Re: Do cpu-endian MMIO accessors exist?

[Arnd Bergmann]

On Wednesday 22 July 2009, Jiri Slaby wrote:
> No, I should have written this explicitly. I meant read* have a barrier,
> whereas ioread* do not. Similarly for writes. Is this expected?
> 
> For example:
> #define __raw_readl(a) (__chk_io_ptr(a), *(volatile u32 __force *)(a))
> #define readl(a)       ({ u32 r_ = __raw_readl(a); mb(); r_; })
> #define ioread32(a)    __raw_readl(a)

No, this looks like a bug. I would have expected

#define ioread32(a)    readl(a)

in this case. Also, ioread32 should actually multiplex between
readl() and inl() based on the address token, as the code in
lib/iomap.c does. It's probably easy enough to enable
CONFIG_GENERIC_IOMAP on sh, and remove the ioread*/iowrite*
macros from arch/sh/include/asm/io.h.

	Arnd <><
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/