drivers/spi/spi-bcm63xx-hsspi.c

   1 /*
   2  * Broadcom BCM63XX High Speed SPI Controller driver
   3  *
   4  * Copyright 2000-2010 Broadcom Corporation
   5  * Copyright 2012-2013 Jonas Gorski <jogo@openwrt.org>
   6  *
   7  * Licensed under the GNU/GPL. See COPYING for details.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/io.h>
  13 #include <linux/clk.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/delay.h>
  17 #include <linux/dma-mapping.h>
  18 #include <linux/err.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/spi/spi.h>
  21 #include <linux/mutex.h>
  22 #include <linux/of.h>
  23
  24 #define HSSPI_GLOBAL_CTRL_REG                   0x0
  25 #define GLOBAL_CTRL_CS_POLARITY_SHIFT           0
  26 #define GLOBAL_CTRL_CS_POLARITY_MASK            0x000000ff
  27 #define GLOBAL_CTRL_PLL_CLK_CTRL_SHIFT          8
  28 #define GLOBAL_CTRL_PLL_CLK_CTRL_MASK           0x0000ff00
  29 #define GLOBAL_CTRL_CLK_GATE_SSOFF              BIT(16)
  30 #define GLOBAL_CTRL_CLK_POLARITY                BIT(17)
  31 #define GLOBAL_CTRL_MOSI_IDLE                   BIT(18)
  32
  33 #define HSSPI_GLOBAL_EXT_TRIGGER_REG            0x4
  34
  35 #define HSSPI_INT_STATUS_REG                    0x8
  36 #define HSSPI_INT_STATUS_MASKED_REG             0xc
  37 #define HSSPI_INT_MASK_REG                      0x10
  38
  39 #define HSSPI_PINGx_CMD_DONE(i)                 BIT((i * 8) + 0)
  40 #define HSSPI_PINGx_RX_OVER(i)                  BIT((i * 8) + 1)
  41 #define HSSPI_PINGx_TX_UNDER(i)                 BIT((i * 8) + 2)
  42 #define HSSPI_PINGx_POLL_TIMEOUT(i)             BIT((i * 8) + 3)
  43 #define HSSPI_PINGx_CTRL_INVAL(i)               BIT((i * 8) + 4)
  44
  45 #define HSSPI_INT_CLEAR_ALL                     0xff001f1f
  46
  47 #define HSSPI_PINGPONG_COMMAND_REG(x)           (0x80 + (x) * 0x40)
  48 #define PINGPONG_CMD_COMMAND_MASK               0xf
  49 #define PINGPONG_COMMAND_NOOP                   0
  50 #define PINGPONG_COMMAND_START_NOW              1
  51 #define PINGPONG_COMMAND_START_TRIGGER          2
  52 #define PINGPONG_COMMAND_HALT                   3
  53 #define PINGPONG_COMMAND_FLUSH                  4
  54 #define PINGPONG_CMD_PROFILE_SHIFT              8
  55 #define PINGPONG_CMD_SS_SHIFT                   12
  56
  57 #define HSSPI_PINGPONG_STATUS_REG(x)            (0x84 + (x) * 0x40)
  58
  59 #define HSSPI_PROFILE_CLK_CTRL_REG(x)           (0x100 + (x) * 0x20)
  60 #define CLK_CTRL_FREQ_CTRL_MASK                 0x0000ffff
  61 #define CLK_CTRL_SPI_CLK_2X_SEL                 BIT(14)
  62 #define CLK_CTRL_ACCUM_RST_ON_LOOP              BIT(15)
  63
  64 #define HSSPI_PROFILE_SIGNAL_CTRL_REG(x)        (0x104 + (x) * 0x20)
  65 #define SIGNAL_CTRL_LATCH_RISING                BIT(12)
  66 #define SIGNAL_CTRL_LAUNCH_RISING               BIT(13)
  67 #define SIGNAL_CTRL_ASYNC_INPUT_PATH            BIT(16)
  68
  69 #define HSSPI_PROFILE_MODE_CTRL_REG(x)          (0x108 + (x) * 0x20)
  70 #define MODE_CTRL_MULTIDATA_RD_STRT_SHIFT       8
  71 #define MODE_CTRL_MULTIDATA_WR_STRT_SHIFT       12
  72 #define MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT       16
  73 #define MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT       18
  74 #define MODE_CTRL_MODE_3WIRE                    BIT(20)
  75 #define MODE_CTRL_PREPENDBYTE_CNT_SHIFT         24
  76
  77 #define HSSPI_FIFO_REG(x)                       (0x200 + (x) * 0x200)
  78
  79
  80 #define HSSPI_OP_MULTIBIT                       BIT(11)
  81 #define HSSPI_OP_CODE_SHIFT                     13
  82 #define HSSPI_OP_SLEEP                          (0 << HSSPI_OP_CODE_SHIFT)
  83 #define HSSPI_OP_READ_WRITE                     (1 << HSSPI_OP_CODE_SHIFT)
  84 #define HSSPI_OP_WRITE                          (2 << HSSPI_OP_CODE_SHIFT)
