[PATCH v3 1/3] ARM: Introduce atomic MMIO modify

Ezequiel Garcia ezequiel.garcia at free-electrons.com
Fri Aug 23 07:07:50 EDT 2013

On Fri, Aug 23, 2013 at 01:38:02PM +0300, Baruch Siach wrote:
> HI Ezequiel,
> On Fri, Aug 23, 2013 at 07:24:03AM -0300, Ezequiel Garcia wrote:
> > Some SoC have MMIO regions that are shared across orthogonal
> > subsystems. This commit implements a possible solution for the
> > thread-safe access of such regions through a spinlock-protected API.
> > 
> > Concurrent access is protected with a single spinlock for the
> > entire MMIO address space. While this protects shared-registers,
> > it also serializes access to unrelated/unshared registers.
> > 
> > We add relaxed and non-relaxed variants, by using writel_relaxed and writel,
> > respectively. The rationale for this is that some users may not require
> > register write completion but only thread-safe access to a register.
> > 
> > Signed-off-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
> Is there a reason why this should be limited to ARM? I haven't found anything 
> ARM specific in the code.

I guess not.

Any suggestions on where this could be located?
I can't find a suitable file in kernel/, maybe in a new file kernel/io.c?

Does this make any sense?
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering

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