sound/soc/sh/siu_pcm.c

   1 /*
   2  * siu_pcm.c - ALSA driver for Renesas SH7343, SH7722 SIU peripheral.
   3  *
   4  * Copyright (C) 2009-2010 Guennadi Liakhovetski <g.liakhovetski@gmx.de>
   5  * Copyright (C) 2006 Carlos Munoz <carlos@kenati.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21 #include <linux/delay.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/module.h>
  26 #include <linux/platform_device.h>
  27
  28 #include <sound/control.h>
  29 #include <sound/core.h>
  30 #include <sound/pcm.h>
  31 #include <sound/pcm_params.h>
  32 #include <sound/soc-dai.h>
  33
  34 #include <asm/siu.h>
  35
  36 #include "siu.h"
  37
  38 #define GET_MAX_PERIODS(buf_bytes, period_bytes) \
  39                                 ((buf_bytes) / (period_bytes))
  40 #define PERIOD_OFFSET(buf_addr, period_num, period_bytes) \
  41                                 ((buf_addr) + ((period_num) * (period_bytes)))
  42
  43 #define RWF_STM_RD              0x01            /* Read in progress */
  44 #define RWF_STM_WT              0x02            /* Write in progress */
  45
  46 struct siu_port *siu_ports[SIU_PORT_NUM];
  47
  48 /* transfersize is number of u32 dma transfers per period */
  49 static int siu_pcm_stmwrite_stop(struct siu_port *port_info)
  50 {
  51         struct siu_info *info = siu_i2s_dai.private_data;
  52         u32 __iomem *base = info->reg;
  53         struct siu_stream *siu_stream = &port_info->playback;
  54         u32 stfifo;
  55
  56         if (!siu_stream->rw_flg)
  57                 return -EPERM;
  58
  59         /* output FIFO disable */
  60         stfifo = siu_read32(base + SIU_STFIFO);
  61         siu_write32(base + SIU_STFIFO, stfifo & ~0x0c180c18);
  62         pr_debug("%s: STFIFO %x -> %x\n", __func__,
  63                  stfifo, stfifo & ~0x0c180c18);
  64
  65         /* during stmwrite clear */
  66         siu_stream->rw_flg = 0;
  67
  68         return 0;
  69 }
  70
  71 static int siu_pcm_stmwrite_start(struct siu_port *port_info)
  72 {
  73         struct siu_stream *siu_stream = &port_info->playback;
  74
  75         if (siu_stream->rw_flg)
  76                 return -EPERM;
  77
  78         /* Current period in buffer */
  79         port_info->playback.cur_period = 0;
  80
  81         /* during stmwrite flag set */
  82         siu_stream->rw_flg = RWF_STM_WT;
  83
  84         /* DMA transfer start */
  85         tasklet_schedule(&siu_stream->tasklet);
  86
  87         return 0;
  88 }
  89
  90 static void siu_dma_tx_complete(void *arg)
  91 {
  92         struct siu_stream *siu_stream = arg;
  93
  94         if (!siu_stream->rw_flg)
  95                 return;
  96
  97         /* Update completed period count */
  98         if (++siu_stream->cur_period >=
  99             GET_MAX_PERIODS(siu_stream->buf_bytes,
 100                             siu_stream->period_bytes))
 101                 siu_stream->cur_period = 0;
 102
 103         pr_debug("%s: done period #%d (%u/%u bytes), cookie %d\n",
 104                 __func__, siu_stream->cur_period,
 105                 siu_stream->cur_period * siu_stream->period_bytes,
 106                 siu_stream->buf_bytes, siu_stream->cookie);
 107
 108         tasklet_schedule(&siu_stream->tasklet);
 109
 110         /* Notify alsa: a period is done */
 111         snd_pcm_period_elapsed(siu_stream->substream);
 112 }
 113
 114 static int siu_pcm_wr_set(struct siu_port *port_info,
 115                           dma_addr_t buff, u32 size)
 116 {
 117         struct siu_info *info = siu_i2s_dai.private_data;
 118         u32 __iomem *base = info->reg;
 119         struct siu_stream *siu_stream = &port_info->playback;
 120         struct snd_pcm_substream *substream = siu_stream->substream;
