[PATCH 0/5] ARM: PrimeCell DMA patches v4

[PATCH 0/5] ARM: PrimeCell DMA patches v4

[Linus Walleij]

This is a fourth iteration of the PrimeCell DMA API on top of the
generic DMA devices (sibling to the DMA engine). It's based on
the suggestion from Russell to try and define a specific extension
subset for DMA devices.

Since last iteration the changes are:

- Some necessary extensions to the DMA engine were folded into
  the generic DMA engine framework and are now pending in Dan's
  -next tree.

- I have now also implemented support for the PL022 PrimeCell.

PL011, PL022 and PL180 drivers were tested on the U300 with the
COH 901 318 DMA device.

The PL011 driver was also tested on the U8500 with the pending
DMA40 DMA device.

We're running huge and high-speed transfers on all peripherals.
It works.

Patches will be added to the patch tracker soonish, but if this
is eventually OK:ed by Russell I guess it will have to go in
through Dan's DMA tree. Also Grant has to OK it as maintainer of
the SPI subsystem.

Yours,
Linus Walleij
ST-Ericsson SA

RE: [PATCH 0/5] ARM: PrimeCell DMA patches v4

[Linus WALLEIJ]

[Self]

> This is a fourth iteration of the PrimeCell DMA API on top of the
> generic DMA devices (sibling to the DMA engine). It's based on
> the suggestion from Russell to try and define a specific extension
> subset for DMA devices.

Russell & Grant can you give some hint on the direction you
see for this patch set?

The problem we're facing is that next I will start adding DMA
support for the U8500 and the MMCI derivate found in that platform
doesn't *have* a PIO IRQ, which means the system cannot even
boot without some solid DMA framework in place. (It is currently
unbootable from the released kernels.)

So unless there is some outstanding issue with this approach
we pretty much need this now to keep working on mainlining
the U8500.

I would very much like to have the DMA patches for PrimeCell
support pushed through Dan's tree, but that requires your ACKs
of course, and it will inevitably collide with other PrimeCell
patches for the next merge window (many submitted by myself
admittedly).

I can feed all the PrimeCell stuff to Dan if all agree that this
is a good approach. Another approach is to apply the latest
patches from Dan's tree to ARM and SPI alike and then feed
the PrimeCell stuff through the ARM tree.

Yours,
Linus Walleij

Re: [PATCH 0/5] ARM: PrimeCell DMA patches v4

[Grant Likely]

On Tue, Mar 30, 2010 at 3:57 AM, Linus WALLEIJ
<linus.walleij@stericsson.com> wrote:
> [Self]
>
>> This is a fourth iteration of the PrimeCell DMA API on top of the
>> generic DMA devices (sibling to the DMA engine). It's based on
>> the suggestion from Russell to try and define a specific extension
>> subset for DMA devices.
>
> Russell & Grant can you give some hint on the direction you
> see for this patch set?
>
> The problem we're facing is that next I will start adding DMA
> support for the U8500 and the MMCI derivate found in that platform
> doesn't *have* a PIO IRQ, which means the system cannot even
> boot without some solid DMA framework in place. (It is currently
> unbootable from the released kernels.)
>
> So unless there is some outstanding issue with this approach
> we pretty much need this now to keep working on mainlining
> the U8500.
>
> I would very much like to have the DMA patches for PrimeCell
> support pushed through Dan's tree, but that requires your ACKs
> of course, and it will inevitably collide with other PrimeCell
> patches for the next merge window (many submitted by myself
> admittedly).
>
> I can feed all the PrimeCell stuff to Dan if all agree that this
> is a good approach. Another approach is to apply the latest
> patches from Dan's tree to ARM and SPI alike and then feed
> the PrimeCell stuff through the ARM tree.

I have no objections to the SPI driver getting merged via Dan's tree.

g.