[RFC PATCH 1/2] arm: introduce arch_ioremap and arch_iounmap function pointer

[plagnioj@jcrosoft.com (Jean-Christophe PLAGNIOL-VILLARD)]

On 14:19 Sun 22 May     , Russell King - ARM Linux wrote:
> On Sun, May 22, 2011 at 01:05:43PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > did see that and I should I did it on at91 too
> > 
> > so how about introduce a new ioreamap/iouremap functiom
> 
> How about not.  How about we intercept all the ioremap() calls at a better
> place like at the beginning of __arm_ioremap_pfn_caller() - iow, something
> like this:
> 
> void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
>         unsigned long offset, size_t size, unsigned int mtype, void *caller)
> {
>         const struct mem_type *type;
>         int err;
>         unsigned long addr;
>         struct vm_struct * area;
> 
>         /*
>          * High mappings must be supersection aligned
>          */
>         if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK))
>                 return NULL;
> 
>         /*
>          * Don't allow RAM to be mapped - this causes problems with ARMv6+
>          */
>         if (WARN_ON(pfn_valid(pfn)))
>                 return NULL;
> 
>         type = get_mem_type(mtype);
>         if (!type)
>                 return NULL;
> 
>         /*
>          * Page align the mapping size, taking account of any offset.
>          */
>         size = PAGE_ALIGN(offset + size);
> 
> +	addr = __arch_ioremap(pfn, size);
> +	if (addr)
> +		return (void __iomem *) (offset + addr);
> 	...
> 
> and then we can have __arch_ioremap() do whatever checking of static
> mappings we desire.
I like that

and for ioummap

void __iounmap(volatile void __iomem *io_addr)
{
        void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
#ifndef CONFIG_SMP
        struct vm_struct **p, *tmp;
+#endif

+	__arch_iounmap(io_addr);
+
+#ifndef CONFIG_SMP
        /*
         * If this is a section based mapping we need to handle it
         * specially as the VM subsystem does not know how to handle
         * such a beast. We need the lock here b/c we need to clear
         * all the mappings before the area can be reclaimed
         * by someone else.
         */

Best Regards,
J.