ASoC: sprd: Add Spreadtrum audio compress offload support

We use 2-stage DMA mode to support Spreadtrum audio compress offload,
which means we use one DMA source channel to transfer data from IRAM
buffer to the DSP fifo to do decoding/encoding, once IRAM buffer is
empty by transferring done, another DMA destination channel will be
triggered automatically to start to transfer data from DDR buffer to
the IRAM buffer. This can reduce the AP subsystem wakeup times to save
power.
Co-developed-by: Yintang Ren <yintang.ren@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sprd/Kconfig

 config SND_SOC_SPRD
 	tristate "SoC Audio for the Spreadtrum SoC chips"
 	depends on ARCH_SPRD || COMPILE_TEST
+	select SND_SOC_COMPRESS
 	help
 	  Say Y or M if you want to add support for codecs attached to
 	  the Spreadtrum SoCs' Audio interfaces.

sound/soc/sprd/Makefile

 # SPDX-License-Identifier: GPL-2.0
 # Spreadtrum Audio Support
 
-obj-$(CONFIG_SND_SOC_SPRD)	+= sprd-pcm-dma.o
+obj-$(CONFIG_SND_SOC_SPRD)	+= sprd-pcm-dma.o sprd-pcm-compress.o

sound/soc/sprd/sprd-pcm-compress.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2019 Spreadtrum Communications Inc.
+
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/dma/sprd-dma.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/compress_driver.h>
+
+#include "sprd-pcm-dma.h"
+
+#define SPRD_COMPR_DMA_CHANS		2
+
+/* Default values if userspace does not set */
+#define SPRD_COMPR_MIN_FRAGMENT_SIZE	SZ_8K
+#define SPRD_COMPR_MAX_FRAGMENT_SIZE	SZ_128K
+#define SPRD_COMPR_MIN_NUM_FRAGMENTS	4
+#define SPRD_COMPR_MAX_NUM_FRAGMENTS	64
+
+/* DSP FIFO size */
+#define SPRD_COMPR_MCDT_EMPTY_WMK	0
+#define SPRD_COMPR_MCDT_FIFO_SIZE	512
+
+/* Stage 0 IRAM buffer size definition */
+#define SPRD_COMPR_IRAM_BUF_SIZE	SZ_32K
+#define SPRD_COMPR_IRAM_INFO_SIZE	(sizeof(struct sprd_compr_playinfo))
+#define SPRD_COMPR_IRAM_LINKLIST_SIZE	(1024 - SPRD_COMPR_IRAM_INFO_SIZE)
+#define SPRD_COMPR_IRAM_SIZE		(SPRD_COMPR_IRAM_BUF_SIZE + \
+					 SPRD_COMPR_IRAM_INFO_SIZE + \
+					 SPRD_COMPR_IRAM_LINKLIST_SIZE)
+
+/* Stage 1 DDR buffer size definition */
+#define SPRD_COMPR_AREA_BUF_SIZE	SZ_2M
+#define SPRD_COMPR_AREA_LINKLIST_SIZE	1024
+#define SPRD_COMPR_AREA_SIZE		(SPRD_COMPR_AREA_BUF_SIZE + \
+					 SPRD_COMPR_AREA_LINKLIST_SIZE)
+
+struct sprd_compr_dma {
+	struct dma_chan *chan;
+	struct dma_async_tx_descriptor *desc;
+	dma_cookie_t cookie;
+	dma_addr_t phys;
+	void *virt;
+	int trans_len;
+};
+
+/*
+ * The Spreadtrum Audio compress offload mode will use 2-stage DMA transfer to
+ * save power. That means we can request 2 dma channels, one for source channel,
+ * and another one for destination channel. Once the source channel's transaction
+ * is done, it will trigger the destination channel's transaction automatically
+ * by hardware signal.
+ *
+ * For 2-stage DMA transfer, we can allocate 2 buffers: IRAM buffer (always
+ * power-on) and DDR buffer. The source channel will transfer data from IRAM
+ * buffer to the DSP fifo to decoding/encoding, once IRAM buffer is empty by
+ * transferring done, the destination channel will start to transfer data from
+ * DDR buffer to IRAM buffer.
+ *
+ * Since the DSP fifo is only 512B, IRAM buffer is allocated by 32K, and DDR
+ * buffer is larger to 2M. That means only the IRAM 32k data is transferred
+ * done, we can wake up the AP system to transfer data from DDR to IRAM, and
+ * other time the AP system can be suspended to save power.
+ */
+struct sprd_compr_stream {
