[alsa-devel] [PATCH 03/11] ALSA: vsnd: Read sound driver configuration from Xen store

7 Aug 2017

From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
Read configuration values from Xen store according
to xen/interface/io/sndif.h protocol:
- introduce configuration structures for different
  components, e.g. sound card, device, stream
- read PCM HW parameters, e.g rate, format etc.
- detect stream type (capture/playback)
- read device and card parameters
Fill in platform data with the configuration read, so
it can be passed to sound driver later.
Signed-off-by: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
---
 sound/drivers/xen-front.c | 530 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 530 insertions(+)

diff --git a/sound/drivers/xen-front.c b/sound/drivers/xen-front.c
index c4fd21cac3a7..ef48cbf44cf2 100644
--- a/sound/drivers/xen-front.c
+++ b/sound/drivers/xen-front.c
@@ -20,24 +20,554 @@
#include <linux/module.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+
 #include <xen/platform_pci.h>
 #include <xen/xen.h>
 #include <xen/xenbus.h>
#include <xen/interface/io/sndif.h>
+/* maximum number of supported streams */
+#define VSND_MAX_STREAM		8
+
+struct cfg_stream {
+	int unique_id;
+	char *xenstore_path;
+	struct snd_pcm_hardware pcm_hw;
+};
+
+struct cfg_pcm_instance {
+	char name[80];
+	int device_id;
+	struct snd_pcm_hardware pcm_hw;
+	int  num_streams_pb;
+	struct cfg_stream *streams_pb;
+	int  num_streams_cap;
+	struct cfg_stream *streams_cap;
+};
+
+struct cfg_card {
+	char name_short[32];
+	char name_long[80];
+	struct snd_pcm_hardware pcm_hw;
+	int num_pcm_instances;
+	struct cfg_pcm_instance *pcm_instances;
+};
+
+struct sdev_card_plat_data {
+	struct xdrv_info *xdrv_info;
+	struct cfg_card cfg_card;
+};
+
 struct xdrv_info {
    struct xenbus_device *xb_dev;
    spinlock_t io_lock;
    struct mutex mutex;
+	struct sdev_card_plat_data cfg_plat_data;
 };
+#define MAX_XEN_BUFFER_SIZE	(64 * 1024)
+#define MAX_BUFFER_SIZE		MAX_XEN_BUFFER_SIZE
+#define MIN_PERIOD_SIZE		64
+#define MAX_PERIOD_SIZE		(MAX_BUFFER_SIZE / 8)
+#define USE_FORMATS		(SNDRV_PCM_FMTBIT_U8 | \
+				 SNDRV_PCM_FMTBIT_S16_LE)
+#define USE_RATE		(SNDRV_PCM_RATE_CONTINUOUS | \
+				 SNDRV_PCM_RATE_8000_48000)
+#define USE_RATE_MIN		5512
+#define USE_RATE_MAX		48000
+#define USE_CHANNELS_MIN	1
+#define USE_CHANNELS_MAX	2
+#define USE_PERIODS_MIN		2
+#define USE_PERIODS_MAX		8
+
+static struct snd_pcm_hardware sdrv_pcm_hw_default = {
+	.info = (SNDRV_PCM_INFO_MMAP |
+		 SNDRV_PCM_INFO_INTERLEAVED |
+		 SNDRV_PCM_INFO_RESUME |
+		 SNDRV_PCM_INFO_MMAP_VALID),
+	.formats = USE_FORMATS,
+	.rates = USE_RATE,
+	.rate_min = USE_RATE_MIN,
+	.rate_max = USE_RATE_MAX,
+	.channels_min = USE_CHANNELS_MIN,
+	.channels_max = USE_CHANNELS_MAX,
+	.buffer_bytes_max = MAX_BUFFER_SIZE,
+	.period_bytes_min = MIN_PERIOD_SIZE,
+	.period_bytes_max = MAX_PERIOD_SIZE,
+	.periods_min = USE_PERIODS_MIN,
+	.periods_max = USE_PERIODS_MAX,
+	.fifo_size = 0,
+};
+
+struct CFG_HW_SAMPLE_RATE {
