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![Jose Abreu](/assets/img/avatar_default.png)
A PCM extension was added to I2S driver so that audio samples are transferred using PIO mode. The PCM supports two channels @ 16 or 32 bits with rates 32k, 44.1k and 48k. Although the mainline I2S driver uses ALSA DMA engine the I2S controller can be built without DMA support, therefore this is the reason why this extension was added. Signed-off-by: Jose Abreu <joabreu@synopsys.com> Cc: Carlos Palminha <palminha@synopsys.com> Cc: Mark Brown <broonie@kernel.org> Cc: Liam Girdwood <lgirdwood@gmail.com> Cc: Jaroslav Kysela <perex@perex.cz> Cc: Takashi Iwai <tiwai@suse.com> Cc: Rob Herring <robh@kernel.org> Cc: Alexey Brodkin <abrodkin@synopsys.com> Cc: linux-snps-arc@lists.infradead.org Cc: alsa-devel@alsa-project.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Mark Brown <broonie@kernel.org>
225 lines
5.6 KiB
C
225 lines
5.6 KiB
C
/*
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* ALSA SoC Synopsys PIO PCM for I2S driver
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*
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* sound/soc/dwc/designware_pcm.c
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*
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* Copyright (C) 2016 Synopsys
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* Jose Abreu <joabreu@synopsys.com>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/io.h>
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#include <linux/rcupdate.h>
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#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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#include "local.h"
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#define BUFFER_BYTES_MAX (3 * 2 * 8 * PERIOD_BYTES_MIN)
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#define PERIOD_BYTES_MIN 4096
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#define PERIODS_MIN 2
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#define dw_pcm_tx_fn(sample_bits) \
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static unsigned int dw_pcm_tx_##sample_bits(struct dw_i2s_dev *dev, \
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struct snd_pcm_runtime *runtime, unsigned int tx_ptr, \
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bool *period_elapsed) \
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{ \
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const u##sample_bits (*p)[2] = (void *)runtime->dma_area; \
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unsigned int period_pos = tx_ptr % runtime->period_size; \
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int i; \
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\
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for (i = 0; i < dev->fifo_th; i++) { \
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iowrite32(p[tx_ptr][0], dev->i2s_base + LRBR_LTHR(0)); \
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iowrite32(p[tx_ptr][1], dev->i2s_base + RRBR_RTHR(0)); \
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period_pos++; \
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if (++tx_ptr >= runtime->buffer_size) \
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tx_ptr = 0; \
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} \
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*period_elapsed = period_pos >= runtime->period_size; \
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return tx_ptr; \
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}
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dw_pcm_tx_fn(16);
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dw_pcm_tx_fn(32);
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#undef dw_pcm_tx_fn
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static const struct snd_pcm_hardware dw_pcm_hardware = {
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.info = SNDRV_PCM_INFO_INTERLEAVED |
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SNDRV_PCM_INFO_MMAP |
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SNDRV_PCM_INFO_MMAP_VALID |
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SNDRV_PCM_INFO_BLOCK_TRANSFER,
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.rates = SNDRV_PCM_RATE_32000 |
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SNDRV_PCM_RATE_44100 |
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SNDRV_PCM_RATE_48000,
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.rate_min = 32000,
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.rate_max = 48000,
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.formats = SNDRV_PCM_FMTBIT_S16_LE |
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SNDRV_PCM_FMTBIT_S32_LE,
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.channels_min = 2,
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.channels_max = 2,
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.buffer_bytes_max = BUFFER_BYTES_MAX,
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.period_bytes_min = PERIOD_BYTES_MIN,
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.period_bytes_max = BUFFER_BYTES_MAX / PERIODS_MIN,
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.periods_min = PERIODS_MIN,
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.periods_max = BUFFER_BYTES_MAX / PERIOD_BYTES_MIN,
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.fifo_size = 16,
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};
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void dw_pcm_push_tx(struct dw_i2s_dev *dev)
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{
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struct snd_pcm_substream *tx_substream;
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bool tx_active, period_elapsed;
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rcu_read_lock();
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tx_substream = rcu_dereference(dev->tx_substream);
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tx_active = tx_substream && snd_pcm_running(tx_substream);
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if (tx_active) {
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unsigned int tx_ptr = READ_ONCE(dev->tx_ptr);
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unsigned int new_tx_ptr = dev->tx_fn(dev, tx_substream->runtime,
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tx_ptr, &period_elapsed);
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cmpxchg(&dev->tx_ptr, tx_ptr, new_tx_ptr);
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if (period_elapsed)
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snd_pcm_period_elapsed(tx_substream);
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}
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rcu_read_unlock();
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}
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EXPORT_SYMBOL_GPL(dw_pcm_push_tx);
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static int dw_pcm_open(struct snd_pcm_substream *substream)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct snd_soc_pcm_runtime *rtd = substream->private_data;
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struct dw_i2s_dev *dev = snd_soc_dai_get_drvdata(rtd->cpu_dai);
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snd_soc_set_runtime_hwparams(substream, &dw_pcm_hardware);
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snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
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runtime->private_data = dev;
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return 0;
