* [PATCH] mmc: spi: disable dma mapping code, as it does not work
@ 2017-05-22 9:09 Phil Elwell
2017-05-23 7:58 ` Ulf Hansson
0 siblings, 1 reply; 4+ messages in thread
From: Phil Elwell @ 2017-05-22 9:09 UTC (permalink / raw)
To: Ulf Hansson, Martin Sperl, Heiner Kallweit, linux-mmc, linux-kernel
since:
commit 0589342c27944e50ebd7a54f5215002b6598b748
Author: Rob Herring <rob.herring@calxeda.com>
Date: Tue Oct 29 23:36:46 2013 -0500
of: set dma_mask to point to coherent_dma_mask
Platform devices created by DT code don't initialize dma_mask pointer to
anything. Set it to coherent_dma_mask by default if the architecture
code has not set it.
the mmc-spi driver no longer detects the sd-cards any longer.
This patch disables the offending section in mmc_spi
so that the driver works again and detects the sd card normally.
There is no real negative impact as the spi-framework
does no longer rely on driver-provided DMA mappings but
maps the transfers transparently.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Submitted-by: Phil Elwell <phil@raspberrypi.org>
---
drivers/mmc/host/mmc_spi.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index ae19d83bb9de0..16946e2513afa 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -1387,6 +1387,16 @@ static int mmc_spi_probe(struct spi_device *spi)
if (!host->data)
goto fail_nobuf1;
+ /* for some reason mmc_spi does not work with this enabled
+ * it is not needed anyway, as the SPI framework does DMA
+ * transfers now automatically
+ * the patch that introduced this was:
+ * commit 0589342c27944e50ebd7a54f5215002b6598b748
+ * Author: Rob Herring <rob.herring@calxeda.com>
+ * Date: Tue Oct 29 23:36:46 2013 -0500
+ * of: set dma_mask to point to coherent_dma_mask
+ */
+#if 0
if (spi->master->dev.parent->dma_mask) {
struct device *dev = spi->master->dev.parent;
@@ -1402,6 +1412,7 @@ static int mmc_spi_probe(struct spi_device *spi)
host->data_dma, sizeof(*host->data),
DMA_BIDIRECTIONAL);
}
+#endif
/* setup message for status/busy readback */
spi_message_init(&host->readback);
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] mmc: spi: disable dma mapping code, as it does not work
2017-05-22 9:09 [PATCH] mmc: spi: disable dma mapping code, as it does not work Phil Elwell
@ 2017-05-23 7:58 ` Ulf Hansson
2017-05-23 10:11 ` Phil Elwell
0 siblings, 1 reply; 4+ messages in thread
From: Ulf Hansson @ 2017-05-23 7:58 UTC (permalink / raw)
To: Phil Elwell; +Cc: Martin Sperl, Heiner Kallweit, linux-mmc, linux-kernel
On 22 May 2017 at 11:09, Phil Elwell <phil@raspberrypi.org> wrote:
> since:
> commit 0589342c27944e50ebd7a54f5215002b6598b748
> Author: Rob Herring <rob.herring@calxeda.com>
> Date: Tue Oct 29 23:36:46 2013 -0500
>
> of: set dma_mask to point to coherent_dma_mask
>
> Platform devices created by DT code don't initialize dma_mask pointer to
> anything. Set it to coherent_dma_mask by default if the architecture
> code has not set it.
>
> the mmc-spi driver no longer detects the sd-cards any longer.
>
> This patch disables the offending section in mmc_spi
> so that the driver works again and detects the sd card normally.
>
> There is no real negative impact as the spi-framework
> does no longer rely on driver-provided DMA mappings but
> maps the transfers transparently.
>
> Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
> Submitted-by: Phil Elwell <phil@raspberrypi.org>
> ---
> drivers/mmc/host/mmc_spi.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
> index ae19d83bb9de0..16946e2513afa 100644
> --- a/drivers/mmc/host/mmc_spi.c
> +++ b/drivers/mmc/host/mmc_spi.c
> @@ -1387,6 +1387,16 @@ static int mmc_spi_probe(struct spi_device *spi)
> if (!host->data)
> goto fail_nobuf1;
>
> + /* for some reason mmc_spi does not work with this enabled
> + * it is not needed anyway, as the SPI framework does DMA
> + * transfers now automatically
> + * the patch that introduced this was:
> + * commit 0589342c27944e50ebd7a54f5215002b6598b748
> + * Author: Rob Herring <rob.herring@calxeda.com>
> + * Date: Tue Oct 29 23:36:46 2013 -0500
> + * of: set dma_mask to point to coherent_dma_mask
> + */
> +#if 0
> if (spi->master->dev.parent->dma_mask) {
> struct device *dev = spi->master->dev.parent;
>
> @@ -1402,6 +1412,7 @@ static int mmc_spi_probe(struct spi_device *spi)
> host->data_dma, sizeof(*host->data),
> DMA_BIDIRECTIONAL);
> }
> +#endif
>
> /* setup message for status/busy readback */
> spi_message_init(&host->readback);
Phil, I am not sure how to go with this.
