[U-Boot] [PATCH] nios2: convert cache flush to use dm cpu data

[Ley Foon Tan]

On Fri, Oct 9, 2015 at 5:39 AM, Marek Vasut <marex at denx.de> wrote:

>> +
>> +DECLARE_GLOBAL_DATA_PTR;
>> +
>> +static void __flush_dcache_all(unsigned long start, unsigned long end)
>> +{
>> +     unsigned long addr;
>> +
>> +     start &= ~(gd->arch.dcache_line_size - 1);
>
> I'd suggest to use GENMASK() here, but I don't think we picked this from Linux
> just yet.
>
>> +     end += (gd->arch.dcache_line_size - 1);
>> +     end &= ~(gd->arch.dcache_line_size - 1);
>
> Is this an attempt at poor-mans' rounding ? I think you want to implment
> something like arch/arm/cpu/arm926ejs/cache.c check_cache_range() and NOT
> do any rounding here. The reason for that is that if you do rounding, you
> might accidentally corrupt a piece of memory which was just delivered via
> DMA before you did the flush.
The code above is to convert the address to dcache line size.
arch/arm/cpu/arm926ejs/cache.c check_cache_range() will skip the cache
flushing if it is unaligned to cache line size. I'm not sure how
frequent U-boot access to non-aligned cache line size.

Regards
Ley Foon