drivers/spi/spi-xlp.c

   1 /*
   2  * Copyright (C) 2003-2015 Broadcom Corporation
   3  * All Rights Reserved
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 (GPL v2)
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14 #include <linux/acpi.h>
  15 #include <linux/clk.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/of.h>
  21 #include <linux/interrupt.h>
  22
  23 /* SPI Configuration Register */
  24 #define XLP_SPI_CONFIG                  0x00
  25 #define XLP_SPI_CPHA                    BIT(0)
  26 #define XLP_SPI_CPOL                    BIT(1)
  27 #define XLP_SPI_CS_POL                  BIT(2)
  28 #define XLP_SPI_TXMISO_EN               BIT(3)
  29 #define XLP_SPI_TXMOSI_EN               BIT(4)
  30 #define XLP_SPI_RXMISO_EN               BIT(5)
  31 #define XLP_SPI_CS_LSBFE                BIT(10)
  32 #define XLP_SPI_RXCAP_EN                BIT(11)
  33
  34 /* SPI Frequency Divider Register */
  35 #define XLP_SPI_FDIV                    0x04
  36
  37 /* SPI Command Register */
  38 #define XLP_SPI_CMD                     0x08
  39 #define XLP_SPI_CMD_IDLE_MASK           0x0
  40 #define XLP_SPI_CMD_TX_MASK             0x1
  41 #define XLP_SPI_CMD_RX_MASK             0x2
  42 #define XLP_SPI_CMD_TXRX_MASK           0x3
  43 #define XLP_SPI_CMD_CONT                BIT(4)
  44 #define XLP_SPI_XFR_BITCNT_SHIFT        16
  45
  46 /* SPI Status Register */
  47 #define XLP_SPI_STATUS                  0x0c
  48 #define XLP_SPI_XFR_PENDING             BIT(0)
  49 #define XLP_SPI_XFR_DONE                BIT(1)
  50 #define XLP_SPI_TX_INT                  BIT(2)
  51 #define XLP_SPI_RX_INT                  BIT(3)
  52 #define XLP_SPI_TX_UF                   BIT(4)
  53 #define XLP_SPI_RX_OF                   BIT(5)
  54 #define XLP_SPI_STAT_MASK               0x3f
  55
  56 /* SPI Interrupt Enable Register */
  57 #define XLP_SPI_INTR_EN                 0x10
  58 #define XLP_SPI_INTR_DONE               BIT(0)
  59 #define XLP_SPI_INTR_TXTH               BIT(1)
  60 #define XLP_SPI_INTR_RXTH               BIT(2)
  61 #define XLP_SPI_INTR_TXUF               BIT(3)
  62 #define XLP_SPI_INTR_RXOF               BIT(4)
  63
  64 /* SPI FIFO Threshold Register */
  65 #define XLP_SPI_FIFO_THRESH             0x14
  66
  67 /* SPI FIFO Word Count Register */
  68 #define XLP_SPI_FIFO_WCNT               0x18
  69 #define XLP_SPI_RXFIFO_WCNT_MASK        0xf
  70 #define XLP_SPI_TXFIFO_WCNT_MASK        0xf0
  71 #define XLP_SPI_TXFIFO_WCNT_SHIFT       4
  72
  73 /* SPI Transmit Data FIFO Register */
  74 #define XLP_SPI_TXDATA_FIFO             0x1c
  75
  76 /* SPI Receive Data FIFO Register */
  77 #define XLP_SPI_RXDATA_FIFO             0x20
  78
  79 /* SPI System Control Register */
  80 #define XLP_SPI_SYSCTRL                 0x100
  81 #define XLP_SPI_SYS_RESET               BIT(0)
  82 #define XLP_SPI_SYS_CLKDIS              BIT(1)
  83 #define XLP_SPI_SYS_PMEN                BIT(8)
  84
  85 #define SPI_CS_OFFSET                   0x40
  86 #define XLP_SPI_TXRXTH                  0x80
  87 #define XLP_SPI_FIFO_SIZE               8
  88 #define XLP_SPI_MAX_CS                  4
  89 #define XLP_SPI_DEFAULT_FREQ            133333333
  90 #define XLP_SPI_FDIV_MIN                4
  91 #define XLP_SPI_FDIV_MAX                65535
  92 /*
  93  * SPI can transfer only 28 bytes properly at a time. So split the
  94  * transfer into 28 bytes size.
