[PATCH v2 1/8] drm/xen-front: Introduce Xen para-virtualized frontend driver

Oleksandr Andrushchenko
2018-03-13T13:33:43Z

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

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
---
drivers/gpu/drm/Kconfig | 2 ++
drivers/gpu/drm/Makefile | 1 +
drivers/gpu/drm/xen/Kconfig | 17 +++++++++
drivers/gpu/drm/xen/Makefile | 5 +++
drivers/gpu/drm/xen/xen_drm_front.c | 70 +++++++++++++++++++++++++++++++++++++
5 files changed, 95 insertions(+)
create mode 100644 drivers/gpu/drm/xen/Kconfig
create mode 100644 drivers/gpu/drm/xen/Makefile
create mode 100644 drivers/gpu/drm/xen/xen_drm_front.c

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index deeefa7a1773..757825ac60df 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -289,6 +289,8 @@ source "drivers/gpu/drm/pl111/Kconfig"

source "drivers/gpu/drm/tve200/Kconfig"

+source "drivers/gpu/drm/xen/Kconfig"
+
# Keep legacy drivers last

menuconfig DRM_LEGACY
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 50093ff4479b..9d66657ea117 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -103,3 +103,4 @@ obj-$(CONFIG_DRM_MXSFB) += mxsfb/
obj-$(CONFIG_DRM_TINYDRM) += tinydrm/
obj-$(CONFIG_DRM_PL111) += pl111/
obj-$(CONFIG_DRM_TVE200) += tve200/
+obj-$(CONFIG_DRM_XEN) += xen/
diff --git a/drivers/gpu/drm/xen/Kconfig b/drivers/gpu/drm/xen/Kconfig
new file mode 100644
index 000000000000..4cca160782ab
--- /dev/null
+++ b/drivers/gpu/drm/xen/Kconfig
@@ -0,0 +1,17 @@
+config DRM_XEN
+ bool "DRM Support for Xen guest OS"
+ depends on XEN
+ help
+ Choose this option if you want to enable DRM support
+ for Xen.
+
+config DRM_XEN_FRONTEND
+ tristate "Para-virtualized frontend driver for Xen guest OS"
+ depends on DRM_XEN
+ depends on DRM
+ select DRM_KMS_HELPER
+ select VIDEOMODE_HELPERS
+ select XEN_XENBUS_FRONTEND
+ help
+ Choose this option if you want to enable a para-virtualized
+ frontend DRM/KMS driver for Xen guest OSes.
diff --git a/drivers/gpu/drm/xen/Makefile b/drivers/gpu/drm/xen/Makefile
new file mode 100644
index 000000000000..3283e104c7bb
--- /dev/null
+++ b/drivers/gpu/drm/xen/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0 OR MIT
+
+drm_xen_front-objs := xen_drm_front.o
+
+obj-$(CONFIG_DRM_XEN_FRONTEND) += drm_xen_front.o
diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c
new file mode 100644
index 000000000000..03bc50b128fd
--- /dev/null
+++ b/drivers/gpu/drm/xen/xen_drm_front.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+/*
+ * Xen para-virtual DRM device
+ *
+ * Copyright (C) 2016-2018 EPAM Systems Inc.
+ *
+ * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
+ */
+
+#include <drm/drmP.h>
+
+#include <xen/platform_pci.h>
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+
+#include <xen/interface/io/displif.h>
+
+static void displback_changed(struct xenbus_device *xb_dev,
+ enum xenbus_state backend_state)
+{
+}
+
+static int xen_drv_probe(struct xenbus_device *xb_dev,
+ const struct xenbus_device_id *id)
+{
+ return 0;
+}
+
+static int xen_drv_remove(struct xenbus_device *dev)
+{
+ return 0;
+}
+
+static const struct xenbus_device_id xen_drv_ids[] = {
+ { XENDISPL_DRIVER_NAME },
+ { "" }
+};
+
+static struct xenbus_driver xen_driver = {
+ .ids = xen_drv_ids,
+ .probe = xen_drv_probe,
+ .remove = xen_drv_remove,
+ .otherend_changed = displback_changed,
+};
+
+static int __init xen_drv_init(void)
+{
+ if (!xen_domain())
+ return -ENODEV;
+
+ if (!xen_has_pv_devices())
+ return -ENODEV;
+
+ DRM_INFO("Registering XEN PV " XENDISPL_DRIVER_NAME "\n");
+ return xenbus_register_frontend(&xen_driver);
+}
+
+static void __exit xen_drv_cleanup(void)
+{
+ DRM_INFO("Unregistering XEN PV " XENDISPL_DRIVER_NAME "\n");
+ xenbus_unregister_driver(&xen_driver);
+}
+
+module_init(xen_drv_init);
+module_exit(xen_drv_cleanup);
+
+MODULE_DESCRIPTION("Xen para-virtualized display device frontend");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("xen:"XENDISPL_DRIVER_NAME);
--
2.7.4