Hi Guennadi,
I understand you are probably quite busy right now but it would be
great if you could ack this patch. The sooner you merge it the sooner
I will start working on the cleanup series. I've got some time on my
hands now.
Thank you.
On 7 February 2012 11:14, Javier Martin <javier.mar...@vista-silicon.com> wrote:
> The way discard buffer was previously handled lead
> to possible races that made a buffer that was not
> yet ready to be overwritten by new video data. This
> is easily detected at 25fps just adding "#define DEBUG"
> to enable the "memset" check and seeing how the image
> is corrupted.
>
> A new "discard" queue and two discard buffers have
> been added to make them flow trough the pipeline
> of queues and thus provide suitable event ordering.
>
> Signed-off-by: Javier Martin <javier.mar...@vista-silicon.com>
> ---
> - Add proper locking to avoid races between IRQ and stop callbacks.
> - If a list is unexpectedly empty want the user and bail out.
>
> ---
> drivers/media/video/mx2_camera.c | 287
> +++++++++++++++++++++-----------------
> 1 files changed, 161 insertions(+), 126 deletions(-)
>
> diff --git a/drivers/media/video/mx2_camera.c
> b/drivers/media/video/mx2_camera.c
> index 35ab971..3880d24 100644
> --- a/drivers/media/video/mx2_camera.c
> +++ b/drivers/media/video/mx2_camera.c
> @@ -237,7 +237,8 @@ struct mx2_buffer {
> struct list_head queue;
> enum mx2_buffer_state state;
>
> - int bufnum;
> + int bufnum;
> + bool discard;
> };
>
> struct mx2_camera_dev {
> @@ -256,6 +257,7 @@ struct mx2_camera_dev {
>
> struct list_head capture;
> struct list_head active_bufs;
> + struct list_head discard;
>
> spinlock_t lock;
>
> @@ -268,6 +270,7 @@ struct mx2_camera_dev {
>
> u32 csicr1;
>
> + struct mx2_buffer buf_discard[2];
> void *discard_buffer;
> dma_addr_t discard_buffer_dma;
> size_t discard_size;
> @@ -329,6 +332,29 @@ static struct mx2_fmt_cfg *mx27_emma_prp_get_format(
> return &mx27_emma_prp_table[0];
> };
>
> +static void mx27_update_emma_buf(struct mx2_camera_dev *pcdev,
> + unsigned long phys, int bufnum)
> +{
> + struct mx2_fmt_cfg *prp = pcdev->emma_prp;
> +
> + if (prp->cfg.channel == 1) {
> + writel(phys, pcdev->base_emma +
> + PRP_DEST_RGB1_PTR + 4 * bufnum);
> + } else {
> + writel(phys, pcdev->base_emma +
> + PRP_DEST_Y_PTR - 0x14 * bufnum);
> + if (prp->out_fmt == V4L2_PIX_FMT_YUV420) {
> + u32 imgsize = pcdev->icd->user_height *
> + pcdev->icd->user_width;
> +
> + writel(phys + imgsize, pcdev->base_emma +
> + PRP_DEST_CB_PTR - 0x14 * bufnum);
> + writel(phys + ((5 * imgsize) / 4), pcdev->base_emma +
> + PRP_DEST_CR_PTR - 0x14 * bufnum);
> + }
> + }
> +}
> +
> static void mx2_camera_deactivate(struct mx2_camera_dev *pcdev)
> {
> unsigned long flags;
> @@ -377,7 +403,7 @@ static int mx2_camera_add_device(struct soc_camera_device
> *icd)
> writel(pcdev->csicr1, pcdev->base_csi + CSICR1);
>
> pcdev->icd = icd;
> - pcdev->frame_count = -1;
> + pcdev->frame_count = 0;
>
> dev_info(icd->parent, "Camera driver attached to camera %d\n",
> icd->devnum);
> @@ -397,13 +423,6 @@ static void mx2_camera_remove_device(struct
> soc_camera_device *icd)
>
> mx2_camera_deactivate(pcdev);
>
> - if (pcdev->discard_buffer) {
> - dma_free_coherent(ici->v4l2_dev.dev, pcdev->discard_size,
