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Message-ID: <a3179721-3a0e-651b-f422-c08463aae7e6@osg.samsung.com>
Date: Wed, 14 Dec 2016 11:06:45 -0300
From: Javier Martinez Canillas <javier@....samsung.com>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Arjun K V <arjun.kv@...sung.com>
Cc: Krzysztof Kozlowski <krzk@...nel.org>,
Kukjin Kim <kgene@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Russell King <linux@...linux.org.uk>,
Doug Anderson <dianders@...omium.org>,
Andreas Faerber <afaerber@...e.de>,
Thomas Abraham <thomas.ab@...sung.com>,
Ben Gamari <ben@...rt-cactus.org>,
linux-samsung-soc@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
Abhilash Kesavan <a.kesavan@...sung.com>
Subject: Re: [PATCH] ARM: dts: Add missing CPU frequencies for Exynos5422/5800
Hello Bartlomiej,
On 12/14/2016 10:28 AM, Bartlomiej Zolnierkiewicz wrote:
>
> On Tuesday, December 13, 2016 04:18:05 PM Javier Martinez Canillas wrote:
>> Hello Bartlomiej,
>
> Hi,
>
>> On 12/13/2016 01:52 PM, Bartlomiej Zolnierkiewicz wrote:
>>> Add missing 2000MHz & 1900MHz OPPs (for A15 cores) and 1400MHz OPP
>>> (for A7 cores). Also update common Odroid-XU3 Lite/XU3/XU4 thermal
>>> cooling maps to account for new OPPs.
>>>
>>> Since new OPPs are not available on all Exynos5422/5800 boards modify
>>> dts files for Odroid-XU3 Lite (limited to 1.8 GHz / 1.3 GHz) & Peach
>>> Pi (limited to 2.0 GHz / 1.3 GHz) accordingly.
>>>
>>> Tested on Odroid-XU3 and XU3 Lite.
>>>
>>> Cc: Doug Anderson <dianders@...omium.org>
>>> Cc: Javier Martinez Canillas <javier@....samsung.com>
>>> Cc: Andreas Faerber <afaerber@...e.de>
>>> Cc: Thomas Abraham <thomas.ab@...sung.com>
>>> Cc: Ben Gamari <ben@...rt-cactus.org>
>>> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
>>> ---
>>> arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi | 14 +++++++-------
>>> arch/arm/boot/dts/exynos5422-odroidxu3-lite.dts | 17 +++++++++++++++++
>>> arch/arm/boot/dts/exynos5800-peach-pi.dts | 4 ++++
>>> arch/arm/boot/dts/exynos5800.dtsi | 15 +++++++++++++++
>>> 4 files changed, 43 insertions(+), 7 deletions(-)
>>>
>>> Index: b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>>> ===================================================================
>>> --- a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi 2016-12-13 15:59:33.779763261 +0100
>>> +++ b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi 2016-12-13 15:59:33.775763261 +0100
>>> @@ -118,7 +118,7 @@
>>> /*
>>> * When reaching cpu_alert3, reduce CPU
>>> * by 2 steps. On Exynos5422/5800 that would
>>> - * be: 1600 MHz and 1100 MHz.
>>> + * (usually) be: 1800 MHz and 1200 MHz.
>>> */
>>> map3 {
>>> trip = <&cpu_alert3>;
>>> @@ -131,16 +131,16 @@
>>>
>>> /*
>>> * When reaching cpu_alert4, reduce CPU
>>> - * further, down to 600 MHz (11 steps for big,
>>> - * 7 steps for LITTLE).
>>> + * further, down to 600 MHz (13 steps for big,
>>> + * 8 steps for LITTLE).
>>> */
>>> - map5 {
>>> + cooling_map5: map5 {
>>> trip = <&cpu_alert4>;
>>> - cooling-device = <&cpu0 3 7>;
>>> + cooling-device = <&cpu0 3 8>;
>>> };
>>> - map6 {
>>> + cooling_map6: map6 {
>>> trip = <&cpu_alert4>;
>>> - cooling-device = <&cpu4 3 11>;
>>> + cooling-device = <&cpu4 3 13>;
>>> };
>>> };
>>> };
>>> Index: b/arch/arm/boot/dts/exynos5422-odroidxu3-lite.dts
>>> ===================================================================
>>> --- a/arch/arm/boot/dts/exynos5422-odroidxu3-lite.dts 2016-12-13 15:59:33.779763261 +0100
>>> +++ b/arch/arm/boot/dts/exynos5422-odroidxu3-lite.dts 2016-12-13 15:59:33.775763261 +0100
>>> @@ -21,6 +21,23 @@
>>> compatible = "hardkernel,odroid-xu3-lite", "samsung,exynos5800", "samsung,exynos5";
>>> };
>>>
>>> +&cluster_a15_opp_table {
>>> + /delete-node/opp@...0000000;
>>> + /delete-node/opp@...0000000;
>>> +};
>>> +
>>> +&cluster_a7_opp_table {
>>> + /delete-node/opp@...0000000;
>>> +};
>>> +
>>
>> I think that a comment in the DTS why these operating points aren't available
>> in this board will make more clear why the nodes are being deleted.
