[PATCH 1/1] mmc: host: enable OMAP DMA engine support for omap hosts by default

[S, Venkatraman]

On Fri, Jul 20, 2012 at 2:58 PM, S, Venkatraman <svenkatr at ti.com> wrote:
> On Thu, Jul 19, 2012 at 5:02 PM, Tony Lindgren <tony at atomide.com> wrote:
>> * Shilimkar, Santosh <santosh.shilimkar at ti.com> [120718 02:49]:
>>>
>>> "The patch simply make them depend on DMA_OMAP since DMA_OMAP
>>> will select DMA_ENGINE automatically"
>>>
>>> This won't be true if the DMA selection are not done
>>> at ARCH_OMAP level as discussed in this thread.
>>>
>>> Having said that, I think Russell and Tony need to
>>> take call on how this needs to be handled.
>>
>> As the DMA channels can run out, drivers should also work
>> without DMA. And building everything as modules should be
>> possible for the distro kernels.
>>
>> So I'd rather not have either select or depends and have
>> the drivers fixed.
>>
>
> Ok - I'll work on getting polling mode to work, but as you know it's
> not the mode to get the best performance out of the device.
> I see that you've also merged the changes to omap2plus_defconfig, which should
> get MMC working as before DMA Engine conversion.
>
> There's a small patch needed to omap_hsmmc to return a non-zero error code
> during the probe error path. This will atleast make probe failure
> explicit when DMA
> is not available.
>
> Let me know if you want me to post it separately as a patch..
>
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index 2338703..892a046 100644
> --- a/drivers/mmc/host/omap_hsmmc.c
> +++ b/drivers/mmc/host/omap_hsmmc.c
> @@ -1773,7 +1773,7 @@ static int __devinit omap_hsmmc_probe(struct
> platform_device *pdev)
>         struct mmc_host *mmc;
>         struct omap_hsmmc_host *host = NULL;
>         struct resource *res;
> -       int ret, irq;
> +       int ret = -ENXIO, irq;
>         const struct of_device_id *match;
>         dma_cap_mask_t mask;
>         unsigned tx_req, rx_req;

Please ignore this patch. The correct one was posted by Kevin last week [1].
An additional patch is needed on top of that to fix other error paths, I'll
send both now.

[1] http://marc.info/?l=linux-omap&m=134196391719430&w=2