04.02.2020 14:52, Jon Hunter пишет:
>
> On 02/02/2020 22:28, Dmitry Osipenko wrote:
>> The pending_sg_req list can't ever be empty because:
>>
>> 1. If it was empty, then handle_cont_sngl_cycle_dma_done() shall crash
>> before of handle_continuous_head_request() invocation.
>>
>> 2. The handle_cont_sngl_cycle_dma_done() can't happen after stopping DMA.
>
> By this you mean calling terminate_all?
Yes, and also the handle_continuous_head_request() itself because it
stops DMA on error, which clears interrupt status, and thus, ISR handle
returns IRQ_NONE without handling next interrupt.
>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>> ---
>> drivers/dma/tegra20-apb-dma.c | 6 ------
>> 1 file changed, 6 deletions(-)
>>
>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
>> index 62d181bd5e62..c7dc27ef1856 100644
>> --- a/drivers/dma/tegra20-apb-dma.c
>> +++ b/drivers/dma/tegra20-apb-dma.c
>> @@ -564,12 +564,6 @@ static bool handle_continuous_head_request(struct tegra_dma_channel *tdc,
>> {
>> struct tegra_dma_sg_req *hsgreq;
>>
>> - if (list_empty(&tdc->pending_sg_req)) {
>> - dev_err(tdc2dev(tdc), "DMA is running without req\n");
>> - tegra_dma_stop(tdc);
>> - return false;
>> - }
>> -
>> /*
>> * Check that head req on list should be in flight.
>> * If it is not in flight then abort transfer as
>>
>
> There is also a list_empty() check in tdc_configure_next_head_desc()
> which is also redundant and could be removed here as well.
Good catch :) I'll squash all these list_empty() removals into a single
patch.
