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         struct spi_master *my_master;
  32         u64 register_base;
  33         u64 last_cfg;
  34         u64 cs_enax;
  35 };
  36
  37 struct octeon_spi_setup {
  38         u32 max_speed_hz;
  39         u8 chip_select;
  40         u8 mode;
  41         u8 bits_per_word;
  42 };
  43
  44 static void octeon_spi_wait_ready(struct octeon_spi *p)
  45 {
  46         union cvmx_mpi_sts mpi_sts;
  47         unsigned int loops = 0;
  48
  49         do {
  50                 if (loops++)
  51                         __delay(500);
  52                 mpi_sts.u64 = cvmx_read_csr(p->register_base + OCTEON_SPI_STS);
  53         } while (mpi_sts.s.busy);
  54 }
  55
  56 static int octeon_spi_do_transfer(struct octeon_spi *p,
  57                                   struct spi_message *msg,
  58                                   struct spi_transfer *xfer,
  59                                   bool last_xfer)
  60 {
  61         union cvmx_mpi_cfg mpi_cfg;
  62         union cvmx_mpi_tx mpi_tx;
  63         unsigned int clkdiv;
  64         unsigned int speed_hz;
  65         int mode;
  66         bool cpha, cpol;
  67         int bits_per_word;
  68         const u8 *tx_buf;
  69         u8 *rx_buf;
  70         int len;
  71         int i;
  72
  73         struct octeon_spi_setup *msg_setup = spi_get_ctldata(msg->spi);
  74
  75         speed_hz = msg_setup->max_speed_hz;
  76         mode = msg_setup->mode;
  77         cpha = mode & SPI_CPHA;
  78         cpol = mode & SPI_CPOL;
  79         bits_per_word = msg_setup->bits_per_word;
  80
  81         if (xfer->speed_hz)
  82                 speed_hz = xfer->speed_hz;
  83         if (xfer->bits_per_word)
  84                 bits_per_word = xfer->bits_per_word;
  85
  86         if (speed_hz > OCTEON_SPI_MAX_CLOCK_HZ)
  87                 speed_hz = OCTEON_SPI_MAX_CLOCK_HZ;
  88
  89         clkdiv = octeon_get_io_clock_rate() / (2 * speed_hz);
  90
  91         mpi_cfg.u64 = 0;
  92
  93         mpi_cfg.s.clkdiv = clkdiv;
  94         mpi_cfg.s.cshi = (mode & SPI_CS_HIGH) ? 1 : 0;
  95         mpi_cfg.s.lsbfirst = (mode & SPI_LSB_FIRST) ? 1 : 0;
  96         mpi_cfg.s.wireor = (mode & SPI_3WIRE) ? 1 : 0;
  97         mpi_cfg.s.idlelo = cpha != cpol;
  98         mpi_cfg.s.cslate = cpha ? 1 : 0;
  99         mpi_cfg.s.enable = 1;
 100
 101         if (msg_setup->chip_select < 4)
 102                 p->cs_enax |= 1ull << (12 + msg_setup->chip_select);
 103         mpi_cfg.u64 |= p->cs_enax;
 104
 105         if (mpi_cfg.u64 != p->last_cfg) {
 106                 p->last_cfg = mpi_cfg.u64;
 107                 cvmx_write_csr(p->register_base + OCTEON_SPI_CFG, mpi_cfg.u64);
 108         }
 109         tx_buf = xfer->tx_buf;
 110         rx_buf = xfer->rx_buf;
 111         len = xfer->len;
 112         while (len > OCTEON_SPI_MAX_BYTES) {
 113                 for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
 114                         u8 d;
 115                         if (tx_buf)
 116                                 d = *tx_buf++;
 117                         else
 118                                 d = 0;
 119                         cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d);
 120                 }
 121                 mpi_tx.u64 = 0;
 122                 mpi_tx.s.csid = msg_setup->chip_select;
 123                 mpi_tx.s.leavecs = 1;
 124                 mpi_tx.s.txnum = tx_buf ? OCTEON_SPI_MAX_BYTES : 0;
 125                 mpi_tx.s.totnum = OCTEON_SPI_MAX_BYTES;
 126                 cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64);
 127
 128                 octeon_spi_wait_ready(p);
 129                 if (rx_buf)
 130                         for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
 131                                 u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i));
 132                                 *rx_buf++ = (u8)v;
 133                         }
 134                 len -= OCTEON_SPI_MAX_BYTES;
