[RESEND1,01/12] ALSA: vsnd: Introduce Xen para-virtualized sound frontend driver

Commit Message

Oleksandr Andrushchenko Aug. 7, 2017, 12:22 p.m. UTC

From: Oleksandr Andrushchenko <[e-mail]>

Introduce skeleton of the para-virtualized Xen sound
frontend driver. This patch only adds required
essential stubs.

Signed-off-by: Oleksandr Andrushchenko <[e-mail]>
---
 sound/drivers/xen-front.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 sound/drivers/xen-front.c

Patch

diff --git a/sound/drivers/xen-front.c b/sound/drivers/xen-front.c
new file mode 100644
index 000000000000..61779c36cae3
--- /dev/null
+++ b/sound/drivers/xen-front.c
@@ -0,0 +1,78 @@ 
+/*
+ * Xen para-virtual sound device
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ * Based on: sound/drivers/dummy.c
+ *
+ * Copyright (C) 2016-2017 EPAM Systems Inc.
+ *
+ * Author: Oleksandr Andrushchenko <[e-mail]>
+ */
+
+#include <linux/module.h>
+
+#include <xen/platform_pci.h>
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+
+#include <xen/interface/io/sndif.h>
+
+static void xdrv_be_on_changed(struct xenbus_device *xb_dev,
+	enum xenbus_state backend_state)
+{
+}
+
+static int xdrv_probe(struct xenbus_device *xb_dev,
+	const struct xenbus_device_id *id)
+{
+	return 0;
+}
+
+static int xdrv_remove(struct xenbus_device *dev)
+{
+	return 0;
+}
+
+static const struct xenbus_device_id xdrv_ids[] = {
+	{ XENSND_DRIVER_NAME },
+	{ "" }
+};
+
+static struct xenbus_driver xen_driver = {
+	.ids = xdrv_ids,
+	.probe = xdrv_probe,
+	.remove = xdrv_remove,
+	.otherend_changed = xdrv_be_on_changed,
+};
+
+static int __init xdrv_init(void)
+{
+	if (!xen_domain())
+		return -ENODEV;
+
+	pr_info("Initialising Xen " XENSND_DRIVER_NAME " frontend driver\n");
+	return xenbus_register_frontend(&xen_driver);
+}
+
+static void __exit xdrv_cleanup(void)
+{
+	pr_info("Unregistering Xen " XENSND_DRIVER_NAME " frontend driver\n");
+	xenbus_unregister_driver(&xen_driver);
+}
+
+module_init(xdrv_init);
+module_exit(xdrv_cleanup);
+
+MODULE_DESCRIPTION("Xen virtual sound device frontend");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("xen:"XENSND_DRIVER_NAME);
+MODULE_SUPPORTED_DEVICE("{{ALSA,Virtual soundcard}}");