Thanks Russell!
On 16 March 2014 02:46, Russell King - ARM Linux linux@arm.linux.org.uk wrote:
On Mon, Mar 10, 2014 at 11:32:17AM -0700, Sebastian Capella wrote:
...
Let's look at the implementations...
#define __pa(x) __virt_to_phys((unsigned long)(x)) static inline phys_addr_t __virt_to_phys(unsigned long x) { return (phys_addr_t)x - PAGE_OFFSET + PHYS_OFFSET; }
So, __pa() returns a phys_addr_t (which may be either 32-bit or 64-bit).
#define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
And that will do an appropriate shift to convert the phys_addr_t to a PFN, which will be fine to assign to an unsigned long variable.
#define __phys_to_pfn(paddr) ((unsigned long)((paddr) >> PAGE_SHIFT))
This does the same thing, but has an explicit cast.
So, the only difference between the two suggestions is that additional cast, which has no effect here.
Sounds good, thanks!
I was a little unsure about the page sizes that could affect all of the implementations.
I'll make this change and repost, basically using virt_to_pfn in place of the previous __pa_symbol, and remove unused declarations.
Thanks again!
Sebastian