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, 8))
 777                 goto err_exit;
 778
 779         /* Send both scatterlists */
 780         rxdesc = dmaengine_prep_slave_sg(rxchan, &as->dma.sgrx, 1,
 781                                          DMA_FROM_DEVICE,
 782                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 783         if (!rxdesc)
 784                 goto err_dma;
 785
 786         txdesc = dmaengine_prep_slave_sg(txchan, &as->dma.sgtx, 1,
 787                                          DMA_TO_DEVICE,
 788                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 789         if (!txdesc)
 790                 goto err_dma;
 791
 792         dev_dbg(master->dev.parent,
 793                 "  start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 794                 xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
 795                 xfer->rx_buf, (unsigned long long)xfer->rx_dma);
 796
 797         /* Enable relevant interrupts */
 798         spi_writel(as, IER, SPI_BIT(OVRES));
 799
 800         /* Put the callback on the RX transfer only, that should finish last */
 801         rxdesc->callback = dma_callback;
 802         rxdesc->callback_param = master;
 803
 804         /* Submit and fire RX and TX with TX last so we're ready to read! */
 805         cookie = rxdesc->tx_submit(rxdesc);
 806         if (dma_submit_error(cookie))
 807                 goto err_dma;
 808         cookie = txdesc->tx_submit(txdesc);
 809         if (dma_submit_error(cookie))
 810                 goto err_dma;
 811         rxchan->device->device_issue_pending(rxchan);
 812         txchan->device->device_issue_pending(txchan);
 813
 814         /* take back lock */
 815         atmel_spi_lock(as);
 816         return 0;
 817
 818 err_dma:
 819         spi_writel(as, IDR, SPI_BIT(OVRES));
 820         atmel_spi_stop_dma(as);
 821 err_exit:
 822         atmel_spi_lock(as);
 823         return -ENOMEM;
 824 }
 825
 826 static void atmel_spi_next_xfer_data(struct spi_master *master,
 827                                 struct spi_transfer *xfer,
 828                                 dma_addr_t *tx_dma,
 829                                 dma_addr_t *rx_dma,
 830                                 u32 *plen)
 831 {
 832         struct atmel_spi        *as = spi_master_get_devdata(master);
 833         u32                     len = *plen;
 834
 835         /* use scratch buffer only when rx or tx data is unspecified */
 836         if (xfer->rx_buf)
 837                 *rx_dma = xfer->rx_dma + xfer->len - *plen;
 838         else {
 839                 *rx_dma = as->buffer_dma;
 840                 if (len > BUFFER_SIZE)
 841                         len = BUFFER_SIZE;
 842         }
 843
 844         if (xfer->tx_buf)
 845                 *tx_dma = xfer->tx_dma + xfer->len - *plen;
 846         else {
 847                 *tx_dma = as->buffer_dma;
 848                 if (len > BUFFER_SIZE)
 849                         len = BUFFER_SIZE;
 850                 memset(as->buffer, 0, len);
 851                 dma_sync_single_for_device(&as->pdev->dev,
 852                                 as->buffer_dma, len, DMA_TO_DEVICE);
 853         }
 854
 855         *plen = len;
 856 }
 857
 858 static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
 859                                     struct spi_device *spi,
 860                                     struct spi_transfer *xfer)
 861 {
 862         u32                     scbr, csr;
 863         unsigned long           bus_hz;
 864
 865         /* v1 chips start out at half the peripheral bus speed. */
 866         bus_hz = clk_get_rate(as->clk);
 867         if (!atmel_spi_is_v2(as))
 868                 bus_hz /= 2;
 869
 870         /*
 871          * Calculate the lowest divider that satisfies the
 872          * constraint, assuming div32/fdiv/mbz == 0.
 873          */
 874         scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
 875
 876         /*
 877          * If the resulting divider doesn't fit into the
 878          * register bitfield, we can't satisfy the constraint.
 879          */
 880         if (scbr >= (1 << SPI_SCBR_SIZE)) {
 881                 dev_err(&spi->dev,
 882                         "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
 883                         xfer->speed_hz, scbr, bus_hz/255);
 884                 return -EINVAL;
 885         }
 886         if (scbr == 0) {
 887                 dev_err(&spi->dev,
 888                         "setup: %d Hz too high, scbr %u; max %ld Hz\n",
 889                         xfer->speed_hz, scbr, bus_hz);
 890                 return -EINVAL;
 891         }
 892         csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
 893         csr = SPI_BFINS(SCBR, scbr, csr);
 894         spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 895
 896         return 0;
 897 }
 898
 899 /*
 900  * Submit next transfer for PDC.
 901  * lock is held, spi irq is blocked
 902  */
 903 static void atmel_spi_pdc_next_xfer(struct spi_master *master,
 904                                         struct spi_message *msg,
 905                                         struct spi_transfer *xfer)
 906 {
 907         struct atmel_spi        *as = spi_master_get_devdata(master);
 908         u32                     len;
 909         dma_addr_t              tx_dma, rx_dma;
 910
 911         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 912
 913         len = as->current_remaining_bytes;
 914         atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 915         as->current_remaining_bytes -= len;
 916
 917         spi_writel(as, RPR, rx_dma);
 918         spi_writel(as, TPR, tx_dma);
 919
 920         if (msg->spi->bits_per_word > 8)
 921                 len >>= 1;
 922         spi_writel(as, RCR, len);
 923         spi_writel(as, TCR, len);
 924
 925         dev_dbg(&msg->spi->dev,
 926                 "  start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 927                 xfer, xfer->len, xfer->tx_buf,
 928                 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
 929                 (unsigned long long)xfer->rx_dma);
 930
 931         if (as->current_remaining_bytes) {
 932                 len = as->current_remaining_bytes;
 933                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 934                 as->current_remaining_bytes -= len;
 935
 936                 spi_writel(as, RNPR, rx_dma);
 937                 spi_writel(as, TNPR, tx_dma);
 938
 939                 if (msg->spi->bits_per_word > 8)
 940                         len >>= 1;
 941                 spi_writel(as, RNCR, len);
 942                 spi_writel(as, TNCR, len);
 943
 944                 dev_dbg(&msg->spi->dev,
 945                         "  next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 946                         xfer, xfer->len, xfer->tx_buf,
 947                         (unsigned long long)xfer->tx_dma, xfer->rx_buf,
 948                         (unsigned long long)xfer->rx_dma);
 949         }
 950
 951         /* REVISIT: We're waiting for RXBUFF before we start the next
 952          * transfer because we need to handle some difficult timing
 953          * issues otherwise. If we wait for TXBUFE in one transfer and
 954          * then starts waiting for RXBUFF in the next, it's difficult
 955          * to tell the difference between the RXBUFF interrupt we're
 956          * actually waiting for and the RXBUFF interrupt of the
 957          * previous transfer.
 958          *
 959          * It should be doable, though. Just not now...
 960          */
 961         spi_writel(as, IER, SPI_BIT(RXBUFF) | SPI_BIT(OVRES));
 962         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 963 }
 964
 965 /*
 966  * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
 967  *  - The buffer is either valid for CPU access, else NULL
 968  *  - If the buffer is valid, so is its DMA address
 969  *
 970  * This driver manages the dma address unless message->is_dma_mapped.
 971  */
 972 static int
 973 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 974 {
 975         struct device   *dev = &as->pdev->dev;
 976
 977         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 978         if (xfer->tx_buf) {
 979                 /* tx_buf is a const void* where we need a void * for the dma
 980                  * mapping */
 981                 void *nonconst_tx = (void *)xfer->tx_buf;
 982
 983                 xfer->tx_dma = dma_map_single(dev,
 984                                 nonconst_tx, xfer->len,
 985                                 DMA_TO_DEVICE);
 986                 if (dma_mapping_error(dev, xfer->tx_dma))
 987                         return -ENOMEM;
 988         }
 989         if (xfer->rx_buf) {
 990                 xfer->rx_dma = dma_map_single(dev,
 991                                 xfer->rx_buf, xfer->len,
 992                                 DMA_FROM_DEVICE);
 993                 if (dma_mapping_error(dev, xfer->rx_dma)) {
 994                         if (xfer->tx_buf)
 995                                 dma_unmap_single(dev,
 996                                                 xfer->tx_dma, xfer->len,
 997                                                 DMA_TO_DEVICE);
 998                         return -ENOMEM;
 999                 }
1000         }
1001         return 0;
1002 }
1003
1004 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
1005                                      struct spi_transfer *xfer)
1006 {
1007         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
