Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCHv1 0/3] Odroid c2 missing regulator linking
To:     Anand Moon <linux.amoon@gmail.com>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Jerome Brunet <jbrunet@baylibre.com>,
        Kevin Hilman <khilman@baylibre.com>,
        devicetree <devicetree@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        linux-amlogic@lists.infradead.org,
        Linux Kernel <linux-kernel@vger.kernel.org>
References: <20190828202723.1145-1-linux.amoon@gmail.com>
 <8c40f334-c723-b524-857c-73734b7d0827@baylibre.com>
 <CANAwSgShr-K-44UzdxFC7pvpTye_pbEMdS6ug1eWwYhnsVNGdQ@mail.gmail.com>
 <101a12ac-1464-8864-4f8c-56bb46034a08@baylibre.com>
 <CANAwSgQwZg_AXAnAY4KwDzHpwcSA9up7SrR6jyv5Bem24wtaJg@mail.gmail.com>
From:   Neil Armstrong <narmstrong@baylibre.com>
Openpgp: preference=signencrypt
Autocrypt: addr=narmstrong@baylibre.com; prefer-encrypt=mutual; keydata=
 mQENBE1ZBs8BCAD78xVLsXPwV/2qQx2FaO/7mhWL0Qodw8UcQJnkrWmgTFRobtTWxuRx8WWP
 GTjuhvbleoQ5Cxjr+v+1ARGCH46MxFP5DwauzPekwJUD5QKZlaw/bURTLmS2id5wWi3lqVH4
 BVF2WzvGyyeV1o4RTCYDnZ9VLLylJ9bneEaIs/7cjCEbipGGFlfIML3sfqnIvMAxIMZrvcl9
 qPV2k+KQ7q+aXavU5W+yLNn7QtXUB530Zlk/d2ETgzQ5FLYYnUDAaRl+8JUTjc0CNOTpCeik
 80TZcE6f8M76Xa6yU8VcNko94Ck7iB4vj70q76P/J7kt98hklrr85/3NU3oti3nrIHmHABEB
 AAG0KE5laWwgQXJtc3Ryb25nIDxuYXJtc3Ryb25nQGJheWxpYnJlLmNvbT6JATsEEwEKACUC
 GyMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheABQJXDO2CAhkBAAoJEBaat7Gkz/iubGIH/iyk
 RqvgB62oKOFlgOTYCMkYpm2aAOZZLf6VKHKc7DoVwuUkjHfIRXdslbrxi4pk5VKU6ZP9AKsN
 NtMZntB8WrBTtkAZfZbTF7850uwd3eU5cN/7N1Q6g0JQihE7w4GlIkEpQ8vwSg5W7hkx3yQ6
 2YzrUZh/b7QThXbNZ7xOeSEms014QXazx8+txR7jrGF3dYxBsCkotO/8DNtZ1R+aUvRfpKg5
 ZgABTC0LmAQnuUUf2PHcKFAHZo5KrdO+tyfL+LgTUXIXkK+tenkLsAJ0cagz1EZ5gntuheLD
 YJuzS4zN+1Asmb9kVKxhjSQOcIh6g2tw7vaYJgL/OzJtZi6JlIW5AQ0ETVkGzwEIALyKDN/O
 GURaHBVzwjgYq+ZtifvekdrSNl8TIDH8g1xicBYpQTbPn6bbSZbdvfeQPNCcD4/EhXZuhQXM
 coJsQQQnO4vwVULmPGgtGf8PVc7dxKOeta+qUh6+SRh3vIcAUFHDT3f/Zdspz+e2E0hPV2hi
 SvICLk11qO6cyJE13zeNFoeY3ggrKY+IzbFomIZY4yG6xI99NIPEVE9lNBXBKIlewIyVlkOa
 YvJWSV+p5gdJXOvScNN1epm5YHmf9aE2ZjnqZGoMMtsyw18YoX9BqMFInxqYQQ3j/HpVgTSv
 mo5ea5qQDDUaCsaTf8UeDcwYOtgI8iL4oHcsGtUXoUk33HEAEQEAAYkBHwQYAQIACQUCTVkG
 zwIbDAAKCRAWmrexpM/4rrXiB/sGbkQ6itMrAIfnM7IbRuiSZS1unlySUVYu3SD6YBYnNi3G
 5EpbwfBNuT3H8//rVvtOFK4OD8cRYkxXRQmTvqa33eDIHu/zr1HMKErm+2SD6PO9umRef8V8
 2o2oaCLvf4WeIssFjwB0b6a12opuRP7yo3E3gTCSKmbUuLv1CtxKQF+fUV1cVaTPMyT25Od+
 RC1K+iOR0F54oUJvJeq7fUzbn/KdlhA8XPGzwGRy4zcsPWvwnXgfe5tk680fEKZVwOZKIEuJ
 C3v+/yZpQzDvGYJvbyix0lHnrCzq43WefRHI5XTTQbM0WUIBIcGmq38+OgUsMYu4NzLu7uZF
