On Wed, Oct 11, 2017 at 4:27 PM, Benjamin Gaignard
<benjamin.gaignard@xxxxxxxxxx> wrote:
> 2017-10-11 16:01 GMT+02:00 Arnd Bergmann <arnd@xxxxxxxx>:
>
>> @@ -398,6 +400,9 @@ static enum dma_slave_buswidth stm32_mdma_get_max_width(u32 buf_len, u32 tlen)
>> break;
>> }
>>
>> + if (addr % max_width)
>> + max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
>> +
>
> I'm only half-convince by the implicite 32 bits cast done into
> function prototype.
> If we keep using dma_addr_t and use do_div() instead of %
> does compiler can still optimize the code ?
>
I wouldn't want to add a do_div() here, since it's guaranteed
not to be needed. Would you prefer an explicit cast here
and leave the argument as dma_addr_t?
We could also use a bit mask here like
if (addr & (max_width-1))
or we could combined it with the check above:
if ((((buf_len | addr) & (max_width - 1)) == 0) &&
(tlen >= max_width))
Arnd
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