[PATCH 0/6] Allwinner A33 CPU frequency scaling support

[PATCH 0/6] Allwinner A33 CPU frequency scaling support

[Icenowy Zheng]

This series of patch adds frequency scaling support to Allwinner A33 SoC.

The first two patches fixes some bugs in the A33 CCU code.

The patch 3 and 4 is for enabling the cpufreq-dt driver to work.

The patch 5 is for enabling the voltage adjusting on reference design tablets.

The patch 6 is for enabling the "turbo-mode" of A33. (According to the
"extremity_freq" property in the FEX file. When I tested it with 3.4 BSP, it
really performs as a turbo mode.)

If there's any doubt of safety, the patch 6 can be ignored.

If there's any problem in patch 3, 4 and 5, they can also be temporarily
ignored, but finally we need them ;-)

Although there's now currently no thermal support for A33, many A33 devices
are tablets with battery, and it will be valuable to save some power energy,
so cpufreq support is also useful.

P.S.

Chen-Yu,

Do you want to test the CCU fix and the operating point table on A23?

Regards,
Icenowy

[PATCH 1/6] clk: sunxi-ng: fix PLL_CPUX adjusting on A33

[Icenowy Zheng]

When adjusting PLL_CPUX on A33, the PLL is temporarily driven too high,
and the system hangs.

Add a notifier to avoid this situation by temporarily switching to a
known stable 24 MHz oscillator.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
---
 drivers/clk/sunxi-ng/ccu-sun8i-a33.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
index 3cd4190ccd59..0f3e7d2dc19a 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
@@ -752,6 +752,13 @@ static const struct sunxi_ccu_desc sun8i_a33_ccu_desc = {
 	.num_resets	= ARRAY_SIZE(sun8i_a33_ccu_resets),
 };
 
+static struct ccu_mux_nb sun8i_a33_cpu_nb = {
+	.common		= &cpux_clk.common,
+	.cm		= &cpux_clk.mux,
+	.delay_us	= 1, /* > 8 clock cycles at 24 MHz */
+	.bypass_index	= 1, /* index of 24 MHz oscillator */
+};
+
 static void __init sun8i_a33_ccu_setup(struct device_node *node)
 {
 	void __iomem *reg;
@@ -775,6 +782,9 @@ static void __init sun8i_a33_ccu_setup(struct device_node *node)
 	writel(val, reg + SUN8I_A33_PLL_MIPI_REG);
 
 	sunxi_ccu_probe(node, reg, &sun8i_a33_ccu_desc);
+
+	ccu_mux_notifier_register(pll_cpux_clk.common.hw.clk,
+				  &sun8i_a33_cpu_nb);
 }
 CLK_OF_DECLARE(sun8i_a33_ccu, "allwinner,sun8i-a33-ccu",
 	       sun8i_a33_ccu_setup);
-- 
2.11.0

Re: [PATCH 1/6] clk: sunxi-ng: fix PLL_CPUX adjusting on A33

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 462 bytes --]

On Tue, Dec 13, 2016 at 11:22:47PM +0800, Icenowy Zheng wrote:
> When adjusting PLL_CPUX on A33, the PLL is temporarily driven too high,
> and the system hangs.
> 
> Add a notifier to avoid this situation by temporarily switching to a
> known stable 24 MHz oscillator.
> 
> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>

Applied, thanks!
Maxime

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[PATCH 2/6] clk: sunxi-ng: set the parent rate when adjustin CPUX clock on A33

[Icenowy Zheng]

The CPUX clock on A33, which is for the Cortex-A7 cores, is designed to
be changeable by changing the rate of PLL_CPUX.

Add CLK_SET_RATE_PARENT flag to this clock.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
---
 drivers/clk/sunxi-ng/ccu-sun8i-a33.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
index 0f3e7d2dc19a..0d513d2674cb 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
@@ -170,7 +170,7 @@ static SUNXI_CCU_N_WITH_GATE_LOCK(pll_ddr1_clk, "pll-ddr1",
 static const char * const cpux_parents[] = { "osc32k", "osc24M",
 					     "pll-cpux" , "pll-cpux" };
 static SUNXI_CCU_MUX(cpux_clk, "cpux", cpux_parents,
-		     0x050, 16, 2, CLK_IS_CRITICAL);
+		     0x050, 16, 2, CLK_IS_CRITICAL | CLK_SET_RATE_PARENT);
 
 static SUNXI_CCU_M(axi_clk, "axi", "cpux", 0x050, 0, 2, 0);
 
-- 
2.11.0

Re: [PATCH 2/6] clk: sunxi-ng: set the parent rate when adjustin CPUX clock on A33

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 481 bytes --]

