drivers/spi/spi-au1550.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * au1550 psc spi controller driver
   4  * may work also with au1200, au1210, au1250
   5  * will not work on au1000, au1100 and au1500 (no full spi controller there)
   6  *
   7  * Copyright (c) 2006 ATRON electronic GmbH
   8  * Author: Jan Nikitenko <jan.nikitenko@gmail.com>
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/slab.h>
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/device.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/resource.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi_bitbang.h>
  21 #include <linux/dma-mapping.h>
  22 #include <linux/completion.h>
  23 #include <asm/mach-au1x00/au1000.h>
  24 #include <asm/mach-au1x00/au1xxx_psc.h>
  25 #include <asm/mach-au1x00/au1xxx_dbdma.h>
  26
  27 #include <asm/mach-au1x00/au1550_spi.h>
  28
  29 static unsigned int usedma = 1;
  30 module_param(usedma, uint, 0644);
  31
  32 /*
  33 #define AU1550_SPI_DEBUG_LOOPBACK
  34 */
  35
  36
  37 #define AU1550_SPI_DBDMA_DESCRIPTORS 1
  38 #define AU1550_SPI_DMA_RXTMP_MINSIZE 2048U
  39
  40 struct au1550_spi {
  41         struct spi_bitbang bitbang;
  42
  43         volatile psc_spi_t __iomem *regs;
  44         int irq;
  45
  46         unsigned int len;
  47         unsigned int tx_count;
  48         unsigned int rx_count;
  49         const u8 *tx;
  50         u8 *rx;
  51
  52         void (*rx_word)(struct au1550_spi *hw);
  53         void (*tx_word)(struct au1550_spi *hw);
  54         int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
  55         irqreturn_t (*irq_callback)(struct au1550_spi *hw);
  56
  57         struct completion master_done;
  58
  59         unsigned int usedma;
  60         u32 dma_tx_id;
  61         u32 dma_rx_id;
  62         u32 dma_tx_ch;
  63         u32 dma_rx_ch;
  64
  65         u8 *dma_rx_tmpbuf;
  66         unsigned int dma_rx_tmpbuf_size;
  67         u32 dma_rx_tmpbuf_addr;
  68
  69         struct spi_master *master;
  70         struct device *dev;
  71         struct au1550_spi_info *pdata;
  72         struct resource *ioarea;
  73 };
  74
  75
  76 /* we use an 8-bit memory device for dma transfers to/from spi fifo */
  77 static dbdev_tab_t au1550_spi_mem_dbdev = {
  78         .dev_id                 = DBDMA_MEM_CHAN,
  79         .dev_flags              = DEV_FLAGS_ANYUSE|DEV_FLAGS_SYNC,
  80         .dev_tsize              = 0,
  81         .dev_devwidth           = 8,
  82         .dev_physaddr           = 0x00000000,
  83         .dev_intlevel           = 0,
  84         .dev_intpolarity        = 0
  85 };
  86
  87 static int ddma_memid;  /* id to above mem dma device */
  88
  89 static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw);
  90
  91
  92 /*
  93  *  compute BRG and DIV bits to setup spi clock based on main input clock rate
  94  *  that was specified in platform data structure
  95  *  according to au1550 datasheet:
  96  *    psc_tempclk = psc_mainclk / (2 << DIV)
  97  *    spiclk = psc_tempclk / (2 * (BRG + 1))
  98  *    BRG valid range is 4..63
  99  *    DIV valid range is 0..3
 100  */
 101 static u32 au1550_spi_baudcfg(struct au1550_spi *hw, unsigned int speed_hz)
 102 {
 103         u32 mainclk_hz = hw->pdata->mainclk_hz;
 104         u32 div, brg;
 105
 106         for (div = 0; div < 4; div++) {
 107                 brg = mainclk_hz / speed_hz / (4 << div);
 108                 /* now we have BRG+1 in brg, so count with that */
 109                 if (brg < (4 + 1)) {
 110                         brg = (4 + 1);  /* speed_hz too big */
 111                         break;          /* set lowest brg (div is == 0) */
 112                 }
 113                 if (brg <= (63 + 1))
 114                         break;          /* we have valid brg and div */
 115         }
 116         if (div == 4) {
 117                 div = 3;                /* speed_hz too small */
 118                 brg = (63 + 1);         /* set highest brg and div */
 119         }
 120         brg--;
 121         return PSC_SPICFG_SET_BAUD(brg) | PSC_SPICFG_SET_DIV(div);
 122 }
 123
 124 static inline void au1550_spi_mask_ack_all(struct au1550_spi *hw)
 125 {
 126         hw->regs->psc_spimsk =
 127                   PSC_SPIMSK_MM | PSC_SPIMSK_RR | PSC_SPIMSK_RO
 128                 | PSC_SPIMSK_RU | PSC_SPIMSK_TR | PSC_SPIMSK_TO
 129                 | PSC_SPIMSK_TU | PSC_SPIMSK_SD | PSC_SPIMSK_MD;
 130         wmb(); /* drain writebuffer */
 131
 132         hw->regs->psc_spievent =
 133                   PSC_SPIEVNT_MM | PSC_SPIEVNT_RR | PSC_SPIEVNT_RO
 134                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TR | PSC_SPIEVNT_TO
 135                 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD | PSC_SPIEVNT_MD;
 136         wmb(); /* drain writebuffer */
 137 }
 138
 139 static void au1550_spi_reset_fifos(struct au1550_spi *hw)
 140 {
 141         u32 pcr;
 142
