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[V3,2/3] dmaengine: dw_dmac: Enhance device tree support

Message ID CAKohpo=FjZuMOC-wuNc3q_FXbk546ttCLr55GkW9AL0Tz-HoBA@mail.gmail.com (mailing list archive)
State New, archived
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Commit Message

Viresh Kumar Dec. 12, 2012, 3 a.m. UTC 
Sorry for replying late, was too busy with other work yesterday.

On 11 December 2012 03:38, Arnd Bergmann <arnd@arndb.de> wrote:
> I'm deeply sorry for the very late complaint on this, but I only now

Better late than never :)

> noticed this patch as I was seeing build breakage in linux-next
> because of it.

Oops!! Here is a fix for that

Author: Viresh Kumar <viresh.kumar@linaro.org>
Date:   Wed Dec 12 08:28:07 2012 +0530

    ARM: SPEAr1310: Fix CF DMA data

    We need to pass string with device-channel name to dma controller
instead of dma
    controller specific dma struct. Fix CF dma data.

    Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 arch/arm/mach-spear13xx/spear1310.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

>
> * It does not follow the binding from
>   Documentation/devicetree/bindings/dma/dma.txt

When i patched it, this patch wasn't there in linux-next/master.
Probably was getting reviewed somewhere :)

> * It requires slave drivers to know that they are using the dw_dmac
>   driver and pass a pointer to dw_generic_filter, which is not
>   generic at all
>
> * It requires the dmac node to have information about all slaves
>
> There are also some minor issues, such as the naming of DT
> properties, but the above need to be resolved first.

I saw the binding document and it looks it can be applied to dw_dmac
too, as there is nothing special for it.

The question is how? We are already late for merge window and this
one is queued. Supplying a new patch, getting it reviewed/tested and
being pulled by Linus is not so easy :)

Two ways:
- Keep it as is, and i will fix it separately and quickly
- Drop it :(

--
viresh

Comments

Andy Shevchenko Dec. 12, 2012, 8:40 a.m. UTC | #1 
On Wed, 2012-12-12 at 08:30 +0530, Viresh Kumar wrote: 
> > * It requires slave drivers to know that they are using the dw_dmac
> >   driver and pass a pointer to dw_generic_filter, which is not
> >   generic at all
> >
> > * It requires the dmac node to have information about all slaves
> >
> > There are also some minor issues, such as the naming of DT
> > properties, but the above need to be resolved first.
> 
> I saw the binding document and it looks it can be applied to dw_dmac
> too, as there is nothing special for it.
> 
> The question is how? We are already late for merge window and this
> one is queued. Supplying a new patch, getting it reviewed/tested and
> being pulled by Linus is not so easy :)
> 
> Two ways:
> - Keep it as is, and i will fix it separately and quickly
> - Drop it :(
Will we survive if the patch is in mainline? I mean how big the impact
of it is?
Viresh Kumar Dec. 12, 2012, 8:43 a.m. UTC | #2 
On 12 December 2012 14:10, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> Will we survive if the patch is in mainline? I mean how big the impact
> of it is?

It doesn't fail to do fulfill its purpose and even ALL DT stuff would work well.
Its just the matter of using the right API's, design and bindings :)
Arnd Bergmann Jan. 8, 2013, 11:09 p.m. UTC | #3 
On Wednesday 12 December 2012, Viresh Kumar wrote:
> I saw the binding document and it looks it can be applied to dw_dmac
> too, as there is nothing special for it.
> 
> The question is how? We are already late for merge window and this
> one is queued. Supplying a new patch, getting it reviewed/tested and
> being pulled by Linus is not so easy :)
> 
> Two ways:
> - Keep it as is, and i will fix it separately and quickly
> - Drop it :(

It seems we got both lucky and unlucky here, as all the dmaengine patches,
including this set and the generic DT bindings missed out in the end.
So there is time to fix it all for 3.9.

	Arnd
diff mbox

Patch

diff --git a/arch/arm/mach-spear13xx/spear1310.c
b/arch/arm/mach-spear13xx/spear1310.c
index f65ad5b..54f0e2e 100644
--- a/arch/arm/mach-spear13xx/spear1310.c
+++ b/arch/arm/mach-spear13xx/spear1310.c
@@ -36,7 +36,7 @@ 
 static struct arasan_cf_pdata cf_pdata = {
        .cf_if_clk = CF_IF_CLK_166M,
        .quirk = CF_BROKEN_UDMA,
-       .dma_priv = &cf_dma_priv,
+       .dma_priv = "cf",
 };

> Viresh, there are multiple problems with your approach unfortunately: