On Wed, Jul 18, 2012 at 1:14 PM, S, Venkatraman [off-list ref] wrote:

On Wed, Jul 18, 2012 at 12:40 PM, Tony Lindgren [off-list ref] wrote:

quoted

* Shilimkar, Santosh [off-list ref] [120718 00:09]:

quoted

On Wed, Jul 18, 2012 at 12:29 PM, Tony Lindgren [off-list ref] wrote:

quoted

* Javier Martinez Canillas [off-list ref] [120716 23:56]:

quoted

On Tue, Jul 17, 2012 at 8:45 AM, Shilimkar, Santosh
[off-list ref] wrote:

quoted

Hi,

On Tue, Jul 17, 2012 at 6:00 AM, Javier Martinez Canillas
[off-list ref] wrote:

quoted

The OMAP MMC and OMAP High Speed MMC hosts now use entirely the DMA
engine API instead of the previous private DMA API implementation.

So, if the kernel is built with support for any of these hosts but it
doesn't support DMA devices nor OMAP DMA support, it fails when trying
to obtain a DMA channel which leads to the following error on an OMAP3
IGEPv2 Rev.C board (and probably on most OMAP boards with MMC support):

[    2.199981] omap_hsmmc omap_hsmmc.1: unable to obtain RX DMA engine channel 48
[    2.215087] omap_hsmmc omap_hsmmc.0: unable to obtain RX DMA engine channel 62

selecting automatically CONFIG_DMADEVICES and CONFIG_DMA_OMAP solves it.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
---

Considering, we are updating drivers to select the DMA engine, can you
also include
"drivers/spi/spi-omap2-mcspi.c" which is also updated for DMA engine.

Regards
Santosh

Hi Santosh,

Ok, I'll send a v2 now which includes spi-omap2-mcspi then.

I don't think we should do this, the drivers should work with and without
dma. This just needs to be added to the omap2plus_defconfig.

Well this was not decided based on any DMA CONFIG option before for
the subject drivers. It is already by default enabled if the DMA is supported
by the driver IP. There is a possibility to disable it from driver platform/dt
data so that still remains.

I think it should rather be that if the driver is broken and does not work
without DMA, it should have depends on CONFIG_DMA_OMAP.

I can confirm that omap MMC can't work without DMA; polled mode is not
supported / implemented.

Same case for SPI driver as well. It uses DMA for everything except the cases
where DMA doesn't make sense like 1 byte/2 byte etc. And its not configurable,

At least considering this, it is better we do this per driver than enabling
it at SOC config.

Regards
Santosh