+	struct snd_compr_stream *cstream;
+	struct sprd_compr_ops *compr_ops;
+	struct sprd_compr_dma dma[SPRD_COMPR_DMA_CHANS];
+
+	/* DMA engine channel number */
+	int num_channels;
+
+	/* Stage 0 IRAM buffer */
+	struct snd_dma_buffer iram_buffer;
+	/* Stage 1 DDR buffer */
+	struct snd_dma_buffer compr_buffer;
+
+	/* DSP play information IRAM buffer */
+	dma_addr_t info_phys;
+	void *info_area;
+	int info_size;
+
+	/* Data size copied to IRAM buffer */
+	int copied_total;
+	/* Total received data size from userspace */
+	int received_total;
+	/* Stage 0 IRAM buffer received data size */
+	int received_stage0;
+	/* Stage 1 DDR buffer received data size */
+	int received_stage1;
+	/* Stage 1 DDR buffer pointer */
+	int stage1_pointer;
+};
+
+static int sprd_platform_compr_trigger(struct snd_compr_stream *cstream,
+				       int cmd);
+
+static void sprd_platform_compr_drain_notify(void *arg)
+{
+	struct snd_compr_stream *cstream = arg;
+	struct snd_compr_runtime *runtime = cstream->runtime;
+	struct sprd_compr_stream *stream = runtime->private_data;
+
+	memset(stream->info_area, 0, sizeof(struct sprd_compr_playinfo));
+
+	if (cstream)
+		snd_compr_drain_notify(cstream);
+}
+
+static void sprd_platform_compr_dma_complete(void *data)
+{
+	struct snd_compr_stream *cstream = data;
+	struct snd_compr_runtime *runtime = cstream->runtime;
+	struct sprd_compr_stream *stream = runtime->private_data;
+	struct sprd_compr_dma *dma = &stream->dma[1];
+
+	/* Update data size copied to IRAM buffer */
+	stream->copied_total += dma->trans_len;
+	if (stream->copied_total > stream->received_total)
+		stream->copied_total = stream->received_total;
+
+	snd_compr_fragment_elapsed(cstream);
+}
+
+static int sprd_platform_compr_dma_config(struct snd_compr_stream *cstream,
+					  struct snd_compr_params *params,
+					  int channel)
+{
+	struct snd_compr_runtime *runtime = cstream->runtime;
+	struct sprd_compr_stream *stream = runtime->private_data;
+	struct snd_soc_pcm_runtime *rtd = cstream->private_data;
+	struct snd_soc_component *component =
+		snd_soc_rtdcom_lookup(rtd, DRV_NAME);
+	struct device *dev = component->dev;
+	struct sprd_compr_data *data = snd_soc_dai_get_drvdata(rtd->cpu_dai);
+	struct sprd_pcm_dma_params *dma_params = data->dma_params;
+	struct sprd_compr_dma *dma = &stream->dma[channel];
+	struct dma_slave_config config = { };
+	struct sprd_dma_linklist link = { };
+	enum dma_transfer_direction dir;
+	struct scatterlist *sg, *sgt;
+	enum dma_slave_buswidth bus_width;
+	int period, period_cnt, sg_num = 2;
+	dma_addr_t src_addr, dst_addr;
+	unsigned long flags;
+	int ret, j;
+
+	if (!dma_params) {
+		dev_err(dev, "no dma parameters setting\n");
+		return -EINVAL;
+	}
+
+	dma->chan = dma_request_slave_channel(dev,
+					      dma_params->chan_name[channel]);
+	if (!dma->chan) {
+		dev_err(dev, "failed to request dma channel\n");
+		return -ENODEV;
+	}
+
+	sgt = sg = devm_kcalloc(dev, sg_num, sizeof(*sg), GFP_KERNEL);
+	if (!sg) {
+		ret = -ENOMEM;
+		goto sg_err;
+	}
+
+	switch (channel) {
+	case 0:
+		bus_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		period = (SPRD_COMPR_MCDT_FIFO_SIZE - SPRD_COMPR_MCDT_EMPTY_WMK) * 4;
+		period_cnt = params->buffer.fragment_size / period;
+		src_addr = stream->iram_buffer.addr;
+		dst_addr = dma_params->dev_phys[channel];
+		flags = SPRD_DMA_FLAGS(SPRD_DMA_SRC_CHN1,
+				       SPRD_DMA_TRANS_DONE_TRG,
+				       SPRD_DMA_FRAG_REQ,
+				       SPRD_DMA_TRANS_INT);
+		break;
+
+	case 1:
