Revisit and fix DCMI buffers handling.
Hugues Fruchet (4):
media: stm32-dcmi: do not fall into error on buffer starvation
media: stm32-dcmi: return buffer in error state on dma error
media: stm32-dcmi: clarify state logic on buffer starvation
media: stm32-dcmi: revisit buffer list management
drivers/media/platform/stm32/stm32-dcmi.c | 80 ++++++++++++++++---------------
1 file changed, 41 insertions(+), 39 deletions(-)
--
1.9.1
Return silently instead of falling into error when running
out of available buffers when restarting capture.
Capture will be restarted when new buffers will be
provided by V4L2 client.
Signed-off-by: Hugues Fruchet <[email protected]>
---
drivers/media/platform/stm32/stm32-dcmi.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c
index b796334..a3fbfac 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -228,13 +228,10 @@ static int dcmi_restart_capture(struct stm32_dcmi *dcmi)
/* Restart a new DMA transfer with next buffer */
if (list_empty(&dcmi->buffers)) {
- dev_err(dcmi->dev, "%s: No more buffer queued, cannot capture buffer\n",
- __func__);
- dcmi->errors_count++;
+ dev_dbg(dcmi->dev, "Capture restart is deferred to next buffer queueing\n");
dcmi->active = NULL;
-
spin_unlock_irq(&dcmi->irqlock);
- return -EINVAL;
+ return 0;
}
dcmi->active = list_entry(dcmi->buffers.next,
--
1.9.1
Cleanup "active" field usage and enhance list management
to avoid exceptions when releasing buffers on error or
stopping streaming.
Signed-off-by: Hugues Fruchet <[email protected]>
---
drivers/media/platform/stm32/stm32-dcmi.c | 65 +++++++++++++++----------------
1 file changed, 31 insertions(+), 34 deletions(-)
diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c
index 93bb03a..581ded0 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -191,7 +191,7 @@ static inline void reg_clear(void __iomem *base, u32 reg, u32 mask)
reg_write(base, reg, reg_read(base, reg) & ~mask);
}
-static int dcmi_start_capture(struct stm32_dcmi *dcmi);
+static int dcmi_start_capture(struct stm32_dcmi *dcmi, struct dcmi_buf *buf);
static void dcmi_buffer_done(struct stm32_dcmi *dcmi,
struct dcmi_buf *buf,
@@ -203,6 +203,8 @@ static void dcmi_buffer_done(struct stm32_dcmi *dcmi,
if (!buf)
return;
+ list_del_init(&buf->list);
+
vbuf = &buf->vb;
vbuf->sequence = dcmi->sequence++;
@@ -220,6 +222,8 @@ static void dcmi_buffer_done(struct stm32_dcmi *dcmi,
static int dcmi_restart_capture(struct stm32_dcmi *dcmi)
{
+ struct dcmi_buf *buf;
+
spin_lock_irq(&dcmi->irqlock);
if (dcmi->state != RUNNING) {
@@ -230,19 +234,16 @@ static int dcmi_restart_capture(struct stm32_dcmi *dcmi)
/* Restart a new DMA transfer with next buffer */
if (list_empty(&dcmi->buffers)) {
dev_dbg(dcmi->dev, "Capture restart is deferred to next buffer queueing\n");
- dcmi->active = NULL;
dcmi->state = WAIT_FOR_BUFFER;
spin_unlock_irq(&dcmi->irqlock);
return 0;
}
-
- dcmi->active = list_entry(dcmi->buffers.next,
- struct dcmi_buf, list);
- list_del_init(&dcmi->active->list);
+ buf = list_entry(dcmi->buffers.next, struct dcmi_buf, list);
+ dcmi->active = buf;
spin_unlock_irq(&dcmi->irqlock);
- return dcmi_start_capture(dcmi);
