[PATCH v3 0/3] qcom-cpufreq-hw: Add CPU clock provider support

[PATCH v3 0/3] qcom-cpufreq-hw: Add CPU clock provider support

[Manivannan Sadhasivam]

Hello,

This series adds clock provider support to the Qcom CPUFreq driver for
supplying the clocks to the CPU cores in Qcom SoCs.

The Qualcomm platforms making use of CPUFreq HW Engine (EPSS/OSM) supply
clocks to the CPU cores. But this is not represented clearly in devicetree.
There is no clock coming out of the CPUFreq HW node to the CPU. This created
an issue [1] with the OPP core when a recent enhancement series was submitted.
Eventhough the issue got fixed in the OPP framework in the meantime, that's
not a proper solution and this series aims to fix it properly.

There was also an attempt made by Viresh [2] to fix the issue by moving the
clocks supplied to the CPUFreq HW node to the CPU. But that was not accepted
since those clocks belong to the CPUFreq HW node only.

The proposal here is to add clock provider support to the Qcom CPUFreq HW
driver to supply clocks to the CPUs that comes out of the EPSS/OSM block.
This correctly reflects the hardware implementation.

The clock provider is a simple one that just provides the frequency of the
clocks supplied to each frequency domain in the SoC using .recalc_rate()
callback. The frequency supplied by the driver will be the actual frequency
that comes out of the EPSS/OSM block after the DCVS operation. This frequency
is not same as what the CPUFreq framework has set but it is the one that gets
supplied to the CPUs after throttling by LMh.

This series has been tested on SM8450 based dev board with the OPP hack removed
and hence there is a DTS change only for that platform. Once this series gets
accepted, rest of the platform DTS can also be modified and finally the hack on
the OPP core can be dropped.

Thanks,
Mani

[1] https://lore.kernel.org/lkml/YsxSkswzsqgMOc0l@hovoldconsulting.com/
[2] https://lore.kernel.org/lkml/20220801054255.GA12039@thinkpad/t/

Changes in v3:

* Submitted the cpufreq driver cleanup patches as a separate series as
  suggested by Viresh
* Removed static keyword from clk_init_data declaration

Changes in v2:

* Moved the qcom_cpufreq_data allocation to probe
* Added single clock provider with multiple clks for each freq domain
* Moved soc_data to qcom_cpufreq struct
* Added Rob's review for binding

Manivannan Sadhasivam (3):
  dt-bindings: cpufreq: cpufreq-qcom-hw: Add cpufreq clock provider
  arm64: dts: qcom: sm8450: Supply clock from cpufreq node to CPUs
  cpufreq: qcom-hw: Add CPU clock provider support

 .../bindings/cpufreq/cpufreq-qcom-hw.yaml     | 12 ++++++
 arch/arm64/boot/dts/qcom/sm8450.dtsi          |  9 ++++
 drivers/cpufreq/qcom-cpufreq-hw.c             | 43 +++++++++++++++++++
 3 files changed, 64 insertions(+)

-- 
2.25.1

[PATCH v3 1/3] dt-bindings: cpufreq: cpufreq-qcom-hw: Add cpufreq clock provider

[Manivannan Sadhasivam]

Qualcomm platforms making use of CPUFreq HW Engine (EPSS/OSM) supply clocks
to the CPU cores. Document the same in the binding to reflect the actual
implementation.

CPUFreq HW will become the clock provider and CPU cores will become the
clock consumers.

The clock index for each CPU core is based on the frequency domain index.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 .../devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml b/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml
index cbba8979fe0e..2e0336163ffb 100644
--- a/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-hw.yaml
@@ -57,6 +57,9 @@ properties:
   '#freq-domain-cells':
     const: 1
 
