[PATCH 3/3] ARM: S3C64XX: Stop and flush requests on freeing

[PATCH 3/3] ARM: S3C64XX: Stop and flush requests on freeing

[Maurus Cuelenaere]

When a DMA channel is freed, its pending requests should be flushed and the
channel should be halted. This patch ensures that happens.

Signed-off-by: Maurus Cuelenaere <mcuelenaere@gmail.com>
---
 arch/arm/mach-s3c64xx/dma.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-s3c64xx/dma.c b/arch/arm/mach-s3c64xx/dma.c
index 1fd9d0c..e1f22af 100644
--- a/arch/arm/mach-s3c64xx/dma.c
+++ b/arch/arm/mach-s3c64xx/dma.c
@@ -560,7 +560,8 @@ int s3c2410_dma_free(unsigned int channel, struct s3c2410_dma_client *client)
 		       channel, chan->client, client);
 	}
 
-	/* sort out stopping and freeing the channel */
+	s3c64xx_dma_flush(chan);
+	s3c64xx_dma_stop(chan);
 
 
 	chan->client = NULL;
-- 
1.7.0.4

[PATCH 3/3] ARM: S3C64XX: Stop and flush requests on freeing

[Jassi Brar]

On Mon, May 31, 2010 at 8:34 PM, Maurus Cuelenaere
<mcuelenaere@gmail.com> wrote:
> When a DMA channel is freed, its pending requests should be flushed and the
> channel should be halted. This patch ensures that happens.
>
> Signed-off-by: Maurus Cuelenaere <mcuelenaere@gmail.com>
> ---
> ?arch/arm/mach-s3c64xx/dma.c | ? ?3 ++-
> ?1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/mach-s3c64xx/dma.c b/arch/arm/mach-s3c64xx/dma.c
> index 1fd9d0c..e1f22af 100644
> --- a/arch/arm/mach-s3c64xx/dma.c
> +++ b/arch/arm/mach-s3c64xx/dma.c
> @@ -560,7 +560,8 @@ int s3c2410_dma_free(unsigned int channel, struct s3c2410_dma_client *client)
> ? ? ? ? ? ? ? ? ? ? ? channel, chan->client, client);
> ? ? ? ?}
>
> - ? ? ? /* sort out stopping and freeing the channel */
> + ? ? ? s3c64xx_dma_flush(chan);
> + ? ? ? s3c64xx_dma_stop(chan);

I think, the order should be reverted.

[PATCH 3/3] ARM: S3C64XX: Stop and flush requests on freeing

[Jassi Brar]

On Sun, Aug 15, 2010 at 10:28 PM, Jassi Brar <jassisinghbrar@gmail.com> wrote:
> On Mon, May 31, 2010 at 8:34 PM, Maurus Cuelenaere
> <mcuelenaere@gmail.com> wrote:
>> When a DMA channel is freed, its pending requests should be flushed and the
>> channel should be halted. This patch ensures that happens.
>>
>> Signed-off-by: Maurus Cuelenaere <mcuelenaere@gmail.com>
>> ---
>> ?arch/arm/mach-s3c64xx/dma.c | ? ?3 ++-
>> ?1 files changed, 2 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/arm/mach-s3c64xx/dma.c b/arch/arm/mach-s3c64xx/dma.c
>> index 1fd9d0c..e1f22af 100644
>> --- a/arch/arm/mach-s3c64xx/dma.c
>> +++ b/arch/arm/mach-s3c64xx/dma.c
>> @@ -560,7 +560,8 @@ int s3c2410_dma_free(unsigned int channel, struct s3c2410_dma_client *client)
>> ? ? ? ? ? ? ? ? ? ? ? channel, chan->client, client);
>> ? ? ? ?}
>>
>> - ? ? ? /* sort out stopping and freeing the channel */
>> + ? ? ? s3c64xx_dma_flush(chan);
>> + ? ? ? s3c64xx_dma_stop(chan);
>
> I think, the order should be reverted.

Though it's a matter of S3C DMA API spec.
Shouldn't the client be made to explicitly do S3C2410_DMAOP_FLUSH
a pending req before freeing the channel? If so, the patch may not be needed.

[PATCH 3/3] ARM: S3C64XX: Stop and flush requests on freeing

[Maurus Cuelenaere]

 Op 15-08-10 15:36, Jassi Brar schreef:
> On Sun, Aug 15, 2010 at 10:28 PM, Jassi Brar <jassisinghbrar@gmail.com> wrote:
>> On Mon, May 31, 2010 at 8:34 PM, Maurus Cuelenaere
>> <mcuelenaere@gmail.com> wrote:
>>> When a DMA channel is freed, its pending requests should be flushed and the
>>> channel should be halted. This patch ensures that happens.
>>>
>>> Signed-off-by: Maurus Cuelenaere <mcuelenaere@gmail.com>
>>> ---
>>>  arch/arm/mach-s3c64xx/dma.c |    3 ++-
>>>  1 files changed, 2 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/arch/arm/mach-s3c64xx/dma.c b/arch/arm/mach-s3c64xx/dma.c
>>> index 1fd9d0c..e1f22af 100644
>>> --- a/arch/arm/mach-s3c64xx/dma.c
>>> +++ b/arch/arm/mach-s3c64xx/dma.c
>>> @@ -560,7 +560,8 @@ int s3c2410_dma_free(unsigned int channel, struct s3c2410_dma_client *client)
>>>                       channel, chan->client, client);
>>>        }
>>>
>>> -       /* sort out stopping and freeing the channel */
>>> +       s3c64xx_dma_flush(chan);
>>> +       s3c64xx_dma_stop(chan);
>> I think, the order should be reverted.

You're probably right.

> Though it's a matter of S3C DMA API spec.
> Shouldn't the client be made to explicitly do S3C2410_DMAOP_FLUSH
> a pending req before freeing the channel? If so, the patch may not be needed.

I can't find anything about the client needing to flush the request itself.

Documentation/arm/Samsung-S3C24XX/DMA.txt doesn't mention anything regarding it
and the comment above s3c2410_dma_free() says "release the given channel back to
the system, will stop and flush any outstanding transfers, and ensure the
channel is ready for the next claimant."


-- 
Maurus Cuelenaere

[PATCH 3/3] ARM: S3C64XX: Stop and flush requests on freeing

[Maurus Cuelenaere]

When a DMA channel is freed, its pending requests should be flushed and the
channel should be halted. This patch ensures that happens.

Signed-off-by: Maurus Cuelenaere <mcuelenaere@gmail.com>
---
 arch/arm/mach-s3c64xx/dma.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-s3c64xx/dma.c b/arch/arm/mach-s3c64xx/dma.c
index 8c9946f..193b07f 100644
--- a/arch/arm/mach-s3c64xx/dma.c
+++ b/arch/arm/mach-s3c64xx/dma.c
@@ -560,7 +560,8 @@ int s3c2410_dma_free(unsigned int channel, struct s3c2410_dma_client *client)
 		       channel, chan->client, client);
 	}
 
-	/* sort out stopping and freeing the channel */
+	s3c64xx_dma_flush(chan);
+	s3c64xx_dma_stop(chan);
 
 	chan->client = NULL;
 	chan->in_use = 0;
-- 
1.7.1