On 16/04/18 08:24, Oleksandr Andrushchenko wrote:

From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

Introduce skeleton of the para-virtualized Xen sound frontend driver.

Initial handling for Xen bus states: implement Xen bus state machine for the frontend driver according to the state diagram and recovery flow from sound para-virtualized protocol: xen/interface/io/sndif.h.

Signed-off-by: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

Only one minor nit (see below). With that addressed (or fixed when committing):

Reviewed-by: Juergen Gross jgross@suse.com

Juergen

---

sound/Kconfig | 2 + sound/Makefile | 2 +- sound/xen/Kconfig | 10 +++ sound/xen/Makefile | 5 ++ sound/xen/xen_snd_front.c | 196 ++++++++++++++++++++++++++++++++++++++++++++++ sound/xen/xen_snd_front.h | 18 +++++ 6 files changed, 232 insertions(+), 1 deletion(-) create mode 100644 sound/xen/Kconfig create mode 100644 sound/xen/Makefile create mode 100644 sound/xen/xen_snd_front.c create mode 100644 sound/xen/xen_snd_front.h

diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c new file mode 100644 index 000000000000..f406a8f52c51 --- /dev/null +++ b/sound/xen/xen_snd_front.c @@ -0,0 +1,196 @@ +static void sndback_changed(struct xenbus_device *xb_dev,

• 	    enum xenbus_state backend_state)
  

+{

• struct xen_snd_front_info *front_info = dev_get_drvdata(&xb_dev->dev);
• int ret;
• dev_dbg(&xb_dev->dev, "Backend state is %s, front is %s\n",

• xenbus_strstate(backend_state),
  

• xenbus_strstate(xb_dev->state));
  

• switch (backend_state) {
• case XenbusStateReconfiguring:

• /* fall through */
  

• case XenbusStateReconfigured:

• /* fall through */
  

• case XenbusStateInitialised:

• /* fall through */
  

• break;
  

• case XenbusStateInitialising:

• /* recovering after backend unexpected closure */
  

• sndback_disconnect(front_info);
  

• break;
  

• case XenbusStateInitWait:

• /* recovering after backend unexpected closure */
  

• sndback_disconnect(front_info);
  

• ret = sndback_initwait(front_info);
  

• if (ret < 0)
  

• 	xenbus_dev_fatal(xb_dev, ret, "initializing frontend");
  

• else
  

• 	xenbus_switch_state(xb_dev, XenbusStateInitialised);
  

• break;
  

• case XenbusStateConnected:

• if (xb_dev->state != XenbusStateInitialised)
  

• 	break;
  

• ret = sndback_connect(front_info);
  

• if (ret < 0)
  

• 	xenbus_dev_fatal(xb_dev, ret, "initializing frontend");
  

• else
  

• 	xenbus_switch_state(xb_dev, XenbusStateConnected);
  

• break;
  

• case XenbusStateClosing:

• /*
  

•  * in this state backend starts freeing resources,
  

•  * so let it go into closed state first, so we can also
  

•  * remove ours
  

•  */
  

Please start the sentence with a capital letter and end it with a full stop.

Juergen

On Mon, 16 Apr 2018 08:24:49 +0200, Oleksandr Andrushchenko wrote:

--- /dev/null +++ b/sound/xen/Kconfig @@ -0,0 +1,10 @@ +# ALSA Xen drivers

+config SND_XEN_FRONTEND

• tristate "Xen para-virtualized sound frontend driver"
• depends on XEN && SND_PCM

Please do select SND_PCM instead of depends.

• select XEN_XENBUS_FRONTEND
• default n

"default n" is superfluous, drop it.

thanks,

Takashi

On 04/16/2018 03:55 PM, Juergen Gross wrote:

On 16/04/18 08:24, Oleksandr Andrushchenko wrote:

...

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

Signed-off-by: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

sound/xen/Makefile | 3 +- sound/xen/xen_snd_front.c | 7 + sound/xen/xen_snd_front.h | 4 + sound/xen/xen_snd_front_cfg.c | 517 ++++++++++++++++++++++++++++++++++++++++++ sound/xen/xen_snd_front_cfg.h | 46 ++++ 5 files changed, 576 insertions(+), 1 deletion(-) create mode 100644 sound/xen/xen_snd_front_cfg.c create mode 100644 sound/xen/xen_snd_front_cfg.h

diff --git a/sound/xen/Makefile b/sound/xen/Makefile index 4507ef3c27fd..06705bef61fa 100644 --- a/sound/xen/Makefile +++ b/sound/xen/Makefile @@ -1,5 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 OR MIT

-snd_xen_front-objs := xen_snd_front.o +snd_xen_front-objs := xen_snd_front.o \

•       xen_snd_front_cfg.o
  
  

  obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o

diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c index f406a8f52c51..65d2494a9d14 100644 --- a/sound/xen/xen_snd_front.c +++ b/sound/xen/xen_snd_front.c @@ -25,6 +25,13 @@ static void xen_snd_drv_fini(struct xen_snd_front_info *front_info)

static int sndback_initwait(struct xen_snd_front_info *front_info) {

• int num_streams;
• int ret;
• ret = xen_snd_front_cfg_card(front_info, &num_streams);
• if (ret < 0)

• return ret;
  

• return 0; }

diff --git a/sound/xen/xen_snd_front.h b/sound/xen/xen_snd_front.h index 4ae204b23d32..b52226cb30bc 100644 --- a/sound/xen/xen_snd_front.h +++ b/sound/xen/xen_snd_front.h @@ -11,8 +11,12 @@ #ifndef __XEN_SND_FRONT_H #define __XEN_SND_FRONT_H

+#include "xen_snd_front_cfg.h"

• struct xen_snd_front_info { struct xenbus_device *xb_dev;

• struct xen_front_cfg_card cfg; };

  #endif /* __XEN_SND_FRONT_H */

diff --git a/sound/xen/xen_snd_front_cfg.c b/sound/xen/xen_snd_front_cfg.c new file mode 100644 index 000000000000..d461985afffa --- /dev/null +++ b/sound/xen/xen_snd_front_cfg.c @@ -0,0 +1,517 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT

+/*

• • Xen para-virtual sound device
• • Copyright (C) 2016-2018 EPAM Systems Inc.
• • Author: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
• */

+#include <xen/xenbus.h>

+#include <xen/interface/io/sndif.h>

+#include "xen_snd_front.h" +#include "xen_snd_front_cfg.h"

+/* maximum number of supported streams */

Comment style (multiple times below, too): Start with a capital letter and end sentences with a full stop.

will fix

...

+#define VSND_MAX_STREAM 8

+struct cfg_hw_sample_rate {

• const char *name;
• unsigned int mask;
• unsigned int value;

+};

+static const 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 const 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;
  

+}

+#define MAX_BUFFER_SIZE (64 * 1024) +#define MIN_PERIOD_SIZE 64 +#define MAX_PERIOD_SIZE MAX_BUFFER_SIZE +#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 (MAX_BUFFER_SIZE / MIN_PERIOD_SIZE)

+static const struct snd_pcm_hardware SND_DRV_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,

+};

+static void cfg_read_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 from XenStore */
• if (parent_pcm_hw)

• *pcm_hw = *parent_pcm_hw;
  

• else

• *pcm_hw = SND_DRV_PCM_HW_DEFAULT;
  

• 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;
  

• /* update configuration to match new values */
• if (pcm_hw->channels_min > pcm_hw->channels_max)

• pcm_hw->channels_min = pcm_hw->channels_max;
  

• if (pcm_hw->rate_min > pcm_hw->rate_max)

• pcm_hw->rate_min = pcm_hw->rate_max;
  

• pcm_hw->period_bytes_max = pcm_hw->buffer_bytes_max;
• pcm_hw->periods_max = pcm_hw->period_bytes_max /

• pcm_hw->period_bytes_min;
  

+}

+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;
  

Is this correct? Do you want to return -EINVAL in case xenbus_read() failed with e.g. -ENOMEM?

will return PTR_ERR(str)

...

• 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 xen_snd_front_info *front_info,

•       struct xen_front_cfg_pcm_instance *pcm_instance,
  

•       const char *path, int index, int *cur_pb, int *cur_cap,
  

•       int *stream_cnt)
  

+{

• char *str = NULL;
• char *stream_path;
• struct xen_front_cfg_stream *stream;
• int ret;
• stream_path = devm_kasprintf(&front_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;
  

Same as above.

will return PTR_ERR(str)

...

• 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;
  

• }

Until here this function looks very much like cfg_get_stream_type(). Can't they use a common sub-function?

Not really, because cfg_get_stream_type uses kasprintf for strings and this one devm_kasprintf. Trying to make a common sub-func doesn't make sense to me

...

• /* get next stream index */
• stream->index = (*stream_cnt)++;
• 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_read_pcm_hw(stream->xenstore_path,

• 	&pcm_instance->pcm_hw, &stream->pcm_hw);
  

• ret = 0;

+fail:

• kfree(str);
• return ret;

+}

+static int cfg_device(struct xen_snd_front_info *front_info,

•       struct xen_front_cfg_pcm_instance *pcm_instance,
  

•       struct snd_pcm_hardware *parent_pcm_hw,
  

•       const char *path, int node_index, int *stream_cnt)
  

+{

• 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_read_pcm_hw(device_path, parent_pcm_hw, &pcm_instance->pcm_hw);
• /* find out how many streams were configured in Xen store */
• 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(&front_info->xb_dev->dev,
  

• 			     pcm_instance->num_streams_pb,
  

• 			     sizeof(struct xen_front_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(&front_info->xb_dev->dev,
  

• 			     pcm_instance->num_streams_cap,
  

• 			     sizeof(struct xen_front_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(front_info, pcm_instance, device_path, i,
  

• 		 &cur_pb, &cur_cap, stream_cnt);
  

• if (ret < 0)
  

• 	goto fail;
  

• }
• ret = 0;

+fail:

• kfree(device_path);
• return ret;

+}

+int xen_snd_front_cfg_card(struct xen_snd_front_info *front_info,

• 	   int *stream_cnt)
  

+{

• struct xenbus_device *xb_dev = front_info->xb_dev;
• struct xen_front_cfg_card *cfg = &front_info->cfg;
• int ret, num_devices, i;
• char node[3];
• *stream_cnt = 0;
• 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_read_pcm_hw(xb_dev->nodename, NULL, &cfg->pcm_hw);
• cfg->pcm_instances =

• 	devm_kcalloc(&front_info->xb_dev->dev, num_devices,
  

• 		     sizeof(struct xen_front_cfg_pcm_instance),
  

• 		     GFP_KERNEL);
  

• if (!cfg->pcm_instances)

• return -ENOMEM;
  

• for (i = 0; i < num_devices; i++) {

• ret = cfg_device(front_info, &cfg->pcm_instances[i],
  

• 		 &cfg->pcm_hw, xb_dev->nodename, i, stream_cnt);
  

• if (ret < 0)
  

• 	return ret;
  

Who will free all the memory allocated until now in case of an error?

