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         struct clk *pll_clk;
 105         void __iomem *regs;
 106         u8 __iomem *fifo;
 107
 108         u32 speed_hz;
 109         u8 cs_polarity;
 110 };
 111
 112 static void bcm63xx_hsspi_set_cs(struct bcm63xx_hsspi *bs, unsigned int cs,
 113                                  bool active)
 114 {
 115         u32 reg;
 116
 117         mutex_lock(&bs->bus_mutex);
 118         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 119
 120         reg &= ~BIT(cs);
 121         if (active == !(bs->cs_polarity & BIT(cs)))
 122                 reg |= BIT(cs);
 123
 124         __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 125         mutex_unlock(&bs->bus_mutex);
 126 }
 127
 128 static void bcm63xx_hsspi_set_clk(struct bcm63xx_hsspi *bs,
 129                                   struct spi_device *spi, int hz)
 130 {
 131         unsigned int profile = spi->chip_select;
 132         u32 reg;
 133
 134         reg = DIV_ROUND_UP(2048, DIV_ROUND_UP(bs->speed_hz, hz));
 135         __raw_writel(CLK_CTRL_ACCUM_RST_ON_LOOP | reg,
 136                      bs->regs + HSSPI_PROFILE_CLK_CTRL_REG(profile));
 137
 138         reg = __raw_readl(bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));
 139         if (hz > HSSPI_MAX_SYNC_CLOCK)
 140                 reg |= SIGNAL_CTRL_ASYNC_INPUT_PATH;
 141         else
 142                 reg &= ~SIGNAL_CTRL_ASYNC_INPUT_PATH;
 143         __raw_writel(reg, bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));
 144
 145         mutex_lock(&bs->bus_mutex);
 146         /* setup clock polarity */
 147         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 148         reg &= ~GLOBAL_CTRL_CLK_POLARITY;
 149         if (spi->mode & SPI_CPOL)
 150                 reg |= GLOBAL_CTRL_CLK_POLARITY;
 151         __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 152         mutex_unlock(&bs->bus_mutex);
 153 }
 154
 155 static int bcm63xx_hsspi_do_txrx(struct spi_device *spi, struct spi_transfer *t)
 156 {
 157         struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
 158         unsigned int chip_select = spi->chip_select;
 159         u16 opcode = 0;
 160         int pending = t->len;
 161         int step_size = HSSPI_BUFFER_LEN;
 162         const u8 *tx = t->tx_buf;
 163         u8 *rx = t->rx_buf;
 164
 165         bcm63xx_hsspi_set_clk(bs, spi, t->speed_hz);
 166         bcm63xx_hsspi_set_cs(bs, spi->chip_select, true);
 167
 168         if (tx && rx)
 169                 opcode = HSSPI_OP_READ_WRITE;
 170         else if (tx)
 171                 opcode = HSSPI_OP_WRITE;
 172         else if (rx)
 173                 opcode = HSSPI_OP_READ;
 174
 175         if (opcode != HSSPI_OP_READ)
 176                 step_size -= HSSPI_OPCODE_LEN;
 177
 178         if ((opcode == HSSPI_OP_READ && t->rx_nbits == SPI_NBITS_DUAL) ||
 179             (opcode == HSSPI_OP_WRITE && t->tx_nbits == SPI_NBITS_DUAL))
 180                 opcode |= HSSPI_OP_MULTIBIT;
 181
 182         __raw_writel(1 << MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT |
 183                      1 << MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT | 0xff,
 184                      bs->regs + HSSPI_PROFILE_MODE_CTRL_REG(chip_select));
 185
 186         while (pending > 0) {
 187                 int curr_step = min_t(int, step_size, pending);
 188
 189                 reinit_completion(&bs->done);
 190                 if (tx) {
 191                         memcpy_toio(bs->fifo + HSSPI_OPCODE_LEN, tx, curr_step);
 192                         tx += curr_step;
 193                 }
 194
 195                 __raw_writew(opcode | curr_step, bs->fifo);
