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// SPDX-License-Identifier: GPL-2.0-only
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* Au12x0/Au1550 PSC ALSA ASoC audio support.
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* (c) 2007-2008 MSC Vertriebsges.m.b.H.,
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* Manuel Lauss <manuel.lauss@gmail.com>
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* DMA glue for Au1x-PSC audio.
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/dma-mapping.h>
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#include <sound/core.h>
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#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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#include <sound/soc.h>
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#include <asm/mach-au1x00/au1000.h>
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#include <asm/mach-au1x00/au1xxx_dbdma.h>
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#include <asm/mach-au1x00/au1xxx_psc.h>
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#define DRV_NAME "dbdma2"
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#define MSG(x...) printk(KERN_INFO "au1xpsc_pcm: " x)
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#define DBG(x...) do {} while (0)
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struct au1xpsc_audio_dmadata {
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/* DDMA control data */
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unsigned int ddma_id; /* DDMA direction ID for this PSC */
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u32 ddma_chan; /* DDMA context */
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/* PCM context (for irq handlers) */
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struct snd_pcm_substream *substream;
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unsigned long curr_period; /* current segment DDMA is working on */
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unsigned long q_period; /* queue period(s) */
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dma_addr_t dma_area; /* address of queued DMA area */
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dma_addr_t dma_area_s; /* start address of DMA area */
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unsigned long pos; /* current byte position being played */
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unsigned long periods; /* number of SG segments in total */
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unsigned long period_bytes; /* size in bytes of one SG segment */
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* These settings are somewhat okay, at least on my machine audio plays
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* almost skip-free. Especially the 64kB buffer seems to help a LOT.
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#define AU1XPSC_PERIOD_MIN_BYTES 1024
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#define AU1XPSC_BUFFER_MIN_BYTES 65536
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/* PCM hardware DMA capabilities - platform specific */
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static const struct snd_pcm_hardware au1xpsc_pcm_hardware = {
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.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
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SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BATCH,
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.period_bytes_min = AU1XPSC_PERIOD_MIN_BYTES,
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.period_bytes_max = 4096 * 1024 - 1,
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.periods_max = 4096, /* 2 to as-much-as-you-like */
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.buffer_bytes_max = 4096 * 1024 - 1,
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.fifo_size = 16, /* fifo entries of AC97/I2S PSC */
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static void au1x_pcm_queue_tx(struct au1xpsc_audio_dmadata *cd)
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au1xxx_dbdma_put_source(cd->ddma_chan, cd->dma_area,
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cd->period_bytes, DDMA_FLAGS_IE);
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/* update next-to-queue period */
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cd->dma_area += cd->period_bytes;
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if (cd->q_period >= cd->periods) {
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cd->dma_area = cd->dma_area_s;
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static void au1x_pcm_queue_rx(struct au1xpsc_audio_dmadata *cd)
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au1xxx_dbdma_put_dest(cd->ddma_chan, cd->dma_area,
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cd->period_bytes, DDMA_FLAGS_IE);
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/* update next-to-queue period */
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cd->dma_area += cd->period_bytes;
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if (cd->q_period >= cd->periods) {
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cd->dma_area = cd->dma_area_s;
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static void au1x_pcm_dmatx_cb(int irq, void *dev_id)
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struct au1xpsc_audio_dmadata *cd = dev_id;
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cd->pos += cd->period_bytes;
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if (++cd->curr_period >= cd->periods) {
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snd_pcm_period_elapsed(cd->substream);
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au1x_pcm_queue_tx(cd);
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static void au1x_pcm_dmarx_cb(int irq, void *dev_id)
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struct au1xpsc_audio_dmadata *cd = dev_id;
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cd->pos += cd->period_bytes;
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if (++cd->curr_period >= cd->periods) {
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snd_pcm_period_elapsed(cd->substream);
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au1x_pcm_queue_rx(cd);
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static void au1x_pcm_dbdma_free(struct au1xpsc_audio_dmadata *pcd)
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if (pcd->ddma_chan) {
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au1xxx_dbdma_stop(pcd->ddma_chan);
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au1xxx_dbdma_reset(pcd->ddma_chan);
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au1xxx_dbdma_chan_free(pcd->ddma_chan);
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/* in case of missing DMA ring or changed TX-source / RX-dest bit widths,
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* allocate (or reallocate) a 2-descriptor DMA ring with bit depth according
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* to ALSA-supplied sample depth. This is due to limitations in the dbdma api
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* (cannot adjust source/dest widths of already allocated descriptor ring).