>
> Ok, I will add these comments in the next patch revision.
>
>>> +&cooling_map5 {
>>> + cooling-device = <&cpu0 3 7>;
>>> +};
>>> +
>>> +&cooling_map6 {
>>> + cooling-device = <&cpu4 3 11>;
>>> +};
>>> +
>>> &pwm {
>>> /*
>>> * PWM 0 -- fan
>>> Index: b/arch/arm/boot/dts/exynos5800-peach-pi.dts
>>> ===================================================================
>>> --- a/arch/arm/boot/dts/exynos5800-peach-pi.dts 2016-12-13 15:59:33.779763261 +0100
>>> +++ b/arch/arm/boot/dts/exynos5800-peach-pi.dts 2016-12-13 15:59:33.779763261 +0100
>>> @@ -146,6 +146,10 @@
>>> vdd-supply = <&ldo9_reg>;
>>> };
>>>
>>> +&cluster_a7_opp_table {
>>> + /delete-property/opp@...0000000;
>>> +};
>>> +
>>> &cpu0 {
>>> cpu-supply = <&buck2_reg>;
>>> };
>>> Index: b/arch/arm/boot/dts/exynos5800.dtsi
>>> ===================================================================
>>> --- a/arch/arm/boot/dts/exynos5800.dtsi 2016-12-13 15:59:33.779763261 +0100
>>> +++ b/arch/arm/boot/dts/exynos5800.dtsi 2016-12-13 15:59:33.779763261 +0100
>>> @@ -24,6 +24,16 @@
>>> };
>>>
>>> &cluster_a15_opp_table {
>>> + opp@...0000000 {
>>> + opp-hz = /bits/ 64 <2000000000>;
>>> + opp-microvolt = <1250000>;
>>> + clock-latency-ns = <140000>;
>>> + };
>>> + opp@...0000000 {
>>> + opp-hz = /bits/ 64 <1900000000>;
>>> + opp-microvolt = <1250000>;
>>> + clock-latency-ns = <140000>;
>>> + };
>>> opp@...0000000 {
>>> opp-microvolt = <1250000>;
>>> };
>>> @@ -85,6 +95,11 @@
>>> };
>>>
>>
>> AFAIK Thomas restricted the maximum OPP, because for A15 freqs > 1.8GHz the
>> INT rail would need to be scaled up as well since there's a maximum voltage
>> difference between the ARM and INT rails before the system becomes unstable:
>>
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-July/276766.html
>> https://lkml.org/lkml/2014/5/2/419
>>
>> The ChromiumOS vendor tree uses a virtual regulator driver that makes sure
>> the maximum voltage skew is between a limit. But that never made to mainline:
>>
>> https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-3.8/arch/arm/boot/dts/exynos5420-peach-pit.dtsi#90
>> https://lkml.org/lkml/2014/4/29/28
>>
>> Did that change and there's infrastructure in mainline now to cope with that?
>> If that's the case, I think it would be good to mention in the commit message.
>
> I was not aware of this limitation and AFAIK mainline has currently
> no code to handle it. I also cannot find any code to handle this in
Yes, that's what I thought as well but maybe I was missing something.
> Hardkernel's vendor kernel for Odroid-XU3 board.
>
> Do you know whether this problem exists also on Exynos5422/5800
> SoCs or only on Exynos5420 one? I see that ChromiumOS uses virtual
> regulator code also on Exynos5800 SoC based Peach Pi board but was
> the problem actually present on this board?
>
My understanding is that this problem is present in 5420/5422/5800
but I have no way to confirm this. I'm just guessing from the info
in the ChromiumOS vendor tree.
If you look at the commit that added the regulator-locker driver,
the test says to be done in a Peach Pi so it seems the problem is
not restricted to only Exynos5420:
https://chromium.googlesource.com/chromiumos/third_party/kernel/+/ba63620feace4eaed5572ac2e77d8d61754af704
> [ I added Arjun to Cc:, maybe he can help in explaining this issue
> (unfortunately Inderpal's email is no longer working). ]
>
Added Abhilash to cc list as well since he was involved in the Exynos ChromeOS tree.
> Please also note that on Exynos5422/5800 SoCs the same ARM rail
> voltage is used for 1.9 GHz & 2.0 GHz OPPs as for the 1.8 GHz one.
> IOW if the problem exists it is already present in the mainline
> kernel.
>
Ah, I only looked at your patch and I didn't compare the voltage levels
in your 1.9 GHz and 2.0 GHz OPPs with the current 1.8 GHz in mainline.
I wonder if the voltage levels in your patch are correct then, since the
ChromiumOS tree uses a higher voltages for the 1.9 GHz and 2.0 GHz OPPs:
/*
* Default ASV table
*/
static const unsigned int asv_voltage_5420[CPUFREQ_NUM_LEVELS] = {
1362500, /* L0 2100 */
1312500, /* L1 2000 */
1275000, /* L2 1900 */
1225000, /* L3 1800 */
1200000, /* L4 1700 */
This is from https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-3.8/drivers/cpufreq/exynos5420-cpufreq.c#175
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
>
Best regards,
--
Javier Martinez Canillas
Open Source Group
Samsung Research America
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