linux-kernel - Re: [PATCH RFC 2/2] ARM: pxa: transition to dmaengine phase 1

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: <87wq3hajbc.fsf@free.fr>
Date:	Mon, 16 Feb 2015 17:54:15 +0100
From:	Robert Jarzmik <robert.jarzmik@...e.fr>
To:	Vasily Khoruzhick <anarsoul@...il.com>
Cc:	Vinod Koul <vinod.koul@...el.com>, Arnd Bergmann <arnd@...db.de>,
	Olof Johansson <olof@...om.net>,
	Daniel Mack <zonque@...il.com>,
	Haojian Zhuang <haojian.zhuang@...il.com>,
	dmaengine@...r.kernel.org,
	"linux-kernel\@vger.kernel.org" <linux-kernel@...r.kernel.org>,
	arm-linux <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH RFC 2/2] ARM: pxa: transition to dmaengine phase 1

Vasily Khoruzhick <anarsoul@...il.com> writes:

> On Sun, Feb 15, 2015 at 1:47 AM, Robert Jarzmik <robert.jarzmik@...e.fr> wrote:
>> In order to slowly transition pxa to dmaengine, the legacy code will now
>> rely on dmaengine to request a channel.
>
> Hi Robert,
>
> What about dropping old PXA DMA code completely? Daniel Mack did port
> for most of PXA drivers to dma engine,
> I've rebased his patches against 3.17 several months ago and fixed
> oopses in pxamci and asoc drivers, but I didn't resubmit whole series
> due to lack of time.

Well, it's the last step, yes.
But I want a "smooth transition" : if amongst the ported drivers one starts to
bug, I want to be able to revert _only_ that driver port to dmaengine, and not
_all_ the drivers.

That's the rationale of this patch :
 - phase 1 : enable peacefull coexistence of legacy pxa_request_dma() and
             dmaengine for pxa, for both devicetree and legacy platforms
 - phase 2 : port the drivers, and ensure the work correctly
             This might take a couple of cycles
             Note that phase 1 ensures that submissions can go through each
             maintainer's tree without need for strong consistence.
 - phase 3 : revert the mmp_pdma patch, and drop arch/arm/plat-pxa/dma.c

> My 3.17 tree is at [1], I've tested it on pxa270 machine (Zipit Z2),
> and everything works fine so far. I guess it won't be too much work to
> rebase it against linux-3.20.
Oh, do you volunteer ? That would indeed ease up my burden. I only rebased
pxa3xx_nand, so any help to submit and push is welcome. At least I can commit to
review, and I would concentrate on pxa_camera.c in the meantime.

Cheers.

-- 
Robert
--
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/