 Acmp6h8guQINBFYnf6QBEADQ+wBYa+X2n/xIQz/RUoGHf84Jm+yTqRT43t7sO48/cBW9vAn9
 GNwnJ3HRJWKATW0ZXrCr40ES/JqM1fUTfiFDB3VMdWpEfwOAT1zXS+0rX8yljgsWR1UvqyEP
 3xN0M/40Zk+rdmZKaZS8VQaXbveaiWMEmY7sBV3QvgOzB7UF2It1HwoCon5Y+PvyE3CguhBd
 9iq5iEampkMIkbA3FFCpQFI5Ai3BywkLzbA3ZtnMXR8Qt9gFZtyXvFQrB+/6hDzEPnBGZOOx
 zkd/iIX59SxBuS38LMlhPPycbFNmtauOC0DNpXCv9ACgC9tFw3exER/xQgSpDVc4vrL2Cacr
 wmQp1k9E0W+9pk/l8S1jcHx03hgCxPtQLOIyEu9iIJb27TjcXNjiInd7Uea195NldIrndD+x
 58/yU3X70qVY+eWbqzpdlwF1KRm6uV0ZOQhEhbi0FfKKgsYFgBIBchGqSOBsCbL35f9hK/JC
 6LnGDtSHeJs+jd9/qJj4WqF3x8i0sncQ/gszSajdhnWrxraG3b7/9ldMLpKo/OoihfLaCxtv
 xYmtw8TGhlMaiOxjDrohmY1z7f3rf6njskoIXUO0nabun1nPAiV1dpjleg60s3OmVQeEpr3a
 K7gR1ljkemJzM9NUoRROPaT7nMlNYQL+IwuthJd6XQqwzp1jRTGG26J97wARAQABiQM+BBgB
 AgAJBQJWJ3+kAhsCAikJEBaat7Gkz/iuwV0gBBkBAgAGBQJWJ3+kAAoJEHfc29rIyEnRk6MQ
 AJDo0nxsadLpYB26FALZsWlN74rnFXth5dQVQ7SkipmyFWZhFL8fQ9OiIoxWhM6rSg9+C1w+
 n45eByMg2b8H3mmQmyWztdI95OxSREKwbaXVapCcZnv52JRjlc3DoiiHqTZML5x1Z7lQ1T3F
 8o9sKrbFO1WQw1+Nc91+MU0MGN0jtfZ0Tvn/ouEZrSXCE4K3oDGtj3AdC764yZVq6CPigCgs
 6Ex80k6QlzCdVP3RKsnPO2xQXXPgyJPJlpD8bHHHW7OLfoR9DaBNympfcbQJeekQrTvyoASw
 EOTPKE6CVWrcQIztUp0WFTdRGgMK0cZB3Xfe6sOp24PQTHAKGtjTHNP/THomkH24Fum9K3iM
 /4Wh4V2eqGEgpdeSp5K+LdaNyNgaqzMOtt4HYk86LYLSHfFXywdlbGrY9+TqiJ+ZVW4trmui
 NIJCOku8SYansq34QzYM0x3UFRwff+45zNBEVzctSnremg1mVgrzOfXU8rt+4N1b2MxorPF8
 619aCwVP7U16qNSBaqiAJr4e5SNEnoAq18+1Gp8QsFG0ARY8xp+qaKBByWES7lRi3QbqAKZf
 yOHS6gmYo9gBmuAhc65/VtHMJtxwjpUeN4Bcs9HUpDMDVHdfeRa73wM+wY5potfQ5zkSp0Jp
 bxnv/cRBH6+c43stTffprd//4Hgz+nJcCgZKtCYIAPkUxABC85ID2CidzbraErVACmRoizhT
 KR2OiqSLW2x4xdmSiFNcIWkWJB6Qdri0Fzs2dHe8etD1HYaht1ZhZ810s7QOL7JwypO8dscN
 KTEkyoTGn6cWj0CX+PeP4xp8AR8ot4d0BhtUY34UPzjE1/xyrQFAdnLd0PP4wXxdIUuRs0+n
 WLY9Aou/vC1LAdlaGsoTVzJ2gX4fkKQIWhX0WVk41BSFeDKQ3RQ2pnuzwedLO94Bf6X0G48O
 VsbXrP9BZ6snXyHfebPnno/te5XRqZTL9aJOytB/1iUna+1MAwBxGFPvqeEUUyT+gx1l3Acl
 ZaTUOEkgIor5losDrePdPgE=
Organization: Baylibre
Message-ID: <c25c6610-5393-ef9d-8a91-6fad088ac2c2@baylibre.com>
Date:   Fri, 30 Aug 2019 11:50:01 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.8.0
MIME-Version: 1.0
In-Reply-To: <CANAwSgQwZg_AXAnAY4KwDzHpwcSA9up7SrR6jyv5Bem24wtaJg@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 30/08/2019 11:34, Anand Moon wrote:
> Hi Neil,
> 
> On Fri, 30 Aug 2019 at 13:01, Neil Armstrong <narmstrong@baylibre.com> wrote:
>>
>> On 29/08/2019 20:35, Anand Moon wrote:
>>> Hi Neil,
>>>
>>> On Thu, 29 Aug 2019 at 13:58, Neil Armstrong <narmstrong@baylibre.com> wrote:
>>>>
>>>> On 28/08/2019 22:27, Anand Moon wrote:
>>>>> Below small changes help re-configure or fix missing inter linking
>>>>> of regulator node.
