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/init.h>
  15 #include <linux/io.h>
  16 #include <linux/of.h>
  17
  18 #include <asm/octeon/octeon.h>
  19 #include <asm/octeon/cvmx-mpi-defs.h>
  20
  21 #define OCTEON_SPI_CFG 0
  22 #define OCTEON_SPI_STS 0x08
  23 #define OCTEON_SPI_TX 0x10
  24 #define OCTEON_SPI_DAT0 0x80
  25
  26 #define OCTEON_SPI_MAX_BYTES 9
  27
  28 #define OCTEON_SPI_MAX_CLOCK_HZ 16000000
  29
  30 struct octeon_spi {
  31         u64 register_base;
  32         u64 last_cfg;
  33         u64 cs_enax;
  34 };
  35
  36 struct octeon_spi_setup {
  37         u32 max_speed_hz;
  38         u8 chip_select;
  39         u8 mode;
  40         u8 bits_per_word;
  41 };
  42
  43 static void octeon_spi_wait_ready(struct octeon_spi *p)
  44 {
  45         union cvmx_mpi_sts mpi_sts;
  46         unsigned int loops = 0;
  47
  48         do {
  49                 if (loops++)
  50                         __delay(500);
  51                 mpi_sts.u64 = cvmx_read_csr(p->register_base + OCTEON_SPI_STS);
  52         } while (mpi_sts.s.busy);
  53 }
  54
  55 static int octeon_spi_do_transfer(struct octeon_spi *p,
  56                                   struct spi_message *msg,
  57                                   struct spi_transfer *xfer,
  58                                   bool last_xfer)
  59 {
  60         union cvmx_mpi_cfg mpi_cfg;
  61         union cvmx_mpi_tx mpi_tx;
  62         unsigned int clkdiv;
  63         unsigned int speed_hz;
  64         int mode;
  65         bool cpha, cpol;
  66         const u8 *tx_buf;
  67         u8 *rx_buf;
  68         int len;
  69         int i;
  70
  71         struct octeon_spi_setup *msg_setup = spi_get_ctldata(msg->spi);
  72
  73         speed_hz = msg_setup->max_speed_hz;
  74         mode = msg_setup->mode;
  75         cpha = mode & SPI_CPHA;
  76         cpol = mode & SPI_CPOL;
  77
  78         if (xfer->speed_hz)
  79                 speed_hz = xfer->speed_hz;
  80
  81         if (speed_hz > OCTEON_SPI_MAX_CLOCK_HZ)
  82                 speed_hz = OCTEON_SPI_MAX_CLOCK_HZ;
  83
  84         clkdiv = octeon_get_io_clock_rate() / (2 * speed_hz);
  85
  86         mpi_cfg.u64 = 0;
  87
  88         mpi_cfg.s.clkdiv = clkdiv;
  89         mpi_cfg.s.cshi = (mode & SPI_CS_HIGH) ? 1 : 0;
  90         mpi_cfg.s.lsbfirst = (mode & SPI_LSB_FIRST) ? 1 : 0;
  91         mpi_cfg.s.wireor = (mode & SPI_3WIRE) ? 1 : 0;
  92         mpi_cfg.s.idlelo = cpha != cpol;
  93         mpi_cfg.s.cslate = cpha ? 1 : 0;
  94         mpi_cfg.s.enable = 1;
  95
  96         if (msg_setup->chip_select < 4)
  97                 p->cs_enax |= 1ull << (12 + msg_setup->chip_select);
  98         mpi_cfg.u64 |= p->cs_enax;
  99
 100         if (mpi_cfg.u64 != p->last_cfg) {
 101                 p->last_cfg = mpi_cfg.u64;
 102                 cvmx_write_csr(p->register_base + OCTEON_SPI_CFG, mpi_cfg.u64);
 103         }
 104         tx_buf = xfer->tx_buf;
 105         rx_buf = xfer->rx_buf;
 106         len = xfer->len;
 107         while (len > OCTEON_SPI_MAX_BYTES) {
 108                 for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
 109                         u8 d;
 110                         if (tx_buf)
 111                                 d = *tx_buf++;
 112                         else
 113                                 d = 0;
 114                         cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d);
 115                 }
 116                 mpi_tx.u64 = 0;
 117                 mpi_tx.s.csid = msg_setup->chip_select;
 118                 mpi_tx.s.leavecs = 1;
 119                 mpi_tx.s.txnum = tx_buf ? OCTEON_SPI_MAX_BYTES : 0;
