dmaengine: tegra-apb: Support non-flow controlled slave configuration

Message ID 20171003223838.31834-1-digetx@gmail.com
State New
Headers show
Series
  • dmaengine: tegra-apb: Support non-flow controlled slave configuration
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Commit Message

Dmitry Osipenko Oct. 3, 2017, 10:38 p.m.
This allows DMA client to issue a non-flow controlled TX. In particular
it is needed for the fuse driver that reads fuse registers using APBDMA
to workaround a HW bug that results in hang when CPU and DMA perform
simultaneous access to fuse peripheral.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/dma/tegra20-apb-dma.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

Comments

Jon Hunter Oct. 5, 2017, 12:20 p.m. | #1
On 03/10/17 23:38, Dmitry Osipenko wrote:
> This allows DMA client to issue a non-flow controlled TX. In particular
> it is needed for the fuse driver that reads fuse registers using APBDMA
> to workaround a HW bug that results in hang when CPU and DMA perform
> simultaneous access to fuse peripheral.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/dma/tegra20-apb-dma.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index b9d75a54c896..a177039713a7 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -353,7 +353,8 @@ static int tegra_dma_slave_config(struct dma_chan *dc,
>  	}
>  
>  	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
> -	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID) {
> +	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID &&
> +	    sconfig->device_fc) {
>  		if (sconfig->slave_id > TEGRA_APBDMA_CSR_REQ_SEL_MASK)
>  			return -EINVAL;
>  		tdc->slave_id = sconfig->slave_id;
> @@ -970,8 +971,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
>  					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
>  	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
>  
> -	csr |= TEGRA_APBDMA_CSR_ONCE | TEGRA_APBDMA_CSR_FLOW;
> -	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> +	csr |= TEGRA_APBDMA_CSR_ONCE ;
> +
> +	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
> +		csr |= TEGRA_APBDMA_CSR_FLOW;
> +		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> +	}
> +
>  	if (flags & DMA_PREP_INTERRUPT)
>  		csr |= TEGRA_APBDMA_CSR_IE_EOC;
>  
> @@ -1110,10 +1116,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
>  					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
>  	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
>  
> -	csr |= TEGRA_APBDMA_CSR_FLOW;
> +	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
> +		csr |= TEGRA_APBDMA_CSR_FLOW;
> +		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> +	}
> +
>  	if (flags & DMA_PREP_INTERRUPT)
>  		csr |= TEGRA_APBDMA_CSR_IE_EOC;
> -	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
>  
>  	apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
>  

Reviewed-by: Jon Hunter <jonathanh@nvidia.com>

Cheers
Jon
Vinod Koul Oct. 12, 2017, 4:53 p.m. | #2
On Wed, Oct 04, 2017 at 01:38:38AM +0300, Dmitry Osipenko wrote:
> This allows DMA client to issue a non-flow controlled TX. In particular
> it is needed for the fuse driver that reads fuse registers using APBDMA
> to workaround a HW bug that results in hang when CPU and DMA perform
> simultaneous access to fuse peripheral.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/dma/tegra20-apb-dma.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index b9d75a54c896..a177039713a7 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -353,7 +353,8 @@ static int tegra_dma_slave_config(struct dma_chan *dc,
>  	}
>  
>  	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
> -	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID) {
> +	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID &&
> +	    sconfig->device_fc) {
>  		if (sconfig->slave_id > TEGRA_APBDMA_CSR_REQ_SEL_MASK)
>  			return -EINVAL;
>  		tdc->slave_id = sconfig->slave_id;
> @@ -970,8 +971,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
>  					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
>  	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
>  
> -	csr |= TEGRA_APBDMA_CSR_ONCE | TEGRA_APBDMA_CSR_FLOW;
> -	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> +	csr |= TEGRA_APBDMA_CSR_ONCE ;
				    ^^^
Checkpatch should have complained here, no space before ; please