  85 #define HSSPI_OP_READ                           (3 << HSSPI_OP_CODE_SHIFT)
  86 #define HSSPI_OP_SETIRQ                         (4 << HSSPI_OP_CODE_SHIFT)
  87
  88 #define HSSPI_BUFFER_LEN                        512
  89 #define HSSPI_OPCODE_LEN                        2
  90
  91 #define HSSPI_MAX_PREPEND_LEN                   15
  92
  93 #define HSSPI_MAX_SYNC_CLOCK                    30000000
  94
  95 #define HSSPI_SPI_MAX_CS                        8
  96 #define HSSPI_BUS_NUM                           1 /* 0 is legacy SPI */
  97
  98 struct bcm63xx_hsspi {
  99         struct completion done;
 100         struct mutex bus_mutex;
 101
 102         struct platform_device *pdev;
 103         struct clk *clk;
 104         void __iomem *regs;
 105         u8 __iomem *fifo;
 106
 107         u32 speed_hz;
 108         u8 cs_polarity;
 109 };
 110
 111 static void bcm63xx_hsspi_set_cs(struct bcm63xx_hsspi *bs, unsigned cs,
 112                                  bool active)
 113 {
 114         u32 reg;
 115
 116         mutex_lock(&bs->bus_mutex);
 117         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 118
 119         reg &= ~BIT(cs);
 120         if (active == !(bs->cs_polarity & BIT(cs)))
 121                 reg |= BIT(cs);
 122
 123         __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 124         mutex_unlock(&bs->bus_mutex);
 125 }
 126
 127 static void bcm63xx_hsspi_set_clk(struct bcm63xx_hsspi *bs,
 128                                   struct spi_device *spi, int hz)
 129 {
 130         unsigned profile = spi->chip_select;
 131         u32 reg;
 132
 133         reg = DIV_ROUND_UP(2048, DIV_ROUND_UP(bs->speed_hz, hz));
 134         __raw_writel(CLK_CTRL_ACCUM_RST_ON_LOOP | reg,
 135                      bs->regs + HSSPI_PROFILE_CLK_CTRL_REG(profile));
 136
 137         reg = __raw_readl(bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));
 138         if (hz > HSSPI_MAX_SYNC_CLOCK)
 139                 reg |= SIGNAL_CTRL_ASYNC_INPUT_PATH;
 140         else
 141                 reg &= ~SIGNAL_CTRL_ASYNC_INPUT_PATH;
 142         __raw_writel(reg, bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));
 143
 144         mutex_lock(&bs->bus_mutex);
 145         /* setup clock polarity */
 146         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 147         reg &= ~GLOBAL_CTRL_CLK_POLARITY;
 148         if (spi->mode & SPI_CPOL)
 149                 reg |= GLOBAL_CTRL_CLK_POLARITY;
 150         __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 151         mutex_unlock(&bs->bus_mutex);
 152 }
 153
 154 static int bcm63xx_hsspi_do_txrx(struct spi_device *spi, struct spi_transfer *t)
 155 {
 156         struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
 157         unsigned chip_select = spi->chip_select;
 158         u16 opcode = 0;
 159         int pending = t->len;
 160         int step_size = HSSPI_BUFFER_LEN;
 161         const u8 *tx = t->tx_buf;
 162         u8 *rx = t->rx_buf;
 163
 164         bcm63xx_hsspi_set_clk(bs, spi, t->speed_hz);
 165         bcm63xx_hsspi_set_cs(bs, spi->chip_select, true);
 166
 167         if (tx && rx)
 168                 opcode = HSSPI_OP_READ_WRITE;
 169         else if (tx)
 170                 opcode = HSSPI_OP_WRITE;
 171         else if (rx)
 172                 opcode = HSSPI_OP_READ;
 173
 174         if (opcode != HSSPI_OP_READ)
 175                 step_size -= HSSPI_OPCODE_LEN;
 176
 177         if ((opcode == HSSPI_OP_READ && t->rx_nbits == SPI_NBITS_DUAL) ||
 178             (opcode == HSSPI_OP_WRITE && t->tx_nbits == SPI_NBITS_DUAL))
 179                 opcode |= HSSPI_OP_MULTIBIT;
 180
 181         __raw_writel(1 << MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT |
