[PATCH v9 3/6] ARM: dts: Exynos: add CPU OPP and regulator supply property
Doug Anderson
dianders at chromium.org
Wed Jul 30 20:53:03 PDT 2014
Thomas,
On Wed, Jul 30, 2014 at 8:21 PM, Thomas Abraham <ta.omasab at gmail.com> wrote:
> Hi Doug,
>
> On Thu, Jul 31, 2014 at 6:07 AM, Doug Anderson <dianders at chromium.org> wrote:
>> Thomas,
>>
>> On Wed, Jul 30, 2014 at 1:07 AM, Thomas Abraham <thomas.ab at samsung.com> wrote:
>>> diff --git a/arch/arm/boot/dts/exynos5250-arndale.dts b/arch/arm/boot/dts/exynos5250-arndale.dts
>>> index d0de1f5..3b12a97 100644
>>> --- a/arch/arm/boot/dts/exynos5250-arndale.dts
>>> +++ b/arch/arm/boot/dts/exynos5250-arndale.dts
>>> @@ -575,3 +575,7 @@
>>> usb-phy = <&usb2_phy>;
>>> };
>>> };
>>> +
>>> +&cpu0 {
>>> + cpu0-supply = <&buck2_reg>;
>>> +};
>>> diff --git a/arch/arm/boot/dts/exynos5250-smdk5250.dts b/arch/arm/boot/dts/exynos5250-smdk5250.dts
>>> index b4b35ad..f07e834 100644
>>> --- a/arch/arm/boot/dts/exynos5250-smdk5250.dts
>>> +++ b/arch/arm/boot/dts/exynos5250-smdk5250.dts
>>> @@ -414,3 +414,7 @@
>>> };
>>> };
>>> };
>>> +
>>> +&cpu0 {
>>> + cpu0-supply = <&buck2_reg>;
>>> +};
>>> diff --git a/arch/arm/boot/dts/exynos5250-snow.dts b/arch/arm/boot/dts/exynos5250-snow.dts
>>> index f2b8c41..91acca7 100644
>>> --- a/arch/arm/boot/dts/exynos5250-snow.dts
>>> +++ b/arch/arm/boot/dts/exynos5250-snow.dts
>>> @@ -509,4 +509,8 @@
>>> };
>>> };
>>>
>>> +&cpu0 {
>>> + cpu0-supply = <&buck2_reg>;
>>> +};
>>> +
>>> #include "cros-ec-keyboard.dtsi"
>>> diff --git a/arch/arm/boot/dts/exynos5250.dtsi b/arch/arm/boot/dts/exynos5250.dtsi
>>> index 492e1ef..97b282c 100644
>>> --- a/arch/arm/boot/dts/exynos5250.dtsi
>>> +++ b/arch/arm/boot/dts/exynos5250.dtsi
>>> @@ -58,11 +58,34 @@
>>> #address-cells = <1>;
>>> #size-cells = <0>;
>>>
>>> - cpu at 0 {
>>> + cpu0: cpu at 0 {
>>> device_type = "cpu";
>>> compatible = "arm,cortex-a15";
>>> reg = <0>;
>>> clock-frequency = <1700000000>;
>>> +
>>> + clocks = <&clock CLK_ARM_CLK>;
>>> + clock-names = "cpu";
>>> + clock-latency = <140000>;
>>
>> Where did the 140000 number come from? My old calculations show that
>> with lock time of 270 ad P up to 6 we were at 67.5us lock time.
>
> I measured the time taken by clk_set_rate call in the cpufreq driver
> using do_gettimeofday(). The time taken to change the clock speed was
> between 87us to 134us for Exynos5420. So I just took the worst case
> time of 140us. Also, the time taken to change the CPU clock speed
> includes the settling time for changes to dividers and mux clock
> blocks.
