From: Vinod Koul <vinod.koul@intel.com>
To: Jassi Brar <jaswinder.singh@linaro.org>
Cc: linux-kernel@vger.kernel.org, "Bounine,
Alexandre" <Alexandre.Bounine@idt.com>,
Dan <dan.j.williams@intel.com>,
linuxppc-dev@lists.ozlabs.org, akpm@linux-foundation.org
Subject: Re: [RFC PATCH 1/2] RapidIO: Add DMA Engine support for RIO data transfers
Date: Mon, 17 Oct 2011 22:31:24 +0530 [thread overview]
Message-ID: <1318870884.23438.174.camel@vkoul-udesk3> (raw)
In-Reply-To: <CAJe_ZhdjMTsqSTDwV_zaAQKmCbjOtRVc951wxqKScaCR-DBG9Q@mail.gmail.com>
On Mon, 2011-10-17 at 21:22 +0530, Jassi Brar wrote:
> On 15 October 2011 23:05, Vinod Koul <vinod.koul@intel.com> wrote:
>
> > Another alternate approach could be to add one more argument to
> > prep_slave_sg API which allows us to pass additional runtime specific
> > parameters. This can be NULL and unused for existing drivers and used in
> > RIO and any future subsystems which want to use dmaengine.
> > Thoughts...?
> >
> That doesn't sound much different than passing the data via
> dma_chan.private during prep_slave_sg. Only now we add to
> the number of arguments.
Yes agreed, but we already decided and marked it as depreciated.
> And then either this argument would be RapidIO specific (unfair
> to other users) or generic. In latter case what would it look like ?
My initial thoughts were to add an argument which only the specific dmac
knows howto decode and is filled by its client. As i said for existing
users and people who don't require dynamic information wouldn't bother.
The pros
- allows us to support RIO kind of subsystems where one needs to pass
subsystem specific information for programing the dmac
- doesn't require us to add subsystem specific stuff in dmaengine,
today its RIO tomorrow some other folks may want to add. We want to
maintain dmaengine as a generic framework, while also trying to support
multiple audiences.
Cons:
- there is no guarantee; dmac expects foo and clients pass bar
I am okay if we have alternate way to support this with above goal :)
--
~Vinod
next prev parent reply other threads:[~2011-10-17 17:10 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-30 21:38 [RFC PATCH 1/2] RapidIO: Add DMA Engine support for RIO data transfers Alexandre Bounine
2011-09-30 21:38 ` [RFC PATCH 2/2 -mm] RapidIO: TSI721 Add DMA Engine support Alexandre Bounine
2011-09-30 22:15 ` Andrew Morton
2011-10-03 17:53 ` Bounine, Alexandre
2011-10-04 21:43 ` Andrew Morton
2011-10-05 1:38 ` Bounine, Alexandre
2011-10-05 1:57 ` Andrew Morton
2011-10-05 2:57 ` Bounine, Alexandre
2011-10-01 18:06 ` Vinod Koul
2011-10-01 18:01 ` [RFC PATCH 1/2] RapidIO: Add DMA Engine support for RIO data transfers Vinod Koul
2011-10-03 16:52 ` Bounine, Alexandre
2011-10-05 20:38 ` Williams, Dan J
2011-10-07 16:12 ` Bounine, Alexandre
2011-10-07 5:27 ` Vinod Koul
2011-10-07 19:08 ` Bounine, Alexandre
2011-10-15 17:35 ` Vinod Koul
2011-10-17 14:33 ` Bounine, Alexandre
2011-10-17 15:52 ` Jassi Brar
2011-10-17 17:01 ` Vinod Koul [this message]
2011-10-17 19:39 ` Bounine, Alexandre
2011-10-17 18:16 ` Bounine, Alexandre
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