drivers/spi/spi-octeon.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2011, 2012 Cavium, Inc.
   7  */
   8
   9 #include <linux/platform_device.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/module.h>
  13 #include <linux/delay.h>
  14 #include <linux/io.h>
  15 #include <linux/of.h>
  16
  17 #include <asm/octeon/octeon.h>
  18 #include <asm/octeon/cvmx-mpi-defs.h>
  19
  20 #define OCTEON_SPI_CFG 0
  21 #define OCTEON_SPI_STS 0x08
  22 #define OCTEON_SPI_TX 0x10
  23 #define OCTEON_SPI_DAT0 0x80
  24
  25 #define OCTEON_SPI_MAX_BYTES 9
  26
  27 #define OCTEON_SPI_MAX_CLOCK_HZ 16000000
  28
  29 struct octeon_spi {
  30         u64 register_base;
  31         u64 last_cfg;
  32         u64 cs_enax;
  33 };
  34
  35 static void octeon_spi_wait_ready(struct octeon_spi *p)
  36 {
  37         union cvmx_mpi_sts mpi_sts;
  38         unsigned int loops = 0;
  39
  40         do {
  41                 if (loops++)
  42                         __delay(500);
  43                 mpi_sts.u64 = cvmx_read_csr(p->register_base + OCTEON_SPI_STS);
  44         } while (mpi_sts.s.busy);
  45 }
  46
  47 static int octeon_spi_do_transfer(struct octeon_spi *p,
  48                                   struct spi_message *msg,
  49                                   struct spi_transfer *xfer,
  50                                   bool last_xfer)
  51 {
  52         struct spi_device *spi = msg->spi;
  53         union cvmx_mpi_cfg mpi_cfg;
  54         union cvmx_mpi_tx mpi_tx;
  55         unsigned int clkdiv;
  56         unsigned int speed_hz;
  57         int mode;
  58         bool cpha, cpol;
  59         const u8 *tx_buf;
  60         u8 *rx_buf;
  61         int len;
  62         int i;
  63
  64         mode = spi->mode;
  65         cpha = mode & SPI_CPHA;
  66         cpol = mode & SPI_CPOL;
  67
  68         speed_hz = xfer->speed_hz;
  69
  70         clkdiv = octeon_get_io_clock_rate() / (2 * speed_hz);
  71
  72         mpi_cfg.u64 = 0;
  73
  74         mpi_cfg.s.clkdiv = clkdiv;
  75         mpi_cfg.s.cshi = (mode & SPI_CS_HIGH) ? 1 : 0;
  76         mpi_cfg.s.lsbfirst = (mode & SPI_LSB_FIRST) ? 1 : 0;
  77         mpi_cfg.s.wireor = (mode & SPI_3WIRE) ? 1 : 0;
  78         mpi_cfg.s.idlelo = cpha != cpol;
  79         mpi_cfg.s.cslate = cpha ? 1 : 0;
  80         mpi_cfg.s.enable = 1;
  81
  82         if (spi->chip_select < 4)
  83                 p->cs_enax |= 1ull << (12 + spi->chip_select);
  84         mpi_cfg.u64 |= p->cs_enax;
  85
  86         if (mpi_cfg.u64 != p->last_cfg) {
  87                 p->last_cfg = mpi_cfg.u64;
  88                 cvmx_write_csr(p->register_base + OCTEON_SPI_CFG, mpi_cfg.u64);
  89         }
  90         tx_buf = xfer->tx_buf;
  91         rx_buf = xfer->rx_buf;
  92         len = xfer->len;
  93         while (len > OCTEON_SPI_MAX_BYTES) {
  94                 for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
  95                         u8 d;
  96                         if (tx_buf)
  97                                 d = *tx_buf++;
  98                         else
  99                                 d = 0;
 100                         cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d);
 101                 }
 102                 mpi_tx.u64 = 0;
 103                 mpi_tx.s.csid = spi->chip_select;
 104                 mpi_tx.s.leavecs = 1;
 105                 mpi_tx.s.txnum = tx_buf ? OCTEON_SPI_MAX_BYTES : 0;
 106                 mpi_tx.s.totnum = OCTEON_SPI_MAX_BYTES;
 107                 cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64);
 108
 109                 octeon_spi_wait_ready(p);
 110                 if (rx_buf)
 111                         for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
 112                                 u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i));
 113                                 *rx_buf++ = (u8)v;
 114                         }
 115                 len -= OCTEON_SPI_MAX_BYTES;
 116         }
 117
 118         for (i = 0; i < len; i++) {
 119                 u8 d;
 120                 if (tx_buf)
 121                         d = *tx_buf++;
 122                 else
 123                         d = 0;
 124                 cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d);
 125         }
 126
 127         mpi_tx.u64 = 0;
 128         mpi_tx.s.csid = spi->chip_select;
 129         if (last_xfer)
 130                 mpi_tx.s.leavecs = xfer->cs_change;
 131         else