The memory is allocated with devm_xxx functions, so it will be freed on device destructions automatically

And I think when removing the device freeing the memory is missing, too.

Same as above, the kernel will take care of it while destroying the device

Juergen

On 04/16/2018 04:12 PM, Juergen Gross wrote:

On 16/04/18 08:24, Oleksandr Andrushchenko wrote:

...

From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

Handle Xen event channels:

• create for all configured streams and publish corresponding ring references and event channels in Xen store, so backend can connect
• implement event channels interrupt handlers
• create and destroy event channels with respect to Xen bus state

Signed-off-by: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

sound/xen/Makefile | 3 +- sound/xen/xen_snd_front.c | 10 +- sound/xen/xen_snd_front.h | 7 + sound/xen/xen_snd_front_evtchnl.c | 474 ++++++++++++++++++++++++++++++++++++++ sound/xen/xen_snd_front_evtchnl.h | 92 ++++++++ 5 files changed, 584 insertions(+), 2 deletions(-) create mode 100644 sound/xen/xen_snd_front_evtchnl.c create mode 100644 sound/xen/xen_snd_front_evtchnl.h

diff --git a/sound/xen/Makefile b/sound/xen/Makefile index 06705bef61fa..03c669984000 100644 --- a/sound/xen/Makefile +++ b/sound/xen/Makefile @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 OR MIT

snd_xen_front-objs := xen_snd_front.o \

•       xen_snd_front_cfg.o
  

•       xen_snd_front_cfg.o \
  

•       xen_snd_front_evtchnl.o
  
  

  obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o

diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c index 65d2494a9d14..eb46bf4070f9 100644 --- a/sound/xen/xen_snd_front.c +++ b/sound/xen/xen_snd_front.c @@ -18,9 +18,11 @@ #include <xen/interface/io/sndif.h>

#include "xen_snd_front.h" +#include "xen_snd_front_evtchnl.h"

Does it really make sense to have multiple driver-private headers?

I think those can be merged.

I would really like to keep it separate as it clearly shows which stuff belongs to which modules. At least for me it is easier to maintain it this way.

...

static void xen_snd_drv_fini(struct xen_snd_front_info *front_info) {

• xen_snd_front_evtchnl_free_all(front_info); }

  static int sndback_initwait(struct xen_snd_front_info *front_info)

@@ -32,7 +34,12 @@ static int sndback_initwait(struct xen_snd_front_info *front_info) if (ret < 0) return ret;

• return 0;

• /* create event channels for all streams and publish */

• ret = xen_snd_front_evtchnl_create_all(front_info, num_streams);

• if (ret < 0)

• return ret;
  

• return xen_snd_front_evtchnl_publish_all(front_info); }

  static int sndback_connect(struct xen_snd_front_info *front_info)

@@ -122,6 +129,7 @@ static int xen_drv_probe(struct xenbus_device *xb_dev, return -ENOMEM;

front_info->xb_dev = xb_dev;

• spin_lock_init(&front_info->io_lock); dev_set_drvdata(&xb_dev->dev, front_info);

  return xenbus_switch_state(xb_dev, XenbusStateInitialising);

diff --git a/sound/xen/xen_snd_front.h b/sound/xen/xen_snd_front.h index b52226cb30bc..9c2ffbb4e4b8 100644 --- a/sound/xen/xen_snd_front.h +++ b/sound/xen/xen_snd_front.h @@ -13,9 +13,16 @@

#include "xen_snd_front_cfg.h"

+struct xen_snd_front_evtchnl_pair;

• struct xen_snd_front_info { struct xenbus_device *xb_dev;

• /* serializer for backend IO: request/response */

• spinlock_t io_lock;

• int num_evt_pairs;

• struct xen_snd_front_evtchnl_pair *evt_pairs;

• struct xen_front_cfg_card cfg; };

diff --git a/sound/xen/xen_snd_front_evtchnl.c b/sound/xen/xen_snd_front_evtchnl.c new file mode 100644 index 000000000000..9ece39f938f8 --- /dev/null +++ b/sound/xen/xen_snd_front_evtchnl.c @@ -0,0 +1,474 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT

+/*

• • Xen para-virtual sound device
• • Copyright (C) 2016-2018 EPAM Systems Inc.
• • Author: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
• */

+#include <xen/events.h> +#include <xen/grant_table.h> +#include <xen/xen.h> +#include <xen/xenbus.h>

+#include "xen_snd_front.h" +#include "xen_snd_front_cfg.h" +#include "xen_snd_front_evtchnl.h"

+static irqreturn_t evtchnl_interrupt_req(int irq, void *dev_id) +{

• struct xen_snd_front_evtchnl *channel = dev_id;
• struct xen_snd_front_info *front_info = channel->front_info;
• struct xensnd_resp *resp;
• RING_IDX i, rp;
• unsigned long flags;
• if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))

• return IRQ_HANDLED;
  

• spin_lock_irqsave(&front_info->io_lock, flags);

+again:

• rp = channel->u.req.ring.sring->rsp_prod;
• /* ensure we see queued responses up to rp */
• rmb();
• for (i = channel->u.req.ring.rsp_cons; i != rp; i++) {

• resp = RING_GET_RESPONSE(&channel->u.req.ring, i);
  

• if (resp->id != channel->evt_id)
  

• 	continue;
  

• switch (resp->operation) {
  

• case XENSND_OP_OPEN:
  

• 	/* fall through */
  

• case XENSND_OP_CLOSE:
  

• 	/* fall through */
  

• case XENSND_OP_READ:
  

• 	/* fall through */
  

• case XENSND_OP_WRITE:
  

• 	/* fall through */
  

• case XENSND_OP_TRIGGER:
  

• 	channel->u.req.resp_status = resp->status;
  

• 	complete(&channel->u.req.completion);
  

• 	break;
  

• case XENSND_OP_HW_PARAM_QUERY:
  

• 	channel->u.req.resp_status = resp->status;
  

• 	channel->u.req.resp.hw_param =
  

• 			resp->resp.hw_param;
  

• 	complete(&channel->u.req.completion);
  

• 	break;
  

• default:
  

• 	dev_err(&front_info->xb_dev->dev,
  

• 		"Operation %d is not supported\n",
  

• 		resp->operation);
  

• 	break;
  

• }
  

• }
• channel->u.req.ring.rsp_cons = i;
• if (i != channel->u.req.ring.req_prod_pvt) {

• int more_to_do;
  

• RING_FINAL_CHECK_FOR_RESPONSES(&channel->u.req.ring,
  

• 			       more_to_do);
  

• if (more_to_do)
  

• 	goto again;
  

• } else {

• channel->u.req.ring.sring->rsp_event = i + 1;
  

• }
• spin_unlock_irqrestore(&front_info->io_lock, flags);
• return IRQ_HANDLED;

+}

+static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id) +{

• struct xen_snd_front_evtchnl *channel = dev_id;
• struct xen_snd_front_info *front_info = channel->front_info;
• struct xensnd_event_page *page = channel->u.evt.page;
• u32 cons, prod;
• unsigned long flags;
• if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))

• return IRQ_HANDLED;
  

• spin_lock_irqsave(&front_info->io_lock, flags);
• prod = page->in_prod;
• /* ensure we see ring contents up to prod */
• virt_rmb();
• if (prod == page->in_cons)

• goto out;
  

• for (cons = page->in_cons; cons != prod; cons++) {

• struct xensnd_evt *event;
  

• event = &XENSND_IN_RING_REF(page, cons);
  

• if (unlikely(event->id != channel->evt_id++))
  

• 	continue;
  

• switch (event->type) {
  

• case XENSND_EVT_CUR_POS:
  

• 	/* do nothing at the moment */
  

• 	break;
  

• }
  

• }
• page->in_cons = cons;
• /* ensure ring contents */
• virt_wmb();

+out:

• spin_unlock_irqrestore(&front_info->io_lock, flags);
• return IRQ_HANDLED;

+}

+void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *channel) +{

• int notify;
• channel->u.req.ring.req_prod_pvt++;
• RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&channel->u.req.ring, notify);
• if (notify)

• notify_remote_via_irq(channel->irq);
  

+}

+static void evtchnl_free(struct xen_snd_front_info *front_info,

• 	 struct xen_snd_front_evtchnl *channel)
  

+{

• unsigned long page = 0;
• if (channel->type == EVTCHNL_TYPE_REQ)

• page = (unsigned long)channel->u.req.ring.sring;
  

• else if (channel->type == EVTCHNL_TYPE_EVT)

• page = (unsigned long)channel->u.evt.page;
  

• if (!page)

• return;
  

• channel->state = EVTCHNL_STATE_DISCONNECTED;
• if (channel->type == EVTCHNL_TYPE_REQ) {

• /* release all who still waits for response if any */
  

• channel->u.req.resp_status = -EIO;
  

• complete_all(&channel->u.req.completion);
  

• }
• if (channel->irq)

• unbind_from_irqhandler(channel->irq, channel);
  

• if (channel->port)

• xenbus_free_evtchn(front_info->xb_dev, channel->port);
  

• /* end access and free the page */
• if (channel->gref != GRANT_INVALID_REF)

• gnttab_end_foreign_access(channel->gref, 0, page);
  

Free page?