On Tue, Dec 13, 2016 at 11:22:48PM +0800, Icenowy Zheng wrote:
> The CPUX clock on A33, which is for the Cortex-A7 cores, is designed to
> be changeable by changing the rate of PLL_CPUX.
> 
> Add CLK_SET_RATE_PARENT flag to this clock.
> 
> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>

Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Thanks!
Maxime

-- 
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Embedded Linux and Kernel engineering
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Re: [PATCH 2/6] clk: sunxi-ng: set the parent rate when adjustin CPUX clock on A33

[Icenowy Zheng]

13.12.2016, 23:44, "Maxime Ripard" <maxime.ripard@free-electrons.com>:
> On Tue, Dec 13, 2016 at 11:22:48PM +0800, Icenowy Zheng wrote:
>>  The CPUX clock on A33, which is for the Cortex-A7 cores, is designed to
>>  be changeable by changing the rate of PLL_CPUX.
>>
>>  Add CLK_SET_RATE_PARENT flag to this clock.
>>
>>  Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
>
> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Excuse me, have you merged this patch?

If merged, I won't contain it in my PATCH v2, thus the PATCH v2 will contain
only an updated OPP patch.

>
> Thanks!
> Maxime
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com

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Re: [PATCH 2/6] clk: sunxi-ng: set the parent rate when adjustin CPUX clock on A33

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 733 bytes --]

On Wed, Dec 14, 2016 at 04:54:14AM +0800, Icenowy Zheng wrote:
> 
> 
> 13.12.2016, 23:44, "Maxime Ripard" <maxime.ripard@free-electrons.com>:
> > On Tue, Dec 13, 2016 at 11:22:48PM +0800, Icenowy Zheng wrote:
> >>  The CPUX clock on A33, which is for the Cortex-A7 cores, is designed to
> >>  be changeable by changing the rate of PLL_CPUX.
> >>
> >>  Add CLK_SET_RATE_PARENT flag to this clock.
> >>
> >>  Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
> >
> > Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> 
> Excuse me, have you merged this patch?

Yes, sorry, that's what I meant :)

Maxime

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[PATCH 3/6] ARM: dts: sun8i: add a cpu0 label to cpu@0 node on A23/33

[Icenowy Zheng]

A "cpu0" label is needed on cpu@0 for cpufreq-dt to work.

Add such a label, in order to prepare for cpufreq support of A23/33.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
---
 arch/arm/boot/dts/sun8i-a23-a33.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/sun8i-a23-a33.dtsi b/arch/arm/boot/dts/sun8i-a23-a33.dtsi
index 817747f41288..5931cc4d1567 100644
--- a/arch/arm/boot/dts/sun8i-a23-a33.dtsi
+++ b/arch/arm/boot/dts/sun8i-a23-a33.dtsi
@@ -84,7 +84,7 @@
 		#address-cells = <1>;
 		#size-cells = <0>;
 
-		cpu@0 {
+		cpu0: cpu@0 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			reg = <0>;
-- 
2.11.0

Re: [PATCH 3/6] ARM: dts: sun8i: add a cpu0 label to cpu@0 node on A23/33

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 388 bytes --]

On Tue, Dec 13, 2016 at 11:22:49PM +0800, Icenowy Zheng wrote:
> A "cpu0" label is needed on cpu@0 for cpufreq-dt to work.
> 
> Add such a label, in order to prepare for cpufreq support of A23/33.
> 
> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>

Applied, thanks!
Maxime

-- 
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Embedded Linux and Kernel engineering
http://free-electrons.com

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Re: [PATCH 3/6] ARM: dts: sun8i: add a cpu0 label to cpu@0 node on A23/33

[Sudeep Holla]

On 13/12/16 15:22, Icenowy Zheng wrote:
> A "cpu0" label is needed on cpu@0 for cpufreq-dt to work.
> 

IIUC any label should be fine and I don't see anything in the driver
looking for such label name. All I see is it looks for cpu0 regulator
for *legacy* DTs

> Add such a label, in order to prepare for cpufreq support of A23/33.
> 

You need this as you add the same label in the following patches. The
commit message sounds like cpufreq-dt search for that label by name.

-- 
Regards,
Sudeep

Re: [PATCH 3/6] ARM: dts: sun8i: add a cpu0 label to cpu@0 node on A23/33

[Chen-Yu Tsai]

On Wed, Dec 14, 2016 at 12:09 AM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>
>
> On 13/12/16 15:22, Icenowy Zheng wrote:
>> A "cpu0" label is needed on cpu@0 for cpufreq-dt to work.
>>
>
> IIUC any label should be fine and I don't see anything in the driver
> looking for such label name. All I see is it looks for cpu0 regulator
> for *legacy* DTs
>
>> Add such a label, in order to prepare for cpufreq support of A23/33.
>>
>
> You need this as you add the same label in the following patches. The
> commit message sounds like cpufreq-dt search for that label by name.