 132                 mpi_tx.s.leavecs = !xfer->cs_change;
 133         mpi_tx.s.txnum = tx_buf ? len : 0;
 134         mpi_tx.s.totnum = len;
 135         cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64);
 136
 137         octeon_spi_wait_ready(p);
 138         if (rx_buf)
 139                 for (i = 0; i < len; i++) {
 140                         u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i));
 141                         *rx_buf++ = (u8)v;
 142                 }
 143
 144         if (xfer->delay_usecs)
 145                 udelay(xfer->delay_usecs);
 146
 147         return xfer->len;
 148 }
 149
 150 static int octeon_spi_transfer_one_message(struct spi_master *master,
 151                                            struct spi_message *msg)
 152 {
 153         struct octeon_spi *p = spi_master_get_devdata(master);
 154         unsigned int total_len = 0;
 155         int status = 0;
 156         struct spi_transfer *xfer;
 157
 158         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 159                 bool last_xfer = list_is_last(&xfer->transfer_list,
 160                                               &msg->transfers);
 161                 int r = octeon_spi_do_transfer(p, msg, xfer, last_xfer);
 162                 if (r < 0) {
 163                         status = r;
 164                         goto err;
 165                 }
 166                 total_len += r;
 167         }
 168 err:
 169         msg->status = status;
 170         msg->actual_length = total_len;
 171         spi_finalize_current_message(master);
 172         return status;
 173 }
 174
 175 static int octeon_spi_probe(struct platform_device *pdev)
 176 {
 177         struct resource *res_mem;
 178         void __iomem *reg_base;
 179         struct spi_master *master;
 180         struct octeon_spi *p;
 181         int err = -ENOENT;
 182
 183         master = spi_alloc_master(&pdev->dev, sizeof(struct octeon_spi));
 184         if (!master)
 185                 return -ENOMEM;
 186         p = spi_master_get_devdata(master);
 187         platform_set_drvdata(pdev, master);
 188
 189         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 190         reg_base = devm_ioremap_resource(&pdev->dev, res_mem);
 191         if (IS_ERR(reg_base)) {
 192                 err = PTR_ERR(reg_base);
 193                 goto fail;
 194         }
 195
 196         p->register_base = (u64)reg_base;
 197
 198         master->num_chipselect = 4;
 199         master->mode_bits = SPI_CPHA |
 200                             SPI_CPOL |
 201                             SPI_CS_HIGH |
 202                             SPI_LSB_FIRST |
 203                             SPI_3WIRE;
 204
 205         master->transfer_one_message = octeon_spi_transfer_one_message;
 206         master->bits_per_word_mask = SPI_BPW_MASK(8);
 207         master->max_speed_hz = OCTEON_SPI_MAX_CLOCK_HZ;
 208
 209         master->dev.of_node = pdev->dev.of_node;
 210         err = devm_spi_register_master(&pdev->dev, master);
 211         if (err) {
 212                 dev_err(&pdev->dev, "register master failed: %d\n", err);
 213                 goto fail;
 214         }
 215
 216         dev_info(&pdev->dev, "OCTEON SPI bus driver\n");
 217
 218         return 0;
 219 fail:
 220         spi_master_put(master);
 221         return err;
 222 }
 223
 224 static int octeon_spi_remove(struct platform_device *pdev)
 225 {
 226         struct spi_master *master = platform_get_drvdata(pdev);
 227         struct octeon_spi *p = spi_master_get_devdata(master);
 228         u64 register_base = p->register_base;
 229
 230         /* Clear the CSENA* and put everything in a known state. */
 231         cvmx_write_csr(register_base + OCTEON_SPI_CFG, 0);
 232
 233         return 0;
 234 }
 235
 236 static const struct of_device_id octeon_spi_match[] = {
 237         { .compatible = "cavium,octeon-3010-spi", },
 238         {},
 239 };
 240 MODULE_DEVICE_TABLE(of, octeon_spi_match);
 241
 242 static struct platform_driver octeon_spi_driver = {
 243         .driver = {
 244                 .name           = "spi-octeon",
 245                 .of_match_table = octeon_spi_match,
 246         },
 247         .probe          = octeon_spi_probe,
 248         .remove         = octeon_spi_remove,
 249 };
 250
 251 module_platform_driver(octeon_spi_driver);
 252
 253 MODULE_DESCRIPTION("Cavium, Inc. OCTEON SPI bus driver");
 254 MODULE_AUTHOR("David Daney");
 255 MODULE_LICENSE("GPL");