s3cfb: asynchronous vsync notification

Change-Id: Id3642cd25475b3c872b1ae7d4b69d53f122dffa8

3 files changed, 63 insertions, 3 deletions

diff --git a/drivers/video/samsung/s3cfb.h b/drivers/video/samsung/s3cfb.h
index 6adb765..b278184 100644
--- a/drivers/video/samsung/s3cfb.h
+++ b/drivers/video/samsung/s3cfb.h
@@ -178,6 +178,10 @@ struct s3cfb_global {
 	unsigned int		wq_count;
 	struct fb_info		**fb;
 
+	ktime_t      vsync_timestamp;
+	int      vsync_state;
+	struct task_struct  *vsync_thread;
+
 	atomic_t		enabled_win;
 	enum s3cfb_output_t	output;
 	enum s3cfb_rgb_mode_t	rgb_mode;
diff --git a/drivers/video/samsung/s3cfb_main.c b/drivers/video/samsung/s3cfb_main.c
index a6e4564..2cb7c86 100644
--- a/drivers/video/samsung/s3cfb_main.c
+++ b/drivers/video/samsung/s3cfb_main.c
@@ -29,6 +29,7 @@
 #include <linux/memory.h>
 #include <linux/pm_runtime.h>
 #include <linux/delay.h>
+#include <linux/kthread.h>
 #include <plat/clock.h>
 #include <plat/media.h>
 #include <mach/media.h>
@@ -57,6 +58,8 @@
 #include <mach/regs-pmu.h>
 #include <plat/regs-fb-s5p.h>
 
+extern int s3cfb_vsync_timestamp_changed(struct s3cfb_global *fbdev, ktime_t prev_timestamp);
+
 struct s3cfb_fimd_desc		*fbfimd;
 
 inline struct s3cfb_global *get_fimd_global(int id)
@@ -91,7 +94,8 @@ static irqreturn_t s3cfb_irq_frame(int irq, void *dev_id)
 		s3cfb_clear_interrupt(fbdev[0]);
 
 	fbdev[0]->wq_count++;
-	wake_up(&fbdev[0]->wq);
+	fbdev[0]->vsync_timestamp = ktime_get();
+	wake_up_interruptible(&fbdev[0]->wq);
 
 	return IRQ_HANDLED;
 }
@@ -318,6 +322,32 @@ void s3cfb_trigger(void)
 EXPORT_SYMBOL(s3cfb_trigger);
 #endif
 
+static int s3cfb_wait_for_vsync_thread(void *data)
+{
+    struct s3cfb_global *fbdev = data;
+
+    while (!kthread_should_stop()) {
+        ktime_t prev_timestamp = fbdev->vsync_timestamp;
+
+        int ret = wait_event_interruptible_timeout(fbdev->wq,
+                        s3cfb_vsync_timestamp_changed(fbdev, prev_timestamp),
+                        msecs_to_jiffies(100));
+
+        if (ret > 0) {
+            char *envp[2];
+            char buf[64];
+
+            snprintf(buf, sizeof(buf), "VSYNC=%llu",
+            ktime_to_ns(fbdev->vsync_timestamp));
+            envp[0] = buf;
+            envp[1] = NULL;
+            kobject_uevent_env(&fbdev->dev->kobj, KOBJ_CHANGE, envp);
+        }
+    }
+
+    return 0;
+}
+
 static int s3cfb_probe(struct platform_device *pdev)
 {
 	struct s3c_platform_fb *pdata = NULL;
@@ -494,6 +524,12 @@ static int s3cfb_probe(struct platform_device *pdev)
 		pdata->lcd_on(pdev);
 #endif
 
+	fbdev[0]->vsync_thread = kthread_run(s3cfb_wait_for_vsync_thread, fbdev[0], "s3cfb-vsync");
+	if (fbdev[0]->vsync_thread == ERR_PTR(-ENOMEM)) {
+		dev_err(fbdev[0]->dev, "failed to run vsync thread\n");
+		fbdev[0]->vsync_thread = NULL;
+	}
+
 	ret = device_create_file(&(pdev->dev), &dev_attr_win_power);
 	if (ret < 0)
 		dev_err(fbdev[0]->dev, "failed to add sysfs entries\n");
@@ -565,6 +601,9 @@ static int s3cfb_remove(struct platform_device *pdev)
 			}
 		}
 
+		if (fbdev[i]->vsync_thread)
+			kthread_stop(fbdev[i]->vsync_thread);
+
 		kfree(fbdev[i]->fb);
 		kfree(fbdev[i]);
 	}
diff --git a/drivers/video/samsung/s3cfb_ops.c b/drivers/video/samsung/s3cfb_ops.c
index 3ff2f05..82ece16 100644
--- a/drivers/video/samsung/s3cfb_ops.c
+++ b/drivers/video/samsung/s3cfb_ops.c
@@ -1082,15 +1082,32 @@ int s3cfb_cursor(struct fb_info *fb, struct fb_cursor *cursor)
 	return 0;
 }
 
+int s3cfb_vsync_timestamp_changed(struct s3cfb_global *fbdev, ktime_t prev_timestamp)
+{
+	return !ktime_equal(prev_timestamp, fbdev->vsync_timestamp);
+}
+
 int s3cfb_wait_for_vsync(struct s3cfb_global *fbdev)
 {
+	ktime_t prev_timestamp;
+	int ret;
+
 	dev_dbg(fbdev->dev, "waiting for VSYNC interrupt\n");
 
-	sleep_on_timeout(&fbdev->wq, HZ / 10);
+	prev_timestamp = fbdev->vsync_timestamp;
+
+	ret = wait_event_interruptible_timeout(fbdev->wq, 
+				s3cfb_vsync_timestamp_changed(fbdev, prev_timestamp),
+				msecs_to_jiffies(100));
+
+	if (ret == 0)
+		return -ETIMEDOUT;
+	if (ret < 0)
+		return ret;
 
 	dev_dbg(fbdev->dev, "got a VSYNC interrupt\n");
 
-	return 0;
+	return ret;
 }
 
 int s3cfb_ioctl(struct fb_info *fb, unsigned int cmd, unsigned long arg)