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From: Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>
To: Andy Shevchenko
	<andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Stanimir Varbanov
	<stanimir.varbanov-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Andy Gross <agross-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Sagar Dharia <sdharia-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Daniel Sneddon <dsneddon-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Subject: Re: [PATCH v4] spi: qup: Add DMA capabilities
Date: Sun, 08 Mar 2015 12:21:34 +0100	[thread overview]
Message-ID: <54FC30BE.1070606@metafoo.de> (raw)
In-Reply-To: <CAHp75VeYanNJrEyTtcxb5g5DB8=609nebgZm8zVAeJdmSgHjkQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On 03/07/2015 08:43 PM, Andy Shevchenko wrote:
> On Sat, Mar 7, 2015 at 1:21 PM, Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
>> On Wed, Mar 04, 2015 at 12:02:05PM +0200, Stanimir Varbanov wrote:
>>> From: Andy Gross <agross-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
>>>
>>> This patch adds DMA capabilities to the spi-qup driver.  If DMA channels are
>>> present, the QUP will use DMA instead of block mode for transfers to/from SPI
>>> peripherals for transactions larger than the length of a block.
>>
>> Applied, but why is there no devm_dma_request_slave_channel_reason()?
>
> I suppose the answer would be "we have a lot of slightly different
> cases and we have to get rid of current mess with legacy API calls".
> The most problematic stuff now inside DMA slave subsystem is so called
> "filter function". It's a main impediment right now as I understand.

dma_request_slave_channel_reason() is the sane API though and does not use 
the filter functions. Adding a devm version of it seems reasonable.

- Lars
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WARNING: multiple messages have this Message-ID (diff)
From: Lars-Peter Clausen <lars@metafoo.de>
To: Andy Shevchenko <andy.shevchenko@gmail.com>,
	Mark Brown <broonie@kernel.org>
Cc: Stanimir Varbanov <stanimir.varbanov@linaro.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-spi@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Kumar Gala <galak@codeaurora.org>,
	Andy Gross <agross@codeaurora.org>,
	Sagar Dharia <sdharia@codeaurora.org>,
	Daniel Sneddon <dsneddon@codeaurora.org>
Subject: Re: [PATCH v4] spi: qup: Add DMA capabilities
Date: Sun, 08 Mar 2015 12:21:34 +0100	[thread overview]
Message-ID: <54FC30BE.1070606@metafoo.de> (raw)
In-Reply-To: <CAHp75VeYanNJrEyTtcxb5g5DB8=609nebgZm8zVAeJdmSgHjkQ@mail.gmail.com>

On 03/07/2015 08:43 PM, Andy Shevchenko wrote:
> On Sat, Mar 7, 2015 at 1:21 PM, Mark Brown <broonie@kernel.org> wrote:
>> On Wed, Mar 04, 2015 at 12:02:05PM +0200, Stanimir Varbanov wrote:
>>> From: Andy Gross <agross@codeaurora.org>
>>>
>>> This patch adds DMA capabilities to the spi-qup driver.  If DMA channels are
>>> present, the QUP will use DMA instead of block mode for transfers to/from SPI
>>> peripherals for transactions larger than the length of a block.
>>
>> Applied, but why is there no devm_dma_request_slave_channel_reason()?
>
> I suppose the answer would be "we have a lot of slightly different
> cases and we have to get rid of current mess with legacy API calls".
> The most problematic stuff now inside DMA slave subsystem is so called
> "filter function". It's a main impediment right now as I understand.

dma_request_slave_channel_reason() is the sane API though and does not use 
the filter functions. Adding a devm version of it seems reasonable.

- Lars

  parent reply	other threads:[~2015-03-08 11:21 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-04 10:02 [PATCH v4] spi: qup: Add DMA capabilities Stanimir Varbanov
2015-03-04 10:02 ` Stanimir Varbanov
2015-03-06 14:38 ` Ivan T. Ivanov
2015-03-07 11:21 ` Mark Brown
2015-03-07 19:43   ` Andy Shevchenko
     [not found]     ` <CAHp75VeYanNJrEyTtcxb5g5DB8=609nebgZm8zVAeJdmSgHjkQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-03-08 11:21       ` Lars-Peter Clausen [this message]
2015-03-08 11:21         ` Lars-Peter Clausen
2015-03-08 12:20         ` Andy Shevchenko
2015-03-09  9:12           ` Lars-Peter Clausen

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