Your change drops the dma implementation in the mmc_spi driver as
host->dma_dev now never gets assigned. I do think that makes sense as
the dma support should be implemented in the spi master driver and not
in the spi client driver, which currently is the case for mmc_spi.
Then perhaps a more proper change would be to remove the dma
implementation in mmc_spi altogether?
And one more thing, next time also cc the spi-list and Mark Brown, to
try to some broader input.
Kind regards
Uffe
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mmc: spi: disable dma mapping code, as it does not work
2017-05-23 7:58 ` Ulf Hansson
@ 2017-05-23 10:11 ` Phil Elwell
2017-05-23 10:23 ` Ulf Hansson
0 siblings, 1 reply; 4+ messages in thread
From: Phil Elwell @ 2017-05-23 10:11 UTC (permalink / raw)
To: Ulf Hansson; +Cc: Martin Sperl, Heiner Kallweit, linux-mmc, linux-kernel
On 23/05/2017 08:58, Ulf Hansson wrote:
> On 22 May 2017 at 11:09, Phil Elwell <phil@raspberrypi.org> wrote:
>> since:
>> commit 0589342c27944e50ebd7a54f5215002b6598b748
>> Author: Rob Herring <rob.herring@calxeda.com>
>> Date: Tue Oct 29 23:36:46 2013 -0500
>>
>> of: set dma_mask to point to coherent_dma_mask
>>
>> Platform devices created by DT code don't initialize dma_mask pointer to
>> anything. Set it to coherent_dma_mask by default if the architecture
>> code has not set it.
>>
>> the mmc-spi driver no longer detects the sd-cards any longer.
>>
>> This patch disables the offending section in mmc_spi
>> so that the driver works again and detects the sd card normally.
>>
>> There is no real negative impact as the spi-framework
>> does no longer rely on driver-provided DMA mappings but
>> maps the transfers transparently.
>>
>> Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
>> Submitted-by: Phil Elwell <phil@raspberrypi.org>
>> ---
>> drivers/mmc/host/mmc_spi.c | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
>> index ae19d83bb9de0..16946e2513afa 100644
>> --- a/drivers/mmc/host/mmc_spi.c
>> +++ b/drivers/mmc/host/mmc_spi.c
>> @@ -1387,6 +1387,16 @@ static int mmc_spi_probe(struct spi_device *spi)
>> if (!host->data)
>> goto fail_nobuf1;
>>
>> + /* for some reason mmc_spi does not work with this enabled
>> + * it is not needed anyway, as the SPI framework does DMA
>> + * transfers now automatically
>> + * the patch that introduced this was:
>> + * commit 0589342c27944e50ebd7a54f5215002b6598b748
>> + * Author: Rob Herring <rob.herring@calxeda.com>
>> + * Date: Tue Oct 29 23:36:46 2013 -0500
>> + * of: set dma_mask to point to coherent_dma_mask
>> + */
>> +#if 0
>> if (spi->master->dev.parent->dma_mask) {
>> struct device *dev = spi->master->dev.parent;
>>
>> @@ -1402,6 +1412,7 @@ static int mmc_spi_probe(struct spi_device *spi)
>> host->data_dma, sizeof(*host->data),
>> DMA_BIDIRECTIONAL);
>> }
>> +#endif
>>
>> /* setup message for status/busy readback */
>> spi_message_init(&host->readback);
>
> Phil, I am not sure how to go with this.
>
> Your change drops the dma implementation in the mmc_spi driver as
> host->dma_dev now never gets assigned. I do think that makes sense as
> the dma support should be implemented in the spi master driver and not
> in the spi client driver, which currently is the case for mmc_spi.
>
> Then perhaps a more proper change would be to remove the dma
> implementation in mmc_spi altogether?
I don't have enough in-depth SPI knowledge to make that decision - I'm happy to go
with what the SPI experts recommend.
> And one more thing, next time also cc the spi-list and Mark Brown, to
> try to some broader input.