1008                 dma_unmap_single(master->dev.parent, xfer->tx_dma,
1009                                  xfer->len, DMA_TO_DEVICE);
1010         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
1011                 dma_unmap_single(master->dev.parent, xfer->rx_dma,
1012                                  xfer->len, DMA_FROM_DEVICE);
1013 }
1014
1015 static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
1016 {
1017         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1018 }
1019
1020 static void
1021 atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer)
1022 {
1023         u8              *rxp;
1024         u16             *rxp16;
1025         unsigned long   xfer_pos = xfer->len - as->current_remaining_bytes;
1026
1027         if (xfer->rx_buf) {
1028                 if (xfer->bits_per_word > 8) {
1029                         rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
1030                         *rxp16 = spi_readl(as, RDR);
1031                 } else {
1032                         rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
1033                         *rxp = spi_readl(as, RDR);
1034                 }
1035         } else {
1036                 spi_readl(as, RDR);
1037         }
1038         if (xfer->bits_per_word > 8) {
1039                 if (as->current_remaining_bytes > 2)
1040                         as->current_remaining_bytes -= 2;
1041                 else
1042                         as->current_remaining_bytes = 0;
1043         } else {
1044                 as->current_remaining_bytes--;
1045         }
1046 }
1047
1048 static void
1049 atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer)
1050 {
1051         u32 fifolr = spi_readl(as, FLR);
1052         u32 num_bytes, num_data = SPI_BFEXT(RXFL, fifolr);
1053         u32 offset = xfer->len - as->current_remaining_bytes;
1054         u16 *words = (u16 *)((u8 *)xfer->rx_buf + offset);
1055         u8  *bytes = (u8  *)((u8 *)xfer->rx_buf + offset);
1056         u16 rd; /* RD field is the lowest 16 bits of RDR */
1057
1058         /* Update the number of remaining bytes to transfer */
1059         num_bytes = ((xfer->bits_per_word > 8) ?
1060                      (num_data << 1) :
1061                      num_data);
1062
1063         if (as->current_remaining_bytes > num_bytes)
1064                 as->current_remaining_bytes -= num_bytes;
1065         else
1066                 as->current_remaining_bytes = 0;
1067
1068         /* Handle odd number of bytes when data are more than 8bit width */
1069         if (xfer->bits_per_word > 8)
1070                 as->current_remaining_bytes &= ~0x1;
1071
1072         /* Read data */
1073         while (num_data) {
1074                 rd = spi_readl(as, RDR);
1075                 if (xfer->rx_buf) {
1076                         if (xfer->bits_per_word > 8)
1077                                 *words++ = rd;
1078                         else
1079                                 *bytes++ = rd;
1080                 }
1081                 num_data--;
1082         }
1083 }
1084
1085 /* Called from IRQ
1086  *
1087  * Must update "current_remaining_bytes" to keep track of data
1088  * to transfer.
1089  */
1090 static void
1091 atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
1092 {
1093         if (as->fifo_size)
1094                 atmel_spi_pump_fifo_data(as, xfer);
1095         else
1096                 atmel_spi_pump_single_data(as, xfer);
1097 }
1098
1099 /* Interrupt
1100  *
1101  * No need for locking in this Interrupt handler: done_status is the
1102  * only information modified.
1103  */
1104 static irqreturn_t
1105 atmel_spi_pio_interrupt(int irq, void *dev_id)
1106 {
1107         struct spi_master       *master = dev_id;
1108         struct atmel_spi        *as = spi_master_get_devdata(master);
1109         u32                     status, pending, imr;
1110         struct spi_transfer     *xfer;
1111         int                     ret = IRQ_NONE;
1112
1113         imr = spi_readl(as, IMR);
1114         status = spi_readl(as, SR);
1115         pending = status & imr;
1116
1117         if (pending & SPI_BIT(OVRES)) {
1118                 ret = IRQ_HANDLED;
1119                 spi_writel(as, IDR, SPI_BIT(OVRES));
1120                 dev_warn(master->dev.parent, "overrun\n");
1121
1122                 /*
1123                  * When we get an overrun, we disregard the current
1124                  * transfer. Data will not be copied back from any
1125                  * bounce buffer and msg->actual_len will not be
1126                  * updated with the last xfer.
1127                  *
1128                  * We will also not process any remaning transfers in
1129                  * the message.
