MLK-16536-15 video: fbdev: dcss: improve cfifo wrapping handling

After changing the strategy to 'flush cfifo once per frame',
the cfifo wrapping handling should also be changed accordingly.
Now, when it is found that the cfifo has no enough room from 'in'
to the buffer end to hold the current commit, the 'commit_cfifo'
will cancel this commit and flush the cfifo workqueue before
restart the commit again.

Signed-off-by: Fancy Fang <chen.fang@nxp.com>
Reviewed-by: Robby Cai <robby.cai@nxp.com>

1 files changed, 45 insertions, 12 deletions

diff --git a/drivers/video/fbdev/mxc/imx_dcss.c b/drivers/video/fbdev/mxc/imx_dcss.c
index dcbfa70b86ea..290d42edf270 100644
--- a/drivers/video/fbdev/mxc/imx_dcss.c
+++ b/drivers/video/fbdev/mxc/imx_dcss.c
@@ -538,6 +538,8 @@ static int dcss_ioctl(struct fb_info *fbi, unsigned int cmd,
 		      unsigned long arg);
 static int vcount_compare(unsigned long vcount,
 			  struct vsync_info *vinfo);
+static int dcss_wait_for_vsync(unsigned long crtc,
+			       struct dcss_info *info);
 
 static struct fb_ops dcss_ops = {
 	.owner = THIS_MODULE,
@@ -2252,6 +2254,10 @@ static void dcss_ctxld_config(struct work_struct *work)
 	dsb_len = cc->sb_data_len + cc->db_data_len;
 	esize = kfifo_esize(&cfifo->fifo);
 
+	/* NOOP cc */
+	if (!cc->sb_data_len && !cc->db_data_len)
+		goto free_cc;
+
 	sg_init_table(cfifo->sgl, cfifo->sgl_num);
 	nsgl = kfifo_dma_out_prepare(&cfifo->fifo, cfifo->sgl,
 				     cfifo->sgl_num, dsb_len);
@@ -2296,6 +2302,7 @@ static void dcss_ctxld_config(struct work_struct *work)
 		(cc->sb_data_len + cc->db_data_len) * esize);
 	ctxld_fifo_info_print(cfifo);
 
+free_cc:
 	kfree(cc);
 
 	dev_dbg(&pdev->dev, "finish ctxld config\n");
@@ -2444,6 +2451,15 @@ static int defer_flush_cfifo(struct ctxld_fifo *cfifo)
 
 static int finish_cfifo(struct ctxld_fifo *cfifo)
 {
+	int ret;
+	struct dcss_info *info;
+
+	info = container_of(cfifo, struct dcss_info, cfifo);
+
+	ret = dcss_wait_for_vsync(0, info);
+	if (ret)
+		return ret;
+
 	flush_workqueue(cfifo->ctxld_wq);
 
 	return 0;
@@ -2453,9 +2469,7 @@ static int commit_cfifo(uint32_t channel,
 			struct dcss_info *info,
 			struct ctxld_commit *cc)
 {
-	int ret = 0;
 	uint32_t commit_size;
-	struct platform_device *pdev = info->pdev;
 	struct dcss_channels *chans;
 	struct dcss_channel_info *chan_info;
 	struct ctxld_fifo *cfifo;
@@ -2467,17 +2481,17 @@ static int commit_cfifo(uint32_t channel,
 	cb = &chan_info->cb;
 	commit_size = cb->sb_data_len + cb->db_data_len;
 
-restart:
 	spin_lock(&cfifo->cqueue.lock);
 
 	if (unlikely(atomic_read(&info->flush) == 1)) {
-		ret = wait_event_interruptible_exclusive_locked(cfifo->cqueue,
+		/* cancel this commit and restart it later */
+		release_cc(cc);
+
+		wait_event_interruptible_exclusive_locked(cfifo->cqueue,
 						atomic_read(&info->flush));
-		if (ret == -ERESTARTSYS) {
-			dev_info(&pdev->dev, "wait fifo flush is interrupted\n");
-			spin_unlock(&cfifo->cqueue.lock);
-			goto restart;
-		}
+
+		spin_unlock(&cfifo->cqueue.lock);
+		return -ERESTARTSYS;
 	} else {
 		if (unlikely(waitqueue_active(&cfifo->cqueue)))
 			wake_up_locked(&cfifo->cqueue);
@@ -2486,13 +2500,23 @@ restart:
 	if (unlikely(commit_size > kfifo_to_end_len(&cfifo->fifo))) {
 		atomic_set(&info->flush, 1);
 		spin_unlock(&cfifo->cqueue.lock);
+
+		/* cancel this commit and restart it later */
+		release_cc(cc);
+
 		/* Wait fifo flush empty to avoid fifo wrap */
 		finish_cfifo(cfifo);
+
 		spin_lock(&cfifo->cqueue.lock);
+
 		atomic_set(&info->flush, 0);
 		kfifo_reset(&cfifo->fifo);
 		if (waitqueue_active(&cfifo->cqueue))
 			wake_up_locked(&cfifo->cqueue);
+
+		spin_unlock(&cfifo->cqueue.lock);
+
+		return -ERESTART;
 	}
 
 	copy_data_to_cfifo(cfifo, cb, cc);
@@ -2730,13 +2754,16 @@ static int dcss_set_par(struct fb_info *fbi)
 		goto fail;
 
 #if USE_CTXLD
+restart:
 	cc = obtain_cc(fb_node, info);
 	if (IS_ERR(cc)) {
 		ret = PTR_ERR(cc);
 		goto fail;
 	}
 
-	commit_cfifo(fb_node, info, cc);
+	ret = commit_cfifo(fb_node, info, cc);
+	if (ret == -ERESTART)
+		goto restart;
 
 	release_cc(cc);
 #endif
@@ -2811,13 +2838,16 @@ static int dcss_blank(int blank, struct fb_info *fbi)
 	dcss_channel_blank(blank, cinfo);
 
 #if USE_CTXLD
+restart:
 	cc = obtain_cc(fb_node, info);
 	if (IS_ERR(cc)) {
 		ret = PTR_ERR(cc);
 		goto fail;
 	}
 
-	commit_cfifo(fb_node, info, cc);
+	ret = commit_cfifo(fb_node, info, cc);
+	if (ret == -ERESTART)
+		goto restart;
 
 	release_cc(cc);
 #endif
@@ -2879,13 +2909,16 @@ static int dcss_pan_display(struct fb_var_screeninfo *var,
 	}
 
 #if USE_CTXLD
+restart:
 	cc = obtain_cc(fb_node, info);
 	if (IS_ERR(cc)) {
 		ret = PTR_ERR(cc);
 		goto fail;
 	}
 
-	commit_cfifo(fbi->node, info, cc);
+	ret = commit_cfifo(fb_node, info, cc);
+	if (ret == -ERESTART)
+		goto restart;
 
 	release_cc(cc);
 #endif