About the workaround for the 484863 L220 erratum

[Will Deacon]

On Tue, Dec 04, 2012 at 12:57:57PM +0000, Asano, Yasushi wrote:
> Hi,
> 
> I am looking for a workaround for the 484863 L220 erratum. 
> "484863: The Cache Sync operation does not guarantee that the Eviction Buffer is empty"
> 
> Then I found a patch as below.
> http://www.linux-arm.org/git?p=linux-2.6-stable.git;a=commitdiff;h=61f0ab1658f41f34c1910848063c565095a47864
> Though It seems to need should correct this probrem, this patch has not been marged into the mainline yet.
> 
> v3.6.9　arch/arm/include/asm/io.h
> #define writel_relaxed(v,c)     __raw_writel((__force u32) cpu_to_le32(v),c)

What's the significance of this?

> Could you please tell me if you know the reason why it does not get into the mainline.

Probably because, looking at the patch in question, it uses a swp
instruction in the kernel which could be fatal if we have swp emulation
enabled (we only emulate for user mode).

Will