Re: [PATCH] m32r: add simple dma
From: Sudip Mukherjee
Date: Sun Oct 30 2016 - 14:17:41 EST
Hi Andrew,
On Friday 21 October 2016 08:59 AM, Andrew Morton wrote:
On Sat, 8 Oct 2016 23:23:18 +0530 Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx> wrote:
Some builds of m32r were failing as it tried to build few drivers which
needed dma but m32r is not having dma support. Objections were raised
when it was tried to make those drivers depend on HAS_DMA.
Huh. What were these objections? That sounds like the appropriate
fix. And I suggest that a summary of those objections be captured in
this patch's changelog.
Sorry for the delay in reply. Got busy in dayjob and relocation.
I was asked to provide dma stubs instead of adding HAS_DMA in the Kconfig.
http://www.spinics.net/lists/kernel/msg2277152.html
And an old thread-
http://www.spinics.net/lists/alsa-devel/msg50931.html
It appeared to me that instead of adding dma stubs and returning error
values from them it will be better to add dma_noop to m32r. Looking at
the simplicity of dma_noop it seems that it should work.
What will you suggest? Do i send v2 after adding the "dma stub" comment
and the link to the thread in the commit message or should I opt for dma
stub?
So the next
best thing is to add dma support to m32r.
dma_noop is a very simple dma with 1:1 memory mapping.
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
---
Hi Andrew,
Just to let you know that this was not tested on any board. I think I
have told you earlier that inspite of all my efforts I could not find
any source of information to procure a board of m32r.
It is a worry. We're saying "m32r linux now supports these drivers",
only we don't know if that is true.
FYI, I tried to contact Renesas for m32r boards and this is the reply I
received (Dated- Jan 20, 2016):
"
Hi Sudip-san,
I’m afraid but I don’t know about m32r.
Also I searched our private web site, I could not find usuful
information about m32r…
Best regards,
Yoshihiro Shimoda
"
Regards
Sudip