Re: [Xen-devel] [PATCH v1 2/8] xen/arm: io: Extend write/read handler to pass the register in parameter

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 25/09/15 17:36, Ian Campbell wrote:
> On Fri, 2015-09-25 at 15:51 +0100, Julien Grall wrote:
>> From: Julien Grall <julien.grall@xxxxxxxxxx>
>>
>> Rather than letting each handler to retrieve the register used by the
>> I/O access, add a new parameter to pass the register in parameter.
>>
>> This will help to implement generic register manipulation on I/O access
>> such as sign-extension and endianess.
>>
>> Read handlers need to modify the value of the register, so a pointer to
>> it is given in argument. Write handlers shouldn't modify the register,
>> therfore only a plain value is given.
> 
> "therefore"
>>
>> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> 
> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxxx
> 
> Is it the case that read handlers today only update *r on success? 

Yes, each read handler only update the register mentioned in dabt.reg.

> Is that
> a useful thing to mandate and/or enforce?

What do you mean?

Regards,

-- 
Julien Grall

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