+	const char *name;
+	unsigned int mask;
+	unsigned int value;
+};
+
+static struct CFG_HW_SAMPLE_RATE cfg_hw_supported_rates[] = {
+	{ .name = "5512",   .mask = SNDRV_PCM_RATE_5512,   .value = 5512 },
+	{ .name = "8000",   .mask = SNDRV_PCM_RATE_8000,   .value = 8000 },
+	{ .name = "11025",  .mask = SNDRV_PCM_RATE_11025,  .value = 11025 },
+	{ .name = "16000",  .mask = SNDRV_PCM_RATE_16000,  .value = 16000 },
+	{ .name = "22050",  .mask = SNDRV_PCM_RATE_22050,  .value = 22050 },
+	{ .name = "32000",  .mask = SNDRV_PCM_RATE_32000,  .value = 32000 },
+	{ .name = "44100",  .mask = SNDRV_PCM_RATE_44100,  .value = 44100 },
+	{ .name = "48000",  .mask = SNDRV_PCM_RATE_48000,  .value = 48000 },
+	{ .name = "64000",  .mask = SNDRV_PCM_RATE_64000,  .value = 64000 },
+	{ .name = "96000",  .mask = SNDRV_PCM_RATE_96000,  .value = 96000 },
+	{ .name = "176400", .mask = SNDRV_PCM_RATE_176400, .value = 176400 },
+	{ .name = "192000", .mask = SNDRV_PCM_RATE_192000, .value = 192000 },
+};
+
+struct CFG_HW_SAMPLE_FORMAT {
+	const char *name;
+	u64 mask;
+};
+
+static struct CFG_HW_SAMPLE_FORMAT cfg_hw_supported_formats[] = {
+	{
+		.name = XENSND_PCM_FORMAT_U8_STR,
+		.mask = SNDRV_PCM_FMTBIT_U8
+	},
+	{
+		.name = XENSND_PCM_FORMAT_S8_STR,
+		.mask = SNDRV_PCM_FMTBIT_S8
+	},
+	{
+		.name = XENSND_PCM_FORMAT_U16_LE_STR,
+		.mask = SNDRV_PCM_FMTBIT_U16_LE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_U16_BE_STR,
+		.mask = SNDRV_PCM_FMTBIT_U16_BE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_S16_LE_STR,
+		.mask = SNDRV_PCM_FMTBIT_S16_LE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_S16_BE_STR,
+		.mask = SNDRV_PCM_FMTBIT_S16_BE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_U24_LE_STR,
+		.mask = SNDRV_PCM_FMTBIT_U24_LE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_U24_BE_STR,
+		.mask = SNDRV_PCM_FMTBIT_U24_BE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_S24_LE_STR,
+		.mask = SNDRV_PCM_FMTBIT_S24_LE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_S24_BE_STR,
+		.mask = SNDRV_PCM_FMTBIT_S24_BE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_U32_LE_STR,
+		.mask = SNDRV_PCM_FMTBIT_U32_LE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_U32_BE_STR,
+		.mask = SNDRV_PCM_FMTBIT_U32_BE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_S32_LE_STR,
+		.mask = SNDRV_PCM_FMTBIT_S32_LE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_S32_BE_STR,
+		.mask = SNDRV_PCM_FMTBIT_S32_BE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_A_LAW_STR,
+		.mask = SNDRV_PCM_FMTBIT_A_LAW
+	},
+	{
+		.name = XENSND_PCM_FORMAT_MU_LAW_STR,
+		.mask = SNDRV_PCM_FMTBIT_MU_LAW
+	},
+	{
+		.name = XENSND_PCM_FORMAT_F32_LE_STR,
+		.mask = SNDRV_PCM_FMTBIT_FLOAT_LE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_F32_BE_STR,
+		.mask = SNDRV_PCM_FMTBIT_FLOAT_BE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_F64_LE_STR,
+		.mask = SNDRV_PCM_FMTBIT_FLOAT64_LE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_F64_BE_STR,
