[5/5] dmaengine: sprd: Add 'device_config' and 'device_prep_slave_sg' interfaces

[5/5] dmaengine: sprd: Add 'device_config' and 'device_prep_slave_sg' interfaces

[Baolin Wang]

This patch adds the 'device_config' and 'device_prep_slave_sg' interfaces
for users to configure DMA.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
 drivers/dma/sprd-dma.c |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index f8038de..c923fb0 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -869,6 +869,52 @@ static int sprd_dma_config(struct dma_chan *chan, struct sprd_dma_desc *sdesc,
 	return vchan_tx_prep(&schan->vc, &sdesc->vd, flags);
 }
 
+static struct dma_async_tx_descriptor *
+sprd_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+		       unsigned int sglen, enum dma_transfer_direction dir,
+		       unsigned long flags, void *context)
+{
+	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
+	struct sprd_dma_config *slave_cfg = &schan->slave_cfg;
+	struct sprd_dma_desc *sdesc;
+	struct scatterlist *sg;
+	int ret, i;
+
+	/* TODO: now we only support one sg for each DMA configuration. */
+	if (!is_slave_direction(slave_cfg->config.direction) || sglen > 1)
+		return NULL;
+
+	sdesc = kzalloc(sizeof(*sdesc), GFP_NOWAIT);
+	if (!sdesc)
+		return NULL;
+
+	for_each_sg(sgl, sg, sglen, i) {
+		if (slave_cfg->config.direction == DMA_MEM_TO_DEV)
+			slave_cfg->config.src_addr = sg_dma_address(sg);
+		else
+			slave_cfg->config.dst_addr = sg_dma_address(sg);
+	}
+
+	ret = sprd_dma_config(chan, sdesc, slave_cfg);
+	if (ret) {
+		kfree(sdesc);
+		return NULL;
+	}
+
+	return vchan_tx_prep(&schan->vc, &sdesc->vd, flags);
+}
+
+static int sprd_dma_slave_config(struct dma_chan *chan,
+				 struct dma_slave_config *config)
+{
+	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
+	struct sprd_dma_config *slave_cfg =
+		container_of(config, struct sprd_dma_config, config);
+
+	memcpy(&schan->slave_cfg, slave_cfg, sizeof(*slave_cfg));
+	return 0;
+}
+
 static int sprd_dma_pause(struct dma_chan *chan)
 {
 	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
@@ -996,6 +1042,8 @@ static int sprd_dma_probe(struct platform_device *pdev)
 	sdev->dma_dev.device_tx_status = sprd_dma_tx_status;
 	sdev->dma_dev.device_issue_pending = sprd_dma_issue_pending;
 	sdev->dma_dev.device_prep_dma_memcpy = sprd_dma_prep_dma_memcpy;
+	sdev->dma_dev.device_prep_slave_sg = sprd_dma_prep_slave_sg;
+	sdev->dma_dev.device_config = sprd_dma_slave_config;
 	sdev->dma_dev.device_pause = sprd_dma_pause;
 	sdev->dma_dev.device_resume = sprd_dma_resume;
 	sdev->dma_dev.device_terminate_all = sprd_dma_terminate_all;

[5/5] dmaengine: sprd: Add 'device_config' and 'device_prep_slave_sg' interfaces

[Vinod Koul]

On Tue, Apr 10, 2018 at 03:46:07PM +0800, Baolin Wang wrote:
> This patch adds the 'device_config' and 'device_prep_slave_sg' interfaces
> for users to configure DMA.
> 
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
>  drivers/dma/sprd-dma.c |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 48 insertions(+)
> 
> diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
> index f8038de..c923fb0 100644
> --- a/drivers/dma/sprd-dma.c
> +++ b/drivers/dma/sprd-dma.c
> @@ -869,6 +869,52 @@ static int sprd_dma_config(struct dma_chan *chan, struct sprd_dma_desc *sdesc,
>  	return vchan_tx_prep(&schan->vc, &sdesc->vd, flags);
>  }
>  
> +static struct dma_async_tx_descriptor *
> +sprd_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> +		       unsigned int sglen, enum dma_transfer_direction dir,
> +		       unsigned long flags, void *context)
> +{
> +	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
> +	struct sprd_dma_config *slave_cfg = &schan->slave_cfg;
> +	struct sprd_dma_desc *sdesc;
> +	struct scatterlist *sg;
> +	int ret, i;
> +
> +	/* TODO: now we only support one sg for each DMA configuration. */
> +	if (!is_slave_direction(slave_cfg->config.direction) || sglen > 1)

the slave direction check seems wrong to me. .device_config shall give you
dma_slave_config. You should check here if dir passed is slave or not. If
you want to check parameters in slave_config then please use .device_config

