Re: [PATCH v1] ARM:sa1100: Remove a redundant spin lock

From: Yang,Wei
Date: Wed Jul 02 2014 - 07:02:54 EST


On 07/02/2014 06:19 PM, Russell King - ARM Linux wrote:
On Wed, Jul 02, 2014 at 05:19:40PM +0800, Yang,Wei wrote:
Hi Guys,

What about this patch?
The only concern on the face of it is that it removes mutual exclusion
from the pci config write path, where a read-modifiy-write operation is
performed.

However, the PCI code already gives that guarantee (drivers/pci/access.c)
so this should be safe.

As this is fairly old code, it would be useful to know what the motivation
is behind this change. Is it purely clean up, or is it something that
you've tested, or is this a change that you require for something else?

Thanks.

Hmm, I fixed a bug of pci config read/write of an ARM board, but unfortunately, so far ML does not support it. So
I cannot send the fix, but I grepped the pci source code of ARM architecure, I found that the pci code of a few boards always
define a static spin lock to excluse the pci config read/write path. I just intended to clean up them. If you agree the change,
I want to send v2 to also remove this mutual exclusion for something else board which also used the mutual exclusion.

Thanks
Wei
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