 121         struct device *dev = substream->pcm->card->dev;
 122         struct dma_async_tx_descriptor *desc;
 123         dma_cookie_t cookie;
 124         struct scatterlist sg;
 125         u32 stfifo;
 126
 127         sg_init_table(&sg, 1);
 128         sg_set_page(&sg, pfn_to_page(PFN_DOWN(buff)),
 129                     size, offset_in_page(buff));
 130         sg_dma_address(&sg) = buff;
 131
 132         desc = siu_stream->chan->device->device_prep_slave_sg(siu_stream->chan,
 133                 &sg, 1, DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 134         if (!desc) {
 135                 dev_err(dev, "Failed to allocate a dma descriptor\n");
 136                 return -ENOMEM;
 137         }
 138
 139         desc->callback = siu_dma_tx_complete;
 140         desc->callback_param = siu_stream;
 141         cookie = desc->tx_submit(desc);
 142         if (cookie < 0) {
 143                 dev_err(dev, "Failed to submit a dma transfer\n");
 144                 return cookie;
 145         }
 146
 147         siu_stream->tx_desc = desc;
 148         siu_stream->cookie = cookie;
 149
 150         dma_async_issue_pending(siu_stream->chan);
 151
 152         /* only output FIFO enable */
 153         stfifo = siu_read32(base + SIU_STFIFO);
 154         siu_write32(base + SIU_STFIFO, stfifo | (port_info->stfifo & 0x0c180c18));
 155         dev_dbg(dev, "%s: STFIFO %x -> %x\n", __func__,
 156                 stfifo, stfifo | (port_info->stfifo & 0x0c180c18));
 157
 158         return 0;
 159 }
 160
 161 static int siu_pcm_rd_set(struct siu_port *port_info,
 162                           dma_addr_t buff, size_t size)
 163 {
 164         struct siu_info *info = siu_i2s_dai.private_data;
 165         u32 __iomem *base = info->reg;
 166         struct siu_stream *siu_stream = &port_info->capture;
 167         struct snd_pcm_substream *substream = siu_stream->substream;
 168         struct device *dev = substream->pcm->card->dev;
 169         struct dma_async_tx_descriptor *desc;
 170         dma_cookie_t cookie;
 171         struct scatterlist sg;
 172         u32 stfifo;
 173
 174         dev_dbg(dev, "%s: %u@%llx\n", __func__, size, (unsigned long long)buff);
 175
 176         sg_init_table(&sg, 1);
 177         sg_set_page(&sg, pfn_to_page(PFN_DOWN(buff)),
 178                     size, offset_in_page(buff));
 179         sg_dma_address(&sg) = buff;
 180
 181         desc = siu_stream->chan->device->device_prep_slave_sg(siu_stream->chan,
 182                 &sg, 1, DMA_FROM_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 183         if (!desc) {
 184                 dev_err(dev, "Failed to allocate dma descriptor\n");
 185                 return -ENOMEM;
 186         }
 187
 188         desc->callback = siu_dma_tx_complete;
 189         desc->callback_param = siu_stream;
 190         cookie = desc->tx_submit(desc);
 191         if (cookie < 0) {
 192                 dev_err(dev, "Failed to submit dma descriptor\n");
 193                 return cookie;
 194         }
 195
 196         siu_stream->tx_desc = desc;
 197         siu_stream->cookie = cookie;
 198
 199         dma_async_issue_pending(siu_stream->chan);
 200
 201         /* only input FIFO enable */
 202         stfifo = siu_read32(base + SIU_STFIFO);
 203         siu_write32(base + SIU_STFIFO, siu_read32(base + SIU_STFIFO) |
 204                     (port_info->stfifo & 0x13071307));
 205         dev_dbg(dev, "%s: STFIFO %x -> %x\n", __func__,
 206                 stfifo, stfifo | (port_info->stfifo & 0x13071307));
 207
 208         return 0;
 209 }
 210
 211 static void siu_io_tasklet(unsigned long data)
 212 {
 213         struct siu_stream *siu_stream = (struct siu_stream *)data;
 214         struct snd_pcm_substream *substream = siu_stream->substream;
