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/of_gpio.h>
  28 #include <linux/pinctrl/consumer.h>
  29 #include <linux/pm_runtime.h>
  30
  31 /* SPI register offsets */
  32 #define SPI_CR                                  0x0000
  33 #define SPI_MR                                  0x0004
  34 #define SPI_RDR                                 0x0008
  35 #define SPI_TDR                                 0x000c
  36 #define SPI_SR                                  0x0010
  37 #define SPI_IER                                 0x0014
  38 #define SPI_IDR                                 0x0018
  39 #define SPI_IMR                                 0x001c
  40 #define SPI_CSR0                                0x0030
  41 #define SPI_CSR1                                0x0034
  42 #define SPI_CSR2                                0x0038
  43 #define SPI_CSR3                                0x003c
  44 #define SPI_FMR                                 0x0040
  45 #define SPI_FLR                                 0x0044
  46 #define SPI_VERSION                             0x00fc
  47 #define SPI_RPR                                 0x0100
  48 #define SPI_RCR                                 0x0104
  49 #define SPI_TPR                                 0x0108
  50 #define SPI_TCR                                 0x010c
  51 #define SPI_RNPR                                0x0110
  52 #define SPI_RNCR                                0x0114
  53 #define SPI_TNPR                                0x0118
  54 #define SPI_TNCR                                0x011c
  55 #define SPI_PTCR                                0x0120
  56 #define SPI_PTSR                                0x0124
  57
  58 /* Bitfields in CR */
  59 #define SPI_SPIEN_OFFSET                        0
  60 #define SPI_SPIEN_SIZE                          1
  61 #define SPI_SPIDIS_OFFSET                       1
  62 #define SPI_SPIDIS_SIZE                         1
  63 #define SPI_SWRST_OFFSET                        7
  64 #define SPI_SWRST_SIZE                          1
  65 #define SPI_LASTXFER_OFFSET                     24
  66 #define SPI_LASTXFER_SIZE                       1
  67 #define SPI_TXFCLR_OFFSET                       16
  68 #define SPI_TXFCLR_SIZE                         1
  69 #define SPI_RXFCLR_OFFSET                       17
  70 #define SPI_RXFCLR_SIZE                         1
  71 #define SPI_FIFOEN_OFFSET                       30
  72 #define SPI_FIFOEN_SIZE                         1
  73 #define SPI_FIFODIS_OFFSET                      31
  74 #define SPI_FIFODIS_SIZE                        1
  75
  76 /* Bitfields in MR */
  77 #define SPI_MSTR_OFFSET                         0
  78 #define SPI_MSTR_SIZE                           1
  79 #define SPI_PS_OFFSET                           1
  80 #define SPI_PS_SIZE                             1
  81 #define SPI_PCSDEC_OFFSET                       2
  82 #define SPI_PCSDEC_SIZE                         1
  83 #define SPI_FDIV_OFFSET                         3
  84 #define SPI_FDIV_SIZE                           1
  85 #define SPI_MODFDIS_OFFSET                      4
  86 #define SPI_MODFDIS_SIZE                        1
  87 #define SPI_WDRBT_OFFSET                        5
  88 #define SPI_WDRBT_SIZE                          1
  89 #define SPI_LLB_OFFSET                          7
  90 #define SPI_LLB_SIZE                            1
  91 #define SPI_PCS_OFFSET                          16
  92 #define SPI_PCS_SIZE                            4
  93 #define SPI_DLYBCS_OFFSET                       24
  94 #define SPI_DLYBCS_SIZE                         8
  95
  96 /* Bitfields in RDR */
  97 #define SPI_RD_OFFSET                           0
  98 #define SPI_RD_SIZE                             16
  99
 100 /* Bitfields in TDR */
 101 #define SPI_TD_OFFSET                           0
 102 #define SPI_TD_SIZE                             16
 103
 104 /* Bitfields in SR */
 105 #define SPI_RDRF_OFFSET                         0
 106 #define SPI_RDRF_SIZE                           1
 107 #define SPI_TDRE_OFFSET                         1
 108 #define SPI_TDRE_SIZE                           1
 109 #define SPI_MODF_OFFSET                         2
 110 #define SPI_MODF_SIZE                           1
 111 #define SPI_OVRES_OFFSET                        3
 112 #define SPI_OVRES_SIZE                          1
 113 #define SPI_ENDRX_OFFSET                        4
 114 #define SPI_ENDRX_SIZE                          1
 115 #define SPI_ENDTX_OFFSET                        5
 116 #define SPI_ENDTX_SIZE                          1
 117 #define SPI_RXBUFF_OFFSET                       6
 118 #define SPI_RXBUFF_SIZE                         1
 119 #define SPI_TXBUFE_OFFSET                       7
 120 #define SPI_TXBUFE_SIZE                         1
 121 #define SPI_NSSR_OFFSET                         8
 122 #define SPI_NSSR_SIZE                           1
 123 #define SPI_TXEMPTY_OFFSET                      9
 124 #define SPI_TXEMPTY_SIZE                        1
 125 #define SPI_SPIENS_OFFSET                       16
 126 #define SPI_SPIENS_SIZE                         1
 127 #define SPI_TXFEF_OFFSET                        24
 128 #define SPI_TXFEF_SIZE                          1
 129 #define SPI_TXFFF_OFFSET                        25
 130 #define SPI_TXFFF_SIZE                          1
 131 #define SPI_TXFTHF_OFFSET                       26
 132 #define SPI_TXFTHF_SIZE                         1
 133 #define SPI_RXFEF_OFFSET                        27
 134 #define SPI_RXFEF_SIZE                          1
 135 #define SPI_RXFFF_OFFSET                        28
 136 #define SPI_RXFFF_SIZE                          1
 137 #define SPI_RXFTHF_OFFSET                       29
 138 #define SPI_RXFTHF_SIZE                         1
 139 #define SPI_TXFPTEF_OFFSET                      30
 140 #define SPI_TXFPTEF_SIZE                        1
 141 #define SPI_RXFPTEF_OFFSET                      31
 142 #define SPI_RXFPTEF_SIZE                        1
 143
 144 /* Bitfields in CSR0 */
 145 #define SPI_CPOL_OFFSET                         0
 146 #define SPI_CPOL_SIZE                           1
 147 #define SPI_NCPHA_OFFSET                        1
 148 #define SPI_NCPHA_SIZE                          1
 149 #define SPI_CSAAT_OFFSET                        3
 150 #define SPI_CSAAT_SIZE                          1
 151 #define SPI_BITS_OFFSET                         4
 152 #define SPI_BITS_SIZE                           4
 153 #define SPI_SCBR_OFFSET                         8
 154 #define SPI_SCBR_SIZE                           8
 155 #define SPI_DLYBS_OFFSET                        16
 156 #define SPI_DLYBS_SIZE                          8
 157 #define SPI_DLYBCT_OFFSET                       24
 158 #define SPI_DLYBCT_SIZE                         8
 159
 160 /* Bitfields in RCR */
 161 #define SPI_RXCTR_OFFSET                        0
 162 #define SPI_RXCTR_SIZE                          16
 163
 164 /* Bitfields in TCR */
 165 #define SPI_TXCTR_OFFSET                        0
 166 #define SPI_TXCTR_SIZE                          16
 167
 168 /* Bitfields in RNCR */
 169 #define SPI_RXNCR_OFFSET                        0
