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/workqueue.h>
  22 #include <linux/mutex.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_CODE_SHIFT                     13
  81 #define HSSPI_OP_SLEEP                          (0 << HSSPI_OP_CODE_SHIFT)
  82 #define HSSPI_OP_READ_WRITE                     (1 << HSSPI_OP_CODE_SHIFT)
  83 #define HSSPI_OP_WRITE                          (2 << HSSPI_OP_CODE_SHIFT)
  84 #define HSSPI_OP_READ                           (3 << HSSPI_OP_CODE_SHIFT)
  85 #define HSSPI_OP_SETIRQ                         (4 << HSSPI_OP_CODE_SHIFT)
  86
  87 #define HSSPI_BUFFER_LEN                        512
  88 #define HSSPI_OPCODE_LEN                        2
  89
  90 #define HSSPI_MAX_PREPEND_LEN                   15
  91
  92 #define HSSPI_MAX_SYNC_CLOCK                    30000000
  93
  94 #define HSSPI_BUS_NUM                           1 /* 0 is legacy SPI */
  95
  96 struct bcm63xx_hsspi {
  97         struct completion done;
  98         struct mutex bus_mutex;
  99
 100         struct platform_device *pdev;
 101         struct clk *clk;
 102         void __iomem *regs;
 103         u8 __iomem *fifo;
 104
 105         u32 speed_hz;
 106         u8 cs_polarity;
 107 };
 108
 109 static void bcm63xx_hsspi_set_cs(struct bcm63xx_hsspi *bs, unsigned cs,
 110                                  bool active)
 111 {
 112         u32 reg;
 113
 114         mutex_lock(&bs->bus_mutex);
 115         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 116
 117         reg &= ~BIT(cs);
 118         if (active == !(bs->cs_polarity & BIT(cs)))
 119                 reg |= BIT(cs);
 120
 121         __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 122         mutex_unlock(&bs->bus_mutex);
 123 }
 124
 125 static void bcm63xx_hsspi_set_clk(struct bcm63xx_hsspi *bs,
 126                                   struct spi_device *spi, int hz)
 127 {
 128         unsigned profile = spi->chip_select;
 129         u32 reg;
 130
 131         reg = DIV_ROUND_UP(2048, DIV_ROUND_UP(bs->speed_hz, hz));
 132         __raw_writel(CLK_CTRL_ACCUM_RST_ON_LOOP | reg,
 133                      bs->regs + HSSPI_PROFILE_CLK_CTRL_REG(profile));
 134
 135         reg = __raw_readl(bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));
 136         if (hz > HSSPI_MAX_SYNC_CLOCK)
 137                 reg |= SIGNAL_CTRL_ASYNC_INPUT_PATH;
 138         else
 139                 reg &= ~SIGNAL_CTRL_ASYNC_INPUT_PATH;
 140         __raw_writel(reg, bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));
 141
 142         mutex_lock(&bs->bus_mutex);
 143         /* setup clock polarity */
 144         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 145         reg &= ~GLOBAL_CTRL_CLK_POLARITY;
 146         if (spi->mode & SPI_CPOL)
 147                 reg |= GLOBAL_CTRL_CLK_POLARITY;
 148         __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 149         mutex_unlock(&bs->bus_mutex);
 150 }
 151
 152 static int bcm63xx_hsspi_do_txrx(struct spi_device *spi, struct spi_transfer *t)
 153 {
 154         struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
 155         unsigned chip_select = spi->chip_select;
 156         u16 opcode = 0;
 157         int pending = t->len;
 158         int step_size = HSSPI_BUFFER_LEN;
 159         const u8 *tx = t->tx_buf;
 160         u8 *rx = t->rx_buf;
 161
 162         bcm63xx_hsspi_set_clk(bs, spi, t->speed_hz);
 163         bcm63xx_hsspi_set_cs(bs, spi->chip_select, true);
 164
 165         if (tx && rx)
 166                 opcode = HSSPI_OP_READ_WRITE;
 167         else if (tx)
 168                 opcode = HSSPI_OP_WRITE;
 169         else if (rx)
 170                 opcode = HSSPI_OP_READ;
 171
 172         if (opcode != HSSPI_OP_READ)
 173                 step_size -= HSSPI_OPCODE_LEN;
 174
 175         __raw_writel(0 << MODE_CTRL_PREPENDBYTE_CNT_SHIFT |
 176                      2 << MODE_CTRL_MULTIDATA_WR_STRT_SHIFT |
 177                      2 << MODE_CTRL_MULTIDATA_RD_STRT_SHIFT | 0xff,
 178                      bs->regs + HSSPI_PROFILE_MODE_CTRL_REG(chip_select));
 179
 180         while (pending > 0) {
 181                 int curr_step = min_t(int, step_size, pending);
 182
 183                 init_completion(&bs->done);
 184                 if (tx) {
 185                         memcpy_toio(bs->fifo + HSSPI_OPCODE_LEN, tx, curr_step);
 186                         tx += curr_step;
 187                 }
 188
 189                 __raw_writew(opcode | curr_step, bs->fifo);
 190
 191                 /* enable interrupt */
 192                 __raw_writel(HSSPI_PINGx_CMD_DONE(0),
 193                              bs->regs + HSSPI_INT_MASK_REG);
 194
 195                 /* start the transfer */
 196                 __raw_writel(!chip_select << PINGPONG_CMD_SS_SHIFT |
 197                              chip_select << PINGPONG_CMD_PROFILE_SHIFT |
 198                              PINGPONG_COMMAND_START_NOW,
