[PATCH] mtd: nand: pxa3xx_nand: fix dmaengine initialization

[PATCH] mtd: nand: pxa3xx_nand: fix dmaengine initialization

[Robert Jarzmik]

When the driver is initialized in a pure device-tree platform, the
driver's probe fails allocating the dma channel :
[  525.624435] pxa3xx-nand 43100000.nand: no resource defined for data DMA
[  525.632088] pxa3xx-nand 43100000.nand: alloc nand resource failed

The reason is that the DMA IO resource is not acquired through platform
resources but by OF bindings.

Fix this by ensuring that DMA IO resources are only queried in the non
device-tree case.

Fixes: 8f5ba31aa565 ("mtd: nand: pxa3xx-nand: switch to dmaengine")
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 drivers/mtd/nand/pxa3xx_nand.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
index a168cbcc1086..afd487d4b67f 100644
--- a/drivers/mtd/nand/pxa3xx_nand.c
+++ b/drivers/mtd/nand/pxa3xx_nand.c
@@ -1750,7 +1750,7 @@ static int alloc_nand_resource(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
-	if (use_dma) {
+	if (!np && use_dma) {
 		r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 		if (r == NULL) {
 			dev_err(&pdev->dev,
-- 
2.1.4

Re: [PATCH] mtd: nand: pxa3xx_nand: fix dmaengine initialization

[Ezequiel Garcia]

On 12 February 2016 at 19:29, Robert Jarzmik <robert.jarzmik@free.fr> wrote:
> When the driver is initialized in a pure device-tree platform, the
> driver's probe fails allocating the dma channel :
> [  525.624435] pxa3xx-nand 43100000.nand: no resource defined for data DMA
> [  525.632088] pxa3xx-nand 43100000.nand: alloc nand resource failed
>
> The reason is that the DMA IO resource is not acquired through platform
> resources but by OF bindings.
>
> Fix this by ensuring that DMA IO resources are only queried in the non
> device-tree case.
>
> Fixes: 8f5ba31aa565 ("mtd: nand: pxa3xx-nand: switch to dmaengine")
> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
> ---
>  drivers/mtd/nand/pxa3xx_nand.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
> index a168cbcc1086..afd487d4b67f 100644
> --- a/drivers/mtd/nand/pxa3xx_nand.c
> +++ b/drivers/mtd/nand/pxa3xx_nand.c
> @@ -1750,7 +1750,7 @@ static int alloc_nand_resource(struct platform_device *pdev)
>         if (ret < 0)
>                 return ret;
>
> -       if (use_dma) {
> +       if (!np && use_dma) {
>                 r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
>                 if (r == NULL) {
>                         dev_err(&pdev->dev,

Looking through the kernel tree, this change seems to be correct.

However, I'm still wondering how DMA resources are obtained in the
device-tree case. Can you explain it to me?
-- 
Ezequiel García, VanguardiaSur
www.vanguardiasur.com.ar

Re: [PATCH] mtd: nand: pxa3xx_nand: fix dmaengine initialization

[Robert Jarzmik]

Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> writes:

> On 12 February 2016 at 19:29, Robert Jarzmik <robert.jarzmik@free.fr> wrote:
>> When the driver is initialized in a pure device-tree platform, the
>> driver's probe fails allocating the dma channel :
>> [  525.624435] pxa3xx-nand 43100000.nand: no resource defined for data DMA
>> [  525.632088] pxa3xx-nand 43100000.nand: alloc nand resource failed
>>
>> The reason is that the DMA IO resource is not acquired through platform
>> resources but by OF bindings.
>>
>> Fix this by ensuring that DMA IO resources are only queried in the non
>> device-tree case.
>>
>> Fixes: 8f5ba31aa565 ("mtd: nand: pxa3xx-nand: switch to dmaengine")
>> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
>> ---
>>  drivers/mtd/nand/pxa3xx_nand.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
>> index a168cbcc1086..afd487d4b67f 100644
>> --- a/drivers/mtd/nand/pxa3xx_nand.c
>> +++ b/drivers/mtd/nand/pxa3xx_nand.c
>> @@ -1750,7 +1750,7 @@ static int alloc_nand_resource(struct platform_device *pdev)
>>         if (ret < 0)
>>                 return ret;
>>
>> -       if (use_dma) {
>> +       if (!np && use_dma) {
>>                 r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
>>                 if (r == NULL) {
>>                         dev_err(&pdev->dev,
>
> Looking through the kernel tree, this change seems to be correct.
>
> However, I'm still wondering how DMA resources are obtained in the
> device-tree case. Can you explain it to me?