 170 #define SPI_RXNCR_SIZE                          16
 171
 172 /* Bitfields in TNCR */
 173 #define SPI_TXNCR_OFFSET                        0
 174 #define SPI_TXNCR_SIZE                          16
 175
 176 /* Bitfields in PTCR */
 177 #define SPI_RXTEN_OFFSET                        0
 178 #define SPI_RXTEN_SIZE                          1
 179 #define SPI_RXTDIS_OFFSET                       1
 180 #define SPI_RXTDIS_SIZE                         1
 181 #define SPI_TXTEN_OFFSET                        8
 182 #define SPI_TXTEN_SIZE                          1
 183 #define SPI_TXTDIS_OFFSET                       9
 184 #define SPI_TXTDIS_SIZE                         1
 185
 186 /* Bitfields in FMR */
 187 #define SPI_TXRDYM_OFFSET                       0
 188 #define SPI_TXRDYM_SIZE                         2
 189 #define SPI_RXRDYM_OFFSET                       4
 190 #define SPI_RXRDYM_SIZE                         2
 191 #define SPI_TXFTHRES_OFFSET                     16
 192 #define SPI_TXFTHRES_SIZE                       6
 193 #define SPI_RXFTHRES_OFFSET                     24
 194 #define SPI_RXFTHRES_SIZE                       6
 195
 196 /* Bitfields in FLR */
 197 #define SPI_TXFL_OFFSET                         0
 198 #define SPI_TXFL_SIZE                           6
 199 #define SPI_RXFL_OFFSET                         16
 200 #define SPI_RXFL_SIZE                           6
 201
 202 /* Constants for BITS */
 203 #define SPI_BITS_8_BPT                          0
 204 #define SPI_BITS_9_BPT                          1
 205 #define SPI_BITS_10_BPT                         2
 206 #define SPI_BITS_11_BPT                         3
 207 #define SPI_BITS_12_BPT                         4
 208 #define SPI_BITS_13_BPT                         5
 209 #define SPI_BITS_14_BPT                         6
 210 #define SPI_BITS_15_BPT                         7
 211 #define SPI_BITS_16_BPT                         8
 212 #define SPI_ONE_DATA                            0
 213 #define SPI_TWO_DATA                            1
 214 #define SPI_FOUR_DATA                           2
 215
 216 /* Bit manipulation macros */
 217 #define SPI_BIT(name) \
 218         (1 << SPI_##name##_OFFSET)
 219 #define SPI_BF(name, value) \
 220         (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
 221 #define SPI_BFEXT(name, value) \
 222         (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
 223 #define SPI_BFINS(name, value, old) \
 224         (((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
 225           | SPI_BF(name, value))
 226
 227 /* Register access macros */
 228 #ifdef CONFIG_AVR32
 229 #define spi_readl(port, reg) \
 230         __raw_readl((port)->regs + SPI_##reg)
 231 #define spi_writel(port, reg, value) \
 232         __raw_writel((value), (port)->regs + SPI_##reg)
 233
 234 #define spi_readw(port, reg) \
 235         __raw_readw((port)->regs + SPI_##reg)
 236 #define spi_writew(port, reg, value) \
 237         __raw_writew((value), (port)->regs + SPI_##reg)
 238
 239 #define spi_readb(port, reg) \
 240         __raw_readb((port)->regs + SPI_##reg)
 241 #define spi_writeb(port, reg, value) \
 242         __raw_writeb((value), (port)->regs + SPI_##reg)
 243 #else
 244 #define spi_readl(port, reg) \
 245         readl_relaxed((port)->regs + SPI_##reg)
 246 #define spi_writel(port, reg, value) \
 247         writel_relaxed((value), (port)->regs + SPI_##reg)
 248
 249 #define spi_readw(port, reg) \
 250         readw_relaxed((port)->regs + SPI_##reg)
 251 #define spi_writew(port, reg, value) \
 252         writew_relaxed((value), (port)->regs + SPI_##reg)
 253
 254 #define spi_readb(port, reg) \
 255         readb_relaxed((port)->regs + SPI_##reg)
 256 #define spi_writeb(port, reg, value) \
 257         writeb_relaxed((value), (port)->regs + SPI_##reg)
 258 #endif
 259 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
 260  * cache operations; better heuristics consider wordsize and bitrate.
 261  */
 262 #define DMA_MIN_BYTES   16
 263
 264 #define SPI_DMA_TIMEOUT         (msecs_to_jiffies(1000))
 265
 266 #define AUTOSUSPEND_TIMEOUT     2000
 267
 268 struct atmel_spi_caps {
 269         bool    is_spi2;
 270         bool    has_wdrbt;
 271         bool    has_dma_support;
 272         bool    has_pdc_support;
 273 };
 274
 275 /*
 276  * The core SPI transfer engine just talks to a register bank to set up
 277  * DMA transfers; transfer queue progress is driven by IRQs.  The clock
 278  * framework provides the base clock, subdivided for each spi_device.
 279  */
 280 struct atmel_spi {
 281         spinlock_t              lock;
 282         unsigned long           flags;
 283
 284         phys_addr_t             phybase;
 285         void __iomem            *regs;
 286         int                     irq;
 287         struct clk              *clk;
 288         struct platform_device  *pdev;
 289         unsigned long           spi_clk;
 290
 291         struct spi_transfer     *current_transfer;
 292         int                     current_remaining_bytes;
 293         int                     done_status;
 294
 295         struct completion       xfer_completion;
 296
 297         struct atmel_spi_caps   caps;
 298
 299         bool                    use_dma;
 300         bool                    use_pdc;
 301         bool                    use_cs_gpios;
 302
 303         bool                    keep_cs;
 304         bool                    cs_active;
 305
 306         u32                     fifo_size;
 307 };
 308
 309 /* Controller-specific per-slave state */
 310 struct atmel_spi_device {
 311         unsigned int            npcs_pin;
 312         u32                     csr;
 313 };
 314
 315 #define SPI_MAX_DMA_XFER        65535 /* true for both PDC and DMA */
 316 #define INVALID_DMA_ADDRESS     0xffffffff
 317
 318 /*
 319  * Version 2 of the SPI controller has
 320  *  - CR.LASTXFER
 321  *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
 322  *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
 323  *  - SPI_CSRx.CSAAT
 324  *  - SPI_CSRx.SBCR allows faster clocking
 325  */
 326 static bool atmel_spi_is_v2(struct atmel_spi *as)
 327 {
 328         return as->caps.is_spi2;
 329 }
 330
 331 /*
 332  * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
 333  * they assume that spi slave device state will not change on deselect, so
 334  * that automagic deselection is OK.  ("NPCSx rises if no data is to be
 335  * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
 336  * controllers have CSAAT and friends.
 337  *
 338  * Since the CSAAT functionality is a bit weird on newer controllers as
 339  * well, we use GPIO to control nCSx pins on all controllers, updating
 340  * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
 341  * support active-high chipselects despite the controller's belief that
 342  * only active-low devices/systems exists.
 343  *
 344  * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
 345  * right when driven with GPIO.  ("Mode Fault does not allow more than one
 346  * Master on Chip Select 0.")  No workaround exists for that ... so for
 347  * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
 348  * and (c) will trigger that first erratum in some cases.
