsigned int            bits = spi->bits_per_word;
1206         unsigned int            npcs_pin;
1207         int                     ret;
1208
1209         as = spi_master_get_devdata(spi->master);
1210
1211         /* see notes above re chipselect */
1212         if (!atmel_spi_is_v2(as)
1213                         && spi->chip_select == 0
1214                         && (spi->mode & SPI_CS_HIGH)) {
1215                 dev_dbg(&spi->dev, "setup: can't be active-high\n");
1216                 return -EINVAL;
1217         }
1218
1219         csr = SPI_BF(BITS, bits - 8);
1220         if (spi->mode & SPI_CPOL)
1221                 csr |= SPI_BIT(CPOL);
1222         if (!(spi->mode & SPI_CPHA))
1223                 csr |= SPI_BIT(NCPHA);
1224         if (!as->use_cs_gpios)
1225                 csr |= SPI_BIT(CSAAT);
1226
1227         /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
1228          *
1229          * DLYBCT would add delays between words, slowing down transfers.
1230          * It could potentially be useful to cope with DMA bottlenecks, but
1231          * in those cases it's probably best to just use a lower bitrate.
1232          */
1233         csr |= SPI_BF(DLYBS, 0);
1234         csr |= SPI_BF(DLYBCT, 0);
1235
1236         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
1237         npcs_pin = (unsigned long)spi->controller_data;
1238
1239         if (!as->use_cs_gpios)
1240                 npcs_pin = spi->chip_select;
1241         else if (gpio_is_valid(spi->cs_gpio))
1242                 npcs_pin = spi->cs_gpio;
1243
1244         asd = spi->controller_state;
1245         if (!asd) {
1246                 asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
1247                 if (!asd)
1248                         return -ENOMEM;
1249
1250                 if (as->use_cs_gpios) {
1251                         ret = gpio_request(npcs_pin, dev_name(&spi->dev));
1252                         if (ret) {
1253                                 kfree(asd);
1254                                 return ret;
1255                         }
1256
1257                         gpio_direction_output(npcs_pin,
1258                                               !(spi->mode & SPI_CS_HIGH));
1259                 }
1260
1261                 asd->npcs_pin = npcs_pin;
1262                 spi->controller_state = asd;
1263         }
1264
1265         asd->csr = csr;
1266
1267         dev_dbg(&spi->dev,
1268                 "setup: bpw %u mode 0x%x -> csr%d %08x\n",
1269                 bits, spi->mode, spi->chip_select, csr);
1270
1271         if (!atmel_spi_is_v2(as))
1272                 spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
1273
1274         return 0;
1275 }
1276
1277 static int atmel_spi_one_transfer(struct spi_master *master,
1278                                         struct spi_message *msg,
1279                                         struct spi_transfer *xfer)
1280 {
1281         struct atmel_spi        *as;
1282         struct spi_device       *spi = msg->spi;
1283         u8                      bits;
1284         u32                     len;
1285         struct atmel_spi_device *asd;
1286         int                     timeout;
1287         int                     ret;
1288         unsigned long           dma_timeout;
1289
1290         as = spi_master_get_devdata(master);
1291
1292         if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1293                 dev_dbg(&spi->dev, "missing rx or tx buf\n");
1294                 return -EINVAL;
1295         }
1296
1297         asd = spi->controller_state;
1298         bits = (asd->csr >> 4) & 0xf;
1299         if (bits != xfer->bits_per_word - 8) {
1300                 dev_dbg(&spi->dev,
1301                         "you can't yet change bits_per_word in transfers\n");
1302                 return -ENOPROTOOPT;
1303         }
1304
1305         /*
1306          * DMA map early, for performance (empties dcache ASAP) and
1307          * better fault reporting.
