Re: [PATCH] x86_64: Add memcpy32_toio to write to PCI MMIO

From: Clemens Ladisch
Date: Tue Sep 09 2014 - 04:01:32 EST


Subhransu S. Prusty wrote:
> This is needed because the hardware

Which hardware? Every x86-64 CPU ever built by AMD, Intel, and VIA?

> does not support 64-bit moveq insructions while writing to PCI MMIO.

> +#ifndef CONFIG_X86_64
> +#define MEMCPY_TOIO memcpy_toio
> +#else
> +#define MEMCPY_TOIO memcpy32_toio
> +#endif

This does not change any code that uses memcpy_toio().

> + for (i = 0; i < count/sizeof(u32); i++)
> + writel(*src_32++, dst_32++);

This breaks when count is not a multiple of four.


Regards,
Clemens
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