[PATCH v8 4/5] drm/client: Hack: Add bootsplash example

["Noralf Trønnes" <noralf@tronnes.org>]

An example to showcase the client API.

TODO:
- A bootsplash client needs a way to tell drm_fb_helper to stay away,
  otherwise it will chime in on setup and hotplug.
  Most DRM drivers register fbdev before calling drm_dev_register() (the
  generic emulation is an exception). This have to be reversed for
  bootsplash to fend off fbdev.
- Probably need some way to determine which is the primary display/device
  on multi DRM device systems.
- Maybe do handover from early/simple DRM driver

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
---
 drivers/gpu/drm/Kconfig          |   5 +
 drivers/gpu/drm/Makefile         |   1 +
 drivers/gpu/drm/drm_bootsplash.c | 358 +++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_client.c     |   7 +
 drivers/gpu/drm/drm_drv.c        |   4 +
 include/drm/drm_client.h         |   3 +
 6 files changed, 378 insertions(+)
 create mode 100644 drivers/gpu/drm/drm_bootsplash.c

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 6b34949416b1..d77a67cf3a89 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -66,6 +66,11 @@ config DRM_DEBUG_SELFTEST
 
 	  If in doubt, say "N".
 
+config DRM_CLIENT_BOOTSPLASH
+	bool "DRM Bootsplash"
+	help
+	  DRM Bootsplash
+
 config DRM_KMS_HELPER
 	tristate
 	depends on DRM
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index d36feb4a6233..86a2ceb95838 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -31,6 +31,7 @@ drm-$(CONFIG_OF) += drm_of.o
 drm-$(CONFIG_AGP) += drm_agpsupport.o
 drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
 drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
+drm-$(CONFIG_DRM_CLIENT_BOOTSPLASH) += drm_bootsplash.o
 