 349  */
 350
 351 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 352 {
 353         struct atmel_spi_device *asd = spi->controller_state;
 354         unsigned active = spi->mode & SPI_CS_HIGH;
 355         u32 mr;
 356
 357         if (atmel_spi_is_v2(as)) {
 358                 spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
 359                 /* For the low SPI version, there is a issue that PDC transfer
 360                  * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
 361                  */
 362                 spi_writel(as, CSR0, asd->csr);
 363                 if (as->caps.has_wdrbt) {
 364                         spi_writel(as, MR,
 365                                         SPI_BF(PCS, ~(0x01 << spi->chip_select))
 366                                         | SPI_BIT(WDRBT)
 367                                         | SPI_BIT(MODFDIS)
 368                                         | SPI_BIT(MSTR));
 369                 } else {
 370                         spi_writel(as, MR,
 371                                         SPI_BF(PCS, ~(0x01 << spi->chip_select))
 372                                         | SPI_BIT(MODFDIS)
 373                                         | SPI_BIT(MSTR));
 374                 }
 375
 376                 mr = spi_readl(as, MR);
 377                 if (as->use_cs_gpios)
 378                         gpio_set_value(asd->npcs_pin, active);
 379         } else {
 380                 u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
 381                 int i;
 382                 u32 csr;
 383
 384                 /* Make sure clock polarity is correct */
 385                 for (i = 0; i < spi->master->num_chipselect; i++) {
 386                         csr = spi_readl(as, CSR0 + 4 * i);
 387                         if ((csr ^ cpol) & SPI_BIT(CPOL))
 388                                 spi_writel(as, CSR0 + 4 * i,
 389                                                 csr ^ SPI_BIT(CPOL));
 390                 }
 391
 392                 mr = spi_readl(as, MR);
 393                 mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
 394                 if (as->use_cs_gpios && spi->chip_select != 0)
 395                         gpio_set_value(asd->npcs_pin, active);
 396                 spi_writel(as, MR, mr);
 397         }
 398
 399         dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
 400                         asd->npcs_pin, active ? " (high)" : "",
 401                         mr);
 402 }
 403
 404 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 405 {
 406         struct atmel_spi_device *asd = spi->controller_state;
 407         unsigned active = spi->mode & SPI_CS_HIGH;
 408         u32 mr;
 409
 410         /* only deactivate *this* device; sometimes transfers to
 411          * another device may be active when this routine is called.
 412          */
 413         mr = spi_readl(as, MR);
 414         if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
 415                 mr = SPI_BFINS(PCS, 0xf, mr);
 416                 spi_writel(as, MR, mr);
 417         }
 418
 419         dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
 420                         asd->npcs_pin, active ? " (low)" : "",
 421                         mr);
 422
 423         if (!as->use_cs_gpios)
 424                 spi_writel(as, CR, SPI_BIT(LASTXFER));
 425         else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
 426                 gpio_set_value(asd->npcs_pin, !active);
 427 }
 428
 429 static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
 430 {
 431         spin_lock_irqsave(&as->lock, as->flags);
 432 }
 433
 434 static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock)
 435 {
 436         spin_unlock_irqrestore(&as->lock, as->flags);
 437 }
 438
 439 static inline bool atmel_spi_use_dma(struct atmel_spi *as,
 440                                 struct spi_transfer *xfer)
 441 {
 442         return as->use_dma && xfer->len >= DMA_MIN_BYTES;
 443 }
 444
 445 static bool atmel_spi_can_dma(struct spi_master *master,
 446                               struct spi_device *spi,
 447                               struct spi_transfer *xfer)
 448 {
 449         struct atmel_spi *as = spi_master_get_devdata(master);
 450
 451         return atmel_spi_use_dma(as, xfer);
 452 }
 453
 454 static int atmel_spi_dma_slave_config(struct atmel_spi *as,
 455                                 struct dma_slave_config *slave_config,
 456                                 u8 bits_per_word)
 457 {
 458         struct spi_master *master = platform_get_drvdata(as->pdev);
 459         int err = 0;
 460
 461         if (bits_per_word > 8) {
 462                 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 463                 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 464         } else {
 465                 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 466                 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 467         }
 468
 469         slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
 470         slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR;
 471         slave_config->src_maxburst = 1;
 472         slave_config->dst_maxburst = 1;
 473         slave_config->device_fc = false;
 474
 475         /*
 476          * This driver uses fixed peripheral select mode (PS bit set to '0' in
 477          * the Mode Register).
 478          * So according to the datasheet, when FIFOs are available (and
 479          * enabled), the Transmit FIFO operates in Multiple Data Mode.
 480          * In this mode, up to 2 data, not 4, can be written into the Transmit
 481          * Data Register in a single access.
 482          * However, the first data has to be written into the lowest 16 bits and
 483          * the second data into the highest 16 bits of the Transmit
 484          * Data Register. For 8bit data (the most frequent case), it would
 485          * require to rework tx_buf so each data would actualy fit 16 bits.
 486          * So we'd rather write only one data at the time. Hence the transmit
 487          * path works the same whether FIFOs are available (and enabled) or not.
 488          */
 489         slave_config->direction = DMA_MEM_TO_DEV;
 490         if (dmaengine_slave_config(master->dma_tx, slave_config)) {
 491                 dev_err(&as->pdev->dev,
 492                         "failed to configure tx dma channel\n");
 493                 err = -EINVAL;
 494         }
 495
 496         /*
 497          * This driver configures the spi controller for master mode (MSTR bit
 498          * set to '1' in the Mode Register).
 499          * So according to the datasheet, when FIFOs are available (and
 500          * enabled), the Receive FIFO operates in Single Data Mode.
 501          * So the receive path works the same whether FIFOs are available (and
 502          * enabled) or not.
 503          */
 504         slave_config->direction = DMA_DEV_TO_MEM;
 505         if (dmaengine_slave_config(master->dma_rx, slave_config)) {
 506                 dev_err(&as->pdev->dev,
 507                         "failed to configure rx dma channel\n");
 508                 err = -EINVAL;
 509         }
 510
 511         return err;
 512 }
 513
 514 static int atmel_spi_configure_dma(struct spi_master *master,
 515                                    struct atmel_spi *as)
 516 {
 517         struct dma_slave_config slave_config;
 518         struct device *dev = &as->pdev->dev;
 519         int err;
 520
 521         dma_cap_mask_t mask;
 522         dma_cap_zero(mask);
 523         dma_cap_set(DMA_SLAVE, mask);
 524
 525         master->dma_tx = dma_request_slave_channel_reason(dev, "tx");
 526         if (IS_ERR(master->dma_tx)) {
 527                 err = PTR_ERR(master->dma_tx);
 528                 if (err == -EPROBE_DEFER) {
 529                         dev_warn(dev, "no DMA channel available at the moment\n");
 530                         goto error_clear;
 531                 }
 532                 dev_err(dev,
 533                         "DMA TX channel not available, SPI unable to use DMA\n");
 534                 err = -EBUSY;
 535                 goto error_clear;
 536         }
 537
 538         /*
 539          * No reason to check EPROBE_DEFER here since we have already requested
 540          * tx channel. If it fails here, it's for another reason.
