On 5/20/22 00:22, Andrew Morton wrote:
> On Thu, 19 May 2022 16:25:50 +0800 Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:
>
>> Add special hook for architecture to verify or setup addr, size
>> or prot when ioremap() or iounmap(), which will make the generic
>> ioremap more useful.
>>
>> arch_ioremap() return a pointer,
>> - IS_ERR means return an error
>> - NULL means continue to remap
>> - a non-NULL, non-IS_ERR pointer is directly returned
>> arch_iounmap() return a int value,
>> - 0 means continue to vunmap
>> - error code means skip vunmap and return directly
>>
>> ...
>>
>> --- a/include/asm-generic/io.h
>> +++ b/include/asm-generic/io.h
>> @@ -964,6 +964,30 @@ static inline void iounmap(volatile void __iomem *addr)
>> #elif defined(CONFIG_GENERIC_IOREMAP)
>> #include <linux/pgtable.h>
>>
>> +/*
>> + * Arch code can implement the following two special hooks when using GENERIC_IOREMAP
>> + * arch_ioremap() return a pointer,
>> + * - IS_ERR means return an error
>> + * - NULL means continue to remap
>> + * - a non-NULL, non-IS_ERR pointer is returned directly
>> + * arch_iounmap() return a int,
>> + * - 0 means continue to vunmap
>> + * - error code means skip vunmap and return directly
>> + */
>> +#ifndef arch_ioremap
>> +static inline void __iomem *arch_ioremap(phys_addr_t phys_addr, size_t size, unsigned long prot)
>> +{
>> + return NULL;
>> +}
>
> Maybe should do
>
> #define arch_ioremap arch_ioremap
>
> here
>
>> +#endif
>> +
>> +#ifndef arch_iounmap
>> +static inline int arch_iounmap(void __iomem *addr)
>> +{
>> + return 0;
>> +}
>
> and here.
>
> It shouldn't matter a lot because this file has inclusion guards.
> However it seems tidier and perhaps other code will want to know
> whether this was defined. Dunno.
+1, agreed.