+		.mask = SNDRV_PCM_FMTBIT_FLOAT64_BE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_IEC958_SUBFRAME_LE_STR,
+		.mask = SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_IEC958_SUBFRAME_BE_STR,
+		.mask = SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_BE
+	},
+	{
+		.name = XENSND_PCM_FORMAT_IMA_ADPCM_STR,
+		.mask = SNDRV_PCM_FMTBIT_IMA_ADPCM
+	},
+	{
+		.name = XENSND_PCM_FORMAT_MPEG_STR,
+		.mask = SNDRV_PCM_FMTBIT_MPEG
+	},
+	{
+		.name = XENSND_PCM_FORMAT_GSM_STR,
+		.mask = SNDRV_PCM_FMTBIT_GSM
+	},
+};
+
+static void cfg_hw_rates(char *list, unsigned int len,
+	const char *path, struct snd_pcm_hardware *pcm_hw)
+{
+	char *cur_rate;
+	unsigned int cur_mask;
+	unsigned int cur_value;
+	unsigned int rates;
+	unsigned int rate_min;
+	unsigned int rate_max;
+	int i;
+
+	rates = 0;
+	rate_min = -1;
+	rate_max = 0;
+	while ((cur_rate = strsep(&list, XENSND_LIST_SEPARATOR))) {
+		for (i = 0; i < ARRAY_SIZE(cfg_hw_supported_rates); i++)
+			if (!strncasecmp(cur_rate,
+					cfg_hw_supported_rates[i].name,
+					XENSND_SAMPLE_RATE_MAX_LEN)) {
+				cur_mask = cfg_hw_supported_rates[i].mask;
+				cur_value = cfg_hw_supported_rates[i].value;
+				rates |= cur_mask;
+				if (rate_min > cur_value)
+					rate_min = cur_value;
+				if (rate_max < cur_value)
+					rate_max = cur_value;
+			}
+	}
+
+	if (rates) {
+		pcm_hw->rates = rates;
+		pcm_hw->rate_min = rate_min;
+		pcm_hw->rate_max = rate_max;
+	}
+}
+
+static void cfg_formats(char *list, unsigned int len,
+	const char *path, struct snd_pcm_hardware *pcm_hw)
+{
+	u64 formats;
+	char *cur_format;
+	int i;
+
+	formats = 0;
+	while ((cur_format = strsep(&list, XENSND_LIST_SEPARATOR))) {
+		for (i = 0; i < ARRAY_SIZE(cfg_hw_supported_formats); i++)
+			if (!strncasecmp(cur_format,
+					cfg_hw_supported_formats[i].name,
+					XENSND_SAMPLE_FORMAT_MAX_LEN))
+				formats |= cfg_hw_supported_formats[i].mask;
+	}
+
+	if (formats)
+		pcm_hw->formats = formats;
+}
+
+static void cfg_pcm_hw(const char *path,
+	struct snd_pcm_hardware *parent_pcm_hw,
+	struct snd_pcm_hardware *pcm_hw)
+{
+	char *list;
+	int val;
+	size_t buf_sz;
+	unsigned int len;
+
+	/* inherit parent's PCM HW and read overrides if any */
+	*pcm_hw = *parent_pcm_hw;
+
+	val = xenbus_read_unsigned(path, XENSND_FIELD_CHANNELS_MIN, 0);
+	if (val)
+		pcm_hw->channels_min = val;
+
+	val = xenbus_read_unsigned(path, XENSND_FIELD_CHANNELS_MAX, 0);
+	if (val)
+		pcm_hw->channels_max = val;
+
+	list = xenbus_read(XBT_NIL, path, XENSND_FIELD_SAMPLE_RATES, &len);
+	if (!IS_ERR(list)) {
+		cfg_hw_rates(list, len, path, pcm_hw);
+		kfree(list);
+	}
+
+	list = xenbus_read(XBT_NIL, path, XENSND_FIELD_SAMPLE_FORMATS, &len);
+	if (!IS_ERR(list)) {
+		cfg_formats(list, len, path, pcm_hw);
+		kfree(list);
+	}
+
+	buf_sz = xenbus_read_unsigned(path, XENSND_FIELD_BUFFER_SIZE, 0);
+	if (buf_sz)
+		pcm_hw->buffer_bytes_max = buf_sz;
+}
+
+static int cfg_get_stream_type(const char *path, int index,
+	int *num_pb, int *num_cap)
+{
+	char *str = NULL;
+	char *stream_path;
+	int ret;