 196
 197                 /* enable interrupt */
 198                 __raw_writel(HSSPI_PINGx_CMD_DONE(0),
 199                              bs->regs + HSSPI_INT_MASK_REG);
 200
 201                 /* start the transfer */
 202                 __raw_writel(!chip_select << PINGPONG_CMD_SS_SHIFT |
 203                              chip_select << PINGPONG_CMD_PROFILE_SHIFT |
 204                              PINGPONG_COMMAND_START_NOW,
 205                              bs->regs + HSSPI_PINGPONG_COMMAND_REG(0));
 206
 207                 if (wait_for_completion_timeout(&bs->done, HZ) == 0) {
 208                         dev_err(&bs->pdev->dev, "transfer timed out!\n");
 209                         return -ETIMEDOUT;
 210                 }
 211
 212                 if (rx) {
 213                         memcpy_fromio(rx, bs->fifo, curr_step);
 214                         rx += curr_step;
 215                 }
 216
 217                 pending -= curr_step;
 218         }
 219
 220         return 0;
 221 }
 222
 223 static int bcm63xx_hsspi_setup(struct spi_device *spi)
 224 {
 225         struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
 226         u32 reg;
 227
 228         reg = __raw_readl(bs->regs +
 229                           HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));
 230         reg &= ~(SIGNAL_CTRL_LAUNCH_RISING | SIGNAL_CTRL_LATCH_RISING);
 231         if (spi->mode & SPI_CPHA)
 232                 reg |= SIGNAL_CTRL_LAUNCH_RISING;
 233         else
 234                 reg |= SIGNAL_CTRL_LATCH_RISING;
 235         __raw_writel(reg, bs->regs +
 236                      HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));
 237
 238         mutex_lock(&bs->bus_mutex);
 239         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 240
 241         /* only change actual polarities if there is no transfer */
 242         if ((reg & GLOBAL_CTRL_CS_POLARITY_MASK) == bs->cs_polarity) {
 243                 if (spi->mode & SPI_CS_HIGH)
 244                         reg |= BIT(spi->chip_select);
 245                 else
 246                         reg &= ~BIT(spi->chip_select);
 247                 __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 248         }
 249
 250         if (spi->mode & SPI_CS_HIGH)
 251                 bs->cs_polarity |= BIT(spi->chip_select);
 252         else
 253                 bs->cs_polarity &= ~BIT(spi->chip_select);
 254
 255         mutex_unlock(&bs->bus_mutex);
 256
 257         return 0;
 258 }
 259
 260 static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
 261                                       struct spi_message *msg)
 262 {
 263         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 264         struct spi_transfer *t;
 265         struct spi_device *spi = msg->spi;
 266         int status = -EINVAL;
 267         int dummy_cs;
 268         u32 reg;
 269
 270         /* This controller does not support keeping CS active during idle.
 271          * To work around this, we use the following ugly hack:
 272          *
 273          * a. Invert the target chip select's polarity so it will be active.
 274          * b. Select a "dummy" chip select to use as the hardware target.
 275          * c. Invert the dummy chip select's polarity so it will be inactive
 276          *    during the actual transfers.
 277          * d. Tell the hardware to send to the dummy chip select. Thanks to
 278          *    the multiplexed nature of SPI the actual target will receive
 279          *    the transfer and we see its response.
 280          *
 281          * e. At the end restore the polarities again to their default values.