 541          */
 542         master->dma_rx = dma_request_slave_channel(dev, "rx");
 543
 544         if (!master->dma_rx) {
 545                 dev_err(dev,
 546                         "DMA RX channel not available, SPI unable to use DMA\n");
 547                 err = -EBUSY;
 548                 goto error;
 549         }
 550
 551         err = atmel_spi_dma_slave_config(as, &slave_config, 8);
 552         if (err)
 553                 goto error;
 554
 555         dev_info(&as->pdev->dev,
 556                         "Using %s (tx) and %s (rx) for DMA transfers\n",
 557                         dma_chan_name(master->dma_tx),
 558                         dma_chan_name(master->dma_rx));
 559
 560         return 0;
 561 error:
 562         if (master->dma_rx)
 563                 dma_release_channel(master->dma_rx);
 564         if (!IS_ERR(master->dma_tx))
 565                 dma_release_channel(master->dma_tx);
 566 error_clear:
 567         master->dma_tx = master->dma_rx = NULL;
 568         return err;
 569 }
 570
 571 static void atmel_spi_stop_dma(struct spi_master *master)
 572 {
 573         if (master->dma_rx)
 574                 dmaengine_terminate_all(master->dma_rx);
 575         if (master->dma_tx)
 576                 dmaengine_terminate_all(master->dma_tx);
 577 }
 578
 579 static void atmel_spi_release_dma(struct spi_master *master)
 580 {
 581         if (master->dma_rx) {
 582                 dma_release_channel(master->dma_rx);
 583                 master->dma_rx = NULL;
 584         }
 585         if (master->dma_tx) {
 586                 dma_release_channel(master->dma_tx);
 587                 master->dma_tx = NULL;
 588         }
 589 }
 590
 591 /* This function is called by the DMA driver from tasklet context */
 592 static void dma_callback(void *data)
 593 {
 594         struct spi_master       *master = data;
 595         struct atmel_spi        *as = spi_master_get_devdata(master);
 596
 597         complete(&as->xfer_completion);
 598 }
 599
 600 /*
 601  * Next transfer using PIO without FIFO.
 602  */
 603 static void atmel_spi_next_xfer_single(struct spi_master *master,
 604                                        struct spi_transfer *xfer)
 605 {
 606         struct atmel_spi        *as = spi_master_get_devdata(master);
 607         unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
 608
 609         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
 610
 611         /* Make sure data is not remaining in RDR */
 612         spi_readl(as, RDR);
 613         while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
 614                 spi_readl(as, RDR);
 615                 cpu_relax();
 616         }
 617
 618         if (xfer->bits_per_word > 8)
 619                 spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
 620         else
 621                 spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
 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->bits_per_word > 8) {
 669                         td0 = *words++;
 670                         td1 = *words++;
 671                 } else {
 672                         td0 = *bytes++;
 673                         td1 = *bytes++;
 674                 }
 675
 676                 spi_writel(as, TDR, (td1 << 16) | td0);
 677                 num_data -= 2;
 678         }
 679
 680         if (num_data) {
 681                 if (xfer->bits_per_word > 8)
 682                         td0 = *words++;
 683                 else
 684                         td0 = *bytes++;
 685
 686                 spi_writew(as, TDR, td0);
 687                 num_data--;
 688         }
 689
 690         dev_dbg(master->dev.parent,
 691                 "  start fifo xfer %p: len %u tx %p rx %p bitpw %d\n",
 692                 xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
 693                 xfer->bits_per_word);
 694
 695         /*
 696          * Enable RX FIFO Threshold Flag interrupt to be notified about
 697          * transfer completion.
 698          */
 699         spi_writel(as, IER, SPI_BIT(RXFTHF) | SPI_BIT(OVRES));
 700 }
 701
 702 /*
 703  * Next transfer using PIO.
 704  */
 705 static void atmel_spi_next_xfer_pio(struct spi_master *master,
 706                                     struct spi_transfer *xfer)
 707 {
 708         struct atmel_spi *as = spi_master_get_devdata(master);
 709
 710         if (as->fifo_size)
 711                 atmel_spi_next_xfer_fifo(master, xfer);
 712         else
 713                 atmel_spi_next_xfer_single(master, xfer);
 714 }
 715
 716 /*
 717  * Submit next transfer for DMA.
 718  */
 719 static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
 720                                 struct spi_transfer *xfer,
 721                                 u32 *plen)
 722 {
 723         struct atmel_spi        *as = spi_master_get_devdata(master);
 724         struct dma_chan         *rxchan = master->dma_rx;
 725         struct dma_chan         *txchan = master->dma_tx;
 726         struct dma_async_tx_descriptor *rxdesc;
 727         struct dma_async_tx_descriptor *txdesc;
 728         struct dma_slave_config slave_config;
 729         dma_cookie_t            cookie;
 730
 731         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
 732
 733         /* Check that the channels are available */
 734         if (!rxchan || !txchan)
 735                 return -ENODEV;
 736
 737         /* release lock for DMA operations */
 738         atmel_spi_unlock(as);
 739
 740         *plen = xfer->len;
 741
 742         if (atmel_spi_dma_slave_config(as, &slave_config,
 743                                        xfer->bits_per_word))
 744                 goto err_exit;
 745
 746         /* Send both scatterlists */
 747         rxdesc = dmaengine_prep_slave_sg(rxchan,
 748                                          xfer->rx_sg.sgl, xfer->rx_sg.nents,
 749                                          DMA_FROM_DEVICE,
 750                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 751         if (!rxdesc)
 752                 goto err_dma;
 753
 754         txdesc = dmaengine_prep_slave_sg(txchan,
 755                                          xfer->tx_sg.sgl, xfer->tx_sg.nents,
 756                                          DMA_TO_DEVICE,
 757                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 758         if (!txdesc)
 759                 goto err_dma;
 760
 761         dev_dbg(master->dev.parent,
 762                 "  start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 763                 xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
 764                 xfer->rx_buf, (unsigned long long)xfer->rx_dma);
 765
 766         /* Enable relevant interrupts */
 767         spi_writel(as, IER, SPI_BIT(OVRES));
 768
 769         /* Put the callback on the RX transfer only, that should finish last */
 770         rxdesc->callback = dma_callback;
 771         rxdesc->callback_param = master;
 772
 773         /* Submit and fire RX and TX with TX last so we're ready to read! */
 774         cookie = rxdesc->tx_submit(rxdesc);
 775         if (dma_submit_error(cookie))
 776                 goto err_dma;
 777         cookie = txdesc->tx_submit(txdesc);
 778         if (dma_submit_error(cookie))
 779                 goto err_dma;
 780         rxchan->device->device_issue_pending(rxchan);
 781         txchan->device->device_issue_pending(txchan);
 782
 783         /* take back lock */
 784         atmel_spi_lock(as);
 785         return 0;
 786
 787 err_dma:
 788         spi_writel(as, IDR, SPI_BIT(OVRES));
 789         atmel_spi_stop_dma(master);
 790 err_exit:
 791         atmel_spi_lock(as);
 792         return -ENOMEM;
 793 }
 794
 795 static void atmel_spi_next_xfer_data(struct spi_master *master,
 796                                 struct spi_transfer *xfer,
 797                                 dma_addr_t *tx_dma,
 798                                 dma_addr_t *rx_dma,
 799                                 u32 *plen)
 800 {
 801         *rx_dma = xfer->rx_dma + xfer->len - *plen;
 802         *tx_dma = xfer->tx_dma + xfer->len - *plen;
 803         if (*plen > master->max_dma_len)
 804                 *plen = master->max_dma_len;
 805 }
 806
 807 static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
 808                                     struct spi_device *spi,
 809                                     struct spi_transfer *xfer)
 810 {
 811         u32                     scbr, csr;
 812         unsigned long           bus_hz;
 813
 814         /* v1 chips start out at half the peripheral bus speed. */
 815         bus_hz = as->spi_clk;
 816         if (!atmel_spi_is_v2(as))
 817                 bus_hz /= 2;
 818
 819         /*
 820          * Calculate the lowest divider that satisfies the
 821          * constraint, assuming div32/fdiv/mbz == 0.
 822          */
 823         scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
 824
 825         /*
 826          * If the resulting divider doesn't fit into the
 827          * register bitfield, we can't satisfy the constraint.
