[PATCH v4 11/12] cpufreq: Add module to register cpufreq on Krait CPUs

[Sricharan R <sricharan@codeaurora.org>]

From: Stephen Boyd <sboyd@codeaurora.org>

Register a cpufreq-generic device whenever we detect that a
"qcom,krait" compatible CPU is present in DT.

Cc: <devicetree@vger.kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 .../devicetree/bindings/arm/msm/qcom,pvs.txt       |  38 ++++
 drivers/cpufreq/Kconfig.arm                        |   9 +
 drivers/cpufreq/Makefile                           |   1 +
 drivers/cpufreq/qcom-cpufreq.c                     | 204 +++++++++++++++++++++
 4 files changed, 252 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,pvs.txt
 create mode 100644 drivers/cpufreq/qcom-cpufreq.c

diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,pvs.txt b/Documentation/devicetree/bindings/arm/msm/qcom,pvs.txt
new file mode 100644
index 0000000..e7cb104
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/msm/qcom,pvs.txt
@@ -0,0 +1,38 @@
+Qualcomm Process Voltage Scaling Tables
+
+The node name is required to be "qcom,pvs". There shall only be one
+such node present in the root of the tree.
+
+PROPERTIES
+
+- qcom,pvs-format-a or qcom,pvs-format-b:
+	Usage: required
+	Value type: <empty>
+	Definition: Indicates the format of qcom,speedX-pvsY-bin-vZ properties.
+		    If qcom,pvs-format-a is used the table is two columns
+		    (frequency and voltage in that order). If qcom,pvs-format-b 		    is used the table is three columns (frequency, voltage,
+		    and current in that order).
+
+- qcom,speedX-pvsY-bin-vZ:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: The PVS table corresponding to the speed bin X, pvs bin Y,
+		    and version Z.
+Example:
+
+	qcom,pvs {
+		qcom,pvs-format-a;
+		qcom,speed0-pvs0-bin-v0 =
+			<  384000000  950000 >,
+			<  486000000  975000 >,
+			<  594000000 1000000 >,
+			<  702000000 1025000 >,
+			<  810000000 1075000 >,
+			<  918000000 1100000 >,
+			< 1026000000 1125000 >,
+			< 1134000000 1175000 >,
+			< 1242000000 1200000 >,
+			< 1350000000 1225000 >,
+			< 1458000000 1237500 >,
+			< 1512000000 1250000 >;
+	};
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index bdce448..60f28e7 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -100,6 +100,15 @@ config ARM_OMAP2PLUS_CPUFREQ
 	depends on ARCH_OMAP2PLUS
 	default ARCH_OMAP2PLUS
 
