2017-10-11 16:39 GMT+02:00 Arnd Bergmann <[email protected]>: > On Wed, Oct 11, 2017 at 4:27 PM, Benjamin Gaignard > <[email protected]> wrote: >> 2017-10-11 16:01 GMT+02:00 Arnd Bergmann <[email protected]>: >> >>> @@ -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))
That sound better for me since it doesn't limit the code to 32 bits architecture > > or we could combined it with the check above: > > if ((((buf_len | addr) & (max_width - 1)) == 0) && > (tlen >= max_width)) No it is more simple to read with two checks Benjamin > > Arnd