 143         hw->regs->psc_spipcr = PSC_SPIPCR_RC | PSC_SPIPCR_TC;
 144         wmb(); /* drain writebuffer */
 145         do {
 146                 pcr = hw->regs->psc_spipcr;
 147                 wmb(); /* drain writebuffer */
 148         } while (pcr != 0);
 149 }
 150
 151 /*
 152  * dma transfers are used for the most common spi word size of 8-bits
 153  * we cannot easily change already set up dma channels' width, so if we wanted
 154  * dma support for more than 8-bit words (up to 24 bits), we would need to
 155  * setup dma channels from scratch on each spi transfer, based on bits_per_word
 156  * instead we have pre set up 8 bit dma channels supporting spi 4 to 8 bits
 157  * transfers, and 9 to 24 bits spi transfers will be done in pio irq based mode
 158  * callbacks to handle dma or pio are set up in au1550_spi_bits_handlers_set()
 159  */
 160 static void au1550_spi_chipsel(struct spi_device *spi, int value)
 161 {
 162         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 163         unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
 164         u32 cfg, stat;
 165
 166         switch (value) {
 167         case BITBANG_CS_INACTIVE:
 168                 if (hw->pdata->deactivate_cs)
 169                         hw->pdata->deactivate_cs(hw->pdata, spi->chip_select,
 170                                         cspol);
 171                 break;
 172
 173         case BITBANG_CS_ACTIVE:
 174                 au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
 175
 176                 cfg = hw->regs->psc_spicfg;
 177                 wmb(); /* drain writebuffer */
 178                 hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
 179                 wmb(); /* drain writebuffer */
 180
 181                 if (spi->mode & SPI_CPOL)
 182                         cfg |= PSC_SPICFG_BI;
 183                 else
 184                         cfg &= ~PSC_SPICFG_BI;
 185                 if (spi->mode & SPI_CPHA)
 186                         cfg &= ~PSC_SPICFG_CDE;
 187                 else
 188                         cfg |= PSC_SPICFG_CDE;
 189
 190                 if (spi->mode & SPI_LSB_FIRST)
 191                         cfg |= PSC_SPICFG_MLF;
 192                 else
 193                         cfg &= ~PSC_SPICFG_MLF;
 194
 195                 if (hw->usedma && spi->bits_per_word <= 8)
 196                         cfg &= ~PSC_SPICFG_DD_DISABLE;
 197                 else
 198                         cfg |= PSC_SPICFG_DD_DISABLE;
 199                 cfg = PSC_SPICFG_CLR_LEN(cfg);
 200                 cfg |= PSC_SPICFG_SET_LEN(spi->bits_per_word);
 201
 202                 cfg = PSC_SPICFG_CLR_BAUD(cfg);
 203                 cfg &= ~PSC_SPICFG_SET_DIV(3);
 204                 cfg |= au1550_spi_baudcfg(hw, spi->max_speed_hz);
 205
 206                 hw->regs->psc_spicfg = cfg | PSC_SPICFG_DE_ENABLE;
 207                 wmb(); /* drain writebuffer */
 208                 do {
 209                         stat = hw->regs->psc_spistat;
 210                         wmb(); /* drain writebuffer */
 211                 } while ((stat & PSC_SPISTAT_DR) == 0);
 212
 213                 if (hw->pdata->activate_cs)
 214                         hw->pdata->activate_cs(hw->pdata, spi->chip_select,
 215                                         cspol);
 216                 break;
 217         }
 218 }
 219
 220 static int au1550_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
 221 {
 222         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 223         unsigned int bpw, hz;
 224         u32 cfg, stat;
 225
 226         if (t) {
 227                 bpw = t->bits_per_word;
 228                 hz = t->speed_hz;
 229         } else {
 230                 bpw = spi->bits_per_word;
 231                 hz = spi->max_speed_hz;
 232         }
 233
 234         if (!hz)
 235                 return -EINVAL;
 236
 237         au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
 238
 239         cfg = hw->regs->psc_spicfg;
 240         wmb(); /* drain writebuffer */
 241         hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
 242         wmb(); /* drain writebuffer */
 243
 244         if (hw->usedma && bpw <= 8)
 245                 cfg &= ~PSC_SPICFG_DD_DISABLE;
 246         else
 247                 cfg |= PSC_SPICFG_DD_DISABLE;
 248         cfg = PSC_SPICFG_CLR_LEN(cfg);
 249         cfg |= PSC_SPICFG_SET_LEN(bpw);
 250
 251         cfg = PSC_SPICFG_CLR_BAUD(cfg);
 252         cfg &= ~PSC_SPICFG_SET_DIV(3);
 253         cfg |= au1550_spi_baudcfg(hw, hz);
 254
 255         hw->regs->psc_spicfg = cfg;
 256         wmb(); /* drain writebuffer */
 257
 258         if (cfg & PSC_SPICFG_DE_ENABLE) {
 259                 do {
 260                         stat = hw->regs->psc_spistat;
 261                         wmb(); /* drain writebuffer */
 262                 } while ((stat & PSC_SPISTAT_DR) == 0);
 263         }
 264
 265         au1550_spi_reset_fifos(hw);
