Whenever receiving an OVERRUN event or an end of frame, the driver stops currently ongoing DMA transfer since the DCMI stops sending data to dma. Not doing this would lead to having DMA & DCMI no more synchronized in term of expected data to be copied. Since this is done in irq handler context, it is not possible to make any call that would lead to scheduling hence dmaengine_terminate_sync are not possible. Since the dcmi driver is NOT using dma callbacks, it is possible thus to call instead dmaengine_terminate_async (aka without synchronize) and call again right after a new dmaengine_submit to setup again a new transfer. And since this is now a dmaengine_submit_async, there is no need to release the spinlock around calls to the dmaengine_submit_async.
Signed-off-by: Alain Volmat alain.volmat@foss.st.com --- drivers/media/platform/st/stm32/stm32-dcmi.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/drivers/media/platform/st/stm32/stm32-dcmi.c b/drivers/media/platform/st/stm32/stm32-dcmi.c index 06b66095844b..25e95ba2ca84 100644 --- a/drivers/media/platform/st/stm32/stm32-dcmi.c +++ b/drivers/media/platform/st/stm32/stm32-dcmi.c @@ -334,10 +334,8 @@ static void dcmi_process_frame(struct stm32_dcmi *dcmi) dcmi_buffer_done(dcmi, buf, 0, -EIO); }
- spin_unlock_irq(&dcmi->irqlock); /* Abort DMA operation */ - dmaengine_terminate_sync(dcmi->dma_chan); - spin_lock_irq(&dcmi->irqlock); + dmaengine_terminate_async(dcmi->dma_chan); }
static irqreturn_t dcmi_irq_thread(int irq, void *arg) @@ -355,10 +353,8 @@ static irqreturn_t dcmi_irq_thread(int irq, void *arg) if (dcmi->overrun_count > OVERRUN_ERROR_THRESHOLD) dcmi->errors_count++;
- spin_unlock_irq(&dcmi->irqlock); - dmaengine_terminate_sync(dcmi->dma_chan); + dmaengine_terminate_async(dcmi->dma_chan);
- spin_lock_irq(&dcmi->irqlock); if (dcmi_restart_capture(dcmi)) dev_err(dcmi->dev, "%s: Cannot restart capture\n", __func__); spin_unlock_irq(&dcmi->irqlock);