 282          */
 283
 284         dummy_cs = !spi->chip_select;
 285         bcm63xx_hsspi_set_cs(bs, dummy_cs, true);
 286
 287         list_for_each_entry(t, &msg->transfers, transfer_list) {
 288                 status = bcm63xx_hsspi_do_txrx(spi, t);
 289                 if (status)
 290                         break;
 291
 292                 msg->actual_length += t->len;
 293
 294                 if (t->delay_usecs)
 295                         udelay(t->delay_usecs);
 296
 297                 if (t->cs_change)
 298                         bcm63xx_hsspi_set_cs(bs, spi->chip_select, false);
 299         }
 300
 301         mutex_lock(&bs->bus_mutex);
 302         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 303         reg &= ~GLOBAL_CTRL_CS_POLARITY_MASK;
 304         reg |= bs->cs_polarity;
 305         __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 306         mutex_unlock(&bs->bus_mutex);
 307
 308         msg->status = status;
 309         spi_finalize_current_message(master);
 310
 311         return 0;
 312 }
 313
 314 static irqreturn_t bcm63xx_hsspi_interrupt(int irq, void *dev_id)
 315 {
 316         struct bcm63xx_hsspi *bs = (struct bcm63xx_hsspi *)dev_id;
 317
 318         if (__raw_readl(bs->regs + HSSPI_INT_STATUS_MASKED_REG) == 0)
 319                 return IRQ_NONE;
 320
 321         __raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);
 322         __raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 323
 324         complete(&bs->done);
 325
 326         return IRQ_HANDLED;
 327 }
 328
 329 static int bcm63xx_hsspi_probe(struct platform_device *pdev)
 330 {
 331         struct spi_master *master;
 332         struct bcm63xx_hsspi *bs;
 333         void __iomem *regs;
 334         struct device *dev = &pdev->dev;
 335         struct clk *clk, *pll_clk = NULL;
 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                 return irq;
 342
 343         regs = devm_platform_ioremap_resource(pdev, 0);
 344         if (IS_ERR(regs))
 345                 return PTR_ERR(regs);
 346
 347         clk = devm_clk_get(dev, "hsspi");
 348
 349         if (IS_ERR(clk))
 350                 return PTR_ERR(clk);
 351
 352         ret = clk_prepare_enable(clk);
 353         if (ret)
 354                 return ret;
 355
 356         rate = clk_get_rate(clk);
 357         if (!rate) {
 358                 pll_clk = devm_clk_get(dev, "pll");
 359
 360                 if (IS_ERR(pll_clk)) {
 361                         ret = PTR_ERR(pll_clk);
 362                         goto out_disable_clk;
 363                 }
 364
 365                 ret = clk_prepare_enable(pll_clk);
 366                 if (ret)
 367                         goto out_disable_clk;
 368
 369                 rate = clk_get_rate(pll_clk);
 370                 clk_disable_unprepare(pll_clk);
 371                 if (!rate) {
 372                         ret = -EINVAL;
 373                         goto out_disable_pll_clk;
 374                 }
 375         }
 376
 377         master = spi_alloc_master(&pdev->dev, sizeof(*bs));
 378         if (!master) {
 379                 ret = -ENOMEM;
 380                 goto out_disable_pll_clk;
 381         }
 382
 383         bs = spi_master_get_devdata(master);
 384         bs->pdev = pdev;
 385         bs->clk = clk;
 386         bs->pll_clk = pll_clk;
 387         bs->regs = regs;
 388         bs->speed_hz = rate;
 389         bs->fifo = (u8 __iomem *)(bs->regs + HSSPI_FIFO_REG(0));
 390
 391         mutex_init(&bs->bus_mutex);
 392         init_completion(&bs->done);
 393
 394         master->dev.of_node = dev->of_node;
 395         if (!dev->of_node)
 396                 master->bus_num = HSSPI_BUS_NUM;
 397
 398         of_property_read_u32(dev->of_node, "num-cs", &num_cs);
 399         if (num_cs > 8) {
 400                 dev_warn(dev, "unsupported number of cs (%i), reducing to 8\n",
 401                          num_cs);
 402                 num_cs = HSSPI_SPI_MAX_CS;
 403         }
 404         master->num_chipselect = num_cs;