>>>>>
>>>>> Changes based top on my prevoius series.
>>>>
>>>> For the serie:
>>>> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
>>>>
>>>
>>> Thanks for your review.
>>>
>>>>>
>>>>> [0] https://patchwork.kernel.org/cover/11113091/
>>>>>
>>>>> TOOD: Add support for DVFS GXBB odroid board in next series.
>>>>
>>>> I'm curious how you will do this !
>>>
>>> I was just studying you previous series on how you have implemented
>>> this feature for C1, N2 and VIM3 boards.
>>>
>>> [0] https://patchwork.kernel.org/cover/11114125/
>>>
>>> I started gathering key inputs needed for this ie *clk / pwm*
>>> like VDDCPU and VDDE clk changes.
>>>
>>> But it looks like of the complex clk framework needed, so I leave this to the
>>> expert like your team of developers to do this much quick and efficiently.
>>
>> On GXBB, GXL, GXM and AXG SoCs, CPU Frequency setting and PWM Regulator setup is
>> done by the SCPI Co-processor via the SCPI protocol.
>>
>> Thus, we should not handle it from Linux, and even if we could, we don't have the
>> registers documentation of the CPU clusters clock tree.
>>
> 
> Ok thanks.
> 
>> SCPI works fine on all tested devices, except Odroid-C2, because Hardkernel left
>> the > 1.5GHz freq in the initial SCPI tables loaded by the BL2, i.e. packed with U-Boot.
>> Nowadays they have removed the bad frequencies, but still some devices uses the old
>> bootloader.
>>
>> But in the SCPI case we trust the table returned by the firmware and use it as-in,
>> and there is no (simple ?) way to override the table and set a max frequency.
>>
>> This is why we disabled SCPI.
>>
>> See https://patchwork.kernel.org/patch/9500175/
> 
> I have quickly enable this on my board and here the cpufreq info
> 
> [alarm@alarm ~]$  cpupower frequency-info
> analyzing CPU 0:
>   driver: scpi-cpufreq
>   CPUs which run at the same hardware frequency: 0 1 2 3
>   CPUs which need to have their frequency coordinated by software: 0 1 2 3
>   maximum transition latency: 200 us
>   hardware limits: 100.0 MHz - 1.54 GHz
>   available frequency steps:  100.0 MHz, 250 MHz, 500 MHz, 1000 MHz,
> 1.30 GHz, 1.54 GHz
>   available cpufreq governors: conservative ondemand userspace
> powersave performance schedutil
>   current policy: frequency should be within 100.0 MHz and 1.54 GHz.
>                   The governor "ondemand" may decide which speed to use
>                   within this range.
>   current CPU frequency: Unable to call hardware
>   current CPU frequency: 250 MHz (asserted by call to kernel)
> 
> I did some simple stress testing and observed the freq scaling is
> working fine when cpufreq governor is set to ondemand.
> 
> Powertop output.
>             Package |            CPU 0
>  100 MHz     5.2%   |  100 MHz     1.6%
>  250 MHz     4.4%   |  250 MHz     4.3%
>  500 MHz     2.6%   |  500 MHz     2.4%
> 1000 MHz     0.5%   | 1000 MHz     0.3%
> 1296 MHz     0.2%   | 1296 MHz     0.1%
> 1.54 GHz     0.2%   | 1.54 GHz     0.1%
> Idle        86.9%   | Idle        91.2%
> 
> Here the output on the linaro's pm-qa testing for cpufreq.
> 
> [1] https://pastebin.com/h880WATn
> Almost all the test case pass with this one as off now.

Thanks for passing the tests, no doubt it works with a recent
bootloader binary, but we can't leave alone the first Odroid-C2
devices loaded with an incorrect SCPI table.

I'll let Kevin decide for the following.

Neil

> 
> Best Regards
> -Anand
>