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[PICKME 0/2] cpufreq: New ST driver

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  [PICKME 0/2] cpufreq: New ST driver Lee Jones <lee.jones@linaro.org> - 2015-12-10 10:50 +0100
    [PICKME 1/2] cpufreq: st: Provide runtime initialised driver for ST's platforms Lee Jones <lee.jones@linaro.org> - 2015-12-10 10:50 +0100
    [PICKME 2/2] dt: cpufreq: st: Provide bindings for ST's CPUFreq implementation Lee Jones <lee.jones@linaro.org> - 2015-12-10 10:50 +0100
    Re: [PICKME 0/2] cpufreq: New ST driver "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-10 22:10 +0100
      Re: [PICKME 0/2] cpufreq: New ST driver Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-11 04:20 +0100
        Re: [PICKME 0/2] cpufreq: New ST driver Lee Jones <lee.jones@linaro.org> - 2015-12-11 08:10 +0100

#1288405 — [PICKME 0/2] cpufreq: New ST driver

Hi Rafael,

Would you be kind enough to pick these 2 patches up please.
The have the required Acks.

Kind regards,
Lee

This is a re-write of the original submission, hence why the
change-log is omitted.  Basically almost everything has changed.
We are now using the new OPP framework and generic bindings
written by Viresh.
  
There are 'ARM' patches in the set which are not necessarily
related to CPUFreq, but are required to get it to work. Anyone
who is not interested in general STi DT changes can safely
ignore these.
  
v5 => v6:
 - Converted Kconfig and header comment to describe new driver
 - Complete re-write, using new Generic OPP framework
 - Supply description for "suitable for ALL versions" DEFINE
 - Pedantically re-ordered the #include files
 - Removed platform device registration in arch/arm/mach-sti

v4 => v5:
 - Converted driver away from being a platform device
  
v1 => v2 => v3 => v4:
 - Moot

Lee Jones (2):
  cpufreq: st: Provide runtime initialised driver for ST's platforms
  dt: cpufreq: st: Provide bindings for ST's CPUFreq implementation

 .../devicetree/bindings/cpufreq/cpufreq-st.txt     |  91 +++++++
 drivers/cpufreq/Kconfig.arm                        |  10 +
 drivers/cpufreq/Makefile                           |   1 +
 drivers/cpufreq/sti-cpufreq.c                      | 294 +++++++++++++++++++++
 4 files changed, 396 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
 create mode 100644 drivers/cpufreq/sti-cpufreq.c

-- 
1.9.1

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#1288406 — [PICKME 1/2] cpufreq: st: Provide runtime initialised driver for ST's platforms

The bootloader is charged with the responsibility to provide platform
specific Dynamic Voltage and Frequency Scaling (DVFS) information via
Device Tree.  This driver takes the supplied configuration and
registers it with the new generic OPP framework, to then be used with
CPUFreq.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/cpufreq/Kconfig.arm   |  10 ++
 drivers/cpufreq/Makefile      |   1 +
 drivers/cpufreq/sti-cpufreq.c | 294 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 305 insertions(+)
 create mode 100644 drivers/cpufreq/sti-cpufreq.c

diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 1582c1c..2dfc327 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -216,6 +216,16 @@ config ARM_SPEAR_CPUFREQ
 	help
 	  This adds the CPUFreq driver support for SPEAr SOCs.
 