 828          */
 829         if (scbr >= (1 << SPI_SCBR_SIZE)) {
 830                 dev_err(&spi->dev,
 831                         "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
 832                         xfer->speed_hz, scbr, bus_hz/255);
 833                 return -EINVAL;
 834         }
 835         if (scbr == 0) {
 836                 dev_err(&spi->dev,
 837                         "setup: %d Hz too high, scbr %u; max %ld Hz\n",
 838                         xfer->speed_hz, scbr, bus_hz);
 839                 return -EINVAL;
 840         }
 841         csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
 842         csr = SPI_BFINS(SCBR, scbr, csr);
 843         spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 844
 845         return 0;
 846 }
 847
 848 /*
 849  * Submit next transfer for PDC.
 850  * lock is held, spi irq is blocked
 851  */
 852 static void atmel_spi_pdc_next_xfer(struct spi_master *master,
 853                                         struct spi_message *msg,
 854                                         struct spi_transfer *xfer)
 855 {
 856         struct atmel_spi        *as = spi_master_get_devdata(master);
 857         u32                     len;
 858         dma_addr_t              tx_dma, rx_dma;
 859
 860         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 861
 862         len = as->current_remaining_bytes;
 863         atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 864         as->current_remaining_bytes -= len;
 865
 866         spi_writel(as, RPR, rx_dma);
 867         spi_writel(as, TPR, tx_dma);
 868
 869         if (msg->spi->bits_per_word > 8)
 870                 len >>= 1;
 871         spi_writel(as, RCR, len);
 872         spi_writel(as, TCR, len);
 873
 874         dev_dbg(&msg->spi->dev,
 875                 "  start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 876                 xfer, xfer->len, xfer->tx_buf,
 877                 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
 878                 (unsigned long long)xfer->rx_dma);
 879
 880         if (as->current_remaining_bytes) {
 881                 len = as->current_remaining_bytes;
 882                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
 883                 as->current_remaining_bytes -= len;
 884
 885                 spi_writel(as, RNPR, rx_dma);
 886                 spi_writel(as, TNPR, tx_dma);
 887
 888                 if (msg->spi->bits_per_word > 8)
 889                         len >>= 1;
 890                 spi_writel(as, RNCR, len);
 891                 spi_writel(as, TNCR, len);
 892
 893                 dev_dbg(&msg->spi->dev,
 894                         "  next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
 895                         xfer, xfer->len, xfer->tx_buf,
 896                         (unsigned long long)xfer->tx_dma, xfer->rx_buf,
 897                         (unsigned long long)xfer->rx_dma);
 898         }
 899
 900         /* REVISIT: We're waiting for RXBUFF before we start the next
 901          * transfer because we need to handle some difficult timing
 902          * issues otherwise. If we wait for TXBUFE in one transfer and
 903          * then starts waiting for RXBUFF in the next, it's difficult
 904          * to tell the difference between the RXBUFF interrupt we're
 905          * actually waiting for and the RXBUFF interrupt of the
 906          * previous transfer.
 907          *
 908          * It should be doable, though. Just not now...
 909          */
 910         spi_writel(as, IER, SPI_BIT(RXBUFF) | SPI_BIT(OVRES));
 911         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 912 }
 913
 914 /*
 915  * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
 916  *  - The buffer is either valid for CPU access, else NULL
 917  *  - If the buffer is valid, so is its DMA address
 918  *
 919  * This driver manages the dma address unless message->is_dma_mapped.
 920  */
 921 static int
 922 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 923 {
 924         struct device   *dev = &as->pdev->dev;
 925
 926         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 927         if (xfer->tx_buf) {
 928                 /* tx_buf is a const void* where we need a void * for the dma
 929                  * mapping */
 930                 void *nonconst_tx = (void *)xfer->tx_buf;
 931
 932                 xfer->tx_dma = dma_map_single(dev,
 933                                 nonconst_tx, xfer->len,
 934                                 DMA_TO_DEVICE);
 935                 if (dma_mapping_error(dev, xfer->tx_dma))
 936                         return -ENOMEM;
 937         }
 938         if (xfer->rx_buf) {
 939                 xfer->rx_dma = dma_map_single(dev,
 940                                 xfer->rx_buf, xfer->len,
 941                                 DMA_FROM_DEVICE);
 942                 if (dma_mapping_error(dev, xfer->rx_dma)) {
 943                         if (xfer->tx_buf)
 944                                 dma_unmap_single(dev,
 945                                                 xfer->tx_dma, xfer->len,
 946                                                 DMA_TO_DEVICE);
 947                         return -ENOMEM;
 948                 }
 949         }
 950         return 0;
 951 }
 952
 953 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
 954                                      struct spi_transfer *xfer)
 955 {
 956         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
 957                 dma_unmap_single(master->dev.parent, xfer->tx_dma,
 958                                  xfer->len, DMA_TO_DEVICE);
 959         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
 960                 dma_unmap_single(master->dev.parent, xfer->rx_dma,
 961                                  xfer->len, DMA_FROM_DEVICE);
 962 }
 963
 964 static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
 965 {
 966         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 967 }
 968
 969 static void
 970 atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer)
 971 {
 972         u8              *rxp;
 973         u16             *rxp16;
 974         unsigned long   xfer_pos = xfer->len - as->current_remaining_bytes;
 975
 976         if (xfer->bits_per_word > 8) {
 977                 rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
 978                 *rxp16 = spi_readl(as, RDR);
 979         } else {
 980                 rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
 981                 *rxp = spi_readl(as, RDR);
 982         }
 983         if (xfer->bits_per_word > 8) {
 984                 if (as->current_remaining_bytes > 2)
 985                         as->current_remaining_bytes -= 2;
 986                 else
 987                         as->current_remaining_bytes = 0;
 988         } else {
 989                 as->current_remaining_bytes--;
 990         }
 991 }
 992
 993 static void
 994 atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer)
 995 {
 996         u32 fifolr = spi_readl(as, FLR);
 997         u32 num_bytes, num_data = SPI_BFEXT(RXFL, fifolr);
 998         u32 offset = xfer->len - as->current_remaining_bytes;
 999         u16 *words = (u16 *)((u8 *)xfer->rx_buf + offset);
1000         u8  *bytes = (u8  *)((u8 *)xfer->rx_buf + offset);
1001         u16 rd; /* RD field is the lowest 16 bits of RDR */
1002
1003         /* Update the number of remaining bytes to transfer */
1004         num_bytes = ((xfer->bits_per_word > 8) ?
1005                      (num_data << 1) :
1006                      num_data);
1007
1008         if (as->current_remaining_bytes > num_bytes)
1009                 as->current_remaining_bytes -= num_bytes;
1010         else
1011                 as->current_remaining_bytes = 0;
1012
1013         /* Handle odd number of bytes when data are more than 8bit width */
1014         if (xfer->bits_per_word > 8)
1015                 as->current_remaining_bytes &= ~0x1;
1016
1017         /* Read data */
1018         while (num_data) {
1019                 rd = spi_readl(as, RDR);
1020                 if (xfer->bits_per_word > 8)
1021                         *words++ = rd;
1022                 else
1023                         *bytes++ = rd;
1024                 num_data--;
1025         }
1026 }
1027
1028 /* Called from IRQ
1029  *
1030  * Must update "current_remaining_bytes" to keep track of data
1031  * to transfer.
1032  */
1033 static void
1034 atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
1035 {
1036         if (as->fifo_size)
1037                 atmel_spi_pump_fifo_data(as, xfer);
1038         else
1039                 atmel_spi_pump_single_data(as, xfer);
1040 }
1041
1042 /* Interrupt
1043  *
1044  * No need for locking in this Interrupt handler: done_status is the
1045  * only information modified.