 199                              bs->regs + HSSPI_PINGPONG_COMMAND_REG(0));
 200
 201                 if (wait_for_completion_timeout(&bs->done, HZ) == 0) {
 202                         dev_err(&bs->pdev->dev, "transfer timed out!\n");
 203                         return -ETIMEDOUT;
 204                 }
 205
 206                 if (rx) {
 207                         memcpy_fromio(rx, bs->fifo, curr_step);
 208                         rx += curr_step;
 209                 }
 210
 211                 pending -= curr_step;
 212         }
 213
 214         return 0;
 215 }
 216
 217 static int bcm63xx_hsspi_setup(struct spi_device *spi)
 218 {
 219         struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
 220         u32 reg;
 221
 222         reg = __raw_readl(bs->regs +
 223                           HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));
 224         reg &= ~(SIGNAL_CTRL_LAUNCH_RISING | SIGNAL_CTRL_LATCH_RISING);
 225         if (spi->mode & SPI_CPHA)
 226                 reg |= SIGNAL_CTRL_LAUNCH_RISING;
 227         else
 228                 reg |= SIGNAL_CTRL_LATCH_RISING;
 229         __raw_writel(reg, bs->regs +
 230                      HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));
 231
 232         mutex_lock(&bs->bus_mutex);
 233         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 234
 235         /* only change actual polarities if there is no transfer */
 236         if ((reg & GLOBAL_CTRL_CS_POLARITY_MASK) == bs->cs_polarity) {
 237                 if (spi->mode & SPI_CS_HIGH)
 238                         reg |= BIT(spi->chip_select);
 239                 else
 240                         reg &= ~BIT(spi->chip_select);
 241                 __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 242         }
 243
 244         if (spi->mode & SPI_CS_HIGH)
 245                 bs->cs_polarity |= BIT(spi->chip_select);
 246         else
 247                 bs->cs_polarity &= ~BIT(spi->chip_select);
 248
 249         mutex_unlock(&bs->bus_mutex);
 250
 251         return 0;
 252 }
 253
 254 static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
 255                                       struct spi_message *msg)
 256 {
 257         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 258         struct spi_transfer *t;
 259         struct spi_device *spi = msg->spi;
 260         int status = -EINVAL;
 261         int dummy_cs;
 262         u32 reg;
 263
 264         /* This controller does not support keeping CS active during idle.
 265          * To work around this, we use the following ugly hack:
 266          *
 267          * a. Invert the target chip select's polarity so it will be active.
 268          * b. Select a "dummy" chip select to use as the hardware target.
 269          * c. Invert the dummy chip select's polarity so it will be inactive
 270          *    during the actual transfers.
 271          * d. Tell the hardware to send to the dummy chip select. Thanks to
 272          *    the multiplexed nature of SPI the actual target will receive
 273          *    the transfer and we see its response.
 274          *
 275          * e. At the end restore the polarities again to their default values.
 276          */
 277
 278         dummy_cs = !spi->chip_select;
 279         bcm63xx_hsspi_set_cs(bs, dummy_cs, true);
 280
 281         list_for_each_entry(t, &msg->transfers, transfer_list) {
 282                 status = bcm63xx_hsspi_do_txrx(spi, t);
 283                 if (status)
 284                         break;
 285
 286                 msg->actual_length += t->len;
 287
 288                 if (t->delay_usecs)
 289                         udelay(t->delay_usecs);
 290
 291                 if (t->cs_change)
 292                         bcm63xx_hsspi_set_cs(bs, spi->chip_select, false);
 293         }
 294
 295         mutex_lock(&bs->bus_mutex);
 296         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 297         reg &= ~GLOBAL_CTRL_CS_POLARITY_MASK;
 298         reg |= bs->cs_polarity;
 299         __raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 300         mutex_unlock(&bs->bus_mutex);
 301
 302         msg->status = status;
 303         spi_finalize_current_message(master);
 304
 305         return 0;
 306 }
 307
 308 static irqreturn_t bcm63xx_hsspi_interrupt(int irq, void *dev_id)
 309 {
 310         struct bcm63xx_hsspi *bs = (struct bcm63xx_hsspi *)dev_id;
 311
 312         if (__raw_readl(bs->regs + HSSPI_INT_STATUS_MASKED_REG) == 0)
 313                 return IRQ_NONE;
 314
 315         __raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);
 316         __raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 317
 318         complete(&bs->done);
 319
 320         return IRQ_HANDLED;
 321 }
 322
 323 static int bcm63xx_hsspi_probe(struct platform_device *pdev)
 324 {
 325         struct spi_master *master;
 326         struct bcm63xx_hsspi *bs;