 215         struct device *dev = substream->pcm->card->dev;
 216         struct snd_pcm_runtime *rt = substream->runtime;
 217         struct siu_port *port_info = siu_port_info(substream);
 218
 219         dev_dbg(dev, "%s: flags %x\n", __func__, siu_stream->rw_flg);
 220
 221         if (!siu_stream->rw_flg) {
 222                 dev_dbg(dev, "%s: stream inactive\n", __func__);
 223                 return;
 224         }
 225
 226         if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 227                 dma_addr_t buff;
 228                 size_t count;
 229                 u8 *virt;
 230
 231                 buff = (dma_addr_t)PERIOD_OFFSET(rt->dma_addr,
 232                                                 siu_stream->cur_period,
 233                                                 siu_stream->period_bytes);
 234                 virt = PERIOD_OFFSET(rt->dma_area,
 235                                      siu_stream->cur_period,
 236                                      siu_stream->period_bytes);
 237                 count = siu_stream->period_bytes;
 238
 239                 /* DMA transfer start */
 240                 siu_pcm_rd_set(port_info, buff, count);
 241         } else {
 242                 siu_pcm_wr_set(port_info,
 243                                (dma_addr_t)PERIOD_OFFSET(rt->dma_addr,
 244                                                 siu_stream->cur_period,
 245                                                 siu_stream->period_bytes),
 246                                siu_stream->period_bytes);
 247         }
 248 }
 249
 250 /* Capture */
 251 static int siu_pcm_stmread_start(struct siu_port *port_info)
 252 {
 253         struct siu_stream *siu_stream = &port_info->capture;
 254
 255         if (siu_stream->xfer_cnt > 0x1000000)
 256                 return -EINVAL;
 257         if (siu_stream->rw_flg)
 258                 return -EPERM;
 259
 260         /* Current period in buffer */
 261         siu_stream->cur_period = 0;
 262
 263         /* during stmread flag set */
 264         siu_stream->rw_flg = RWF_STM_RD;
 265
 266         tasklet_schedule(&siu_stream->tasklet);
 267
 268         return 0;
 269 }
 270
 271 static int siu_pcm_stmread_stop(struct siu_port *port_info)
 272 {
 273         struct siu_info *info = siu_i2s_dai.private_data;
 274         u32 __iomem *base = info->reg;
 275         struct siu_stream *siu_stream = &port_info->capture;
 276         struct device *dev = siu_stream->substream->pcm->card->dev;
 277         u32 stfifo;
 278
 279         if (!siu_stream->rw_flg)
 280                 return -EPERM;
 281
 282         /* input FIFO disable */
 283         stfifo = siu_read32(base + SIU_STFIFO);
 284         siu_write32(base + SIU_STFIFO, stfifo & ~0x13071307);
 285         dev_dbg(dev, "%s: STFIFO %x -> %x\n", __func__,
 286                 stfifo, stfifo & ~0x13071307);
 287
 288         /* during stmread flag clear */
 289         siu_stream->rw_flg = 0;
 290
 291         return 0;
 292 }
 293
 294 static int siu_pcm_hw_params(struct snd_pcm_substream *ss,
 295                              struct snd_pcm_hw_params *hw_params)
 296 {
 297         struct siu_info *info = siu_i2s_dai.private_data;
 298         struct device *dev = ss->pcm->card->dev;
 299         int ret;
 300
 301         dev_dbg(dev, "%s: port=%d\n", __func__, info->port_id);
 302
 303         ret = snd_pcm_lib_malloc_pages(ss, params_buffer_bytes(hw_params));
 304         if (ret < 0)
 305                 dev_err(dev, "snd_pcm_lib_malloc_pages() failed\n");
 306
 307         return ret;
 308 }
 309
 310 static int siu_pcm_hw_free(struct snd_pcm_substream *ss)
 311 {
 312         struct siu_info *info = siu_i2s_dai.private_data;
 313         struct siu_port *port_info = siu_port_info(ss);