Thanks for the tip, Ulf - I just went with what scripts/get_maintainer.pl suggested.
Perhaps that list needs to be updated?
Phil
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mmc: spi: disable dma mapping code, as it does not work
2017-05-23 10:11 ` Phil Elwell
@ 2017-05-23 10:23 ` Ulf Hansson
0 siblings, 0 replies; 4+ messages in thread
From: Ulf Hansson @ 2017-05-23 10:23 UTC (permalink / raw)
To: Phil Elwell; +Cc: Martin Sperl, Heiner Kallweit, linux-mmc, linux-kernel
On 23 May 2017 at 12:11, Phil Elwell <phil@raspberrypi.org> wrote:
> On 23/05/2017 08:58, Ulf Hansson wrote:
>> On 22 May 2017 at 11:09, Phil Elwell <phil@raspberrypi.org> wrote:
>>> since:
>>> commit 0589342c27944e50ebd7a54f5215002b6598b748
>>> Author: Rob Herring <rob.herring@calxeda.com>
>>> Date: Tue Oct 29 23:36:46 2013 -0500
>>>
>>> of: set dma_mask to point to coherent_dma_mask
>>>
>>> Platform devices created by DT code don't initialize dma_mask pointer to
>>> anything. Set it to coherent_dma_mask by default if the architecture
>>> code has not set it.
>>>
>>> the mmc-spi driver no longer detects the sd-cards any longer.
>>>
>>> This patch disables the offending section in mmc_spi
>>> so that the driver works again and detects the sd card normally.
>>>
>>> There is no real negative impact as the spi-framework
>>> does no longer rely on driver-provided DMA mappings but
>>> maps the transfers transparently.
>>>
>>> Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
>>> Submitted-by: Phil Elwell <phil@raspberrypi.org>
>>> ---
>>> drivers/mmc/host/mmc_spi.c | 11 +++++++++++
>>> 1 file changed, 11 insertions(+)
>>>
>>> diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
>>> index ae19d83bb9de0..16946e2513afa 100644
>>> --- a/drivers/mmc/host/mmc_spi.c
>>> +++ b/drivers/mmc/host/mmc_spi.c
>>> @@ -1387,6 +1387,16 @@ static int mmc_spi_probe(struct spi_device *spi)
>>> if (!host->data)
>>> goto fail_nobuf1;
>>>
>>> + /* for some reason mmc_spi does not work with this enabled
>>> + * it is not needed anyway, as the SPI framework does DMA
>>> + * transfers now automatically
>>> + * the patch that introduced this was:
>>> + * commit 0589342c27944e50ebd7a54f5215002b6598b748
>>> + * Author: Rob Herring <rob.herring@calxeda.com>
>>> + * Date: Tue Oct 29 23:36:46 2013 -0500
>>> + * of: set dma_mask to point to coherent_dma_mask
>>> + */
>>> +#if 0
>>> if (spi->master->dev.parent->dma_mask) {
>>> struct device *dev = spi->master->dev.parent;
>>>
>>> @@ -1402,6 +1412,7 @@ static int mmc_spi_probe(struct spi_device *spi)
>>> host->data_dma, sizeof(*host->data),
>>> DMA_BIDIRECTIONAL);
>>> }
>>> +#endif
>>>
>>> /* setup message for status/busy readback */
>>> spi_message_init(&host->readback);
>>
>> Phil, I am not sure how to go with this.
>>
>> Your change drops the dma implementation in the mmc_spi driver as
>> host->dma_dev now never gets assigned. I do think that makes sense as
>> the dma support should be implemented in the spi master driver and not
>> in the spi client driver, which currently is the case for mmc_spi.
>>
>> Then perhaps a more proper change would be to remove the dma
>> implementation in mmc_spi altogether?
>
> I don't have enough in-depth SPI knowledge to make that decision - I'm happy to go
> with what the SPI experts recommend.
Okay. Let's see.
>
>> And one more thing, next time also cc the spi-list and Mark Brown, to
>> try to some broader input.
>
> Thanks for the tip, Ulf - I just went with what scripts/get_maintainer.pl suggested.
> Perhaps that list needs to be updated?
No, this is more a special case I would say.
Kind regards
Uffe
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-05-22 9:09 [PATCH] mmc: spi: disable dma mapping code, as it does not work Phil Elwell
2017-05-23 7:58 ` Ulf Hansson
2017-05-23 10:11 ` Phil Elwell
2017-05-23 10:23 ` Ulf Hansson
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