Re: [PATCH V5 09/18] MIPS: Loongson: Add swiotlb to support big memory (>4GB).

[John Crispin <john@phrozen.org>]

> diff --git a/arch/mips/include/asm/mach-loongson/dma-coherence.h 
> b/arch/mips/include/asm/mach-loongson/dma-coherence.h
> index e143305..b1dc286 100644
> --- a/arch/mips/include/asm/mach-loongson/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-loongson/dma-coherence.h

[...]
>  static inline unsigned long plat_dma_addr_to_phys(struct device *dev,
>       dma_addr_t dma_addr)
>  {
> -#if defined(CONFIG_CPU_LOONGSON2F) && defined(CONFIG_64BIT)
> +#if defined(CONFIG_64BIT)
> +#if defined(CONFIG_CPU_LOONGSON3)
> +     return (dma_addr < 0x90000000 && dma_addr >= 0x80000000) ?
> +                     (dma_addr & 0x0fffffff) : dma_addr;
> +#elif defined(CONFIG_CPU_LOONGSON2F)
>       return (dma_addr > 0x8fffffff) ? dma_addr : (dma_addr & 0x0fffffff);
> +#endif /* CONFIG_CPU_LOONGSON3 */
>  #else
>       return dma_addr & 0x7fffffff;
> -#endif
> +#endif /* CONFIG_64BIT */
>  }

This will break if 64bit is defined and neither LOONGSON2F/3 are not
defined.