Re: [PATCH v3 0/7] of: setup dma parameters using dma-ranges and dma-coherent

Rob Herring
2014-05-02T14:41:51Z

On Thu, May 1, 2014 at 8:25 AM, Russell King - ARM Linux
<linux@arm.linux.org.uk> wrote:
> On Thu, May 01, 2014 at 09:19:18AM -0400, Santosh Shilimkar wrote:
>> Rob, Russell,
>>
>> On Thursday 24 April 2014 11:30 AM, Santosh Shilimkar wrote:
>> > Here is an updated v3 of the series. Series introduces support for setting up
>> > dma parameters based on device tree properties like 'dma-ranges' and
>> > 'dma-coherent' and also update to ARM 32 bit port. Earlier version of the
>> > series can be found here [3], [2] and [1].
>> >
>> > The 'dma-ranges' helps to take care of few DMAable system memory restrictions
>> > by use of dma_pfn_offset which we maintain now per device. Arch code then
>> > uses it for dma address translations for such cases. We update the
>> > dma_pfn_offset accordingly during DT the device creation process.The
>> > 'dma-coherent' property is used to setup arch's coherent dma_ops.
>> >
>> > Hopefully with acks, tested-by this version can get into 3.16 queue. I will
>> > post a followup series for Keystone SOC which will use this infrastructure.
>> > Linus W also wants to use this for ARM integrator platform dma offset issue.
>> >
>> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> > Cc: Russell King <linux@arm.linux.org.uk>
>> > Cc: Arnd Bergmann <arnd@arndb.de>
>> > Cc: Olof Johansson <olof@lixom.net>
>> > Cc: Grant Likely <grant.likely@linaro.org>
>> > Cc: Rob Herring <robh+dt@kernel.org>
>> > Cc: Catalin Marinas <catalin.marinas@arm.com>
>> > Cc: Linus Walleij <linus.walleij@linaro.org>
>> > Cc: Grygorii Strashko <grygorii.strashko@ti.com>
>> >
>> > Grygorii Strashko (2):
>> > of: introduce of_dma_get_range() helper
>> > ARM: dma: Use dma_pfn_offset for dma address translation
>> >
>> > Santosh Shilimkar (5):
>> > device: introduce per device dma_pfn_offset
>> > of: introduce of_dma_is_coherent() helper
>> > of: configure the platform device dma parameters
>> > ARM: dma: implement set_arch_dma_coherent_ops()
>> > ARM: dma: use phys_addr_t in __dma_page_[cpu_to_dev/dev_to_cpu]
>> >
>> > arch/arm/include/asm/dma-mapping.h | 28 ++++++++++--
>> > arch/arm/mm/dma-mapping.c | 4 +-
>> > drivers/of/address.c | 87 ++++++++++++++++++++++++++++++++++++
>> > drivers/of/platform.c | 71 +++++++++++++++++++++++++++--
>> > include/linux/device.h | 2 +
>> > include/linux/dma-mapping.h | 7 +++
>> > include/linux/of_address.h | 8 ++++
>> > include/linux/of_platform.h | 6 +++
>> > 8 files changed, 204 insertions(+), 9 deletions(-)
>> >
>> How do we go about merging this series ? There is a dependency
>> between the patches and hence the question.
>
> I don't know anymore. People today want to assert exclusive rights over
> parts of the kernel tree, which makes this kind of cross-patching rather
> impossible.

I can take this series or provide an ack for the DT parts. Either way
it does not matter to me.

> The only workable solution I can see is the long winded way to split the
> series up, merge the first set of dependencies in one merge window, and
> hold the rest back for the following merge window. Not ideal, but it
> stops the arguments.

That should not be necessary. We should be able to sort this out as it
is not a difficult problem.

Rob