  95  */
  96 #define XLP_SPI_XFER_SIZE               28
  97
  98 struct xlp_spi_priv {
  99         struct device           dev;            /* device structure */
 100         void __iomem            *base;          /* spi registers base address */
 101         const u8                *tx_buf;        /* tx data buffer */
 102         u8                      *rx_buf;        /* rx data buffer */
 103         int                     tx_len;         /* tx xfer length */
 104         int                     rx_len;         /* rx xfer length */
 105         int                     txerrors;       /* TXFIFO underflow count */
 106         int                     rxerrors;       /* RXFIFO overflow count */
 107         int                     cs;             /* slave device chip select */
 108         u32                     spi_clk;        /* spi clock frequency */
 109         bool                    cmd_cont;       /* cs active */
 110         struct completion       done;           /* completion notification */
 111 };
 112
 113 static inline u32 xlp_spi_reg_read(struct xlp_spi_priv *priv,
 114                                 int cs, int regoff)
 115 {
 116         return readl(priv->base + regoff + cs * SPI_CS_OFFSET);
 117 }
 118
 119 static inline void xlp_spi_reg_write(struct xlp_spi_priv *priv, int cs,
 120                                 int regoff, u32 val)
 121 {
 122         writel(val, priv->base + regoff + cs * SPI_CS_OFFSET);
 123 }
 124
 125 static inline void xlp_spi_sysctl_write(struct xlp_spi_priv *priv,
 126                                 int regoff, u32 val)
 127 {
 128         writel(val, priv->base + regoff);
 129 }
 130
 131 /*
 132  * Setup global SPI_SYSCTRL register for all SPI channels.
 133  */
 134 static void xlp_spi_sysctl_setup(struct xlp_spi_priv *xspi)
 135 {
 136         int cs;
 137
 138         for (cs = 0; cs < XLP_SPI_MAX_CS; cs++)
 139                 xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL,
 140                                 XLP_SPI_SYS_RESET << cs);
 141         xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL, XLP_SPI_SYS_PMEN);
 142 }
 143
 144 static int xlp_spi_setup(struct spi_device *spi)
 145 {
 146         struct xlp_spi_priv *xspi;
 147         u32 fdiv, cfg;
 148         int cs;
 149
 150         xspi = spi_master_get_devdata(spi->master);
 151         cs = spi->chip_select;
 152         /*
 153          * The value of fdiv must be between 4 and 65535.