+
+	*num_pb = 0;
+	*num_cap = 0;
+	stream_path = kasprintf(GFP_KERNEL, "%s/%d", path, index);
+	if (!stream_path) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	str = xenbus_read(XBT_NIL, stream_path, XENSND_FIELD_TYPE, NULL);
+	if (IS_ERR(str)) {
+		ret = -EINVAL;
+		goto fail;
+	}
+
+	if (!strncasecmp(str, XENSND_STREAM_TYPE_PLAYBACK,
+		sizeof(XENSND_STREAM_TYPE_PLAYBACK)))
+		(*num_pb)++;
+	else if (!strncasecmp(str, XENSND_STREAM_TYPE_CAPTURE,
+		sizeof(XENSND_STREAM_TYPE_CAPTURE)))
+		(*num_cap)++;
+	else {
+		ret = -EINVAL;
+		goto fail;
+	}
+	ret = 0;
+
+fail:
+	kfree(stream_path);
+	kfree(str);
+	return ret;
+}
+
+static int cfg_stream(struct xdrv_info *drv_info,
+	struct cfg_pcm_instance *pcm_instance,
+	const char *path, int index, int *cur_pb, int *cur_cap,
+	int *stream_idx)
+{
+	char *str = NULL;
+	char *stream_path;
+	struct cfg_stream *stream;
+	int ret;
+
+	stream_path = devm_kasprintf(&drv_info->xb_dev->dev,
+		GFP_KERNEL, "%s/%d", path, index);
+	if (!stream_path) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	str = xenbus_read(XBT_NIL, stream_path, XENSND_FIELD_TYPE, NULL);
+	if (IS_ERR(str)) {
+		ret = -EINVAL;
+		goto fail;
+	}
+
+	if (!strncasecmp(str, XENSND_STREAM_TYPE_PLAYBACK,
+		sizeof(XENSND_STREAM_TYPE_PLAYBACK))) {
+		stream = &pcm_instance->streams_pb[(*cur_pb)++];
+	} else if (!strncasecmp(str, XENSND_STREAM_TYPE_CAPTURE,
+		sizeof(XENSND_STREAM_TYPE_CAPTURE))) {
+		stream = &pcm_instance->streams_cap[(*cur_cap)++];
+	} else {
+		ret = -EINVAL;
+		goto fail;
+	}
+
+	/* get next stream index */
+	stream->unique_id = (*stream_idx)++;
+	stream->xenstore_path = stream_path;
+	/*
+	 * check in Xen store if PCM HW configuration exists for this stream
+	 * and update if so, e.g. we inherit all values from device's PCM HW,
+	 * but can still override some of the values for the stream
+	 */
+	cfg_pcm_hw(stream->xenstore_path,
+		&pcm_instance->pcm_hw, &stream->pcm_hw);
+	ret = 0;
+
+fail:
+	kfree(str);
+	return ret;
+}
+
+static int cfg_device(struct xdrv_info *drv_info,
+	struct cfg_pcm_instance *pcm_instance,
+	struct snd_pcm_hardware *parent_pcm_hw,
+	const char *path, int node_index, int *stream_idx)
+{
+	char *str;
+	char *device_path;
+	int ret, i, num_streams;
+	int num_pb, num_cap;
+	int cur_pb, cur_cap;
+	char node[3];
+
+	device_path = kasprintf(GFP_KERNEL, "%s/%d", path, node_index);
+	if (!device_path)
+		return -ENOMEM;
+
+	str = xenbus_read(XBT_NIL, device_path, XENSND_FIELD_DEVICE_NAME, NULL);
+	if (!IS_ERR(str)) {
+		strncpy(pcm_instance->name, str, sizeof(pcm_instance->name));
+		kfree(str);
+	}
+
+	pcm_instance->device_id = node_index;
+
+	/*
+	 * check in Xen store if PCM HW configuration exists for this device
+	 * and update if so, e.g. we inherit all values from card's PCM HW,
+	 * but can still override some of the values for the device
+	 */
+	cfg_pcm_hw(device_path, parent_pcm_hw, &pcm_instance->pcm_hw);
+
+	/*
+	 * find out how many streams were configured in Xen store:
+	 * streams must have sequential unique IDs, so stop when one
+	 * does not exist
+	 */
+	num_streams = 0;
+	do {
+		snprintf(node, sizeof(node), "%d", num_streams);
+		if (!xenbus_exists(XBT_NIL, device_path, node))
+			break;
+
+		num_streams++;
+	} while (num_streams < VSND_MAX_STREAM);
+
+	pcm_instance->num_streams_pb = 0;
+	pcm_instance->num_streams_cap = 0;
+	/* get number of playback and capture streams */
+	for (i = 0; i < num_streams; i++) {
+		ret = cfg_get_stream_type(device_path, i, &num_pb, &num_cap);
+		if (ret < 0)
+			goto fail;
+
+		pcm_instance->num_streams_pb += num_pb;
+		pcm_instance->num_streams_cap += num_cap;
+	}
+
+	if (pcm_instance->num_streams_pb) {
+		pcm_instance->streams_pb = devm_kcalloc(
+			&drv_info->xb_dev->dev,
+			pcm_instance->num_streams_pb,
+			sizeof(struct cfg_stream), GFP_KERNEL);
+		if (!pcm_instance->streams_pb) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+	}
+
+	if (pcm_instance->num_streams_cap) {
+		pcm_instance->streams_cap = devm_kcalloc(
+			&drv_info->xb_dev->dev,
+			pcm_instance->num_streams_cap,
+			sizeof(struct cfg_stream), GFP_KERNEL);
+		if (!pcm_instance->streams_cap) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+	}
+
+	cur_pb = 0;
+	cur_cap = 0;
+	for (i = 0; i < num_streams; i++) {
+		ret = cfg_stream(drv_info,
+			pcm_instance, device_path, i, &cur_pb, &cur_cap,
+			stream_idx);
+		if (ret < 0)
+			goto fail;
+	}
+	ret = 0;
+
+fail:
+	kfree(device_path);
+	return ret;
+}
+
+static int cfg_card(struct xdrv_info *drv_info,
+	struct sdev_card_plat_data *plat_data, int *stream_idx)
+{
+	struct xenbus_device *xb_dev = drv_info->xb_dev;
+	int ret, num_devices, i;
+	char node[3];
+
+	num_devices = 0;
+	do {
+		snprintf(node, sizeof(node), "%d", num_devices);
+		if (!xenbus_exists(XBT_NIL, xb_dev->nodename, node))
+			break;
+
+		num_devices++;
+	} while (num_devices < SNDRV_PCM_DEVICES);
+
+	if (!num_devices) {
+		dev_warn(&xb_dev->dev,
+			"No devices configured for sound card at %s\n",
+			xb_dev->nodename);
+		return -ENODEV;
+	}
+
+	/* start from default PCM HW configuration for the card */
+	cfg_pcm_hw(xb_dev->nodename, &sdrv_pcm_hw_default,
+		&plat_data->cfg_card.pcm_hw);
+
+	plat_data->cfg_card.pcm_instances = devm_kcalloc(
+		&drv_info->xb_dev->dev, num_devices,
+		sizeof(struct cfg_pcm_instance), GFP_KERNEL);
+	if (!plat_data->cfg_card.pcm_instances)
+		return -ENOMEM;
+
+	for (i = 0; i < num_devices; i++) {
+		ret = cfg_device(drv_info,
+			&plat_data->cfg_card.pcm_instances[i],
+			&plat_data->cfg_card.pcm_hw,
+			xb_dev->nodename, i, stream_idx);
+		if (ret < 0)
+			return ret;
+	}
+	plat_data->cfg_card.num_pcm_instances = num_devices;
+	return 0;
+}
+
 static void xdrv_remove_internal(struct xdrv_info *drv_info)
 {
 }
static int xdrv_be_on_initwait(struct xdrv_info *drv_info)
 {
+	int stream_idx;
+	int ret;
+
+	drv_info->cfg_plat_data.xdrv_info = drv_info;
+	stream_idx = 0;
+	ret = cfg_card(drv_info, &drv_info->cfg_plat_data, &stream_idx);
+	if (ret < 0)
+		return ret;
    return 0;
 }
-- 
2.7.4


    