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>

diff --git a/drivers/media/video/pxa_camera.c b/drivers/media/video/pxa_camera.c
index b999bda23c48194b07a223c8315c94b2b500d0c5..1dcfd9109c570ed76a2ce2154c294ecabf884c03 100644 (file)
--- 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);