> - pcdev->discard_buffer,
> - pcdev->discard_buffer_dma);
> - pcdev->discard_buffer = NULL;
> - }
> -
> pcdev->icd = NULL;
> }
>
> @@ -640,7 +659,6 @@ static void mx2_videobuf_release(struct vb2_buffer *vb)
> */
>
> spin_lock_irqsave(&pcdev->lock, flags);
> - list_del_init(&buf->queue);
> if (cpu_is_mx25() && buf->state == MX2_STATE_ACTIVE) {
> if (pcdev->fb1_active == buf) {
> pcdev->csicr1 &= ~CSICR1_FB1_DMA_INTEN;
> @@ -656,6 +674,34 @@ static void mx2_videobuf_release(struct vb2_buffer *vb)
> spin_unlock_irqrestore(&pcdev->lock, flags);
> }
>
> +static void mx27_camera_emma_buf_init(struct soc_camera_device *icd,
> + int bytesperline)
> +{
> + struct soc_camera_host *ici =
> + to_soc_camera_host(icd->parent);
> + struct mx2_camera_dev *pcdev = ici->priv;
> + struct mx2_fmt_cfg *prp = pcdev->emma_prp;
> +
> + writel((icd->user_width << 16) | icd->user_height,
> + pcdev->base_emma + PRP_SRC_FRAME_SIZE);
> + writel(prp->cfg.src_pixel,
> + pcdev->base_emma + PRP_SRC_PIXEL_FORMAT_CNTL);
> + if (prp->cfg.channel == 1) {
> + writel((icd->user_width << 16) | icd->user_height,
> + pcdev->base_emma + PRP_CH1_OUT_IMAGE_SIZE);
> + writel(bytesperline,
> + pcdev->base_emma + PRP_DEST_CH1_LINE_STRIDE);
> + writel(prp->cfg.ch1_pixel,
> + pcdev->base_emma + PRP_CH1_PIXEL_FORMAT_CNTL);
> + } else { /* channel 2 */
> + writel((icd->user_width << 16) | icd->user_height,
> + pcdev->base_emma + PRP_CH2_OUT_IMAGE_SIZE);
> + }
> +
> + /* Enable interrupts */
> + writel(prp->cfg.irq_flags, pcdev->base_emma + PRP_INTR_CNTL);
> +}
> +
> static int mx2_start_streaming(struct vb2_queue *q, unsigned int count)
> {
> struct soc_camera_device *icd = soc_camera_from_vb2q(q);
> @@ -663,6 +709,10 @@ static int mx2_start_streaming(struct vb2_queue *q,
> unsigned int count)
> to_soc_camera_host(icd->parent);
> struct mx2_camera_dev *pcdev = ici->priv;
> struct mx2_fmt_cfg *prp = pcdev->emma_prp;
> + struct vb2_buffer *vb;
> + struct mx2_buffer *buf;
> + unsigned long phys;
> + int bytesperline;
>
> if (mx27_camera_emma(pcdev)) {
> unsigned long flags;
> @@ -670,6 +720,56 @@ static int mx2_start_streaming(struct vb2_queue *q,
> unsigned int count)
> return -EINVAL;
>
> spin_lock_irqsave(&pcdev->lock, flags);
> +
> + buf = list_entry(pcdev->capture.next,
> + struct mx2_buffer, queue);
> + buf->bufnum = 0;
> + vb = &buf->vb;
> + buf->state = MX2_STATE_ACTIVE;
> +
> + phys = vb2_dma_contig_plane_dma_addr(vb, 0);
> + mx27_update_emma_buf(pcdev, phys, buf->bufnum);
> + list_move_tail(pcdev->capture.next, &pcdev->active_bufs);
> +
> + buf = list_entry(pcdev->capture.next,
> + struct mx2_buffer, queue);
> + buf->bufnum = 1;
> + vb = &buf->vb;
> + buf->state = MX2_STATE_ACTIVE;
> +
> + phys = vb2_dma_contig_plane_dma_addr(vb, 0);
> + mx27_update_emma_buf(pcdev, phys, buf->bufnum);
> + list_move_tail(pcdev->capture.next, &pcdev->active_bufs);
> +
> + bytesperline = soc_mbus_bytes_per_line(icd->user_width,
> + icd->current_fmt->host_fmt);
> + if (bytesperline < 0)
> + return bytesperline;
> +
> + /*
> + * I didn't manage to properly enable/disable the prp
> + * on a per frame basis during running transfers,
> + * thus we allocate a buffer here and use it to
> + * discard frames when no buffer is available.
