Re: [Xen-devel] [PATCH v4 01/21] arm/acpi: Emulate io ports for arm

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 28 Jan 2016, Shannon Zhao wrote:
> On 2016/1/27 20:52, Stefano Stabellini wrote:
> > On Sat, 23 Jan 2016, Shannon Zhao wrote:
> >> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> >>
> >> Add macros to emulate x86 style ports for arm. This avoids modification in
> >> common code for acpi. Here just print a warning on ARM.
> >>
> >> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> >> ---
> >> V4: print warning
> >> ---
> >>  xen/include/asm-arm/arm64/io.h | 18 ++++++++++++++++++
> >>  1 file changed, 18 insertions(+)
> >>
> >> diff --git a/xen/include/asm-arm/arm64/io.h 
> >> b/xen/include/asm-arm/arm64/io.h
> >> index 37abc47..ec5815d 100644
> >> --- a/xen/include/asm-arm/arm64/io.h
> >> +++ b/xen/include/asm-arm/arm64/io.h
> >> @@ -20,6 +20,7 @@
> >>  #ifndef _ARM_ARM64_IO_H
> >>  #define _ARM_ARM64_IO_H
> >>  
> >> +#include <asm/system.h>
> >>  #include <asm/byteorder.h>
> >>  
> >>  /*
> >> @@ -109,4 +110,21 @@ static inline u64 __raw_readq(const volatile void 
> >> __iomem *addr)
> >>  #define writel(v,c)             ({ __iowmb(); writel_relaxed((v),(c)); })
> >>  #define writeq(v,c)             ({ __iowmb(); writeq_relaxed((v),(c)); })
> >>  
> >> +/*
> >> + * Emulate x86 io ports for ARM.
> >> + */
> >> +static inline void __iomem * __armio(u64 addr)
> >> +{
> >> +    printk(XENLOG_G_WARNING "Can't access IO %lx\n", addr);
> >> +    return (void __iomem *)addr;
> >> +}
> >> +
> >> +#define inb(c) ( readb( __armio(c) ) )
> >> +#define inw(c) ( readw( __armio(c) ) )
> >> +#define inl(c) ( readl( __armio(c) ) )
> >> +
> >> +#define outb(v, c) ( writeb(v, __armio(c) ) )
> >> +#define outw(v, c) ( writew(v, __armio(c) ) )
> >> +#define outl(v, c) ( writel(v, __armio(c) ) )
> > 
> > This is better than before, but it would still end up causing a write to
> > happen on outb, outw and outl. I would define them in a way so that
> > only the warning gets printed when they are called and nothing else.
> > 
> 
> How about this?

That's good


> +/*
> + * Emulate x86 io ports for ARM.
> + */
> +static inline int emulate_read(u64 addr)
> +{
> +    printk(XENLOG_G_WARNING "Can't access IO %lx\n", addr);
> +    return 0;
> +}
> +
> +static inline void emulate_write(u64 addr)
> +{
> +    printk(XENLOG_G_WARNING "Can't access IO %lx\n", addr);
> +}
> +
> +#define inb(c) ( emulate_read(c) )
> +#define inw(c) ( emulate_read(c) )
> +#define inl(c) ( emulate_read(c) )
> +
> +#define outb(v, c) ( emulate_write(c) )
> +#define outw(v, c) ( emulate_write(c) )
> +#define outl(v, c) ( emulate_write(c) )
> 
> Thanks,
> -- 
> Shannon
> 

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