1308          */
1309         if ((!msg->is_dma_mapped)
1310                 && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) {
1311                 if (atmel_spi_dma_map_xfer(as, xfer) < 0)
1312                         return -ENOMEM;
1313         }
1314
1315         atmel_spi_set_xfer_speed(as, msg->spi, xfer);
1316
1317         as->done_status = 0;
1318         as->current_transfer = xfer;
1319         as->current_remaining_bytes = xfer->len;
1320         while (as->current_remaining_bytes) {
1321                 reinit_completion(&as->xfer_completion);
1322
1323                 if (as->use_pdc) {
1324                         atmel_spi_pdc_next_xfer(master, msg, xfer);
1325                 } else if (atmel_spi_use_dma(as, xfer)) {
1326                         len = as->current_remaining_bytes;
1327                         ret = atmel_spi_next_xfer_dma_submit(master,
1328                                                                 xfer, &len);
1329                         if (ret) {
1330                                 dev_err(&spi->dev,
1331                                         "unable to use DMA, fallback to PIO\n");
1332                                 atmel_spi_next_xfer_pio(master, xfer);
1333                         } else {
1334                                 as->current_remaining_bytes -= len;
1335                                 if (as->current_remaining_bytes < 0)
1336                                         as->current_remaining_bytes = 0;
1337                         }
1338                 } else {
1339                         atmel_spi_next_xfer_pio(master, xfer);
1340                 }
1341
1342                 /* interrupts are disabled, so free the lock for schedule */
1343                 atmel_spi_unlock(as);
1344                 dma_timeout = wait_for_completion_timeout(&as->xfer_completion,
1345                                                           SPI_DMA_TIMEOUT);
1346                 atmel_spi_lock(as);
1347                 if (WARN_ON(dma_timeout == 0)) {
1348                         dev_err(&spi->dev, "spi transfer timeout\n");
1349                         as->done_status = -EIO;
1350                 }
1351
1352                 if (as->done_status)
1353                         break;
1354         }
1355
1356         if (as->done_status) {
1357                 if (as->use_pdc) {
1358                         dev_warn(master->dev.parent,
1359                                 "overrun (%u/%u remaining)\n",
1360                                 spi_readl(as, TCR), spi_readl(as, RCR));
1361
1362                         /*
1363                          * Clean up DMA registers and make sure the data
1364                          * registers are empty.
1365                          */
1366                         spi_writel(as, RNCR, 0);
1367                         spi_writel(as, TNCR, 0);
1368                         spi_writel(as, RCR, 0);
1369                         spi_writel(as, TCR, 0);
1370                         for (timeout = 1000; timeout; timeout--)
1371                                 if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
1372                                         break;
1373                         if (!timeout)
1374                                 dev_warn(master->dev.parent,
1375                                          "timeout waiting for TXEMPTY");
1376                         while (spi_readl(as, SR) & SPI_BIT(RDRF))
1377                                 spi_readl(as, RDR);
1378
1379                         /* Clear any overrun happening while cleaning up */
1380                         spi_readl(as, SR);
1381
1382                 } else if (atmel_spi_use_dma(as, xfer)) {
1383                         atmel_spi_stop_dma(as);
1384                 }
1385
1386                 if (!msg->is_dma_mapped
1387                         && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1388                         atmel_spi_dma_unmap_xfer(master, xfer);
1389
1390                 return 0;
1391
1392         } else {
1393                 /* only update length if no error */
1394                 msg->actual_length += xfer->len;
1395         }
1396
1397         if (!msg->is_dma_mapped
1398                 && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1399                 atmel_spi_dma_unmap_xfer(master, xfer);
1400
1401         if (xfer->delay_usecs)
1402                 udelay(xfer->delay_usecs);
1403
1404         if (xfer->cs_change) {
1405                 if (list_is_last(&xfer->transfer_list,
1406                                  &msg->transfers)) {
1407                         as->keep_cs = true;
1408                 } else {
1409                         as->cs_active = !as->cs_active;
1410                         if (as->cs_active)