 405         master->setup = bcm63xx_hsspi_setup;
 406         master->transfer_one_message = bcm63xx_hsspi_transfer_one;
 407         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH |
 408                             SPI_RX_DUAL | SPI_TX_DUAL;
 409         master->bits_per_word_mask = SPI_BPW_MASK(8);
 410         master->auto_runtime_pm = true;
 411
 412         platform_set_drvdata(pdev, master);
 413
 414         /* Initialize the hardware */
 415         __raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 416
 417         /* clean up any pending interrupts */
 418         __raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);
 419
 420         /* read out default CS polarities */
 421         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 422         bs->cs_polarity = reg & GLOBAL_CTRL_CS_POLARITY_MASK;
 423         __raw_writel(reg | GLOBAL_CTRL_CLK_GATE_SSOFF,
 424                      bs->regs + HSSPI_GLOBAL_CTRL_REG);
 425
 426         ret = devm_request_irq(dev, irq, bcm63xx_hsspi_interrupt, IRQF_SHARED,
 427                                pdev->name, bs);
 428
 429         if (ret)
 430                 goto out_put_master;
 431
 432         /* register and we are done */
 433         ret = devm_spi_register_master(dev, master);
 434         if (ret)
 435                 goto out_put_master;
 436
 437         return 0;
 438
 439 out_put_master:
 440         spi_master_put(master);
 441 out_disable_pll_clk:
 442         clk_disable_unprepare(pll_clk);
 443 out_disable_clk:
 444         clk_disable_unprepare(clk);
 445         return ret;
 446 }
 447
 448
 449 static int bcm63xx_hsspi_remove(struct platform_device *pdev)
 450 {
 451         struct spi_master *master = platform_get_drvdata(pdev);
 452         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 453
 454         /* reset the hardware and block queue progress */
 455         __raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 456         clk_disable_unprepare(bs->pll_clk);
 457         clk_disable_unprepare(bs->clk);
 458
 459         return 0;
 460 }
 461
 462 #ifdef CONFIG_PM_SLEEP
 463 static int bcm63xx_hsspi_suspend(struct device *dev)
 464 {
 465         struct spi_master *master = dev_get_drvdata(dev);
 466         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 467
 468         spi_master_suspend(master);
 469         clk_disable_unprepare(bs->pll_clk);
 470         clk_disable_unprepare(bs->clk);
 471
 472         return 0;
 473 }
 474
 475 static int bcm63xx_hsspi_resume(struct device *dev)
 476 {
 477         struct spi_master *master = dev_get_drvdata(dev);
 478         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 479         int ret;
 480
 481         ret = clk_prepare_enable(bs->clk);
 482         if (ret)
 483                 return ret;
 484
 485         if (bs->pll_clk) {
 486                 ret = clk_prepare_enable(bs->pll_clk);
 487                 if (ret)
 488                         return ret;
 489         }
 490
 491         spi_master_resume(master);
 492
 493         return 0;
 494 }
 495 #endif
 496
 497 static SIMPLE_DEV_PM_OPS(bcm63xx_hsspi_pm_ops, bcm63xx_hsspi_suspend,
 498                          bcm63xx_hsspi_resume);
 499
 500 static const struct of_device_id bcm63xx_hsspi_of_match[] = {
 501         { .compatible = "brcm,bcm6328-hsspi", },
 502         { },
 503 };
 504 MODULE_DEVICE_TABLE(of, bcm63xx_hsspi_of_match);
 505
 506 static struct platform_driver bcm63xx_hsspi_driver = {
 507         .driver = {
 508                 .name   = "bcm63xx-hsspi",
 509                 .pm     = &bcm63xx_hsspi_pm_ops,
 510                 .of_match_table = bcm63xx_hsspi_of_match,
 511         },
 512         .probe          = bcm63xx_hsspi_probe,
 513         .remove         = bcm63xx_hsspi_remove,
 514 };
 515
 516 module_platform_driver(bcm63xx_hsspi_driver);
 517
 518 MODULE_ALIAS("platform:bcm63xx_hsspi");
 519 MODULE_DESCRIPTION("Broadcom BCM63xx High Speed SPI Controller driver");
 520 MODULE_AUTHOR("Jonas Gorski <jogo@openwrt.org>");
 521 MODULE_LICENSE("GPL");