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Message-ID: <5587F1F4.1060905@ti.com>
Date: Mon, 22 Jun 2015 14:31:00 +0300
From: Peter Ujfalusi <peter.ujfalusi@...com>
To: Vinod Koul <vinod.koul@...el.com>
CC: Geert Uytterhoeven <geert@...ux-m68k.org>,
Tony Lindgren <tony@...mide.com>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Dan Williams <dan.j.williams@...el.com>,
<dmaengine@...r.kernel.org>,
"linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>,
"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
Linux MMC List <linux-mmc@...r.kernel.org>,
<linux-crypto@...r.kernel.org>,
linux-spi <linux-spi@...r.kernel.org>,
Linux Media Mailing List <linux-media@...r.kernel.org>,
ALSA Development Mailing List <alsa-devel@...a-project.org>
Subject: Re: [PATCH 02/13] dmaengine: Introduce
dma_request_slave_channel_compat_reason()
On 06/12/2015 03:58 PM, Vinod Koul wrote:
> Sorry this slipped thru
I was away for a week anyways ;)
> Thinking about it again, I think we should coverge to two APIs and mark the
> legacy depracuated and look to convert folks and phase that out
Currently, w/o this series we have these APIs:
/* to be used with DT/ACPI */
dma_request_slave_channel(dev, name) /* NULL on failure */
dma_request_slave_channel_reason(dev, name) /* error code on failure */
/* Legacy mode only - no DT/ACPI lookup */
dma_request_channel(mask, fn, fn_param) /* NULL on failure */
/* to be used with DT/ACPI or legacy boot */
dma_request_slave_channel_compat(mask, fn, fn_param, dev, name) /* NULL on
failure */
To request _any_ channel to be used for memcpy one has to use
dma_request_channel(mask, NULL, NULL);
If I did not missed something.
As we need different types of parameters for DT/ACPI and legacy (non DT/ACPI
lookup) and the good API names are already taken, we might need to settle:
/* to be used with DT/ACPI */
dma_request_slave_channel(dev, name) /* error code on failure */
- Convert users to check IS_ERR_OR_NULL() instead against NULL
- Mark dma_request_slave_channel_reason() deprecated and convert the current users
/* to be used with DT/ACPI or legacy boot */
dma_request_slave_channel_compat(mask, fn, fn_param, dev, name) /* error code
on failure */
- Convert users to check IS_ERR_OR_NULL() instead against NULL
- Do not try legacy mode if either OF or ACPI failed because of real error
/* Legacy mode only - no DT/ACPI lookup */
dma_request_channel_legacy(mask, fn, fn_param) /* error code on failure */
- convert users of dma_request_channel()
- mark dma_request_channel() deprecated
/* to be used to get a channel for memcpy for example */
dma_request_any_channel(mask) /* error code on failure */
- Convert current dma_request_channel(mask, NULL, NULL) users
I know, any of the other function could be prepared to handle this when
parameters are missing, but it is a bit cleaner to have separate API for this.
It would be nice to find another name for the
dma_request_slave_channel_compat() so with the new name we could have chance
to rearrange the parameters: (dev, name, mask, fn, fn_param)
We would end up with the following APIs, all returning with error code on failure:
dma_request_slave_channel(dev, name);
dma_request_channel_legacy(mask, fn, fn_param);
dma_request_slave_channel_compat(mask, fn, fn_param, dev, name);
dma_request_any_channel(mask);
What do you think?
--
Péter
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