> + * Feel free to work on this ;)
> + */
> + pcdev->discard_size = icd->user_height * bytesperline;
> + pcdev->discard_buffer = dma_alloc_coherent(ici->v4l2_dev.dev,
> + pcdev->discard_size,
> &pcdev->discard_buffer_dma,
> + GFP_KERNEL);
> + if (!pcdev->discard_buffer)
> + return -ENOMEM;
> +
> + pcdev->buf_discard[0].discard = true;
> + list_add_tail(&pcdev->buf_discard[0].queue,
> + &pcdev->discard);
> +
> + pcdev->buf_discard[1].discard = true;
> + list_add_tail(&pcdev->buf_discard[1].queue,
> + &pcdev->discard);
> +
> + mx27_camera_emma_buf_init(icd, bytesperline);
> +
> if (prp->cfg.channel == 1) {
> writel(PRP_CNTL_CH1EN |
> PRP_CNTL_CSIEN |
> @@ -704,10 +804,12 @@ static int mx2_stop_streaming(struct vb2_queue *q)
> struct mx2_camera_dev *pcdev = ici->priv;
> struct mx2_fmt_cfg *prp = pcdev->emma_prp;
> unsigned long flags;
> + void *b;
> u32 cntl;
>
> - spin_lock_irqsave(&pcdev->lock, flags);
> if (mx27_camera_emma(pcdev)) {
> + spin_lock_irqsave(&pcdev->lock, flags);
> +
> cntl = readl(pcdev->base_emma + PRP_CNTL);
> if (prp->cfg.channel == 1) {
> writel(cntl & ~PRP_CNTL_CH1EN,
> @@ -716,8 +818,18 @@ static int mx2_stop_streaming(struct vb2_queue *q)
> writel(cntl & ~PRP_CNTL_CH2EN,
> pcdev->base_emma + PRP_CNTL);
> }
> + INIT_LIST_HEAD(&pcdev->capture);
> + INIT_LIST_HEAD(&pcdev->active_bufs);
> + INIT_LIST_HEAD(&pcdev->discard);
> +
> + b = pcdev->discard_buffer;
> + pcdev->discard_buffer = NULL;
> +
> + spin_unlock_irqrestore(&pcdev->lock, flags);
> +
> + dma_free_coherent(ici->v4l2_dev.dev,
> + pcdev->discard_size, b, pcdev->discard_buffer_dma);
> }
> - spin_unlock_irqrestore(&pcdev->lock, flags);
>
> return 0;
> }
> @@ -771,63 +883,6 @@ static int mx27_camera_emma_prp_reset(struct
> mx2_camera_dev *pcdev)
> return -ETIMEDOUT;
> }
>
> -static void mx27_camera_emma_buf_init(struct soc_camera_device *icd,
> - int bytesperline)
> -{
> - struct soc_camera_host *ici =
> - to_soc_camera_host(icd->parent);
> - struct mx2_camera_dev *pcdev = ici->priv;
> - struct mx2_fmt_cfg *prp = pcdev->emma_prp;
> - u32 imgsize = pcdev->icd->user_height * pcdev->icd->user_width;
> -
> - if (prp->cfg.channel == 1) {
> - writel(pcdev->discard_buffer_dma,
> - pcdev->base_emma + PRP_DEST_RGB1_PTR);
> - writel(pcdev->discard_buffer_dma,
> - pcdev->base_emma + PRP_DEST_RGB2_PTR);
> -
> - writel((icd->user_width << 16) | icd->user_height,
> - pcdev->base_emma + PRP_SRC_FRAME_SIZE);
> - writel((icd->user_width << 16) | icd->user_height,
> - pcdev->base_emma + PRP_CH1_OUT_IMAGE_SIZE);
> - writel(bytesperline,
> - pcdev->base_emma + PRP_DEST_CH1_LINE_STRIDE);
> - writel(prp->cfg.src_pixel,
> - pcdev->base_emma + PRP_SRC_PIXEL_FORMAT_CNTL);
> - writel(prp->cfg.ch1_pixel,
> - pcdev->base_emma + PRP_CH1_PIXEL_FORMAT_CNTL);
> - } else { /* channel 2 */
> - writel(pcdev->discard_buffer_dma,
