2017-11-08 17:04 GMT+08:00 Arnd Bergmann <arnd@xxxxxxxx>:
> On Wed, Nov 8, 2017 at 6:55 AM, Greentime Hu <green.hu@xxxxxxxxx> wrote:
>
>> +
>> +#define ioremap(cookie,size) __ioremap(cookie,size,0,1)
>> +#define ioremap_nocache(cookie,size) __ioremap(cookie,size,0,1)
>> +#define iounmap(cookie) __iounmap(cookie)
>
>> +#include <asm-generic/io.h>
>
> asm-generic/io.h now provides an ioremap_nocache() helper along with
> ioremap_uc/ioremap_wc/ioremap_wt, so I think you can remove the
> ioremap_nocache definition here. You might also be able to remove
> __ioremap and __iounmap, and only provide ioremap/iounmap, plus
> the identity macro 'define ioremap ioremap'
Thanks. I will try to use generic ioremap_nocache() helper in the next
version patch.
>> +void __iomem *__ioremap(unsigned long phys_addr, size_t size,
>> + unsigned long flags, unsigned long align)
>
> The 'align' argument is unused here, and not used on other architectures
> either.
>
Thanks. I will remove this argument in the next version patch.
>> +{
>> + struct vm_struct *area;
>> + unsigned long addr, offset, last_addr;
>> + pgprot_t prot;
>> +
>> + /* Don't allow wraparound or zero size */
>> + last_addr = phys_addr + size - 1;
>> + if (!size || last_addr < phys_addr)
>> + return NULL;
>> +
>> + /*
>> + * Mappings have to be page-aligned
>> + */
>> + offset = phys_addr & ~PAGE_MASK;
>> + phys_addr &= PAGE_MASK;
>> + size = PAGE_ALIGN(last_addr + 1) - phys_addr;
>> +
>> + /*
>> + * Ok, go for it..
>> + */
>> + area = get_vm_area(size, VM_IOREMAP);
>
> Better use get_vm_area_caller here to have the ioremap areas show up
> in a more useful form in /proc/vmallocinfo
Thanks.
I will use get_vm_area_caller() in the next version patch.
> Please also have a look at what you can do for memremap().
>
> Since you have no cacheable version of ioremap_wb/wt, it will
> return an uncached mapping all the time, which is not ideal.
Thanks.
I will study kernel/memremap.c
