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Re: [PATCH 1/2] dmaengine: TXx9 Soc DMA Controller driver

To: dan.j.williams@intel.com
Subject: Re: [PATCH 1/2] dmaengine: TXx9 Soc DMA Controller driver
From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Date: Wed, 18 Mar 2009 11:01:54 +0900 (JST)
Cc: linux-mips@linux-mips.org, ralf@linux-mips.org, linux-kernel@vger.kernel.org, haavard.skinnemoen@atmel.com
In-reply-to: <e9c3a7c20903171823g1e6c42b9t5f042d550a6ddd47@mail.gmail.com>
Organization: TOSHIBA Personal Computer System Corporation
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <e9c3a7c20903171002n50964148v8366fa2f00e3164c@mail.gmail.com> <20090318.094935.238694196.nemoto@toshiba-tops.co.jp> <e9c3a7c20903171823g1e6c42b9t5f042d550a6ddd47@mail.gmail.com>
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On Tue, 17 Mar 2009 18:23:46 -0700, Dan Williams <dan.j.williams@intel.com> 
wrote:
> Now, back to the issue at hand.  Does your driver still need direct
> control over chan->chan_id, or can it now rely on the fact that
> dma_async_device_register() will fail if a channel is not initialized?
>  Or, just use some platform_data to identify the channel in the same
> manner as atmel-mci?

Yes, I still want to control chan->chan_id.

The atmel-mci does not select "channel".  It just pick the first
usable channel of the dma_device specified by platform_data.  I
suppose dw_dmac is symmetric (it can use any channel for any slave).
But TXx9 SoC DMAC channels are hardwired to each peripheral devices.

And I want to call Channel-3 of DMAC-0 "dma0chan3" even if Channel-2
was assigned to for public memcpy channel.

---
Atsushi Nemoto

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