 120                 mpi_tx.s.totnum = OCTEON_SPI_MAX_BYTES;
 121                 cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64);
 122
 123                 octeon_spi_wait_ready(p);
 124                 if (rx_buf)
 125                         for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
 126                                 u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i));
 127                                 *rx_buf++ = (u8)v;
 128                         }
 129                 len -= OCTEON_SPI_MAX_BYTES;
 130         }
 131
 132         for (i = 0; i < len; i++) {
 133                 u8 d;
 134                 if (tx_buf)
 135                         d = *tx_buf++;
 136                 else
 137                         d = 0;
 138                 cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d);
 139         }
 140
 141         mpi_tx.u64 = 0;
 142         mpi_tx.s.csid = msg_setup->chip_select;
 143         if (last_xfer)
 144                 mpi_tx.s.leavecs = xfer->cs_change;
 145         else
 146                 mpi_tx.s.leavecs = !xfer->cs_change;
 147         mpi_tx.s.txnum = tx_buf ? len : 0;
 148         mpi_tx.s.totnum = len;
 149         cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64);
 150
 151         octeon_spi_wait_ready(p);
 152         if (rx_buf)
 153                 for (i = 0; i < len; i++) {
 154                         u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i));
 155                         *rx_buf++ = (u8)v;
 156                 }
 157
 158         if (xfer->delay_usecs)
 159                 udelay(xfer->delay_usecs);
 160
 161         return xfer->len;
 162 }
 163
 164 static int octeon_spi_transfer_one_message(struct spi_master *master,
 165                                            struct spi_message *msg)
 166 {
 167         struct octeon_spi *p = spi_master_get_devdata(master);
 168         unsigned int total_len = 0;
 169         int status = 0;
 170         struct spi_transfer *xfer;
 171
 172         /*
 173          * We better have set the configuration via a call to .setup
 174          * before we get here.
 175          */
 176         if (spi_get_ctldata(msg->spi) == NULL) {
 177                 status = -EINVAL;
 178                 goto err;
 179         }
 180
 181         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 182                 bool last_xfer = &xfer->transfer_list == msg->transfers.prev;
 183                 int r = octeon_spi_do_transfer(p, msg, xfer, last_xfer);
 184                 if (r < 0) {
 185                         status = r;
 186                         goto err;
 187                 }
 188                 total_len += r;
 189         }
 190 err:
 191         msg->status = status;
 192         msg->actual_length = total_len;
 193         spi_finalize_current_message(master);
 194         return status;
 195 }
 196
 197 static struct octeon_spi_setup *octeon_spi_new_setup(struct spi_device *spi)
 198 {
 199         struct octeon_spi_setup *setup = kzalloc(sizeof(*setup), GFP_KERNEL);
 200         if (!setup)
 201                 return NULL;
 202
 203         setup->max_speed_hz = spi->max_speed_hz;
 204         setup->chip_select = spi->chip_select;
 205         setup->mode = spi->mode;
 206         setup->bits_per_word = spi->bits_per_word;
 207         return setup;
 208 }
 209
 210 static int octeon_spi_setup(struct spi_device *spi)
 211 {
 212         struct octeon_spi_setup *new_setup;
 213         struct octeon_spi_setup *old_setup = spi_get_ctldata(spi);
 214
 215         new_setup = octeon_spi_new_setup(spi);
 216         if (!new_setup)
 217                 return -ENOMEM;
 218
 219         spi_set_ctldata(spi, new_setup);
