Re: [PATCH] serial: atmel: fix compiler warning on address cast

[Alexandre Belloni <alexandre.belloni@free-electrons.com>]

On 08/10/2015 at 10:37:49 +0100, Russell King - ARM Linux wrote :
> On Thu, Oct 08, 2015 at 11:01:48AM +0200, Alexandre Belloni wrote:
> > On 05/10/2015 at 18:00:52 +0100, Andre Przywara wrote :
> > > Turning on KVM and LPAE support on top of a multi_v7_defconfig will
> > > produce a compiler warning in the Atmel serial driver:
> > > drivers/tty/serial/atmel_serial.c: In function 'atmel_verify_port':
> > > drivers/tty/serial/atmel_serial.c:2299:6: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
> > >   if ((void *)port->mapbase != ser->iomem_base)
> > >       ^
> > > 
> > > Fix that by using the cast on the right hand side instead, as similar
> > > code already does in other drivers.
> > > 
> > > Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> > Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> 
> Hmm, this actually points at a problem, and the cast screems out about it.
> Think about it, can you guess what it is?
> 

My understanding of the issue is that port->mapbase is a 64bit
resource_size_t, and is larger than void * hence the warning. Casting
iomem_base to unsigned long seems safe to me, am I wrong?


-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com