+		bus_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+		period = params->buffer.fragment_size;
+		period_cnt = params->buffer.fragments;
+		src_addr = stream->compr_buffer.addr;
+		dst_addr = stream->iram_buffer.addr;
+		flags = SPRD_DMA_FLAGS(SPRD_DMA_DST_CHN1,
+				       SPRD_DMA_TRANS_DONE_TRG,
+				       SPRD_DMA_FRAG_REQ,
+				       SPRD_DMA_TRANS_INT);
+		break;
+
+	default:
+		ret = -EINVAL;
+		goto config_err;
+	}
+
+	dma->trans_len = period * period_cnt;
+
+	config.src_maxburst = period;
+	config.src_addr_width = bus_width;
+	config.dst_addr_width = bus_width;
+	if (cstream->direction == SND_COMPRESS_PLAYBACK) {
+		config.src_addr = src_addr;
+		config.dst_addr = dst_addr;
+		dir = DMA_MEM_TO_DEV;
+	} else {
+		config.src_addr = dst_addr;
+		config.dst_addr = src_addr;
+		dir = DMA_DEV_TO_MEM;
+	}
+
+	sg_init_table(sgt, sg_num);
+	for (j = 0; j < sg_num; j++, sgt++) {
+		sg_dma_len(sgt) = dma->trans_len;
+		sg_dma_address(sgt) = dst_addr;
+	}
+
+	/*
+	 * Configure the link-list address for the DMA engine link-list
+	 * mode.
+	 */
+	link.virt_addr = (unsigned long)dma->virt;
+	link.phy_addr = dma->phys;
+
+	ret = dmaengine_slave_config(dma->chan, &config);
+	if (ret) {
+		dev_err(dev,
+			"failed to set slave configuration: %d\n", ret);
+		goto config_err;
+	}
+
+	/*
+	 * We configure the DMA request mode, interrupt mode, channel
+	 * mode and channel trigger mode by the flags.
+	 */
+	dma->desc = dma->chan->device->device_prep_slave_sg(dma->chan, sg,
+							    sg_num, dir,
+							    flags, &link);
+	if (!dma->desc) {
+		dev_err(dev, "failed to prepare slave sg\n");
+		ret = -ENOMEM;
+		goto config_err;
+	}
+
+	/* Only channel 1 transfer can wake up the AP system. */
+	if (!params->no_wake_mode && channel == 1) {
+		dma->desc->callback = sprd_platform_compr_dma_complete;
+		dma->desc->callback_param = cstream;
+	}
+
+	devm_kfree(dev, sg);
+
+	return 0;
+
+config_err:
+	devm_kfree(dev, sg);
+sg_err:
+	dma_release_channel(dma->chan);
+	return ret;
+}
+
+static int sprd_platform_compr_set_params(struct snd_compr_stream *cstream,
+					  struct snd_compr_params *params)
+{
+	struct snd_compr_runtime *runtime = cstream->runtime;
+	struct sprd_compr_stream *stream = runtime->private_data;
+	struct snd_soc_pcm_runtime *rtd = cstream->private_data;
+	struct snd_soc_component *component =
+		snd_soc_rtdcom_lookup(rtd, DRV_NAME);
+	struct device *dev = component->dev;
+	struct sprd_compr_params compr_params = { };
+	int ret;
+
+	/*
+	 * Configure the DMA engine 2-stage transfer mode. Channel 1 set as the
+	 * destination channel, and channel 0 set as the source channel, that
+	 * means once the source channel's transaction is done, it will trigger
+	 * the destination channel's transaction automatically.
+	 */
+	ret = sprd_platform_compr_dma_config(cstream, params, 1);
+	if (ret) {
+		dev_err(dev, "faied to config stage 1 DMA: %d\n", ret);
+		return ret;
+	}
+
+	ret = sprd_platform_compr_dma_config(cstream, params, 0);
+	if (ret) {
+		dev_err(dev, "faied to config stage 0 DMA: %d\n", ret);
+		goto config_err;
+	}
+
+	compr_params.direction = cstream->direction;
+	compr_params.sample_rate = params->codec.sample_rate;
+	compr_params.channels = stream->num_channels;
+	compr_params.info_phys = stream->info_phys;
+	compr_params.info_size = stream->info_size;
+	compr_params.rate = params->codec.bit_rate;
+	compr_params.format = params->codec.id;
+
+	ret = stream->compr_ops->set_params(cstream->direction, &compr_params);
+	if (ret) {
+		dev_err(dev, "failed to set parameters: %d\n", ret);
