cpufreq: ARM big LITTLE: Add Vexpress glue driver

Vexpress depends on motherboard firmware + spc for getting opp table. This patch
adds Vexpress glue driver for ARM big LITTLE parent driver.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

3 files changed, 94 insertions, 0 deletions

diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 9c6a69112e8..203e8959bde 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -15,6 +15,14 @@ config ARM_DT_BL_CPUFREQ
 	  This enables probing via DT for Generic CPUfreq driver for ARM
 	  big.LITTLE platform. This gets frequency tables from DT.
 
+config ARM_VEXPRESS_BL_CPUFREQ
+	tristate "ARM Vexpress big LITTLE CPUfreq driver"
+	select ARM_BIG_LITTLE_CPUFREQ
+	depends on ARM_SPC
+	help
+	  This enables the CPUfreq driver for ARM Vexpress big.LITTLE platform.
+	  If in doubt, say N.
+
 config ARM_EXYNOS_CPUFREQ
 	bool "SAMSUNG EXYNOS SoCs"
 	depends on ARCH_EXYNOS
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 315b9231feb..1db9b4929cf 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_X86_AMD_FREQ_SENSITIVITY)	+= amd_freq_sensitivity.o
 obj-$(CONFIG_ARM_BIG_LITTLE_CPUFREQ)	+= arm_big_little.o
 # big LITTLE per platform glues. Keep DT_BL_CPUFREQ as the last entry in all big
 # LITTLE drivers, so that it is probed last.
+obj-$(CONFIG_ARM_VEXPRESS_BL_CPUFREQ)	+= vexpress_big_little.o
 obj-$(CONFIG_ARM_DT_BL_CPUFREQ)		+= arm_big_little_dt.o
 
 obj-$(CONFIG_ARCH_DAVINCI_DA850)	+= davinci-cpufreq.o
diff --git a/drivers/cpufreq/vexpress_big_little.c b/drivers/cpufreq/vexpress_big_little.c
new file mode 100644
index 00000000000..aac24620704
--- /dev/null
+++ b/drivers/cpufreq/vexpress_big_little.c
@@ -0,0 +1,85 @@
+/*
+ * Vexpress big.LITTLE CPUFreq Interface driver
+ *
+ * It provides necessary ops to arm_big_little cpufreq driver and gets
+ * Frequency information from Device Tree. Freq table in DT must be in KHz.
+ *
+ * Copyright (C) 2013 Linaro.
+ * Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cpufreq.h>
+#include <linux/export.h>
+#include <linux/opp.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/vexpress.h>
+#include "arm_big_little.h"
+
+static int vexpress_init_opp_table(struct device *cpu_dev)
+{
+	int i = -1, count, cluster = cpu_to_cluster(cpu_dev->id);
+	unsigned int *table = vexpress_spc_get_freq_table(cluster, &count);
+	int ret;
+
+	if (!table || !count) {
+		pr_err("SPC controller returned invalid freq table");
+		return -EINVAL;
+	}
+
+	while (++i < count) {
+		/* FIXME: Voltage value */
+		ret = opp_add(cpu_dev, table[i] * 1000, 900000);
+		if (ret) {
+			dev_warn(cpu_dev, "%s: Failed to add OPP %d, err: %d\n",
+				 __func__, table[i] * 1000, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int vexpress_get_transition_latency(struct device *cpu_dev)
+{
+	/* 1 ms */
+	return 1000000;
+}
+
+static struct cpufreq_arm_bL_ops vexpress_bL_ops = {
+	.name	= "vexpress-bL",
+	.get_transition_latency = vexpress_get_transition_latency,
+	.init_opp_table = vexpress_init_opp_table,
+};
+
+static int vexpress_bL_init(void)
+{
+	if (!vexpress_spc_check_loaded()) {
+		pr_info("%s: No SPC found\n", __func__);
+		return -ENOENT;
+	}
+
+	return bL_cpufreq_register(&vexpress_bL_ops);
+}
+module_init(vexpress_bL_init);
+
+static void vexpress_bL_exit(void)
+{
+	return bL_cpufreq_unregister(&vexpress_bL_ops);
+}
+module_exit(vexpress_bL_exit);
+
+MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
+MODULE_DESCRIPTION("ARM Vexpress big LITTLE cpufreq driver");
+MODULE_LICENSE("GPL");