From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
To: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-arm-kernel@lists.infradead.org, linux@arm.linux.org.uk
Subject: Re: [PATCH 01/28] dmaengine: use DMA_COMPLETE for dma completion status
Date: Thu, 17 Oct 2013 10:27:13 +0200 (CEST) [thread overview]
Message-ID: <Pine.LNX.4.64.1310170851230.27369@axis700.grange> (raw)
In-Reply-To: <20131017020745.GA14013@intel.com>
On Thu, 17 Oct 2013, Vinod Koul wrote:
> On Wed, Oct 16, 2013 at 11:45:48AM -0700, Dan Williams wrote:
> > On Wed, Oct 16, 2013 at 11:29 AM, Guennadi Liakhovetski
> > >
> > > Doesn't this break kernel compilation for a total of 27 commits? Or am I
> > > missing anything?
> >
> > Yes, I think at the start DMA_COMPLETE should just be a alias for
> > DMA_SUCCESS, then after all the driver renames are in delete
> > DMA_SUCCESS.
> Oops, taht was bad of me. ffixes in v2 and sending patch 29 for removal case
Ok, yes, this should work now. I'm wondering though - is DMA_COMPLTE
really a better name? AFAICS, we can only differentiate between 2
possibilities with the current API: a transfer is "in progress" - between
last used and last completed, and "unknown" - either completed, or
aborted, or not yet submitted - if the cookie is larger, than last
completed and we assume, that it has wrapped.
Actually for a driver, that I'm currently working on, I implemented a
cache of N last cookies (e.g. 128), which is a bitfield, where I just
record a 1, if that descriptor has failed, and a 0, if completed
successfully. That way I can report one of 4 states: cookie on queue,
completed successfully, failed, unknown. I'm not sure, whether I'll keep
this in the final version, this doesn't really fit the present dmaengine
API concept. We could make this generic, if desired. Otherwise your
proposed error callback should help too. But in either case I think with
the current implementation we cannot find out whether a specific cookie
completed successfully or failed.
One more observation: I looked at a couple of drivers, using the DMA_ERROR
state. E.g. mmp_tdma.c, mxs-dma.c. They store errors in a .status field in
their private data. Then they return that status in their
.device_tx_status() methods - independent on the cookie! This doesn't look
right to me... at_hdmac.c does something similarly strange.
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
next prev parent reply other threads:[~2013-10-17 8:27 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-16 16:28 [PATCH 00/28]: " Vinod Koul
2013-10-16 16:28 ` [PATCH 01/28] " Vinod Koul
2013-10-16 18:29 ` Guennadi Liakhovetski
2013-10-16 18:45 ` Dan Williams
2013-10-17 2:07 ` Vinod Koul
2013-10-17 8:27 ` Guennadi Liakhovetski [this message]
2013-10-17 9:53 ` Vinod Koul
2013-10-17 14:27 ` Sebastian Andrzej Siewior
2013-10-17 13:48 ` Vinod Koul
2013-10-24 21:28 ` Guennadi Liakhovetski
2013-10-25 4:23 ` Vinod Koul
2013-10-25 6:32 ` Guennadi Liakhovetski
2013-10-25 5:43 ` Vinod Koul
2013-10-25 6:43 ` Guennadi Liakhovetski
2013-10-29 16:47 ` Olof Johansson
2013-10-30 13:03 ` Vinod Koul
2013-11-04 12:51 ` Sebastian Andrzej Siewior
2013-11-11 19:13 ` Olof Johansson
2013-11-12 4:00 ` Vinod Koul
2013-11-12 5:11 ` Olof Johansson
2013-11-12 4:47 ` Vinod Koul
2013-10-17 14:39 ` Guennadi Liakhovetski
2013-10-16 16:28 ` [PATCH 02/28] dmaengine: amba-pl08x: " Vinod Koul
2013-10-16 16:28 ` [PATCH 03/28] dmaengine: at_hdma: " Vinod Koul
2013-10-17 8:08 ` Nicolas Ferre
2013-10-16 16:28 ` [PATCH 04/28] dmaengine: coh901318: " Vinod Koul
2013-10-16 16:28 ` [PATCH 05/28] dmaengine: cppi41: " Vinod Koul
2013-10-16 16:28 ` [PATCH 06/28] dmaengine: jz4740: " Vinod Koul
2013-10-16 16:28 ` [PATCH 07/28] dmaengine: dmatest: " Vinod Koul
2013-10-16 16:28 ` [PATCH 08/28] dmaengine: dw: " Vinod Koul
2013-10-17 13:43 ` Andy Shevchenko
2013-10-21 7:33 ` Viresh Kumar
2013-10-16 16:28 ` [PATCH 09/28] dmaengine: edma: " Vinod Koul
2013-10-17 0:31 ` Joel Fernandes
2013-10-16 16:28 ` [PATCH 10/28] dmaengine: imx-dma: " Vinod Koul
2013-10-16 16:28 ` [PATCH 11/28] dmaengine: imx-sdma: " Vinod Koul
2013-10-16 16:28 ` [PATCH 12/28] dmaengine: intel_mid_dma: " Vinod Koul
2013-10-16 16:28 ` [PATCH 13/28] dmaengine: ioat: " Vinod Koul
2013-10-16 16:28 ` [PATCH 14/28] dmaengine: iop: " Vinod Koul
2013-10-16 16:28 ` [PATCH 15/28] dmaengine: k3dma: " Vinod Koul
2013-10-17 14:18 ` zhangfei gao
2013-10-16 16:28 ` [PATCH 16/28] dmaengine: mmp_tdma: " Vinod Koul
2013-10-17 14:19 ` zhangfei gao
2013-10-16 16:28 ` [PATCH 17/28] dmaengine: mv_xor: " Vinod Koul
2013-10-16 16:28 ` [PATCH 18/28] dmaengine: mxs-dma: " Vinod Koul
2013-10-16 16:28 ` [PATCH 19/28] dmaengine: omap: " Vinod Koul
2013-10-16 16:28 ` [PATCH 20/28] dmaengine: ppc4xx: " Vinod Koul
2013-10-16 16:28 ` [PATCH 21/28] dmaengine: sa11x0: " Vinod Koul
2013-10-16 16:28 ` [PATCH 22/28] dmaengine: sh: " Vinod Koul
2013-10-16 16:28 ` [PATCH 23/28] dmaengine: ste: " Vinod Koul
2013-10-16 16:28 ` [PATCH 24/28] dmaengine: tegra: " Vinod Koul
2013-10-16 16:28 ` [PATCH 25/28] dmaengine: txx9: " Vinod Koul
2013-10-16 16:28 ` [PATCH 26/28] async_tx: " Vinod Koul
2013-10-16 16:28 ` [PATCH 27/28] serial: sh: " Vinod Koul
2013-10-16 20:17 ` Greg Kroah-Hartman
2013-10-16 16:28 ` [PATCH 28/28] net: " Vinod Koul
2013-10-17 2:16 ` [PATCH 29/29] dmaengine: remove unused DMA_SUCCESS Vinod Koul
2013-10-17 4:55 ` [PATCH 28/28] net: use DMA_COMPLETE for dma completion status David Miller
2013-10-17 9:00 ` [PATCH 00/28]: dmaengine: " Linus Walleij
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