Messages in this thread | | | Date | Mon, 04 Feb 2013 21:22:42 +0300 | From | Sergei Shtylyov <> | Subject | Re: [PATCH v7 01/10] ARM: davinci: move private EDMA API to arm/common |
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Hello.
On 02/04/2013 08:02 PM, Felipe Balbi 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.
Utter nonsense, CPPI 4.1 is hardware abstract DMA engine. It's used for Ethernet transfers on out-of-tree platforms like mach-avalanche/.
>> 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 ?
My efforts stopped to be funded by MV back in 2010. Hell, I'm not even working in MV as I used to, hanging on the verge of my current contract being terminated.
>>>> 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
There was a patch, it only needed comments addressed. I think the author was Heikki Krogerus. As for me, my time is very limited, so be thankful even for those scarce patches I'm sending out now -- I'm doing them in my copious free time.
WBR, Sergei
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