 266         au1550_spi_mask_ack_all(hw);
 267         return 0;
 268 }
 269
 270 /*
 271  * for dma spi transfers, we have to setup rx channel, otherwise there is
 272  * no reliable way how to recognize that spi transfer is done
 273  * dma complete callbacks are called before real spi transfer is finished
 274  * and if only tx dma channel is set up (and rx fifo overflow event masked)
 275  * spi master done event irq is not generated unless rx fifo is empty (emptied)
 276  * so we need rx tmp buffer to use for rx dma if user does not provide one
 277  */
 278 static int au1550_spi_dma_rxtmp_alloc(struct au1550_spi *hw, unsigned int size)
 279 {
 280         hw->dma_rx_tmpbuf = kmalloc(size, GFP_KERNEL);
 281         if (!hw->dma_rx_tmpbuf)
 282                 return -ENOMEM;
 283         hw->dma_rx_tmpbuf_size = size;
 284         hw->dma_rx_tmpbuf_addr = dma_map_single(hw->dev, hw->dma_rx_tmpbuf,
 285                         size, DMA_FROM_DEVICE);
 286         if (dma_mapping_error(hw->dev, hw->dma_rx_tmpbuf_addr)) {
 287                 kfree(hw->dma_rx_tmpbuf);
 288                 hw->dma_rx_tmpbuf = 0;
 289                 hw->dma_rx_tmpbuf_size = 0;
 290                 return -EFAULT;
 291         }
 292         return 0;
 293 }
 294
 295 static void au1550_spi_dma_rxtmp_free(struct au1550_spi *hw)
 296 {
 297         dma_unmap_single(hw->dev, hw->dma_rx_tmpbuf_addr,
 298                         hw->dma_rx_tmpbuf_size, DMA_FROM_DEVICE);
 299         kfree(hw->dma_rx_tmpbuf);
 300         hw->dma_rx_tmpbuf = 0;
 301         hw->dma_rx_tmpbuf_size = 0;
 302 }
 303
 304 static int au1550_spi_dma_txrxb(struct spi_device *spi, struct spi_transfer *t)
 305 {
 306         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 307         dma_addr_t dma_tx_addr;
 308         dma_addr_t dma_rx_addr;
 309         u32 res;
 310
 311         hw->len = t->len;
 312         hw->tx_count = 0;
 313         hw->rx_count = 0;
 314
 315         hw->tx = t->tx_buf;
 316         hw->rx = t->rx_buf;
 317         dma_tx_addr = t->tx_dma;
 318         dma_rx_addr = t->rx_dma;
 319
 320         /*
 321          * check if buffers are already dma mapped, map them otherwise:
 322          * - first map the TX buffer, so cache data gets written to memory
 323          * - then map the RX buffer, so that cache entries (with
 324          *   soon-to-be-stale data) get removed
 325          * use rx buffer in place of tx if tx buffer was not provided
 326          * use temp rx buffer (preallocated or realloc to fit) for rx dma
 327          */
 328         if (t->tx_buf) {
 329                 if (t->tx_dma == 0) {   /* if DMA_ADDR_INVALID, map it */
 330                         dma_tx_addr = dma_map_single(hw->dev,
 331                                         (void *)t->tx_buf,
 332                                         t->len, DMA_TO_DEVICE);
 333                         if (dma_mapping_error(hw->dev, dma_tx_addr))
 334                                 dev_err(hw->dev, "tx dma map error\n");
 335                 }
 336         }
 337
 338         if (t->rx_buf) {
 339                 if (t->rx_dma == 0) {   /* if DMA_ADDR_INVALID, map it */
 340                         dma_rx_addr = dma_map_single(hw->dev,
 341                                         (void *)t->rx_buf,
 342                                         t->len, DMA_FROM_DEVICE);
 343                         if (dma_mapping_error(hw->dev, dma_rx_addr))
 344                                 dev_err(hw->dev, "rx dma map error\n");
 345                 }
 346         } else {
 347                 if (t->len > hw->dma_rx_tmpbuf_size) {
 348                         int ret;
 349
 350                         au1550_spi_dma_rxtmp_free(hw);
 351                         ret = au1550_spi_dma_rxtmp_alloc(hw, max(t->len,
 352                                         AU1550_SPI_DMA_RXTMP_MINSIZE));
 353                         if (ret < 0)
 354                                 return ret;
 355                 }
 356                 hw->rx = hw->dma_rx_tmpbuf;
 357                 dma_rx_addr = hw->dma_rx_tmpbuf_addr;
 358                 dma_sync_single_for_device(hw->dev, dma_rx_addr,
 359                         t->len, DMA_FROM_DEVICE);
 360         }
 361
 362         if (!t->tx_buf) {
 363                 dma_sync_single_for_device(hw->dev, dma_rx_addr,
 364                                 t->len, DMA_BIDIRECTIONAL);
 365                 hw->tx = hw->rx;
 366         }
 367
 368         /* put buffers on the ring */
 369         res = au1xxx_dbdma_put_dest(hw->dma_rx_ch, virt_to_phys(hw->rx),
 370                                     t->len, DDMA_FLAGS_IE);
 371         if (!res)
 372                 dev_err(hw->dev, "rx dma put dest error\n");
 373
 374         res = au1xxx_dbdma_put_source(hw->dma_tx_ch, virt_to_phys(hw->tx),
 375                                       t->len, DDMA_FLAGS_IE);
 376         if (!res)
 377                 dev_err(hw->dev, "tx dma put source error\n");