 182                      1 << MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT | 0xff,
 183                      bs->regs + HSSPI_PROFILE_MODE_CTRL_REG(chip_select));
 184
 185         while (pending > 0) {
 186                 int curr_step = min_t(int, step_size, pending);
 187
 188                 reinit_completion(&bs->done);
 189                 if (tx) {
 190                         memcpy_toio(bs->fifo + HSSPI_OPCODE_LEN, tx, curr_step);
 191                         tx += curr_step;
 192                 }
 193
 194                 __raw_writew(opcode | curr_step, bs->fifo);
 195
 196                 /* enable interrupt */
 197                 __raw_writel(HSSPI_PINGx_CMD_DONE(0),
 198                              bs->regs + HSSPI_INT_MASK_REG);
 199
 200                 /* start the transfer */
 201                 __raw_writel(!chip_select << PINGPONG_CMD_SS_SHIFT |
 202                              chip_select << PINGPONG_CMD_PROFILE_SHIFT |
 203                              PINGPONG_COMMAND_START_NOW,
 204                              bs->regs + HSSPI_PINGPONG_COMMAND_REG(0));
 205
 206                 if (wait_for_completion_timeout(&bs->done, HZ) == 0) {
 207                         dev_err(&bs->pdev->dev, "transfer timed out!\n");
 208                         return -ETIMEDOUT;
 209                 }
 210
 211                 if (rx) {
 212                         memcpy_fromio(rx, bs->fifo, curr_step);
 213                         rx += curr_step;
 214                 }
 215
 216                 pending -= curr_step;
 217         }
 218
 219         return 0;
 220 }
 221
 222 static int bcm63xx_hsspi_setup(struct spi_device *spi)
 223 {
 224         struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
 225         u32 reg;
 226
 227         reg = __raw_readl(bs->regs +
 228                           HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));
 229         reg &= ~(SIGNAL_CTRL_LAUNCH_RISING | SIGNAL_CTRL_LATCH_RISING);
 230         if (spi->mode & SPI_CPHA)
 231                 reg |= SIGNAL_CTRL_LAUNCH_RISING;
 232         else
 233                 reg |= SIGNAL_CTRL_LATCH_RISING;
 234         __raw_writel(reg, bs->regs +
 235                      HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));
 236
 237         mutex_lock(&bs->bus_mutex);
 238         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 239
 240         /* only change actual polarities if there is no transfer */
 241         if ((reg & GLOBAL_CTRL_CS_POLARITY_MASK) == bs->cs_polarity) {
 242                 if (spi->mode & SPI_CS_HIGH)
 243                         reg |= BIT(spi->chip_select);
 244                 else
 245                         reg &= ~BIT(spi->chip_select);
 246                 __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 247         }
 248
 249         if (spi->mode & SPI_CS_HIGH)
 250                 bs->cs_polarity |= BIT(spi->chip_select);
 251         else
 252                 bs->cs_polarity &= ~BIT(spi->chip_select);
 253
 254         mutex_unlock(&bs->bus_mutex);
 255
 256         return 0;
 257 }
 258
 259 static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
 260                                       struct spi_message *msg)
 261 {
 262         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 263         struct spi_transfer *t;
 264         struct spi_device *spi = msg->spi;
 265         int status = -EINVAL;
 266         int dummy_cs;
 267         u32 reg;
 268
 269         /* This controller does not support keeping CS active during idle.
 270          * To work around this, we use the following ugly hack:
 271          *
 272          * a. Invert the target chip select's polarity so it will be active.