According to [1] if page is provided to gnttab_end_foreign_access it will be freed. So, no need to free it manually

...

• memset(channel, 0, sizeof(*channel));

+}

+void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info) +{

• int i;
• if (!front_info->evt_pairs)

• return;
  

• for (i = 0; i < front_info->num_evt_pairs; i++) {

• evtchnl_free(front_info, &front_info->evt_pairs[i].req);
  

• evtchnl_free(front_info, &front_info->evt_pairs[i].evt);
  

• }
• kfree(front_info->evt_pairs);
• front_info->evt_pairs = NULL;

+}

+static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,

• 	 struct xen_snd_front_evtchnl *channel,
  

• 	 enum xen_snd_front_evtchnl_type type)
  

+{

• struct xenbus_device *xb_dev = front_info->xb_dev;
• unsigned long page;
• grant_ref_t gref;
• irq_handler_t handler;
• char *handler_name = NULL;
• int ret;
• memset(channel, 0, sizeof(*channel));
• channel->type = type;
• channel->index = index;
• channel->front_info = front_info;
• channel->state = EVTCHNL_STATE_DISCONNECTED;
• channel->gref = GRANT_INVALID_REF;
• page = get_zeroed_page(GFP_NOIO | __GFP_HIGH);

Why GFP_NOIO | __GFP_HIGH? Could it be you copied that from blkfront driver?

It can be net-front, I guess, which has the same for rx/tx rings

I believe swapping via sound card is rather uncommon.

Indeed, will use GFP_KERNEL here

...

• if (!page) {

• ret = -ENOMEM;
  

• goto fail;
  

• }
• handler_name = kasprintf(GFP_KERNEL, "%s-%s", XENSND_DRIVER_NAME,

• 		 type == EVTCHNL_TYPE_REQ ?
  

• 		 XENSND_FIELD_RING_REF :
  

• 		 XENSND_FIELD_EVT_RING_REF);
  

• if (!handler_name) {

• ret = -ENOMEM;
  

Missing free_page(page)? Maybe you rather add it in the common fail path instead of the numerous instances below?

yes, will move it under the common fail: label

Juergen

[1] https://elixir.bootlin.com/linux/v4.17-rc1/source/include/xen/grant_table.h#...

On 04/17/2018 02:14 PM, Juergen Gross wrote:

On 17/04/18 10:58, Oleksandr Andrushchenko wrote:

...

On 04/16/2018 04:12 PM, Juergen Gross wrote:

...

On 16/04/18 08:24, Oleksandr Andrushchenko wrote:

...

From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

Handle Xen event channels:    - create for all configured streams and publish      corresponding ring references and event channels in Xen store,      so backend can connect    - implement event channels interrupt handlers    - create and destroy event channels with respect to Xen bus state

Signed-off-by: Oleksandr Andrushchenko

oleksandr_andrushchenko@epam.com

sound/xen/Makefile                |   3 +-   sound/xen/xen_snd_front.c         |  10 +-   sound/xen/xen_snd_front.h         |   7 +   sound/xen/xen_snd_front_evtchnl.c | 474 ++++++++++++++++++++++++++++++++++++++   sound/xen/xen_snd_front_evtchnl.h |  92 ++++++++   5 files changed, 584 insertions(+), 2 deletions(-)   create mode 100644 sound/xen/xen_snd_front_evtchnl.c   create mode 100644 sound/xen/xen_snd_front_evtchnl.h

diff --git a/sound/xen/Makefile b/sound/xen/Makefile index 06705bef61fa..03c669984000 100644 --- a/sound/xen/Makefile +++ b/sound/xen/Makefile @@ -1,6 +1,7 @@   # SPDX-License-Identifier: GPL-2.0 OR MIT     snd_xen_front-objs := xen_snd_front.o \ -              xen_snd_front_cfg.o +              xen_snd_front_cfg.o \ +              xen_snd_front_evtchnl.o     obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c index 65d2494a9d14..eb46bf4070f9 100644 --- a/sound/xen/xen_snd_front.c +++ b/sound/xen/xen_snd_front.c @@ -18,9 +18,11 @@   #include <xen/interface/io/sndif.h>     #include "xen_snd_front.h" +#include "xen_snd_front_evtchnl.h"

Does it really make sense to have multiple driver-private headers?

I think those can be merged.

I would really like to keep it separate as it clearly shows which stuff belongs to which modules. At least for me it is easier to maintain it this way.

...

...

static void xen_snd_drv_fini(struct xen_snd_front_info *front_info)   { +    xen_snd_front_evtchnl_free_all(front_info);   }     static int sndback_initwait(struct xen_snd_front_info *front_info) @@ -32,7 +34,12 @@ static int sndback_initwait(struct xen_snd_front_info *front_info)       if (ret < 0)           return ret;   -    return 0; +    /* create event channels for all streams and publish */ +    ret = xen_snd_front_evtchnl_create_all(front_info, num_streams); +    if (ret < 0) +        return ret;

+    return xen_snd_front_evtchnl_publish_all(front_info);   }     static int sndback_connect(struct xen_snd_front_info *front_info) @@ -122,6 +129,7 @@ static int xen_drv_probe(struct xenbus_device *xb_dev,           return -ENOMEM;         front_info->xb_dev = xb_dev; +    spin_lock_init(&front_info->io_lock);       dev_set_drvdata(&xb_dev->dev, front_info);         return xenbus_switch_state(xb_dev, XenbusStateInitialising); diff --git a/sound/xen/xen_snd_front.h b/sound/xen/xen_snd_front.h index b52226cb30bc..9c2ffbb4e4b8 100644 --- a/sound/xen/xen_snd_front.h +++ b/sound/xen/xen_snd_front.h @@ -13,9 +13,16 @@     #include "xen_snd_front_cfg.h"   +struct xen_snd_front_evtchnl_pair;

struct xen_snd_front_info {       struct xenbus_device *xb_dev;   +    /* serializer for backend IO: request/response */ +    spinlock_t io_lock; +    int num_evt_pairs; +    struct xen_snd_front_evtchnl_pair *evt_pairs;

struct xen_front_cfg_card cfg;   };   diff --git a/sound/xen/xen_snd_front_evtchnl.c b/sound/xen/xen_snd_front_evtchnl.c new file mode 100644 index 000000000000..9ece39f938f8 --- /dev/null +++ b/sound/xen/xen_snd_front_evtchnl.c @@ -0,0 +1,474 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT

+/*

• • Xen para-virtual sound device
• • Copyright (C) 2016-2018 EPAM Systems Inc.
• • Author: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
• */

+#include <xen/events.h> +#include <xen/grant_table.h> +#include <xen/xen.h> +#include <xen/xenbus.h>

+#include "xen_snd_front.h" +#include "xen_snd_front_cfg.h" +#include "xen_snd_front_evtchnl.h"

+static irqreturn_t evtchnl_interrupt_req(int irq, void *dev_id) +{ +    struct xen_snd_front_evtchnl *channel = dev_id; +    struct xen_snd_front_info *front_info = channel->front_info; +    struct xensnd_resp *resp; +    RING_IDX i, rp; +    unsigned long flags;

+    if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED)) +        return IRQ_HANDLED;

+    spin_lock_irqsave(&front_info->io_lock, flags);

+again: +    rp = channel->u.req.ring.sring->rsp_prod; +    /* ensure we see queued responses up to rp */ +    rmb();

+    for (i = channel->u.req.ring.rsp_cons; i != rp; i++) { +        resp = RING_GET_RESPONSE(&channel->u.req.ring, i); +        if (resp->id != channel->evt_id) +            continue; +        switch (resp->operation) { +        case XENSND_OP_OPEN: +            /* fall through */ +        case XENSND_OP_CLOSE: +            /* fall through */ +        case XENSND_OP_READ: +            /* fall through */ +        case XENSND_OP_WRITE: +            /* fall through */ +        case XENSND_OP_TRIGGER: +            channel->u.req.resp_status = resp->status; +            complete(&channel->u.req.completion); +            break; +        case XENSND_OP_HW_PARAM_QUERY: +            channel->u.req.resp_status = resp->status; +            channel->u.req.resp.hw_param = +                    resp->resp.hw_param; +            complete(&channel->u.req.completion); +            break;

+        default: +            dev_err(&front_info->xb_dev->dev, +                "Operation %d is not supported\n", +                resp->operation); +            break; +        } +    }

+    channel->u.req.ring.rsp_cons = i; +    if (i != channel->u.req.ring.req_prod_pvt) { +        int more_to_do;

+        RING_FINAL_CHECK_FOR_RESPONSES(&channel->u.req.ring, +                           more_to_do); +        if (more_to_do) +            goto again; +    } else { +        channel->u.req.ring.sring->rsp_event = i + 1; +    }

+    spin_unlock_irqrestore(&front_info->io_lock, flags); +    return IRQ_HANDLED; +}

+static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id) +{ +    struct xen_snd_front_evtchnl *channel = dev_id; +    struct xen_snd_front_info *front_info = channel->front_info; +    struct xensnd_event_page *page = channel->u.evt.page; +    u32 cons, prod; +    unsigned long flags;

+    if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED)) +        return IRQ_HANDLED;

+    spin_lock_irqsave(&front_info->io_lock, flags);

+    prod = page->in_prod; +    /* ensure we see ring contents up to prod */ +    virt_rmb(); +    if (prod == page->in_cons) +        goto out;

+    for (cons = page->in_cons; cons != prod; cons++) { +        struct xensnd_evt *event;

+        event = &XENSND_IN_RING_REF(page, cons); +        if (unlikely(event->id != channel->evt_id++)) +            continue;

+        switch (event->type) { +        case XENSND_EVT_CUR_POS: +            /* do nothing at the moment */ +            break; +        } +    }

+    page->in_cons = cons; +    /* ensure ring contents */ +    virt_wmb();

+out: +    spin_unlock_irqrestore(&front_info->io_lock, flags); +    return IRQ_HANDLED; +}

+void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *channel) +{ +    int notify;

+    channel->u.req.ring.req_prod_pvt++; +    RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&channel->u.req.ring, notify); +    if (notify) +        notify_remote_via_irq(channel->irq); +}

+static void evtchnl_free(struct xen_snd_front_info *front_info, +             struct xen_snd_front_evtchnl *channel) +{ +    unsigned long page = 0;

+    if (channel->type == EVTCHNL_TYPE_REQ) +        page = (unsigned long)channel->u.req.ring.sring; +    else if (channel->type == EVTCHNL_TYPE_EVT) +        page = (unsigned long)channel->u.evt.page;

+    if (!page) +        return;

+    channel->state = EVTCHNL_STATE_DISCONNECTED; +    if (channel->type == EVTCHNL_TYPE_REQ) { +        /* release all who still waits for response if any */ +        channel->u.req.resp_status = -EIO; +        complete_all(&channel->u.req.completion); +    }

+    if (channel->irq) +        unbind_from_irqhandler(channel->irq, channel);

+    if (channel->port) +        xenbus_free_evtchn(front_info->xb_dev, channel->port);

+    /* end access and free the page */ +    if (channel->gref != GRANT_INVALID_REF) +        gnttab_end_foreign_access(channel->gref, 0, page);

Free page?

