ENGR00238237-1 mx6sl: csi/v4l: fix camera picture flickering issue

Flickering issue happens when there's no buffer to be processed(e.g., the
pace of QBUF is much slower than DQBUF). The cause is the hardware is using
double buffering, while the driver has no good protection at above case and
thus the CSI will fill the buffer not in the right order. The way to fix is
refining the output of the working_q buffer list, that is, if there's no buffer
to be processed then output to a dummy buffer.

Another important change is to only do DMA reflash operation when SOF is
detected in streamon. Remove this operation is CSI interrupt handler because
it violates to the SPEC (only do DMA reflash before DMA is enabled but NOT at
the time or after DMA's enabled).

Signed-off-by: LiGang <b41990@freescale.com>
Signed-off-by: Robby Cai <R63905@freescale.com>
(cherry picked from commit 0c4584763fa44b01a2f48198fa27c9206a116164)

3 files changed, 105 insertions, 80 deletions

diff --git a/drivers/media/video/mxc/capture/csi_v4l2_capture.c b/drivers/media/video/mxc/capture/csi_v4l2_capture.c
index 53f35d487b21..bcfbe09d18b4 100644
--- a/drivers/media/video/mxc/capture/csi_v4l2_capture.c
+++ b/drivers/media/video/mxc/capture/csi_v4l2_capture.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2009-2012 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2009-2013 Freescale Semiconductor, Inc. All Rights Reserved.
  */
 
 /*
@@ -274,44 +274,43 @@ static void camera_callback(u32 mask, void *dev)
 
 	spin_lock(&cam->queue_int_lock);
 	spin_lock(&cam->dqueue_int_lock);
-	if (list_empty(&cam->working_q)) {
-		pr_debug("v4l2 capture: %s: "
-				"working queue empty\n", __func__);
-		spin_unlock(&cam->dqueue_int_lock);
-		spin_unlock(&cam->queue_int_lock);
-		return;
-	}
-
-	done_frame =
-		list_entry(cam->working_q.next, struct mxc_v4l_frame, queue);
-	if (done_frame->buffer.flags & V4L2_BUF_FLAG_QUEUED) {
-		done_frame->buffer.flags |= V4L2_BUF_FLAG_DONE;
-		done_frame->buffer.flags &= ~V4L2_BUF_FLAG_QUEUED;
-		if (list_empty(&cam->ready_q)) {
-			cam->skip_frame++;
+	if (!list_empty(&cam->working_q)) {
+		done_frame = list_entry(cam->working_q.next,
+				struct mxc_v4l_frame, queue);
+
+		if (done_frame->csi_buf_num != cam->ping_pong_csi)
+			goto next;
+
+		if (done_frame->buffer.flags & V4L2_BUF_FLAG_QUEUED) {
+			done_frame->buffer.flags |= V4L2_BUF_FLAG_DONE;
+			done_frame->buffer.flags &= ~V4L2_BUF_FLAG_QUEUED;
+
+			/* Added to the done queue */
+			list_del(cam->working_q.next);
+			list_add_tail(&done_frame->queue, &cam->done_q);
+			cam->enc_counter++;
+			wake_up_interruptible(&cam->enc_queue);
 		} else {
-			ready_frame = list_entry(cam->ready_q.next,
-						 struct mxc_v4l_frame, queue);
-			list_del(cam->ready_q.next);
-			list_add_tail(&ready_frame->queue, &cam->working_q);
-
-			if (cam->ping_pong_csi == 1) {
-				__raw_writel(cam->frame[ready_frame->index].
-					     paddress, CSI_CSIDMASA_FB1);
-			} else {
-				__raw_writel(cam->frame[ready_frame->index].
-					     paddress, CSI_CSIDMASA_FB2);
-			}
+			pr_err("ERROR: v4l2 capture: %s: "
+					"buffer not queued\n", __func__);
 		}
+	}
 