 154          */
 155         fdiv = DIV_ROUND_UP(xspi->spi_clk, spi->max_speed_hz);
 156         if (fdiv > XLP_SPI_FDIV_MAX)
 157                 fdiv = XLP_SPI_FDIV_MAX;
 158         else if (fdiv < XLP_SPI_FDIV_MIN)
 159                 fdiv = XLP_SPI_FDIV_MIN;
 160
 161         xlp_spi_reg_write(xspi, cs, XLP_SPI_FDIV, fdiv);
 162         xlp_spi_reg_write(xspi, cs, XLP_SPI_FIFO_THRESH, XLP_SPI_TXRXTH);
 163         cfg = xlp_spi_reg_read(xspi, cs, XLP_SPI_CONFIG);
 164         if (spi->mode & SPI_CPHA)
 165                 cfg |= XLP_SPI_CPHA;
 166         else
 167                 cfg &= ~XLP_SPI_CPHA;
 168         if (spi->mode & SPI_CPOL)
 169                 cfg |= XLP_SPI_CPOL;
 170         else
 171                 cfg &= ~XLP_SPI_CPOL;
 172         if (!(spi->mode & SPI_CS_HIGH))
 173                 cfg |= XLP_SPI_CS_POL;
 174         else
 175                 cfg &= ~XLP_SPI_CS_POL;
 176         if (spi->mode & SPI_LSB_FIRST)
 177                 cfg |= XLP_SPI_CS_LSBFE;
 178         else
 179                 cfg &= ~XLP_SPI_CS_LSBFE;
 180
 181         cfg |= XLP_SPI_TXMOSI_EN | XLP_SPI_RXMISO_EN;
 182         if (fdiv == 4)
 183                 cfg |= XLP_SPI_RXCAP_EN;
 184         xlp_spi_reg_write(xspi, cs, XLP_SPI_CONFIG, cfg);
 185
 186         return 0;
 187 }
 188
 189 static void xlp_spi_read_rxfifo(struct xlp_spi_priv *xspi)
 190 {
 191         u32 rx_data, rxfifo_cnt;
 192         int i, j, nbytes;
 193
 194         rxfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
 195         rxfifo_cnt &= XLP_SPI_RXFIFO_WCNT_MASK;
 196         while (rxfifo_cnt) {
 197                 rx_data = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_RXDATA_FIFO);
 198                 j = 0;
 199                 nbytes = min(xspi->rx_len, 4);
 200                 for (i = nbytes - 1; i >= 0; i--, j++)
 201                         xspi->rx_buf[i] = (rx_data >> (j * 8)) & 0xff;
 202
 203                 xspi->rx_len -= nbytes;
 204                 xspi->rx_buf += nbytes;
 205                 rxfifo_cnt--;
 206         }
 207 }
 208
 209 static void xlp_spi_fill_txfifo(struct xlp_spi_priv *xspi)
 210 {
 211         u32 tx_data, txfifo_cnt;
 212         int i, j, nbytes;
 213
 214         txfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
 215         txfifo_cnt &= XLP_SPI_TXFIFO_WCNT_MASK;
 216         txfifo_cnt >>= XLP_SPI_TXFIFO_WCNT_SHIFT;
 217         while (xspi->tx_len && (txfifo_cnt < XLP_SPI_FIFO_SIZE)) {
 218                 j = 0;
 219                 tx_data = 0;
 220                 nbytes = min(xspi->tx_len, 4);
 221                 for (i = nbytes - 1; i >= 0; i--, j++)
 222                         tx_data |= xspi->tx_buf[i] << (j * 8);
 223
 224                 xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_TXDATA_FIFO, tx_data);
 225                 xspi->tx_len -= nbytes;
 226                 xspi->tx_buf += nbytes;
 227                 txfifo_cnt++;
 228         }
 229 }
 230
 231 static irqreturn_t xlp_spi_interrupt(int irq, void *dev_id)
 232 {
 233         struct xlp_spi_priv *xspi = dev_id;
 234         u32 stat;
 235
 236         stat = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_STATUS) &
 237                 XLP_SPI_STAT_MASK;
 238         if (!stat)
 239                 return IRQ_NONE;
 240
 241         if (stat & XLP_SPI_TX_INT) {
 242                 if (xspi->tx_len)
 243                         xlp_spi_fill_txfifo(xspi);
 244                 if (stat & XLP_SPI_TX_UF)
 245                         xspi->txerrors++;
 246         }
 247
 248         if (stat & XLP_SPI_RX_INT) {
 249                 if (xspi->rx_len)
 250                         xlp_spi_read_rxfifo(xspi);
 251                 if (stat & XLP_SPI_RX_OF)
 252                         xspi->rxerrors++;
 253         }
 254
 255         /* write status back to clear interrupts */
