Re: [PATCH v1 1/1] iommu/vt-d: use lo_hi_readq() / lo_hi_writeq()

[Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

On Mon, 2015-08-17 at 17:04 +0300, Andy Shevchenko wrote:
> There is already helper functions to do 64-bit I/O on 32-bit machines 
> or buses,
> thus we don't need to reinvent the wheel.
> 

Any comment on this one?


> Signed-off-by: Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> ---
>  include/linux/intel-iommu.h | 19 +++++--------------
>  1 file changed, 5 insertions(+), 14 deletions(-)
> 
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel
> -iommu.h
> index a868a0f..5439ea4 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -26,6 +26,8 @@
>  #include <linux/iova.h>
>  #include <linux/io.h>
>  #include <linux/dma_remapping.h>
> +
> +#include <asm-generic/io-64-nonatomic-lo-hi.h>
>  #include <asm/cacheflush.h>
>  #include <asm/iommu.h>
>  
> @@ -59,26 +61,15 @@
>  #define DMAR_IRTA_REG	0xb8    /* Interrupt remapping table addr 
> register */
>  
>  #define OFFSET_STRIDE		(9)
> -/*
> -#define dmar_readl(dmar, reg) readl(dmar + reg)
> -#define dmar_readq(dmar, reg) ({ \
> -		u32 lo, hi; \
> -		lo = readl(dmar + reg); \
> -		hi = readl(dmar + reg + 4); \
> -		(((u64) hi) << 32) + lo; })
> -*/
> +
>  static inline u64 dmar_readq(void __iomem *addr)
>  {
> -	u32 lo, hi;
> -	lo = readl(addr);
> -	hi = readl(addr + 4);
> -	return (((u64) hi) << 32) + lo;
> +	return lo_hi_readq(addr);
>  }
>  
>  static inline void dmar_writeq(void __iomem *addr, u64 val)
>  {
> -	writel((u32)val, addr);
> -	writel((u32)(val >> 32), addr + 4);
> +	lo_hi_writeq(val, addr);
>  }
>  
>  #define DMAR_VER_MAJOR(v)		(((v) & 0xf0) >> 4)

-- 
Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Intel Finland Oy