1046  */
1047 static irqreturn_t
1048 atmel_spi_pio_interrupt(int irq, void *dev_id)
1049 {
1050         struct spi_master       *master = dev_id;
1051         struct atmel_spi        *as = spi_master_get_devdata(master);
1052         u32                     status, pending, imr;
1053         struct spi_transfer     *xfer;
1054         int                     ret = IRQ_NONE;
1055
1056         imr = spi_readl(as, IMR);
1057         status = spi_readl(as, SR);
1058         pending = status & imr;
1059
1060         if (pending & SPI_BIT(OVRES)) {
1061                 ret = IRQ_HANDLED;
1062                 spi_writel(as, IDR, SPI_BIT(OVRES));
1063                 dev_warn(master->dev.parent, "overrun\n");
1064
1065                 /*
1066                  * When we get an overrun, we disregard the current
1067                  * transfer. Data will not be copied back from any
1068                  * bounce buffer and msg->actual_len will not be
1069                  * updated with the last xfer.
1070                  *
1071                  * We will also not process any remaning transfers in
1072                  * the message.
1073                  */
1074                 as->done_status = -EIO;
1075                 smp_wmb();
1076
1077                 /* Clear any overrun happening while cleaning up */
1078                 spi_readl(as, SR);
1079
1080                 complete(&as->xfer_completion);
1081
1082         } else if (pending & (SPI_BIT(RDRF) | SPI_BIT(RXFTHF))) {
1083                 atmel_spi_lock(as);
1084
1085                 if (as->current_remaining_bytes) {
1086                         ret = IRQ_HANDLED;
1087                         xfer = as->current_transfer;
1088                         atmel_spi_pump_pio_data(as, xfer);
1089                         if (!as->current_remaining_bytes)
1090                                 spi_writel(as, IDR, pending);
1091
1092                         complete(&as->xfer_completion);
1093                 }
1094
1095                 atmel_spi_unlock(as);
1096         } else {
1097                 WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
1098                 ret = IRQ_HANDLED;
1099                 spi_writel(as, IDR, pending);
1100         }
1101
1102         return ret;
1103 }
1104
1105 static irqreturn_t
1106 atmel_spi_pdc_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         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
1119                 ret = IRQ_HANDLED;
1120
1121                 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
1122                                      | SPI_BIT(OVRES)));
1123
1124                 /* Clear any overrun happening while cleaning up */
1125                 spi_readl(as, SR);
1126
1127                 as->done_status = -EIO;
1128
1129                 complete(&as->xfer_completion);
1130
1131         } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
1132                 ret = IRQ_HANDLED;
1133
1134                 spi_writel(as, IDR, pending);
1135
1136                 complete(&as->xfer_completion);
1137         }
1138
1139         return ret;
1140 }
1141
1142 static int atmel_spi_setup(struct spi_device *spi)
1143 {
1144         struct atmel_spi        *as;
1145         struct atmel_spi_device *asd;
1146         u32                     csr;
1147         unsigned int            bits = spi->bits_per_word;
1148         unsigned int            npcs_pin;
1149
1150         as = spi_master_get_devdata(spi->master);
1151
1152         /* see notes above re chipselect */
1153         if (!atmel_spi_is_v2(as)
1154                         && spi->chip_select == 0
1155                         && (spi->mode & SPI_CS_HIGH)) {
1156                 dev_dbg(&spi->dev, "setup: can't be active-high\n");
1157                 return -EINVAL;
1158         }
1159
1160         csr = SPI_BF(BITS, bits - 8);
1161         if (spi->mode & SPI_CPOL)
1162                 csr |= SPI_BIT(CPOL);
1163         if (!(spi->mode & SPI_CPHA))
1164                 csr |= SPI_BIT(NCPHA);
1165         if (!as->use_cs_gpios)
1166                 csr |= SPI_BIT(CSAAT);
1167
1168         /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
1169          *
1170          * DLYBCT would add delays between words, slowing down transfers.
1171          * It could potentially be useful to cope with DMA bottlenecks, but
1172          * in those cases it's probably best to just use a lower bitrate.
1173          */
1174         csr |= SPI_BF(DLYBS, 0);
1175         csr |= SPI_BF(DLYBCT, 0);
1176
1177         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
1178         npcs_pin = (unsigned long)spi->controller_data;
1179
1180         if (!as->use_cs_gpios)
1181                 npcs_pin = spi->chip_select;
1182         else if (gpio_is_valid(spi->cs_gpio))
1183                 npcs_pin = spi->cs_gpio;
1184
1185         asd = spi->controller_state;
1186         if (!asd) {
1187                 asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
1188                 if (!asd)
1189                         return -ENOMEM;
1190
1191                 if (as->use_cs_gpios)
1192                         gpio_direction_output(npcs_pin,
1193                                               !(spi->mode & SPI_CS_HIGH));
1194
1195                 asd->npcs_pin = npcs_pin;
1196                 spi->controller_state = asd;
1197         }
1198
1199         asd->csr = csr;
1200
1201         dev_dbg(&spi->dev,
1202                 "setup: bpw %u mode 0x%x -> csr%d %08x\n",
1203                 bits, spi->mode, spi->chip_select, csr);
1204
1205         if (!atmel_spi_is_v2(as))
1206                 spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
1207
1208         return 0;
1209 }
1210
1211 static int atmel_spi_one_transfer(struct spi_master *master,
1212                                         struct spi_message *msg,
1213                                         struct spi_transfer *xfer)
1214 {
1215         struct atmel_spi        *as;
1216         struct spi_device       *spi = msg->spi;
1217         u8                      bits;
1218         u32                     len;
1219         struct atmel_spi_device *asd;
1220         int                     timeout;
1221         int                     ret;
1222         unsigned long           dma_timeout;
1223
1224         as = spi_master_get_devdata(master);
1225
1226         if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1227                 dev_dbg(&spi->dev, "missing rx or tx buf\n");
1228                 return -EINVAL;
1229         }
1230
1231         asd = spi->controller_state;
1232         bits = (asd->csr >> 4) & 0xf;
1233         if (bits != xfer->bits_per_word - 8) {
1234                 dev_dbg(&spi->dev,
1235                         "you can't yet change bits_per_word in transfers\n");
1236                 return -ENOPROTOOPT;
1237         }
1238
1239         /*
1240          * DMA map early, for performance (empties dcache ASAP) and
1241          * better fault reporting.
1242          */
1243         if ((!msg->is_dma_mapped)
1244                 && as->use_pdc) {
1245                 if (atmel_spi_dma_map_xfer(as, xfer) < 0)
1246                         return -ENOMEM;
1247         }
1248
1249         atmel_spi_set_xfer_speed(as, msg->spi, xfer);
1250
1251         as->done_status = 0;
1252         as->current_transfer = xfer;
1253         as->current_remaining_bytes = xfer->len;
1254         while (as->current_remaining_bytes) {
1255                 reinit_completion(&as->xfer_completion);
1256
1257                 if (as->use_pdc) {
1258                         atmel_spi_pdc_next_xfer(master, msg, xfer);
1259                 } else if (atmel_spi_use_dma(as, xfer)) {
1260                         len = as->current_remaining_bytes;
1261                         ret = atmel_spi_next_xfer_dma_submit(master,
1262                                                                 xfer, &len);
1263                         if (ret) {
1264                                 dev_err(&spi->dev,
1265                                         "unable to use DMA, fallback to PIO\n");
1266                                 atmel_spi_next_xfer_pio(master, xfer);
1267                         } else {
1268                                 as->current_remaining_bytes -= len;
1269                                 if (as->current_remaining_bytes < 0)
1270                                         as->current_remaining_bytes = 0;
1271                         }
1272                 } else {
1273                         atmel_spi_next_xfer_pio(master, xfer);
1274                 }
1275
1276                 /* interrupts are disabled, so free the lock for schedule */
1277                 atmel_spi_unlock(as);
1278                 dma_timeout = wait_for_completion_timeout(&as->xfer_completion,
1279                                                           SPI_DMA_TIMEOUT);
1280                 atmel_spi_lock(as);
1281                 if (WARN_ON(dma_timeout == 0)) {
1282                         dev_err(&spi->dev, "spi transfer timeout\n");
1283                         as->done_status = -EIO;
1284                 }
1285
1286                 if (as->done_status)
1287                         break;
1288         }
1289
1290         if (as->done_status) {
1291                 if (as->use_pdc) {
1292                         dev_warn(master->dev.parent,
1293                                 "overrun (%u/%u remaining)\n",
1294                                 spi_readl(as, TCR), spi_readl(as, RCR));
1295
1296                         /*
1297                          * Clean up DMA registers and make sure the data
1298                          * registers are empty.
