On Wed, 7 Nov 2007, Giuseppe Sacco wrote:
> I have been investigating about it for one week and I am still not
> convinced that mapbase must be initialised. I tried to understand the
> meaning of mapbase and membase, but I am unsure about the value I should
> set mapbase to.
>
> I learnt that when specifying mapbase its region would be registered and
> reserved using request_mem_region(). Otherwise, if you do not specify
> mapbase, the region is not reserved. Apart from reserving the memory
> region, mapbase isn't use anymore. Is mapbase mandatory?
>
> If mapbase isn't mandatory, the second part of my patch is probably
> right and fixes a bug.
You ought to use mapbase and ioremap() with new code as you are not
allowed to use readb()/writeb()/etc. on addresses obtained otherwise than
by calling ioremap(). The use of request_mem_region(), etc. is not
strictly mandatory, but it is nice to have. Many serial drivers use these
functions, so I cannot see a reason why it would be a hassle for ip32.
Maciej
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