linux/sound/soc/soc-dmaengine-pcm.c
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   1/*
   2 *  Copyright (C) 2012, Analog Devices Inc.
   3 *      Author: Lars-Peter Clausen <lars@metafoo.de>
   4 *
   5 *  Based on:
   6 *      imx-pcm-dma-mx2.c, Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
   7 *      mxs-pcm.c, Copyright (C) 2011 Freescale Semiconductor, Inc.
   8 *      ep93xx-pcm.c, Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
   9 *                    Copyright (C) 2006 Applied Data Systems
  10 *
  11 *  This program is free software; you can redistribute it and/or modify it
  12 *  under  the terms of the GNU General  Public License as published by the
  13 *  Free Software Foundation;  either version 2 of the License, or (at your
  14 *  option) any later version.
  15 *
  16 *  You should have received a copy of the GNU General Public License along
  17 *  with this program; if not, write to the Free Software Foundation, Inc.,
  18 *  675 Mass Ave, Cambridge, MA 02139, USA.
  19 *
  20 */
  21#include <linux/module.h>
  22#include <linux/init.h>
  23#include <linux/dmaengine.h>
  24#include <linux/slab.h>
  25#include <sound/pcm.h>
  26#include <sound/pcm_params.h>
  27#include <sound/soc.h>
  28
  29#include <sound/dmaengine_pcm.h>
  30
  31struct dmaengine_pcm_runtime_data {
  32        struct dma_chan *dma_chan;
  33        dma_cookie_t cookie;
  34
  35        unsigned int pos;
  36
  37        void *data;
  38};
  39
  40static inline struct dmaengine_pcm_runtime_data *substream_to_prtd(
  41        const struct snd_pcm_substream *substream)
  42{
  43        return substream->runtime->private_data;
  44}
  45
  46/**
  47 * snd_dmaengine_pcm_set_data - Set dmaengine substream private data
  48 * @substream: PCM substream
  49 * @data: Data to set
  50 */
  51void snd_dmaengine_pcm_set_data(struct snd_pcm_substream *substream, void *data)
  52{
  53        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
  54
  55        prtd->data = data;
  56}
  57EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_data);
  58
  59/**
  60 * snd_dmaengine_pcm_get_data - Get dmaeinge substream private data
  61 * @substream: PCM substream
  62 *
  63 * Returns the data previously set with snd_dmaengine_pcm_set_data
  64 */
  65void *snd_dmaengine_pcm_get_data(struct snd_pcm_substream *substream)
  66{
  67        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
  68
  69        return prtd->data;
  70}
  71EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_data);
  72
  73struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream)
  74{
  75        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
  76
  77        return prtd->dma_chan;
  78}
  79EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_chan);
  80
  81/**
  82 * snd_hwparams_to_dma_slave_config - Convert hw_params to dma_slave_config
  83 * @substream: PCM substream
  84 * @params: hw_params
  85 * @slave_config: DMA slave config
  86 *
  87 * This function can be used to initialize a dma_slave_config from a substream
  88 * and hw_params in a dmaengine based PCM driver implementation.
  89 */
  90int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
  91        const struct snd_pcm_hw_params *params,
  92        struct dma_slave_config *slave_config)
  93{
  94        enum dma_slave_buswidth buswidth;
  95
  96        switch (params_format(params)) {
  97        case SNDRV_PCM_FORMAT_S8:
  98                buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
  99                break;
 100        case SNDRV_PCM_FORMAT_S16_LE:
 101                buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
 102                break;
 103        case SNDRV_PCM_FORMAT_S18_3LE:
 104        case SNDRV_PCM_FORMAT_S20_3LE:
 105        case SNDRV_PCM_FORMAT_S24_LE:
 106        case SNDRV_PCM_FORMAT_S32_LE:
 107                buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
 108                break;
 109        default:
 110                return -EINVAL;
 111        }
 112
 113        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 114                slave_config->direction = DMA_MEM_TO_DEV;
 115                slave_config->dst_addr_width = buswidth;
 116        } else {
 117                slave_config->direction = DMA_DEV_TO_MEM;
 118                slave_config->src_addr_width = buswidth;
 119        }
 120
 121        return 0;
 122}
 123EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);
 124
 125static void dmaengine_pcm_dma_complete(void *arg)
 126{
 127        struct snd_pcm_substream *substream = arg;
 128        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 129
 130        prtd->pos += snd_pcm_lib_period_bytes(substream);
 131        if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream))
 132                prtd->pos = 0;
 133
 134        snd_pcm_period_elapsed(substream);
 135}
 136
 137static int dmaengine_pcm_prepare_and_submit(struct snd_pcm_substream *substream)
 138{
 139        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 140        struct dma_chan *chan = prtd->dma_chan;
 141        struct dma_async_tx_descriptor *desc;
 142        enum dma_transfer_direction direction;
 143
 144        direction = snd_pcm_substream_to_dma_direction(substream);
 145
 146        prtd->pos = 0;
 147        desc = dmaengine_prep_dma_cyclic(chan,
 148                substream->runtime->dma_addr,
 149                snd_pcm_lib_buffer_bytes(substream),
 150                snd_pcm_lib_period_bytes(substream), direction);
 151
 152        if (!desc)
 153                return -ENOMEM;
 154
 155        desc->callback = dmaengine_pcm_dma_complete;
 156        desc->callback_param = substream;
 157        prtd->cookie = dmaengine_submit(desc);
 158
 159        return 0;
 160}
 161
 162/**
 163 * snd_dmaengine_pcm_trigger - dmaengine based PCM trigger implementation
 164 * @substream: PCM substream
 165 * @cmd: Trigger command
 166 *
 167 * Returns 0 on success, a negative error code otherwise.