 314         struct device *dev = ss->pcm->card->dev;
 315         struct siu_stream *siu_stream;
 316
 317         if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
 318                 siu_stream = &port_info->playback;
 319         else
 320                 siu_stream = &port_info->capture;
 321
 322         dev_dbg(dev, "%s: port=%d\n", __func__, info->port_id);
 323
 324         return snd_pcm_lib_free_pages(ss);
 325 }
 326
 327 static bool filter(struct dma_chan *chan, void *slave)
 328 {
 329         struct sh_dmae_slave *param = slave;
 330
 331         pr_debug("%s: slave ID %d\n", __func__, param->slave_id);
 332
 333         if (unlikely(param->dma_dev != chan->device->dev))
 334                 return false;
 335
 336         chan->private = param;
 337         return true;
 338 }
 339
 340 static int siu_pcm_open(struct snd_pcm_substream *ss)
 341 {
 342         /* Playback / Capture */
 343         struct siu_info *info = siu_i2s_dai.private_data;
 344         struct siu_port *port_info = siu_port_info(ss);
 345         struct siu_stream *siu_stream;
 346         u32 port = info->port_id;
 347         struct siu_platform *pdata = siu_i2s_dai.dev->platform_data;
 348         struct device *dev = ss->pcm->card->dev;
 349         dma_cap_mask_t mask;
 350         struct sh_dmae_slave *param;
 351
 352         dma_cap_zero(mask);
 353         dma_cap_set(DMA_SLAVE, mask);
 354
 355         dev_dbg(dev, "%s, port=%d@%p\n", __func__, port, port_info);
 356
 357         if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 358                 siu_stream = &port_info->playback;
 359                 param = &siu_stream->param;
 360                 param->slave_id = port ? pdata->dma_slave_tx_b :
 361                         pdata->dma_slave_tx_a;
 362         } else {
 363                 siu_stream = &port_info->capture;
 364                 param = &siu_stream->param;
 365                 param->slave_id = port ? pdata->dma_slave_rx_b :
 366                         pdata->dma_slave_rx_a;
 367         }
 368
 369         param->dma_dev = pdata->dma_dev;
 370         /* Get DMA channel */
 371         siu_stream->chan = dma_request_channel(mask, filter, param);
 372         if (!siu_stream->chan) {
 373                 dev_err(dev, "DMA channel allocation failed!\n");
 374                 return -EBUSY;
 375         }
 376
 377         siu_stream->substream = ss;
 378
 379         return 0;
 380 }
 381
 382 static int siu_pcm_close(struct snd_pcm_substream *ss)
 383 {
 384         struct siu_info *info = siu_i2s_dai.private_data;
 385         struct device *dev = ss->pcm->card->dev;
 386         struct siu_port *port_info = siu_port_info(ss);
 387         struct siu_stream *siu_stream;
 388
 389         dev_dbg(dev, "%s: port=%d\n", __func__, info->port_id);
 390
 391         if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
 392                 siu_stream = &port_info->playback;
 393         else
 394                 siu_stream = &port_info->capture;
 395
 396         dma_release_channel(siu_stream->chan);
 397         siu_stream->chan = NULL;
 398
 399         siu_stream->substream = NULL;
 400
 401         return 0;
 402 }
 403
 404 static int siu_pcm_prepare(struct snd_pcm_substream *ss)
 405 {
 406         struct siu_info *info = siu_i2s_dai.private_data;
 407         struct siu_port *port_info = siu_port_info(ss);
 408         struct device *dev = ss->pcm->card->dev;
 409         struct snd_pcm_runtime  *rt = ss->runtime;
 410         struct siu_stream *siu_stream;
 411         snd_pcm_sframes_t xfer_cnt;
 412
 413         if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
 414                 siu_stream = &port_info->playback;
 415         else
 416                 siu_stream = &port_info->capture;