In the pxa case, look at my extract in [1].
The lines to consider are :
			dmas = <&pdma 97 3>;
			dma-names = "data";

Now have a look at the function pxad_dma_xlate() in drivers/dma/pxa_dma.c.
You'll see that the "97" ends up in the chanel drcmr, and the "3" in the
channel's prio, when the chanel is requested in the nand driver by calling
dma_request_slave_channel_compat(). In the latter case, pxad_filter_fn() is not
used, it's the pxad_dma_xlate() which is used instead.

Is this what you were looking for ?

Cheers.

-- 
Robert

[1] Extract of my zylonite310.dts
		nand0: nand@43100000 {
			compatible = "marvell,pxa3xx-nand";
			reg = <0x43100000 90>;
			interrupts = <45>;
			clocks = <&clks CLK_NAND>;
			dmas = <&pdma 97 3>;
			dma-names = "data";
			#address-cells = <1>;
			#size-cells = <1>;	
			status = "disabled";
		};

Re: [PATCH] mtd: nand: pxa3xx_nand: fix dmaengine initialization

[Ezequiel Garcia]

On 27 February 2016 at 07:45, Robert Jarzmik <robert.jarzmik@free.fr> wrote:
> Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> writes:
>
>> On 12 February 2016 at 19:29, Robert Jarzmik <robert.jarzmik@free.fr> wrote:
>>> When the driver is initialized in a pure device-tree platform, the
>>> driver's probe fails allocating the dma channel :
>>> [  525.624435] pxa3xx-nand 43100000.nand: no resource defined for data DMA
>>> [  525.632088] pxa3xx-nand 43100000.nand: alloc nand resource failed
>>>
>>> The reason is that the DMA IO resource is not acquired through platform
>>> resources but by OF bindings.
>>>
>>> Fix this by ensuring that DMA IO resources are only queried in the non
>>> device-tree case.
>>>
>>> Fixes: 8f5ba31aa565 ("mtd: nand: pxa3xx-nand: switch to dmaengine")
>>> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
>>> ---
>>>  drivers/mtd/nand/pxa3xx_nand.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
>>> index a168cbcc1086..afd487d4b67f 100644
>>> --- a/drivers/mtd/nand/pxa3xx_nand.c
>>> +++ b/drivers/mtd/nand/pxa3xx_nand.c
>>> @@ -1750,7 +1750,7 @@ static int alloc_nand_resource(struct platform_device *pdev)
>>>         if (ret < 0)
>>>                 return ret;
>>>
>>> -       if (use_dma) {
>>> +       if (!np && use_dma) {
>>>                 r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
>>>                 if (r == NULL) {
>>>                         dev_err(&pdev->dev,
>>
>> Looking through the kernel tree, this change seems to be correct.
>>
>> However, I'm still wondering how DMA resources are obtained in the
>> device-tree case. Can you explain it to me?
>
> In the pxa case, look at my extract in [1].
> The lines to consider are :
>                         dmas = <&pdma 97 3>;
>                         dma-names = "data";
>
> Now have a look at the function pxad_dma_xlate() in drivers/dma/pxa_dma.c.
> You'll see that the "97" ends up in the chanel drcmr, and the "3" in the
> channel's prio, when the chanel is requested in the nand driver by calling
> dma_request_slave_channel_compat(). In the latter case, pxad_filter_fn() is not
> used, it's the pxad_dma_xlate() which is used instead.
>
> Is this what you were looking for ?
>

I see. That's exactly what I was missing.

Acked-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>

Thanks,
-- 
Ezequiel García, VanguardiaSur
www.vanguardiasur.com.ar

Re: [PATCH] mtd: nand: pxa3xx_nand: fix dmaengine initialization

[Brian Norris]

On Fri, Feb 12, 2016 at 11:29:04PM +0100, Robert Jarzmik wrote:
> When the driver is initialized in a pure device-tree platform, the
> driver's probe fails allocating the dma channel :
> [  525.624435] pxa3xx-nand 43100000.nand: no resource defined for data DMA
> [  525.632088] pxa3xx-nand 43100000.nand: alloc nand resource failed
> 
> The reason is that the DMA IO resource is not acquired through platform
> resources but by OF bindings.
> 
> Fix this by ensuring that DMA IO resources are only queried in the non
> device-tree case.
> 
> Fixes: 8f5ba31aa565 ("mtd: nand: pxa3xx-nand: switch to dmaengine")
> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>

Applied to l2-mtd.git