Messages in this thread |  | | | Date | Sat, 21 Mar 2009 21:29:20 +0900 (JST) | | Subject | Re: [PATCH 1/2] dmaengine: TXx9 Soc DMA Controller driver | | From | Atsushi Nemoto <> |
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On Wed, 18 Mar 2009 10:26:13 -0700, Dan Williams <dan.j.williams@intel.com> wrote: > > 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). > > You are right, it does not hardwire the channel, but it does hardwire > the device, see at32_add_device_mci [1]. > > > But TXx9 SoC DMAC channels are hardwired to each peripheral devices. > > I think creating a dma_device instance per channel and specifying that > device like atmel-mci is the more future-proof way to go.
Well, I have considered it but it looks overkill for me at that time. Maybe time to think again...
> > And I want to call Channel-3 of DMAC-0 "dma0chan3" even if Channel-2 > > was assigned to for public memcpy channel. > > The problem is you could pass in the chan_id to guarantee 'chan3', but > there is no guarantee that you will get 'dma0', as the driver has no > knowledge of what other dma devices may be in the system.
Yes, I do not expect 'dma0'. My filter function uses dev_name(chan->device->dev), which is "txx9dmac.0" in this case.
Anyway, "one dma-device per channel" manner will make things much simpler.
--- Atsushi Nemoto -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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