 256         xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_STATUS, stat);
 257         if (stat & XLP_SPI_XFR_DONE)
 258                 complete(&xspi->done);
 259
 260         return IRQ_HANDLED;
 261 }
 262
 263 static void xlp_spi_send_cmd(struct xlp_spi_priv *xspi, int xfer_len,
 264                         int cmd_cont)
 265 {
 266         u32 cmd = 0;
 267
 268         if (xspi->tx_buf)
 269                 cmd |= XLP_SPI_CMD_TX_MASK;
 270         if (xspi->rx_buf)
 271                 cmd |= XLP_SPI_CMD_RX_MASK;
 272         if (cmd_cont)
 273                 cmd |= XLP_SPI_CMD_CONT;
 274         cmd |= ((xfer_len * 8 - 1) << XLP_SPI_XFR_BITCNT_SHIFT);
 275         xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_CMD, cmd);
 276 }
 277
 278 static int xlp_spi_xfer_block(struct  xlp_spi_priv *xs,
 279                 const unsigned char *tx_buf,
 280                 unsigned char *rx_buf, int xfer_len, int cmd_cont)
 281 {
 282         int timeout;
 283         u32 intr_mask = 0;
 284
 285         xs->tx_buf = tx_buf;
 286         xs->rx_buf = rx_buf;
 287         xs->tx_len = (xs->tx_buf == NULL) ? 0 : xfer_len;
 288         xs->rx_len = (xs->rx_buf == NULL) ? 0 : xfer_len;
 289         xs->txerrors = xs->rxerrors = 0;
 290
 291         /* fill TXDATA_FIFO, then send the CMD */
 292         if (xs->tx_len)
 293                 xlp_spi_fill_txfifo(xs);
 294
 295         xlp_spi_send_cmd(xs, xfer_len, cmd_cont);
 296
 297         /*
 298          * We are getting some spurious tx interrupts, so avoid enabling
 299          * tx interrupts when only rx is in process.
 300          * Enable all the interrupts in tx case.
 301          */
 302         if (xs->tx_len)
 303                 intr_mask |= XLP_SPI_INTR_TXTH | XLP_SPI_INTR_TXUF |
 304                                 XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;
 305         else
 306                 intr_mask |= XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;
 307
 308         intr_mask |= XLP_SPI_INTR_DONE;
 309         xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, intr_mask);
 310
 311         timeout = wait_for_completion_timeout(&xs->done,
 312                                 msecs_to_jiffies(1000));
 313         /* Disable interrupts */
 314         xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, 0x0);
 315         if (!timeout) {
 316                 dev_err(&xs->dev, "xfer timedout!\n");
 317                 goto out;
 318         }
 319         if (xs->txerrors || xs->rxerrors)
 320                 dev_err(&xs->dev, "Over/Underflow rx %d tx %d xfer %d!\n",
 321                                 xs->rxerrors, xs->txerrors, xfer_len);
 322
 323         return xfer_len;
 324 out:
 325         return -ETIMEDOUT;
 326 }
 327
 328 static int xlp_spi_txrx_bufs(struct xlp_spi_priv *xs, struct spi_transfer *t)
 329 {
 330         int bytesleft, sz;
 331         unsigned char *rx_buf;
 332         const unsigned char *tx_buf;
 333
 334         tx_buf = t->tx_buf;
 335         rx_buf = t->rx_buf;
 336         bytesleft = t->len;
 337         while (bytesleft) {
 338                 if (bytesleft > XLP_SPI_XFER_SIZE)
 339                         sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
 340                                         XLP_SPI_XFER_SIZE, 1);
 341                 else
 342                         sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
 343                                         bytesleft, xs->cmd_cont);
 344                 if (sz < 0)
 345                         return sz;
 346                 bytesleft -= sz;
 347                 if (tx_buf)
 348                         tx_buf += sz;
 349                 if (rx_buf)
 350                         rx_buf += sz;
 351         }
 352         return bytesleft;
 353 }
 354
 355 static int xlp_spi_transfer_one(struct spi_master *master,