 327         struct resource *res_mem;
 328         void __iomem *regs;
 329         struct device *dev = &pdev->dev;
 330         struct clk *clk;
 331         int irq, ret;
 332         u32 reg, rate;
 333
 334         irq = platform_get_irq(pdev, 0);
 335         if (irq < 0) {
 336                 dev_err(dev, "no irq\n");
 337                 return -ENXIO;
 338         }
 339
 340         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 341         regs = devm_ioremap_resource(dev, res_mem);
 342         if (IS_ERR(regs))
 343                 return PTR_ERR(regs);
 344
 345         clk = devm_clk_get(dev, "hsspi");
 346
 347         if (IS_ERR(clk))
 348                 return PTR_ERR(clk);
 349
 350         rate = clk_get_rate(clk);
 351         if (!rate)
 352                 return -EINVAL;
 353
 354         ret = clk_prepare_enable(clk);
 355         if (ret)
 356                 return ret;
 357
 358         master = spi_alloc_master(&pdev->dev, sizeof(*bs));
 359         if (!master) {
 360                 ret = -ENOMEM;
 361                 goto out_disable_clk;
 362         }
 363
 364         bs = spi_master_get_devdata(master);
 365         bs->pdev = pdev;
 366         bs->clk = clk;
 367         bs->regs = regs;
 368         bs->speed_hz = rate;
 369         bs->fifo = (u8 __iomem *)(bs->regs + HSSPI_FIFO_REG(0));
 370
 371         mutex_init(&bs->bus_mutex);
 372
 373         master->bus_num = HSSPI_BUS_NUM;
 374         master->num_chipselect = 8;
 375         master->setup = bcm63xx_hsspi_setup;
 376         master->transfer_one_message = bcm63xx_hsspi_transfer_one;
 377         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 378         master->bits_per_word_mask = SPI_BPW_MASK(8);
 379         master->auto_runtime_pm = true;
 380
 381         platform_set_drvdata(pdev, master);
 382
 383         /* Initialize the hardware */
 384         __raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 385
 386         /* clean up any pending interrupts */
 387         __raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);
 388
 389         /* read out default CS polarities */
 390         reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 391         bs->cs_polarity = reg & GLOBAL_CTRL_CS_POLARITY_MASK;
 392         __raw_writel(reg | GLOBAL_CTRL_CLK_GATE_SSOFF,
 393                      bs->regs + HSSPI_GLOBAL_CTRL_REG);
 394
 395         ret = devm_request_irq(dev, irq, bcm63xx_hsspi_interrupt, IRQF_SHARED,
 396                                pdev->name, bs);
 397
 398         if (ret)
 399                 goto out_put_master;
 400
 401         /* register and we are done */
 402         ret = devm_spi_register_master(dev, master);
 403         if (ret)
 404                 goto out_put_master;
 405
 406         return 0;
 407
 408 out_put_master:
 409         spi_master_put(master);
 410 out_disable_clk:
 411         clk_disable_unprepare(clk);
 412         return ret;
 413 }
 414
 415
 416 static int bcm63xx_hsspi_remove(struct platform_device *pdev)
 417 {
 418         struct spi_master *master = platform_get_drvdata(pdev);
 419         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 420
 421         /* reset the hardware and block queue progress */
 422         __raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 423         clk_disable_unprepare(bs->clk);
 424
 425         return 0;
 426 }
 427
 428 #ifdef CONFIG_PM_SLEEP
 429 static int bcm63xx_hsspi_suspend(struct device *dev)
 430 {
 431         struct spi_master *master = dev_get_drvdata(dev);
 432         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 433
 434         spi_master_suspend(master);
 435         clk_disable_unprepare(bs->clk);
 436
 437         return 0;
 438 }
 439
 440 static int bcm63xx_hsspi_resume(struct device *dev)
 441 {
 442         struct spi_master *master = dev_get_drvdata(dev);
 443         struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 444         int ret;
 445
 446         ret = clk_prepare_enable(bs->clk);
 447         if (ret)
 448                 return ret;
 449
 450         spi_master_resume(master);
 451
 452         return 0;
 453 }
 454 #endif
 455
 456 static const struct dev_pm_ops bcm63xx_hsspi_pm_ops = {
 457         SET_SYSTEM_SLEEP_PM_OPS(bcm63xx_hsspi_suspend, bcm63xx_hsspi_resume)
 458 };
 459
 460 static struct platform_driver bcm63xx_hsspi_driver = {
 461         .driver = {
 462                 .name   = "bcm63xx-hsspi",
 463                 .owner  = THIS_MODULE,
 464                 .pm     = &bcm63xx_hsspi_pm_ops,
 465         },
 466         .probe          = bcm63xx_hsspi_probe,
 467         .remove         = bcm63xx_hsspi_remove,
 468 };
 469
 470 module_platform_driver(bcm63xx_hsspi_driver);
 471
 472 MODULE_ALIAS("platform:bcm63xx_hsspi");
 473 MODULE_DESCRIPTION("Broadcom BCM63xx High Speed SPI Controller driver");
 474 MODULE_AUTHOR("Jonas Gorski <jogo@openwrt.org>");
 475 MODULE_LICENSE("GPL");