V4L/DVB (7670): pxa-camera: handle FIFO overruns

FIFO overruns are not seldom on PXA camera interface FIFOs. Handle them by
dropping the corrupted frame, waiting for the next start-of-frame, and
restarting capture.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 39 insertions, 20 deletions

diff --git a/drivers/media/video/pxa_camera.c b/drivers/media/video/pxa_camera.c
index b999bda23c48..1dcfd9109c57 100644
--- a/drivers/media/video/pxa_camera.c
+++ b/drivers/media/video/pxa_camera.c
@@ -118,6 +118,7 @@ struct pxa_camera_dev {
         unsigned int            irq;
         void __iomem            *base;
 
+        int                     channels;
         unsigned int            dma_chans[3];
 
         struct pxacamera_platform_data *pdata;
@@ -398,14 +399,10 @@ static void pxa_videobuf_queue(struct videobuf_queue *vq,
         } else {
                 struct pxa_cam_dma *buf_dma;
                 struct pxa_cam_dma *act_dma;
-                int channels = 1;
                 int nents;
                 int i;
 
-                if (buf->fmt->fourcc == V4L2_PIX_FMT_YUV422P)
-                        channels = 3;
-
-                for (i = 0; i < channels; i++) {
+                for (i = 0; i < pcdev->channels; i++) {
                         buf_dma = &buf->dmas[i];
                         act_dma = &active->dmas[i];
                         nents = buf_dma->sglen;
@@ -445,20 +442,6 @@ static void pxa_videobuf_queue(struct videobuf_queue *vq,
 
                         DCSR(pcdev->dma_chans[i]) = DCSR_RUN;
                 }
-#ifdef DEBUG
-                if (CISR & (CISR_IFO_0 | CISR_IFO_1 | CISR_IFO_2)) {
-                        dev_warn(pcdev->dev, "FIFO overrun\n");
-                        for (i = 0; i < channels; i++)
-                                DDADR(pcdev->dma_chans[i]) =
-                                        pcdev->active->dmas[i].sg_dma;
-
-                        CICR0 &= ~CICR0_ENB;
-                        CIFR |= CIFR_RESET_F;
-                        for (i = 0; i < channels; i++)
-                                DCSR(pcdev->dma_chans[i]) = DCSR_RUN;
-                        CICR0 |= CICR0_ENB;
-                }
-#endif
         }
 
         spin_unlock_irqrestore(&pcdev->lock, flags);
@@ -522,7 +505,7 @@ static void pxa_camera_dma_irq(int channel, struct pxa_camera_dev *pcdev,
 {
         struct pxa_buffer *buf;
         unsigned long flags;
-        unsigned int status;
+        u32 status, camera_status, overrun;
         struct videobuf_buffer *vb;
 
         spin_lock_irqsave(&pcdev->lock, flags);
@@ -546,6 +529,25 @@ static void pxa_camera_dma_irq(int channel, struct pxa_camera_dev *pcdev,
                 goto out;
         }
 
+        camera_status = CISR;
+        overrun = CISR_IFO_0;
+        if (pcdev->channels == 3)
+                overrun |= CISR_IFO_1 | CISR_IFO_2;
+        if (camera_status & overrun) {
+                dev_dbg(pcdev->dev, "FIFO overrun! CISR: %x\n", camera_status);
+                /* Stop the Capture Interface */
+                CICR0 &= ~CICR0_ENB;
+                /* Stop DMA */
+                DCSR(channel) = 0;
+                /* Reset the FIFOs */
+                CIFR |= CIFR_RESET_F;
+                /* Enable End-Of-Frame Interrupt */
+                CICR0 &= ~CICR0_EOFM;
+                /* Restart the Capture Interface */
+                CICR0 |= CICR0_ENB;
+                goto out;
+        }
+
         vb = &pcdev->active->vb;
         buf = container_of(vb, struct pxa_buffer, vb);
         WARN_ON(buf->inwork || list_empty(&vb->queue));
@@ -670,7 +672,21 @@ static irqreturn_t pxa_camera_irq(int irq, void *data)
 
         dev_dbg(pcdev->dev, "Camera interrupt status 0x%x\n", status);
 
+        if (!status)
+                return IRQ_NONE;
+
         CISR = status;
+
+        if (status & CISR_EOF) {
+                int i;
+                for (i = 0; i < pcdev->channels; i++) {
+                        DDADR(pcdev->dma_chans[i]) =
+                                pcdev->active->dmas[i].sg_dma;
+                        DCSR(pcdev->dma_chans[i]) = DCSR_RUN;
+                }
+                CICR0 |= CICR0_EOFM;
+        }
+
         return IRQ_HANDLED;
 }
 
@@ -785,6 +801,8 @@ static int pxa_camera_set_bus_param(struct soc_camera_device *icd, __u32 pixfmt)
         if (!common_flags)
                 return -EINVAL;
 
+        pcdev->channels = 1;
+
         /* Make choises, based on platform preferences */
         if ((common_flags & SOCAM_HSYNC_ACTIVE_HIGH) &&
             (common_flags & SOCAM_HSYNC_ACTIVE_LOW)) {
@@ -855,6 +873,7 @@ static int pxa_camera_set_bus_param(struct soc_camera_device *icd, __u32 pixfmt)
 
         switch (pixfmt) {
         case V4L2_PIX_FMT_YUV422P:
+                pcdev->channels = 3;
                 cicr1 |= CICR1_YCBCR_F;
         case V4L2_PIX_FMT_YUYV:
                 cicr1 |= CICR1_COLOR_SP_VAL(2);