-		/* Added to the done queue */
-		list_del(cam->working_q.next);
-		list_add_tail(&done_frame->queue, &cam->done_q);
-		cam->enc_counter++;
-		wake_up_interruptible(&cam->enc_queue);
+next:
+	if (!list_empty(&cam->ready_q)) {
+		ready_frame = list_entry(cam->ready_q.next,
+					 struct mxc_v4l_frame, queue);
+		list_del(cam->ready_q.next);
+		list_add_tail(&ready_frame->queue, &cam->working_q);
+
+		__raw_writel(ready_frame->paddress,
+			cam->ping_pong_csi == 1 ? CSI_CSIDMASA_FB1 :
+						  CSI_CSIDMASA_FB2);
+		ready_frame->csi_buf_num = cam->ping_pong_csi;
 	} else {
-		pr_err("ERROR: v4l2 capture: %s: "
-				"buffer not queued\n", __func__);
+		__raw_writel(cam->dummy_frame.paddress,
+			cam->ping_pong_csi == 1 ? CSI_CSIDMASA_FB1 :
+						  CSI_CSIDMASA_FB2);
 	}
 	spin_unlock(&cam->dqueue_int_lock);
 	spin_unlock(&cam->queue_int_lock);
@@ -331,7 +330,7 @@ static int csi_cap_image(cam_data *cam)
 	unsigned int value;
 
 	value = __raw_readl(CSI_CSICR3);
-	__raw_writel(value | BIT_DMA_REFLASH_RFF | BIT_FRMCNT_RST, CSI_CSICR3);
+	__raw_writel(value | BIT_FRMCNT_RST, CSI_CSICR3);
 	value = __raw_readl(CSI_CSISR);
 	__raw_writel(value, CSI_CSISR);
 
@@ -364,6 +363,13 @@ static int csi_free_frame_buf(cam_data *cam)
 		}
 	}
 
+	if (cam->dummy_frame.vaddress != 0) {
+		dma_free_coherent(0, cam->dummy_frame.buffer.length,
+				  cam->dummy_frame.vaddress,
+				  cam->dummy_frame.paddress);
+		cam->dummy_frame.vaddress = 0;
+	}
+
 	return 0;
 }
 
@@ -403,6 +409,7 @@ static int csi_allocate_frame_buf(cam_data *cam, int count)
 		cam->frame[i].buffer.memory = V4L2_MEMORY_MMAP;
 		cam->frame[i].buffer.m.offset = cam->frame[i].paddress;
 		cam->frame[i].index = i;
+		cam->frame[i].csi_buf_num = 0;
 	}
 
 	return 0;
@@ -424,7 +431,6 @@ static void csi_free_frames(cam_data *cam)
 	for (i = 0; i < FRAME_NUM; i++)
 		cam->frame[i].buffer.flags = V4L2_BUF_FLAG_MAPPED;
 
-	cam->skip_frame = 0;
 	INIT_LIST_HEAD(&cam->ready_q);
 	INIT_LIST_HEAD(&cam->working_q);
 	INIT_LIST_HEAD(&cam->done_q);
@@ -508,7 +514,9 @@ static inline int valid_mode(u32 palette)
 static int csi_streamon(cam_data *cam)
 {
 	struct mxc_v4l_frame *frame;
-	unsigned long lock_flags;
+	unsigned long flags;
+	unsigned long val;
+	int timeout, timeout2;
 
 	pr_debug("In MVC: %s\n", __func__);
 
@@ -517,37 +525,81 @@ static int csi_streamon(cam_data *cam)
 				__func__);
 		return -1;
 	}
+	cam->dummy_frame.vaddress = dma_alloc_coherent(0,
+			       PAGE_ALIGN(cam->v2f.fmt.pix.sizeimage),
+			       &cam->dummy_frame.paddress,
+			       GFP_DMA | GFP_KERNEL);
+	if (cam->dummy_frame.vaddress == 0) {
+		pr_err("ERROR: v4l2 capture: Allocate dummy frame "
+		       "failed.\n");
+		return -ENOBUFS;
+	}
+	cam->dummy_frame.buffer.type = V4L2_BUF_TYPE_PRIVATE;
+	cam->dummy_frame.buffer.length =
+	    PAGE_ALIGN(cam->v2f.fmt.pix.sizeimage);
+	cam->dummy_frame.buffer.m.offset = cam->dummy_frame.paddress;
 