+config ARM_STI_CPUFREQ
+	tristate "STi CPUFreq support"
+	depends on SOC_STIH407
+	help
+	  This driver uses the generic OPP framework to match the running
+	  platform with a predefined set of suitable values.  If not provided
+	  we will fall-back so safe-values contained in Device Tree.  Enable
+	  this config option if you wish to add CPUFreq support for STi based
+	  SoCs.
+
 config ARM_TEGRA20_CPUFREQ
 	bool "Tegra20 CPUFreq support"
 	depends on ARCH_TEGRA
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index c0af1a1..9e63fb1 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -73,6 +73,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ)	+= sa1100-cpufreq.o
 obj-$(CONFIG_ARM_SA1110_CPUFREQ)	+= sa1110-cpufreq.o
 obj-$(CONFIG_ARM_SCPI_CPUFREQ)		+= scpi-cpufreq.o
 obj-$(CONFIG_ARM_SPEAR_CPUFREQ)		+= spear-cpufreq.o
+obj-$(CONFIG_ARM_STI_CPUFREQ)		+= sti-cpufreq.o
 obj-$(CONFIG_ARM_TEGRA20_CPUFREQ)	+= tegra20-cpufreq.o
 obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)	+= tegra124-cpufreq.o
 obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ)	+= vexpress-spc-cpufreq.o
diff --git a/drivers/cpufreq/sti-cpufreq.c b/drivers/cpufreq/sti-cpufreq.c
new file mode 100644
index 0000000..a9c659f
--- /dev/null
+++ b/drivers/cpufreq/sti-cpufreq.c
@@ -0,0 +1,294 @@
+/*
+ * Match running platform with pre-defined OPP values for CPUFreq
+ *
+ * Author: Ajit Pal Singh <ajitpal.singh@st.com>
+ *         Lee Jones <lee.jones@linaro.org>
+ *
+ * Copyright (C) 2015 STMicroelectronics (R&D) Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License as
+ * published by the Free Software Foundation
+ */
+
+#include <linux/cpu.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/pm_opp.h>
+#include <linux/regmap.h>
+
+#define VERSION_ELEMENTS	3
+#define MAX_PCODE_NAME_LEN	7
+
+#define VERSION_SHIFT		28
+#define HW_INFO_INDEX		1
+#define MAJOR_ID_INDEX		1
+#define MINOR_ID_INDEX		2
+
+/*
+ * Only match on "suitable for ALL versions" entries
+ *
+ * This will be used with the BIT() macro.  It sets the
+ * top bit of a 32bit value and is equal to 0x80000000.
+ */
+#define DEFAULT_VERSION		31
+
+enum {
+	PCODE = 0,
+	SUBSTRATE,
+	DVFS_MAX_REGFIELDS,
+};
+
+/**
+ * ST CPUFreq Driver Data
+ *
+ * @cpu_node		CPU's OF node
+ * @syscfg_eng		Engineering Syscon register map
+ * @regmap		Syscon register map
+ */
+static struct sti_cpufreq_ddata {
+	struct device *cpu;
+	struct regmap *syscfg_eng;
+	struct regmap *syscfg;
+} ddata;
+
+static int sti_cpufreq_fetch_major(void) {
+	struct device_node *np = ddata.cpu->of_node;
+	struct device *dev = ddata.cpu;
+	unsigned int major_offset;
+	unsigned int socid;
+	int ret;
+
+	ret = of_property_read_u32_index(np, "st,syscfg",
+					 MAJOR_ID_INDEX, &major_offset);
+	if (ret) {
+		dev_err(dev, "No major number offset provided in %s [%d]\n",
+			np->full_name, ret);
+		return ret;
+	}
+
+	ret = regmap_read(ddata.syscfg, major_offset, &socid);
+	if (ret) {
+		dev_err(dev, "Failed to read major number from syscon [%d]\n",
+			ret);
+		return ret;
+	}
+
+	return ((socid >> VERSION_SHIFT) & 0xf) + 1;
+}
+
+static int sti_cpufreq_fetch_minor(void)
+{
+	struct device *dev = ddata.cpu;
+	struct device_node *np = dev->of_node;
+	unsigned int minor_offset;
+	unsigned int minid;
+	int ret;
+
+	ret = of_property_read_u32_index(np, "st,syscfg-eng",
+					 MINOR_ID_INDEX, &minor_offset);
+	if (ret) {
+		dev_err(dev,
+			"No minor number offset provided %s [%d]\n",
+			np->full_name, ret);
+		return ret;
+	}
+
+	ret = regmap_read(ddata.syscfg_eng, minor_offset, &minid);
+	if (ret) {
+		dev_err(dev,
+			"Failed to read the minor number from syscon [%d]\n",
+			ret);
+		return ret;
+	}
+
+	return minid & 0xf;
+}
+
+static int sti_cpufreq_fetch_regmap_field(const struct reg_field *reg_fields,
+					  int hw_info_offset, int field)
+{
+	struct regmap_field *regmap_field;
+	struct reg_field reg_field = reg_fields[field];
+	struct device *dev = ddata.cpu;
+	unsigned int value;
+	int ret;
+
+	reg_field.reg = hw_info_offset;
+	regmap_field = devm_regmap_field_alloc(dev,
+					       ddata.syscfg_eng,
+					       reg_field);
+	if (IS_ERR(regmap_field)) {
+		dev_err(dev, "Failed to allocate reg field\n");
+		return PTR_ERR(regmap_field);