 220         kfree(old_setup);
 221
 222         return 0;
 223 }
 224
 225 static void octeon_spi_cleanup(struct spi_device *spi)
 226 {
 227         struct octeon_spi_setup *old_setup = spi_get_ctldata(spi);
 228         spi_set_ctldata(spi, NULL);
 229         kfree(old_setup);
 230 }
 231
 232 static int octeon_spi_probe(struct platform_device *pdev)
 233 {
 234         struct resource *res_mem;
 235         struct spi_master *master;
 236         struct octeon_spi *p;
 237         int err = -ENOENT;
 238
 239         master = spi_alloc_master(&pdev->dev, sizeof(struct octeon_spi));
 240         if (!master)
 241                 return -ENOMEM;
 242         p = spi_master_get_devdata(master);
 243         platform_set_drvdata(pdev, master);
 244
 245         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 246
 247         if (res_mem == NULL) {
 248                 dev_err(&pdev->dev, "found no memory resource\n");
 249                 err = -ENXIO;
 250                 goto fail;
 251         }
 252         if (!devm_request_mem_region(&pdev->dev, res_mem->start,
 253                                      resource_size(res_mem), res_mem->name)) {
 254                 dev_err(&pdev->dev, "request_mem_region failed\n");
 255                 goto fail;
 256         }
 257         p->register_base = (u64)devm_ioremap(&pdev->dev, res_mem->start,
 258                                              resource_size(res_mem));
 259
 260         /* Dynamic bus numbering */
 261         master->bus_num = -1;
 262         master->num_chipselect = 4;
 263         master->mode_bits = SPI_CPHA |
 264                             SPI_CPOL |
 265                             SPI_CS_HIGH |
 266                             SPI_LSB_FIRST |
 267                             SPI_3WIRE;
 268
 269         master->setup = octeon_spi_setup;
 270         master->cleanup = octeon_spi_cleanup;
 271         master->transfer_one_message = octeon_spi_transfer_one_message;
 272         master->bits_per_word_mask = SPI_BPW_MASK(8);
 273
 274         master->dev.of_node = pdev->dev.of_node;
 275         err = spi_register_master(master);
 276         if (err) {
 277                 dev_err(&pdev->dev, "register master failed: %d\n", err);
 278                 goto fail;
 279         }
 280
 281         dev_info(&pdev->dev, "OCTEON SPI bus driver\n");
 282
 283         return 0;
 284 fail:
 285         spi_master_put(master);
 286         return err;
 287 }
 288
 289 static int octeon_spi_remove(struct platform_device *pdev)
 290 {
 291         struct spi_master *master = platform_get_drvdata(pdev);
 292         struct octeon_spi *p = spi_master_get_devdata(master);
 293         u64 register_base = p->register_base;
 294
 295         spi_unregister_master(master);
 296
 297         /* Clear the CSENA* and put everything in a known state. */
 298         cvmx_write_csr(register_base + OCTEON_SPI_CFG, 0);
 299
 300         return 0;
 301 }
 302
 303 static struct of_device_id octeon_spi_match[] = {
 304         { .compatible = "cavium,octeon-3010-spi", },
 305         {},
 306 };
 307 MODULE_DEVICE_TABLE(of, octeon_spi_match);
 308
 309 static struct platform_driver octeon_spi_driver = {
 310         .driver = {
 311                 .name           = "spi-octeon",
 312                 .owner          = THIS_MODULE,
 313                 .of_match_table = octeon_spi_match,
 314         },
 315         .probe          = octeon_spi_probe,
 316         .remove         = octeon_spi_remove,
 317 };
 318
 319 module_platform_driver(octeon_spi_driver);
 320
 321 MODULE_DESCRIPTION("Cavium, Inc. OCTEON SPI bus driver");
 322 MODULE_AUTHOR("David Daney");
 323 MODULE_LICENSE("GPL");