 drm_vram_helper-y := drm_gem_vram_helper.o \
 		     drm_vram_helper_common.o \
diff --git a/drivers/gpu/drm/drm_bootsplash.c b/drivers/gpu/drm/drm_bootsplash.c
new file mode 100644
index 000000000000..f58ee19e268f
--- /dev/null
+++ b/drivers/gpu/drm/drm_bootsplash.c
@@ -0,0 +1,358 @@
+/* DRM internal client example */
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/keyboard.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include <drm/drm_client.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_print.h>
+
+// drm_lastclose()
+#include "drm_internal.h"
+
+static bool drm_bootsplash_enabled = true;
+module_param_named(bootsplash_enabled, drm_bootsplash_enabled, bool, 0600);
+MODULE_PARM_DESC(bootsplash_enabled, "Enable bootsplash client [default=true]");
+
+struct drm_bootsplash {
+	struct drm_client_dev client;
+	struct mutex lock;
+	struct work_struct worker;
+	struct drm_client_buffer *buffers[2];
+	bool started;
+	bool stop;
+};
+
+static bool drm_bootsplash_key_pressed;
+
+static int drm_bootsplash_keyboard_notifier_call(struct notifier_block *blk,
+						 unsigned long code, void *_param)
+{
+	/* Any key is good */
+	drm_bootsplash_key_pressed = true;
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block drm_bootsplash_keyboard_notifier_block = {
+	.notifier_call = drm_bootsplash_keyboard_notifier_call,
+};
+
+static void drm_bootsplash_buffer_delete(struct drm_bootsplash *splash)
+{
+	unsigned int i;
+
+	for (i = 0; i < 2; i++) {
+		if (!IS_ERR_OR_NULL(splash->buffers[i]))
+			drm_client_framebuffer_delete(splash->buffers[i]);
+		splash->buffers[i] = NULL;
+	}
+}
+
+static int drm_bootsplash_buffer_create(struct drm_bootsplash *splash, u32 width, u32 height)
+{
+	unsigned int i;
+
+	for (i = 0; i < 2; i++) {
+		splash->buffers[i] = drm_client_framebuffer_create(&splash->client, width, height, DRM_FORMAT_XRGB8888);
+		if (IS_ERR(splash->buffers[i])) {
+			drm_bootsplash_buffer_delete(splash);
+			return PTR_ERR(splash->buffers[i]);
+		}
+	}
+
+	return 0;
+}
+
+static int drm_bootsplash_display_probe(struct drm_bootsplash *splash)
+{
+	struct drm_client_dev *client = &splash->client;
+	unsigned int width = 0, height = 0;
+	unsigned int num_non_tiled = 0, i;
+	unsigned int modeset_mask = 0;
+	struct drm_mode_set *modeset;
+	bool tiled = false;
+	int ret;
+
+	ret = drm_client_modeset_probe(client, 0, 0);
+	if (ret)
+		return ret;
+
+	mutex_lock(&client->modeset_mutex);
+
+	drm_client_for_each_modeset(modeset, client) {
+		if (!modeset->mode)
+			continue;
+
+		if (modeset->connectors[0]->has_tile)
+			tiled = true;
+		else
+			num_non_tiled++;
+	}
+
+	if (!tiled && !num_non_tiled) {
+		drm_bootsplash_buffer_delete(splash);
+		ret = -ENOENT;
+		goto out;
+	}
+
+	/* Assume only one tiled monitor is possible */
+	if (tiled) {
+		int hdisplay = 0, vdisplay = 0;
+
+		i = 0;
+		drm_client_for_each_modeset(modeset, client) {
+			i++;
+			if (!modeset->connectors[0]->has_tile)
+				continue;
+
+			if (!modeset->y)
+				hdisplay += modeset->mode->hdisplay;
+			if (!modeset->x)
+				vdisplay += modeset->mode->vdisplay;
+			modeset_mask |= BIT(i - 1);
+		}
+
+		width = hdisplay;
+		height = vdisplay;
+
+		goto trim;
+	}
+
+	/* The rest have one display (maybe cloned) per modeset, pick the largest */
+	i = 0;
+	drm_client_for_each_modeset(modeset, client) {
+		i++;
+		if (!modeset->mode || modeset->connectors[0]->has_tile)
+			continue;
+
+		if (modeset->mode->hdisplay * modeset->mode->vdisplay > width * height) {
+			width = modeset->mode->hdisplay;
+			height = modeset->mode->vdisplay;
+			modeset_mask = BIT(i - 1);
+		}
+	}
+
+trim:
+	/* Remove unused modesets (warning in __drm_atomic_helper_set_config()) */
+	i = 0;
+	drm_client_for_each_modeset(modeset, client) {
+		unsigned int j;
+
+		if (modeset_mask & BIT(i++))
+			continue;
+		drm_mode_destroy(client->dev, modeset->mode);
+		modeset->mode = NULL;
+
+		for (j = 0; j < modeset->num_connectors; j++) {
+			drm_connector_put(modeset->connectors[j]);
+			modeset->connectors[j] = NULL;
+		}
+		modeset->num_connectors = 0;
+	}
+
+	if (!splash->buffers[0] ||
+	    splash->buffers[0]->fb->width != width ||
+	    splash->buffers[0]->fb->height != height) {
+		drm_bootsplash_buffer_delete(splash);
+		ret = drm_bootsplash_buffer_create(splash, width, height);
+	}
+
+out:
+	mutex_unlock(&client->modeset_mutex);
+
+	return ret;
+}
+
+static int drm_bootsplash_display_commit_buffer(struct drm_bootsplash *splash, unsigned int num)
+{
+	struct drm_client_dev *client = &splash->client;
+	struct drm_mode_set *modeset;
+
+	mutex_lock(&client->modeset_mutex);
+	drm_client_for_each_modeset(modeset, client) {
+		if (modeset->mode)
+			modeset->fb = splash->buffers[num]->fb;
+	}
+	mutex_unlock(&client->modeset_mutex);
+
+	return drm_client_modeset_commit(client);
+}
+
+static u32 drm_bootsplash_color_table[3] = {
+	0x00ff0000, 0x0000ff00, 0x000000ff,
+};
+
+/* Draw a box with changing colors */
+static void drm_bootsplash_draw_box(struct drm_client_buffer *buffer, unsigned int sequence)
+{
+	unsigned int width = buffer->fb->width;
+	unsigned int height = buffer->fb->height;
+	unsigned int x, y;
+	u32 *pix;
+
+	pix = buffer->vaddr;
+	pix += ((height / 2) - 50) * width;
+	pix += (width / 2) - 50;
+
+	for (y = 0; y < 100; y++) {
+		for (x = 0; x < 100; x++)
+			*pix++ = drm_bootsplash_color_table[sequence];
+		pix += width - 100;
+	}
+}
+
+static int drm_bootsplash_draw(struct drm_bootsplash *splash, unsigned int sequence, unsigned int buffer_num)
+{
+	if (!splash->buffers[buffer_num])
+		return -ENOENT;
+
+	DRM_DEBUG_KMS("draw: buffer_num=%u, sequence=%u\n", buffer_num, sequence);
+
+	drm_bootsplash_draw_box(splash->buffers[buffer_num], sequence);
+
+	return drm_bootsplash_display_commit_buffer(splash, buffer_num);
+}
+
+static void drm_bootsplash_worker(struct work_struct *work)
+{
+	struct drm_bootsplash *splash = container_of(work, struct drm_bootsplash, worker);
+	struct drm_client_dev *client = &splash->client;
+	struct drm_device *dev = client->dev;
+	unsigned int buffer_num = 0, sequence = 0;
+	bool stop = false;
+	int ret = 0;
+
+	while (!drm_bootsplash_key_pressed) {
+		mutex_lock(&splash->lock);
+
+		stop = splash->stop;
+
+		buffer_num = !buffer_num;
+
+		ret = drm_bootsplash_draw(splash, sequence, buffer_num);
+
+		mutex_unlock(&splash->lock);
+
+		if (stop || ret == -ENOENT || ret == -EBUSY)
+			break;
+
+		if (++sequence == 3)
+			sequence = 0;
+
+		msleep(500);
+	}
+
+	/* Restore fbdev (or other) on key press. */
+	/* TODO: Check if it's OK to call drm_lastclose here. */
+	if (drm_bootsplash_key_pressed && !splash->stop)
+		drm_lastclose(dev);
+
+	drm_bootsplash_buffer_delete(splash);
+
+	DRM_DEV_DEBUG_KMS(dev->dev, "Bootsplash has stopped (key=%u stop=%u, ret=%d).\n",
+			  drm_bootsplash_key_pressed, splash->stop, ret);
+}
+
+static int drm_bootsplash_client_hotplug(struct drm_client_dev *client)
+{
+	struct drm_bootsplash *splash = container_of(client, struct drm_bootsplash, client);
+	int ret = 0;
+
+	if (drm_bootsplash_key_pressed)
+		return 0;
+
+	mutex_lock(&splash->lock);
+
+	if (splash->stop)
+		goto out_unlock;
+
+	ret = drm_bootsplash_display_probe(splash);
+	if (ret < 0) {
+		if (splash->started && ret == -ENOENT)
+			splash->stop = true;
+		goto out_unlock;
+	}
+
+	/*
+	 * TODO: Deal with rotated panels, might have to sw rotate
+	if (drm_client_panel_rotation(...))
+	 */
+
+	if (!splash->started) {
+		splash->started = true;
+		schedule_work(&splash->worker);
+	}
+
+out_unlock:
+	mutex_unlock(&splash->lock);
+
+	return ret;
+}
+
+static void drm_bootsplash_client_unregister(struct drm_client_dev *client)
+{
+	struct drm_bootsplash *splash = container_of(client, struct drm_bootsplash, client);
+
+	DRM_DEBUG_KMS("%s: IN\n", __func__);
+
+	mutex_lock(&splash->lock);
+	splash->stop = true;
+	mutex_unlock(&splash->lock);
+
+	flush_work(&splash->worker);
+
+	drm_client_release(client);
+	kfree(splash);
+
+	unregister_keyboard_notifier(&drm_bootsplash_keyboard_notifier_block);
+
+	DRM_DEBUG_KMS("%s: OUT\n", __func__);
+}
+
+static const struct drm_client_funcs drm_bootsplash_client_funcs = {
+	.owner		= THIS_MODULE,
+	.unregister	= drm_bootsplash_client_unregister,
+	.hotplug	= drm_bootsplash_client_hotplug,
+};
+
+void drm_bootsplash_client_register(struct drm_device *dev)
+{
+	struct drm_bootsplash *splash;
+	int ret;
+
+	if (!drm_bootsplash_enabled)
+		return;
+
+	splash = kzalloc(sizeof(*splash), GFP_KERNEL);
+	if (!splash)
+		return;
+
+	ret = drm_client_init(dev, &splash->client, "bootsplash", &drm_bootsplash_client_funcs);
+	if (ret) {
+		DRM_DEV_ERROR(dev->dev, "Failed to create client, ret=%d\n", ret);
+		kfree(splash);
+		return;
+	}
+
+	/* For this simple example only allow the first */
+	drm_bootsplash_enabled = false;
+
+	mutex_init(&splash->lock);
+
+	INIT_WORK(&splash->worker, drm_bootsplash_worker);
+
+	register_keyboard_notifier(&drm_bootsplash_keyboard_notifier_block);
+
+	drm_bootsplash_client_hotplug(&splash->client);
+
+	drm_client_register(&splash->client);
+}
diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
index 410572f14257..2813b0cbdf39 100644
--- a/drivers/gpu/drm/drm_client.c
+++ b/drivers/gpu/drm/drm_client.c
@@ -161,6 +161,13 @@ void drm_client_release(struct drm_client_dev *client)
 }
 EXPORT_SYMBOL(drm_client_release);
 
