On Fri, 24 Aug 2012, Shilimkar, Santosh wrote:

On Fri, Aug 24, 2012 at 2:30 AM, Peter Meerwald [off-list ref] wrote:

quoted

On Wed, 18 Jul 2012, Javier Martinez Canillas wrote:

quoted

On Wed, Jul 18, 2012 at 10:36 AM, Shilimkar, Santosh
[off-list ref] wrote:

quoted

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

quoted

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
--

Hi Santosh,

And what about enabling it at the SoC config level but making the
drivers dependant on CONFIG_DMADEVICES and CONFIG_DMA_OMAP? If you
agree I can send something like this in two different patches (one for
the omap2plus_defconfig and another to make the drivers dependant on
the config option):

diff --git a/arch/arm/configs/omap2plus_defconfig

b/arch/arm/configs/omap2plus_defconfig
index b152de7..e58edc3 100644

--- a/arch/arm/configs/omap2plus_defconfig
+++ b/arch/arm/configs/omap2plus_defconfig

@@ -193,6 +193,8 @@ CONFIG_MMC_OMAP_HS=y
 CONFIG_RTC_CLASS=y
 CONFIG_RTC_DRV_TWL92330=y
 CONFIG_RTC_DRV_TWL4030=y
+CONFIG_DMADEVICES=y
+CONFIG_DMA_OMAP=y
 CONFIG_EXT2_FS=y
 CONFIG_EXT3_FS=y
 # CONFIG_EXT3_FS_XATTR is not set

above has been merged, 89269ef1f0abc72c551198123e19cd4edfd43cf4
but I am missing the patches below in mainline (3.6-rc3) -- what happened?

as Javier pointed out in https://patchwork.kernel.org/patch/1203391/,
MMC is broken support e.g. on beagleboard unless DMA_OMAP is defined

I suggest to take below patches and help to avoid some extra gray hair for
people looking for a fix for non-booting beagleboards

May be I am missing something, but why you would need below patch
for beagle with "89269ef1f0abc72c551198123e19cd4edfd43cf4" commit
enabling the DMA_OMAP for all OMAP boards.

the commit just sets CONFIG_DMA_OMAP=y and CONFIG_DMADEVICES=y in 
omap2plus_defconfig; this does not help people updating the kernel while 
keeping the config, nor does it help people in configuring the kernel

there is a dependency (at least for beagleboard) between MMC_OMAP_HS and 
DMA_OMAP, and I think this should be made explicit

regards, p.

-- 

Peter Meerwald
+43-664-2444418 (mobile)