 378
 379         au1xxx_dbdma_start(hw->dma_rx_ch);
 380         au1xxx_dbdma_start(hw->dma_tx_ch);
 381
 382         /* by default enable nearly all events interrupt */
 383         hw->regs->psc_spimsk = PSC_SPIMSK_SD;
 384         wmb(); /* drain writebuffer */
 385
 386         /* start the transfer */
 387         hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 388         wmb(); /* drain writebuffer */
 389
 390         wait_for_completion(&hw->master_done);
 391
 392         au1xxx_dbdma_stop(hw->dma_tx_ch);
 393         au1xxx_dbdma_stop(hw->dma_rx_ch);
 394
 395         if (!t->rx_buf) {
 396                 /* using the temporal preallocated and premapped buffer */
 397                 dma_sync_single_for_cpu(hw->dev, dma_rx_addr, t->len,
 398                         DMA_FROM_DEVICE);
 399         }
 400         /* unmap buffers if mapped above */
 401         if (t->rx_buf && t->rx_dma == 0)
 402                 dma_unmap_single(hw->dev, dma_rx_addr, t->len,
 403                         DMA_FROM_DEVICE);
 404         if (t->tx_buf && t->tx_dma == 0)
 405                 dma_unmap_single(hw->dev, dma_tx_addr, t->len,
 406                         DMA_TO_DEVICE);
 407
 408         return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
 409 }
 410
 411 static irqreturn_t au1550_spi_dma_irq_callback(struct au1550_spi *hw)
 412 {
 413         u32 stat, evnt;
 414
 415         stat = hw->regs->psc_spistat;
 416         evnt = hw->regs->psc_spievent;
 417         wmb(); /* drain writebuffer */
 418         if ((stat & PSC_SPISTAT_DI) == 0) {
 419                 dev_err(hw->dev, "Unexpected IRQ!\n");
 420                 return IRQ_NONE;
 421         }
 422
 423         if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
 424                                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
 425                                 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD))
 426                         != 0) {
 427                 /*
 428                  * due to an spi error we consider transfer as done,
 429                  * so mask all events until before next transfer start
 430                  * and stop the possibly running dma immediately
 431                  */
 432                 au1550_spi_mask_ack_all(hw);
 433                 au1xxx_dbdma_stop(hw->dma_rx_ch);
 434                 au1xxx_dbdma_stop(hw->dma_tx_ch);
 435
 436                 /* get number of transferred bytes */
 437                 hw->rx_count = hw->len - au1xxx_get_dma_residue(hw->dma_rx_ch);
 438                 hw->tx_count = hw->len - au1xxx_get_dma_residue(hw->dma_tx_ch);
 439
 440                 au1xxx_dbdma_reset(hw->dma_rx_ch);
 441                 au1xxx_dbdma_reset(hw->dma_tx_ch);
 442                 au1550_spi_reset_fifos(hw);
 443
 444                 if (evnt == PSC_SPIEVNT_RO)
 445                         dev_err(hw->dev,
 446                                 "dma transfer: receive FIFO overflow!\n");
 447                 else
 448                         dev_err(hw->dev,
 449                                 "dma transfer: unexpected SPI error (event=0x%x stat=0x%x)!\n",
 450                                 evnt, stat);
 451
 452                 complete(&hw->master_done);
 453                 return IRQ_HANDLED;
 454         }
 455
 456         if ((evnt & PSC_SPIEVNT_MD) != 0) {
 457                 /* transfer completed successfully */
 458                 au1550_spi_mask_ack_all(hw);
 459                 hw->rx_count = hw->len;
 460                 hw->tx_count = hw->len;
 461                 complete(&hw->master_done);
 462         }
 463         return IRQ_HANDLED;
 464 }
 465
 466
 467 /* routines to handle different word sizes in pio mode */
 468 #define AU1550_SPI_RX_WORD(size, mask)                                  \
 469 static void au1550_spi_rx_word_##size(struct au1550_spi *hw)            \
 470 {                                                                       \
 471         u32 fifoword = hw->regs->psc_spitxrx & (u32)(mask);             \
 472         wmb(); /* drain writebuffer */                                  \
 473         if (hw->rx) {                                                   \
 474                 *(u##size *)hw->rx = (u##size)fifoword;                 \
 475                 hw->rx += (size) / 8;                                   \
 476         }                                                               \
 477         hw->rx_count += (size) / 8;                                     \
 478 }
 479
 480 #define AU1550_SPI_TX_WORD(size, mask)                                  \
 481 static void au1550_spi_tx_word_##size(struct au1550_spi *hw)            \
 482 {                                                                       \
 483         u32 fifoword = 0;                                               \
 484         if (hw->tx) {                                                   \