1130                  */
1131                 as->done_status = -EIO;
1132                 smp_wmb();
1133
1134                 /* Clear any overrun happening while cleaning up */
1135                 spi_readl(as, SR);
1136
1137                 complete(&as->xfer_completion);
1138
1139         } else if (pending & (SPI_BIT(RDRF) | SPI_BIT(RXFTHF))) {
1140                 atmel_spi_lock(as);
1141
1142                 if (as->current_remaining_bytes) {
1143                         ret = IRQ_HANDLED;
1144                         xfer = as->current_transfer;
1145                         atmel_spi_pump_pio_data(as, xfer);
1146                         if (!as->current_remaining_bytes)
1147                                 spi_writel(as, IDR, pending);
1148
1149                         complete(&as->xfer_completion);
1150                 }
1151
1152                 atmel_spi_unlock(as);
1153         } else {
1154                 WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
1155                 ret = IRQ_HANDLED;
1156                 spi_writel(as, IDR, pending);
1157         }
1158
1159         return ret;
1160 }
1161
1162 static irqreturn_t
1163 atmel_spi_pdc_interrupt(int irq, void *dev_id)
1164 {
1165         struct spi_master       *master = dev_id;
1166         struct atmel_spi        *as = spi_master_get_devdata(master);
1167         u32                     status, pending, imr;
1168         int                     ret = IRQ_NONE;
1169
1170         imr = spi_readl(as, IMR);
1171         status = spi_readl(as, SR);
1172         pending = status & imr;
1173
1174         if (pending & SPI_BIT(OVRES)) {
1175
1176                 ret = IRQ_HANDLED;
1177
1178                 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
1179                                      | SPI_BIT(OVRES)));
1180
1181                 /* Clear any overrun happening while cleaning up */
1182                 spi_readl(as, SR);
1183
1184                 as->done_status = -EIO;
1185
1186                 complete(&as->xfer_completion);
1187
1188         } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
1189                 ret = IRQ_HANDLED;
1190
1191                 spi_writel(as, IDR, pending);
1192
1193                 complete(&as->xfer_completion);
1194         }
1195
1196         return ret;
1197 }
1198
1199 static int atmel_spi_setup(struct spi_device *spi)
1200 {
1201         struct atmel_spi        *as;
1202         struct atmel_spi_device *asd;
1203         u32                     csr;
1204         unsigned int            bits = spi->bits_per_word;
1205         unsigned int            npcs_pin;
1206         int                     ret;
1207
1208         as = spi_master_get_devdata(spi->master);
1209
1210         /* see notes above re chipselect */
1211         if (!atmel_spi_is_v2(as)
1212                         && spi->chip_select == 0
1213                         && (spi->mode & SPI_CS_HIGH)) {
1214                 dev_dbg(&spi->dev, "setup: can't be active-high\n");
1215                 return -EINVAL;
1216         }
1217
1218         csr = SPI_BF(BITS, bits - 8);
1219         if (spi->mode & SPI_CPOL)
1220                 csr |= SPI_BIT(CPOL);
1221         if (!(spi->mode & SPI_CPHA))
1222                 csr |= SPI_BIT(NCPHA);
1223         if (!as->use_cs_gpios)
1224                 csr |= SPI_BIT(CSAAT);
1225
1226         /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
1227          *
1228          * DLYBCT would add delays between words, slowing down transfers.
1229          * It could potentially be useful to cope with DMA bottlenecks, but
1230          * in those cases it's probably best to just use a lower bitrate.