I think a more proper explanation would be:

The cpu's supply regulator is specified at the board level, hence we
need to add a label to it to reference it without replicating the whole
tree structure.

ChenYu

Re: [PATCH 3/6] ARM: dts: sun8i: add a cpu0 label to cpu@0 node on A23/33

[Sudeep Holla]

On 13/12/16 16:31, Chen-Yu Tsai wrote:
> On Wed, Dec 14, 2016 at 12:09 AM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>>
>>
>> On 13/12/16 15:22, Icenowy Zheng wrote:
>>> A "cpu0" label is needed on cpu@0 for cpufreq-dt to work.
>>>
>>
>> IIUC any label should be fine and I don't see anything in the driver
>> looking for such label name. All I see is it looks for cpu0 regulator
>> for *legacy* DTs
>>
>>> Add such a label, in order to prepare for cpufreq support of A23/33.
>>>
>>
>> You need this as you add the same label in the following patches. The
>> commit message sounds like cpufreq-dt search for that label by name.
> 
> I think a more proper explanation would be:
> 
> The cpu's supply regulator is specified at the board level, hence we
> need to add a label to it to reference it without replicating the whole
> tree structure.

Thanks for clarifying, was confused based on the commit log.

-- 
Regards,
Sudeep

[PATCH 4/6] ARM: dts: sun8i: add opp-v2 table for A33

[Icenowy Zheng]

An operating point table is needed for the cpu frequency adjusting to
work.

The operating point table is converted from the common value in
extracted script.fex from many A33 board/tablets.

1.344GHz is set as a turbo-mode operating point, as it's described as
"extremity_freq" in the FEX file. (the "max_freq" is 1.2GHz)

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
---
 arch/arm/boot/dts/sun8i-a33.dtsi | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/arch/arm/boot/dts/sun8i-a33.dtsi b/arch/arm/boot/dts/sun8i-a33.dtsi
index 504996cbee29..035c058324b8 100644
--- a/arch/arm/boot/dts/sun8i-a33.dtsi
+++ b/arch/arm/boot/dts/sun8i-a33.dtsi
@@ -46,7 +46,45 @@
 #include <dt-bindings/dma/sun4i-a10.h>
 
 / {
+	cpu0_opp_table: opp_table0 {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp@648000000 {
+			opp-hz = /bits/ 64 <648000000>;
+			opp-microvolt = <1040000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+		opp@816000000 {
+			opp-hz = /bits/ 64 <816000000>;
+			opp-microvolt = <1100000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+		opp@1008000000 {
+			opp-hz = /bits/ 64 <1008000000>;
+			opp-microvolt = <1200000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+		opp@1200000000 {
+			opp-hz = /bits/ 64 <1200000000>;
+			opp-microvolt = <1320000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+		};
+		opp@1344000000 {
+			opp-hz = /bits/ 64 <1344000000>;
+			opp-microvolt = <1460000>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+			turbo-mode;
+		};
+	};
+
 	cpus {
+		cpu0: cpu@0 {
+			clocks = <&ccu CLK_CPUX>;
+			clock-names = "cpu";
+			operating-points-v2 = <&cpu0_opp_table>;
+		};
+
 		cpu@2 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
-- 
2.11.0

Re: [PATCH 4/6] ARM: dts: sun8i: add opp-v2 table for A33

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 2286 bytes --]

On Tue, Dec 13, 2016 at 11:22:50PM +0800, Icenowy Zheng wrote:
> An operating point table is needed for the cpu frequency adjusting to
> work.
> 
> The operating point table is converted from the common value in
> extracted script.fex from many A33 board/tablets.
> 
> 1.344GHz is set as a turbo-mode operating point, as it's described as
> "extremity_freq" in the FEX file. (the "max_freq" is 1.2GHz)
> 
> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
> ---
>  arch/arm/boot/dts/sun8i-a33.dtsi | 38 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/sun8i-a33.dtsi b/arch/arm/boot/dts/sun8i-a33.dtsi
> index 504996cbee29..035c058324b8 100644
> --- a/arch/arm/boot/dts/sun8i-a33.dtsi
> +++ b/arch/arm/boot/dts/sun8i-a33.dtsi
> @@ -46,7 +46,45 @@
>  #include <dt-bindings/dma/sun4i-a10.h>
>  
>  / {
> +	cpu0_opp_table: opp_table0 {
> +		compatible = "operating-points-v2";
> +		opp-shared;
> +
> +		opp@648000000 {
> +			opp-hz = /bits/ 64 <648000000>;
> +			opp-microvolt = <1040000>;
> +			clock-latency-ns = <244144>; /* 8 32k periods */
> +		};

Please add new lines between the nodes.

