Re: [PATCH] drivers/block/xsysace - replace in(out)_8/in(out)_be16/in(out)_le16with generic iowrite(read)8/16(be)

From: Michal Simek
Date: Tue Feb 12 2013 - 05:03:40 EST

2013/2/12 Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>:
> On Mon, 2013-02-11 at 16:57 +0100, Michal Simek wrote:
>> But it reminds me that maybe the easiest solution is not to use endian
>> accessors just use two simple macros which should work on all systems.
>> #define <name>_readreg(offset) ({__raw_readl(offset); rmb(); })
>> #define <name>_writereg(offset, val) ({wmb(); __raw_writel(val, offset); })
>> which is probably the faster solution which add minimum additional code
>> to driver and can also remove endian detection code.
> Except that rmb & wmb might not be the right barriers for IOs ...

Arm is using __iormb in readX macros
#define __iormb() rmb()
but it is arm specific only that's why I have added there rmb().


Michal Simek, Ing. (M.Eng)
w: p: +42-0-721842854
Maintainer of Linux kernel - Microblaze cpu -
Maintainer of Linux kernel - Xilinx Zynq ARM architecture
Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform
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