linux-kernel - Re: [PATCH v4 3/3] dma: Add Freescale eDMA engine driver support

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]

Date:	Mon, 2 Sep 2013 16:42:00 +0530
From:	Vinod Koul <vinod.koul@...el.com>
To:	Lu Jingchang-B35083 <B35083@...escale.com>
Cc:	"shawn.guo@...aro.org" <shawn.guo@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH v4 3/3] dma: Add Freescale eDMA engine driver support

On Mon, Sep 02, 2013 at 07:32:53AM +0000, Lu Jingchang-B35083 wrote:
> > > > > > > +	chan->private = fn_param;
> > > > > > why do you need to use chan->private?
> > > > > [Lu Jingchang]
> > > > > The private used here is to store the slot_id information, which
> > must
> > > > be used
> > > > > by the DMAMUX in alloc_chan_resources function. Thanks.
> > > > Why dont you pass this in struct dma_slave_config memeber slave_id
> > for
> > > > this.
> > > [Lu Jingchang-b35083]
> > > I will drop this private and setup the slave_id directly in the filter
> > function.
> > why in filter? before calling prepare function you can set the slave
> > config
> How about change the filter_fn to follow:
> static bool fsl_edma_filter_fn(struct dma_chan *chan, void *fn_param)
> {
>         struct fsl_edma_filter_param *fparam = fn_param;
>         struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
>         unsigned char val;
> 
>         if (fsl_chan->edmamux->mux_id != fparam->mux_id)
>                 return false;
> 
>         val = EDMAMUX_CHCFG_ENBL | EDMAMUX_CHCFG_SOURCE(fparam->slot_id);
>         fsl_edmamux_config_chan(fsl_chan, val);
>         return true;
> }
> In fact the slot_id isn't need elsewhere, and if the filter return true, 
> This channel should be to this request. So no need to save the slave id, Right?
something like

static bool fsl_edma_filter_fn(struct dma_chan *chan, void *fn_param)
{
	struct fsl_edma_filter_param *fparam = fn_param;
	struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);

	if (fsl_chan->edmamux->mux_id != fparam->mux_id)
		return false;
	return true;
}

in thedriver which calls this:

before prep:

	config->slave_id = val;

	dma_set_slave_config(chan, slave);

~Vinod
--
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/