+		goto params_err;
+	}
+
+	return 0;
+
+params_err:
+	dma_release_channel(stream->dma[0].chan);
+config_err:
+	dma_release_channel(stream->dma[1].chan);
+	return ret;
+}
+
+static int sprd_platform_compr_open(struct snd_compr_stream *cstream)
+{
+	struct snd_compr_runtime *runtime = cstream->runtime;
+	struct snd_soc_pcm_runtime *rtd = cstream->private_data;
+	struct snd_soc_component *component =
+		snd_soc_rtdcom_lookup(rtd, DRV_NAME);
+	struct device *dev = component->dev;
+	struct sprd_compr_data *data = snd_soc_dai_get_drvdata(rtd->cpu_dai);
+	struct sprd_compr_stream *stream;
+	struct sprd_compr_callback cb;
+	int stream_id = cstream->direction, ret;
+
+	ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
+
+	stream = devm_kzalloc(dev, sizeof(*stream), GFP_KERNEL);
+	if (!stream)
+		return -ENOMEM;
+
+	stream->cstream = cstream;
+	stream->num_channels = 2;
+	stream->compr_ops = data->ops;
+
+	/*
+	 * Allocate the stage 0 IRAM buffer size, including the DMA 0
+	 * link-list size and play information of DSP address size.
+	 */
+	ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV_IRAM, dev,
+				  SPRD_COMPR_IRAM_SIZE, &stream->iram_buffer);
+	if (ret < 0)
+		goto err_iram;
+
+	/* Use to save link-list configuration for DMA 0. */
+	stream->dma[0].virt = stream->iram_buffer.area + SPRD_COMPR_IRAM_SIZE;
+	stream->dma[0].phys = stream->iram_buffer.addr + SPRD_COMPR_IRAM_SIZE;
+
+	/* Use to update the current data offset of DSP. */
+	stream->info_phys = stream->iram_buffer.addr + SPRD_COMPR_IRAM_SIZE +
+		SPRD_COMPR_IRAM_LINKLIST_SIZE;
+	stream->info_area = stream->iram_buffer.area + SPRD_COMPR_IRAM_SIZE +
+		SPRD_COMPR_IRAM_LINKLIST_SIZE;
+	stream->info_size = SPRD_COMPR_IRAM_INFO_SIZE;
+
+	/*
+	 * Allocate the stage 1 DDR buffer size, including the DMA 1 link-list
+	 * size.
+	 */
+	ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, dev,
+				  SPRD_COMPR_AREA_SIZE, &stream->compr_buffer);
+	if (ret < 0)
+		goto err_compr;
+
+	/* Use to save link-list configuration for DMA 1. */
+	stream->dma[1].virt = stream->compr_buffer.area + SPRD_COMPR_AREA_SIZE;
+	stream->dma[1].phys = stream->compr_buffer.addr + SPRD_COMPR_AREA_SIZE;
+
+	cb.drain_notify = sprd_platform_compr_drain_notify;
+	cb.drain_data = cstream;
+	ret = stream->compr_ops->open(stream_id, &cb);
+	if (ret) {
+		dev_err(dev, "failed to open compress platform: %d\n", ret);
+		goto err_open;
+	}
+
+	runtime->private_data = stream;
+	return 0;
+
+err_open:
+	snd_dma_free_pages(&stream->compr_buffer);
+err_compr:
+	snd_dma_free_pages(&stream->iram_buffer);
+err_iram:
+	devm_kfree(dev, stream);
+
+	return ret;
+}
+
+static int sprd_platform_compr_free(struct snd_compr_stream *cstream)
+{
+	struct snd_compr_runtime *runtime = cstream->runtime;
+	struct sprd_compr_stream *stream = runtime->private_data;
+	struct snd_soc_pcm_runtime *rtd = cstream->private_data;
+	struct snd_soc_component *component =
+		snd_soc_rtdcom_lookup(rtd, DRV_NAME);
+	struct device *dev = component->dev;
+	int stream_id = cstream->direction, i;
+
+	for (i = 0; i < stream->num_channels; i++) {
+		struct sprd_compr_dma *dma = &stream->dma[i];
+
+		if (dma->chan) {
+			dma_release_channel(dma->chan);
+			dma->chan = NULL;
+		}
+	}
+
+	snd_dma_free_pages(&stream->compr_buffer);
+	snd_dma_free_pages(&stream->iram_buffer);
+
+	stream->compr_ops->close(stream_id);
+
+	devm_kfree(dev, stream);
+	return 0;
+}
+
+static int sprd_platform_compr_trigger(struct snd_compr_stream *cstream,
