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

[Santosh Shilimkar <santosh.shilimkar-l0cyMroinI0@public.gmane.org>]

On Thursday 01 May 2014 09:25 AM, Russell King - ARM Linux 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-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
>>> Cc: Russell King <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>
>>> Cc: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
>>> Cc: Olof Johansson <olof-nZhT3qVonbNeoWH0uzbU5w@public.gmane.org>
>>> Cc: Grant Likely <grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>>> Cc: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
>>> Cc: Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>
>>> Cc: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>>> Cc: Grygorii Strashko <grygorii.strashko-l0cyMroinI0@public.gmane.org>
>>>
>>> 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.
> 
> 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.
> 
I really hope we don't have to go this route. I think since the changes
as such used for ARM arch for now, if we get this series via your tree
or arm-soc which pulls your tree, things should work. I also have small
series on the list on top of $subject series which enables coherency
for Keystone.

Regards,
Santosh


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