 485                 fifoword = *(u##size *)hw->tx & (u32)(mask);            \
 486                 hw->tx += (size) / 8;                                   \
 487         }                                                               \
 488         hw->tx_count += (size) / 8;                                     \
 489         if (hw->tx_count >= hw->len)                                    \
 490                 fifoword |= PSC_SPITXRX_LC;                             \
 491         hw->regs->psc_spitxrx = fifoword;                               \
 492         wmb(); /* drain writebuffer */                                  \
 493 }
 494
 495 AU1550_SPI_RX_WORD(8, 0xff)
 496 AU1550_SPI_RX_WORD(16, 0xffff)
 497 AU1550_SPI_RX_WORD(32, 0xffffff)
 498 AU1550_SPI_TX_WORD(8, 0xff)
 499 AU1550_SPI_TX_WORD(16, 0xffff)
 500 AU1550_SPI_TX_WORD(32, 0xffffff)
 501
 502 static int au1550_spi_pio_txrxb(struct spi_device *spi, struct spi_transfer *t)
 503 {
 504         u32 stat, mask;
 505         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 506
 507         hw->tx = t->tx_buf;
 508         hw->rx = t->rx_buf;
 509         hw->len = t->len;
 510         hw->tx_count = 0;
 511         hw->rx_count = 0;
 512
 513         /* by default enable nearly all events after filling tx fifo */
 514         mask = PSC_SPIMSK_SD;
 515
 516         /* fill the transmit FIFO */
 517         while (hw->tx_count < hw->len) {
 518
 519                 hw->tx_word(hw);
 520
 521                 if (hw->tx_count >= hw->len) {
 522                         /* mask tx fifo request interrupt as we are done */
 523                         mask |= PSC_SPIMSK_TR;
 524                 }
 525
 526                 stat = hw->regs->psc_spistat;
 527                 wmb(); /* drain writebuffer */
 528                 if (stat & PSC_SPISTAT_TF)
 529                         break;
 530         }
 531
 532         /* enable event interrupts */
 533         hw->regs->psc_spimsk = mask;
 534         wmb(); /* drain writebuffer */
 535
 536         /* start the transfer */
 537         hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 538         wmb(); /* drain writebuffer */
 539
 540         wait_for_completion(&hw->master_done);
 541
 542         return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
 543 }
 544
 545 static irqreturn_t au1550_spi_pio_irq_callback(struct au1550_spi *hw)
 546 {
 547         int busy;
 548         u32 stat, evnt;
 549
 550         stat = hw->regs->psc_spistat;
 551         evnt = hw->regs->psc_spievent;
 552         wmb(); /* drain writebuffer */
 553         if ((stat & PSC_SPISTAT_DI) == 0) {
 554                 dev_err(hw->dev, "Unexpected IRQ!\n");
 555                 return IRQ_NONE;
 556         }
 557
 558         if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
 559                                 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
 560                                 | PSC_SPIEVNT_SD))
 561                         != 0) {
 562                 /*
 563                  * due to an error we consider transfer as done,
 564                  * so mask all events until before next transfer start
 565                  */
 566                 au1550_spi_mask_ack_all(hw);
 567                 au1550_spi_reset_fifos(hw);
 568                 dev_err(hw->dev,
 569                         "pio transfer: unexpected SPI error (event=0x%x stat=0x%x)!\n",
 570                         evnt, stat);
 571                 complete(&hw->master_done);
 572                 return IRQ_HANDLED;
 573         }
 574
 575         /*
 576          * while there is something to read from rx fifo
 577          * or there is a space to write to tx fifo:
 578          */
 579         do {
 580                 busy = 0;
 581                 stat = hw->regs->psc_spistat;
 582                 wmb(); /* drain writebuffer */
 583
 584                 /*
 585                  * Take care to not let the Rx FIFO overflow.
 586                  *
 587                  * We only write a byte if we have read one at least. Initially,
 588                  * the write fifo is full, so we should read from the read fifo
 589                  * first.
 590                  * In case we miss a word from the read fifo, we should get a
 591                  * RO event and should back out.
 592                  */
 593                 if (!(stat & PSC_SPISTAT_RE) && hw->rx_count < hw->len) {
 594                         hw->rx_word(hw);
 595                         busy = 1;
 596
 597                         if (!(stat & PSC_SPISTAT_TF) && hw->tx_count < hw->len)
 598                                 hw->tx_word(hw);
 599                 }
 600         } while (busy);
 601
 602         hw->regs->psc_spievent = PSC_SPIEVNT_RR | PSC_SPIEVNT_TR;
 603         wmb(); /* drain writebuffer */
 604
 605         /*
 606          * Restart the SPI transmission in case of a transmit underflow.