+void drm_client_dev_register(struct drm_device *dev)
+{
+#if CONFIG_DRM_CLIENT_BOOTSPLASH
+	drm_bootsplash_client_register(dev);
+#endif
+}
+
 void drm_client_dev_unregister(struct drm_device *dev)
 {
 	struct drm_client_dev *client, *tmp;
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 95a55d98e152..754e34aed92e 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -1017,6 +1017,10 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
 out_unlock:
 	mutex_unlock(&drm_global_mutex);
+
+	if (!ret)
+		drm_client_dev_register(dev);
+
 	return ret;
 }
 EXPORT_SYMBOL(drm_dev_register);
diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
index f2d5ed745733..e9eb770093fb 100644
--- a/include/drm/drm_client.h
+++ b/include/drm/drm_client.h
@@ -107,6 +107,7 @@ int drm_client_init(struct drm_device *dev, struct drm_client_dev *client,
 void drm_client_release(struct drm_client_dev *client);
 void drm_client_register(struct drm_client_dev *client);
 
+void drm_client_dev_register(struct drm_device *dev);
 void drm_client_dev_unregister(struct drm_device *dev);
 void drm_client_dev_hotplug(struct drm_device *dev);
 void drm_client_dev_restore(struct drm_device *dev);
@@ -183,4 +184,6 @@ int drm_client_modeset_dpms(struct drm_client_dev *client, int mode);
 
 int drm_client_debugfs_init(struct drm_minor *minor);
 
+void drm_bootsplash_client_register(struct drm_device *dev);
+
 #endif
-- 
2.20.1

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