> +
> +	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
> +		csr |= TEGRA_APBDMA_CSR_FLOW;
> +		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> +	}
> +
>  	if (flags & DMA_PREP_INTERRUPT)
>  		csr |= TEGRA_APBDMA_CSR_IE_EOC;
>  
> @@ -1110,10 +1116,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
>  					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
>  	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
>  
> -	csr |= TEGRA_APBDMA_CSR_FLOW;
> +	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
> +		csr |= TEGRA_APBDMA_CSR_FLOW;
> +		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> +	}
> +
>  	if (flags & DMA_PREP_INTERRUPT)
>  		csr |= TEGRA_APBDMA_CSR_IE_EOC;
> -	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
>  
>  	apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
>  
> -- 
> 2.14.1
> 
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Dmitry Osipenko Oct. 12, 2017, 5:35 p.m. | #3
On 12.10.2017 19:53, Vinod Koul wrote:
> On Wed, Oct 04, 2017 at 01:38:38AM +0300, Dmitry Osipenko wrote:
>> This allows DMA client to issue a non-flow controlled TX. In particular
>> it is needed for the fuse driver that reads fuse registers using APBDMA
>> to workaround a HW bug that results in hang when CPU and DMA perform
>> simultaneous access to fuse peripheral.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>>  drivers/dma/tegra20-apb-dma.c | 19 ++++++++++++++-----
>>  1 file changed, 14 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
>> index b9d75a54c896..a177039713a7 100644
>> --- a/drivers/dma/tegra20-apb-dma.c
>> +++ b/drivers/dma/tegra20-apb-dma.c
>> @@ -353,7 +353,8 @@ static int tegra_dma_slave_config(struct dma_chan *dc,
>>  	}
>>  
>>  	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
>> -	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID) {
>> +	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID &&
>> +	    sconfig->device_fc) {
>>  		if (sconfig->slave_id > TEGRA_APBDMA_CSR_REQ_SEL_MASK)
>>  			return -EINVAL;
>>  		tdc->slave_id = sconfig->slave_id;
>> @@ -970,8 +971,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
>>  					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
>>  	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
>>  
>> -	csr |= TEGRA_APBDMA_CSR_ONCE | TEGRA_APBDMA_CSR_FLOW;
>> -	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
>> +	csr |= TEGRA_APBDMA_CSR_ONCE ;
> 				    ^^^
> Checkpatch should have complained here, no space before ; please
> 

Yep, sorry.

>> +
>> +	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
>> +		csr |= TEGRA_APBDMA_CSR_FLOW;
>> +		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
>> +	}
>> +
>>  	if (flags & DMA_PREP_INTERRUPT)
>>  		csr |= TEGRA_APBDMA_CSR_IE_EOC;
>>  
>> @@ -1110,10 +1116,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
>>  					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
>>  	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
>>  
>> -	csr |= TEGRA_APBDMA_CSR_FLOW;
>> +	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
>> +		csr |= TEGRA_APBDMA_CSR_FLOW;
>> +		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
>> +	}
>> +
>>  	if (flags & DMA_PREP_INTERRUPT)
>>  		csr |= TEGRA_APBDMA_CSR_IE_EOC;
>> -	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
>>  
>>  	apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
>>  
>> -- 
>> 2.14.1
>>

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Patch

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index b9d75a54c896..a177039713a7 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -353,7 +353,8 @@  static int tegra_dma_slave_config(struct dma_chan *dc,
 	}
 
 	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
-	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID) {
+	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID &&
+	    sconfig->device_fc) {
 		if (sconfig->slave_id > TEGRA_APBDMA_CSR_REQ_SEL_MASK)
 			return -EINVAL;
 		tdc->slave_id = sconfig->slave_id;
@@ -970,8 +971,13 @@  static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
 					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
 	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
 
-	csr |= TEGRA_APBDMA_CSR_ONCE | TEGRA_APBDMA_CSR_FLOW;
-	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+	csr |= TEGRA_APBDMA_CSR_ONCE ;
+
+	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
+		csr |= TEGRA_APBDMA_CSR_FLOW;
+		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+	}
+
 	if (flags & DMA_PREP_INTERRUPT)
 		csr |= TEGRA_APBDMA_CSR_IE_EOC;
 
@@ -1110,10 +1116,13 @@  static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
 					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
 	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
 
-	csr |= TEGRA_APBDMA_CSR_FLOW;
+	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
+		csr |= TEGRA_APBDMA_CSR_FLOW;
+		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+	}
+
 	if (flags & DMA_PREP_INTERRUPT)
 		csr |= TEGRA_APBDMA_CSR_IE_EOC;
-	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
 
 	apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;