+config ARM_QCOM_CPUFREQ
+	tristate "Qualcomm based"
+	depends on ARCH_QCOM
+	select PM_OPP
+	help
+	  This adds the CPUFreq driver for Qualcomm SoC based boards.
+
+	  If in doubt, say N.
+
 config ARM_S3C_CPUFREQ
 	bool
 	help
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 812f9e0..1496464 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -62,6 +62,7 @@ obj-$(CONFIG_ARM_MEDIATEK_CPUFREQ)	+= mediatek-cpufreq.o
 obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ)	+= omap-cpufreq.o
 obj-$(CONFIG_ARM_PXA2xx_CPUFREQ)	+= pxa2xx-cpufreq.o
 obj-$(CONFIG_PXA3xx)			+= pxa3xx-cpufreq.o
+obj-$(CONFIG_ARM_QCOM_CPUFREQ)		+= qcom-cpufreq.o
 obj-$(CONFIG_ARM_S3C24XX_CPUFREQ)	+= s3c24xx-cpufreq.o
 obj-$(CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS) += s3c24xx-cpufreq-debugfs.o
 obj-$(CONFIG_ARM_S3C2410_CPUFREQ)	+= s3c2410-cpufreq.o
diff --git a/drivers/cpufreq/qcom-cpufreq.c b/drivers/cpufreq/qcom-cpufreq.c
new file mode 100644
index 0000000..95ed2ba
--- /dev/null
+++ b/drivers/cpufreq/qcom-cpufreq.c
@@ -0,0 +1,204 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/slab.h>
+#include "cpufreq-dt.h"
+
+static void __init get_krait_bin_format_a(int *speed, int *pvs, int *pvs_ver)
+{
+	void __iomem *base;
+	u32 pte_efuse;
+
+	*speed = *pvs = *pvs_ver = 0;
+
+	base = ioremap(0x007000c0, 4);
+	if (!base) {
+		pr_warn("Unable to read efuse data. Defaulting to 0!\n");
+		return;
+	}
+
+	pte_efuse = readl_relaxed(base);
+	iounmap(base);
+
+	*speed = pte_efuse & 0xf;
+	if (*speed == 0xf)
+		*speed = (pte_efuse >> 4) & 0xf;
+
+	if (*speed == 0xf) {
+		*speed = 0;
+		pr_warn("Speed bin: Defaulting to %d\n", *speed);
+	} else {
+		pr_info("Speed bin: %d\n", *speed);
+	}
+
+	*pvs = (pte_efuse >> 10) & 0x7;
+	if (*pvs == 0x7)
+		*pvs = (pte_efuse >> 13) & 0x7;
+
+	if (*pvs == 0x7) {
+		*pvs = 0;
+		pr_warn("PVS bin: Defaulting to %d\n", *pvs);
+	} else {
+		pr_info("PVS bin: %d\n", *pvs);
+	}
+}
+
+static void __init get_krait_bin_format_b(int *speed, int *pvs, int *pvs_ver)
+{
+	u32 pte_efuse, redundant_sel;
+	void __iomem *base;
+
+	*speed = 0;
+	*pvs = 0;
+	*pvs_ver = 0;
+
+	base = ioremap(0xfc4b80b0, 8);
+	if (!base) {
+		pr_warn("Unable to read efuse data. Defaulting to 0!\n");
+		return;
+	}
+
+	pte_efuse = readl_relaxed(base);
+	redundant_sel = (pte_efuse >> 24) & 0x7;
+	*speed = pte_efuse & 0x7;
+	/* 4 bits of PVS are in efuse register bits 31, 8-6. */
+	*pvs = ((pte_efuse >> 28) & 0x8) | ((pte_efuse >> 6) & 0x7);
+	*pvs_ver = (pte_efuse >> 4) & 0x3;
+
+	switch (redundant_sel) {
+	case 1:
+		*speed = (pte_efuse >> 27) & 0xf;
+		break;
+	case 2:
+		*pvs = (pte_efuse >> 27) & 0xf;
+		break;
+	}
+
+	/* Check SPEED_BIN_BLOW_STATUS */
+	if (pte_efuse & BIT(3)) {
+		pr_info("Speed bin: %d\n", *speed);
+	} else {
+		pr_warn("Speed bin not set. Defaulting to 0!\n");
+		*speed = 0;
+	}
+
+	/* Check PVS_BLOW_STATUS */
+	pte_efuse = readl_relaxed(base + 0x4) & BIT(21);
+	if (pte_efuse) {
+		pr_info("PVS bin: %d\n", *pvs);
+	} else {
+		pr_warn("PVS bin not set. Defaulting to 0!\n");
+		*pvs = 0;
+	}
+
+	pr_info("PVS version: %d\n", *pvs_ver);
+	iounmap(base);
+}
+
+static int __init qcom_cpufreq_populate_opps(void)
+{
+	int len, rows, cols, i, k, speed, pvs, pvs_ver;
+	char table_name[] = "qcom,speedXX-pvsXX-bin-vXX";
+	struct device_node *np;
+	struct device *dev;
+	int cpu = 0;
+
+	np = of_find_node_by_name(NULL, "qcom,pvs");
+	if (!np)
+		return -ENODEV;
+
+	if (of_property_read_bool(np, "qcom,pvs-format-a")) {
+		get_krait_bin_format_a(&speed, &pvs, &pvs_ver);
+		cols = 2;
+	} else if (of_property_read_bool(np, "qcom,pvs-format-b")) {
+		get_krait_bin_format_b(&speed, &pvs, &pvs_ver);
+		cols = 3;
+	} else {
+		return -ENODEV;
+	}
+
+	snprintf(table_name, sizeof(table_name),
+		 "qcom,speed%d-pvs%d-bin-v%d", speed, pvs, pvs_ver);
+
+	if (!of_find_property(np, table_name, &len))
+		return -EINVAL;
+
+	len /= sizeof(u32);
+	if (len % cols || len == 0)
+		return -EINVAL;
+
+	rows = len / cols;
+
+	for (i = 0, k = 0; i < rows; i++) {
+		u32 freq, volt;
+
+		of_property_read_u32_index(np, table_name, k++, &freq);
+		of_property_read_u32_index(np, table_name, k++, &volt);
+		while (k % cols)
+			k++; /* Skip uA entries if present */
+		for (cpu = 0; cpu < num_possible_cpus(); cpu++) {
+			dev = get_cpu_device(cpu);
+			if (!dev)
+				return -ENODEV;
+			if (dev_pm_opp_add(dev, freq, volt))
+				pr_warn("failed to add OPP %u\n", freq);
+		}
+	}
+
+	return 0;
+}
+
+static int __init qcom_cpufreq_driver_init(void)
+{
+	struct cpufreq_dt_platform_data pdata = { .independent_clocks = true };
+	struct platform_device_info devinfo = {
+		.name = "cpufreq-dt",
+		.data = &pdata,
+		.size_data = sizeof(pdata),
+	};
+	struct device *cpu_dev;
+	struct device_node *np;
+	int ret;
+
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev)
+		return -ENODEV;
+
+	np = of_node_get(cpu_dev->of_node);
+	if (!np)
+		return -ENOENT;
+
+	if (!of_device_is_compatible(np, "qcom,krait")) {
+		of_node_put(np);
+		return -ENODEV;
+	}
+	of_node_put(np);
+
+	ret = qcom_cpufreq_populate_opps();
+	if (ret)
+		return ret;
+
+	return PTR_ERR_OR_ZERO(platform_device_register_full(&devinfo));
+}
+module_init(qcom_cpufreq_driver_init);
+
+MODULE_DESCRIPTION("Qualcomm CPUfreq driver");
+MODULE_LICENSE("GPL v2");
-- 
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