Re: [PATCH v1 2/2] dmaengine: dw: implement per-channel protection control setting

Andy Shevchenko
2018-11-05T14:27:41Z

On Mon, Nov 05, 2018 at 04:22:54PM +0200, Andy Shevchenko wrote:
> On Sun, Nov 04, 2018 at 06:01:39PM +0100, Christian Lamparter wrote:

> > + struct dw_dma *dw = to_dw_dma(dwc->chan.device);
> > + size_t chanidx = (size_t)(dwc - dw->chan);
>
> We have mask field, so, index is a first set bit out of mask, __ffs(mask).
>
> unsigned int protctl = dw->pdata->protctl[__ffs(mask)];

dwc->mask, of course.

Also, it's possible to use (though better to check) dwc->chan.chan_id, though I
dunno if it's reliable.

--
With Best Regards,
Andy Shevchenko