From: Linus Walleij on
2010/7/28 Dan Williams <dan.j.williams(a)intel.com>:
> On Tue, Jun 29, 2010 at 4:36 AM, Linus Walleij
> <linus.walleij(a)stericsson.com> wrote:
>> This creates a DMAengine driver for the ARM PL080/PL081 PrimeCells
>> based on the implementation earlier submitted by Peter Pearse.
>> This is working like a charm for memcpy and slave DMA to the PL011
>> PrimeCell on the PB11MPCore.
>
> Russell I am assuming this implementation and testing is sufficient to
> allay your prior nak [1]? �Linus is oversubscribing virtual channels
> to physical channels to handle muxing.

I don't think Russell has ever NAK:ed the PL08x driver(s). The NAK
was about the PrimeCell DMA extenstions to amba-pl011.c etc.
(Still I'm happy if Russell looks at this thing of course.)

This patch along with the generic channel control removed the
cross-dependency between the PrimeCell DMA patchset and the
drivers/dma DMA engine framework (yay!) so there is no arch/arm
or AMBA stuff involved anymore, other than the fact that this driver
sits on the AMBA/PrimeCell bus.

>> +#ifdef MODULE
>> +
>> +# error "AMBA PL08X DMA CANNOT BE COMPILED AS A LOADABLE MODULE AT PRESENT"
>> +
>> +/*
>> + � � � a) Some devices might make use of DMA during boot
>> + � � � � �(esp true for DMAENGINE implementation)
>> + � � � b) Memory allocation will need much more attention
>> + � � � � �before load/unload can be supported
>> + */
>> +#endif
>
> This is taken care of by being "config bool", but I assume you want
> this for documentation purposes?

Peter had that in and I didn't remove it. If you don't like it you
can remove it or I can send a new patch.

>> + � � � txd = kzalloc(sizeof(struct pl08x_txd), GFP_KERNEL);
>
> ...appears in the prep routines. �Will this driver be used by any
> storage controllers on the platfom? �Might we deadlock waiting on i/o
> that needs to allocate a descriptor to complete?

I haven't noticed anything but a descriptor pool is on my
list of things to look into and fix.

Yours,
Linus Walleij
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From: Dan Williams on
On Wed, Jul 28, 2010 at 4:12 PM, Linus Walleij
<linus.ml.walleij(a)gmail.com> wrote:
> 2010/7/28 Dan Williams <dan.j.williams(a)intel.com>:
>>> + � � � txd = kzalloc(sizeof(struct pl08x_txd), GFP_KERNEL);
>>
>> ...appears in the prep routines. �Will this driver be used by any
>> storage controllers on the platfom? �Might we deadlock waiting on i/o
>> that needs to allocate a descriptor to complete?
>
> I haven't noticed anything but a descriptor pool is on my
> list of things to look into and fix.

If there is a list of things to fix and no acked-by's from anyone on
the cc list I assume you want to wait for 2.6.37?? I'm sending the
dmaengine/async_tx pull request this Friday.

--
Dan
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From: Linus Walleij on
2010/8/4 Dan Williams <dan.j.williams(a)intel.com>:

> If there is a list of things to fix and no acked-by's from anyone on
> the cc list I assume you want to wait for 2.6.37?? �I'm sending the
> dmaengine/async_tx pull request this Friday.

There are no blockers for merging this AFAICT, but some ACK:s would
be nice of course.

Peter, Alessandro and Viresh especially: you will hopefully use this
driver for ARM refboards, Nomadik and SPEAr, can you provide
an Acked-by:?

Yours,
Linus Walleij
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From: Linus Walleij on
2010/8/5 Alessandro Rubini <rubini(a)unipv.it>:

>> Peter, Alessandro and Viresh especially: you will hopefully use this
>> driver for ARM refboards, Nomadik and SPEAr, can you provide
>> an Acked-by:?
>
> I'm sorry I can't test it these times, I must delay stuff to
> the last week of August.

That's be a Tested-by: tag, Acked-by: was more about whether you
think it looks sane I believe, see Documentation/SubmittingPatches.

Yours,
Linus Walleij
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From: viresh kumar on
On Tue, Jun 29, 2010 at 5:06 PM, Linus Walleij
<linus.walleij(a)stericsson.com> wrote:
> This creates a DMAengine driver for the ARM PL080/PL081 PrimeCells
> based on the implementation earlier submitted by Peter Pearse.
> This is working like a charm for memcpy and slave DMA to the PL011
> PrimeCell on the PB11MPCore.
>
> This DMA controller is used in mostly unmodified form in the ARM
> RealView and Versatile platforms, in the ST-Ericsson Nomadik, and
> in the ST SPEAr platform.
>
> It has been converted to use the header from the Samsung PL080
> derivate instead of its own defintions. The Samsungs have a custom
> driver in their mach-* folders though, atleast we can share the
> register definitions.
>
> Cc: Peter Pearse <peter.pearse(a)arm.com>
> Cc: Ben Dooks <ben-linux(a)fluff.org>
> Cc: Kukjin Kim <kgene.kim(a)samsung.com>
> Cc: Alessandro Rubini <rubini(a)unipv.it>
> Cc: Viresh Kumar <viresh.kumar(a)st.com>
> Signed-off-by: Linus Walleij <linus.walleij(a)stericsson.com>
> ---
> Changes since last revision: this has now been successfully tested
> with PL011 UART on the PB11MPCore.
>
> It now uses the generic runtime slave control and not the PrimeCell
> extensions, and thus depends only on that patch set. With the previous
> patch to the header file this is cleanly separated from the ARM tree
> and any PrimeCell drivers and can go into the async_tx tree as it is
> without further dependencies.
> ---
> �drivers/dma/Kconfig � � � �| � �8 +
> �drivers/dma/Makefile � � � | � �1 +
> �drivers/dma/amba-pl08x.c � | 2027 ++++++++++++++++++++++++++++++++++++++++++++
> �include/linux/amba/pl08x.h | �183 ++++
> �4 files changed, 2219 insertions(+), 0 deletions(-)
> �create mode 100644 drivers/dma/amba-pl08x.c
> �create mode 100644 include/linux/amba/pl08x.h
>

Acked-by: Viresh Kumar <viresh.kumar(a)st.com>

regards,
viresh.
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