+	}
+
+	ret = regmap_field_read(regmap_field, &value);
+	if (ret) {
+		dev_err(dev, "Failed to read %s code\n",
+			field ? "SUBSTRATE" : "PCODE");
+		return ret;
+	}
+
+	return value;
+}
+
+static const struct reg_field sti_stih407_dvfs_regfields[DVFS_MAX_REGFIELDS] = {
+	[PCODE]		= REG_FIELD(0, 16, 19),
+	[SUBSTRATE]	= REG_FIELD(0, 0, 2),
+};
+
+static const struct reg_field *sti_cpufreq_match(void)
+{
+	if (of_machine_is_compatible("st,stih407") ||
+	    of_machine_is_compatible("st,stih410"))
+		return sti_stih407_dvfs_regfields;
+
+	return NULL;
+}
+
+static int sti_cpufreq_set_opp_info(void)
+{
+	struct device *dev = ddata.cpu;
+	struct device_node *np = dev->of_node;
+	const struct reg_field *reg_fields;
+	unsigned int hw_info_offset;
+	unsigned int version[VERSION_ELEMENTS];
+	int pcode, substrate, major, minor;
+	int ret;
+	char name[MAX_PCODE_NAME_LEN];
+
+	reg_fields = sti_cpufreq_match();
+	if (!reg_fields) {
+		dev_err(dev, "This SoC doesn't support voltage scaling");
+		return -ENODEV;
+	}
+
+	ret = of_property_read_u32_index(np, "st,syscfg-eng",
+					 HW_INFO_INDEX, &hw_info_offset);
+	if (ret) {
+		dev_warn(dev, "Failed to read HW info offset from DT\n");
+		substrate = DEFAULT_VERSION;
+		pcode = 0;
+		goto use_defaults;
+	}
+
+	pcode = sti_cpufreq_fetch_regmap_field(reg_fields,
+					       hw_info_offset,
+					       PCODE);
+	if (pcode < 0) {
+		dev_warn(dev, "Failed to obtain process code\n");
+		/* Use default pcode */
+		pcode = 0;
+	}
+
+	substrate = sti_cpufreq_fetch_regmap_field(reg_fields,
+						   hw_info_offset,
+						   SUBSTRATE);
+	if (substrate) {
+		dev_warn(dev, "Failed to obtain substrate code\n");
+		/* Use default substrate */
+		substrate = DEFAULT_VERSION;
+	}
+
+use_defaults:
+	major = sti_cpufreq_fetch_major();
+	if (major < 0) {
+		dev_err(dev, "Failed to obtain major version\n");
+		/* Use default major number */
+		major = DEFAULT_VERSION;
+	}
+
+	minor = sti_cpufreq_fetch_minor();
+	if (minor < 0) {
+		dev_err(dev, "Failed to obtain minor version\n");
+		/* Use default minor number */
+		minor = DEFAULT_VERSION;
+	}
+
+	snprintf(name, MAX_PCODE_NAME_LEN, "pcode%d", pcode);
+
+	ret = dev_pm_opp_set_prop_name(dev, name);
+	if (ret) {
+		dev_err(dev, "Failed to set prop name\n");
+		return ret;
+	}
+
+	version[0] = BIT(major);
+	version[1] = BIT(minor);
+	version[2] = BIT(substrate);
+
+	ret = dev_pm_opp_set_supported_hw(dev, version, VERSION_ELEMENTS);
+	if (ret) {
+		dev_err(dev, "Failed to set supported hardware\n");
+		return ret;
+	}
+
+	dev_dbg(dev, "pcode: %d major: %d minor: %d substrate: %d\n",
+		pcode, major, minor, substrate);
+	dev_dbg(dev, "version[0]: %x version[1]: %x version[2]: %x\n",
+		version[0], version[1], version[2]);
+
+	return 0;
+}
+
+static int sti_cpufreq_fetch_syscon_regsiters(void)
+{
+	struct device *dev = ddata.cpu;
+	struct device_node *np = dev->of_node;
+
+	ddata.syscfg = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
+	if (IS_ERR(ddata.syscfg)) {
+		dev_err(dev,  "\"st,syscfg\" not supplied\n");
+		return PTR_ERR(ddata.syscfg);
+	}
+
+	ddata.syscfg_eng = syscon_regmap_lookup_by_phandle(np, "st,syscfg-eng");
+	if (IS_ERR(ddata.syscfg_eng)) {
+		dev_err(dev, "\"st,syscfg-eng\" not supplied\n");
+		return PTR_ERR(ddata.syscfg_eng);
+	}
+
+	return 0;
+}
+
+static int sti_cpufreq_init(void)
+{
+	int ret;
+
+	ddata.cpu = get_cpu_device(0);
+	if (!ddata.cpu) {
+		dev_err(ddata.cpu, "Failed to get device for CPU0\n");
+		goto skip_voltage_scaling;
+	}
+
+	if (!of_get_property(ddata.cpu->of_node, "operating-points-v2", NULL)) {
+		dev_err(ddata.cpu, "OPP-v2 not supported\n");
+		goto skip_voltage_scaling;
+	}
+
+	ret = sti_cpufreq_fetch_syscon_regsiters();
+	if (ret)
+		goto skip_voltage_scaling;
+
+	ret = sti_cpufreq_set_opp_info();
+	if (!ret)
+		goto register_cpufreq_dt;
+
+skip_voltage_scaling:
+	dev_err(ddata.cpu, "Not doing voltage scaling\n");
+
+register_cpufreq_dt:
+	platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
+
+	return 0;
+}
+module_init(sti_cpufreq_init);
+
+MODULE_DESCRIPTION("STMicroelectronics CPUFreq/OPP driver");
+MODULE_AUTHOR("Ajitpal Singh <ajitpal.singh@st.com>");
+MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