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static int au1x_pcm_dbdma_realloc(struct au1xpsc_audio_dmadata *pcd,
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int stype, int msbits)
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/* DMA only in 8/16/32 bit widths */
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/* check current config: correct bits and descriptors allocated? */
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if ((pcd->ddma_chan) && (msbits == pcd->msbits))
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goto out; /* all ok! */
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au1x_pcm_dbdma_free(pcd);
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if (stype == SNDRV_PCM_STREAM_CAPTURE)
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pcd->ddma_chan = au1xxx_dbdma_chan_alloc(pcd->ddma_id,
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au1x_pcm_dmarx_cb, (void *)pcd);
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pcd->ddma_chan = au1xxx_dbdma_chan_alloc(DSCR_CMD0_ALWAYS,
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au1x_pcm_dmatx_cb, (void *)pcd);
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au1xxx_dbdma_set_devwidth(pcd->ddma_chan, msbits);
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au1xxx_dbdma_ring_alloc(pcd->ddma_chan, 2);
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pcd->msbits = msbits;
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au1xxx_dbdma_stop(pcd->ddma_chan);
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au1xxx_dbdma_reset(pcd->ddma_chan);
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static inline struct au1xpsc_audio_dmadata *to_dmadata(struct snd_pcm_substream *ss,
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struct snd_soc_component *component)
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struct au1xpsc_audio_dmadata *pcd = snd_soc_component_get_drvdata(component);
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return &pcd[ss->stream];
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static int au1xpsc_pcm_hw_params(struct snd_soc_component *component,
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struct snd_pcm_substream *substream,
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struct snd_pcm_hw_params *params)
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct au1xpsc_audio_dmadata *pcd;
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ret = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
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stype = substream->stream;
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pcd = to_dmadata(substream, component);
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DBG("runtime->dma_area = 0x%08lx dma_addr_t = 0x%08lx dma_size = %zu "
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"runtime->min_align %lu\n",
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(unsigned long)runtime->dma_area,
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(unsigned long)runtime->dma_addr, runtime->dma_bytes,
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DBG("bits %d frags %d frag_bytes %d is_rx %d\n", params->msbits,
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params_periods(params), params_period_bytes(params), stype);
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ret = au1x_pcm_dbdma_realloc(pcd, stype, params->msbits);
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MSG("DDMA channel (re)alloc failed!\n");
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pcd->substream = substream;
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pcd->period_bytes = params_period_bytes(params);
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pcd->periods = params_periods(params);
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pcd->dma_area_s = pcd->dma_area = runtime->dma_addr;
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pcd->curr_period = 0;
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static int au1xpsc_pcm_hw_free(struct snd_soc_component *component,
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struct snd_pcm_substream *substream)
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snd_pcm_lib_free_pages(substream);
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static int au1xpsc_pcm_prepare(struct snd_soc_component *component,
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struct snd_pcm_substream *substream)
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struct au1xpsc_audio_dmadata *pcd = to_dmadata(substream, component);
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au1xxx_dbdma_reset(pcd->ddma_chan);
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if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
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au1x_pcm_queue_rx(pcd);
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au1x_pcm_queue_rx(pcd);
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au1x_pcm_queue_tx(pcd);
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au1x_pcm_queue_tx(pcd);
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static int au1xpsc_pcm_trigger(struct snd_soc_component *component,
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struct snd_pcm_substream *substream, int cmd)
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u32 c = to_dmadata(substream, component)->ddma_chan;
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case SNDRV_PCM_TRIGGER_START:
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case SNDRV_PCM_TRIGGER_RESUME:
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au1xxx_dbdma_start(c);
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case SNDRV_PCM_TRIGGER_STOP:
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case SNDRV_PCM_TRIGGER_SUSPEND:
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au1xxx_dbdma_stop(c);
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static snd_pcm_uframes_t
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au1xpsc_pcm_pointer(struct snd_soc_component *component,
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struct snd_pcm_substream *substream)
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return bytes_to_frames(substream->runtime,
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to_dmadata(substream, component)->pos);
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static int au1xpsc_pcm_open(struct snd_soc_component *component,
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struct snd_pcm_substream *substream)
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struct au1xpsc_audio_dmadata *pcd = to_dmadata(substream, component);
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struct snd_soc_pcm_runtime *rtd = substream->private_data;
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int stype = substream->stream, *dmaids;
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dmaids = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
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return -ENODEV; /* whoa, has ordering changed? */
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pcd->ddma_id = dmaids[stype];
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snd_soc_set_runtime_hwparams(substream, &au1xpsc_pcm_hardware);
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static int au1xpsc_pcm_close(struct snd_soc_component *component,
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struct snd_pcm_substream *substream)
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au1x_pcm_dbdma_free(to_dmadata(substream, component));
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static int au1xpsc_pcm_new(struct snd_soc_component *component,
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struct snd_soc_pcm_runtime *rtd)
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struct snd_card *card = rtd->card->snd_card;
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struct snd_pcm *pcm = rtd->pcm;
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snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
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card->dev, AU1XPSC_BUFFER_MIN_BYTES, (4096 * 1024) - 1);
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/* au1xpsc audio platform */
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static struct snd_soc_component_driver au1xpsc_soc_component = {
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.open = au1xpsc_pcm_open,
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.close = au1xpsc_pcm_close,
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.ioctl = snd_soc_pcm_lib_ioctl,
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.hw_params = au1xpsc_pcm_hw_params,
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.hw_free = au1xpsc_pcm_hw_free,
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.prepare = au1xpsc_pcm_prepare,
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.trigger = au1xpsc_pcm_trigger,
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.pointer = au1xpsc_pcm_pointer,
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.pcm_construct = au1xpsc_pcm_new,
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static int au1xpsc_pcm_drvprobe(struct platform_device *pdev)
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struct au1xpsc_audio_dmadata *dmadata;
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dmadata = devm_kcalloc(&pdev->dev,
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2, sizeof(struct au1xpsc_audio_dmadata),
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platform_set_drvdata(pdev, dmadata);
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return devm_snd_soc_register_component(&pdev->dev,
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&au1xpsc_soc_component, NULL, 0);
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static struct platform_driver au1xpsc_pcm_driver = {
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.name = "au1xpsc-pcm",
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.probe = au1xpsc_pcm_drvprobe,
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module_platform_driver(au1xpsc_pcm_driver);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Au12x0/Au1550 PSC Audio DMA driver");
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MODULE_AUTHOR("Manuel Lauss");