 607          * This seems to work despite the notes in the Au1550 data book
 608          * of Figure 8-4 with flowchart for SPI master operation:
 609          *
 610          * """Note 1: An XFR Error Interrupt occurs, unless masked,
 611          * for any of the following events: Tx FIFO Underflow,
 612          * Rx FIFO Overflow, or Multiple-master Error
 613          *    Note 2: In case of a Tx Underflow Error, all zeroes are
 614          * transmitted."""
 615          *
 616          * By simply restarting the spi transfer on Tx Underflow Error,
 617          * we assume that spi transfer was paused instead of zeroes
 618          * transmittion mentioned in the Note 2 of Au1550 data book.
 619          */
 620         if (evnt & PSC_SPIEVNT_TU) {
 621                 hw->regs->psc_spievent = PSC_SPIEVNT_TU | PSC_SPIEVNT_MD;
 622                 wmb(); /* drain writebuffer */
 623                 hw->regs->psc_spipcr = PSC_SPIPCR_MS;
 624                 wmb(); /* drain writebuffer */
 625         }
 626
 627         if (hw->rx_count >= hw->len) {
 628                 /* transfer completed successfully */
 629                 au1550_spi_mask_ack_all(hw);
 630                 complete(&hw->master_done);
 631         }
 632         return IRQ_HANDLED;
 633 }
 634
 635 static int au1550_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
 636 {
 637         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 638
 639         return hw->txrx_bufs(spi, t);
 640 }
 641
 642 static irqreturn_t au1550_spi_irq(int irq, void *dev)
 643 {
 644         struct au1550_spi *hw = dev;
 645
 646         return hw->irq_callback(hw);
 647 }
 648
 649 static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw)
 650 {
 651         if (bpw <= 8) {
 652                 if (hw->usedma) {
 653                         hw->txrx_bufs = &au1550_spi_dma_txrxb;
 654                         hw->irq_callback = &au1550_spi_dma_irq_callback;
 655                 } else {
 656                         hw->rx_word = &au1550_spi_rx_word_8;
 657                         hw->tx_word = &au1550_spi_tx_word_8;
 658                         hw->txrx_bufs = &au1550_spi_pio_txrxb;
 659                         hw->irq_callback = &au1550_spi_pio_irq_callback;
 660                 }
 661         } else if (bpw <= 16) {
 662                 hw->rx_word = &au1550_spi_rx_word_16;
 663                 hw->tx_word = &au1550_spi_tx_word_16;
 664                 hw->txrx_bufs = &au1550_spi_pio_txrxb;
 665                 hw->irq_callback = &au1550_spi_pio_irq_callback;
 666         } else {
 667                 hw->rx_word = &au1550_spi_rx_word_32;
 668                 hw->tx_word = &au1550_spi_tx_word_32;
 669                 hw->txrx_bufs = &au1550_spi_pio_txrxb;
 670                 hw->irq_callback = &au1550_spi_pio_irq_callback;
 671         }
 672 }
 673
 674 static void au1550_spi_setup_psc_as_spi(struct au1550_spi *hw)
 675 {
 676         u32 stat, cfg;
 677
 678         /* set up the PSC for SPI mode */
 679         hw->regs->psc_ctrl = PSC_CTRL_DISABLE;
 680         wmb(); /* drain writebuffer */
 681         hw->regs->psc_sel = PSC_SEL_PS_SPIMODE;
 682         wmb(); /* drain writebuffer */
 683
 684         hw->regs->psc_spicfg = 0;
 685         wmb(); /* drain writebuffer */
 686
 687         hw->regs->psc_ctrl = PSC_CTRL_ENABLE;
 688         wmb(); /* drain writebuffer */
 689
 690         do {
 691                 stat = hw->regs->psc_spistat;
 692                 wmb(); /* drain writebuffer */
 693         } while ((stat & PSC_SPISTAT_SR) == 0);
 694
 695
 696         cfg = hw->usedma ? 0 : PSC_SPICFG_DD_DISABLE;
 697         cfg |= PSC_SPICFG_SET_LEN(8);
 698         cfg |= PSC_SPICFG_RT_FIFO8 | PSC_SPICFG_TT_FIFO8;
 699         /* use minimal allowed brg and div values as initial setting: */
 700         cfg |= PSC_SPICFG_SET_BAUD(4) | PSC_SPICFG_SET_DIV(0);
 701
 702 #ifdef AU1550_SPI_DEBUG_LOOPBACK
 703         cfg |= PSC_SPICFG_LB;
 704 #endif
 705
 706         hw->regs->psc_spicfg = cfg;
 707         wmb(); /* drain writebuffer */
 708
 709         au1550_spi_mask_ack_all(hw);
 710
 711         hw->regs->psc_spicfg |= PSC_SPICFG_DE_ENABLE;
 712         wmb(); /* drain writebuffer */
 713
 714         do {
 715                 stat = hw->regs->psc_spistat;
 716                 wmb(); /* drain writebuffer */
 717         } while ((stat & PSC_SPISTAT_DR) == 0);
 718
 719         au1550_spi_reset_fifos(hw);
 720 }
 721
 722
 723 static int au1550_spi_probe(struct platform_device *pdev)
 724 {
 725         struct au1550_spi *hw;
 726         struct spi_master *master;
 727         struct resource *r;
 728         int err = 0;
 729
 730         master = spi_alloc_master(&pdev->dev, sizeof(struct au1550_spi));
 731         if (master == NULL) {
 732                 dev_err(&pdev->dev, "No memory for spi_master\n");