1299                          */
1300                         spi_writel(as, RNCR, 0);
1301                         spi_writel(as, TNCR, 0);
1302                         spi_writel(as, RCR, 0);
1303                         spi_writel(as, TCR, 0);
1304                         for (timeout = 1000; timeout; timeout--)
1305                                 if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
1306                                         break;
1307                         if (!timeout)
1308                                 dev_warn(master->dev.parent,
1309                                          "timeout waiting for TXEMPTY");
1310                         while (spi_readl(as, SR) & SPI_BIT(RDRF))
1311                                 spi_readl(as, RDR);
1312
1313                         /* Clear any overrun happening while cleaning up */
1314                         spi_readl(as, SR);
1315
1316                 } else if (atmel_spi_use_dma(as, xfer)) {
1317                         atmel_spi_stop_dma(master);
1318                 }
1319
1320                 if (!msg->is_dma_mapped
1321                         && as->use_pdc)
1322                         atmel_spi_dma_unmap_xfer(master, xfer);
1323
1324                 return 0;
1325
1326         } else {
1327                 /* only update length if no error */
1328                 msg->actual_length += xfer->len;
1329         }
1330
1331         if (!msg->is_dma_mapped
1332                 && as->use_pdc)
1333                 atmel_spi_dma_unmap_xfer(master, xfer);
1334
1335         if (xfer->delay_usecs)
1336                 udelay(xfer->delay_usecs);
1337
1338         if (xfer->cs_change) {
1339                 if (list_is_last(&xfer->transfer_list,
1340                                  &msg->transfers)) {
1341                         as->keep_cs = true;
1342                 } else {
1343                         as->cs_active = !as->cs_active;
1344                         if (as->cs_active)
1345                                 cs_activate(as, msg->spi);
1346                         else
1347                                 cs_deactivate(as, msg->spi);
1348                 }
1349         }
1350
1351         return 0;
1352 }
1353
1354 static int atmel_spi_transfer_one_message(struct spi_master *master,
1355                                                 struct spi_message *msg)
1356 {
1357         struct atmel_spi *as;
1358         struct spi_transfer *xfer;
1359         struct spi_device *spi = msg->spi;
1360         int ret = 0;
1361
1362         as = spi_master_get_devdata(master);
1363
1364         dev_dbg(&spi->dev, "new message %p submitted for %s\n",
1365                                         msg, dev_name(&spi->dev));
1366
1367         atmel_spi_lock(as);
1368         cs_activate(as, spi);
1369
1370         as->cs_active = true;
1371         as->keep_cs = false;
1372
1373         msg->status = 0;
1374         msg->actual_length = 0;
1375
1376         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1377                 ret = atmel_spi_one_transfer(master, msg, xfer);
1378                 if (ret)
1379                         goto msg_done;
1380         }
1381
1382         if (as->use_pdc)
1383                 atmel_spi_disable_pdc_transfer(as);
1384
1385         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1386                 dev_dbg(&spi->dev,
1387                         "  xfer %p: len %u tx %p/%pad rx %p/%pad\n",
1388                         xfer, xfer->len,
1389                         xfer->tx_buf, &xfer->tx_dma,
1390                         xfer->rx_buf, &xfer->rx_dma);
1391         }
1392
1393 msg_done:
1394         if (!as->keep_cs)
1395                 cs_deactivate(as, msg->spi);
1396
1397         atmel_spi_unlock(as);
1398
1399         msg->status = as->done_status;
1400         spi_finalize_current_message(spi->master);
1401
1402         return ret;
1403 }
1404
1405 static void atmel_spi_cleanup(struct spi_device *spi)
1406 {
1407         struct atmel_spi_device *asd = spi->controller_state;
1408
1409         if (!asd)
1410                 return;
1411
1412         spi->controller_state = NULL;
1413         kfree(asd);
1414 }
1415
1416 static inline unsigned int atmel_get_version(struct atmel_spi *as)
1417 {
1418         return spi_readl(as, VERSION) & 0x00000fff;
1419 }
1420
1421 static void atmel_get_caps(struct atmel_spi *as)
1422 {
1423         unsigned int version;
1424
1425         version = atmel_get_version(as);
1426         dev_info(&as->pdev->dev, "version: 0x%x\n", version);
1427
1428         as->caps.is_spi2 = version > 0x121;
1429         as->caps.has_wdrbt = version >= 0x210;
1430 #ifdef CONFIG_SOC_SAM_V4_V5
1431         /*
1432          * Atmel SoCs based on ARM9 (SAM9x) cores should not use spi_map_buf()
1433          * since this later function tries to map buffers with dma_map_sg()
1434          * even if they have not been allocated inside DMA-safe areas.
1435          * On SoCs based on Cortex A5 (SAMA5Dx), it works anyway because for
1436          * those ARM cores, the data cache follows the PIPT model.
1437          * Also the L2 cache controller of SAMA5D2 uses the PIPT model too.
1438          * In case of PIPT caches, there cannot be cache aliases.
1439          * However on ARM9 cores, the data cache follows the VIVT model, hence
1440          * the cache aliases issue can occur when buffers are allocated from
1441          * DMA-unsafe areas, by vmalloc() for instance, where cache coherency is
1442          * not taken into account or at least not handled completely (cache
1443          * lines of aliases are not invalidated).
1444          * This is not a theorical issue: it was reproduced when trying to mount
1445          * a UBI file-system on a at91sam9g35ek board.
