linux-kernel - Re: [RFC v02 04/15] dmaengine: edma: Add support for DMA filter mapping to slave devices

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4013235.sXCFUFy4j4@wuerfel>
Date:	Tue, 01 Dec 2015 11:14:29 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Peter Ujfalusi <peter.ujfalusi@...com>
Cc:	vinod.koul@...el.com, andy.shevchenko@...il.com,
	linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org,
	linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-mmc@...r.kernel.org, nsekhar@...com,
	linux-spi@...r.kernel.org
Subject: Re: [RFC v02 04/15] dmaengine: edma: Add support for DMA filter mapping to slave devices

On Tuesday 01 December 2015 11:58:53 Peter Ujfalusi wrote:
> On 11/30/2015 04:11 PM, Arnd Bergmann wrote:
> > On Monday 30 November 2015 15:45:34 Peter Ujfalusi wrote:
> >> @@ -2428,6 +2436,22 @@ bool edma_filter_fn(struct dma_chan *chan, void *param)
> >>  }
> >>  EXPORT_SYMBOL(edma_filter_fn);
> >>  
> >> +static bool edma_filter_for_map(struct dma_chan *chan, void *param)
> >> +{
> >> +       bool match = false;
> >> +
> >> +       if (chan->device->dev->driver == &edma_driver.driver) {
> >> +               struct edma_chan *echan = to_edma_chan(chan);
> >> +               unsigned ch_req = (unsigned)param;
> >> +               if (ch_req == echan->ch_num) {
> >> +                       /* The channel is going to be used as HW synchronized */
> >> +                       echan->hw_triggered = true;
> >> +                       match = true;
> >> +               }
> >> +       }
> >> +       return match;
> >> +}
> >> +
> >>  static int edma_init(void)
> >>
> > 
> > I don't see the difference between edma_filter_fn and edma_filter_for_map.
> > Why do you need both?
> 
> edma_filter_fn:
>         unsigned ch_req = *(unsigned *)param;
> 
> edma_filter_for_map:
>         unsigned ch_req = (unsigned)param;

I see.

> If I want to reuse the edma_filter_fn, I would need an unsigned array for the
> eDMA event numbers in the board files to be able to provide the pointer to
> each of them.

How about this:

#define EDMA_CTLR_CHANP(ctlr, chan)      ((const int[]){ [0] = ((ctlr) << 16) | (chan)})

static struct dma_filter_map da830_edma_map[] = {
         { "davinci-mcasp.0", "rx", EDMA_CTLR_CHANP(0, 0)},
         { "davinci-mcasp.0", "tx", EDMA_CTLR_CHANP(0, 1)},
         { "davinci-mcasp.1", "rx", EDMA_CTLR_CHANP(0, 2)},
         ...
};

That way, you create an anonymous constant integer expression and the data
points to that.

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/