 417
 418         rt = siu_stream->substream->runtime;
 419
 420         siu_stream->buf_bytes = snd_pcm_lib_buffer_bytes(ss);
 421         siu_stream->period_bytes = snd_pcm_lib_period_bytes(ss);
 422
 423         dev_dbg(dev, "%s: port=%d, %d channels, period=%u bytes\n", __func__,
 424                 info->port_id, rt->channels, siu_stream->period_bytes);
 425
 426         /* We only support buffers that are multiples of the period */
 427         if (siu_stream->buf_bytes % siu_stream->period_bytes) {
 428                 dev_err(dev, "%s() - buffer=%d not multiple of period=%d\n",
 429                        __func__, siu_stream->buf_bytes,
 430                        siu_stream->period_bytes);
 431                 return -EINVAL;
 432         }
 433
 434         xfer_cnt = bytes_to_frames(rt, siu_stream->period_bytes);
 435         if (!xfer_cnt || xfer_cnt > 0x1000000)
 436                 return -EINVAL;
 437
 438         siu_stream->format = rt->format;
 439         siu_stream->xfer_cnt = xfer_cnt;
 440
 441         dev_dbg(dev, "port=%d buf=%lx buf_bytes=%d period_bytes=%d "
 442                 "format=%d channels=%d xfer_cnt=%d\n", info->port_id,
 443                 (unsigned long)rt->dma_addr, siu_stream->buf_bytes,
 444                 siu_stream->period_bytes,
 445                 siu_stream->format, rt->channels, (int)xfer_cnt);
 446
 447         return 0;
 448 }
 449
 450 static int siu_pcm_trigger(struct snd_pcm_substream *ss, int cmd)
 451 {
 452         struct siu_info *info = siu_i2s_dai.private_data;
 453         struct device *dev = ss->pcm->card->dev;
 454         struct siu_port *port_info = siu_port_info(ss);
 455         int ret;
 456
 457         dev_dbg(dev, "%s: port=%d@%p, cmd=%d\n", __func__,
 458                 info->port_id, port_info, cmd);
 459
 460         switch (cmd) {
 461         case SNDRV_PCM_TRIGGER_START:
 462                 if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
 463                         ret = siu_pcm_stmwrite_start(port_info);
 464                 else
 465                         ret = siu_pcm_stmread_start(port_info);
 466
 467                 if (ret < 0)
 468                         dev_warn(dev, "%s: start failed on port=%d\n",
 469                                  __func__, info->port_id);
 470
 471                 break;
 472         case SNDRV_PCM_TRIGGER_STOP:
 473                 if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
 474                         siu_pcm_stmwrite_stop(port_info);
 475                 else
 476                         siu_pcm_stmread_stop(port_info);
 477                 ret = 0;
 478
 479                 break;
 480         default:
 481                 dev_err(dev, "%s() unsupported cmd=%d\n", __func__, cmd);
 482                 ret = -EINVAL;
 483         }
 484
 485         return ret;
 486 }
 487
 488 /*
 489  * So far only resolution of one period is supported, subject to extending the
 490  * dmangine API
 491  */
 492 static snd_pcm_uframes_t siu_pcm_pointer_dma(struct snd_pcm_substream *ss)
 493 {
 494         struct device *dev = ss->pcm->card->dev;
 495         struct siu_info *info = siu_i2s_dai.private_data;
 496         u32 __iomem *base = info->reg;
 497         struct siu_port *port_info = siu_port_info(ss);
 498         struct snd_pcm_runtime *rt = ss->runtime;
 499         size_t ptr;
 500         struct siu_stream *siu_stream;
 501
 502         if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
 503                 siu_stream = &port_info->playback;
 504         else
 505                 siu_stream = &port_info->capture;
 506
 507         /*
 508          * ptr is the offset into the buffer where the dma is currently at. We
 509          * check if the dma buffer has just wrapped.