 273          * b. Select a "dummy" chip select to use as the hardware target.
 274          * c. Invert the dummy chip select's polarity so it will be inactive
 275          *    during the actual transfers.
 276          * d. Tell the hardware to send to the dummy chip select. Thanks to
 277          *    the multiplexed nature of SPI the actual target will receive
 278          *    the transfer and we see its response.
 279          *
 280          * e. At the end restore the polarities again to their default values.
 281          */
 282
 283         dummy_cs = !spi->chip_select;
 284         bcm63xx_hsspi_set_cs(bs, dummy_cs, true);
 285
 286         list_for_each_entry(t, &msg->transfers, transfer_list) {
 287                 status = bcm63xx_hsspi_do_txrx(spi, t);
 288                 if (status)
 289                         break;
 290
 291                 msg->actual_length += t->len;
 292
 293                 if (t->delay_usecs)
 294                         udelay(t->delay_usecs);
 295
 296                 if (t->cs_change)
 297                         bcm63xx_hsspi_set_cs(bs, spi->chip_select, false);
 298         }
 299
 300         mutex_lock(&bs->bus_mutex);
 301         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 302         reg &= ~GLOBAL_CTRL_CS_POLARITY_MASK;
 303         reg |= bs->cs_polarity;
 304         __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 305         mutex_unlock(&bs->bus_mutex);
 306
 307         msg->status = status;
 308         spi_finalize_current_message(master);
 309
 310         return 0;
 311 }
 312
 313 static irqreturn_t bcm63xx_hsspi_interrupt(int irq, void *dev_id)
 314 {
 315         struct bcm63xx_hsspi *bs = (struct bcm63xx_hsspi *)dev_id;
 316
 317         if (__raw_readl(bs->regs + HSSPI_INT_STATUS_MASKED_REG) == 0)
 318                 return IRQ_NONE;
 319
 320         __raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);
 321         __raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 322
 323         complete(&bs->done);
 324
 325         return IRQ_HANDLED;
 326 }
 327
 328 static int bcm63xx_hsspi_probe(struct platform_device *pdev)
 329 {
 330         struct spi_master *master;
 331         struct bcm63xx_hsspi *bs;
 332         struct resource *res_mem;
 333         void __iomem *regs;
 334         struct device *dev = &pdev->dev;
 335         struct clk *clk;
 336         int irq, ret;
 337         u32 reg, rate, num_cs = HSSPI_SPI_MAX_CS;
 338
 339         irq = platform_get_irq(pdev, 0);
 340         if (irq < 0) {
 341                 dev_err(dev, "no irq\n");
 342                 return -ENXIO;
 343         }
 344
 345         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 346         regs = devm_ioremap_resource(dev, res_mem);
 347         if (IS_ERR(regs))
 348                 return PTR_ERR(regs);
 349
 350         clk = devm_clk_get(dev, "hsspi");
 351
 352         if (IS_ERR(clk))
 353                 return PTR_ERR(clk);
 354
 355         rate = clk_get_rate(clk);
 356         if (!rate) {
 357                 struct clk *pll_clk = devm_clk_get(dev, "pll");
 358
 359                 if (IS_ERR(pll_clk))
 360                         return PTR_ERR(pll_clk);
 361
 362                 rate = clk_get_rate(pll_clk);
 363                 if (!rate)
 364                         return -EINVAL;
 365         }
 366
 367         ret = clk_prepare_enable(clk);
 368         if (ret)
 369                 return ret;
 370
 371         master = spi_alloc_master(&pdev->dev, sizeof(*bs));
 372         if (!master) {
 373                 ret = -ENOMEM;
 374                 goto out_disable_clk;
 375         }
 376
 377         bs = spi_master_get_devdata(master);
 378         bs->pdev = pdev;
 379         bs->clk = clk;
 380         bs->regs = regs;
 381         bs->speed_hz = rate;
 382         bs->fifo = (u8 __iomem *)(bs->regs + HSSPI_FIFO_REG(0));
 383
 384         mutex_init(&bs->bus_mutex);
 385         init_completion(&bs->done);
 386
 387         master->dev.of_node = dev->of_node;
 388         if (!dev->of_node)