+				       int cmd)
+{
+	struct snd_compr_runtime *runtime = cstream->runtime;
+	struct sprd_compr_stream *stream = runtime->private_data;
+	struct snd_soc_pcm_runtime *rtd = cstream->private_data;
+	struct snd_soc_component *component =
+		snd_soc_rtdcom_lookup(rtd, DRV_NAME);
+	struct device *dev = component->dev;
+	int channels = stream->num_channels, ret = 0, i;
+	int stream_id = cstream->direction;
+
+	if (cstream->direction != SND_COMPRESS_PLAYBACK) {
+		dev_err(dev, "unsupported compress direction\n");
+		return -EINVAL;
+	}
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		for (i = channels - 1; i >= 0; i--) {
+			struct sprd_compr_dma *dma = &stream->dma[i];
+
+			if (!dma->desc)
+				continue;
+
+			dma->cookie = dmaengine_submit(dma->desc);
+			ret = dma_submit_error(dma->cookie);
+			if (ret) {
+				dev_err(dev, "failed to submit request: %d\n",
+					ret);
+				return ret;
+			}
+		}
+
+		for (i = channels - 1; i >= 0; i--) {
+			struct sprd_compr_dma *dma = &stream->dma[i];
+
+			if (dma->chan)
+				dma_async_issue_pending(dma->chan);
+		}
+
+		ret = stream->compr_ops->start(stream_id);
+		break;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+		for (i = channels - 1; i >= 0; i--) {
+			struct sprd_compr_dma *dma = &stream->dma[i];
+
+			if (dma->chan)
+				dmaengine_terminate_async(dma->chan);
+		}
+
+		stream->copied_total = 0;
+		stream->stage1_pointer  = 0;
+		stream->received_total = 0;
+		stream->received_stage0 = 0;
+		stream->received_stage1 = 0;
+
+		ret = stream->compr_ops->stop(stream_id);
+		break;
+
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		for (i = channels - 1; i >= 0; i--) {
+			struct sprd_compr_dma *dma = &stream->dma[i];
+
+			if (dma->chan)
+				dmaengine_pause(dma->chan);
+		}
+
+		ret = stream->compr_ops->pause(stream_id);
+		break;
+
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		for (i = channels - 1; i >= 0; i--) {
+			struct sprd_compr_dma *dma = &stream->dma[i];
+
+			if (dma->chan)
+				dmaengine_resume(dma->chan);
+		}
+
+		ret = stream->compr_ops->pause_release(stream_id);
+		break;
+
+	case SND_COMPR_TRIGGER_PARTIAL_DRAIN:
+	case SND_COMPR_TRIGGER_DRAIN:
+		ret = stream->compr_ops->drain(stream->received_total);
+		break;
+
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static int sprd_platform_compr_pointer(struct snd_compr_stream *cstream,
+				       struct snd_compr_tstamp *tstamp)
+{
+	struct snd_compr_runtime *runtime = cstream->runtime;
+	struct sprd_compr_stream *stream = runtime->private_data;
+	struct sprd_compr_playinfo *info =
+		(struct sprd_compr_playinfo *)stream->info_area;
+
+	tstamp->copied_total = stream->copied_total;
+	tstamp->pcm_io_frames = info->current_data_offset;
+
+	return 0;
+}
+
+static int sprd_platform_compr_copy(struct snd_compr_stream *cstream,
+				    char __user *buf, size_t count)
+{
+	struct snd_compr_runtime *runtime = cstream->runtime;
+	struct sprd_compr_stream *stream = runtime->private_data;
+	int avail_bytes, data_count = count;
+	void *dst;
+
+	/*
+	 * We usually set fragment size as 32K, and the stage 0 IRAM buffer
+	 * size is 32K too. So if now the received data size of the stage 0
+	 * IRAM buffer is less than 32K, that means we have some available
+	 * spaces for the stage 0 IRAM buffer.
+	 */
+	if (stream->received_stage0 < runtime->fragment_size) {
+		avail_bytes = runtime->fragment_size - stream->received_stage0;
+		dst = stream->iram_buffer.area + stream->received_stage0;
+
+		if (avail_bytes >= data_count) {