-	spin_lock_irqsave(&cam->queue_int_lock, lock_flags);
+	spin_lock_irqsave(&cam->queue_int_lock, flags);
 	/* move the frame from readyq to workingq */
 	if (list_empty(&cam->ready_q)) {
 		pr_err("ERROR: v4l2 capture: %s: "
 				"ready_q queue empty\n", __func__);
-		spin_unlock_irqrestore(&cam->queue_int_lock, lock_flags);
+		spin_unlock_irqrestore(&cam->queue_int_lock, flags);
 		return -1;
 	}
 	frame = list_entry(cam->ready_q.next, struct mxc_v4l_frame, queue);
 	list_del(cam->ready_q.next);
 	list_add_tail(&frame->queue, &cam->working_q);
-	__raw_writel(cam->frame[frame->index].paddress, CSI_CSIDMASA_FB1);
+	__raw_writel(frame->paddress, CSI_CSIDMASA_FB1);
+	frame->csi_buf_num = 1;
 
 	if (list_empty(&cam->ready_q)) {
 		pr_err("ERROR: v4l2 capture: %s: "
 				"ready_q queue empty\n", __func__);
-		spin_unlock_irqrestore(&cam->queue_int_lock, lock_flags);
+		spin_unlock_irqrestore(&cam->queue_int_lock, flags);
 		return -1;
 	}
 	frame = list_entry(cam->ready_q.next, struct mxc_v4l_frame, queue);
 	list_del(cam->ready_q.next);
 	list_add_tail(&frame->queue, &cam->working_q);
-	__raw_writel(cam->frame[frame->index].paddress, CSI_CSIDMASA_FB2);
-	spin_unlock_irqrestore(&cam->queue_int_lock, lock_flags);
+	__raw_writel(frame->paddress, CSI_CSIDMASA_FB2);
+	frame->csi_buf_num = 2;
+	spin_unlock_irqrestore(&cam->queue_int_lock, flags);
 
 	cam->capture_pid = current->pid;
 	cam->capture_on = true;
 	csi_cap_image(cam);
-	csi_enable_int(1);
-	csi_dmareq_rff_enable();
+
+	local_irq_save(flags);
+	for (timeout = 1000000; timeout > 0; timeout--) {
+		if (__raw_readl(CSI_CSISR) & BIT_SOF_INT) {
+			val = __raw_readl(CSI_CSICR3);
+			__raw_writel(val | BIT_DMA_REFLASH_RFF, CSI_CSICR3);
+			for (timeout2 = 1000000; timeout2 > 0; timeout2--) {
+				if (__raw_readl(CSI_CSICR3) &
+					BIT_DMA_REFLASH_RFF)
+					cpu_relax();
+				else
+					break;
+			}
+			if (timeout2 <= 0) {
+				pr_err("timeout when wait for reflash done.\n");
+				local_irq_restore(flags);
+				return -ETIME;
+			}
+
+			csi_dmareq_rff_enable();
+			csi_enable_int(1);
+			break;
+		} else
+			cpu_relax();
+	}
+	if (timeout <= 0) {
+		pr_err("timeout when wait for SOF\n");
+		local_irq_restore(flags);
+		return -ETIME;
+	}
+	local_irq_restore(flags);
 
 	return 0;
 }
@@ -561,8 +613,6 @@ static int csi_streamon(cam_data *cam)
  */
 static int csi_streamoff(cam_data *cam)
 {
-	unsigned int cr3;
-
 	pr_debug("In MVC: %s\n", __func__);
 
 	if (cam->capture_on == false)
@@ -575,8 +625,6 @@ static int csi_streamoff(cam_data *cam)
 	/* set CSI_CSIDMASA_FB1 and CSI_CSIDMASA_FB2 to default value */
 	__raw_writel(0, CSI_CSIDMASA_FB1);
 	__raw_writel(0, CSI_CSIDMASA_FB2);
-	cr3 = __raw_readl(CSI_CSICR3);
-	__raw_writel(cr3 | BIT_DMA_REFLASH_RFF, CSI_CSICR3);
 
 	csi_free_frames(cam);
 	csi_free_frame_buf(cam);
@@ -960,7 +1008,6 @@ static int csi_v4l_open(struct file *file)
 					 cam->low_power == false);
 