1411                                 cs_activate(as, msg->spi);
1412                         else
1413                                 cs_deactivate(as, msg->spi);
1414                 }
1415         }
1416
1417         return 0;
1418 }
1419
1420 static int atmel_spi_transfer_one_message(struct spi_master *master,
1421                                                 struct spi_message *msg)
1422 {
1423         struct atmel_spi *as;
1424         struct spi_transfer *xfer;
1425         struct spi_device *spi = msg->spi;
1426         int ret = 0;
1427
1428         as = spi_master_get_devdata(master);
1429
1430         dev_dbg(&spi->dev, "new message %p submitted for %s\n",
1431                                         msg, dev_name(&spi->dev));
1432
1433         atmel_spi_lock(as);
1434         cs_activate(as, spi);
1435
1436         as->cs_active = true;
1437         as->keep_cs = false;
1438
1439         msg->status = 0;
1440         msg->actual_length = 0;
1441
1442         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1443                 ret = atmel_spi_one_transfer(master, msg, xfer);
1444                 if (ret)
1445                         goto msg_done;
1446         }
1447
1448         if (as->use_pdc)
1449                 atmel_spi_disable_pdc_transfer(as);
1450
1451         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1452                 dev_dbg(&spi->dev,
1453                         "  xfer %p: len %u tx %p/%pad rx %p/%pad\n",
1454                         xfer, xfer->len,
1455                         xfer->tx_buf, &xfer->tx_dma,
1456                         xfer->rx_buf, &xfer->rx_dma);
1457         }
1458
1459 msg_done:
1460         if (!as->keep_cs)
1461                 cs_deactivate(as, msg->spi);
1462
1463         atmel_spi_unlock(as);
1464
1465         msg->status = as->done_status;
1466         spi_finalize_current_message(spi->master);
1467
1468         return ret;
1469 }
1470
1471 static void atmel_spi_cleanup(struct spi_device *spi)
1472 {
1473         struct atmel_spi_device *asd = spi->controller_state;
1474         unsigned                gpio = (unsigned long) spi->controller_data;
1475
1476         if (!asd)
1477                 return;
1478
1479         spi->controller_state = NULL;
1480         gpio_free(gpio);
1481         kfree(asd);
1482 }
1483
1484 static inline unsigned int atmel_get_version(struct atmel_spi *as)
1485 {
1486         return spi_readl(as, VERSION) & 0x00000fff;
1487 }
1488
1489 static void atmel_get_caps(struct atmel_spi *as)
1490 {
1491         unsigned int version;
1492
1493         version = atmel_get_version(as);
1494         dev_info(&as->pdev->dev, "version: 0x%x\n", version);
1495
1496         as->caps.is_spi2 = version > 0x121;
1497         as->caps.has_wdrbt = version >= 0x210;
1498         as->caps.has_dma_support = version >= 0x212;
1499 }
1500
1501 /*-------------------------------------------------------------------------*/
1502
1503 static int atmel_spi_probe(struct platform_device *pdev)
1504 {
1505         struct resource         *regs;
1506         int                     irq;
1507         struct clk              *clk;
1508         int                     ret;
1509         struct spi_master       *master;
1510         struct atmel_spi        *as;
1511
1512         /* Select default pin state */
1513         pinctrl_pm_select_default_state(&pdev->dev);
1514
1515         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1516         if (!regs)
1517                 return -ENXIO;
1518
1519         irq = platform_get_irq(pdev, 0);
1520         if (irq < 0)
1521                 return irq;
1522
1523         clk = devm_clk_get(&pdev->dev, "spi_clk");
1524         if (IS_ERR(clk))
1525                 return PTR_ERR(clk);
1526
1527         /* setup spi core then atmel-specific driver state */
1528         ret = -ENOMEM;
1529         master = spi_alloc_master(&pdev->dev, sizeof(*as));
1530         if (!master)
1531                 goto out_free;
1532
1533         /* the spi->mode bits understood by this driver: */
1534         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1535         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
1536         master->dev.of_node = pdev->dev.of_node;
1537         master->bus_num = pdev->id;
1538         master->num_chipselect = master->dev.of_node ? 0 : 4;
1539         master->setup = atmel_spi_setup;
1540         master->transfer_one_message = atmel_spi_transfer_one_message;
1541         master->cleanup = atmel_spi_cleanup;
1542         master->auto_runtime_pm = true;
1543         platform_set_drvdata(pdev, master);
1544
1545         as = spi_master_get_devdata(master);
1546
1547         /*
1548          * Scratch buffer is used for throwaway rx and tx data.