+			/*
+			 * Copy data to the stage 0 IRAM buffer directly if
+			 * spaces are enough.
+			 */
+			if (copy_from_user(dst, buf, data_count))
+				return -EFAULT;
+
+			stream->received_stage0 += data_count;
+			stream->copied_total += data_count;
+			goto copy_done;
+		} else {
+			/*
+			 * If the data count is larger than the available spaces
+			 * of the the stage 0 IRAM buffer, we should copy one
+			 * partial data to the stage 0 IRAM buffer, and copy
+			 * the left to the stage 1 DDR buffer.
+			 */
+			if (copy_from_user(dst, buf, avail_bytes))
+				return -EFAULT;
+
+			data_count -= avail_bytes;
+			stream->received_stage0 += avail_bytes;
+			stream->copied_total += avail_bytes;
+			buf += avail_bytes;
+		}
+	}
+
+	/*
+	 * Copy data to the stage 1 DDR buffer if no spaces for the stage 0 IRAM
+	 * buffer.
+	 */
+	dst = stream->compr_buffer.area + stream->stage1_pointer;
+	if (data_count < stream->compr_buffer.bytes - stream->stage1_pointer) {
+		if (copy_from_user(dst, buf, data_count))
+			return -EFAULT;
+
+		stream->stage1_pointer += data_count;
+	} else {
+		avail_bytes = stream->compr_buffer.bytes - stream->stage1_pointer;
+
+		if (copy_from_user(dst, buf, avail_bytes))
+			return -EFAULT;
+
+		if (copy_from_user(stream->compr_buffer.area, buf + avail_bytes,
+				   data_count - avail_bytes))
+			return -EFAULT;
+
+		stream->stage1_pointer = data_count - avail_bytes;
+	}
+
+	stream->received_stage1 += data_count;
+
+copy_done:
+	/* Update the copied data size. */
+	stream->received_total += count;
+	return count;
+}
+
+static int sprd_platform_compr_get_caps(struct snd_compr_stream *cstream,
+					struct snd_compr_caps *caps)
+{
+	caps->direction = cstream->direction;
+	caps->min_fragment_size = SPRD_COMPR_MIN_FRAGMENT_SIZE;
+	caps->max_fragment_size = SPRD_COMPR_MAX_FRAGMENT_SIZE;
+	caps->min_fragments = SPRD_COMPR_MIN_NUM_FRAGMENTS;
+	caps->max_fragments = SPRD_COMPR_MAX_NUM_FRAGMENTS;
+	caps->num_codecs = 2;
+	caps->codecs[0] = SND_AUDIOCODEC_MP3;
+	caps->codecs[1] = SND_AUDIOCODEC_AAC;
+
+	return 0;
+}
+
+static int
+sprd_platform_compr_get_codec_caps(struct snd_compr_stream *cstream,
+				   struct snd_compr_codec_caps *codec)
+{
+	switch (codec->codec) {
+	case SND_AUDIOCODEC_MP3:
+		codec->num_descriptors = 2;
+		codec->descriptor[0].max_ch = 2;
+		codec->descriptor[0].bit_rate[0] = 320;
+		codec->descriptor[0].bit_rate[1] = 128;
+		codec->descriptor[0].num_bitrates = 2;
+		codec->descriptor[0].profiles = 0;
+		codec->descriptor[0].modes = SND_AUDIOCHANMODE_MP3_STEREO;
+		codec->descriptor[0].formats = 0;
+		break;
+
+	case SND_AUDIOCODEC_AAC:
+		codec->num_descriptors = 2;
+		codec->descriptor[1].max_ch = 2;
+		codec->descriptor[1].bit_rate[0] = 320;
+		codec->descriptor[1].bit_rate[1] = 128;
+		codec->descriptor[1].num_bitrates = 2;
+		codec->descriptor[1].profiles = 0;
+		codec->descriptor[1].modes = 0;
+		codec->descriptor[1].formats = 0;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+const struct snd_compr_ops sprd_platform_compr_ops = {
+	.open = sprd_platform_compr_open,
+	.free = sprd_platform_compr_free,
+	.set_params = sprd_platform_compr_set_params,
+	.trigger = sprd_platform_compr_trigger,
+	.pointer = sprd_platform_compr_pointer,
+	.copy = sprd_platform_compr_copy,
+	.get_caps = sprd_platform_compr_get_caps,
+	.get_codec_caps = sprd_platform_compr_get_codec_caps,
+};
+
+MODULE_DESCRIPTION("Spreadtrum ASoC Compress Platform Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:compress-platform");