 733                 err = -ENOMEM;
 734                 goto err_nomem;
 735         }
 736
 737         /* the spi->mode bits understood by this driver: */
 738         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
 739         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 24);
 740
 741         hw = spi_master_get_devdata(master);
 742
 743         hw->master = master;
 744         hw->pdata = dev_get_platdata(&pdev->dev);
 745         hw->dev = &pdev->dev;
 746
 747         if (hw->pdata == NULL) {
 748                 dev_err(&pdev->dev, "No platform data supplied\n");
 749                 err = -ENOENT;
 750                 goto err_no_pdata;
 751         }
 752
 753         r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 754         if (!r) {
 755                 dev_err(&pdev->dev, "no IRQ\n");
 756                 err = -ENODEV;
 757                 goto err_no_iores;
 758         }
 759         hw->irq = r->start;
 760
 761         hw->usedma = 0;
 762         r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 763         if (r) {
 764                 hw->dma_tx_id = r->start;
 765                 r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
 766                 if (r) {
 767                         hw->dma_rx_id = r->start;
 768                         if (usedma && ddma_memid) {
 769                                 if (pdev->dev.dma_mask == NULL)
 770                                         dev_warn(&pdev->dev, "no dma mask\n");
 771                                 else
 772                                         hw->usedma = 1;
 773                         }
 774                 }
 775         }
 776
 777         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 778         if (!r) {
 779                 dev_err(&pdev->dev, "no mmio resource\n");
 780                 err = -ENODEV;
 781                 goto err_no_iores;
 782         }
 783
 784         hw->ioarea = request_mem_region(r->start, sizeof(psc_spi_t),
 785                                         pdev->name);
 786         if (!hw->ioarea) {
 787                 dev_err(&pdev->dev, "Cannot reserve iomem region\n");
 788                 err = -ENXIO;
 789                 goto err_no_iores;
 790         }
 791
 792         hw->regs = (psc_spi_t __iomem *)ioremap(r->start, sizeof(psc_spi_t));
 793         if (!hw->regs) {
 794                 dev_err(&pdev->dev, "cannot ioremap\n");
 795                 err = -ENXIO;
 796                 goto err_ioremap;
 797         }
 798
 799         platform_set_drvdata(pdev, hw);
 800
 801         init_completion(&hw->master_done);
 802
 803         hw->bitbang.master = hw->master;
 804         hw->bitbang.setup_transfer = au1550_spi_setupxfer;
 805         hw->bitbang.chipselect = au1550_spi_chipsel;
 806         hw->bitbang.txrx_bufs = au1550_spi_txrx_bufs;
 807
 808         if (hw->usedma) {
 809                 hw->dma_tx_ch = au1xxx_dbdma_chan_alloc(ddma_memid,
 810                         hw->dma_tx_id, NULL, (void *)hw);
 811                 if (hw->dma_tx_ch == 0) {
 812                         dev_err(&pdev->dev,
 813                                 "Cannot allocate tx dma channel\n");
 814                         err = -ENXIO;
 815                         goto err_no_txdma;
 816                 }
 817                 au1xxx_dbdma_set_devwidth(hw->dma_tx_ch, 8);
 818                 if (au1xxx_dbdma_ring_alloc(hw->dma_tx_ch,
 819                         AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
 820                         dev_err(&pdev->dev,
 821                                 "Cannot allocate tx dma descriptors\n");
 822                         err = -ENXIO;
 823                         goto err_no_txdma_descr;
 824                 }
 825
 826
 827                 hw->dma_rx_ch = au1xxx_dbdma_chan_alloc(hw->dma_rx_id,
 828                         ddma_memid, NULL, (void *)hw);
 829                 if (hw->dma_rx_ch == 0) {
 830                         dev_err(&pdev->dev,
 831                                 "Cannot allocate rx dma channel\n");
 832                         err = -ENXIO;
 833                         goto err_no_rxdma;
 834                 }
 835                 au1xxx_dbdma_set_devwidth(hw->dma_rx_ch, 8);
 836                 if (au1xxx_dbdma_ring_alloc(hw->dma_rx_ch,
 837                         AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
 838                         dev_err(&pdev->dev,
 839                                 "Cannot allocate rx dma descriptors\n");
 840                         err = -ENXIO;
 841                         goto err_no_rxdma_descr;
 842                 }
 843
 844                 err = au1550_spi_dma_rxtmp_alloc(hw,
 845                         AU1550_SPI_DMA_RXTMP_MINSIZE);
 846                 if (err < 0) {
 847                         dev_err(&pdev->dev,
