ENGR00180348 EPDC: invalid data when width is 2048 or greater

This patch works around the 6DLS and 6SL chip errata:
ERR005313 EPDC: Incorrect data fetched when the buffer update width is
2048 pixels or greater

This patch breaks large updates into multiple updates, which works
around the problem on both 6DSL and 6SL. This patch does not use the
Group Update feature, which may improve things further on 6SL.

This patch does not include for support for any particular large panel.
It was tested on ED09705 (2400x1650). Support for ED09705 is
available in a separate patch.

Signed-off-by: Michael Minnick <michael.minnick@freescale.com>

1 files changed, 91 insertions, 10 deletions

diff --git a/drivers/video/mxc/mxc_epdc_fb.c b/drivers/video/mxc/mxc_epdc_fb.c
index 0405234608bb..b702788ae823 100644
--- a/drivers/video/mxc/mxc_epdc_fb.c
+++ b/drivers/video/mxc/mxc_epdc_fb.c
@@ -70,6 +70,10 @@
 #define INVALID_LUT		(-1)
 #define DRY_RUN_NO_LUT		100
 
+/* Maximum update buffer image width due to v2.0 and v2.1 errata ERR005313. */
+#define EPDC_V2_MAX_UPDATE_WIDTH	2047
+#define EPDC_V2_ROTATION_ALIGNMENT	8
+
 #define DEFAULT_TEMP_INDEX	0
 #define DEFAULT_TEMP		20 /* room temp in deg Celsius */
 
@@ -203,6 +207,8 @@ struct mxc_epdc_fb_data {
 	bool updates_active;
 	int pwrdown_delay;
 	unsigned long tce_prevent;
+	bool restrict_width; /* work around rev >=2.0 width and
+				stride restriction  */
 
 	/* FB elements related to PxP DMA */
 	struct completion pxp_tx_cmpl;
@@ -1941,10 +1947,10 @@ static int epdc_process_update(struct update_data_list *upd_data_list,
 	 * to copybuf in addition to the PxP structures */
 	mutex_lock(&fb_data->pxp_mutex);
 
-	if ((((width_unaligned || height_unaligned || input_unaligned) &&
+	if (((((width_unaligned || height_unaligned || input_unaligned) &&
 		(upd_desc_list->upd_data.waveform_mode == WAVEFORM_MODE_AUTO))
-		|| line_overflow) && (fb_data->rev < 20)) {
-
+		|| line_overflow) && (fb_data->rev < 20)) ||
+		fb_data->restrict_width) {
 		dev_dbg(fb_data->dev, "Copying update before processing.\n");
 
 		/* Update to reflect what the new source buffer will be */
@@ -2148,7 +2154,8 @@ static int epdc_process_update(struct update_data_list *upd_data_list,
 }
 
 static int epdc_submit_merge(struct update_desc_list *upd_desc_list,
-				struct update_desc_list *update_to_merge)
+				struct update_desc_list *update_to_merge,
+				struct mxc_epdc_fb_data *fb_data)
 {
 	struct mxcfb_update_data *a, *b;
 	struct mxcfb_rect *arect, *brect;
@@ -2206,6 +2213,19 @@ static int epdc_submit_merge(struct update_desc_list *upd_desc_list,
 			(arect->top + arect->height - combine.top) :
 			(brect->top + brect->height - combine.top);
 
+	/* Don't merge if combined width exceeds max width */
+	if (fb_data->restrict_width) {
+		u32 max_width = EPDC_V2_MAX_UPDATE_WIDTH;
+		u32 combined_width = combine.width;
+		if (fb_data->epdc_fb_var.rotate != FB_ROTATE_UR)
+			max_width -= EPDC_V2_ROTATION_ALIGNMENT;
+		if ((fb_data->epdc_fb_var.rotate == FB_ROTATE_CW) ||
+			(fb_data->epdc_fb_var.rotate == FB_ROTATE_CCW))
+			combined_width = combine.height;
+		if (combined_width > max_width)
+			return MERGE_FAIL;
+	}
+
 	*arect = combine;
 
 	/* Use flags of the later update */
@@ -2272,7 +2292,8 @@ static void epdc_submit_work_func(struct work_struct *work)
 				break;
 		} else {
 			switch (epdc_submit_merge(upd_data_list->update_desc,
-						next_update->update_desc)) {
+						next_update->update_desc,
+						fb_data)) {
 			case MERGE_OK:
 				dev_dbg(fb_data->dev,
 					"Update merged [collision]\n");
@@ -2342,7 +2363,7 @@ static void epdc_submit_work_func(struct work_struct *work)
 					break;
 			} else {
 				switch (epdc_submit_merge(upd_data_list->update_desc,
-						next_desc)) {
+						next_desc, fb_data)) {
 				case MERGE_OK:
 					dev_dbg(fb_data->dev,
 						"Update merged [queue]\n");
@@ -2389,7 +2410,8 @@ static void epdc_submit_work_func(struct work_struct *work)
 
 	if ((fb_data->epdc_fb_var.rotate == FB_ROTATE_UR) &&
 		(fb_data->epdc_fb_var.grayscale == GRAYSCALE_8BIT) &&
-		!is_transform && (fb_data->rev > 20)) {
+		!is_transform && (fb_data->rev > 20) &&
+		!fb_data->restrict_width) {
 