1231          */
1232         csr |= SPI_BF(DLYBS, 0);
1233         csr |= SPI_BF(DLYBCT, 0);
1234
1235         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
1236         npcs_pin = (unsigned long)spi->controller_data;
1237
1238         if (!as->use_cs_gpios)
1239                 npcs_pin = spi->chip_select;
1240         else if (gpio_is_valid(spi->cs_gpio))
1241                 npcs_pin = spi->cs_gpio;
1242
1243         asd = spi->controller_state;
1244         if (!asd) {
1245                 asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
1246                 if (!asd)
1247                         return -ENOMEM;
1248
1249                 if (as->use_cs_gpios) {
1250                         ret = gpio_request(npcs_pin, dev_name(&spi->dev));
1251                         if (ret) {
1252                                 kfree(asd);
1253                                 return ret;
1254                         }
1255
1256                         gpio_direction_output(npcs_pin,
1257                                               !(spi->mode & SPI_CS_HIGH));
1258                 }
1259
1260                 asd->npcs_pin = npcs_pin;
1261                 spi->controller_state = asd;
1262         }
1263
1264         asd->csr = csr;
1265
1266         dev_dbg(&spi->dev,
1267                 "setup: bpw %u mode 0x%x -> csr%d %08x\n",
1268                 bits, spi->mode, spi->chip_select, csr);
1269
1270         if (!atmel_spi_is_v2(as))
1271                 spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
1272
1273         return 0;
1274 }
1275
1276 static int atmel_spi_one_transfer(struct spi_master *master,
1277                                         struct spi_message *msg,
1278                                         struct spi_transfer *xfer)
1279 {
1280         struct atmel_spi        *as;
1281         struct spi_device       *spi = msg->spi;
1282         u8                      bits;
1283         u32                     len;
1284         struct atmel_spi_device *asd;
1285         int                     timeout;
1286         int                     ret;
1287         unsigned long           dma_timeout;
1288
1289         as = spi_master_get_devdata(master);
1290
1291         if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1292                 dev_dbg(&spi->dev, "missing rx or tx buf\n");
1293                 return -EINVAL;
1294         }
1295
1296         asd = spi->controller_state;
1297         bits = (asd->csr >> 4) & 0xf;
1298         if (bits != xfer->bits_per_word - 8) {
1299                 dev_dbg(&spi->dev,
1300                         "you can't yet change bits_per_word in transfers\n");
1301                 return -ENOPROTOOPT;
1302         }
1303
1304         /*
1305          * DMA map early, for performance (empties dcache ASAP) and
1306          * better fault reporting.
1307          */
1308         if ((!msg->is_dma_mapped)
1309                 && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) {
1310                 if (atmel_spi_dma_map_xfer(as, xfer) < 0)
1311                         return -ENOMEM;
1312         }
1313
1314         atmel_spi_set_xfer_speed(as, msg->spi, xfer);
1315
1316         as->done_status = 0;
1317         as->current_transfer = xfer;
1318         as->current_remaining_bytes = xfer->len;
1319         while (as->current_remaining_bytes) {
1320                 reinit_completion(&as->xfer_completion);
1321
1322                 if (as->use_pdc) {
1323                         atmel_spi_pdc_next_xfer(master, msg, xfer);
1324                 } else if (atmel_spi_use_dma(as, xfer)) {
1325                         len = as->current_remaining_bytes;
1326                         ret = atmel_spi_next_xfer_dma_submit(master,
1327                                                                 xfer, &len);
1328                         if (ret) {
1329                                 dev_err(&spi->dev,
1330                                         "unable to use DMA, fallback to PIO\n");
1331                                 atmel_spi_next_xfer_pio(master, xfer);
1332                         } else {
1333                                 as->current_remaining_bytes -= len;
1334                                 if (as->current_remaining_bytes < 0)
1335                                         as->current_remaining_bytes = 0;
1336                         }
1337                 } else {
1338                         atmel_spi_next_xfer_pio(master, xfer);
1339                 }
1340
1341                 /* interrupts are disabled, so free the lock for schedule */
1342                 atmel_spi_unlock(as);
1343                 dma_timeout = wait_for_completion_timeout(&as->xfer_completion,
1344                                                           SPI_DMA_TIMEOUT);
1345                 atmel_spi_lock(as);
1346                 if (WARN_ON(dma_timeout == 0)) {
1347                         dev_err(&spi->dev, "spi transfer timeout\n");
1348                         as->done_status = -EIO;
1349                 }
1350
1351                 if (as->done_status)
1352                         break;
1353         }
1354
1355         if (as->done_status) {
1356                 if (as->use_pdc) {
1357                         dev_warn(master->dev.parent,
1358                                 "overrun (%u/%u remaining)\n",
1359                                 spi_readl(as, TCR), spi_readl(as, RCR));
1360
1361                         /*
1362                          * Clean up DMA registers and make sure the data
1363                          * registers are empty.