> - pcdev->base_emma + PRP_DEST_Y_PTR);
> - writel(pcdev->discard_buffer_dma,
> - pcdev->base_emma + PRP_SOURCE_Y_PTR);
> -
> - if (prp->cfg.out_fmt == PRP_CNTL_CH2_OUT_YUV420) {
> - writel(pcdev->discard_buffer_dma + imgsize,
> - pcdev->base_emma + PRP_DEST_CB_PTR);
> - writel(pcdev->discard_buffer_dma + ((5 * imgsize) /
> 4),
> - pcdev->base_emma + PRP_DEST_CR_PTR);
> - writel(pcdev->discard_buffer_dma + imgsize,
> - pcdev->base_emma + PRP_SOURCE_CB_PTR);
> - writel(pcdev->discard_buffer_dma + ((5 * imgsize) /
> 4),
> - pcdev->base_emma + PRP_SOURCE_CR_PTR);
> - }
> -
> - writel((icd->user_width << 16) | icd->user_height,
> - pcdev->base_emma + PRP_SRC_FRAME_SIZE);
> -
> - writel((icd->user_width << 16) | icd->user_height,
> - pcdev->base_emma + PRP_CH2_OUT_IMAGE_SIZE);
> -
> - writel(prp->cfg.src_pixel,
> - pcdev->base_emma + PRP_SRC_PIXEL_FORMAT_CNTL);
> -
> - }
> -
> - /* Enable interrupts */
> - writel(prp->cfg.irq_flags, pcdev->base_emma + PRP_INTR_CNTL);
> -}
> -
> static int mx2_camera_set_bus_param(struct soc_camera_device *icd,
> __u32 pixfmt)
> {
> @@ -911,27 +966,6 @@ static int mx2_camera_set_bus_param(struct
> soc_camera_device *icd,
> ret = mx27_camera_emma_prp_reset(pcdev);
> if (ret)
> return ret;
> -
> - if (pcdev->discard_buffer)
> - dma_free_coherent(ici->v4l2_dev.dev,
> - pcdev->discard_size, pcdev->discard_buffer,
> - pcdev->discard_buffer_dma);
> -
> - /*
> - * I didn't manage to properly enable/disable the prp
> - * on a per frame basis during running transfers,
> - * thus we allocate a buffer here and use it to
> - * discard frames when no buffer is available.
> - * Feel free to work on this ;)
> - */
> - pcdev->discard_size = icd->user_height * bytesperline;
> - pcdev->discard_buffer = dma_alloc_coherent(ici->v4l2_dev.dev,
> - pcdev->discard_size,
> &pcdev->discard_buffer_dma,
> - GFP_KERNEL);
> - if (!pcdev->discard_buffer)
> - return -ENOMEM;
> -
> - mx27_camera_emma_buf_init(icd, bytesperline);
> } else if (cpu_is_mx25()) {
> writel((bytesperline * icd->user_height) >> 2,
> pcdev->base_csi + CSIRXCNT);
> @@ -1179,18 +1213,23 @@ static struct soc_camera_host_ops
> mx2_soc_camera_host_ops = {
> static void mx27_camera_frame_done_emma(struct mx2_camera_dev *pcdev,
> int bufnum)
> {
> - u32 imgsize = pcdev->icd->user_height * pcdev->icd->user_width;
> struct mx2_fmt_cfg *prp = pcdev->emma_prp;
> struct mx2_buffer *buf;
> struct vb2_buffer *vb;
> unsigned long phys;
>
> - if (!list_empty(&pcdev->active_bufs)) {
> - buf = list_entry(pcdev->active_bufs.next,
> - struct mx2_buffer, queue);
> + buf = list_entry(pcdev->active_bufs.next,
> + struct mx2_buffer, queue);
>
> - BUG_ON(buf->bufnum != bufnum);
> + BUG_ON(buf->bufnum != bufnum);
>
> + if (buf->discard) {
> + /*
> + * Discard buffer must not be returned to user space.
> + * Just return it to the discard queue.
