From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Sinan Kaya <okaya@codeaurora.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
dmaengine <dmaengine@vger.kernel.org>,
timur@codeaurora.org, cov@codeaurora.org, jcm@redhat.com,
Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
Vinod Koul <vinod.koul@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
devicetree <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver
Date: Fri, 30 Oct 2015 20:18:49 +0200 [thread overview]
Message-ID: <CAHp75Ve_7NeyJD==EpgzKes9n9wb5oTwtNt7FvZHUSUxqZ4+=Q@mail.gmail.com> (raw)
In-Reply-To: <5633B207.5030505@codeaurora.org>
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
next prev parent reply other threads:[~2015-10-30 18:18 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-30 3:08 [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Sinan Kaya
2015-10-30 3:08 ` [PATCH 2/2] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya
2015-10-30 8:01 ` kbuild test robot
2015-10-30 8:07 ` kbuild test robot
2015-10-30 10:24 ` Arnd Bergmann
2015-10-30 21:42 ` Sinan Kaya
2015-10-30 21:55 ` Timur Tabi
2015-10-30 22:47 ` Arnd Bergmann
2015-10-30 22:28 ` Arnd Bergmann
2015-10-30 22:36 ` Timur Tabi
2015-10-30 22:50 ` Arnd Bergmann
2015-10-31 1:53 ` Sinan Kaya
2015-11-01 18:50 ` Sinan Kaya
2015-11-01 20:21 ` Timur Tabi
2015-11-01 20:27 ` Sinan Kaya
2015-11-02 16:33 ` Arnd Bergmann
2015-11-02 19:21 ` Sinan Kaya
2015-11-02 20:55 ` Arnd Bergmann
2015-11-03 5:29 ` Sinan Kaya
2015-11-03 10:43 ` Arnd Bergmann
2015-11-03 21:07 ` Sinan Kaya
2015-11-03 21:10 ` Arnd Bergmann
2015-10-30 14:50 ` Mark Rutland
2015-10-31 4:27 ` Sinan Kaya
2015-10-30 4:34 ` [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver kbuild test robot
2015-10-30 4:34 ` [PATCH] dma: fix platform_no_drv_owner.cocci warnings kbuild test robot
2015-10-30 9:34 ` [PATCH 1/2] dma: add Qualcomm Technologies HIDMA management driver Arnd Bergmann
2015-10-31 6:51 ` Sinan Kaya
2015-10-31 12:53 ` Timur Tabi
2015-10-31 12:53 ` Timur Tabi
2015-11-02 21:30 ` Arnd Bergmann
2015-11-03 4:45 ` Sinan Kaya
2015-11-03 12:42 ` Arnd Bergmann
2015-11-03 14:26 ` Timur Tabi
2015-11-04 1:04 ` Sinan Kaya
2015-10-30 15:00 ` Mark Rutland
2015-10-30 17:59 ` Andy Shevchenko
2015-10-30 18:08 ` Sinan Kaya
2015-10-30 18:18 ` Mark Rutland
2015-10-30 18:18 ` Andy Shevchenko [this message]
2015-10-30 18:25 ` Mark Rutland
2015-10-30 18:40 ` Andy Shevchenko
2015-10-30 18:48 ` Sinan Kaya
2015-10-30 19:01 ` Mark Rutland
2015-10-30 20:08 ` Al Stone
2015-10-30 20:15 ` Andy Shevchenko
2015-10-30 20:18 ` Mark Rutland
2015-10-31 3:33 ` Jon Masters
2015-10-31 17:34 ` Sinan Kaya
2015-10-30 19:36 ` Sinan Kaya
2015-10-31 17:11 ` Sinan Kaya
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