 135         }
 136
 137         for (i = 0; i < len; i++) {
 138                 u8 d;
 139                 if (tx_buf)
 140                         d = *tx_buf++;
 141                 else
 142                         d = 0;
 143                 cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d);
 144         }
 145
 146         mpi_tx.u64 = 0;
 147         mpi_tx.s.csid = msg_setup->chip_select;
 148         if (last_xfer)
 149                 mpi_tx.s.leavecs = xfer->cs_change;
 150         else
 151                 mpi_tx.s.leavecs = !xfer->cs_change;
 152         mpi_tx.s.txnum = tx_buf ? len : 0;
 153         mpi_tx.s.totnum = len;
 154         cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64);
 155
 156         octeon_spi_wait_ready(p);
 157         if (rx_buf)
 158                 for (i = 0; i < len; i++) {
 159                         u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i));
 160                         *rx_buf++ = (u8)v;
 161                 }
 162
 163         if (xfer->delay_usecs)
 164                 udelay(xfer->delay_usecs);
 165
 166         return xfer->len;
 167 }
 168
 169 static int octeon_spi_validate_bpw(struct spi_device *spi, u32 speed)
 170 {
 171         switch (speed) {
 172         case 8:
 173                 break;
 174         default:
 175                 dev_err(&spi->dev, "Error: %d bits per word not supported\n",
 176                         speed);
 177                 return -EINVAL;
 178         }
 179         return 0;
 180 }
 181
 182 static int octeon_spi_transfer_one_message(struct spi_master *master,
 183                                            struct spi_message *msg)
 184 {
 185         struct octeon_spi *p = spi_master_get_devdata(master);
 186         unsigned int total_len = 0;
 187         int status = 0;
 188         struct spi_transfer *xfer;
 189
 190         /*
 191          * We better have set the configuration via a call to .setup
 192          * before we get here.
 193          */
 194         if (spi_get_ctldata(msg->spi) == NULL) {
 195                 status = -EINVAL;
 196                 goto err;
 197         }
 198
 199         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 200                 if (xfer->bits_per_word) {
 201                         status = octeon_spi_validate_bpw(msg->spi,
 202                                                          xfer->bits_per_word);
 203                         if (status)
 204                                 goto err;
 205                 }
 206         }
 207
 208         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 209                 bool last_xfer = &xfer->transfer_list == msg->transfers.prev;
 210                 int r = octeon_spi_do_transfer(p, msg, xfer, last_xfer);
 211                 if (r < 0) {
 212                         status = r;
 213                         goto err;
 214                 }
 215                 total_len += r;
 216         }
 217 err:
 218         msg->status = status;
 219         msg->actual_length = total_len;
 220         spi_finalize_current_message(master);
 221         return status;
 222 }
 223
 224 static struct octeon_spi_setup *octeon_spi_new_setup(struct spi_device *spi)
 225 {
 226         struct octeon_spi_setup *setup = kzalloc(sizeof(*setup), GFP_KERNEL);
 227         if (!setup)
 228                 return NULL;
 229
 230         setup->max_speed_hz = spi->max_speed_hz;
 231         setup->chip_select = spi->chip_select;
 232         setup->mode = spi->mode;
 233         setup->bits_per_word = spi->bits_per_word;
 234         return setup;
 235 }
 236
 237 static int octeon_spi_setup(struct spi_device *spi)
 238 {
 239         int r;
 240         struct octeon_spi_setup *new_setup;
 241         struct octeon_spi_setup *old_setup = spi_get_ctldata(spi);
 242
 243         r = octeon_spi_validate_bpw(spi, spi->bits_per_word);
 244         if (r)
 245                 return r;
 246
 247         new_setup = octeon_spi_new_setup(spi);