According to [1] if page is provided to gnttab_end_foreign_access it will be freed. So, no need to free it manually

Either a free_page() is missing here in an else clause or the if is not necessary.

Good catch ;) I need else + free_page, because I won't be able to end access for invalid grant ref. Thank you

Juergen

On 16/04/18 08:24, Oleksandr Andrushchenko wrote:

From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

Implement shared buffer handling according to the para-virtualized sound device protocol at xen/interface/io/sndif.h:

• manage buffer memory
• handle granted references
• handle page directories

Signed-off-by: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

sound/xen/Makefile | 3 +- sound/xen/xen_snd_front.c | 8 ++ sound/xen/xen_snd_front_shbuf.c | 193 ++++++++++++++++++++++++++++++++++++++++ sound/xen/xen_snd_front_shbuf.h | 36 ++++++++ 4 files changed, 239 insertions(+), 1 deletion(-) create mode 100644 sound/xen/xen_snd_front_shbuf.c create mode 100644 sound/xen/xen_snd_front_shbuf.h

diff --git a/sound/xen/Makefile b/sound/xen/Makefile index 03c669984000..f028bc30af5d 100644 --- a/sound/xen/Makefile +++ b/sound/xen/Makefile @@ -2,6 +2,7 @@

snd_xen_front-objs := xen_snd_front.o \ xen_snd_front_cfg.o \

•       xen_snd_front_evtchnl.o
  

•       xen_snd_front_evtchnl.o \
  

•       xen_snd_front_shbuf.o
  
  

obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c index eb46bf4070f9..0569c6c596a3 100644 --- a/sound/xen/xen_snd_front.c +++ b/sound/xen/xen_snd_front.c @@ -11,6 +11,7 @@ #include <linux/delay.h> #include <linux/module.h>

+#include <xen/page.h> #include <xen/platform_pci.h> #include <xen/xen.h> #include <xen/xenbus.h> @@ -186,6 +187,13 @@ static struct xenbus_driver xen_driver = {

static int __init xen_drv_init(void) {

• /* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */
• if (XEN_PAGE_SIZE != PAGE_SIZE) {

• pr_err(XENSND_DRIVER_NAME ": different kernel and Xen page sizes are not supported: XEN_PAGE_SIZE (%lu) != PAGE_SIZE (%lu)\n",
  

•        XEN_PAGE_SIZE, PAGE_SIZE);
  

• return -ENODEV;
  

• }

Do you really want to print that error message on bare metal?

• if (!xen_domain()) return -ENODEV;

diff --git a/sound/xen/xen_snd_front_shbuf.c b/sound/xen/xen_snd_front_shbuf.c new file mode 100644 index 000000000000..6845dbc7fdf5 --- /dev/null +++ b/sound/xen/xen_snd_front_shbuf.c @@ -0,0 +1,193 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT

+/*

• • Xen para-virtual sound device
• • Copyright (C) 2016-2018 EPAM Systems Inc.
• • Author: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
• */

+#include <xen/xen.h> +#include <xen/xenbus.h>

+#include "xen_snd_front_shbuf.h"

+grant_ref_t xen_snd_front_shbuf_get_dir_start(struct xen_snd_front_shbuf *buf) +{

• if (!buf->grefs)

• return GRANT_INVALID_REF;
  

• return buf->grefs[0];

+}

+void xen_snd_front_shbuf_clear(struct xen_snd_front_shbuf *buf) +{

• memset(buf, 0, sizeof(*buf));

+}

+void xen_snd_front_shbuf_free(struct xen_snd_front_shbuf *buf) +{

• int i;
• if (buf->grefs) {

• for (i = 0; i < buf->num_grefs; i++)
  

• 	if (buf->grefs[i] != GRANT_INVALID_REF)
  

• 		gnttab_end_foreign_access(buf->grefs[i],
  

• 					  0, 0UL);
  

• kfree(buf->grefs);
  

• }
• kfree(buf->directory);
• free_pages_exact(buf->buffer, buf->buffer_sz);
• xen_snd_front_shbuf_clear(buf);

+}

+/*

• • number of grant references a page can hold with respect to the
• • xensnd_page_directory header
• */

+#define XENSND_NUM_GREFS_PER_PAGE ((XEN_PAGE_SIZE - \

• offsetof(struct xensnd_page_directory, gref)) / \
  

• sizeof(grant_ref_t))
  

+static void fill_page_dir(struct xen_snd_front_shbuf *buf,

• 	  int num_pages_dir)
  

+{

• struct xensnd_page_directory *page_dir;
• unsigned char *ptr;
• int i, cur_gref, grefs_left, to_copy;
• ptr = buf->directory;
• grefs_left = buf->num_grefs - num_pages_dir;
• /*

• * skip grant references at the beginning, they are for pages granted
  

• * for the page directory itself
  

• */
  

• cur_gref = num_pages_dir;
• for (i = 0; i < num_pages_dir; i++) {

• page_dir = (struct xensnd_page_directory *)ptr;
  

• if (grefs_left <= XENSND_NUM_GREFS_PER_PAGE) {
  

• 	to_copy = grefs_left;
  

• 	page_dir->gref_dir_next_page = GRANT_INVALID_REF;
  

• } else {
  

• 	to_copy = XENSND_NUM_GREFS_PER_PAGE;
  

• 	page_dir->gref_dir_next_page = buf->grefs[i + 1];
  

• }
  

• memcpy(&page_dir->gref, &buf->grefs[cur_gref],
  

•        to_copy * sizeof(grant_ref_t));
  

• ptr += XEN_PAGE_SIZE;
  

• grefs_left -= to_copy;
  

• cur_gref += to_copy;
  

• }

+}

+static int grant_references(struct xenbus_device *xb_dev,

• 	    struct xen_snd_front_shbuf *buf,
  

• 	    int num_pages_dir, int num_pages_buffer,
  

• 	    int num_grefs)
  

+{

• grant_ref_t priv_gref_head;
• unsigned long frame;
• int ret, i, j, cur_ref;
• int otherend_id;
• ret = gnttab_alloc_grant_references(num_grefs, &priv_gref_head);
• if (ret)

• return ret;
  

• buf->num_grefs = num_grefs;
• otherend_id = xb_dev->otherend_id;
• j = 0;
• for (i = 0; i < num_pages_dir; i++) {

• cur_ref = gnttab_claim_grant_reference(&priv_gref_head);
  

• if (cur_ref < 0) {
  

• 	ret = cur_ref;
  

• 	goto fail;
  

• }
  

• frame = xen_page_to_gfn(virt_to_page(buf->directory +
  

• 				     XEN_PAGE_SIZE * i));
  

• gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 0);
  

• buf->grefs[j++] = cur_ref;
  

• }
• for (i = 0; i < num_pages_buffer; i++) {

• cur_ref = gnttab_claim_grant_reference(&priv_gref_head);
  

• if (cur_ref < 0) {
  

• 	ret = cur_ref;
  

• 	goto fail;
  

• }
  

• frame = xen_page_to_gfn(virt_to_page(buf->buffer +
  

• 				     XEN_PAGE_SIZE * i));
  

• gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 0);
  

• buf->grefs[j++] = cur_ref;
  

• }
• gnttab_free_grant_references(priv_gref_head);
• fill_page_dir(buf, num_pages_dir);
• return 0;

+fail:

• gnttab_free_grant_references(priv_gref_head);
• return ret;

+}

+static int alloc_int_buffers(struct xen_snd_front_shbuf *buf,

• 	     int num_pages_dir, int num_pages_buffer,
  

• 	     int num_grefs)
  

+{

• buf->grefs = kcalloc(num_grefs, sizeof(*buf->grefs), GFP_KERNEL);
• if (!buf->grefs)

• return -ENOMEM;
  

• buf->directory = kcalloc(num_pages_dir, XEN_PAGE_SIZE, GFP_KERNEL);
• if (!buf->directory)

• goto fail;
  

• buf->buffer_sz = num_pages_buffer * XEN_PAGE_SIZE;
• buf->buffer = alloc_pages_exact(buf->buffer_sz, GFP_KERNEL);
• if (!buf->buffer)

• goto fail;
  

• return 0;

+fail:

• kfree(buf->grefs);
• buf->grefs = NULL;
• kfree(buf->directory);

Why do you need to free those here? Shouldn't that be done via xen_snd_front_shbuf_free() in case of an error?

Juergen

On 16/04/18 08:24, Oleksandr Andrushchenko wrote:

From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

Implement essential initialization of the sound driver:

• introduce required data structures
• handle driver registration
• handle sound card registration
• register sound driver on backend connection
• remove sound driver on backend disconnect

Initialize virtual sound card with streams according to the Xen store configuration.

Implement ALSA driver operations including:

• manage frontend/backend shared buffers
• manage Xen bus event channel states

Implement requests from front to back for ALSA PCM operations.

