linux-kernel - Re: [RFC PATCH 0/3] Add support of busfreq

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Message-ID: <56e96a3a-4901-c79c-e91d-6b6a0690e5b7@baylibre.com>
Date:   Fri, 15 Mar 2019 10:31:40 +0100
From:   Alexandre Bailon <abailon@...libre.com>
To:     Aisheng Dong <aisheng.dong@....com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "georgi.djakov@...aro.org" <georgi.djakov@...aro.org>
Cc:     "mturquette@...libre.com" <mturquette@...libre.com>,
        "ptitiano@...libre.com" <ptitiano@...libre.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        Zening Wang <zening.wang@....com>,
        "khilman@...libre.com" <khilman@...libre.com>,
        "ccaione@...libre.com" <ccaione@...libre.com>,
        Jacky Bai <ping.bai@....com>,
        Leonard Crestez <leonard.crestez@....com>,
        dl-linux-imx <linux-imx@....com>,
        Ranjani Vaidyanathan <ranjani.vaidyanathan@....com>
Subject: Re: [RFC PATCH 0/3] Add support of busfreq

Hi Aisheng

On 3/15/19 3:39 AM, Aisheng Dong wrote:
> +Jacky and Leonard, Ranjani
> 
> Hi Alexandre,
> 
>> From: Alexandre Bailon [mailto:abailon@...libre.com]
>>
>> This series implements busfreq, a framework used in MXP's tree to scale the
>> interconnect and dram frequencies.
>> In the vendor tree, device's driver request for a performance level, which is
>> used to scale the frequencies.
>> This series implements it using the interconnect framework.
>> Devices' driver request for bandwidth which is use by busfreq to determine a
>> performance level, and then scale the frequency.
>>
>> Busfreq is quite generic. It could be used for any i.MX SoC.
>> A busfreq platform driver just have to define a list of interconnect nodes, and
>> some OPPs.
>>
> 
> It's really great to see this patch series.
> And it should be the correct direction we're heading to upstream busfreq support.
> 
>> This series is sent as RFC mostly because the current support of i.MX SoC won't
>> benefit of busfreq framework, because the clocks' driver don't support
>> interconnect / dram frequency scaling.
>> As exemple, this series implements busfreq for i.MX8MM whose upstreaming
>> is in progress. Because this relies on ATF to do the frequency scaling, it won't
>> be hard make it work.
>>
> 
> How can I test this patch series?
> Any additional patches you can share with us?
> Or what else we need to do to test it? We can help with it.
Many other patches will be required to test the series.
There are a couple of patches that updates i.MX device drivers to 
request for bandwidth (does similar thing as bus_freq_request and 
bus_freq_release).
In addition, a patch to that allow to scale the DRAM
frequency using CCF is required. I'm still working on this patch. It 
works correctly on 4.14, but since I rebased it on linux-next/master, it 
stopped to work. I'm trying to fix it now.
I will share all this patches ASAP.

Best Regards,
Alexandre
> 
> Regards
> Dong Aisheng
> 
>> As exemple, this series implements busfreq for Alexandre Bailon (3):
>>    drivers: interconnect: Add a driver for i.MX SoC
>>    drivers: interconnect: imx: Add support of i.MX8MM
>>    dt-bindings: interconnect: Document fsl,busfreq-imx8mm bindings
>>
>>   .../bindings/interconnect/imx8mm.txt          |  24 +
>>   drivers/interconnect/Kconfig                  |   1 +
>>   drivers/interconnect/Makefile                 |   1 +
>>   drivers/interconnect/imx/Kconfig              |  17 +
>>   drivers/interconnect/imx/Makefile             |   2 +
>>   drivers/interconnect/imx/busfreq-imx8mm.c     | 132 ++++
>>   drivers/interconnect/imx/busfreq.c            | 570
>> ++++++++++++++++++
>>   drivers/interconnect/imx/busfreq.h            | 123 ++++
>>   include/dt-bindings/interconnect/imx8mm.h     |  37 ++
>>   9 files changed, 907 insertions(+)
>>   create mode 100644
>> Documentation/devicetree/bindings/interconnect/imx8mm.txt
>>   create mode 100644 drivers/interconnect/imx/Kconfig  create mode
>> 100644 drivers/interconnect/imx/Makefile  create mode 100644
>> drivers/interconnect/imx/busfreq-imx8mm.c
>>   create mode 100644 drivers/interconnect/imx/busfreq.c
>>   create mode 100644 drivers/interconnect/imx/busfreq.h
>>   create mode 100644 include/dt-bindings/interconnect/imx8mm.h
>>
>> --
>> 2.19.2