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#1288407 — [PICKME 2/2] dt: cpufreq: st: Provide bindings for ST's CPUFreq implementation

Cc: devicetree@vger.kernel.org
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 .../devicetree/bindings/cpufreq/cpufreq-st.txt     | 91 ++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt

diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
new file mode 100644
index 0000000..d91a02a
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
@@ -0,0 +1,91 @@
+Binding for ST's CPUFreq driver
+===============================
+
+ST's CPUFreq driver attempts to read 'process' and 'version' attributes
+from the SoC, then supplies the OPP framework with 'prop' and 'supported
+hardware' information respectively.  The framework is then able to read
+the DT and operate in the usual way.
+
+For more information about the expected DT format [See: ../opp/opp.txt].
+
+Frequency Scaling only
+----------------------
+
+No vendor specific driver required for this.
+
+Located in CPU's node:
+
+- operating-points		: [See: ../power/opp.txt]
+
+Example [safe]
+--------------
+
+cpus {
+	cpu@0 {
+				 /* kHz     uV   */
+		operating-points = <1500000 0
+				    1200000 0
+				    800000  0
+				    500000  0>;
+	};
+};
+
+Dynamic Voltage and Frequency Scaling (DVFS)
+--------------------------------------------
+
+This requires the ST CPUFreq driver to supply 'process' and 'version' info.
+
+Located in CPU's node:
+
+- operating-points-v2		: [See ../power/opp.txt]
+
+Example [unsafe]
+----------------
+
+cpus {
+	cpu@0 {
+		operating-points-v2	= <&cpu0_opp_table>;
+	};
+};
+
+cpu0_opp_table: opp_table {
+	compatible = "operating-points-v2";
+
+	/* ############################################################### */
+	/* # WARNING: Do not attempt to copy/replicate these nodes,      # */
+	/* #          they are only to be supplied by the bootloader !!! # */
+	/* ############################################################### */
+	opp0 {
+		/*			   Major       Minor       Substrate */
+		/*			   2           all         all       */
+		opp-supported-hw	= <0x00000004  0xffffffff  0xffffffff>;
+		opp-hz			= /bits/ 64 <1500000000>;
+		clock-latency-ns	= <10000000>;
+
+		opp-microvolt-pcode0	= <1200000>;
+		opp-microvolt-pcode1	= <1200000>;
+		opp-microvolt-pcode2	= <1200000>;
+		opp-microvolt-pcode3	= <1200000>;
+		opp-microvolt-pcode4	= <1170000>;
+		opp-microvolt-pcode5	= <1140000>;
+		opp-microvolt-pcode6	= <1100000>;
+		opp-microvolt-pcode7	= <1070000>;
+	};
+
+	opp1 {
+		/*			   Major       Minor       Substrate */
+		/*			   all         all         all       */
+		opp-supported-hw	= <0xffffffff  0xffffffff  0xffffffff>;
+		opp-hz			= /bits/ 64 <1200000000>;
+		clock-latency-ns	= <10000000>;
+
+		opp-microvolt-pcode0	= <1110000>;
+		opp-microvolt-pcode1	= <1150000>;
+		opp-microvolt-pcode2	= <1100000>;
+		opp-microvolt-pcode3	= <1080000>;
+		opp-microvolt-pcode4	= <1040000>;
+		opp-microvolt-pcode5	= <1020000>;
+		opp-microvolt-pcode6	= <980000>;
+		opp-microvolt-pcode7	= <930000>;
+	};
+};
-- 
1.9.1

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#1288929

On Thursday, December 10, 2015 09:42:15 AM Lee Jones wrote:
> Hi Rafael,
> 
> Would you be kind enough to pick these 2 patches up please.
> The have the required Acks.

I can do that.

Do they depend on anything special?

Thanks,
Rafael

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#1289085

On 10-12-15, 22:38, Rafael J. Wysocki wrote:
> Do they depend on anything special?

My opp-binding-parsing patches which you applied to bleeding-edge.
Yes, Lee should have mentioned that explicitly.

-- 
viresh
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#1289264

On Fri, 11 Dec 2015, Viresh Kumar wrote:
> On 10-12-15, 22:38, Rafael J. Wysocki wrote:
> > Do they depend on anything special?
> 
> My opp-binding-parsing patches which you applied to bleeding-edge.

I thought these had already been applied.

> Yes, Lee should have mentioned that explicitly.

Aye, apologies for that.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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