1364                          */
1365                         spi_writel(as, RNCR, 0);
1366                         spi_writel(as, TNCR, 0);
1367                         spi_writel(as, RCR, 0);
1368                         spi_writel(as, TCR, 0);
1369                         for (timeout = 1000; timeout; timeout--)
1370                                 if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
1371                                         break;
1372                         if (!timeout)
1373                                 dev_warn(master->dev.parent,
1374                                          "timeout waiting for TXEMPTY");
1375                         while (spi_readl(as, SR) & SPI_BIT(RDRF))
1376                                 spi_readl(as, RDR);
1377
1378                         /* Clear any overrun happening while cleaning up */
1379                         spi_readl(as, SR);
1380
1381                 } else if (atmel_spi_use_dma(as, xfer)) {
1382                         atmel_spi_stop_dma(as);
1383                 }
1384
1385                 if (!msg->is_dma_mapped
1386                         && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1387                         atmel_spi_dma_unmap_xfer(master, xfer);
1388
1389                 return 0;
1390
1391         } else {
1392                 /* only update length if no error */
1393                 msg->actual_length += xfer->len;
1394         }
1395
1396         if (!msg->is_dma_mapped
1397                 && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1398                 atmel_spi_dma_unmap_xfer(master, xfer);
1399
1400         if (xfer->delay_usecs)
1401                 udelay(xfer->delay_usecs);
1402
1403         if (xfer->cs_change) {
1404                 if (list_is_last(&xfer->transfer_list,
1405                                  &msg->transfers)) {
1406                         as->keep_cs = true;
1407                 } else {
1408                         as->cs_active = !as->cs_active;
1409                         if (as->cs_active)
1410                                 cs_activate(as, msg->spi);
1411                         else
1412                                 cs_deactivate(as, msg->spi);
1413                 }
1414         }
1415
1416         return 0;
1417 }
1418
1419 static int atmel_spi_transfer_one_message(struct spi_master *master,
1420                                                 struct spi_message *msg)
1421 {
1422         struct atmel_spi *as;
1423         struct spi_transfer *xfer;
1424         struct spi_device *spi = msg->spi;
1425         int ret = 0;
1426
1427         as = spi_master_get_devdata(master);
1428
1429         dev_dbg(&spi->dev, "new message %p submitted for %s\n",
1430                                         msg, dev_name(&spi->dev));
1431
1432         atmel_spi_lock(as);
1433         cs_activate(as, spi);
1434
1435         as->cs_active = true;
1436         as->keep_cs = false;
1437
1438         msg->status = 0;
1439         msg->actual_length = 0;
1440
1441         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1442                 ret = atmel_spi_one_transfer(master, msg, xfer);
1443                 if (ret)
1444                         goto msg_done;
1445         }
1446
1447         if (as->use_pdc)
1448                 atmel_spi_disable_pdc_transfer(as);
1449
1450         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1451                 dev_dbg(&spi->dev,
1452                         "  xfer %p: len %u tx %p/%pad rx %p/%pad\n",
1453                         xfer, xfer->len,
1454                         xfer->tx_buf, &xfer->tx_dma,
1455                         xfer->rx_buf, &xfer->rx_dma);
1456         }
1457
1458 msg_done:
1459         if (!as->keep_cs)
1460                 cs_deactivate(as, msg->spi);
1461
1462         atmel_spi_unlock(as);
1463
1464         msg->status = as->done_status;
1465         spi_finalize_current_message(spi->master);
1466
1467         return ret;
1468 }
1469
1470 static void atmel_spi_cleanup(struct spi_device *spi)
1471 {
1472         struct atmel_spi_device *asd = spi->controller_state;
1473         unsigned                gpio = (unsigned long) spi->controller_data;
1474
1475         if (!asd)
1476                 return;
1477
1478         spi->controller_state = NULL;
1479         gpio_free(gpio);
1480         kfree(asd);
1481 }
1482
1483 static inline unsigned int atmel_get_version(struct atmel_spi *as)
1484 {
1485         return spi_readl(as, VERSION) & 0x00000fff;
1486 }
1487
1488 static void atmel_get_caps(struct atmel_spi *as)
1489 {
1490         unsigned int version;
1491
1492         version = atmel_get_version(as);
1493         dev_info(&as->pdev->dev, "version: 0x%x\n", version);
1494
1495         as->caps.is_spi2 = version > 0x121;
1496         as->caps.has_wdrbt = version >= 0x210;
1497         as->caps.has_dma_support = version >= 0x212;
1498 }
1499
1500 /*-------------------------------------------------------------------------*/
1501
1502 static int atmel_spi_probe(struct platform_device *pdev)
1503 {
1504         struct resource         *regs;
1505         int                     irq;
1506         struct clk              *clk;
1507         int                     ret;
1508         struct spi_master       *master;
1509         struct atmel_spi        *as;
1510
1511         /* Select default pin state */
1512         pinctrl_pm_select_default_state(&pdev->dev);
1513
1514         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1515         if (!regs)
1516                 return -ENXIO;
1517
1518         irq = platform_get_irq(pdev, 0);
1519         if (irq < 0)
1520                 return irq;
1521
1522         clk = devm_clk_get(&pdev->dev, "spi_clk");
1523         if (IS_ERR(clk))
1524                 return PTR_ERR(clk);
1525
1526         /* setup spi core then atmel-specific driver state */
1527         ret = -ENOMEM;
1528         master = spi_alloc_master(&pdev->dev, sizeof(*as));
1529         if (!master)
1530                 goto out_free;
1531
1532         /* the spi->mode bits understood by this driver: */
1533         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1534         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
1535         master->dev.of_node = pdev->dev.of_node;
1536         master->bus_num = pdev->id;
1537         master->num_chipselect = master->dev.of_node ? 0 : 4;
1538         master->setup = atmel_spi_setup;
1539         master->transfer_one_message = atmel_spi_transfer_one_message;
1540         master->cleanup = atmel_spi_cleanup;
1541         master->auto_runtime_pm = true;
1542         platform_set_drvdata(pdev, master);
1543
1544         as = spi_master_get_devdata(master);
1545
1546         /*
1547          * Scratch buffer is used for throwaway rx and tx data.