 		/* If needed, enable EPDC HW while ePxP is processing */
 		if ((fb_data->power_state == POWER_STATE_OFF)
@@ -2623,8 +2645,7 @@ static void epdc_submit_work_func(struct work_struct *work)
 	mutex_unlock(&fb_data->queue_mutex);
 }
 
-
-int mxc_epdc_fb_send_update(struct mxcfb_update_data *upd_data,
+static int mxc_epdc_fb_send_single_update(struct mxcfb_update_data *upd_data,
 				   struct fb_info *info)
 {
 	struct mxc_epdc_fb_data *fb_data = info ?
@@ -2919,6 +2940,63 @@ int mxc_epdc_fb_send_update(struct mxcfb_update_data *upd_data,
 	mutex_unlock(&fb_data->queue_mutex);
 	return 0;
 }
+
+int mxc_epdc_fb_send_update(struct mxcfb_update_data *upd_data,
+				   struct fb_info *info)
+{
+	struct mxc_epdc_fb_data *fb_data = info ?
+		(struct mxc_epdc_fb_data *)info:g_fb_data;
+
+	if (!fb_data->restrict_width) {
+		/* No width restriction, send entire update region */
+		return mxc_epdc_fb_send_single_update(upd_data, info);
+	} else {
+		int ret;
+		__u32 width, left;
+		__u32 marker;
+		__u32 *region_width, *region_left;
+		u32 max_upd_width = EPDC_V2_MAX_UPDATE_WIDTH;
+
+		/* Further restrict max width due to pxp rotation
+		  * alignment requirement
+		  */
+		if (fb_data->epdc_fb_var.rotate != FB_ROTATE_UR)
+			max_upd_width -= EPDC_V2_ROTATION_ALIGNMENT;
+
+		/* Select split of width or height based on rotation */
+		if ((fb_data->epdc_fb_var.rotate == FB_ROTATE_UR) ||
+			(fb_data->epdc_fb_var.rotate == FB_ROTATE_UD)) {
+			region_width = &upd_data->update_region.width;
+			region_left = &upd_data->update_region.left;
+		} else {
+			region_width = &upd_data->update_region.height;
+			region_left = &upd_data->update_region.top;
+		}
+
+		if (*region_width <= max_upd_width)
+			return mxc_epdc_fb_send_single_update(upd_data,	info);
+
+		width = *region_width;
+		left = *region_left;
+		marker = upd_data->update_marker;
+		upd_data->update_marker = 0;
+
+		do {
+			*region_width = max_upd_width;
+			*region_left = left;
+			ret = mxc_epdc_fb_send_single_update(upd_data, info);
+			if (ret)
+				return ret;
+			width -= max_upd_width;
+			left += max_upd_width;
+		} while (width > max_upd_width);
+
+		*region_width = width;
+		*region_left = left;
+		upd_data->update_marker = marker;
+		return mxc_epdc_fb_send_single_update(upd_data, info);
+	}
+}
 EXPORT_SYMBOL(mxc_epdc_fb_send_update);
 
 int mxc_epdc_fb_wait_update_complete(struct mxcfb_update_marker_data *marker_data,
@@ -4146,7 +4224,8 @@ static void mxc_epdc_fb_fw_handler(const struct firmware *fw,
 		&fb_data->info);
 	if (ret < 0)
 		dev_err(fb_data->dev,
-			"Wait for update complete failed.  Error = 0x%x", ret);
+			"Wait for initial update complete failed."
+			" Error = 0x%x", ret);
 }
 
 static int mxc_epdc_fb_init_hw(struct fb_info *info)
@@ -4487,6 +4566,8 @@ int __devinit mxc_epdc_fb_probe(struct platform_device *pdev)
 	} else {
 		fb_data->num_luts = EPDC_V2_NUM_LUTS;
 		fb_data->max_num_updates = EPDC_V2_MAX_NUM_UPDATES;
+		if (vmode->xres > EPDC_V2_MAX_UPDATE_WIDTH)
+			fb_data->restrict_width = true;
 	}
 	fb_data->max_num_buffers = EPDC_MAX_NUM_BUFFERS;