 		cam->enc_counter = 0;
-		cam->skip_frame = 0;
 		INIT_LIST_HEAD(&cam->ready_q);
 		INIT_LIST_HEAD(&cam->working_q);
 		INIT_LIST_HEAD(&cam->done_q);
@@ -1263,22 +1310,7 @@ static long csi_v4l_do_ioctl(struct file *file,
 		if ((cam->frame[index].buffer.flags & 0x7) ==
 				V4L2_BUF_FLAG_MAPPED) {
 			cam->frame[index].buffer.flags |= V4L2_BUF_FLAG_QUEUED;
-			if (cam->skip_frame > 0) {
-				list_add_tail(&cam->frame[index].queue,
-					      &cam->working_q);
-				cam->skip_frame = 0;
-
-				if (cam->ping_pong_csi == 1) {
-					__raw_writel(cam->frame[index].paddress,
-						     CSI_CSIDMASA_FB1);
-				} else {
-					__raw_writel(cam->frame[index].paddress,
-						     CSI_CSIDMASA_FB2);
-				}
-			} else {
-				list_add_tail(&cam->frame[index].queue,
-					      &cam->ready_q);
-			}
+			list_add_tail(&cam->frame[index].queue, &cam->ready_q);
 		} else if (cam->frame[index].buffer.flags &
 				V4L2_BUF_FLAG_QUEUED) {
 			pr_err("ERROR: v4l2 capture: VIDIOC_QBUF: "
@@ -1507,7 +1539,6 @@ static void init_camera_struct(cam_data *cam)
 	cam->streamparm.parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
 	cam->overlay_on = false;
 	cam->capture_on = false;
-	cam->skip_frame = 0;
 	cam->v4l2_fb.flags = V4L2_FBUF_FLAG_OVERLAY;
 
 	cam->v2f.fmt.pix.sizeimage = 480 * 640 * 2;
diff --git a/drivers/media/video/mxc/capture/fsl_csi.c b/drivers/media/video/mxc/capture/fsl_csi.c
index ede69b814b1b..5368b57c7a61 100644
--- a/drivers/media/video/mxc/capture/fsl_csi.c
+++ b/drivers/media/video/mxc/capture/fsl_csi.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2009-2012 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2009-2013 Freescale Semiconductor, Inc. All Rights Reserved.
  */
 
 /*
@@ -45,17 +45,9 @@ static irqreturn_t csi_irq_handler(int irq, void *data)
 {
 	cam_data *cam = (cam_data *) data;
 	unsigned long status = __raw_readl(CSI_CSISR);
-	unsigned long cr3 = __raw_readl(CSI_CSICR3);
-	unsigned int frame_count = (cr3 >> 16) & 0xFFFF;
 
 	__raw_writel(status, CSI_CSISR);
 
-	if (status & BIT_SOF_INT) {
-		/* reflash the embeded DMA controller */
-		if (frame_count % 2 == 1)
-			__raw_writel(cr3 | BIT_DMA_REFLASH_RFF, CSI_CSICR3);
-	}
-
 	if (status & BIT_HRESP_ERR_INT)
 		pr_warning("Hresponse error is detected.\n");
 
diff --git a/drivers/media/video/mxc/capture/mxc_v4l2_capture.h b/drivers/media/video/mxc/capture/mxc_v4l2_capture.h
index d2efbe8453b2..1431ef919a1c 100644
--- a/drivers/media/video/mxc/capture/mxc_v4l2_capture.h
+++ b/drivers/media/video/mxc/capture/mxc_v4l2_capture.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2004-2012 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2004-2013 Freescale Semiconductor, Inc. All Rights Reserved.
  */
 
 /*
@@ -56,7 +56,10 @@ struct mxc_v4l_frame {
 	struct v4l2_buffer buffer;
 	struct list_head queue;
 	int index;
-	int ipu_buf_num;
+	union {
+		int ipu_buf_num;
+		int csi_buf_num;
+	};
 };
 
 /* Only for old version.  Will go away soon. */
@@ -119,7 +122,6 @@ typedef struct _cam_data {
 	spinlock_t dqueue_int_lock;
 	struct mxc_v4l_frame frame[FRAME_NUM];
 	struct mxc_v4l_frame dummy_frame;
-	int skip_frame;
 	wait_queue_head_t enc_queue;
 	int enc_counter;
 	dma_addr_t rot_enc_bufs[2];