 848                                 "Cannot allocate initial rx dma tmp buffer\n");
 849                         goto err_dma_rxtmp_alloc;
 850                 }
 851         }
 852
 853         au1550_spi_bits_handlers_set(hw, 8);
 854
 855         err = request_irq(hw->irq, au1550_spi_irq, 0, pdev->name, hw);
 856         if (err) {
 857                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
 858                 goto err_no_irq;
 859         }
 860
 861         master->bus_num = pdev->id;
 862         master->num_chipselect = hw->pdata->num_chipselect;
 863
 864         /*
 865          *  precompute valid range for spi freq - from au1550 datasheet:
 866          *    psc_tempclk = psc_mainclk / (2 << DIV)
 867          *    spiclk = psc_tempclk / (2 * (BRG + 1))
 868          *    BRG valid range is 4..63
 869          *    DIV valid range is 0..3
 870          *  round the min and max frequencies to values that would still
 871          *  produce valid brg and div
 872          */
 873         {
 874                 int min_div = (2 << 0) * (2 * (4 + 1));
 875                 int max_div = (2 << 3) * (2 * (63 + 1));
 876
 877                 master->max_speed_hz = hw->pdata->mainclk_hz / min_div;
 878                 master->min_speed_hz =
 879                                 hw->pdata->mainclk_hz / (max_div + 1) + 1;
 880         }
 881
 882         au1550_spi_setup_psc_as_spi(hw);
 883
 884         err = spi_bitbang_start(&hw->bitbang);
 885         if (err) {
 886                 dev_err(&pdev->dev, "Failed to register SPI master\n");
 887                 goto err_register;
 888         }
 889
 890         dev_info(&pdev->dev,
 891                 "spi master registered: bus_num=%d num_chipselect=%d\n",
 892                 master->bus_num, master->num_chipselect);
 893
 894         return 0;
 895
 896 err_register:
 897         free_irq(hw->irq, hw);
 898
 899 err_no_irq:
 900         au1550_spi_dma_rxtmp_free(hw);
 901
 902 err_dma_rxtmp_alloc:
 903 err_no_rxdma_descr:
 904         if (hw->usedma)
 905                 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
 906
 907 err_no_rxdma:
 908 err_no_txdma_descr:
 909         if (hw->usedma)
 910                 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
 911
 912 err_no_txdma:
 913         iounmap((void __iomem *)hw->regs);
 914
 915 err_ioremap:
 916         release_mem_region(r->start, sizeof(psc_spi_t));
 917
 918 err_no_iores:
 919 err_no_pdata:
 920         spi_master_put(hw->master);
 921
 922 err_nomem:
 923         return err;
 924 }
 925
 926 static int au1550_spi_remove(struct platform_device *pdev)
 927 {
 928         struct au1550_spi *hw = platform_get_drvdata(pdev);
 929
 930         dev_info(&pdev->dev, "spi master remove: bus_num=%d\n",
 931                 hw->master->bus_num);
 932
 933         spi_bitbang_stop(&hw->bitbang);
 934         free_irq(hw->irq, hw);
 935         iounmap((void __iomem *)hw->regs);
 936         release_mem_region(hw->ioarea->start, sizeof(psc_spi_t));
 937
 938         if (hw->usedma) {
 939                 au1550_spi_dma_rxtmp_free(hw);
 940                 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
 941                 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
 942         }
 943
 944         spi_master_put(hw->master);
 945         return 0;
 946 }
 947
 948 /* work with hotplug and coldplug */
 949 MODULE_ALIAS("platform:au1550-spi");
 950
 951 static struct platform_driver au1550_spi_drv = {
 952         .probe = au1550_spi_probe,
 953         .remove = au1550_spi_remove,
 954         .driver = {
 955                 .name = "au1550-spi",
 956         },
 957 };
 958
 959 static int __init au1550_spi_init(void)
 960 {
 961         /*
 962          * create memory device with 8 bits dev_devwidth
 963          * needed for proper byte ordering to spi fifo
 964          */
 965         switch (alchemy_get_cputype()) {
 966         case ALCHEMY_CPU_AU1550:
 967         case ALCHEMY_CPU_AU1200:
 968         case ALCHEMY_CPU_AU1300:
 969                 break;
 970         default:
 971                 return -ENODEV;
 972         }
 973
 974         if (usedma) {
 975                 ddma_memid = au1xxx_ddma_add_device(&au1550_spi_mem_dbdev);
 976                 if (!ddma_memid)
 977                         printk(KERN_ERR "au1550-spi: cannot add memory dbdma device\n");
 978         }
 979         return platform_driver_register(&au1550_spi_drv);
 980 }
 981 module_init(au1550_spi_init);
 982
 983 static void __exit au1550_spi_exit(void)
 984 {
 985         if (usedma && ddma_memid)
 986                 au1xxx_ddma_del_device(ddma_memid);
 987         platform_driver_unregister(&au1550_spi_drv);
 988 }
 989 module_exit(au1550_spi_exit);
 990
 991 MODULE_DESCRIPTION("Au1550 PSC SPI Driver");
 992 MODULE_AUTHOR("Jan Nikitenko <jan.nikitenko@gmail.com>");
 993 MODULE_LICENSE("GPL");