ENGR00120428 v4l2 output: jitter after blank/unblank fb

blank/unblank fb during v4l2 playback, unblank will cause current buffer
of display channel to be 1. This patch make the sequence of select
display buffer correct.

Signed-off-by: Jason Chen <b02280@freescale.com>

drivers/media/video/mxc/output/mxc_v4l2_output.c

@@ -246,6 +246,22 @@ static u32 bpp_to_fmt(struct fb_info *fbi)
 	return 0;
 }
 
+/*
+ * we are using double buffer for video playback, ipu need make
+ * sure current buffer should not be the same buffer of next display
+ * one.
+ */
+static int select_display_buffer(vout_data *vout, int next_buf)
+{
+	int ret = 0;
+
+	if (ipu_get_cur_buffer_idx(vout->display_ch, IPU_INPUT_BUFFER)
+			!= next_buf)
+		ret = ipu_select_buffer(vout->display_ch, IPU_INPUT_BUFFER,
+				next_buf);
+	return ret;
+}
+
 static void setup_next_buf_timer(vout_data *vout, int index)
 {
 	unsigned long timeout;
@@ -347,8 +363,7 @@ static void timer_work_func(struct work_struct *work)
 	}
 
 	if (vout->ic_bypass)
-		ret = ipu_select_buffer(vout->display_ch, IPU_INPUT_BUFFER,
-				vout->next_rdy_ipu_buf);
+		ret = select_display_buffer(vout, vout->next_rdy_ipu_buf);
 	else if (LOAD_3FIELDS(vout))
 		ret = ipu_select_multi_vdi_buffer(vout->next_rdy_ipu_buf);
 	else
@@ -580,8 +595,7 @@ static irqreturn_t mxc_v4l2out_work_irq_handler(int irq, void *dev_id)
 				vout->next_done_ipu_buf = !vout->next_done_ipu_buf;
 
 			} else /* right stripe is done, run display refresh */
-				ret = ipu_select_buffer(vout->display_ch, IPU_INPUT_BUFFER,
-								disp_buf_num);
+				select_display_buffer(vout, disp_buf_num);
 
 			vout->next_rdy_ipu_buf = !vout->next_rdy_ipu_buf;
 
@@ -609,8 +623,7 @@ static irqreturn_t mxc_v4l2out_work_irq_handler(int irq, void *dev_id)
 			vout->pp_split_buf_num = (vout->pp_split_buf_num + 1) & 3;
 		} else {
 			/* show to display */
-			ret = ipu_select_buffer(vout->display_ch, IPU_INPUT_BUFFER,
-					vout->next_done_ipu_buf);
+			select_display_buffer(vout, vout->next_done_ipu_buf);
 			ret += ipu_select_buffer(vout->display_input_ch, IPU_OUTPUT_BUFFER,
 					vout->next_done_ipu_buf);
 		}

drivers/mxc/ipu/ipu_common.c

@@ -1204,6 +1204,21 @@ void ipu_clear_buffer_ready(ipu_channel_t channel, ipu_buffer_t type,
 {
 	/*TODO*/
 }
+EXPORT_SYMBOL(ipu_clear_buffer_ready);
+
+uint32_t ipu_get_cur_buffer_idx(ipu_channel_t channel, ipu_buffer_t type)
+{
+	uint32_t reg, dma_chan;
+
+	dma_chan = channel_2_dma(channel, type);
+
+	reg = __raw_readl(IPU_CHA_CUR_BUF);
+	if (reg & (1UL << dma_chan))
+		return 1;
+	else
+		return 0;
+}
+EXPORT_SYMBOL(ipu_get_cur_buffer_idx);
 
 /*!
  * This function disables a logical channel.

drivers/mxc/ipu3/ipu_common.c

@@ -1788,6 +1788,7 @@ void ipu_clear_buffer_ready(ipu_channel_t channel, ipu_buffer_t type,
 	__raw_writel(0x0, IPU_GPR); /* write one to set */
 	spin_unlock_irqrestore(&ipu_lock, lock_flags);
 }
+EXPORT_SYMBOL(ipu_clear_buffer_ready);
 
 static irqreturn_t disable_chan_irq_handler(int irq, void *dev_id)
 {
@@ -2162,6 +2163,22 @@ void ipu_free_irq(uint32_t irq, void *dev_id)
 }
 EXPORT_SYMBOL(ipu_free_irq);
 
+uint32_t ipu_get_cur_buffer_idx(ipu_channel_t channel, ipu_buffer_t type)
+{
+	uint32_t reg, dma_chan;
+
+	dma_chan = channel_2_dma(channel, type);
+	if (!idma_is_valid(dma_chan))
+		return -EINVAL;
+
+	reg = __raw_readl(IPU_CHA_CUR_BUF(dma_chan/32));
+	if (reg & idma_mask(dma_chan))
+		return 1;
+	else
+		return 0;
+}
+EXPORT_SYMBOL(ipu_get_cur_buffer_idx);
+
 uint32_t _ipu_channel_status(ipu_channel_t channel)
 {
 	uint32_t stat = 0;

include/linux/ipu.h

@@ -897,6 +897,7 @@ int32_t ipu_unlink_channels(ipu_channel_t src_ch, ipu_channel_t dest_ch);
 int32_t ipu_is_channel_busy(ipu_channel_t channel);
 void ipu_clear_buffer_ready(ipu_channel_t channel, ipu_buffer_t type,
 		uint32_t bufNum);
+uint32_t ipu_get_cur_buffer_idx(ipu_channel_t channel, ipu_buffer_t type);
 int32_t ipu_enable_channel(ipu_channel_t channel);
 int32_t ipu_disable_channel(ipu_channel_t channel, bool wait_for_stop);
 int32_t ipu_swap_channel(ipu_channel_t from_ch, ipu_channel_t to_ch);