Merge branch 'topic/xen' into for-next

Merge Xen para-virtualized frontend driver from Oleksandr Andrushchenko.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

15 files changed, 2708 insertions, 1 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 92be777d060a..bd214e061359 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15494,6 +15494,13 @@ S:	Supported
 F:	arch/x86/xen/*swiotlb*
 F:	drivers/xen/*swiotlb*
 
+XEN SOUND FRONTEND DRIVER
+M:	Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
+L:	xen-devel@lists.xenproject.org (moderated for non-subscribers)
+L:	alsa-devel@alsa-project.org (moderated for non-subscribers)
+S:	Supported
+F:	sound/xen/*
+
 XFS FILESYSTEM
 M:	Darrick J. Wong <darrick.wong@oracle.com>
 M:	linux-xfs@vger.kernel.org
diff --git a/sound/Kconfig b/sound/Kconfig
index 6833db9002ec..1140e9988fc5 100644
--- a/sound/Kconfig
+++ b/sound/Kconfig
@@ -96,6 +96,8 @@ source "sound/x86/Kconfig"
 
 source "sound/synth/Kconfig"
 
+source "sound/xen/Kconfig"
+
 endif # SND
 
 endif # !UML
diff --git a/sound/Makefile b/sound/Makefile
index 99d8c31262c8..797ecdcd35e2 100644
--- a/sound/Makefile
+++ b/sound/Makefile
@@ -5,7 +5,7 @@
 obj-$(CONFIG_SOUND) += soundcore.o
 obj-$(CONFIG_DMASOUND) += oss/dmasound/
 obj-$(CONFIG_SND) += core/ i2c/ drivers/ isa/ pci/ ppc/ arm/ sh/ synth/ usb/ \
-	firewire/ sparc/ spi/ parisc/ pcmcia/ mips/ soc/ atmel/ hda/ x86/
+	firewire/ sparc/ spi/ parisc/ pcmcia/ mips/ soc/ atmel/ hda/ x86/ xen/
 obj-$(CONFIG_SND_AOA) += aoa/
 
