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

Christian Lamparter
2018-11-05T16:06:20Z

On Monday, November 5, 2018 3:27:41 PM CET Andy Shevchenko wrote:
> 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.
Ok, will do. I'll sent a v2 later this week.

> Also, it's possible to use (though better to check) dwc->chan.chan_id,
> though I dunno if it's reliable.
dwc->chan.chan_id is subjected to the chan_allocation setting.
So, if it's set to CHAN_ALLOCATION_DESCENDING the dt prop array values
for the protctl would need to be reversed as well in order to match the
other per-channel settings (for example multiblock).
So, let's not do that since this gets very confusing.