+  '#clock-cells':
+    const: 1
+
 required:
   - compatible
   - reg
@@ -84,6 +87,7 @@ examples:
         enable-method = "psci";
         next-level-cache = <&L2_0>;
         qcom,freq-domain = <&cpufreq_hw 0>;
+        clocks = <&cpufreq_hw 0>;
         L2_0: l2-cache {
           compatible = "cache";
           next-level-cache = <&L3_0>;
@@ -100,6 +104,7 @@ examples:
         enable-method = "psci";
         next-level-cache = <&L2_100>;
         qcom,freq-domain = <&cpufreq_hw 0>;
+        clocks = <&cpufreq_hw 0>;
         L2_100: l2-cache {
           compatible = "cache";
           next-level-cache = <&L3_0>;
@@ -113,6 +118,7 @@ examples:
         enable-method = "psci";
         next-level-cache = <&L2_200>;
         qcom,freq-domain = <&cpufreq_hw 0>;
+        clocks = <&cpufreq_hw 0>;
         L2_200: l2-cache {
           compatible = "cache";
           next-level-cache = <&L3_0>;
@@ -126,6 +132,7 @@ examples:
         enable-method = "psci";
         next-level-cache = <&L2_300>;
         qcom,freq-domain = <&cpufreq_hw 0>;
+        clocks = <&cpufreq_hw 0>;
         L2_300: l2-cache {
           compatible = "cache";
           next-level-cache = <&L3_0>;
@@ -139,6 +146,7 @@ examples:
         enable-method = "psci";
         next-level-cache = <&L2_400>;
         qcom,freq-domain = <&cpufreq_hw 1>;
+        clocks = <&cpufreq_hw 1>;
         L2_400: l2-cache {
           compatible = "cache";
           next-level-cache = <&L3_0>;
@@ -152,6 +160,7 @@ examples:
         enable-method = "psci";
         next-level-cache = <&L2_500>;
         qcom,freq-domain = <&cpufreq_hw 1>;
+        clocks = <&cpufreq_hw 1>;
         L2_500: l2-cache {
           compatible = "cache";
           next-level-cache = <&L3_0>;
@@ -165,6 +174,7 @@ examples:
         enable-method = "psci";
         next-level-cache = <&L2_600>;
         qcom,freq-domain = <&cpufreq_hw 1>;
+        clocks = <&cpufreq_hw 1>;
         L2_600: l2-cache {
           compatible = "cache";
           next-level-cache = <&L3_0>;
@@ -178,6 +188,7 @@ examples:
         enable-method = "psci";
         next-level-cache = <&L2_700>;
         qcom,freq-domain = <&cpufreq_hw 1>;
+        clocks = <&cpufreq_hw 1>;
         L2_700: l2-cache {
           compatible = "cache";
           next-level-cache = <&L3_0>;
@@ -198,6 +209,7 @@ examples:
         clock-names = "xo", "alternate";
 
         #freq-domain-cells = <1>;
+        #clock-cells = <1>;
       };
     };
 ...
-- 
2.25.1

[PATCH v3 2/3] arm64: dts: qcom: sm8450: Supply clock from cpufreq node to CPUs

[Manivannan Sadhasivam]

Qualcomm platforms making use of CPUFreq HW Engine (EPSS/OSM) supply clocks
to the CPU cores. But this relationship is not represented in DTS so far.

So let's make cpufreq node as the clock provider and CPU nodes as the
consumers. The clock index for each CPU node is based on the frequency
domain index.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 arch/arm64/boot/dts/qcom/sm8450.dtsi | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sm8450.dtsi b/arch/arm64/boot/dts/qcom/sm8450.dtsi
index 6c18cfca9a34..8f26cf9aad01 100644
--- a/arch/arm64/boot/dts/qcom/sm8450.dtsi
+++ b/arch/arm64/boot/dts/qcom/sm8450.dtsi
@@ -52,6 +52,7 @@ CPU0: cpu@0 {
 			power-domain-names = "psci";
 			qcom,freq-domain = <&cpufreq_hw 0>;
 			#cooling-cells = <2>;
+			clocks = <&cpufreq_hw 0>;
 			L2_0: l2-cache {
 			      compatible = "cache";
 			      next-level-cache = <&L3_0>;
@@ -71,6 +72,7 @@ CPU1: cpu@100 {
 			power-domain-names = "psci";
 			qcom,freq-domain = <&cpufreq_hw 0>;
 			#cooling-cells = <2>;
+			clocks = <&cpufreq_hw 0>;
 			L2_100: l2-cache {
 			      compatible = "cache";
 			      next-level-cache = <&L3_0>;
@@ -87,6 +89,7 @@ CPU2: cpu@200 {
 			power-domain-names = "psci";
 			qcom,freq-domain = <&cpufreq_hw 0>;
 			#cooling-cells = <2>;
+			clocks = <&cpufreq_hw 0>;
 			L2_200: l2-cache {
 			      compatible = "cache";
 			      next-level-cache = <&L3_0>;
@@ -103,6 +106,7 @@ CPU3: cpu@300 {
 			power-domain-names = "psci";
 			qcom,freq-domain = <&cpufreq_hw 0>;
 			#cooling-cells = <2>;
+			clocks = <&cpufreq_hw 0>;
 			L2_300: l2-cache {
 			      compatible = "cache";
 			      next-level-cache = <&L3_0>;
@@ -119,6 +123,7 @@ CPU4: cpu@400 {
 			power-domain-names = "psci";
 			qcom,freq-domain = <&cpufreq_hw 1>;
 			#cooling-cells = <2>;
+			clocks = <&cpufreq_hw 1>;
 			L2_400: l2-cache {
 			      compatible = "cache";
 			      next-level-cache = <&L3_0>;
@@ -135,6 +140,7 @@ CPU5: cpu@500 {
 			power-domain-names = "psci";
 			qcom,freq-domain = <&cpufreq_hw 1>;
 			#cooling-cells = <2>;
+			clocks = <&cpufreq_hw 1>;
 			L2_500: l2-cache {
 			      compatible = "cache";
 			      next-level-cache = <&L3_0>;
@@ -152,6 +158,7 @@ CPU6: cpu@600 {
 			power-domain-names = "psci";
 			qcom,freq-domain = <&cpufreq_hw 1>;
 			#cooling-cells = <2>;
+			clocks = <&cpufreq_hw 1>;
 			L2_600: l2-cache {
 			      compatible = "cache";
 			      next-level-cache = <&L3_0>;
@@ -168,6 +175,7 @@ CPU7: cpu@700 {
 			power-domain-names = "psci";
 			qcom,freq-domain = <&cpufreq_hw 2>;
 			#cooling-cells = <2>;
+			clocks = <&cpufreq_hw 2>;
 			L2_700: l2-cache {
 			      compatible = "cache";
 			      next-level-cache = <&L3_0>;
@@ -3804,6 +3812,7 @@ cpufreq_hw: cpufreq@17d91000 {
 				     <GIC_SPI 19 IRQ_TYPE_LEVEL_HIGH>;
 			interrupt-names = "dcvsh-irq-0", "dcvsh-irq-1", "dcvsh-irq-2";
 			#freq-domain-cells = <1>;
+			#clock-cells = <1>;
 		};
 
