2019-05-29 21:47:28

by Dmitry Osipenko

Subject: [PATCH v1] dmaengine: tegra-apb: Error out if DMA_PREP_INTERRUPT flag is unset

Apparently driver was never tested with DMA_PREP_INTERRUPT flag being
unset since it completely disables interrupt handling instead of skipping
the callbacks invocations, hence putting channel into unusable state.

The flag is always set by all of kernel drivers that use APB DMA, so let's
error out in otherwise case for consistency. It won't be difficult to
support that case properly if ever will be needed.

Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma/tegra20-apb-dma.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index cf462b1abc0b..2c84a660ba36 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -988,8 +988,12 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
}

- if (flags & DMA_PREP_INTERRUPT)
+ if (flags & DMA_PREP_INTERRUPT) {
csr |= TEGRA_APBDMA_CSR_IE_EOC;
+ } else {
+ WARN_ON_ONCE(1);
+ return NULL;
+ }

apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;

@@ -1131,8 +1135,12 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
}

- if (flags & DMA_PREP_INTERRUPT)
+ if (flags & DMA_PREP_INTERRUPT) {
csr |= TEGRA_APBDMA_CSR_IE_EOC;
+ } else {
+ WARN_ON_ONCE(1);
+ return NULL;
+ }

apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;

--
2.21.0

2019-05-30 12:05:43

by Jon Hunter

Subject: Re: [PATCH v1] dmaengine: tegra-apb: Error out if DMA_PREP_INTERRUPT flag is unset

On 29/05/2019 22:43, Dmitry Osipenko wrote:
> Apparently driver was never tested with DMA_PREP_INTERRUPT flag being
> unset since it completely disables interrupt handling instead of skipping
> the callbacks invocations, hence putting channel into unusable state.
>
> The flag is always set by all of kernel drivers that use APB DMA, so let's
> error out in otherwise case for consistency. It won't be difficult to
> support that case properly if ever will be needed.
>
> Signed-off-by: Dmitry Osipenko <[email protected]>
> ---
> drivers/dma/tegra20-apb-dma.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index cf462b1abc0b..2c84a660ba36 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -988,8 +988,12 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
> csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> }
>
> - if (flags & DMA_PREP_INTERRUPT)
> + if (flags & DMA_PREP_INTERRUPT) {
> csr |= TEGRA_APBDMA_CSR_IE_EOC;
> + } else {
> + WARN_ON_ONCE(1);
> + return NULL;
> + }
>
> apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
>
> @@ -1131,8 +1135,12 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
> csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> }
>
> - if (flags & DMA_PREP_INTERRUPT)
> + if (flags & DMA_PREP_INTERRUPT) {
> csr |= TEGRA_APBDMA_CSR_IE_EOC;
> + } else {
> + WARN_ON_ONCE(1);
> + return NULL;
> + }
>
> apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;

Looks good to me.

Acked-by: Jon Hunter <[email protected]>

Cheers
Jon

--
nvpublic

2019-05-30 17:33:46

by Dmitry Osipenko

Subject: Re: [PATCH v1] dmaengine: tegra-apb: Error out if DMA_PREP_INTERRUPT flag is unset

30.05.2019 15:01, Jon Hunter пишет:
>
> On 29/05/2019 22:43, Dmitry Osipenko wrote:
>> Apparently driver was never tested with DMA_PREP_INTERRUPT flag being
>> unset since it completely disables interrupt handling instead of skipping
>> the callbacks invocations, hence putting channel into unusable state.
>>
>> The flag is always set by all of kernel drivers that use APB DMA, so let's
>> error out in otherwise case for consistency. It won't be difficult to
>> support that case properly if ever will be needed.
>>
>> Signed-off-by: Dmitry Osipenko <[email protected]>
>> ---
>> drivers/dma/tegra20-apb-dma.c | 12 ++++++++++--
>> 1 file changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
>> index cf462b1abc0b..2c84a660ba36 100644
>> --- a/drivers/dma/tegra20-apb-dma.c
>> +++ b/drivers/dma/tegra20-apb-dma.c
>> @@ -988,8 +988,12 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
>> csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
>> }
>>
>> - if (flags & DMA_PREP_INTERRUPT)
>> + if (flags & DMA_PREP_INTERRUPT) {
>> csr |= TEGRA_APBDMA_CSR_IE_EOC;
>> + } else {
>> + WARN_ON_ONCE(1);
>> + return NULL;
>> + }
>>
>> apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
>>
>> @@ -1131,8 +1135,12 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
>> csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
>> }
>>
>> - if (flags & DMA_PREP_INTERRUPT)
>> + if (flags & DMA_PREP_INTERRUPT) {
>> csr |= TEGRA_APBDMA_CSR_IE_EOC;
>> + } else {
>> + WARN_ON_ONCE(1);
>> + return NULL;
>> + }
>>
>> apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
>
> Looks good to me.
>
> Acked-by: Jon Hunter <[email protected]>
>
> Cheers
> Jon
>

Thanks

2019-06-04 12:22:51

by Vinod Koul

Subject: Re: [PATCH v1] dmaengine: tegra-apb: Error out if DMA_PREP_INTERRUPT flag is unset

On 30-05-19, 00:43, Dmitry Osipenko wrote:
> Apparently driver was never tested with DMA_PREP_INTERRUPT flag being
> unset since it completely disables interrupt handling instead of skipping
> the callbacks invocations, hence putting channel into unusable state.
>
> The flag is always set by all of kernel drivers that use APB DMA, so let's
> error out in otherwise case for consistency. It won't be difficult to
> support that case properly if ever will be needed.

Applied, thanks

--
~Vinod