From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Sat, 12 Jul 2014 15:18:11 +0100 Subject: [PATCH v2 2/3] ARM: Use include/asm-generic/io.h In-Reply-To: <201407121427.22668.arnd@arndb.de> References: <1405092672-18549-1-git-send-email-thierry.reding@gmail.com> <1405092672-18549-2-git-send-email-thierry.reding@gmail.com> <20140711162422.GF16321@arm.com> <201407121427.22668.arnd@arndb.de> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 12 Jul 2014, at 13:27, Arnd Bergmann wrote: > On Friday 11 July 2014, Catalin Marinas wrote: >> >> On Fri, Jul 11, 2014 at 04:31:11PM +0100, Thierry Reding wrote: >>> diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h >>> index a78562f21aab..ef54f5c8a7ae 100644 >>> --- a/arch/arm/include/asm/io.h >>> +++ b/arch/arm/include/asm/io.h >> [...] >>> -#define iowrite16be(v,p) ({ __iowmb(); __raw_writew((__force __u16)cpu_to_be16(v), p); }) >>> -#define iowrite32be(v,p) ({ __iowmb(); __raw_writel((__force __u32)cpu_to_be32(v), p); }) >> >> Aren't you losing the barrier semantics here? The generic iowrite*be() >> functions call __raw_write*() directly which don't have a barrier >> (write* accessors do). > > Indeed, sorry for missing this. The generic implementation still makes sense for > include/asm-generic, but arm32 and arm64 must provide their own versions here. I think this would be the easiest. But the asm-generic/io.h needs some #ifndef iowrite16be checks. (in arm64 we missed the iowrite*be barriers completely, so not broken by this patch; Thierry could update arm64 as well with patch 3/3) Catalin