1548          * It's coherent to minimize dcache pollution.
1549          */
1550         as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
1551                                         &as->buffer_dma, GFP_KERNEL);
1552         if (!as->buffer)
1553                 goto out_free;
1554
1555         spin_lock_init(&as->lock);
1556
1557         as->pdev = pdev;
1558         as->regs = devm_ioremap_resource(&pdev->dev, regs);
1559         if (IS_ERR(as->regs)) {
1560                 ret = PTR_ERR(as->regs);
1561                 goto out_free_buffer;
1562         }
1563         as->phybase = regs->start;
1564         as->irq = irq;
1565         as->clk = clk;
1566
1567         init_completion(&as->xfer_completion);
1568
1569         atmel_get_caps(as);
1570
1571         as->use_cs_gpios = true;
1572         if (atmel_spi_is_v2(as) &&
1573             !of_get_property(pdev->dev.of_node, "cs-gpios", NULL)) {
1574                 as->use_cs_gpios = false;
1575                 master->num_chipselect = 4;
1576         }
1577
1578         as->use_dma = false;
1579         as->use_pdc = false;
1580         if (as->caps.has_dma_support) {
1581                 ret = atmel_spi_configure_dma(as);
1582                 if (ret == 0)
1583                         as->use_dma = true;
1584                 else if (ret == -EPROBE_DEFER)
1585                         return ret;
1586         } else {
1587                 as->use_pdc = true;
1588         }
1589
1590         if (as->caps.has_dma_support && !as->use_dma)
1591                 dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
1592
1593         if (as->use_pdc) {
1594                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
1595                                         0, dev_name(&pdev->dev), master);
1596         } else {
1597                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
1598                                         0, dev_name(&pdev->dev), master);
1599         }
1600         if (ret)
1601                 goto out_unmap_regs;
1602
1603         /* Initialize the hardware */
1604         ret = clk_prepare_enable(clk);
1605         if (ret)
1606                 goto out_free_irq;
1607         spi_writel(as, CR, SPI_BIT(SWRST));
1608         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1609         if (as->caps.has_wdrbt) {
1610                 spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
1611                                 | SPI_BIT(MSTR));
1612         } else {
1613                 spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
1614         }
1615
1616         if (as->use_pdc)
1617                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1618         spi_writel(as, CR, SPI_BIT(SPIEN));
1619
1620         as->fifo_size = 0;
1621         if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
1622                                   &as->fifo_size)) {
1623                 dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size);
1624                 spi_writel(as, CR, SPI_BIT(FIFOEN));
1625         }
1626
1627         /* go! */
1628         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
1629                         (unsigned long)regs->start, irq);
1630
1631         pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
1632         pm_runtime_use_autosuspend(&pdev->dev);
1633         pm_runtime_set_active(&pdev->dev);
1634         pm_runtime_enable(&pdev->dev);
1635
1636         ret = devm_spi_register_master(&pdev->dev, master);
1637         if (ret)
1638                 goto out_free_dma;
1639
1640         return 0;
1641
1642 out_free_dma:
1643         pm_runtime_disable(&pdev->dev);
1644         pm_runtime_set_suspended(&pdev->dev);
1645
1646         if (as->use_dma)
1647                 atmel_spi_release_dma(as);
1648
1649         spi_writel(as, CR, SPI_BIT(SWRST));
1650         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1651         clk_disable_unprepare(clk);
1652 out_free_irq:
1653 out_unmap_regs:
1654 out_free_buffer:
1655         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1656                         as->buffer_dma);
1657 out_free:
1658         spi_master_put(master);
1659         return ret;
1660 }
1661
1662 static int atmel_spi_remove(struct platform_device *pdev)
1663 {
1664         struct spi_master       *master = platform_get_drvdata(pdev);
1665         struct atmel_spi        *as = spi_master_get_devdata(master);
1666
1667         pm_runtime_get_sync(&pdev->dev);
1668
1669         /* reset the hardware and block queue progress */
1670         spin_lock_irq(&as->lock);
1671         if (as->use_dma) {
1672                 atmel_spi_stop_dma(as);
1673                 atmel_spi_release_dma(as);
1674         }
1675
1676         spi_writel(as, CR, SPI_BIT(SWRST));
1677         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1678         spi_readl(as, SR);
1679         spin_unlock_irq(&as->lock);
1680
1681         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1682                         as->buffer_dma);
1683
1684         clk_disable_unprepare(as->clk);
1685
1686         pm_runtime_put_noidle(&pdev->dev);
1687         pm_runtime_disable(&pdev->dev);
1688
1689         return 0;
1690 }
1691
1692 #ifdef CONFIG_PM
1693 static int atmel_spi_runtime_suspend(struct device *dev)
1694 {
1695         struct spi_master *master = dev_get_drvdata(dev);
1696         struct atmel_spi *as = spi_master_get_devdata(master);
1697
1698         clk_disable_unprepare(as->clk);
1699         pinctrl_pm_select_sleep_state(dev);
1700
1701         return 0;
1702 }
1703
1704 static int atmel_spi_runtime_resume(struct device *dev)
1705 {
1706         struct spi_master *master = dev_get_drvdata(dev);
1707         struct atmel_spi *as = spi_master_get_devdata(master);
1708
1709         pinctrl_pm_select_default_state(dev);
1710
1711         return clk_prepare_enable(as->clk);
1712 }
1713
1714 #ifdef CONFIG_PM_SLEEP
1715 static int atmel_spi_suspend(struct device *dev)
1716 {
1717         struct spi_master *master = dev_get_drvdata(dev);
1718         int ret;
1719
1720         /* Stop the queue running */
1721         ret = spi_master_suspend(master);
1722         if (ret) {
1723                 dev_warn(dev, "cannot suspend master\n");
1724                 return ret;
1725         }
1726
1727         if (!pm_runtime_suspended(dev))
1728                 atmel_spi_runtime_suspend(dev);
1729
1730         return 0;
1731 }
1732
1733 static int atmel_spi_resume(struct device *dev)
1734 {
1735         struct spi_master *master = dev_get_drvdata(dev);
1736         int ret;
1737
1738         if (!pm_runtime_suspended(dev)) {
1739                 ret = atmel_spi_runtime_resume(dev);
1740                 if (ret)
1741                         return ret;
1742         }
1743
1744         /* Start the queue running */
1745         ret = spi_master_resume(master);
1746         if (ret)
1747                 dev_err(dev, "problem starting queue (%d)\n", ret);
1748
1749         return ret;
1750 }
1751 #endif
1752
1753 static const struct dev_pm_ops atmel_spi_pm_ops = {
1754         SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
1755         SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
1756                            atmel_spi_runtime_resume, NULL)
1757 };
1758 #define ATMEL_SPI_PM_OPS        (&atmel_spi_pm_ops)
1759 #else
1760 #define ATMEL_SPI_PM_OPS        NULL
1761 #endif
1762
1763 #if defined(CONFIG_OF)
1764 static const struct of_device_id atmel_spi_dt_ids[] = {
1765         { .compatible = "atmel,at91rm9200-spi" },
1766         { /* sentinel */ }
1767 };
1768
1769 MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
1770 #endif
1771
1772 static struct platform_driver atmel_spi_driver = {
1773         .driver         = {
1774                 .name   = "atmel_spi",
1775                 .pm     = ATMEL_SPI_PM_OPS,
1776                 .of_match_table = of_match_ptr(atmel_spi_dt_ids),
1777         },
1778         .probe          = atmel_spi_probe,
1779         .remove         = atmel_spi_remove,
1780 };
1781 module_platform_driver(atmel_spi_driver);
1782
1783 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
1784 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1785 MODULE_LICENSE("GPL");
1786 MODULE_ALIAS("platform:atmel_spi");