[alsa-devel] [PATCH 06/11] ALSA: vsnd: Introduce ALSA virtual sound driver

[Oleksandr Andrushchenko]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko at 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

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko at epam.com>
---
 sound/drivers/xen-front.c | 161 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 159 insertions(+), 2 deletions(-)

diff --git a/sound/drivers/xen-front.c b/sound/drivers/xen-front.c
index 04ebc15757f4..f3e3f64f0aa6 100644
--- a/sound/drivers/xen-front.c
+++ b/sound/drivers/xen-front.c
@@ -19,13 +19,14 @@
  */
 
 #include <linux/module.h>
+#include <linux/platform_device.h>
 
 #include <sound/core.h>
 #include <sound/pcm.h>
 
-#include <xen/platform_pci.h>
 #include <xen/events.h>
 #include <xen/grant_table.h>
+#include <xen/platform_pci.h>
 #include <xen/xen.h>
 #include <xen/xenbus.h>
 
@@ -66,6 +67,33 @@ struct sh_buf_info {
 	size_t vbuffer_sz;
 };
 
+struct sdev_pcm_stream_info {
+	int unique_id;
+	struct snd_pcm_hardware pcm_hw;
+	struct xdrv_evtchnl_info *evt_chnl;
+	bool is_open;
+	uint8_t req_next_id;
+	struct sh_buf_info sh_buf;
+};
+
+struct sdev_pcm_instance_info {
+	struct sdev_card_info *card_info;
+	struct snd_pcm *pcm;
+	struct snd_pcm_hardware pcm_hw;
+	int num_pcm_streams_pb;
+	struct sdev_pcm_stream_info *streams_pb;
+	int num_pcm_streams_cap;
+	struct sdev_pcm_stream_info *streams_cap;
+};
+
+struct sdev_card_info {
+	struct xdrv_info *xdrv_info;
+	struct snd_card *card;
+	struct snd_pcm_hardware pcm_hw;
+	int num_pcm_instances;
+	struct sdev_pcm_instance_info *pcm_instances;
+};
+
 struct cfg_stream {
 	int unique_id;
 	char *xenstore_path;
@@ -99,6 +127,8 @@ struct xdrv_info {
 	struct xenbus_device *xb_dev;
 	spinlock_t io_lock;
 	struct mutex mutex;
+	bool sdrv_registered;
+	struct platform_device *sdrv_pdev;
 	int num_evt_channels;
 	struct xdrv_evtchnl_info *evt_chnls;
 	struct sdev_card_plat_data cfg_plat_data;
@@ -138,6 +168,132 @@ static struct snd_pcm_hardware sdrv_pcm_hw_default = {
 	.fifo_size = 0,
 };
 
+static int sdrv_new_pcm(struct sdev_card_info *card_info,
+	struct cfg_pcm_instance *instance_config,
+	struct sdev_pcm_instance_info *pcm_instance_info)
+{
+	return 0;
+}
+
+static int sdrv_probe(struct platform_device *pdev)
+{
+	struct sdev_card_info *card_info;
+	struct sdev_card_plat_data *platdata;
+	struct snd_card *card;
+	int ret, i;
+
+	platdata = dev_get_platdata(&pdev->dev);
+
+	dev_dbg(&pdev->dev, "Creating virtual sound card\n");
+
+	ret = snd_card_new(&pdev->dev, 0, XENSND_DRIVER_NAME, THIS_MODULE,
+		sizeof(struct sdev_card_info), &card);
+	if (ret < 0)
+		return ret;
+
+	card_info = card->private_data;
+	card_info->xdrv_info = platdata->xdrv_info;
+	card_info->card = card;
+	card_info->pcm_instances = devm_kcalloc(&pdev->dev,
+			platdata->cfg_card.num_pcm_instances,
+			sizeof(struct sdev_pcm_instance_info), GFP_KERNEL);
+	if (!card_info->pcm_instances) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	card_info->num_pcm_instances = platdata->cfg_card.num_pcm_instances;
+	card_info->pcm_hw = platdata->cfg_card.pcm_hw;
+
+	for (i = 0; i < platdata->cfg_card.num_pcm_instances; i++) {
+		ret = sdrv_new_pcm(card_info,
+			&platdata->cfg_card.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, platdata->cfg_card.name_short,
+		sizeof(card->shortname));
+	strncpy(card->longname, platdata->cfg_card.name_long,
+		sizeof(card->longname));
+
+	ret = snd_card_register(card);
+	if (ret < 0)
+		goto fail;
+
+	platform_set_drvdata(pdev, card);
+	return 0;
+
+fail:
+	snd_card_free(card);
+	return ret;
+}
+
+static int sdrv_remove(struct platform_device *pdev)
+{
+	struct sdev_card_info *info;
+	struct snd_card *card = platform_get_drvdata(pdev);
+
+	info = card->private_data;
+	dev_dbg(&pdev->dev, "Removing virtual sound card %d\n",
+		info->card->number);
+	snd_card_free(card);
+	return 0;
+}
+
+static struct platform_driver sdrv_info = {
+	.probe	= sdrv_probe,
+	.remove	= sdrv_remove,
+	.driver	= {
+		.name	= XENSND_DRIVER_NAME,
+	},
+};
+
+static void sdrv_cleanup(struct xdrv_info *drv_info)
+{
+	if (!drv_info->sdrv_registered)
+		return;
+
+	if (drv_info->sdrv_pdev) {
+		struct platform_device *sdrv_pdev;
+
+		sdrv_pdev = drv_info->sdrv_pdev;
+		if (sdrv_pdev)
+			platform_device_unregister(sdrv_pdev);
+	}
+	platform_driver_unregister(&sdrv_info);
+	drv_info->sdrv_registered = false;
+}
+
+static int sdrv_init(struct xdrv_info *drv_info)
+{
+	struct platform_device *sdrv_pdev;
+	int ret;
+
+	ret = platform_driver_register(&sdrv_info);
+	if (ret < 0)
+		return ret;
+
+	drv_info->sdrv_registered = true;
+	/* pass card configuration via platform data */
+	sdrv_pdev = platform_device_register_data(NULL,
+		XENSND_DRIVER_NAME, 0, &drv_info->cfg_plat_data,
+		sizeof(drv_info->cfg_plat_data));
+	if (IS_ERR(sdrv_pdev))
+		goto fail;
+
+	drv_info->sdrv_pdev = sdrv_pdev;
+	return 0;
+
+fail:
+	dev_err(&drv_info->xb_dev->dev,
+		"failed to register virtual sound driver\n");
+	sdrv_cleanup(drv_info);
+	return -ENODEV;
+}
+
 static irqreturn_t xdrv_evtchnl_interrupt(int irq, void *dev_id)
 {
 	struct xdrv_evtchnl_info *channel = dev_id;
@@ -830,6 +986,7 @@ static int cfg_card(struct xdrv_info *drv_info,
 
 static void xdrv_remove_internal(struct xdrv_info *drv_info)
 {
+	sdrv_cleanup(drv_info);
 	xdrv_evtchnl_free_all(drv_info);
 }
 
@@ -1018,7 +1175,7 @@ static int xdrv_be_on_initwait(struct xdrv_info *drv_info)
 
 static inline int xdrv_be_on_connected(struct xdrv_info *drv_info)
 {
-	return 0;
+	return sdrv_init(drv_info);
 }
 
 static inline void xdrv_be_on_disconnected(struct xdrv_info *drv_info)
-- 
2.7.4