1549          * It's coherent to minimize dcache pollution.
1550          */
1551         as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
1552                                         &as->buffer_dma, GFP_KERNEL);
1553         if (!as->buffer)
1554                 goto out_free;
1555
1556         spin_lock_init(&as->lock);
1557
1558         as->pdev = pdev;
1559         as->regs = devm_ioremap_resource(&pdev->dev, regs);
1560         if (IS_ERR(as->regs)) {
1561                 ret = PTR_ERR(as->regs);
1562                 goto out_free_buffer;
1563         }
1564         as->phybase = regs->start;
1565         as->irq = irq;
1566         as->clk = clk;
1567
1568         init_completion(&as->xfer_completion);
1569
1570         atmel_get_caps(as);
1571
1572         as->use_cs_gpios = true;
1573         if (atmel_spi_is_v2(as) &&
1574             pdev->dev.of_node &&
1575             !of_get_property(pdev->dev.of_node, "cs-gpios", NULL)) {
1576                 as->use_cs_gpios = false;
1577                 master->num_chipselect = 4;
1578         }
1579
1580         as->use_dma = false;
1581         as->use_pdc = false;
1582         if (as->caps.has_dma_support) {
1583                 ret = atmel_spi_configure_dma(as);
1584                 if (ret == 0)
1585                         as->use_dma = true;
1586                 else if (ret == -EPROBE_DEFER)
1587                         return ret;
1588         } else {
1589                 as->use_pdc = true;
1590         }
1591
1592         if (as->caps.has_dma_support && !as->use_dma)
1593                 dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
1594
1595         if (as->use_pdc) {
1596                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
1597                                         0, dev_name(&pdev->dev), master);
1598         } else {
1599                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
1600                                         0, dev_name(&pdev->dev), master);
1601         }
1602         if (ret)
1603                 goto out_unmap_regs;
1604
1605         /* Initialize the hardware */
1606         ret = clk_prepare_enable(clk);
1607         if (ret)
1608                 goto out_free_irq;
1609         spi_writel(as, CR, SPI_BIT(SWRST));
1610         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1611         if (as->caps.has_wdrbt) {
1612                 spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
1613                                 | SPI_BIT(MSTR));
1614         } else {
1615                 spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
1616         }
1617
1618         if (as->use_pdc)
1619                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1620         spi_writel(as, CR, SPI_BIT(SPIEN));
1621
1622         as->fifo_size = 0;
1623         if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
1624                                   &as->fifo_size)) {
1625                 dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size);
1626                 spi_writel(as, CR, SPI_BIT(FIFOEN));
1627         }
1628
1629         /* go! */
1630         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
1631                         (unsigned long)regs->start, irq);
1632
1633         pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
1634         pm_runtime_use_autosuspend(&pdev->dev);
1635         pm_runtime_set_active(&pdev->dev);
1636         pm_runtime_enable(&pdev->dev);
1637
1638         ret = devm_spi_register_master(&pdev->dev, master);
1639         if (ret)
1640                 goto out_free_dma;
1641
1642         return 0;
1643
1644 out_free_dma:
1645         pm_runtime_disable(&pdev->dev);
1646         pm_runtime_set_suspended(&pdev->dev);
1647
1648         if (as->use_dma)
1649                 atmel_spi_release_dma(as);
1650
1651         spi_writel(as, CR, SPI_BIT(SWRST));
1652         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1653         clk_disable_unprepare(clk);
1654 out_free_irq:
1655 out_unmap_regs:
1656 out_free_buffer:
1657         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1658                         as->buffer_dma);
