Re: DMA API issues

From: Ian Molton
Date: Fri Jun 18 2004 - 14:08:18 EST


On 18 Jun 2004 13:52:46 -0500
James Bottomley <James.Bottomley@xxxxxxxxxxxx> wrote:

>
> You still haven't explained what you want to do though. Apart from the
> occasional brush with usbstorage, I don't have a good knowledge of the
> layout of the USB drivers. I assume you simply want to persuade the
> ohci driver to use your memory area somehow, but what do you actually
> want the ohci driver to do with it? And how much leeway do you get to
> customise the driver.


In *theory* the OHCI driver is doing everything right - its asking for DMAable memory and using it. if the DMA api simply understood the device in question, and alocated accordingly, it would just work.

there are two solutions:

1) Break up the OHCI driver and make it into a chip driver as you describe
2) Make the DMA API do the right thing with these devices

1) means everyone gets to write their own allocator - not pretty
2) means we get to share code and it all just works.
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