 # This one must be compilable even if sound is configured out
diff --git a/sound/xen/Kconfig b/sound/xen/Kconfig
new file mode 100644
index 000000000000..4f1fceea82d2
--- /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
+	select SND_PCM
+	select XEN_XENBUS_FRONTEND
+	help
+	  Choose this option if you want to enable a para-virtualized
+	  frontend sound driver for Xen guest OSes.
diff --git a/sound/xen/Makefile b/sound/xen/Makefile
new file mode 100644
index 000000000000..1e6470ecc2f2
--- /dev/null
+++ b/sound/xen/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0 OR MIT
+
+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_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
new file mode 100644
index 000000000000..c18973a9bc9b
--- /dev/null
+++ b/sound/xen/xen_snd_front.c
@@ -0,0 +1,397 @@
+// 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/delay.h>
+#include <linux/module.h>
+
+#include <xen/page.h>
+#include <xen/platform_pci.h>
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+
+#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 xensnd_req *req;
+	int ret;
+
+	mutex_lock(&evtchnl->u.req.req_io_lock);
+
+	mutex_lock(&evtchnl->ring_io_lock);
+	req = be_stream_prepare_req(evtchnl, XENSND_OP_HW_PARAM_QUERY);
+	req->op.hw_param = *hw_param_req;
+	mutex_unlock(&evtchnl->ring_io_lock);
+
+	ret = be_stream_do_io(evtchnl);
+
+	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 xensnd_req *req;
+	int ret;
+
+	mutex_lock(&evtchnl->u.req.req_io_lock);
+
+	mutex_lock(&evtchnl->ring_io_lock);
+	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);
+	mutex_unlock(&evtchnl->ring_io_lock);
+
+	ret = be_stream_do_io(evtchnl);
+
+	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 xensnd_req *req;
+	int ret;
+
+	mutex_lock(&evtchnl->u.req.req_io_lock);
+
+	mutex_lock(&evtchnl->ring_io_lock);
+	req = be_stream_prepare_req(evtchnl, XENSND_OP_CLOSE);
+	mutex_unlock(&evtchnl->ring_io_lock);
+
+	ret = be_stream_do_io(evtchnl);
+
+	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 xensnd_req *req;
+	int ret;
+
+	mutex_lock(&evtchnl->u.req.req_io_lock);
+
+	mutex_lock(&evtchnl->ring_io_lock);
+	req = be_stream_prepare_req(evtchnl, XENSND_OP_WRITE);
+	req->op.rw.length = count;
+	req->op.rw.offset = pos;
+	mutex_unlock(&evtchnl->ring_io_lock);
+
+	ret = be_stream_do_io(evtchnl);
+
+	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 xensnd_req *req;
+	int ret;
+
+	mutex_lock(&evtchnl->u.req.req_io_lock);
+
+	mutex_lock(&evtchnl->ring_io_lock);
+	req = be_stream_prepare_req(evtchnl, XENSND_OP_READ);
+	req->op.rw.length = count;
+	req->op.rw.offset = pos;
+	mutex_unlock(&evtchnl->ring_io_lock);
+
+	ret = be_stream_do_io(evtchnl);
+
+	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 xensnd_req *req;
+	int ret;
+
+	mutex_lock(&evtchnl->u.req.req_io_lock);
+
+	mutex_lock(&evtchnl->ring_io_lock);
+	req = be_stream_prepare_req(evtchnl, XENSND_OP_TRIGGER);
+	req->op.trigger.type = type;
+	mutex_unlock(&evtchnl->ring_io_lock);
+
+	ret = be_stream_do_io(evtchnl);
+
+	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);
+}
+
+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;
+
+	/* 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)
+{
+	return xen_snd_front_alsa_init(front_info);
+}
+
+static void sndback_disconnect(struct xen_snd_front_info *front_info)
+{
+	xen_snd_drv_fini(front_info);
+	xenbus_switch_state(front_info->xb_dev, XenbusStateInitialising);
+}
+
+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.
+		 */
+		break;
+
+	case XenbusStateUnknown:
+		/* fall through */
+	case XenbusStateClosed:
+		if (xb_dev->state == XenbusStateClosed)
+			break;
+
+		sndback_disconnect(front_info);
+		break;
+	}
+}
+
+static int xen_drv_probe(struct xenbus_device *xb_dev,
+			 const struct xenbus_device_id *id)
+{
+	struct xen_snd_front_info *front_info;
+
+	front_info = devm_kzalloc(&xb_dev->dev,
+				  sizeof(*front_info), GFP_KERNEL);
+	if (!front_info)
+		return -ENOMEM;
+
+	front_info->xb_dev = xb_dev;
+	dev_set_drvdata(&xb_dev->dev, front_info);
+
+	return xenbus_switch_state(xb_dev, XenbusStateInitialising);
+}
+
+static int xen_drv_remove(struct xenbus_device *dev)
+{
+	struct xen_snd_front_info *front_info = dev_get_drvdata(&dev->dev);
+	int to = 100;
+
+	xenbus_switch_state(dev, XenbusStateClosing);
+
+	/*
+	 * On driver removal it is disconnected from XenBus,
+	 * so no backend state change events come via .otherend_changed
+	 * callback. This prevents us from exiting gracefully, e.g.
+	 * signaling the backend to free event channels, waiting for its