1659 out_free:
1660         spi_master_put(master);
1661         return ret;
1662 }
1663
1664 static int atmel_spi_remove(struct platform_device *pdev)
1665 {
1666         struct spi_master       *master = platform_get_drvdata(pdev);
1667         struct atmel_spi        *as = spi_master_get_devdata(master);
1668
1669         pm_runtime_get_sync(&pdev->dev);
1670
1671         /* reset the hardware and block queue progress */
1672         spin_lock_irq(&as->lock);
1673         if (as->use_dma) {
1674                 atmel_spi_stop_dma(as);
1675                 atmel_spi_release_dma(as);
1676         }
1677
1678         spi_writel(as, CR, SPI_BIT(SWRST));
1679         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1680         spi_readl(as, SR);
1681         spin_unlock_irq(&as->lock);
1682
1683         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1684                         as->buffer_dma);
1685
1686         clk_disable_unprepare(as->clk);
1687
1688         pm_runtime_put_noidle(&pdev->dev);
1689         pm_runtime_disable(&pdev->dev);
1690
1691         return 0;
1692 }
1693
1694 #ifdef CONFIG_PM
1695 static int atmel_spi_runtime_suspend(struct device *dev)
1696 {
1697         struct spi_master *master = dev_get_drvdata(dev);
1698         struct atmel_spi *as = spi_master_get_devdata(master);
1699
1700         clk_disable_unprepare(as->clk);
1701         pinctrl_pm_select_sleep_state(dev);
1702
1703         return 0;
1704 }
1705
1706 static int atmel_spi_runtime_resume(struct device *dev)
1707 {
1708         struct spi_master *master = dev_get_drvdata(dev);
1709         struct atmel_spi *as = spi_master_get_devdata(master);
1710
1711         pinctrl_pm_select_default_state(dev);
1712
1713         return clk_prepare_enable(as->clk);
1714 }
1715
1716 #ifdef CONFIG_PM_SLEEP
1717 static int atmel_spi_suspend(struct device *dev)
1718 {
1719         struct spi_master *master = dev_get_drvdata(dev);
1720         int ret;
1721
1722         /* Stop the queue running */
1723         ret = spi_master_suspend(master);
1724         if (ret) {
1725                 dev_warn(dev, "cannot suspend master\n");
1726                 return ret;
1727         }
1728
1729         if (!pm_runtime_suspended(dev))
1730                 atmel_spi_runtime_suspend(dev);
1731
1732         return 0;
1733 }
1734
1735 static int atmel_spi_resume(struct device *dev)
1736 {
1737         struct spi_master *master = dev_get_drvdata(dev);
1738         int ret;
1739
1740         if (!pm_runtime_suspended(dev)) {
1741                 ret = atmel_spi_runtime_resume(dev);
1742                 if (ret)
1743                         return ret;
1744         }
1745
1746         /* Start the queue running */
1747         ret = spi_master_resume(master);
1748         if (ret)
1749                 dev_err(dev, "problem starting queue (%d)\n", ret);
1750
1751         return ret;
1752 }
1753 #endif
1754
1755 static const struct dev_pm_ops atmel_spi_pm_ops = {
1756         SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
1757         SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
1758                            atmel_spi_runtime_resume, NULL)
1759 };
1760 #define ATMEL_SPI_PM_OPS        (&atmel_spi_pm_ops)
1761 #else
1762 #define ATMEL_SPI_PM_OPS        NULL
1763 #endif
1764
1765 #if defined(CONFIG_OF)
1766 static const struct of_device_id atmel_spi_dt_ids[] = {
1767         { .compatible = "atmel,at91rm9200-spi" },
1768         { /* sentinel */ }
1769 };
1770
1771 MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
1772 #endif
1773
1774 static struct platform_driver atmel_spi_driver = {
1775         .driver         = {
1776                 .name   = "atmel_spi",
1777                 .pm     = ATMEL_SPI_PM_OPS,
1778                 .of_match_table = of_match_ptr(atmel_spi_dt_ids),
1779         },
1780         .probe          = atmel_spi_probe,
1781         .remove         = atmel_spi_remove,
1782 };
1783 module_platform_driver(atmel_spi_driver);
1784
1785 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
1786 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1787 MODULE_LICENSE("GPL");
1788 MODULE_ALIAS("platform:atmel_spi");