 168 *
 169 * This function can be used as the PCM trigger callback for dmaengine based PCM
 170 * driver implementations.
 171 */
 172int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 173{
 174        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 175        int ret;
 176
 177        switch (cmd) {
 178        case SNDRV_PCM_TRIGGER_START:
 179                ret = dmaengine_pcm_prepare_and_submit(substream);
 180                if (ret)
 181                        return ret;
 182                dma_async_issue_pending(prtd->dma_chan);
 183                break;
 184        case SNDRV_PCM_TRIGGER_RESUME:
 185        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 186                dmaengine_resume(prtd->dma_chan);
 187                break;
 188        case SNDRV_PCM_TRIGGER_SUSPEND:
 189        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 190                dmaengine_pause(prtd->dma_chan);
 191                break;
 192        case SNDRV_PCM_TRIGGER_STOP:
 193                dmaengine_terminate_all(prtd->dma_chan);
 194                break;
 195        default:
 196                return -EINVAL;
 197        }
 198
 199        return 0;
 200}
 201EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_trigger);
 202
 203/**
 204 * snd_dmaengine_pcm_pointer_no_residue - dmaengine based PCM pointer implementation
 205 * @substream: PCM substream
 206 *
 207 * This function is deprecated and should not be used by new drivers, as its
 208 * results may be unreliable.
 209 */
 210snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream *substream)
 211{
 212        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 213        return bytes_to_frames(substream->runtime, prtd->pos);
 214}
 215EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer_no_residue);
 216
 217/**
 218 * snd_dmaengine_pcm_pointer - dmaengine based PCM pointer implementation
 219 * @substream: PCM substream
 220 *
 221 * This function can be used as the PCM pointer callback for dmaengine based PCM
 222 * driver implementations.
 223 */
 224snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
 225{
 226        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 227        struct dma_tx_state state;
 228        enum dma_status status;
 229        unsigned int buf_size;
 230        unsigned int pos = 0;
 231
 232        status = dmaengine_tx_status(prtd->dma_chan, prtd->cookie, &state);
 233        if (status == DMA_IN_PROGRESS || status == DMA_PAUSED) {
 234                buf_size = snd_pcm_lib_buffer_bytes(substream);
 235                if (state.residue > 0 && state.residue <= buf_size)
 236                        pos = buf_size - state.residue;
 237        }
 238
 239        return bytes_to_frames(substream->runtime, pos);
 240}
 241EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);
 242
 243static int dmaengine_pcm_request_channel(struct dmaengine_pcm_runtime_data *prtd,
 244        dma_filter_fn filter_fn, void *filter_data)
 245{
 246        dma_cap_mask_t mask;
 247
 248        dma_cap_zero(mask);
 249        dma_cap_set(DMA_SLAVE, mask);
 250        dma_cap_set(DMA_CYCLIC, mask);
 251        prtd->dma_chan = dma_request_channel(mask, filter_fn, filter_data);
 252
 253        if (!prtd->dma_chan)
 254                return -ENXIO;
 255
 256        return 0;
 257}
 258
 259/**
 260 * snd_dmaengine_pcm_open - Open a dmaengine based PCM substream
 261 * @substream: PCM substream
 262 * @filter_fn: Filter function used to request the DMA channel
 263 * @filter_data: Data passed to the DMA filter function
 264 *
 265 * Returns 0 on success, a negative error code otherwise.
 266 *
 267 * This function will request a DMA channel using the passed filter function and
 268 * data. The function should usually be called from the pcm open callback.
 269 *
 270 * Note that this function will use private_data field of the substream's
 271 * runtime. So it is not availabe to your pcm driver implementation. If you need
 272 * to keep additional data attached to a substream use
 273 * snd_dmaengine_pcm_{set,get}_data.
 274 */
 275int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
 276        dma_filter_fn filter_fn, void *filter_data)
 277{
 278        struct dmaengine_pcm_runtime_data *prtd;
 279        int ret;
 280
 281        ret = snd_pcm_hw_constraint_integer(substream->runtime,
 282                                            SNDRV_PCM_HW_PARAM_PERIODS);
 283        if (ret < 0)
 284                return ret;
 285
 286        prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
 287        if (!prtd)
 288                return -ENOMEM;
 289
 290        ret = dmaengine_pcm_request_channel(prtd, filter_fn, filter_data);
 291        if (ret < 0) {
 292                kfree(prtd);
 293                return ret;
 294        }
 295
 296        substream->runtime->private_data = prtd;
 297
 298        return 0;
 299}
 300EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);
 301
 302/**
 303 * snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
 304 * @substream: PCM substream
 305 */
 306int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
 307{
 308        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 309
 310        dma_release_channel(prtd->dma_chan);
 311        kfree(prtd);
 312
 313        return 0;
 314}
 315EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close);
 316
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