• report ALSA period elapsed event: handle XENSND_EVT_CUR_POS notifications from the backend when stream position advances during playback/capture. The event carries a value of how many octets were played/captured at the time of the event.
• implement explicit stream parameter negotiation between backend and frontend: handle XENSND_OP_HW_PARAM_QUERY request to read/update configuration space for the parameter given: request passes desired parameter interval and the response to this request returns min/max interval for the parameter to be used.

Signed-off-by: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com

sound/xen/Makefile | 3 +- sound/xen/xen_snd_front.c | 193 ++++++++- sound/xen/xen_snd_front.h | 28 ++ sound/xen/xen_snd_front_alsa.c | 830 ++++++++++++++++++++++++++++++++++++++ sound/xen/xen_snd_front_alsa.h | 23 ++ sound/xen/xen_snd_front_evtchnl.c | 6 +- 6 files changed, 1080 insertions(+), 3 deletions(-) create mode 100644 sound/xen/xen_snd_front_alsa.c create mode 100644 sound/xen/xen_snd_front_alsa.h

diff --git a/sound/xen/Makefile b/sound/xen/Makefile index f028bc30af5d..1e6470ecc2f2 100644 --- a/sound/xen/Makefile +++ b/sound/xen/Makefile @@ -3,6 +3,7 @@ snd_xen_front-objs := xen_snd_front.o \ xen_snd_front_cfg.o \ xen_snd_front_evtchnl.o \

•       xen_snd_front_shbuf.o
  

•       xen_snd_front_shbuf.o \
  

•       xen_snd_front_alsa.o
  
  

obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c index 0569c6c596a3..1fef253ea21a 100644 --- a/sound/xen/xen_snd_front.c +++ b/sound/xen/xen_snd_front.c @@ -19,10 +19,201 @@ #include <xen/interface/io/sndif.h>

#include "xen_snd_front.h" +#include "xen_snd_front_alsa.h" #include "xen_snd_front_evtchnl.h" +#include "xen_snd_front_shbuf.h"

+static struct xensnd_req * +be_stream_prepare_req(struct xen_snd_front_evtchnl *evtchnl, u8 operation) +{

• struct xensnd_req *req;
• req = RING_GET_REQUEST(&evtchnl->u.req.ring,

• 	       evtchnl->u.req.ring.req_prod_pvt);
  

• req->operation = operation;
• req->id = evtchnl->evt_next_id++;
• evtchnl->evt_id = req->id;
• return req;

+}

+static int be_stream_do_io(struct xen_snd_front_evtchnl *evtchnl) +{

• if (unlikely(evtchnl->state != EVTCHNL_STATE_CONNECTED))

• return -EIO;
  

• reinit_completion(&evtchnl->u.req.completion);
• xen_snd_front_evtchnl_flush(evtchnl);
• return 0;

+}

+static int be_stream_wait_io(struct xen_snd_front_evtchnl *evtchnl) +{

• if (wait_for_completion_timeout(&evtchnl->u.req.completion,

• 	msecs_to_jiffies(VSND_WAIT_BACK_MS)) <= 0)
  

• return -ETIMEDOUT;
  

• return evtchnl->u.req.resp_status;

+}

+int xen_snd_front_stream_query_hw_param(struct xen_snd_front_evtchnl *evtchnl,

• 			struct xensnd_query_hw_param *hw_param_req,
  

• 			struct xensnd_query_hw_param *hw_param_resp)
  

+{

• struct xen_snd_front_info *front_info = evtchnl->front_info;
• struct xensnd_req *req;
• unsigned long flags;
• int ret;
• mutex_lock(&evtchnl->u.req.req_io_lock);
• spin_lock_irqsave(&front_info->io_lock, flags);
• req = be_stream_prepare_req(evtchnl, XENSND_OP_HW_PARAM_QUERY);
• req->op.hw_param = *hw_param_req;
• ret = be_stream_do_io(evtchnl);
• spin_unlock_irqrestore(&front_info->io_lock, flags);
• if (ret == 0)

• ret = be_stream_wait_io(evtchnl);
  

• if (ret == 0)

• *hw_param_resp = evtchnl->u.req.resp.hw_param;
  

• mutex_unlock(&evtchnl->u.req.req_io_lock);
• return ret;

+}

+int xen_snd_front_stream_prepare(struct xen_snd_front_evtchnl *evtchnl,

• 		 struct xen_snd_front_shbuf *sh_buf,
  

• 		 u8 format, unsigned int channels,
  

• 		 unsigned int rate, u32 buffer_sz,
  

• 		 u32 period_sz)
  

+{

• struct xen_snd_front_info *front_info = evtchnl->front_info;
• struct xensnd_req *req;
• unsigned long flags;
• int ret;
• mutex_lock(&evtchnl->u.req.req_io_lock);
• spin_lock_irqsave(&front_info->io_lock, flags);
• req = be_stream_prepare_req(evtchnl, XENSND_OP_OPEN);
• req->op.open.pcm_format = format;
• req->op.open.pcm_channels = channels;
• req->op.open.pcm_rate = rate;
• req->op.open.buffer_sz = buffer_sz;
• req->op.open.period_sz = period_sz;
• req->op.open.gref_directory = xen_snd_front_shbuf_get_dir_start(sh_buf);
• ret = be_stream_do_io(evtchnl);
• spin_unlock_irqrestore(&front_info->io_lock, flags);
• if (ret == 0)

• ret = be_stream_wait_io(evtchnl);
  

• mutex_unlock(&evtchnl->u.req.req_io_lock);
• return ret;

+}

+int xen_snd_front_stream_close(struct xen_snd_front_evtchnl *evtchnl) +{

• struct xen_snd_front_info *front_info = evtchnl->front_info;
• struct xensnd_req *req;
• unsigned long flags;
• int ret;
• mutex_lock(&evtchnl->u.req.req_io_lock);
• spin_lock_irqsave(&front_info->io_lock, flags);
• req = be_stream_prepare_req(evtchnl, XENSND_OP_CLOSE);
• ret = be_stream_do_io(evtchnl);
• spin_unlock_irqrestore(&front_info->io_lock, flags);
• if (ret == 0)

• ret = be_stream_wait_io(evtchnl);
  

• mutex_unlock(&evtchnl->u.req.req_io_lock);
• return ret;

+}

+int xen_snd_front_stream_write(struct xen_snd_front_evtchnl *evtchnl,

• 	       unsigned long pos, unsigned long count)
  

+{

• struct xen_snd_front_info *front_info = evtchnl->front_info;
• struct xensnd_req *req;
• unsigned long flags;
• int ret;
• mutex_lock(&evtchnl->u.req.req_io_lock);
• spin_lock_irqsave(&front_info->io_lock, flags);
• req = be_stream_prepare_req(evtchnl, XENSND_OP_WRITE);
• req->op.rw.length = count;
• req->op.rw.offset = pos;
• ret = be_stream_do_io(evtchnl);
• spin_unlock_irqrestore(&front_info->io_lock, flags);
• if (ret == 0)

• ret = be_stream_wait_io(evtchnl);
  

• mutex_unlock(&evtchnl->u.req.req_io_lock);
• return ret;

+}

+int xen_snd_front_stream_read(struct xen_snd_front_evtchnl *evtchnl,

• 	      unsigned long pos, unsigned long count)
  

+{

• struct xen_snd_front_info *front_info = evtchnl->front_info;
• struct xensnd_req *req;
• unsigned long flags;
• int ret;
• mutex_lock(&evtchnl->u.req.req_io_lock);
• spin_lock_irqsave(&front_info->io_lock, flags);
• req = be_stream_prepare_req(evtchnl, XENSND_OP_READ);
• req->op.rw.length = count;
• req->op.rw.offset = pos;
• ret = be_stream_do_io(evtchnl);
• spin_unlock_irqrestore(&front_info->io_lock, flags);
• if (ret == 0)

• ret = be_stream_wait_io(evtchnl);
  

• mutex_unlock(&evtchnl->u.req.req_io_lock);
• return ret;

+}

+int xen_snd_front_stream_trigger(struct xen_snd_front_evtchnl *evtchnl,

• 		 int type)
  

+{

• struct xen_snd_front_info *front_info = evtchnl->front_info;
• struct xensnd_req *req;
• unsigned long flags;
• int ret;
• mutex_lock(&evtchnl->u.req.req_io_lock);
• spin_lock_irqsave(&front_info->io_lock, flags);
• req = be_stream_prepare_req(evtchnl, XENSND_OP_TRIGGER);
• req->op.trigger.type = type;
• ret = be_stream_do_io(evtchnl);
• spin_unlock_irqrestore(&front_info->io_lock, flags);
• if (ret == 0)

• ret = be_stream_wait_io(evtchnl);
  

• mutex_unlock(&evtchnl->u.req.req_io_lock);
• return ret;

+}

static void xen_snd_drv_fini(struct xen_snd_front_info *front_info) {

• xen_snd_front_alsa_fini(front_info); xen_snd_front_evtchnl_free_all(front_info);

}

@@ -45,7 +236,7 @@ static int sndback_initwait(struct xen_snd_front_info *front_info)

static int sndback_connect(struct xen_snd_front_info *front_info) {

• return 0;

• return xen_snd_front_alsa_init(front_info);

}

static void sndback_disconnect(struct xen_snd_front_info *front_info) diff --git a/sound/xen/xen_snd_front.h b/sound/xen/xen_snd_front.h index 9c2ffbb4e4b8..7adbdb4d2019 100644 --- a/sound/xen/xen_snd_front.h +++ b/sound/xen/xen_snd_front.h @@ -13,17 +13,45 @@

#include "xen_snd_front_cfg.h"

+struct card_info; +struct xen_snd_front_evtchnl; struct xen_snd_front_evtchnl_pair; +struct xen_snd_front_shbuf; +struct xensnd_query_hw_param;

struct xen_snd_front_info { struct xenbus_device *xb_dev;

• struct card_info *card_info;

• /* serializer for backend IO: request/response */ spinlock_t io_lock;

• int num_evt_pairs; struct xen_snd_front_evtchnl_pair *evt_pairs;

  struct xen_front_cfg_card cfg;

};