 389                 master->bus_num = HSSPI_BUS_NUM;
 390
 391         of_property_read_u32(dev->of_node, "num-cs", &num_cs);
 392         if (num_cs > 8) {
 393                 dev_warn(dev, "unsupported number of cs (%i), reducing to 8\n",
 394                          num_cs);
 395                 num_cs = HSSPI_SPI_MAX_CS;
 396         }
 397         master->num_chipselect = num_cs;
 398         master->setup = bcm63xx_hsspi_setup;
 399         master->transfer_one_message = bcm63xx_hsspi_transfer_one;
 400         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH |
 401                             SPI_RX_DUAL | SPI_TX_DUAL;
 402         master->bits_per_word_mask = SPI_BPW_MASK(8);
 403         master->auto_runtime_pm = true;
 404
 405         platform_set_drvdata(pdev, master);
 406
 407         /* Initialize the hardware */
 408         __raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 409
 410         /* clean up any pending interrupts */
 411         __raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);
 412
 413         /* read out default CS polarities */
 414         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 415         bs->cs_polarity = reg & GLOBAL_CTRL_CS_POLARITY_MASK;
 416         __raw_writel(reg | GLOBAL_CTRL_CLK_GATE_SSOFF,
 417                      bs->regs + HSSPI_GLOBAL_CTRL_REG);
 418
 419         ret = devm_request_irq(dev, irq, bcm63xx_hsspi_interrupt, IRQF_SHARED,
 420                                pdev->name, bs);
 421
 422         if (ret)
 423                 goto out_put_master;
 424
 425         /* register and we are done */
 426         ret = devm_spi_register_master(dev, master);
 427         if (ret)
 428                 goto out_put_master;
 429
 430         return 0;
 431
 432 out_put_master:
 433         spi_master_put(master);
 434 out_disable_clk:
 435         clk_disable_unprepare(clk);
 436         return ret;
 437 }
 438
 439
 440 static int bcm63xx_hsspi_remove(struct platform_device *pdev)
 441 {
 442         struct spi_master *master = platform_get_drvdata(pdev);
 443         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 444
 445         /* reset the hardware and block queue progress */
 446         __raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 447         clk_disable_unprepare(bs->clk);
 448
 449         return 0;
 450 }
 451
 452 #ifdef CONFIG_PM_SLEEP
 453 static int bcm63xx_hsspi_suspend(struct device *dev)
 454 {
 455         struct spi_master *master = dev_get_drvdata(dev);
 456         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 457
 458         spi_master_suspend(master);
 459         clk_disable_unprepare(bs->clk);
 460
 461         return 0;
 462 }
 463
 464 static int bcm63xx_hsspi_resume(struct device *dev)
 465 {
 466         struct spi_master *master = dev_get_drvdata(dev);
 467         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 468         int ret;
 469
 470         ret = clk_prepare_enable(bs->clk);
 471         if (ret)
 472                 return ret;
 473
 474         spi_master_resume(master);
 475
 476         return 0;
 477 }
 478 #endif
 479
 480 static SIMPLE_DEV_PM_OPS(bcm63xx_hsspi_pm_ops, bcm63xx_hsspi_suspend,
 481                          bcm63xx_hsspi_resume);
 482
 483 static const struct of_device_id bcm63xx_hsspi_of_match[] = {
 484         { .compatible = "brcm,bcm6328-hsspi", },
 485         { },
 486 };
 487 MODULE_DEVICE_TABLE(of, bcm63xx_hsspi_of_match);
 488
 489 static struct platform_driver bcm63xx_hsspi_driver = {
 490         .driver = {
 491                 .name   = "bcm63xx-hsspi",
 492                 .pm     = &bcm63xx_hsspi_pm_ops,
 493                 .of_match_table = bcm63xx_hsspi_of_match,
 494         },
 495         .probe          = bcm63xx_hsspi_probe,
 496         .remove         = bcm63xx_hsspi_remove,
 497 };
 498
 499 module_platform_driver(bcm63xx_hsspi_driver);
 500
 501 MODULE_ALIAS("platform:bcm63xx_hsspi");
 502 MODULE_DESCRIPTION("Broadcom BCM63xx High Speed SPI Controller driver");
 503 MODULE_AUTHOR("Jonas Gorski <jogo@openwrt.org>");
 504 MODULE_LICENSE("GPL");