Re: [PATCH 1/5] device: introduce resource structure to simplify resource delaration

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 14:58 Sat 20 Nov     , Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 14:40 Sat 20 Nov     , Sascha Hauer wrote:
> > On Fri, Nov 19, 2010 at 12:30:09PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > On 09:00 Fri 19 Nov     , Sascha Hauer wrote:
> > > > Hi J,
> > > > 
> > > > On Fri, Nov 12, 2010 at 07:18:54PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > > > introdude also some helper to manager them
> > > > > 
> > > > > and add multi resource per device support
> > > > > 
> > > > > ram device: use resource structure instead of memory_platform_data
> > > > > 
> > > > > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
> > > > 
> > > > 
> > > > You shouldn't use a resource_size_t type to access registers. This will
> > > > lead to problems when we start to support 64bit resource sizes
> > > no as resource_size_t is 64 bit aware
> > 
> > And exactly this is the problem. void * is usually only 32bit on arm.
> > This will lead to compiler warnings and sparse isn't happy about
> > unsigned long in readl/writel anyway.
> IIRC on arm resource_size_t is never 64bit at least on the current ARMvx
> 
> > 
> > > >. Instead we should introduce a
> > > > 
> > > > #define resource_size_to_iomem(size) (void __force __iomem *)(size)
> > > > 
> > > > macro which does the conversion to a void __iomem * type. In a more
> > > > advanced version this could also spit a warning when the resource start
> > > > is bigger than a pointer type. As an additional plus we'll get rid of
> > > > some sparse warnings where map_base is used for readl/writel.
> > > we do not do in the kernel and do see the advantage here for the ressource
> > > in mind it's in the drivers we need to do it
> > > if necessary
> > 
> > resource_size_t is never passed to readl/writel in the kernel.
> yeah but the resources are cast in the drivers
I check on x86 and void is 4 byte on 32bit and 8bytes on 64bit

Best Regards,
J.

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