+int xen_snd_front_stream_query_hw_param(struct xen_snd_front_evtchnl *evtchnl,

• 			struct xensnd_query_hw_param *hw_param_req,
  

• 			struct xensnd_query_hw_param *hw_param_resp);
  

+int xen_snd_front_stream_prepare(struct xen_snd_front_evtchnl *evtchnl,

• 		 struct xen_snd_front_shbuf *sh_buf,
  

• 		 u8 format, unsigned int channels,
  

• 		 unsigned int rate, u32 buffer_sz,
  

• 		 u32 period_sz);
  

+int xen_snd_front_stream_close(struct xen_snd_front_evtchnl *evtchnl);

+int xen_snd_front_stream_write(struct xen_snd_front_evtchnl *evtchnl,

• 	       unsigned long pos, unsigned long count);
  

+int xen_snd_front_stream_read(struct xen_snd_front_evtchnl *evtchnl,

• 	      unsigned long pos, unsigned long count);
  

+int xen_snd_front_stream_trigger(struct xen_snd_front_evtchnl *evtchnl,

• 		 int type);
  

#endif /* __XEN_SND_FRONT_H */ diff --git a/sound/xen/xen_snd_front_alsa.c b/sound/xen/xen_snd_front_alsa.c new file mode 100644 index 000000000000..f524b172750e --- /dev/null +++ b/sound/xen/xen_snd_front_alsa.c @@ -0,0 +1,830 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT

+/*

• • Xen para-virtual sound device
• • Copyright (C) 2016-2018 EPAM Systems Inc.
• • Author: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
• */

+#include <linux/platform_device.h>

+#include <sound/core.h> +#include <sound/pcm.h> +#include <sound/pcm_params.h>

+#include <xen/xenbus.h>

+#include "xen_snd_front.h" +#include "xen_snd_front_alsa.h" +#include "xen_snd_front_cfg.h" +#include "xen_snd_front_evtchnl.h" +#include "xen_snd_front_shbuf.h"

+struct pcm_stream_info {

Not sure how this is generally handled in the sound drivers, but when reviewing the code using those structures I repeatedly tried to find their definitions in the sound headers instead of here. Same applies to the alsa_* names.

I'd prefer names which don't poison the name space.

• struct xen_snd_front_info *front_info;
• struct xen_snd_front_evtchnl_pair *evt_pair;
• struct xen_snd_front_shbuf sh_buf;
• int index;
• bool is_open;
• struct snd_pcm_hardware pcm_hw;
• /* number of processed frames as reported by the backend */
• snd_pcm_uframes_t be_cur_frame;
• /* current HW pointer to be reported via .period callback */
• atomic_t hw_ptr;
• /* modulo of the number of processed frames - for period detection */
• u32 out_frames;

+};

+struct pcm_instance_info {

• struct card_info *card_info;
• struct snd_pcm *pcm;
• struct snd_pcm_hardware pcm_hw;
• int num_pcm_streams_pb;
• struct pcm_stream_info *streams_pb;
• int num_pcm_streams_cap;
• struct pcm_stream_info *streams_cap;

+};

+struct card_info {

• struct xen_snd_front_info *front_info;
• struct snd_card *card;
• struct snd_pcm_hardware pcm_hw;
• int num_pcm_instances;
• struct pcm_instance_info *pcm_instances;

+};

+struct alsa_sndif_sample_format {

• u8 sndif;
• snd_pcm_format_t alsa;

+};

+struct alsa_sndif_hw_param {

• u8 sndif;
• snd_pcm_hw_param_t alsa;

+};

+static const struct alsa_sndif_sample_format ALSA_SNDIF_FORMATS[] = {

• {

• .sndif = XENSND_PCM_FORMAT_U8,
  

• .alsa = SNDRV_PCM_FORMAT_U8
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_S8,
  

• .alsa = SNDRV_PCM_FORMAT_S8
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_U16_LE,
  

• .alsa = SNDRV_PCM_FORMAT_U16_LE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_U16_BE,
  

• .alsa = SNDRV_PCM_FORMAT_U16_BE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_S16_LE,
  

• .alsa = SNDRV_PCM_FORMAT_S16_LE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_S16_BE,
  

• .alsa = SNDRV_PCM_FORMAT_S16_BE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_U24_LE,
  

• .alsa = SNDRV_PCM_FORMAT_U24_LE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_U24_BE,
  

• .alsa = SNDRV_PCM_FORMAT_U24_BE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_S24_LE,
  

• .alsa = SNDRV_PCM_FORMAT_S24_LE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_S24_BE,
  

• .alsa = SNDRV_PCM_FORMAT_S24_BE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_U32_LE,
  

• .alsa = SNDRV_PCM_FORMAT_U32_LE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_U32_BE,
  

• .alsa = SNDRV_PCM_FORMAT_U32_BE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_S32_LE,
  

• .alsa = SNDRV_PCM_FORMAT_S32_LE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_S32_BE,
  

• .alsa = SNDRV_PCM_FORMAT_S32_BE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_A_LAW,
  

• .alsa = SNDRV_PCM_FORMAT_A_LAW
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_MU_LAW,
  

• .alsa = SNDRV_PCM_FORMAT_MU_LAW
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_F32_LE,
  

• .alsa = SNDRV_PCM_FORMAT_FLOAT_LE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_F32_BE,
  

• .alsa = SNDRV_PCM_FORMAT_FLOAT_BE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_F64_LE,
  

• .alsa = SNDRV_PCM_FORMAT_FLOAT64_LE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_F64_BE,
  

• .alsa = SNDRV_PCM_FORMAT_FLOAT64_BE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_IEC958_SUBFRAME_LE,
  

• .alsa = SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_IEC958_SUBFRAME_BE,
  

• .alsa = SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_IMA_ADPCM,
  

• .alsa = SNDRV_PCM_FORMAT_IMA_ADPCM
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_MPEG,
  

• .alsa = SNDRV_PCM_FORMAT_MPEG
  

• },
• {

• .sndif = XENSND_PCM_FORMAT_GSM,
  

• .alsa = SNDRV_PCM_FORMAT_GSM
  

• },

+};

+static int to_sndif_format(snd_pcm_format_t format) +{

• int i;
• for (i = 0; i < ARRAY_SIZE(ALSA_SNDIF_FORMATS); i++)

• if (ALSA_SNDIF_FORMATS[i].alsa == format)
  

• 	return ALSA_SNDIF_FORMATS[i].sndif;
  

• return -EINVAL;

+}

+static u64 to_sndif_formats_mask(u64 alsa_formats) +{

• u64 mask;
• int i;
• mask = 0;
• for (i = 0; i < ARRAY_SIZE(ALSA_SNDIF_FORMATS); i++)

• if (1 << ALSA_SNDIF_FORMATS[i].alsa & alsa_formats)
  

• 	mask |= 1 << ALSA_SNDIF_FORMATS[i].sndif;
  

• return mask;

+}

+static u64 to_alsa_formats_mask(u64 sndif_formats) +{

• u64 mask;
• int i;
• mask = 0;
• for (i = 0; i < ARRAY_SIZE(ALSA_SNDIF_FORMATS); i++)

• if (1 << ALSA_SNDIF_FORMATS[i].sndif & sndif_formats)
  

• 	mask |= 1 << ALSA_SNDIF_FORMATS[i].alsa;
  

• return mask;

+}

+static void stream_clear(struct pcm_stream_info *stream) +{

• stream->is_open = false;
• stream->be_cur_frame = 0;
• stream->out_frames = 0;
• atomic_set(&stream->hw_ptr, 0);
• xen_snd_front_evtchnl_pair_clear(stream->evt_pair);
• xen_snd_front_shbuf_clear(&stream->sh_buf);

+}

+static void stream_free(struct pcm_stream_info *stream) +{

• xen_snd_front_shbuf_free(&stream->sh_buf);
• stream_clear(stream);

+}

+static struct pcm_stream_info *stream_get(struct snd_pcm_substream *substream) +{

• struct pcm_instance_info *pcm_instance =

• 	snd_pcm_substream_chip(substream);
  

• struct pcm_stream_info *stream;
• if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)

• stream = &pcm_instance->streams_pb[substream->number];
  

• else

• stream = &pcm_instance->streams_cap[substream->number];
  

• return stream;

+}

+static int alsa_hw_rule(struct snd_pcm_hw_params *params,

• 	struct snd_pcm_hw_rule *rule)
  

+{

• struct pcm_stream_info *stream = rule->private;
• struct device *dev = &stream->front_info->xb_dev->dev;
• struct snd_mask *formats =

• 	hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
  

• struct snd_interval *rates =

• 	hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
  

• struct snd_interval *channels =

• 	hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
  

• struct snd_interval *period =

• 	hw_param_interval(params,
  

• 			  SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
  

• struct snd_interval *buffer =

• 	hw_param_interval(params,
  

• 			  SNDRV_PCM_HW_PARAM_BUFFER_SIZE);
  

• struct xensnd_query_hw_param req;
• struct xensnd_query_hw_param resp;
• struct snd_interval interval;
• struct snd_mask mask;
• u64 sndif_formats;
• int changed, ret;
• /* collect all the values we need for the query */
• req.formats = to_sndif_formats_mask((u64)formats->bits[0] |

• 			    (u64)(formats->bits[1]) << 32);
  

• req.rates.min = rates->min;
• req.rates.max = rates->max;
• req.channels.min = channels->min;
• req.channels.max = channels->max;
• req.buffer.min = buffer->min;
• req.buffer.max = buffer->max;
• req.period.min = period->min;
• req.period.max = period->max;
• ret = xen_snd_front_stream_query_hw_param(&stream->evt_pair->req,

• 				  &req, &resp);
  

• if (ret < 0) {

• /* check if this is due to backend communication error */
  

• if (ret == -EIO || ret == -ETIMEDOUT)
  

• 	dev_err(dev, "Failed to query ALSA HW parameters\n");
  

• return ret;
  

• }
• /* refine HW parameters after the query */
• changed = 0;
• sndif_formats = to_alsa_formats_mask(resp.formats);
• snd_mask_none(&mask);
• mask.bits[0] = (u32)sndif_formats;
• mask.bits[1] = (u32)(sndif_formats >> 32);
• ret = snd_mask_refine(formats, &mask);
• if (ret < 0)

