Re: [PATCH v7 01/10] ARM: davinci: move private EDMA API to arm/common

Felipe Balbi
2013-02-04T17:02:16Z

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Hi,

On Mon, Feb 04, 2013 at 08:54:17PM +0300, Sergei Shtylyov wrote:
> > On Mon, Feb 04, 2013 at 08:36:38PM +0300, Sergei Shtylyov wrote:
> >>> opted out of it. From the top of my head we have CPPI 3.x, CPPI 4.1,
> >>> Inventra DMA, OMAP sDMA and ux500 DMA engines supported by the driver.
>
> >>> Granted, CPPI 4.1 makes some assumptions about the fact that it's
> >>> handling USB tranfers,
>
> >> What CPPI 4.1 code makes this assumptions? MUSB DMA driver? Then it's just
>
> > HW makes the asumptions
>
> Not true at all. There is a separate set of registers (at offset 0) which
> copes with USB specifics, but CPPI 4.1 itself doesn't know about USB anything.

CPPI 4.1 was made for USB transfers.

> It's just the way the driver was written that it used both sets of registers but
> this needs to be changed into more abstacted accesses to the USB-specific part,
> to cope with it being different on different platfroms, like AM35x. The driver
> as it was last posted, just needs rework now.

are you saying you will do the work ?

> >> Don't know, I was quite content with the abstraction when writing CPPI 4.1
> >> driver for MUSB...
>
> > look closer. The whole:
>
> > if (is_cppi())
> > foo();
> > else if (is_inventra())
> > bar();
> > else if (is_omap_sdma())
> > baz();
>
> > is bogus.
>
> That part -- yes. There were attempt to get rid of this, but without changing
> the DMA API. It was left halfway done after my only critical comment, IIRC. Will
> we ever see the continuation of this effort?

patches are welcome

--
balbi

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