+ return dcmi_start_capture(dcmi, buf);
}
static void dcmi_dma_callback(void *param)
@@ -252,6 +253,8 @@ static void dcmi_dma_callback(void *param)
enum dma_status status;
struct dcmi_buf *buf = dcmi->active;
+ spin_lock_irq(&dcmi->irqlock);
+
/* Check DMA status */
status = dmaengine_tx_status(dcmi->dma_chan, dcmi->dma_cookie, &state);
@@ -274,15 +277,19 @@ static void dcmi_dma_callback(void *param)
/* Return buffer to V4L2 */
dcmi_buffer_done(dcmi, buf, buf->size, 0);
+ spin_unlock_irq(&dcmi->irqlock);
+
/* Restart capture */
if (dcmi_restart_capture(dcmi))
dev_err(dcmi->dev, "%s: Cannot restart capture on DMA complete\n",
__func__);
- break;
+ return;
default:
dev_err(dcmi->dev, "%s: Received unknown status\n", __func__);
break;
}
+
+ spin_unlock_irq(&dcmi->irqlock);
}
static int dcmi_start_dma(struct stm32_dcmi *dcmi,
@@ -334,10 +341,9 @@ static int dcmi_start_dma(struct stm32_dcmi *dcmi,
return 0;
}
-static int dcmi_start_capture(struct stm32_dcmi *dcmi)
+static int dcmi_start_capture(struct stm32_dcmi *dcmi, struct dcmi_buf *buf)
{
int ret;
- struct dcmi_buf *buf = dcmi->active;
if (!buf)
return -EINVAL;
@@ -491,8 +497,6 @@ static int dcmi_queue_setup(struct vb2_queue *vq,
*nplanes = 1;
sizes[0] = size;
- dcmi->active = NULL;
-
dev_dbg(dcmi->dev, "Setup queue, count=%d, size=%d\n",
*nbuffers, size);
@@ -550,23 +554,24 @@ static void dcmi_buf_queue(struct vb2_buffer *vb)
spin_lock_irq(&dcmi->irqlock);
- dcmi->active = buf;
+ /* Enqueue to video buffers list */
+ list_add_tail(&buf->list, &dcmi->buffers);
if (dcmi->state == WAIT_FOR_BUFFER) {
dcmi->state = RUNNING;
+ dcmi->active = buf;
dev_dbg(dcmi->dev, "Starting capture on buffer[%d] queued\n",
buf->vb.vb2_buf.index);
spin_unlock_irq(&dcmi->irqlock);
- if (dcmi_start_capture(dcmi))
+ if (dcmi_start_capture(dcmi, buf))
dev_err(dcmi->dev, "%s: Cannot restart capture on overflow or error\n",
__func__);
- } else {
- /* Enqueue to video buffers list */
- list_add_tail(&buf->list, &dcmi->buffers);
- spin_unlock_irq(&dcmi->irqlock);
+ return;
}
+
+ spin_unlock_irq(&dcmi->irqlock);
}
static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
@@ -638,7 +643,6 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
dcmi->errors_count = 0;
dcmi->overrun_count = 0;
dcmi->buffers_count = 0;
- dcmi->active = NULL;
/*
* Start transfer if at least one buffer has been queued,
@@ -651,15 +655,15 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
return 0;
}
- dcmi->active = list_entry(dcmi->buffers.next, struct dcmi_buf, list);
- list_del_init(&dcmi->active->list);
-
- dev_dbg(dcmi->dev, "Start streaming, starting capture\n");
+ buf = list_entry(dcmi->buffers.next, struct dcmi_buf, list);
+ dcmi->active = buf;
dcmi->state = RUNNING;
+ dev_dbg(dcmi->dev, "Start streaming, starting capture\n");
+
spin_unlock_irq(&dcmi->irqlock);
- ret = dcmi_start_capture(dcmi);
+ ret = dcmi_start_capture(dcmi, buf);
if (ret) {
dev_err(dcmi->dev, "%s: Start streaming failed, cannot start capture\n",
__func__);
@@ -683,15 +687,11 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
* Return all buffers to vb2 in QUEUED state.
