[RFC 1/2] drm: Add SoC framework

Thierry Reding thierry.reding at avionic-design.de
Fri Jul 6 07:00:59 PDT 2012


This commit adds an initial framework that can be used to plug SoC
graphics devices into the DRM/KMS subsystem.

SoCs often don't have a dedicated device to which a DRM driver can bind,
but instead the graphics complex typically consists of several platform-
type devices that work together. The DRM SoC support code therefore adds
a dummy device that is associated with the DRM driver, which typically
provides some kind of API for other drivers to register with.

Signed-off-by: Thierry Reding <thierry.reding at avionic-design.de>
---
 drivers/gpu/drm/Kconfig   |   4 ++
 drivers/gpu/drm/Makefile  |   2 +
 drivers/gpu/drm/drm_soc.c | 151 ++++++++++++++++++++++++++++++++++++++++++++++
 include/drm/drmP.h        |   5 ++
 4 files changed, 162 insertions(+)
 create mode 100644 drivers/gpu/drm/drm_soc.c

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 23120c0..529dede 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -24,6 +24,10 @@ config DRM_USB
 	depends on DRM
 	select USB
 
+config DRM_SOC
+	tristate
+	depends on DRM
+
 config DRM_KMS_HELPER
 	tristate
 	depends on DRM
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index f65f65e..4731cbc 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -17,6 +17,7 @@ drm-y       :=	drm_auth.o drm_buffer.o drm_bufs.o drm_cache.o \
 drm-$(CONFIG_COMPAT) += drm_ioc32.o
 
 drm-usb-y   := drm_usb.o
+drm-soc-y   := drm_soc.o
 
 drm_kms_helper-y := drm_fb_helper.o drm_crtc_helper.o drm_dp_i2c_helper.o
 drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
@@ -27,6 +28,7 @@ CFLAGS_drm_trace_points.o := -I$(src)
 
 obj-$(CONFIG_DRM)	+= drm.o
 obj-$(CONFIG_DRM_USB)   += drm_usb.o
+obj-$(CONFIG_DRM_SOC)	+= drm-soc.o
 obj-$(CONFIG_DRM_TTM)	+= ttm/
 obj-$(CONFIG_DRM_TDFX)	+= tdfx/
 obj-$(CONFIG_DRM_R128)	+= r128/
diff --git a/drivers/gpu/drm/drm_soc.c b/drivers/gpu/drm/drm_soc.c
new file mode 100644
index 0000000..bc120ae
--- /dev/null
+++ b/drivers/gpu/drm/drm_soc.c
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2012 Avionic Design GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <drm/drmP.h>
+#include <drm/drm_sysfs.h>
+
+static const char *drm_soc_get_name(struct drm_device *dev)
+{
+	DRM_DEBUG("\n");
+	return dev_name(dev->dev);
+}
+
+static int drm_soc_set_busid(struct drm_device *dev, struct drm_master *master)
+{
+	DRM_DEBUG("\n");
+	return -ENOSYS;
+}
+
+static int drm_soc_set_unique(struct drm_device *dev, struct drm_master *master,
+			      struct drm_unique *unique)
+{
+	DRM_DEBUG("\n");
+	return -ENOSYS;
+}
+
+static struct drm_bus drm_soc_bus = {
+	.bus_type = DRIVER_BUS_SOC,
+	.get_name = drm_soc_get_name,
+	.set_busid = drm_soc_set_busid,
+	.set_unique = drm_soc_set_unique,
+};
+
+static struct device_type drm_soc_device_type = {
+	.name = "soc",
+};
+
+static void drm_soc_device_release(struct device *dev)
+{
+	kfree(dev);
+}
+
+static struct device *drm_create_soc_device(const char *name)
+{
+	struct device *dev;
+	int err;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return NULL;
+
+	dev->release = drm_soc_device_release;
+	dev->type = &drm_soc_device_type;
+	dev_set_name(dev, name);
+
+	err = drm_class_device_register(dev);
+	if (err < 0)
+		goto put;
+
+	return dev;
+
+put:
+	put_device(dev);
+	return NULL;
+}
+
+int drm_soc_init(struct drm_driver *driver, const char *name)
+{
+	struct drm_device *dev;
+	int ret;
+
+	INIT_LIST_HEAD(&driver->device_list);
+	driver->bus = &drm_soc_bus;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->dev = drm_create_soc_device(name);
+	if (!dev->dev) {
+		ret = -ENOMEM;
+		goto free;
+	}
+
+	ret = drm_fill_in_dev(dev, NULL, driver);
+	if (ret < 0)
+		goto unregister;
+
+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		ret = drm_get_minor(dev, &dev->control, DRM_MINOR_CONTROL);
+		if (ret < 0)
+			goto unregister;
+	}
+
+	ret = drm_get_minor(dev, &dev->primary, DRM_MINOR_LEGACY);
+	if (ret < 0)
+		goto put_control;
+
+	if (dev->driver->load) {
+		ret = dev->driver->load(dev, 0);
+		if (ret < 0)
+			goto put_legacy;
+	}
+
+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		ret = drm_mode_group_init_legacy_group(dev, &dev->primary->mode_group);
+		if (ret < 0)
+			goto put_legacy;
+	}
+
+	list_add_tail(&dev->driver_item, &driver->device_list);
+
+	DRM_INFO("Initialized %s %d.%d.%d %s on minor %d\n", driver->name,
+		 driver->major, driver->minor, driver->patchlevel,
+		 driver->date, dev->primary->index);
+
+	return 0;
+
+put_legacy:
+	drm_put_minor(&dev->primary);
+put_control:
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		drm_put_minor(&dev->control);
+unregister:
+	drm_class_device_unregister(dev->dev);
+free:
+	kfree(dev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(drm_soc_init);
+
+void drm_soc_exit(struct drm_driver *driver)
+{
+	struct drm_device *drm, *tmp;
+
+	list_for_each_entry_safe(drm, tmp, &driver->device_list, driver_item) {
+		struct device *dev = drm->dev;
+		drm_put_dev(drm);
+		drm_class_device_unregister(dev);
+	}
+}
+EXPORT_SYMBOL_GPL(drm_soc_exit);
+
+MODULE_AUTHOR("Thierry Reding <thierry.reding at avionic-design.de>");
+MODULE_DESCRIPTION("SoC DRM support");
+MODULE_LICENSE("GPL");
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 31ad880..bc1edd1 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -156,6 +156,7 @@ int drm_err(const char *func, const char *format, ...);
 #define DRIVER_BUS_PCI 0x1
 #define DRIVER_BUS_PLATFORM 0x2
 #define DRIVER_BUS_USB 0x3
+#define DRIVER_BUS_SOC 0x4
 
 /***********************************************************************/
 /** \name Begin the DRM... */
@@ -1769,6 +1770,10 @@ extern void drm_platform_exit(struct drm_driver *driver, struct platform_device
 extern int drm_get_platform_dev(struct platform_device *pdev,
 				struct drm_driver *driver);
 
+/* SoC section */
+extern int drm_soc_init(struct drm_driver *driver, const char *name);
+extern void drm_soc_exit(struct drm_driver *driver);
+
 /* returns true if currently okay to sleep */
 static __inline__ bool drm_can_sleep(void)
 {
-- 
1.7.11.1



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