 		gem_noc: interconnect@19100000 {
-- 
2.25.1

[PATCH v3 3/3] cpufreq: qcom-hw: Add CPU clock provider support

[Manivannan Sadhasivam]

Qcom CPUFreq hardware (EPSS/OSM) controls clock and voltage to the CPU
cores. But this relationship is not represented with the clk framework
so far.

So, let's make the qcom-cpufreq-hw driver a clock provider. This makes the
clock producer/consumer relationship cleaner and is also useful for CPU
related frameworks like OPP to know the frequency at which the CPUs are
running.

The clock frequency provided by the driver is for each frequency domain.
We cannot get the frequency of each CPU core because, not all platforms
support per-core DCVS feature.

Also the frequency supplied by the driver is the actual frequency that
comes out of the EPSS/OSM block after the DCVS operation. This frequency is
not same as what the CPUFreq framework has set but it is the one that gets
supplied to the CPUs after throttling by LMh.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/cpufreq/qcom-cpufreq-hw.c | 43 +++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index 76f840636828..b824f1bb04f4 100644
--- a/drivers/cpufreq/qcom-cpufreq-hw.c
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/bitfield.h>
+#include <linux/clk-provider.h>
 #include <linux/cpufreq.h>
 #include <linux/init.h>
 #include <linux/interconnect.h>
@@ -53,6 +54,7 @@ struct qcom_cpufreq_data {
 	bool cancel_throttle;
 	struct delayed_work throttle_work;
 	struct cpufreq_policy *policy;
+	struct clk_hw cpu_clk;
 
 	bool per_core_dcvs;
 };
@@ -601,8 +603,20 @@ static struct cpufreq_driver cpufreq_qcom_hw_driver = {
 	.ready		= qcom_cpufreq_ready,
 };
 
+static unsigned long qcom_cpufreq_hw_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+	struct qcom_cpufreq_data *data = container_of(hw, struct qcom_cpufreq_data, cpu_clk);
+
+	return qcom_lmh_get_throttle_freq(data) / HZ_PER_KHZ;
+}
+
+static const struct clk_ops qcom_cpufreq_hw_clk_ops = {
+	.recalc_rate = qcom_cpufreq_hw_recalc_rate,
+};
+
 static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
 {
+	struct clk_hw_onecell_data *clk_data;
 	struct device *dev = &pdev->dev;
 	struct device *cpu_dev;
 	struct clk *clk;
@@ -645,8 +659,16 @@ static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
 
 	qcom_cpufreq.soc_data = of_device_get_match_data(dev);
 
+	clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, num_domains), GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+
+	clk_data->num = num_domains;
+
 	for (i = 0; i < num_domains; i++) {
 		struct qcom_cpufreq_data *data = &qcom_cpufreq.data[i];
+		struct clk_init_data init = {};
+		const char *clk_name;
 		struct resource *res;
 		void __iomem *base;
 
@@ -658,6 +680,27 @@ static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
 
 		data->base = base;
 		data->res = res;
+
+		/* Register CPU clock for each frequency domain */
+		clk_name = devm_kasprintf(dev, GFP_KERNEL, "qcom_cpufreq%d", i);
+		init.name = clk_name;
+		init.flags = CLK_GET_RATE_NOCACHE;
+		init.ops = &qcom_cpufreq_hw_clk_ops;
+		data->cpu_clk.init = &init;
+
+		ret = devm_clk_hw_register(dev, &data->cpu_clk);
+		if (ret < 0) {
+			dev_err(dev, "Failed to register Qcom CPUFreq clock\n");
+			return ret;
+		}
+
+		clk_data->hws[i] = &data->cpu_clk;
+	}
+
+	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, clk_data);
+	if (ret < 0) {
+		dev_err(dev, "Failed to add Qcom CPUFreq clock provider\n");
+		return ret;
 	}
 
 	ret = cpufreq_register_driver(&cpufreq_qcom_hw_driver);
-- 
2.25.1