video: mcde: Add tripple buffer support

This patch adds tripple buffer support to the mcde
driver. Useful for video mode devices (e.g. HDMI)
where a missed v-sync leads to half frame rate
(the client has to wait for the next v-sync).
Tripple buffering solves this problem since there
are two back buffers the client can use.

Tripple buffering for HDMI is activated in
menuconfig by enabling:
System Type -> Display selection -> Enable tripple
buffer for HDMI display

ST-Ericsson ID: 335004
ST-Ericsson Linux next: Not tested, ER 282779
ST-Ericsson FOSS-OUT ID: Trivial

Change-Id: Ice1f936a8a00e2fbc8fdf7e8c6621c539efe0ac4
Signed-off-by: Jimmy Rubin <jimmy.rubin@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/21839
Reviewed-by: QATOOLS
Reviewed-by: Per PERSSON <per.xb.persson@stericsson.com>
Reviewed-by: QATEST
Reviewed-by: Marcel TUNNISSEN <marcel.tuennissen@stericsson.com>

Conflicts:

	arch/arm/configs/u8500_defconfig
	drivers/misc/dispdev/dispdev.c

4 files changed, 29 insertions, 18 deletions

diff --git a/drivers/video/mcde/mcde_display.c b/drivers/video/mcde/mcde_display.c
index 521446dc26f..144a1a67d02 100644
--- a/drivers/video/mcde/mcde_display.c
+++ b/drivers/video/mcde/mcde_display.c
@@ -328,9 +328,10 @@ static int mcde_display_invalidate_area_default(
 	return 0;
 }
 
-static int mcde_display_update_default(struct mcde_display_device *ddev)
+static int mcde_display_update_default(struct mcde_display_device *ddev,
+							bool tripple_buffer)
 {
-	int ret;
+	int ret = 0;
 
 	/* TODO: Dirty */
 	if (ddev->prepare_for_update) {
@@ -344,7 +345,8 @@ static int mcde_display_update_default(struct mcde_display_device *ddev)
 		}
 	}
 	/* TODO: Calculate & set update rect */
-	ret = mcde_chnl_update(ddev->chnl_state, &ddev->update_area);
+	ret = mcde_chnl_update(ddev->chnl_state, &ddev->update_area,
+							tripple_buffer);
 	if (ret < 0) {
 		dev_warn(&ddev->dev, "%s:Failed to update channel\n", __func__);
 		return ret;
diff --git a/drivers/video/mcde/mcde_dss.c b/drivers/video/mcde/mcde_dss.c
index a53040f48e1..361510b46fc 100644
--- a/drivers/video/mcde/mcde_dss.c
+++ b/drivers/video/mcde/mcde_dss.c
@@ -242,10 +242,9 @@ void mcde_dss_disable_overlay(struct mcde_overlay *ovly)
 }
 EXPORT_SYMBOL(mcde_dss_disable_overlay);
 
-int mcde_dss_update_overlay(struct mcde_overlay *ovly)
+int mcde_dss_update_overlay(struct mcde_overlay *ovly, bool tripple_buffer)
 {
 	int ret;
-
 	dev_vdbg(&ovly->ddev->dev, "Overlay update, chnl=%d\n",
 							ovly->ddev->chnl_id);
 
@@ -256,7 +255,7 @@ int mcde_dss_update_overlay(struct mcde_overlay *ovly)
 	if (ovly->ddev->get_power_mode(ovly->ddev) == MCDE_DISPLAY_PM_OFF)
 		return 0;
 
-	ret = ovly->ddev->update(ovly->ddev);
+	ret = ovly->ddev->update(ovly->ddev, tripple_buffer);
 	if (ret)
 		return ret;
 
diff --git a/drivers/video/mcde/mcde_fb.c b/drivers/video/mcde/mcde_fb.c
index 039a60ad05c..dc0812761c7 100644
--- a/drivers/video/mcde/mcde_fb.c
+++ b/drivers/video/mcde/mcde_fb.c
@@ -507,10 +507,13 @@ static int apply_var(struct fb_info *fbi, struct mcde_display_device *ddev)
 	for (i = 0; i < mfb->num_ovlys; i++) {
 		struct mcde_overlay *ovly = mfb->ovlys[i];
 		struct mcde_overlay_info info;
+		int num_buffers;
 
 		get_ovly_info(fbi, ovly, &info);
 		(void) mcde_dss_apply_overlay(ovly, &info);
-		ret = mcde_dss_update_overlay(ovly);
+
+		num_buffers = var->yres_virtual / var->yres;
+		mcde_dss_update_overlay(ovly, num_buffers == 3);
 	}
 
 	return 0;
diff --git a/drivers/video/mcde/mcde_hw.c b/drivers/video/mcde/mcde_hw.c
index 7a0208df66e..9844dc1b2f7 100644
--- a/drivers/video/mcde/mcde_hw.c
+++ b/drivers/video/mcde/mcde_hw.c
@@ -964,18 +964,19 @@ static irqreturn_t mcde_irq_handler(int irq, void *dev)
 static void wait_for_channel(struct mcde_chnl_state *chnl)
 {
 	int ret;
+	u32 id = chnl->transactionid_regs;
 