 248         if (!new_setup)
 249                 return -ENOMEM;
 250
 251         spi_set_ctldata(spi, new_setup);
 252         kfree(old_setup);
 253
 254         return 0;
 255 }
 256
 257 static void octeon_spi_cleanup(struct spi_device *spi)
 258 {
 259         struct octeon_spi_setup *old_setup = spi_get_ctldata(spi);
 260         spi_set_ctldata(spi, NULL);
 261         kfree(old_setup);
 262 }
 263
 264 static int octeon_spi_nop_transfer_hardware(struct spi_master *master)
 265 {
 266         return 0;
 267 }
 268
 269 static int octeon_spi_probe(struct platform_device *pdev)
 270 {
 271
 272         struct resource *res_mem;
 273         struct spi_master *master;
 274         struct octeon_spi *p;
 275         int err = -ENOENT;
 276
 277         master = spi_alloc_master(&pdev->dev, sizeof(struct octeon_spi));
 278         if (!master)
 279                 return -ENOMEM;
 280         p = spi_master_get_devdata(master);
 281         platform_set_drvdata(pdev, p);
 282         p->my_master = master;
 283
 284         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 285
 286         if (res_mem == NULL) {
 287                 dev_err(&pdev->dev, "found no memory resource\n");
 288                 err = -ENXIO;
 289                 goto fail;
 290         }
 291         if (!devm_request_mem_region(&pdev->dev, res_mem->start,
 292                                      resource_size(res_mem), res_mem->name)) {
 293                 dev_err(&pdev->dev, "request_mem_region failed\n");
 294                 goto fail;
 295         }
 296         p->register_base = (u64)devm_ioremap(&pdev->dev, res_mem->start,
 297                                              resource_size(res_mem));
 298
 299         /* Dynamic bus numbering */
 300         master->bus_num = -1;
 301         master->num_chipselect = 4;
 302         master->mode_bits = SPI_CPHA |
 303                             SPI_CPOL |
 304                             SPI_CS_HIGH |
 305                             SPI_LSB_FIRST |
 306                             SPI_3WIRE;
 307
 308         master->setup = octeon_spi_setup;
 309         master->cleanup = octeon_spi_cleanup;
 310         master->prepare_transfer_hardware = octeon_spi_nop_transfer_hardware;
 311         master->transfer_one_message = octeon_spi_transfer_one_message;
 312         master->unprepare_transfer_hardware = octeon_spi_nop_transfer_hardware;
 313
 314         master->dev.of_node = pdev->dev.of_node;
 315         err = spi_register_master(master);
 316         if (err) {
 317                 dev_err(&pdev->dev, "register master failed: %d\n", err);
 318                 goto fail;
 319         }
 320
 321         dev_info(&pdev->dev, "OCTEON SPI bus driver\n");
 322
 323         return 0;
 324 fail:
 325         spi_master_put(master);
 326         return err;
 327 }
 328
 329 static int octeon_spi_remove(struct platform_device *pdev)
 330 {
 331         struct octeon_spi *p = platform_get_drvdata(pdev);
 332         u64 register_base = p->register_base;
 333
 334         spi_unregister_master(p->my_master);
 335
 336         /* Clear the CSENA* and put everything in a known state. */
 337         cvmx_write_csr(register_base + OCTEON_SPI_CFG, 0);
 338
 339         return 0;
 340 }
 341
 342 static struct of_device_id octeon_spi_match[] = {
 343         { .compatible = "cavium,octeon-3010-spi", },
 344         {},
 345 };
 346 MODULE_DEVICE_TABLE(of, octeon_spi_match);
 347
 348 static struct platform_driver octeon_spi_driver = {
 349         .driver = {
 350                 .name           = "spi-octeon",
 351                 .owner          = THIS_MODULE,
 352                 .of_match_table = octeon_spi_match,
 353         },
 354         .probe          = octeon_spi_probe,
 355         .remove         = octeon_spi_remove,
 356 };
 357
 358 module_platform_driver(octeon_spi_driver);
 359
 360 MODULE_DESCRIPTION("Cavium, Inc. OCTEON SPI bus driver");
 361 MODULE_AUTHOR("David Daney");
 362 MODULE_LICENSE("GPL");