• return ret;
  

• changed |= ret;
• interval.openmin = 0;
• interval.openmax = 0;
• interval.integer = 1;
• interval.min = resp.rates.min;
• interval.max = resp.rates.max;
• ret = snd_interval_refine(rates, &interval);
• if (ret < 0)

• return ret;
  

• changed |= ret;
• interval.min = resp.channels.min;
• interval.max = resp.channels.max;
• ret = snd_interval_refine(channels, &interval);
• if (ret < 0)

• return ret;
  

• changed |= ret;
• interval.min = resp.buffer.min;
• interval.max = resp.buffer.max;
• ret = snd_interval_refine(buffer, &interval);
• if (ret < 0)

• return ret;
  

• changed |= ret;
• interval.min = resp.period.min;
• interval.max = resp.period.max;
• ret = snd_interval_refine(period, &interval);
• if (ret < 0)

• return ret;
  

• changed |= ret;
• return changed;

+}

+static int alsa_open(struct snd_pcm_substream *substream) +{

• struct pcm_instance_info *pcm_instance =

• 	snd_pcm_substream_chip(substream);
  

• struct pcm_stream_info *stream = stream_get(substream);
• struct snd_pcm_runtime *runtime = substream->runtime;
• struct xen_snd_front_info *front_info =

• 	pcm_instance->card_info->front_info;
  

• struct device *dev = &front_info->xb_dev->dev;
• unsigned long flags;
• int ret;
• /*

• * return our HW properties: override defaults with those configured
  

• * via XenStore
  

• */
  

• runtime->hw = stream->pcm_hw;
• runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP |

• 	      SNDRV_PCM_INFO_MMAP_VALID |
  

• 	      SNDRV_PCM_INFO_DOUBLE |
  

• 	      SNDRV_PCM_INFO_BATCH |
  

• 	      SNDRV_PCM_INFO_NONINTERLEAVED |
  

• 	      SNDRV_PCM_INFO_RESUME |
  

• 	      SNDRV_PCM_INFO_PAUSE);
  

• runtime->hw.info |= SNDRV_PCM_INFO_INTERLEAVED;
• spin_lock_irqsave(&front_info->io_lock, flags);
• stream->evt_pair = &front_info->evt_pairs[stream->index];
• stream->front_info = front_info;
• xen_snd_front_evtchnl_pair_set_connected(stream->evt_pair, true);
• stream->evt_pair->evt.u.evt.substream = substream;
• stream_clear(stream);
• spin_unlock_irqrestore(&front_info->io_lock, flags);
• ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,

• 		  alsa_hw_rule, stream,
  

• 		  SNDRV_PCM_HW_PARAM_FORMAT, -1);
  

• if (ret) {

• dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_FORMAT\n");
  

• return ret;
  

• }
• ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,

• 		  alsa_hw_rule, stream,
  

• 		  SNDRV_PCM_HW_PARAM_RATE, -1);
  

• if (ret) {

• dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_RATE\n");
  

• return ret;
  

• }
• ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,

• 		  alsa_hw_rule, stream,
  

• 		  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
  

• if (ret) {

• dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_CHANNELS\n");
  

• return ret;
  

• }
• ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,

• 		  alsa_hw_rule, stream,
  

• 		  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
  

• if (ret) {

• dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_PERIOD_SIZE\n");
  

• return ret;
  

• }
• ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE,

• 		  alsa_hw_rule, stream,
  

• 		  SNDRV_PCM_HW_PARAM_BUFFER_SIZE, -1);
  

• if (ret) {

• dev_err(dev, "Failed to add HW rule for SNDRV_PCM_HW_PARAM_BUFFER_SIZE\n");
  

• return ret;
  

• }
• return 0;

+}

+static int alsa_close(struct snd_pcm_substream *substream) +{

• struct pcm_stream_info *stream = stream_get(substream);
• unsigned long flags;
• spin_lock_irqsave(&stream->front_info->io_lock, flags);
• xen_snd_front_evtchnl_pair_set_connected(stream->evt_pair, false);
• spin_unlock_irqrestore(&stream->front_info->io_lock, flags);
• return 0;

+}

+static int alsa_hw_params(struct snd_pcm_substream *substream,

• 	  struct snd_pcm_hw_params *params)
  

+{

• struct pcm_stream_info *stream = stream_get(substream);
• int ret;
• /*

• * this callback may be called multiple times,
  

• * so free the previously allocated shared buffer if any
  

• */
  

• stream_free(stream);
• ret = xen_snd_front_shbuf_alloc(stream->front_info->xb_dev,

• 			&stream->sh_buf,
  

• 			params_buffer_bytes(params));
  

• if (ret < 0) {

• stream_free(stream);
  

• dev_err(&stream->front_info->xb_dev->dev,
  

• 	"Failed to allocate buffers for stream with index %d\n",
  

• 	stream->index);
  

• return ret;
  

• }
• return 0;

+}

+static int alsa_hw_free(struct snd_pcm_substream *substream) +{

• struct pcm_stream_info *stream = stream_get(substream);
• int ret;
• ret = xen_snd_front_stream_close(&stream->evt_pair->req);
• stream_free(stream);
• return ret;

+}

+static int alsa_prepare(struct snd_pcm_substream *substream) +{

• struct pcm_stream_info *stream = stream_get(substream);
• if (!stream->is_open) {

• struct snd_pcm_runtime *runtime = substream->runtime;
  

• u8 sndif_format;
  

• int ret;
  

• sndif_format = to_sndif_format(runtime->format);
  

• if (sndif_format < 0) {
  

• 	dev_err(&stream->front_info->xb_dev->dev,
  

• 		"Unsupported sample format: %d\n",
  

• 		runtime->format);
  

• 	return sndif_format;
  

• }
  

• ret = xen_snd_front_stream_prepare(&stream->evt_pair->req,
  

• 				   &stream->sh_buf,
  

• 				   sndif_format,
  

• 				   runtime->channels,
  

• 				   runtime->rate,
  

• 				   snd_pcm_lib_buffer_bytes(substream),
  

• 				   snd_pcm_lib_period_bytes(substream));
  

• if (ret < 0)
  

• 	return ret;
  

• stream->is_open = true;
  

• }
• return 0;

+}

+static int alsa_trigger(struct snd_pcm_substream *substream, int cmd) +{

• struct pcm_stream_info *stream = stream_get(substream);
• int type;
• switch (cmd) {
• case SNDRV_PCM_TRIGGER_START:

• type = XENSND_OP_TRIGGER_START;
  

• break;
  

• case SNDRV_PCM_TRIGGER_RESUME:

• type = XENSND_OP_TRIGGER_RESUME;
  

• break;
  

• case SNDRV_PCM_TRIGGER_STOP:

• type = XENSND_OP_TRIGGER_STOP;
  

• break;
  

• case SNDRV_PCM_TRIGGER_SUSPEND:

• type = XENSND_OP_TRIGGER_PAUSE;
  

• break;
  

• default:

• return -EINVAL;
  

• }
• return xen_snd_front_stream_trigger(&stream->evt_pair->req, type);

+}

+void xen_snd_front_alsa_handle_cur_pos(struct xen_snd_front_evtchnl *evtchnl,

• 		       u64 pos_bytes)
  

+{

• struct snd_pcm_substream *substream = evtchnl->u.evt.substream;
• struct pcm_stream_info *stream = stream_get(substream);
• snd_pcm_uframes_t delta, new_hw_ptr, cur_frame;
• cur_frame = bytes_to_frames(substream->runtime, pos_bytes);
• delta = cur_frame - stream->be_cur_frame;
• stream->be_cur_frame = cur_frame;
• new_hw_ptr = (snd_pcm_uframes_t)atomic_read(&stream->hw_ptr);
• new_hw_ptr = (new_hw_ptr + delta) % substream->runtime->buffer_size;
• atomic_set(&stream->hw_ptr, (int)new_hw_ptr);
• stream->out_frames += delta;
• if (stream->out_frames > substream->runtime->period_size) {

• stream->out_frames %= substream->runtime->period_size;
  

• snd_pcm_period_elapsed(substream);
  

• }

+}

+static snd_pcm_uframes_t alsa_pointer(struct snd_pcm_substream *substream) +{

• struct pcm_stream_info *stream = stream_get(substream);
• return (snd_pcm_uframes_t)atomic_read(&stream->hw_ptr);

+}

+static int alsa_pb_copy_user(struct snd_pcm_substream *substream,

• 	     int channel, unsigned long pos, void __user *src,
  

• 	     unsigned long count)
  

+{

• struct pcm_stream_info *stream = stream_get(substream);
• if (unlikely(pos + count > stream->sh_buf.buffer_sz))

• return -EINVAL;
  

• if (copy_from_user(stream->sh_buf.buffer + pos, src, count))

• return -EFAULT;
  

• return xen_snd_front_stream_write(&stream->evt_pair->req, pos, count);

+}

+static int alsa_pb_copy_kernel(struct snd_pcm_substream *substream,

• 	       int channel, unsigned long pos, void *src,
  

• 	       unsigned long count)
  

+{

• struct pcm_stream_info *stream = stream_get(substream);
• if (unlikely(pos + count > stream->sh_buf.buffer_sz))

• return -EINVAL;
  

• memcpy(stream->sh_buf.buffer + pos, src, count);
• return xen_snd_front_stream_write(&stream->evt_pair->req, pos, count);

+}

+static int alsa_cap_copy_user(struct snd_pcm_substream *substream,

• 	      int channel, unsigned long pos, void __user *dst,
  

• 	      unsigned long count)
  

+{

• struct pcm_stream_info *stream = stream_get(substream);
• int ret;
• if (unlikely(pos + count > stream->sh_buf.buffer_sz))

• return -EINVAL;
  

• ret = xen_snd_front_stream_read(&stream->evt_pair->req, pos, count);
• if (ret < 0)

• return ret;
  

• return copy_to_user(dst, stream->sh_buf.buffer + pos, count) ?