-	if (chnl->transactionid_hw >= chnl->transactionid_regs)
+	if (chnl->transactionid_hw >= id)
 		return;
 
 	ret = wait_event_timeout(chnl->waitq_hw,
-		chnl->transactionid_hw == chnl->transactionid_regs,
+		chnl->transactionid_hw == id,
 		msecs_to_jiffies(CHNL_TIMEOUT));
 	if (!ret)
 		dev_warn(&mcde_dev->dev,
 			"Wait for channel timeout (chnl=%d,%d<%d)!\n",
 			chnl->id, chnl->transactionid_hw,
-			chnl->transactionid_regs);
+			id);
 }
 
 static int update_channel_static_registers(struct mcde_chnl_state *chnl)
@@ -2318,12 +2319,14 @@ static void chnl_update_registers(struct mcde_chnl_state *chnl)
 	chnl->transactionid_regs = chnl->transactionid;
 }
 
-static void chnl_update_continous(struct mcde_chnl_state *chnl)
+static void chnl_update_continous(struct mcde_chnl_state *chnl,
+						bool tripple_buffer)
 {
 
 	if (chnl->continous_running) {
 		chnl->transactionid_regs = chnl->transactionid;
-		wait_for_channel(chnl);
+		if (!tripple_buffer)
+			wait_for_channel(chnl);
 	}
 
 	if (!chnl->continous_running) {
@@ -2410,7 +2413,8 @@ static void chnl_update_overlay(struct mcde_chnl_state *chnl,
 }
 
 static int _mcde_chnl_update(struct mcde_chnl_state *chnl,
-					struct mcde_rectangle *update_area)
+					struct mcde_rectangle *update_area,
+					bool tripple_buffer)
 {
 	dev_vdbg(&mcde_dev->dev, "%s\n", __func__);
 
@@ -2420,6 +2424,9 @@ static int _mcde_chnl_update(struct mcde_chnl_state *chnl,
 		return -EINVAL;
 	}
 
+	if (chnl->port.update_auto_trig && tripple_buffer)
+		wait_for_channel(chnl);
+
 	chnl->regs.x   = update_area->x;
 	chnl->regs.y   = update_area->y;
 	/* TODO Crop against video_mode.xres and video_mode.yres */
@@ -2439,7 +2446,7 @@ static int _mcde_chnl_update(struct mcde_chnl_state *chnl,
 	chnl_update_overlay(chnl, chnl->ovly1);
 
 	if (chnl->port.update_auto_trig)
-		chnl_update_continous(chnl);
+		chnl_update_continous(chnl, tripple_buffer);
 	else
 		chnl_update_non_continous(chnl);
 
@@ -2608,10 +2615,10 @@ int mcde_chnl_apply(struct mcde_chnl_state *chnl)
 }
 
 int mcde_chnl_update(struct mcde_chnl_state *chnl,
-					struct mcde_rectangle *update_area)
+					struct mcde_rectangle *update_area,
+					bool tripple_buffer)
 {
 	int ret;
-
 	dev_vdbg(&mcde_dev->dev, "%s\n", __func__);
 
 	if (!chnl->reserved)
@@ -2623,7 +2630,6 @@ int mcde_chnl_update(struct mcde_chnl_state *chnl,
 		(void)update_channel_static_registers(chnl);
 
 	if (chnl->regs.roten && !chnl->esram_is_enabled) {
-		int ret;
 		ret = regulator_enable(chnl->port.reg_esram);
 		if (ret < 0) {
 			dev_warn(&mcde_dev->dev, "%s: disable failed\n",
@@ -2632,7 +2638,8 @@ int mcde_chnl_update(struct mcde_chnl_state *chnl,
 		chnl->esram_is_enabled = true;
 	}
 
-	ret = _mcde_chnl_update(chnl, update_area);
+	ret = _mcde_chnl_update(chnl, update_area, tripple_buffer);
+
 	mutex_unlock(&mcde_hw_lock);
 
 	dev_vdbg(&mcde_dev->dev, "%s exit with ret %d\n", __func__, ret);