> + */
> + list_move_tail(pcdev->active_bufs.next, &pcdev->discard);
> + } else {
> vb = &buf->vb;
> #ifdef DEBUG
> phys = vb2_dma_contig_plane_dma_addr(vb, 0);
> @@ -1225,29 +1264,25 @@ static void mx27_camera_frame_done_emma(struct
> mx2_camera_dev *pcdev,
> pcdev->frame_count++;
>
> if (list_empty(&pcdev->capture)) {
> - if (prp->cfg.channel == 1) {
> - writel(pcdev->discard_buffer_dma, pcdev->base_emma +
> - PRP_DEST_RGB1_PTR + 4 * bufnum);
> - } else {
> - writel(pcdev->discard_buffer_dma, pcdev->base_emma +
> - PRP_DEST_Y_PTR -
> - 0x14 * bufnum);
> - if (prp->out_fmt == V4L2_PIX_FMT_YUV420) {
> - writel(pcdev->discard_buffer_dma + imgsize,
> - pcdev->base_emma + PRP_DEST_CB_PTR -
> - 0x14 * bufnum);
> - writel(pcdev->discard_buffer_dma +
> - ((5 * imgsize) / 4), pcdev->base_emma +
> - PRP_DEST_CR_PTR - 0x14 * bufnum);
> - }
> + if (list_empty(&pcdev->discard)) {
> + dev_warn(pcdev->dev, "%s: trying to access empty
> discard list\n",
> + __func__);
> + return;
> }
> +
> + buf = list_entry(pcdev->discard.next,
> + struct mx2_buffer, queue);
> + buf->bufnum = bufnum;
> +
> + list_move_tail(pcdev->discard.next, &pcdev->active_bufs);
> + mx27_update_emma_buf(pcdev, pcdev->discard_buffer_dma,
> bufnum);
> return;
> }
>
> buf = list_entry(pcdev->capture.next,
> struct mx2_buffer, queue);
>
> - buf->bufnum = !bufnum;
> + buf->bufnum = bufnum;
>
> list_move_tail(pcdev->capture.next, &pcdev->active_bufs);
>
> @@ -1255,18 +1290,7 @@ static void mx27_camera_frame_done_emma(struct
> mx2_camera_dev *pcdev,
> buf->state = MX2_STATE_ACTIVE;
>
> phys = vb2_dma_contig_plane_dma_addr(vb, 0);
> - if (prp->cfg.channel == 1) {
> - writel(phys, pcdev->base_emma + PRP_DEST_RGB1_PTR + 4 *
> bufnum);
> - } else {
> - writel(phys, pcdev->base_emma +
> - PRP_DEST_Y_PTR - 0x14 * bufnum);
> - if (prp->cfg.out_fmt == PRP_CNTL_CH2_OUT_YUV420) {
> - writel(phys + imgsize, pcdev->base_emma +
> - PRP_DEST_CB_PTR - 0x14 * bufnum);
> - writel(phys + ((5 * imgsize) / 4), pcdev->base_emma +
> - PRP_DEST_CR_PTR - 0x14 * bufnum);
> - }
> - }
> + mx27_update_emma_buf(pcdev, phys, bufnum);
> }
>
> static irqreturn_t mx27_camera_emma_irq(int irq_emma, void *data)
> @@ -1274,6 +1298,15 @@ static irqreturn_t mx27_camera_emma_irq(int irq_emma,
> void *data)
> struct mx2_camera_dev *pcdev = data;
> unsigned int status = readl(pcdev->base_emma + PRP_INTRSTATUS);
> struct mx2_buffer *buf;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&pcdev->lock, flags);
> +
> + if (list_empty(&pcdev->active_bufs)) {
> + dev_warn(pcdev->dev, "%s: called while active list is
> empty\n",
> + __func__);
> + goto irq_ok;
> + }
>
> if (status & (1 << 7)) { /* overflow */
> u32 cntl;
> @@ -1290,9 +1323,8 @@ static irqreturn_t mx27_camera_emma_irq(int irq_emma,
> void *data)
> pcdev->base_emma + PRP_CNTL);
> writel(cntl, pcdev->base_emma + PRP_CNTL);
> }
> - if ((((status & (3 << 5)) == (3 << 5)) ||
> - ((status & (3 << 3)) == (3 << 3)))
> - && !list_empty(&pcdev->active_bufs)) {
> + if (((status & (3 << 5)) == (3 << 5)) ||
> + ((status & (3 << 3)) == (3 << 3))) {
> /*
> * Both buffers have triggered, process the one we're expecting
> * to first
> @@ -1307,6 +1339,8 @@ static irqreturn_t mx27_camera_emma_irq(int irq_emma,
> void *data)
> if ((status & (1 << 5)) || (status & (1 << 3)))
> mx27_camera_frame_done_emma(pcdev, 1);
>
> +irq_ok:
> + spin_unlock_irqrestore(&pcdev->lock, flags);
> writel(status, pcdev->base_emma + PRP_INTRSTATUS);
>
> return IRQ_HANDLED;
> @@ -1418,6 +1452,7 @@ static int __devinit mx2_camera_probe(struct
> platform_device *pdev)
>
> INIT_LIST_HEAD(&pcdev->capture);
> INIT_LIST_HEAD(&pcdev->active_bufs);
> + INIT_LIST_HEAD(&pcdev->discard);
> spin_lock_init(&pcdev->lock);
>
> /*
> --
> 1.7.0.4
>
--
Javier Martin
Vista Silicon S.L.
CDTUC - FASE C - Oficina S-345
Avda de los Castros s/n
39005- Santander. Cantabria. Spain
+34 942 25 32 60
www.vista-silicon.com
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