• -EFAULT : 0;
  

+}

+static int alsa_cap_copy_kernel(struct snd_pcm_substream *substream,

• 		int channel, unsigned long pos, void *dst,
  

• 		unsigned long count)
  

+{

• struct pcm_stream_info *stream = stream_get(substream);
• int ret;
• if (unlikely(pos + count > stream->sh_buf.buffer_sz))

• return -EINVAL;
  

• ret = xen_snd_front_stream_read(&stream->evt_pair->req, pos, count);
• if (ret < 0)

• return ret;
  

• memcpy(dst, stream->sh_buf.buffer + pos, count);
• return 0;

+}

+static int alsa_pb_fill_silence(struct snd_pcm_substream *substream,

• 		int channel, unsigned long pos,
  

• 		unsigned long count)
  

+{

• struct pcm_stream_info *stream = stream_get(substream);
• if (unlikely(pos + count > stream->sh_buf.buffer_sz))

• return -EINVAL;
  

• memset(stream->sh_buf.buffer + pos, 0, count);
• return xen_snd_front_stream_write(&stream->evt_pair->req, pos, count);

+}

+/*

• • FIXME: The mmaped data transfer is asynchronous and there is no
• • ack signal from user-space when it is done. This is the
• • reason it is not implemented in the PV driver as we do need
• • to know when the buffer can be transferred to the backend.
• */

+static struct snd_pcm_ops snd_drv_alsa_playback_ops = {

• .open = alsa_open,
• .close = alsa_close,
• .ioctl = snd_pcm_lib_ioctl,
• .hw_params = alsa_hw_params,
• .hw_free = alsa_hw_free,
• .prepare = alsa_prepare,
• .trigger = alsa_trigger,
• .pointer = alsa_pointer,
• .copy_user = alsa_pb_copy_user,
• .copy_kernel = alsa_pb_copy_kernel,
• .fill_silence = alsa_pb_fill_silence,

+};

+static struct snd_pcm_ops snd_drv_alsa_capture_ops = {

• .open = alsa_open,
• .close = alsa_close,
• .ioctl = snd_pcm_lib_ioctl,
• .hw_params = alsa_hw_params,
• .hw_free = alsa_hw_free,
• .prepare = alsa_prepare,
• .trigger = alsa_trigger,
• .pointer = alsa_pointer,
• .copy_user = alsa_cap_copy_user,
• .copy_kernel = alsa_cap_copy_kernel,

+};

+static int new_pcm_instance(struct card_info *card_info,

• 	    struct xen_front_cfg_pcm_instance *instance_cfg,
  

• 	    struct pcm_instance_info *pcm_instance_info)
  

+{

• struct snd_pcm *pcm;
• int ret, i;
• dev_dbg(&card_info->front_info->xb_dev->dev,

• "New PCM device \"%s\" with id %d playback %d capture %d",
  

• instance_cfg->name,
  

• instance_cfg->device_id,
  

• instance_cfg->num_streams_pb,
  

• instance_cfg->num_streams_cap);
  

• pcm_instance_info->card_info = card_info;
• pcm_instance_info->pcm_hw = instance_cfg->pcm_hw;
• if (instance_cfg->num_streams_pb) {

• pcm_instance_info->streams_pb =
  

• 		devm_kcalloc(&card_info->card->card_dev,
  

• 			     instance_cfg->num_streams_pb,
  

• 			     sizeof(struct pcm_stream_info),
  

• 			     GFP_KERNEL);
  

• if (!pcm_instance_info->streams_pb)
  

• 	return -ENOMEM;
  

• }
• if (instance_cfg->num_streams_cap) {

• pcm_instance_info->streams_cap =
  

• 		devm_kcalloc(&card_info->card->card_dev,
  

• 			     instance_cfg->num_streams_cap,
  

• 			     sizeof(struct pcm_stream_info),
  

• 			     GFP_KERNEL);
  

• if (!pcm_instance_info->streams_cap)
  

• 	return -ENOMEM;
  

• }
• pcm_instance_info->num_pcm_streams_pb =

• 	instance_cfg->num_streams_pb;
  

• pcm_instance_info->num_pcm_streams_cap =

• 	instance_cfg->num_streams_cap;
  

• for (i = 0; i < pcm_instance_info->num_pcm_streams_pb; i++) {

• pcm_instance_info->streams_pb[i].pcm_hw =
  

• 	instance_cfg->streams_pb[i].pcm_hw;
  

• pcm_instance_info->streams_pb[i].index =
  

• 	instance_cfg->streams_pb[i].index;
  

• }
• for (i = 0; i < pcm_instance_info->num_pcm_streams_cap; i++) {

• pcm_instance_info->streams_cap[i].pcm_hw =
  

• 	instance_cfg->streams_cap[i].pcm_hw;
  

• pcm_instance_info->streams_cap[i].index =
  

• 	instance_cfg->streams_cap[i].index;
  

• }
• ret = snd_pcm_new(card_info->card, instance_cfg->name,

• 	  instance_cfg->device_id,
  

• 	  instance_cfg->num_streams_pb,
  

• 	  instance_cfg->num_streams_cap,
  

• 	  &pcm);
  

• if (ret < 0)

• return ret;
  

• pcm->private_data = pcm_instance_info;
• pcm->info_flags = 0;
• /* we want to handle all PCM operations in non-atomic context */
• pcm->nonatomic = true;
• strncpy(pcm->name, "Virtual card PCM", sizeof(pcm->name));
• if (instance_cfg->num_streams_pb)

• snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
  

• 		&snd_drv_alsa_playback_ops);
  

• if (instance_cfg->num_streams_cap)

• snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE,
  

• 		&snd_drv_alsa_capture_ops);
  

• pcm_instance_info->pcm = pcm;
• return 0;

+}

+int xen_snd_front_alsa_init(struct xen_snd_front_info *front_info) +{

• struct device *dev = &front_info->xb_dev->dev;
• struct xen_front_cfg_card *cfg = &front_info->cfg;
• struct card_info *card_info;
• struct snd_card *card;
• int ret, i;
• dev_dbg(dev, "Creating virtual sound card\n");
• ret = snd_card_new(dev, 0, XENSND_DRIVER_NAME, THIS_MODULE,

• 	   sizeof(struct card_info), &card);
  

• if (ret < 0)

• return ret;
  

• card_info = card->private_data;
• card_info->front_info = front_info;
• front_info->card_info = card_info;
• card_info->card = card;
• card_info->pcm_instances =

• 	devm_kcalloc(dev, cfg->num_pcm_instances,
  

• 		     sizeof(struct pcm_instance_info),
  

• 		     GFP_KERNEL);
  

• if (!card_info->pcm_instances) {

• ret = -ENOMEM;
  

• goto fail;
  

• }
• card_info->num_pcm_instances = cfg->num_pcm_instances;
• card_info->pcm_hw = cfg->pcm_hw;
• for (i = 0; i < cfg->num_pcm_instances; i++) {

• ret = new_pcm_instance(card_info, &cfg->pcm_instances[i],
  

• 		       &card_info->pcm_instances[i]);
  

• if (ret < 0)
  

• 	goto fail;
  

• }
• strncpy(card->driver, XENSND_DRIVER_NAME, sizeof(card->driver));
• strncpy(card->shortname, cfg->name_short, sizeof(card->shortname));
• strncpy(card->longname, cfg->name_long, sizeof(card->longname));
• ret = snd_card_register(card);
• if (ret < 0)

• goto fail;
  

• return 0;

+fail:

• snd_card_free(card);
• return ret;

+}

+void xen_snd_front_alsa_fini(struct xen_snd_front_info *front_info) +{

• struct card_info *card_info;
• struct snd_card *card;
• card_info = front_info->card_info;
• if (!card_info)

• return;
  

• card = card_info->card;
• if (!card)

• return;
  

• dev_dbg(&front_info->xb_dev->dev, "Removing virtual sound card %d\n",

• card->number);
  

• snd_card_free(card);
• /* card_info will be freed when destroying front_info->xb_dev->dev */
• card_info->card = NULL;

+} diff --git a/sound/xen/xen_snd_front_alsa.h b/sound/xen/xen_snd_front_alsa.h new file mode 100644 index 000000000000..18abd9eec967 --- /dev/null +++ b/sound/xen/xen_snd_front_alsa.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 OR MIT */

+/*

• • Xen para-virtual sound device
• • Copyright (C) 2016-2018 EPAM Systems Inc.
• • Author: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
• */

+#ifndef __XEN_SND_FRONT_ALSA_H +#define __XEN_SND_FRONT_ALSA_H

+struct xen_snd_front_info;

+int xen_snd_front_alsa_init(struct xen_snd_front_info *front_info);

+void xen_snd_front_alsa_fini(struct xen_snd_front_info *front_info);

+void xen_snd_front_alsa_handle_cur_pos(struct xen_snd_front_evtchnl *evtchnl,

• 		       u64 pos_bytes);
  

+#endif /* __XEN_SND_FRONT_ALSA_H */ diff --git a/sound/xen/xen_snd_front_evtchnl.c b/sound/xen/xen_snd_front_evtchnl.c index 9ece39f938f8..470196518716 100644 --- a/sound/xen/xen_snd_front_evtchnl.c +++ b/sound/xen/xen_snd_front_evtchnl.c @@ -14,6 +14,7 @@ #include <xen/xenbus.h>

#include "xen_snd_front.h" +#include "xen_snd_front_alsa.h" #include "xen_snd_front_cfg.h" #include "xen_snd_front_evtchnl.h"

@@ -111,7 +112,10 @@ static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id)

switch (event->type) {
case XENSND_EVT_CUR_POS:

• 	/* do nothing at the moment */
  

• 	spin_unlock_irqrestore(&front_info->io_lock, flags);
  

• 	xen_snd_front_alsa_handle_cur_pos(channel,
  

• 					  event->op.cur_pos.position);
  

• 	spin_lock_irqsave(&front_info->io_lock, flags);
  

Is this correct? Why can you free the lock here without doing any harm? What is the lock protecting? I'd like to see at least some comments explaining why the lock is needed and why it can be dropped here.

Juergen