> +		opp@816000000 {
> +			opp-hz = /bits/ 64 <816000000>;
> +			opp-microvolt = <1100000>;
> +			clock-latency-ns = <244144>; /* 8 32k periods */
> +		};
> +		opp@1008000000 {
> +			opp-hz = /bits/ 64 <1008000000>;
> +			opp-microvolt = <1200000>;
> +			clock-latency-ns = <244144>; /* 8 32k periods */
> +		};
> +		opp@1200000000 {
> +			opp-hz = /bits/ 64 <1200000000>;
> +			opp-microvolt = <1320000>;
> +			clock-latency-ns = <244144>; /* 8 32k periods */
> +		};
> +		opp@1344000000 {
> +			opp-hz = /bits/ 64 <1344000000>;
> +			opp-microvolt = <1460000>;
> +			clock-latency-ns = <244144>; /* 8 32k periods */
> +			turbo-mode;
> +		};

As far as I know, this OPP is not used by Allwinner, is not usable in
any A33 board so far (both the A33-olinuxino and the SinA33 do not
allow such a voltage on their CPU regulator), and overvolting and
overclocking is something that is very risky, and might lead to
stability issues.

Please remove this OPP.

Maxime

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[PATCH 5/6] ARM: dts: sun8i: set cpu-supply in reference tablet DTSI

[Icenowy Zheng]

All reference design A33 tablets uses DCDC2 of AXP223 as the power
supply of the Cortex-A7 cores.

Set the cpu-supply in the DTSI of sun8i reference tablets.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
---
 arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi b/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi
index 08cd00143635..7ac8bb4bc95a 100644
--- a/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi
+++ b/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi
@@ -213,6 +213,10 @@
 	regulator-name = "vcc-rtc";
 };
 
+&cpu0 {
+	cpu-supply = <&reg_dcdc2>;
+};
+
 &r_uart {
 	pinctrl-names = "default";
 	pinctrl-0 = <&r_uart_pins_a>;
-- 
2.11.0

Re: [PATCH 5/6] ARM: dts: sun8i: set cpu-supply in reference tablet DTSI

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 422 bytes --]

On Tue, Dec 13, 2016 at 11:22:51PM +0800, Icenowy Zheng wrote:
> All reference design A33 tablets uses DCDC2 of AXP223 as the power
> supply of the Cortex-A7 cores.
> 
> Set the cpu-supply in the DTSI of sun8i reference tablets.
> 
> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>

Applied, thanks

Maxime

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[PATCH 6/6] ARM: dts: sun8i: raise the max voltage of DCDC2 in sun8i reference tablets

[Icenowy Zheng]

The "extremity_freq" frequency described in the original FEX files uses
a voltage of 1.46v, which is beyond the current maximum voltage value of
DCDC2 (Cortex-A7 supply) in the sun8i reference tablet DTSI file.

Raise the maximum value to 1.46v.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
---
 arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi b/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi
index 7ac8bb4bc95a..325ca5bd67a5 100644
--- a/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi
+++ b/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi
@@ -180,7 +180,7 @@
 &reg_dcdc2 {
 	regulator-always-on;
 	regulator-min-microvolt = <900000>;
-	regulator-max-microvolt = <1400000>;
+	regulator-max-microvolt = <1460000>;
 	regulator-name = "vdd-sys";
 };
 
-- 
2.11.0

Re: [PATCH 6/6] ARM: dts: sun8i: raise the max voltage of DCDC2 in sun8i reference tablets

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 1168 bytes --]

On Tue, Dec 13, 2016 at 11:22:52PM +0800, Icenowy Zheng wrote:
> The "extremity_freq" frequency described in the original FEX files uses
> a voltage of 1.46v, which is beyond the current maximum voltage value of
> DCDC2 (Cortex-A7 supply) in the sun8i reference tablet DTSI file.
> 
> Raise the maximum value to 1.46v.
> 
> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
> ---
>  arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi b/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi
> index 7ac8bb4bc95a..325ca5bd67a5 100644
> --- a/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi
> +++ b/arch/arm/boot/dts/sun8i-reference-design-tablet.dtsi
> @@ -180,7 +180,7 @@
>  &reg_dcdc2 {
>  	regulator-always-on;
>  	regulator-min-microvolt = <900000>;
> -	regulator-max-microvolt = <1400000>;
> +	regulator-max-microvolt = <1460000>;

This is outside of the voltage range tolerated by the CPU. NAK.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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