On Fri, Jan 07, 2011 at 10:26:25AM +0800, stanley.miao wrote:

Viresh Kumar wrote:

quoted

readl also calls outer cache maintainance operations 

I use readl here on spear13xx. It works fine.
This is the definition of readl, could you tell me which code calls  
outer cache maintainance ?

#define readl(c) ({ __u32 __v = le32_to_cpu((__force __le32) \
                                       __raw_readl(__mem_pci(c))); __v; })

#define readl(c)                ({ u32 __v = readl_relaxed(c); __iormb(); __v; })

is how it's now defined, and __iormb() is defined to be rmb() on ARMv7+,
which translates to a dmb.

writel() on the other hand is less straight forward.  It uses __iowmb()
which translates to a wmb() on ARMv7+, which is a dsb and an outer cache
sync operation.  This will fail in the decompressor code as there's no
outer cache support there.