[media] davinci: vpif_capture: fix start/stop streaming locking

Video capture subdevs may be over I2C and may sleep during xfer, so we
cannot do IRQ-disabled locking when calling the subdev.

The IRQ-disabled locking is meant to protect the DMA queue list
throughout the rest of the driver, so update the locking in
[start|stop]_streaming to protect just this list, and update the irqlock
comment to reflect what it actually protects.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/platform/davinci/vpif_capture.c b/drivers/media/platform/davinci/vpif_capture.c
index 54c4397..44f7027 100644 (file)
--- a/drivers/media/platform/davinci/vpif_capture.c
+++ b/drivers/media/platform/davinci/vpif_capture.c
@@ -175,8 +175,6 @@ static int vpif_start_streaming(struct vb2_queue *vq, unsigned int count)
        unsigned long addr, flags;
        int ret;
 
-       spin_lock_irqsave(&common->irqlock, flags);
-
        /* Initialize field_id */
        ch->field_id = 0;
 
@@ -207,6 +205,7 @@ static int vpif_start_streaming(struct vb2_queue *vq, unsigned int count)
        vpif_config_addr(ch, ret);
 
        /* Get the next frame from the buffer queue */
+       spin_lock_irqsave(&common->irqlock, flags);
        common->cur_frm = common->next_frm = list_entry(common->dma_queue.next,
                                    struct vpif_cap_buffer, list);
        /* Remove buffer from the buffer queue */
@@ -240,6 +239,7 @@ static int vpif_start_streaming(struct vb2_queue *vq, unsigned int count)
        return 0;
 
 err:
+       spin_lock_irqsave(&common->irqlock, flags);
        list_for_each_entry_safe(buf, tmp, &common->dma_queue, list) {
                list_del(&buf->list);
                vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_QUEUED);
@@ -283,7 +283,6 @@ static void vpif_stop_streaming(struct vb2_queue *vq)
                vpif_dbg(1, debug, "stream off failed in subdev\n");
 
        /* release all active buffers */
-       spin_lock_irqsave(&common->irqlock, flags);
        if (common->cur_frm == common->next_frm) {
                vb2_buffer_done(&common->cur_frm->vb.vb2_buf,
                                VB2_BUF_STATE_ERROR);
@@ -296,6 +295,7 @@ static void vpif_stop_streaming(struct vb2_queue *vq)
                                        VB2_BUF_STATE_ERROR);
        }
 
+       spin_lock_irqsave(&common->irqlock, flags);
        while (!list_empty(&common->dma_queue)) {
                common->next_frm = list_entry(common->dma_queue.next,
                                                struct vpif_cap_buffer, list);

diff --git a/drivers/media/platform/davinci/vpif_capture.h b/drivers/media/platform/davinci/vpif_capture.h
index e625d1c..cf494a5 100644 (file)
--- a/drivers/media/platform/davinci/vpif_capture.h
+++ b/drivers/media/platform/davinci/vpif_capture.h
@@ -63,7 +63,7 @@ struct common_obj {
        struct vb2_queue buffer_queue;
        /* Queue of filled frames */
        struct list_head dma_queue;
-       /* Used in video-buf */
+       /* Protects the dma_queue field */
        spinlock_t irqlock;
        /* lock used to access this structure */
        struct mutex lock;