 356                                         struct spi_device *spi,
 357                                         struct spi_transfer *t)
 358 {
 359         struct xlp_spi_priv *xspi = spi_master_get_devdata(master);
 360         int ret = 0;
 361
 362         xspi->cs = spi->chip_select;
 363         xspi->dev = spi->dev;
 364
 365         if (spi_transfer_is_last(master, t))
 366                 xspi->cmd_cont = 0;
 367         else
 368                 xspi->cmd_cont = 1;
 369
 370         if (xlp_spi_txrx_bufs(xspi, t))
 371                 ret = -EIO;
 372
 373         spi_finalize_current_transfer(master);
 374         return ret;
 375 }
 376
 377 static int xlp_spi_probe(struct platform_device *pdev)
 378 {
 379         struct spi_master *master;
 380         struct xlp_spi_priv *xspi;
 381         struct resource *res;
 382         struct clk *clk;
 383         int irq, err;
 384
 385         xspi = devm_kzalloc(&pdev->dev, sizeof(*xspi), GFP_KERNEL);
 386         if (!xspi)
 387                 return -ENOMEM;
 388
 389         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 390         xspi->base = devm_ioremap_resource(&pdev->dev, res);
 391         if (IS_ERR(xspi->base))
 392                 return PTR_ERR(xspi->base);
 393
 394         irq = platform_get_irq(pdev, 0);
 395         if (irq < 0) {
 396                 dev_err(&pdev->dev, "no IRQ resource found\n");
 397                 return -EINVAL;
 398         }
 399         err = devm_request_irq(&pdev->dev, irq, xlp_spi_interrupt, 0,
 400                         pdev->name, xspi);
 401         if (err) {
 402                 dev_err(&pdev->dev, "unable to request irq %d\n", irq);
 403                 return err;
 404         }
 405
 406         clk = devm_clk_get(&pdev->dev, NULL);
 407         if (IS_ERR(clk)) {
 408                 dev_err(&pdev->dev, "could not get spi clock\n");
 409                 return PTR_ERR(clk);
 410         }
 411
 412         xspi->spi_clk = clk_get_rate(clk);
 413
 414         master = spi_alloc_master(&pdev->dev, 0);
 415         if (!master) {
 416                 dev_err(&pdev->dev, "could not alloc master\n");
 417                 return -ENOMEM;
 418         }
 419
 420         master->bus_num = 0;
 421         master->num_chipselect = XLP_SPI_MAX_CS;
 422         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 423         master->setup = xlp_spi_setup;
 424         master->transfer_one = xlp_spi_transfer_one;
 425         master->dev.of_node = pdev->dev.of_node;
 426
 427         init_completion(&xspi->done);
 428         spi_master_set_devdata(master, xspi);
 429         xlp_spi_sysctl_setup(xspi);
 430
 431         /* register spi controller */
 432         err = devm_spi_register_master(&pdev->dev, master);
 433         if (err) {
 434                 dev_err(&pdev->dev, "spi register master failed!\n");
 435                 spi_master_put(master);
 436                 return err;
 437         }
 438
 439         return 0;
 440 }
 441
 442 #ifdef CONFIG_ACPI
 443 static const struct acpi_device_id xlp_spi_acpi_match[] = {
 444         { "BRCM900D", 0 },
 445         { },
 446 };
 447 MODULE_DEVICE_TABLE(acpi, xlp_spi_acpi_match);
 448 #endif
 449
 450 static const struct of_device_id xlp_spi_dt_id[] = {
 451         { .compatible = "netlogic,xlp832-spi" },
 452         { },
 453 };
 454 MODULE_DEVICE_TABLE(of, xlp_spi_dt_id);
 455
 456 static struct platform_driver xlp_spi_driver = {
 457         .probe  = xlp_spi_probe,
 458         .driver = {
 459                 .name   = "xlp-spi",
 460                 .of_match_table = xlp_spi_dt_id,
 461                 .acpi_match_table = ACPI_PTR(xlp_spi_acpi_match),
 462         },
 463 };
 464 module_platform_driver(xlp_spi_driver);
 465
 466 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
 467 MODULE_DESCRIPTION("Netlogic XLP SPI controller driver");
 468 MODULE_LICENSE("GPL v2");