 510          */
 511         ptr = PERIOD_OFFSET(rt->dma_addr,
 512                             siu_stream->cur_period,
 513                             siu_stream->period_bytes) - rt->dma_addr;
 514
 515         dev_dbg(dev,
 516                 "%s: port=%d, events %x, FSTS %x, xferred %u/%u, cookie %d\n",
 517                 __func__, info->port_id, siu_read32(base + SIU_EVNTC),
 518                 siu_read32(base + SIU_SBFSTS), ptr, siu_stream->buf_bytes,
 519                 siu_stream->cookie);
 520
 521         if (ptr >= siu_stream->buf_bytes)
 522                 ptr = 0;
 523
 524         return bytes_to_frames(ss->runtime, ptr);
 525 }
 526
 527 static int siu_pcm_new(struct snd_card *card, struct snd_soc_dai *dai,
 528                        struct snd_pcm *pcm)
 529 {
 530         /* card->dev == socdev->dev, see snd_soc_new_pcms() */
 531         struct siu_info *info = siu_i2s_dai.private_data;
 532         struct platform_device *pdev = to_platform_device(card->dev);
 533         int ret;
 534         int i;
 535
 536         /* pdev->id selects between SIUA and SIUB */
 537         if (pdev->id < 0 || pdev->id >= SIU_PORT_NUM)
 538                 return -EINVAL;
 539
 540         info->port_id = pdev->id;
 541
 542         /*
 543          * While the siu has 2 ports, only one port can be on at a time (only 1
 544          * SPB). So far all the boards using the siu had only one of the ports
 545          * wired to a codec. To simplify things, we only register one port with
 546          * alsa. In case both ports are needed, it should be changed here
 547          */
 548         for (i = pdev->id; i < pdev->id + 1; i++) {
 549                 struct siu_port **port_info = &siu_ports[i];
 550
 551                 ret = siu_init_port(i, port_info, card);
 552                 if (ret < 0)
 553                         return ret;
 554
 555                 ret = snd_pcm_lib_preallocate_pages_for_all(pcm,
 556                                 SNDRV_DMA_TYPE_DEV, NULL,
 557                                 SIU_BUFFER_BYTES_MAX, SIU_BUFFER_BYTES_MAX);
 558                 if (ret < 0) {
 559                         dev_err(card->dev,
 560                                "snd_pcm_lib_preallocate_pages_for_all() err=%d",
 561                                 ret);
 562                         goto fail;
 563                 }
 564
 565                 (*port_info)->pcm = pcm;
 566
 567                 /* IO tasklets */
 568                 tasklet_init(&(*port_info)->playback.tasklet, siu_io_tasklet,
 569                              (unsigned long)&(*port_info)->playback);
 570                 tasklet_init(&(*port_info)->capture.tasklet, siu_io_tasklet,
 571                              (unsigned long)&(*port_info)->capture);
 572         }
 573
 574         dev_info(card->dev, "SuperH SIU driver initialized.\n");
 575         return 0;
 576
 577 fail:
 578         siu_free_port(siu_ports[pdev->id]);
 579         dev_err(card->dev, "SIU: failed to initialize.\n");
 580         return ret;
 581 }
 582
 583 static void siu_pcm_free(struct snd_pcm *pcm)
 584 {
 585         struct platform_device *pdev = to_platform_device(pcm->card->dev);
 586         struct siu_port *port_info = siu_ports[pdev->id];
 587
 588         tasklet_kill(&port_info->capture.tasklet);
 589         tasklet_kill(&port_info->playback.tasklet);
 590
 591         siu_free_port(port_info);
 592         snd_pcm_lib_preallocate_free_for_all(pcm);
 593
 594         dev_dbg(pcm->card->dev, "%s\n", __func__);
 595 }
 596
 597 static struct snd_pcm_ops siu_pcm_ops = {
 598         .open           = siu_pcm_open,
 599         .close          = siu_pcm_close,
 600         .ioctl          = snd_pcm_lib_ioctl,
 601         .hw_params      = siu_pcm_hw_params,
 602         .hw_free        = siu_pcm_hw_free,
 603         .prepare        = siu_pcm_prepare,
 604         .trigger        = siu_pcm_trigger,
 605         .pointer        = siu_pcm_pointer_dma,
 606 };
 607
 608 struct snd_soc_platform siu_platform = {
 609         .name           = "siu-audio",
 610         .pcm_ops        = &siu_pcm_ops,
 611         .pcm_new        = siu_pcm_new,
 612         .pcm_free       = siu_pcm_free,
 613 };
 614 EXPORT_SYMBOL_GPL(siu_platform);