* This will give ownership back to userspace
*/
- if (dcmi->active) {
- buf = dcmi->active;
- vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_QUEUED);
- dcmi->active = NULL;
- }
list_for_each_entry_safe(buf, node, &dcmi->buffers, list) {
list_del_init(&buf->list);
vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_QUEUED);
}
+ dcmi->active = NULL;
spin_unlock_irq(&dcmi->irqlock);
return ret;
@@ -733,16 +733,13 @@ static void dcmi_stop_streaming(struct vb2_queue *vq)
}
/* Return all queued buffers to vb2 in ERROR state */
- if (dcmi->active) {
- buf = dcmi->active;
- vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
- dcmi->active = NULL;
- }
list_for_each_entry_safe(buf, node, &dcmi->buffers, list) {
list_del_init(&buf->list);
vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
}
+ dcmi->active = NULL;
+
spin_unlock_irq(&dcmi->irqlock);
/* Stop all pending DMA operations */
--
1.9.1
Return buffer to V4L2 in error state if DMA error occurs.
Signed-off-by: Hugues Fruchet <[email protected]>
---
drivers/media/platform/stm32/stm32-dcmi.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c
index a3fbfac..6ccf195 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -262,6 +262,9 @@ static void dcmi_dma_callback(void *param)
break;
case DMA_ERROR:
dev_err(dcmi->dev, "%s: Received DMA_ERROR\n", __func__);
+
+ /* Return buffer to V4L2 in error state */
+ dcmi_buffer_done(dcmi, buf, 0, -EIO);
break;
case DMA_COMPLETE:
dev_dbg(dcmi->dev, "%s: Received DMA_COMPLETE\n", __func__);
--
1.9.1
Introduce WAIT_FOR_BUFFER state instead of "active" field checking
to manage buffer starvation case.
Signed-off-by: Hugues Fruchet <[email protected]>
---
drivers/media/platform/stm32/stm32-dcmi.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c
index 6ccf195..93bb03a 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -85,6 +85,7 @@
enum state {
STOPPED = 0,
+ WAIT_FOR_BUFFER,
RUNNING,
STOPPING,
};
@@ -230,6 +231,7 @@ static int dcmi_restart_capture(struct stm32_dcmi *dcmi)
if (list_empty(&dcmi->buffers)) {
dev_dbg(dcmi->dev, "Capture restart is deferred to next buffer queueing\n");
dcmi->active = NULL;
+ dcmi->state = WAIT_FOR_BUFFER;
spin_unlock_irq(&dcmi->irqlock);
return 0;
}
@@ -548,9 +550,11 @@ static void dcmi_buf_queue(struct vb2_buffer *vb)
spin_lock_irq(&dcmi->irqlock);
- if (dcmi->state == RUNNING && !dcmi->active) {
dcmi->active = buf;
+ if (dcmi->state == WAIT_FOR_BUFFER) {
+ dcmi->state = RUNNING;
+
dev_dbg(dcmi->dev, "Starting capture on buffer[%d] queued\n",
buf->vb.vb2_buf.index);
@@ -630,8 +634,6 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
/* Enable dcmi */
reg_set(dcmi->regs, DCMI_CR, CR_ENABLE);
- dcmi->state = RUNNING;
-
dcmi->sequence = 0;
dcmi->errors_count = 0;
dcmi->overrun_count = 0;
@@ -644,6 +646,7 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
*/
if (list_empty(&dcmi->buffers)) {
dev_dbg(dcmi->dev, "Start streaming is deferred to next buffer queueing\n");
+ dcmi->state = WAIT_FOR_BUFFER;
spin_unlock_irq(&dcmi->irqlock);
return 0;
}
@@ -653,6 +656,8 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
dev_dbg(dcmi->dev, "Start streaming, starting capture\n");
+ dcmi->state = RUNNING;
+
spin_unlock_irq(&dcmi->irqlock);
ret = dcmi_start_capture(dcmi);
if (ret) {
--
1.9.1