Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver

From	Andy Shevchenko <andy.shevchenko@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver
Date	2015-10-30 19:20 +0100
Message-ID	<qpmro-HX-11@gated-at.bofh.it> (permalink)
References	<qp8eK-oK-5@gated-at.bofh.it> <qpjtw-7np-25@gated-at.bofh.it> <qpmhI-Ey-7@gated-at.bofh.it> <qpmhJ-Ey-25@gated-at.bofh.it>
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On Fri, Oct 30, 2015 at 8:08 PM, Sinan Kaya <okaya@codeaurora.org> wrote:

>> The ACPI tables DSDT and CSRT (more info here:
>> http://www.acpi.info/links.htm) defines properties.
>>
>> DSDT:
>>   per DMAC: the resources
>>   per client: FixedDMA descriptor that contains channel / request line
>> pair.
>>
>> CSRT:
>>   necessary table to map which DMAC provides which request line, thus
>> request line numbering are global on platform.
>>
>> When DMAC driver is probed in the running system it should call as
>> well registration function from acpi-dma.c.
>>
>> All clients when use new DMA slave API gets channel automatically
>> based on their FixedDMA property.
>>
>> So, above is how it should be done. Didn't actually checked what this
>> driver does.
>>
> I was going to reply to all the questions in one pass but let me handle
> piece by piece.
>
> Here are some facts.
> - This hardware supports memcpy and memset only.
> - Memset feature was removed from the kernel sometime around 3.14. So no
> memset support in this driver either.
> - The hardware does not support DMA slave support
> - The goal is to provide an interface to DMA engine framework for memcpy
> optimization so that the rest of the kernel drivers and applications make
> use of the hardware.
>

> CSRT is an Intel specific ACPI table for slave devices.

Wrong.
It was designed by Microsoft to support multiple controllers, in
particular DMACs.
Have you read that document I posted link to?

> It was decided by
> Linaro that CSRT will not be supported for ARM64.

Interesting, ARM64 platforms are not going to have more than one DMAC
per system?

> There were some discussions in ACPI forums to define a similar table for
> ARM64 but we are not there today and this hardware does not support slave
> interface.
>
> ACPI enumeration is just like any other platform device. The driver gets
> looked up by a QCOM specific HID and the driver gets probed with the rest of
> the arguments in DSM object similar to device-tree attributes. The code uses
> device functions so the driver is not aware of where the parameters are
> coming from.



-- 
With Best Regards,
Andy Shevchenko
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Thread

[PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-30 04:10 +0100
  Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver kbuild test robot <lkp@intel.com> - 2015-10-30 05:40 +0100
  [PATCH] dma: fix platform_no_drv_owner.cocci warnings kbuild test robot <lkp@intel.com> - 2015-10-30 05:40 +0100
  Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Arnd Bergmann <arnd@arndb.de> - 2015-10-30 10:40 +0100
    Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-31 08:00 +0100
      Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Timur Tabi <timur@codeaurora.org> - 2015-10-31 14:00 +0100
      Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Timur Tabi <timur@codeaurora.org> - 2015-10-31 14:00 +0100
      Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Arnd Bergmann <arnd@arndb.de> - 2015-11-02 22:40 +0100
        Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Sinan Kaya <okaya@codeaurora.org> - 2015-11-03 05:50 +0100
          Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Arnd Bergmann <arnd@arndb.de> - 2015-11-03 13:50 +0100
            Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Timur Tabi <timur@codeaurora.org> - 2015-11-03 15:30 +0100
            Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Sinan Kaya <okaya@codeaurora.org> - 2015-11-04 02:10 +0100
  Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Arnd Bergmann <arnd@arndb.de> - 2015-10-30 11:30 +0100
    Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-30 22:50 +0100
      Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Timur Tabi <timur@codeaurora.org> - 2015-10-30 23:00 +0100
        Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Arnd Bergmann <arnd@arndb.de> - 2015-10-30 23:50 +0100
      Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Timur Tabi <timur@codeaurora.org> - 2015-10-30 23:40 +0100
        Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Arnd Bergmann <arnd@arndb.de> - 2015-10-31 00:00 +0100
      Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Arnd Bergmann <arnd@arndb.de> - 2015-10-30 23:40 +0100
        Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-31 03:00 +0100
        Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya <okaya@codeaurora.org> - 2015-11-01 20:00 +0100
          Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Timur Tabi <timur@codeaurora.org> - 2015-11-01 21:30 +0100
            Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya <okaya@codeaurora.org> - 2015-11-01 21:30 +0100
          Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Arnd Bergmann <arnd@arndb.de> - 2015-11-02 17:40 +0100
            Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya <okaya@codeaurora.org> - 2015-11-02 20:30 +0100
              Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Arnd Bergmann <arnd@arndb.de> - 2015-11-02 22:00 +0100
                Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya <okaya@codeaurora.org> - 2015-11-03 06:30 +0100
                Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Arnd Bergmann <arnd@arndb.de> - 2015-11-03 11:50 +0100
                Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya <okaya@codeaurora.org> - 2015-11-03 22:10 +0100
                Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Arnd Bergmann <arnd@arndb.de> - 2015-11-03 22:20 +0100
  Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Mark Rutland <mark.rutland@arm.com> - 2015-10-30 16:00 +0100
    Re: [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-31 05:30 +0100
  Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Mark Rutland <mark.rutland@arm.com> - 2015-10-30 16:10 +0100
    Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Andy Shevchenko <andy.shevchenko@gmail.com> - 2015-10-30 19:10 +0100
      Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-30 19:10 +0100
        Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Mark Rutland <mark.rutland@arm.com> - 2015-10-30 19:20 +0100
        Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Andy Shevchenko <andy.shevchenko@gmail.com> - 2015-10-30 19:20 +0100
          Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Mark Rutland <mark.rutland@arm.com> - 2015-10-30 19:30 +0100
            Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Andy Shevchenko <andy.shevchenko@gmail.com> - 2015-10-30 19:50 +0100
              Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-30 19:50 +0100
                Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Mark Rutland <mark.rutland@arm.com> - 2015-10-30 20:10 +0100
                Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Al Stone <al.stone@linaro.org> - 2015-10-30 21:10 +0100
                Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Mark Rutland <mark.rutland@arm.com> - 2015-10-30 21:20 +0100
                Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Andy Shevchenko <andy.shevchenko@gmail.com> - 2015-10-30 21:20 +0100
                Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Jon Masters <jcm@redhat.com> - 2015-10-31 04:40 +0100
                Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-31 18:40 +0100
            Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-30 20:40 +0100
    Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management  driver Sinan Kaya <okaya@codeaurora.org> - 2015-10-31 18:20 +0100

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