Re: [Xen-devel] [PATCH RFC 2/8] xen/arm: implement read[bl] and write[bl]

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 09/10/2013 04:09 PM, Ian Campbell wrote:
> On Tue, 2013-09-10 at 16:00 +0100, Julien Grall wrote:
>> On 09/10/2013 03:18 PM, Ian Campbell wrote:
>>> These are used in common driver code (specifically ns16550)
>>
>> Can you implement read[bl] and write[bl] also for arm64?
> 
> Uhm, yesm that's something of a prerequisite actually -- these functiosn
> are in a common location so they need to be moved!

BTW, there is already an implementation for readl/writel but called
ioreadl/iowritel.

You can either rename the functions or add some macros.

> Well spotted.
> 
> I should also have mentioned the Linux heritage of these functions in
> the commit message and/or in a code comment, which was remiss of me.
> 
>>
>>> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>>> ---
>>>  xen/include/asm-arm/io.h |   48 
>>> ++++++++++++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 48 insertions(+)
>>>
>>> diff --git a/xen/include/asm-arm/io.h b/xen/include/asm-arm/io.h
>>> index aea5233..170263f 100644
>>> --- a/xen/include/asm-arm/io.h
>>> +++ b/xen/include/asm-arm/io.h
>>> @@ -1,6 +1,54 @@
>>>  #ifndef _ASM_IO_H
>>>  #define _ASM_IO_H
>>>  
>>> +static inline void __raw_writeb(u8 val, volatile void __iomem *addr)
>>> +{
>>> +        asm volatile("strb %1, %0"
>>> +                     : "+Qo" (*(volatile u8 __force *)addr)
>>> +                     : "r" (val));
>>> +}
>>> +
>>> +static inline void __raw_writel(u32 val, volatile void __iomem *addr)
>>> +{
>>> +        asm volatile("str %1, %0"
>>> +                     : "+Qo" (*(volatile u32 __force *)addr)
>>> +                     : "r" (val));
>>> +}
>>> +
>>> +static inline u8 __raw_readb(const volatile void __iomem *addr)
>>> +{
>>> +        u8 val;
>>> +        asm volatile("ldrb %1, %0"
>>> +                     : "+Qo" (*(volatile u8 __force *)addr),
>>> +                       "=r" (val));
>>> +        return val;
>>> +}
>>> +
>>> +static inline u32 __raw_readl(const volatile void __iomem *addr)
>>> +{
>>> +        u32 val;
>>> +        asm volatile("ldr %1, %0"
>>> +                     : "+Qo" (*(volatile u32 __force *)addr),
>>> +                       "=r" (val));
>>> +        return val;
>>> +}
>>> +
>>> +#define __iormb()               rmb()
>>> +#define __iowmb()               wmb()
>>> +
>>> +#define readb_relaxed(c) ({ u8  __r = __raw_readb(c); __r; })
>>> +#define readl_relaxed(c) ({ u32 __r = le32_to_cpu((__force __le32) \
>>> +                                        __raw_readl(c)); __r; })
>>> +
>>> +#define writeb_relaxed(v,c)     __raw_writeb(v,c)
>>> +#define writel_relaxed(v,c)     __raw_writel((__force u32) 
>>> cpu_to_le32(v),c)
>>> +
>>> +#define readb(c)                ({ u8  __v = readb_relaxed(c); __iormb(); 
>>> __v; })
>>> +#define readl(c)                ({ u32 __v = readl_relaxed(c); __iormb(); 
>>> __v; })
>>> +
>>> +#define writeb(v,c)             ({ __iowmb(); writeb_relaxed(v,c); })
>>> +#define writel(v,c)             ({ __iowmb(); writel_relaxed(v,c); })
>>> +
>>>  #endif
>>>  /*
>>>   * Local variables:
>>>
>>
>>
> 
> 


-- 
Julien Grall

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