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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: Fri, 13 Mar 2009 01:19:50 +0900 (JST)
Cc: linux-mips@linux-mips.org, ralf@linux-mips.org, linux-kernel@vger.kernel.org, haavard.skinnemoen@atmel.com
In-reply-to: <20090227.002436.106263719.anemo@mba.ocn.ne.jp>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1234538938-23479-1-git-send-email-anemo@mba.ocn.ne.jp> <e9c3a7c20902251745t314c1e0cs114d2199ccc8cf36@mail.gmail.com> <20090227.002436.106263719.anemo@mba.ocn.ne.jp>
Sender: linux-mips-bounce@linux-mips.org
On Fri, 27 Feb 2009 00:24:36 +0900 (JST), Atsushi Nemoto <anemo@mba.ocn.ne.jp> 
wrote:
> > Can you explain how reserved channels work?  It looks like you are
> > working around the generic dma channel allocator, maybe it requires
> > updating to meet your needs.
...
> I need the reserved_chan to make channel 3 named "dma0chan3".  If I
> can chose chan_id for each channels in dma_device, the reserved_chan
> is not needed.

So, how about this?  If it was accepted, I can remove reserved_chan
from txx9dmac driver.

------------------------------------------------------
Subject: dmaengine: Use chan_id provided by DMA device driver
From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>

If chan_id was already given by the DMA device driver, use it.
Otherwise assign an incremental number for each channels.

This allows the DMA device driver to reserve some channel ID numbers.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
---
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 280a9d2..a3679a7 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -609,6 +609,7 @@ EXPORT_SYMBOL(dmaengine_put);
 int dma_async_device_register(struct dma_device *device)
 {
        int chancnt = 0, rc;
+       unsigned int chan_id = 0;
        struct dma_chan* chan;
        atomic_t *idr_ref;
 
@@ -663,7 +664,9 @@ int dma_async_device_register(struct dma_device *device)
                        continue;
                }
 
-               chan->chan_id = chancnt++;
+               if (!chan->chan_id)
+                       chan->chan_id = chan_id++;
+               chancnt++;
                chan->dev->device.class = &dma_devclass;
                chan->dev->device.parent = device->dev;
                chan->dev->chan = chan;

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