1 files changed, 303 insertions, 0 deletions
diff --git a/drivers/cpufreq/sti-cpufreq.c b/drivers/cpufreq/sti-cpufreq.c
new file mode 100644
index 0000000000..9c542e723a
--- /dev/null
+++ b/drivers/cpufreq/sti-cpufreq.c
@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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
+ */
+
+#include <linux/cpu.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.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,
+};
+
+/**
+ * struct sti_cpufreq_ddata - ST CPUFreq Driver Data
+ *
+ * @cpu:		CPU's OF node
+ * @syscfg_eng:		Engineering Syscon register map
+ * @syscfg:		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 %pOF [%d]\n",
+			np, 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 %pOF [%d]\n",
+			np, 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") ||
+	    of_machine_is_compatible("st,stih418"))
+		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 opp_token, ret;
+	char name[MAX_PCODE_NAME_LEN];
+	struct dev_pm_opp_config config = {
+		.supported_hw = version,
+		.supported_hw_count = ARRAY_SIZE(version),
+		.prop_name = name,
+	};
+
+	reg_fields = sti_cpufreq_match();
+	if (!reg_fields) {
+		dev_err(dev, "This SoC doesn't support voltage scaling\n");
+		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);
+
+	version[0] = BIT(major);
+	version[1] = BIT(minor);
+	version[2] = BIT(substrate);
+
+	opp_token = dev_pm_opp_set_config(dev, &config);
+	if (opp_token < 0) {
+		dev_err(dev, "Failed to set OPP config\n");
+		return opp_token;
+	}
+
+	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_registers(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 __init sti_cpufreq_init(void)
+{
+	int ret;
+
+	if ((!of_machine_is_compatible("st,stih407")) &&
+		(!of_machine_is_compatible("st,stih410")) &&
+		(!of_machine_is_compatible("st,stih418")))
+		return -ENODEV;
+
+	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_registers();
+	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);
+
+static const struct of_device_id __maybe_unused sti_cpufreq_of_match[] = {
+	{ .compatible = "st,stih407" },
+	{ .compatible = "st,stih410" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sti_cpufreq_of_match);
+
+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");