1446          */
1447         as->caps.has_dma_support = false;
1448 #else
1449         as->caps.has_dma_support = version >= 0x212;
1450 #endif
1451         as->caps.has_pdc_support = version < 0x212;
1452 }
1453
1454 /*-------------------------------------------------------------------------*/
1455 static int atmel_spi_gpio_cs(struct platform_device *pdev)
1456 {
1457         struct spi_master       *master = platform_get_drvdata(pdev);
1458         struct atmel_spi        *as = spi_master_get_devdata(master);
1459         struct device_node      *np = master->dev.of_node;
1460         int                     i;
1461         int                     ret = 0;
1462         int                     nb = 0;
1463
1464         if (!as->use_cs_gpios)
1465                 return 0;
1466
1467         if (!np)
1468                 return 0;
1469
1470         nb = of_gpio_named_count(np, "cs-gpios");
1471         for (i = 0; i < nb; i++) {
1472                 int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
1473                                                 "cs-gpios", i);
1474
1475                 if (cs_gpio == -EPROBE_DEFER)
1476                         return cs_gpio;
1477
1478                 if (gpio_is_valid(cs_gpio)) {
1479                         ret = devm_gpio_request(&pdev->dev, cs_gpio,
1480                                                 dev_name(&pdev->dev));
1481                         if (ret)
1482                                 return ret;
1483                 }
1484         }
1485
1486         return 0;
1487 }
1488
1489 static void atmel_spi_init(struct atmel_spi *as)
1490 {
1491         spi_writel(as, CR, SPI_BIT(SWRST));
1492         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1493         if (as->caps.has_wdrbt) {
1494                 spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
1495                                 | SPI_BIT(MSTR));
1496         } else {
1497                 spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
1498         }
1499
1500         if (as->use_pdc)
1501                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1502         spi_writel(as, CR, SPI_BIT(SPIEN));
1503
1504         if (as->fifo_size)
1505                 spi_writel(as, CR, SPI_BIT(FIFOEN));
1506 }
1507
1508 static int atmel_spi_probe(struct platform_device *pdev)
1509 {
1510         struct resource         *regs;
1511         int                     irq;
1512         struct clk              *clk;
1513         int                     ret;
1514         struct spi_master       *master;
1515         struct atmel_spi        *as;
1516
1517         /* Select default pin state */
1518         pinctrl_pm_select_default_state(&pdev->dev);
1519
1520         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1521         if (!regs)
1522                 return -ENXIO;
1523
1524         irq = platform_get_irq(pdev, 0);
1525         if (irq < 0)
1526                 return irq;
1527
1528         clk = devm_clk_get(&pdev->dev, "spi_clk");
1529         if (IS_ERR(clk))
1530                 return PTR_ERR(clk);
1531
1532         /* setup spi core then atmel-specific driver state */
1533         ret = -ENOMEM;
1534         master = spi_alloc_master(&pdev->dev, sizeof(*as));
1535         if (!master)
1536                 goto out_free;
1537
1538         /* the spi->mode bits understood by this driver: */
1539         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1540         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
1541         master->dev.of_node = pdev->dev.of_node;
1542         master->bus_num = pdev->id;
1543         master->num_chipselect = master->dev.of_node ? 0 : 4;
1544         master->setup = atmel_spi_setup;
1545         master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
1546         master->transfer_one_message = atmel_spi_transfer_one_message;
1547         master->cleanup = atmel_spi_cleanup;
1548         master->auto_runtime_pm = true;
1549         master->max_dma_len = SPI_MAX_DMA_XFER;
1550         master->can_dma = atmel_spi_can_dma;
1551         platform_set_drvdata(pdev, master);
1552
1553         as = spi_master_get_devdata(master);
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_unmap_regs;
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             pdev->dev.of_node &&
1574             !of_get_property(pdev->dev.of_node, "cs-gpios", NULL)) {
1575                 as->use_cs_gpios = false;
1576                 master->num_chipselect = 4;
1577         }
1578
1579         ret = atmel_spi_gpio_cs(pdev);
1580         if (ret)
1581                 goto out_unmap_regs;
1582
1583         as->use_dma = false;
1584         as->use_pdc = false;
1585         if (as->caps.has_dma_support) {
1586                 ret = atmel_spi_configure_dma(master, as);
1587                 if (ret == 0) {
1588                         as->use_dma = true;
1589                 } else if (ret == -EPROBE_DEFER) {
1590                         return ret;
1591                 }
1592         } else if (as->caps.has_pdc_support) {
1593                 as->use_pdc = true;
1594         }
1595
1596         if (as->caps.has_dma_support && !as->use_dma)
1597                 dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
1598
1599         if (as->use_pdc) {
1600                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
1601                                         0, dev_name(&pdev->dev), master);
1602         } else {
1603                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
1604                                         0, dev_name(&pdev->dev), master);
1605         }
1606         if (ret)
1607                 goto out_unmap_regs;
1608
1609         /* Initialize the hardware */
1610         ret = clk_prepare_enable(clk);
1611         if (ret)
1612                 goto out_free_irq;
1613
1614         as->spi_clk = clk_get_rate(clk);
1615
1616         as->fifo_size = 0;
1617         if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
1618                                   &as->fifo_size)) {
1619                 dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size);
1620         }
1621
1622         atmel_spi_init(as);
1623
1624         pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
1625         pm_runtime_use_autosuspend(&pdev->dev);
1626         pm_runtime_set_active(&pdev->dev);
1627         pm_runtime_enable(&pdev->dev);
1628
1629         ret = devm_spi_register_master(&pdev->dev, master);
1630         if (ret)
1631                 goto out_free_dma;
1632
1633         /* go! */
1634         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
1635                         (unsigned long)regs->start, irq);
1636
1637         return 0;
1638
1639 out_free_dma:
1640         pm_runtime_disable(&pdev->dev);
1641         pm_runtime_set_suspended(&pdev->dev);
1642
1643         if (as->use_dma)
1644                 atmel_spi_release_dma(master);
1645
1646         spi_writel(as, CR, SPI_BIT(SWRST));
1647         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1648         clk_disable_unprepare(clk);
1649 out_free_irq:
1650 out_unmap_regs:
1651 out_free:
1652         spi_master_put(master);
1653         return ret;
1654 }
1655
1656 static int atmel_spi_remove(struct platform_device *pdev)
1657 {
1658         struct spi_master       *master = platform_get_drvdata(pdev);
1659         struct atmel_spi        *as = spi_master_get_devdata(master);
1660
1661         pm_runtime_get_sync(&pdev->dev);
1662
1663         /* reset the hardware and block queue progress */
1664         spin_lock_irq(&as->lock);
1665         if (as->use_dma) {
1666                 atmel_spi_stop_dma(master);
1667                 atmel_spi_release_dma(master);
1668         }
1669
1670         spi_writel(as, CR, SPI_BIT(SWRST));
1671         spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1672         spi_readl(as, SR);
1673         spin_unlock_irq(&as->lock);
1674
1675         clk_disable_unprepare(as->clk);
1676
1677         pm_runtime_put_noidle(&pdev->dev);
1678         pm_runtime_disable(&pdev->dev);
1679
1680         return 0;
1681 }
1682
1683 #ifdef CONFIG_PM
1684 static int atmel_spi_runtime_suspend(struct device *dev)
1685 {
1686         struct spi_master *master = dev_get_drvdata(dev);
1687         struct atmel_spi *as = spi_master_get_devdata(master);
1688
1689         clk_disable_unprepare(as->clk);
1690         pinctrl_pm_select_sleep_state(dev);
1691
1692         return 0;
1693 }
1694
1695 static int atmel_spi_runtime_resume(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         pinctrl_pm_select_default_state(dev);
1701
1702         return clk_prepare_enable(as->clk);
1703 }
1704
1705 #ifdef CONFIG_PM_SLEEP
1706 static int atmel_spi_suspend(struct device *dev)
1707 {
1708         struct spi_master *master = dev_get_drvdata(dev);
1709         int ret;
1710
1711         /* Stop the queue running */
1712         ret = spi_master_suspend(master);
1713         if (ret) {
1714                 dev_warn(dev, "cannot suspend master\n");
1715                 return ret;
1716         }
1717
1718         if (!pm_runtime_suspended(dev))
1719                 atmel_spi_runtime_suspend(dev);
1720
1721         return 0;
1722 }
1723
1724 static int atmel_spi_resume(struct device *dev)
1725 {
1726         struct spi_master *master = dev_get_drvdata(dev);
1727         struct atmel_spi *as = spi_master_get_devdata(master);
1728         int ret;
1729
1730         ret = clk_prepare_enable(as->clk);
1731         if (ret)
1732                 return ret;
1733
1734         atmel_spi_init(as);
1735
1736         clk_disable_unprepare(as->clk);
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");