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}
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static int dw_pcm_close(struct snd_pcm_substream *substream)
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{
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synchronize_rcu();
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return 0;
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}
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static int dw_pcm_hw_params(struct snd_pcm_substream *substream,
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struct snd_pcm_hw_params *hw_params)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct dw_i2s_dev *dev = runtime->private_data;
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int ret;
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switch (params_channels(hw_params)) {
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case 2:
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break;
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default:
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dev_err(dev->dev, "invalid channels number\n");
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return -EINVAL;
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}
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switch (params_format(hw_params)) {
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case SNDRV_PCM_FORMAT_S16_LE:
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dev->tx_fn = dw_pcm_tx_16;
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break;
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case SNDRV_PCM_FORMAT_S32_LE:
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dev->tx_fn = dw_pcm_tx_32;
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break;
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default:
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dev_err(dev->dev, "invalid format\n");
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return -EINVAL;
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}
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if (substream->stream != SNDRV_PCM_STREAM_PLAYBACK) {
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dev_err(dev->dev, "only playback is available\n");
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return -EINVAL;
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}
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ret = snd_pcm_lib_malloc_pages(substream,
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params_buffer_bytes(hw_params));
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if (ret < 0)
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return ret;
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else
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return 0;
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}
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static int dw_pcm_hw_free(struct snd_pcm_substream *substream)
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{
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return snd_pcm_lib_free_pages(substream);
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}
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static int dw_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct dw_i2s_dev *dev = runtime->private_data;
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int ret = 0;
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switch (cmd) {
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case SNDRV_PCM_TRIGGER_START:
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case SNDRV_PCM_TRIGGER_RESUME:
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case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
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WRITE_ONCE(dev->tx_ptr, 0);
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rcu_assign_pointer(dev->tx_substream, substream);
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break;
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case SNDRV_PCM_TRIGGER_STOP:
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case SNDRV_PCM_TRIGGER_SUSPEND:
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case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
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rcu_assign_pointer(dev->tx_substream, NULL);
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break;
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default:
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ret = -EINVAL;
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break;
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}
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return ret;
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}
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static snd_pcm_uframes_t dw_pcm_pointer(struct snd_pcm_substream *substream)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct dw_i2s_dev *dev = runtime->private_data;
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snd_pcm_uframes_t pos = READ_ONCE(dev->tx_ptr);
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return pos < runtime->buffer_size ? pos : 0;
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}
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static int dw_pcm_new(struct snd_soc_pcm_runtime *rtd)
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{
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size_t size = dw_pcm_hardware.buffer_bytes_max;
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return snd_pcm_lib_preallocate_pages_for_all(rtd->pcm,
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SNDRV_DMA_TYPE_CONTINUOUS,
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snd_dma_continuous_data(GFP_KERNEL), size, size);
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}
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static void dw_pcm_free(struct snd_pcm *pcm)
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{
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snd_pcm_lib_preallocate_free_for_all(pcm);
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}
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static const struct snd_pcm_ops dw_pcm_ops = {
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.open = dw_pcm_open,
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.close = dw_pcm_close,
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.ioctl = snd_pcm_lib_ioctl,
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.hw_params = dw_pcm_hw_params,
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.hw_free = dw_pcm_hw_free,
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.trigger = dw_pcm_trigger,
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.pointer = dw_pcm_pointer,
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};
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static const struct snd_soc_platform_driver dw_pcm_platform = {
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.pcm_new = dw_pcm_new,
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.pcm_free = dw_pcm_free,
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.ops = &dw_pcm_ops,
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};
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int dw_pcm_register(struct platform_device *pdev)
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{
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return devm_snd_soc_register_platform(&pdev->dev, &dw_pcm_platform);
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}
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EXPORT_SYMBOL_GPL(dw_pcm_register);
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