+	 * state to change to XenbusStateClosed and cleaning at our end.
+	 * Normally when front driver removed backend will finally go into
+	 * XenbusStateInitWait state.
+	 *
+	 * Workaround: read backend's state manually and wait with time-out.
+	 */
+	while ((xenbus_read_unsigned(front_info->xb_dev->otherend, "state",
+				     XenbusStateUnknown) != XenbusStateInitWait) &&
+				     to--)
+		msleep(10);
+
+	if (!to) {
+		unsigned int state;
+
+		state = xenbus_read_unsigned(front_info->xb_dev->otherend,
+					     "state", XenbusStateUnknown);
+		pr_err("Backend state is %s while removing driver\n",
+		       xenbus_strstate(state));
+	}
+
+	xen_snd_drv_fini(front_info);
+	xenbus_frontend_closed(dev);
+	return 0;
+}
+
+static const struct xenbus_device_id xen_drv_ids[] = {
+	{ XENSND_DRIVER_NAME },
+	{ "" }
+};
+
+static struct xenbus_driver xen_driver = {
+	.ids = xen_drv_ids,
+	.probe = xen_drv_probe,
+	.remove = xen_drv_remove,
+	.otherend_changed = sndback_changed,
+};
+
+static int __init xen_drv_init(void)
+{
+	if (!xen_domain())
+		return -ENODEV;
+
+	if (!xen_has_pv_devices())
+		return -ENODEV;
+
+	/* 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;
+	}
+
+	pr_info("Initialising Xen " XENSND_DRIVER_NAME " frontend driver\n");
+	return xenbus_register_frontend(&xen_driver);
+}
+
+static void __exit xen_drv_fini(void)
+{
+	pr_info("Unregistering Xen " XENSND_DRIVER_NAME " frontend driver\n");
+	xenbus_unregister_driver(&xen_driver);
+}
+
+module_init(xen_drv_init);
+module_exit(xen_drv_fini);
+
+MODULE_DESCRIPTION("Xen virtual sound device frontend");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("xen:" XENSND_DRIVER_NAME);
+MODULE_SUPPORTED_DEVICE("{{ALSA,Virtual soundcard}}");
diff --git a/sound/xen/xen_snd_front.h b/sound/xen/xen_snd_front.h
new file mode 100644
index 000000000000..a2ea2463bcc5
--- /dev/null
+++ b/sound/xen/xen_snd_front.h
@@ -0,0 +1,54 @@
+/* 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_H
+#define __XEN_SND_FRONT_H
+
+#include "xen_snd_front_cfg.h"
+
+struct xen_snd_front_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 xen_snd_front_card_info *card_info;
+
+	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..5041f83e98d2
--- /dev/null
+++ b/sound/xen/xen_snd_front_alsa.c
@@ -0,0 +1,821 @@
+// 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 xen_snd_front_pcm_stream_info {
+	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 xen_snd_front_pcm_instance_info {
+	struct xen_snd_front_card_info *card_info;
+	struct snd_pcm *pcm;
+	struct snd_pcm_hardware pcm_hw;
+	int num_pcm_streams_pb;
+	struct xen_snd_front_pcm_stream_info *streams_pb;
+	int num_pcm_streams_cap;
+	struct xen_snd_front_pcm_stream_info *streams_cap;
+};
+
+struct xen_snd_front_card_info {
+	struct xen_snd_front_info *front_info;
+	struct snd_card *card;
+	struct snd_pcm_hardware pcm_hw;
+	int num_pcm_instances;
+	struct xen_snd_front_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 xen_snd_front_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 xen_snd_front_pcm_stream_info *stream)
+{
+	xen_snd_front_shbuf_free(&stream->sh_buf);
+	stream_clear(stream);
+}
+
+static struct xen_snd_front_pcm_stream_info *
+stream_get(struct snd_pcm_substream *substream)
+{
+	struct xen_snd_front_pcm_instance_info *pcm_instance =
+			snd_pcm_substream_chip(substream);
+	struct xen_snd_front_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 xen_snd_front_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 xen_snd_front_pcm_instance_info *pcm_instance =
+			snd_pcm_substream_chip(substream);
+	struct xen_snd_front_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;
+	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;
+
+	stream->evt_pair = &front_info->evt_pairs[stream->index];
+
+	stream->front_info = front_info;
+
+	stream->evt_pair->evt.u.evt.substream = substream;
+
+	stream_clear(stream);
+
+	xen_snd_front_evtchnl_pair_set_connected(stream->evt_pair, true);
+
+	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 xen_snd_front_pcm_stream_info *stream = stream_get(substream);
+
+	xen_snd_front_evtchnl_pair_set_connected(stream->evt_pair, false);
+	return 0;
+}
+
+static int alsa_hw_params(struct snd_pcm_substream *substream,
+			  struct snd_pcm_hw_params *params)
+{
+	struct xen_snd_front_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 xen_snd_front_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 xen_snd_front_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 xen_snd_front_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 xen_snd_front_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) {