sound/soc/sprd/sprd-pcm-dma.c

@@ -13,7 +13,6 @@
 
 #include "sprd-pcm-dma.h"
 
-#define DRV_NAME			"sprd_pcm_dma"
 #define SPRD_PCM_DMA_LINKLIST_SIZE	64
 #define SPRD_PCM_DMA_BRUST_LEN		640
 
@@ -524,6 +523,7 @@ static void sprd_pcm_free(struct snd_pcm *pcm)
 static const struct snd_soc_component_driver sprd_soc_component = {
 	.name		= DRV_NAME,
 	.ops		= &sprd_pcm_ops,
+	.compr_ops	= &sprd_platform_compr_ops,
 	.pcm_new	= sprd_pcm_new,
 	.pcm_free	= sprd_pcm_free,
 };

sound/soc/sprd/sprd-pcm-dma.h

@@ -3,8 +3,11 @@
 #ifndef __SPRD_PCM_DMA_H
 #define __SPRD_PCM_DMA_H
 
+#define DRV_NAME		"sprd_pcm_dma"
 #define SPRD_PCM_CHANNEL_MAX	2
 
+extern const struct snd_compr_ops sprd_platform_compr_ops;
+
 struct sprd_pcm_dma_params {
 	dma_addr_t dev_phys[SPRD_PCM_CHANNEL_MAX];
 	u32 datawidth[SPRD_PCM_CHANNEL_MAX];
@@ -12,4 +15,44 @@ struct sprd_pcm_dma_params {
 	const char *chan_name[SPRD_PCM_CHANNEL_MAX];
 };
 
+struct sprd_compr_playinfo {
+	int total_time;
+	int current_time;
+	int total_data_length;
+	int current_data_offset;
+};
+
+struct sprd_compr_params {
+	u32 direction;
+	u32 rate;
+	u32 sample_rate;
+	u32 channels;
+	u32 format;
+	u32 period;
+	u32 periods;
+	u32 info_phys;
+	u32 info_size;
+};
+
+struct sprd_compr_callback {
+	void (*drain_notify)(void *data);
+	void *drain_data;
+};
+
+struct sprd_compr_ops {
+	int (*open)(int str_id, struct sprd_compr_callback *cb);
+	int (*close)(int str_id);
+	int (*start)(int str_id);
+	int (*stop)(int str_id);
+	int (*pause)(int str_id);
+	int (*pause_release)(int str_id);
+	int (*drain)(int received_total);
+	int (*set_params)(int str_id, struct sprd_compr_params *params);
+};
+
+struct sprd_compr_data {
+	struct sprd_compr_ops *ops;
+	struct sprd_pcm_dma_params *dma_params;
+};
+
 #endif /* __SPRD_PCM_DMA_H */