Interesting. I wonder why the difference between my earlier
calculations. It seems just about double. :-/
>>> + operating-points = <
>>> + 1700000 1300000
>>> + 1600000 1250000
>>> + 1500000 1225000
>>> + 1400000 1200000
>>> + 1300000 1150000
>>> + 1200000 1125000
>>> + 1100000 1100000
>>> + 1000000 1075000
>>> + 900000 1050000
>>> + 800000 1025000
>>> + 700000 1012500
>>> + 600000 1000000
>>> + 500000 975000
>>> + 400000 950000
>>> + 300000 937500
>>> + 200000 925000
>>> + >;
>>> };
>>> cpu at 1 {
>>> device_type = "cpu";
>>> diff --git a/arch/arm/boot/dts/exynos5420.dtsi b/arch/arm/boot/dts/exynos5420.dtsi
>>> index cb2b70e..3154b4c 100644
>>> --- a/arch/arm/boot/dts/exynos5420.dtsi
>>> +++ b/arch/arm/boot/dts/exynos5420.dtsi
>>> @@ -59,8 +59,26 @@
>>> device_type = "cpu";
>>> compatible = "arm,cortex-a15";
>>> reg = <0x0>;
>>> + clocks = <&clock CLK_ARM_CLK>;
>>> + clock-names = "cpu-cluster.0";
>>> clock-frequency = <1800000000>;
>>> cci-control-port = <&cci_control1>;
>>> + clock-latency = <140000>;
>>> +
>>> + operating-points = <
>>> + 1800000 1250000
>>> + 1700000 1212500
>>> + 1600000 1175000
>>> + 1500000 1137500
>>> + 1400000 1112500
>>> + 1300000 1062500
>>> + 1200000 1037500
>>> + 1100000 1012500
>>> + 1000000 987500
>>> + 900000 962500
>>> + 800000 937500
>>> + 700000 912500
>>> + >;
>>> };
>>>
>>> cpu1: cpu at 1 {
>>> @@ -69,6 +87,7 @@
>>> reg = <0x1>;
>>> clock-frequency = <1800000000>;
>>> cci-control-port = <&cci_control1>;
>>> + clock-latency = <140000>;
>>> };
>>>
>>> cpu2: cpu at 2 {
>>> @@ -77,6 +96,7 @@
>>> reg = <0x2>;
>>> clock-frequency = <1800000000>;
>>> cci-control-port = <&cci_control1>;
>>> + clock-latency = <140000>;
>>> };
>>>
>>> cpu3: cpu at 3 {
>>> @@ -85,14 +105,29 @@
>>> reg = <0x3>;
>>> clock-frequency = <1800000000>;
>>> cci-control-port = <&cci_control1>;
>>> + clock-latency = <140000>;
>>> };
>>>
>>> cpu4: cpu at 100 {
>>> device_type = "cpu";
>>> compatible = "arm,cortex-a7";
>>> reg = <0x100>;
>>> + clocks = <&clock CLK_KFC_CLK>;
>>> + clock-names = "cpu-cluster.1";
>>> clock-frequency = <1000000000>;
>>
>> It does't start out at its maximum?
>
> The A7 CPU clock need not start with the maximum. On the SMDK5420
> board, the firmware has set the A7 CPU clock to 1GHz. So I used the
> same value here.
Does it need to match the firmware? On exynos5420-peach-pit and
peach-pi I think the firmware starts the kernel at 1.7GHz.
>>> cci-control-port = <&cci_control0>;
>>> + clock-latency = <140000>;
>>> +
>>> + operating-points = <
>>> + 1300000 1275000
>>> + 1200000 1212500
>>> + 1100000 1162500
>>> + 1000000 1112500
>>> + 900000 1062500
>>> + 800000 1025000
>>> + 700000 975000
>>> + 600000 937500
>>> + >;
>>> };
>>>
>>> cpu5: cpu at 101 {
>>> @@ -101,6 +136,7 @@
>>> reg = <0x101>;
>>> clock-frequency = <1000000000>;
>>> cci-control-port = <&cci_control0>;
>>> + clock-latency = <140000>;
>>> };
>>>
>>> cpu6: cpu at 102 {
>>> @@ -109,6 +145,7 @@
>>> reg = <0x102>;
>>> clock-frequency = <1000000000>;
>>> cci-control-port = <&cci_control0>;
>>> + clock-latency = <140000>;
>>> };
>>>
>>> cpu7: cpu at 103 {
>>> @@ -117,6 +154,7 @@
>>> reg = <0x103>;
>>> clock-frequency = <1000000000>;
>>> cci-control-port = <&cci_control0>;
>>> + clock-latency = <140000>;
>>> };
>>> };
>>
>> Don't you need to put a reference to the supply in the 5420 board
>> files? ...or is that not possible yet since the max77802 hasn't
>> landed yet?
>
> The arm big.little cpufreq driver does not have voltage scaling
> support yet. So the supply was not mentioned.
>
>>
>> If that's not possible, is there any reason to post the 5420.dtsi
>> patch now? Also: what about 5800? It's so similar to 5420 that it
>> seems a shame not to do them at the same time.
>
> This patch series has support for Exynos5800 as well. But it is A15
> clock is restricted to 1.8GHz for now since we do not have a way to
> handle the vdd_arm and vdd_int voltage difference with 1.9GHz and
> 2.0GHZ in upstream yet.
Oh, right! The 5800 includes the 5420 dtsi...
-Doug
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