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