> +		return NULL;
> +
> +	sdesc = kzalloc(sizeof(*sdesc), GFP_NOWAIT);
> +	if (!sdesc)
> +		return NULL;
> +
> +	for_each_sg(sgl, sg, sglen, i) {
> +		if (slave_cfg->config.direction == DMA_MEM_TO_DEV)
> +			slave_cfg->config.src_addr = sg_dma_address(sg);

Nope slave_config specifies peripheral address and not memory one passed here

[5/5] dmaengine: sprd: Add 'device_config' and 'device_prep_slave_sg' interfaces

[Baolin Wang]

Hi Vinod,

On 11 April 2018 at 17:40, Vinod Koul <vinod.koul@intel.com> wrote:
> On Tue, Apr 10, 2018 at 03:46:07PM +0800, Baolin Wang wrote:
>> This patch adds the 'device_config' and 'device_prep_slave_sg' interfaces
>> for users to configure DMA.
>>
>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
>> ---
>>  drivers/dma/sprd-dma.c |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 48 insertions(+)
>>
>> diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
>> index f8038de..c923fb0 100644
>> --- a/drivers/dma/sprd-dma.c
>> +++ b/drivers/dma/sprd-dma.c
>> @@ -869,6 +869,52 @@ static int sprd_dma_config(struct dma_chan *chan, struct sprd_dma_desc *sdesc,
>>       return vchan_tx_prep(&schan->vc, &sdesc->vd, flags);
>>  }
>>
>> +static struct dma_async_tx_descriptor *
>> +sprd_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
>> +                    unsigned int sglen, enum dma_transfer_direction dir,
>> +                    unsigned long flags, void *context)
>> +{
>> +     struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
>> +     struct sprd_dma_config *slave_cfg = &schan->slave_cfg;
>> +     struct sprd_dma_desc *sdesc;
>> +     struct scatterlist *sg;
>> +     int ret, i;
>> +
>> +     /* TODO: now we only support one sg for each DMA configuration. */
>> +     if (!is_slave_direction(slave_cfg->config.direction) || sglen > 1)
>
> the slave direction check seems wrong to me. .device_config shall give you
> dma_slave_config. You should check here if dir passed is slave or not. If
> you want to check parameters in slave_config then please use .device_config

Correct. Sorry I missed this and I will fix it in next version.

>
>> +             return NULL;
>> +
>> +     sdesc = kzalloc(sizeof(*sdesc), GFP_NOWAIT);
>> +     if (!sdesc)
>> +             return NULL;
>> +
>> +     for_each_sg(sgl, sg, sglen, i) {
>> +             if (slave_cfg->config.direction == DMA_MEM_TO_DEV)
>> +                     slave_cfg->config.src_addr = sg_dma_address(sg);
>
> Nope slave_config specifies peripheral address and not memory one passed here

OK. Thanks for your comments.

[5/5] dmaengine: sprd: Add 'device_config' and 'device_prep_slave_sg' interfaces

[Lars-Peter Clausen]

On 04/10/2018 09:46 AM, Baolin Wang wrote:
[...]
> +static int sprd_dma_slave_config(struct dma_chan *chan,
> +				 struct dma_slave_config *config)
> +{
> +	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
> +	struct sprd_dma_config *slave_cfg =
> +		container_of(config, struct sprd_dma_config, config);
> +

Please do not overload standard API with custom semantics. This makes the
driver incompatible to the API and negates the whole idea of having a common
API. E.g. this will crash when somebody passes a normal dma_slave_config
struct to this function.

> +	memcpy(&schan->slave_cfg, slave_cfg, sizeof(*slave_cfg));
> +	return 0;
> +}
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[5/5] dmaengine: sprd: Add 'device_config' and 'device_prep_slave_sg' interfaces

[Baolin Wang]

On 17 April 2018 at 18:45, Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 04/10/2018 09:46 AM, Baolin Wang wrote:
> [...]
>> +static int sprd_dma_slave_config(struct dma_chan *chan,
>> +                              struct dma_slave_config *config)
>> +{
>> +     struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
>> +     struct sprd_dma_config *slave_cfg =
>> +             container_of(config, struct sprd_dma_config, config);
>> +
>
> Please do not overload standard API with custom semantics. This makes the
> driver incompatible to the API and negates the whole idea of having a common
> API. E.g. this will crash when somebody passes a normal dma_slave_config
> struct to this function.
>

Yes, we have discussed with Vinod how to use 'dma_slave_config' to
reach our requirements. Thanks for your comments.