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authorSudeep Holla <sudeep.holla@arm.com>2015-07-23 12:10:25 +0100
committerJon Medhurst <tixy@linaro.org>2015-10-19 13:03:07 +0100
commit8566a66615d4ea43ec774030f890d5fe467f517a (patch)
tree53edb04002ffa0d4185a52444d5f107c48ad7713
parentf8f9ebb7bdfcb577d88e6e1caeef2c1d4d8c7b4b (diff)
cpufreq: arm_big_little: add SCPI interface driver
On some ARM based systems, a separate Cortex-M based System Control Processor(SCP) provides the overall power, clock, reset and system control including CPU DVFS. SCPI Message Protocol is used to communicate with the SCPI. This patch adds a interface driver for adding OPPs and registering the arm_big_little cpufreq driver for such systems. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linux-pm@vger.kernel.org Signed-off-by: Jon Medhurst <tixy@linaro.org>
-rw-r--r--MAINTAINERS1
-rw-r--r--drivers/cpufreq/Kconfig.arm9
-rw-r--r--drivers/cpufreq/Makefile1
-rw-r--r--drivers/cpufreq/scpi-cpufreq.c124
4 files changed, 135 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS
index a093c319a0df..07cb8801ae0d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8191,6 +8191,7 @@ L: linux-arm-kernel@lists.infradead.org
S: Maintained
F: Documentation/devicetree/bindings/arm/arm,scpi.txt
F: drivers/clk/clk-scpi.c
+F: drivers/cpufreq/scpi-cpufreq.c
F: drivers/firmware/arm_scpi.c
F: include/linux/scpi_protocol.h
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 182ad49a77be..aa6a665d8464 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -24,6 +24,15 @@ config ARM_VEXPRESS_SPC_CPUFREQ
This add the CPUfreq driver support for Versatile Express
big.LITTLE platforms using SPC for power management.
+config ARM_SCPI_CPUFREQ
+ tristate "SCPI based CPUfreq driver"
+ depends on ARM_BIG_LITTLE_CPUFREQ && ARM_SCPI_PROTOCOL
+ help
+ This adds the CPUfreq driver support for ARM big.LITTLE platforms
+ using SCPI protocol for CPU power management.
+
+ This driver uses SCPI Message Protocol driver to interact with the
+ firmware providing the CPU DVFS functionality.
config ARM_EXYNOS_CPUFREQ
bool
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 40c53dc1937e..88563dc7064b 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_ARM_SA1110_CPUFREQ) += sa1110-cpufreq.o
obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
obj-$(CONFIG_ARM_TEGRA_CPUFREQ) += tegra-cpufreq.o
obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
+obj-$(CONFIG_ARM_SCPI_CPUFREQ) += scpi-cpufreq.o
##################################################################################
# PowerPC platform drivers
diff --git a/drivers/cpufreq/scpi-cpufreq.c b/drivers/cpufreq/scpi-cpufreq.c
new file mode 100644
index 000000000000..2c3b16fd3a01
--- /dev/null
+++ b/drivers/cpufreq/scpi-cpufreq.c
@@ -0,0 +1,124 @@
+/*
+ * System Control and Power Interface (SCPI) based CPUFreq Interface driver
+ *
+ * It provides necessary ops to arm_big_little cpufreq driver.
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ * Sudeep Holla <sudeep.holla@arm.com>
+ *
+ * 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/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/scpi_protocol.h>
+#include <linux/types.h>
+
+#include "arm_big_little.h"
+
+static struct scpi_ops *scpi_ops;
+
+static struct scpi_dvfs_info *scpi_get_dvfs_info(struct device *cpu_dev)
+{
+ u8 domain = topology_physical_package_id(cpu_dev->id);
+
+ if (domain < 0)
+ return ERR_PTR(-EINVAL);
+ return scpi_ops->dvfs_get_info(domain);
+}
+
+static int scpi_opp_table_ops(struct device *cpu_dev, bool remove)
+{
+ int idx, ret = 0;
+ struct scpi_opp *opp;
+ struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev);
+
+ if (IS_ERR(info))
+ return PTR_ERR(info);
+
+ if (!info->opps)
+ return -EIO;
+
+ for (opp = info->opps, idx = 0; idx < info->count; idx++, opp++) {
+ if (remove)
+ dev_pm_opp_remove(cpu_dev, opp->freq);
+ else
+ ret = dev_pm_opp_add(cpu_dev, opp->freq,
+ opp->m_volt * 1000);
+ if (ret) {
+ dev_warn(cpu_dev, "failed to add opp %uHz %umV\n",
+ opp->freq, opp->m_volt);
+ while (idx-- > 0)
+ dev_pm_opp_remove(cpu_dev, (--opp)->freq);
+ return ret;
+ }
+ }
+ return ret;
+}
+
+static int scpi_get_transition_latency(struct device *cpu_dev)
+{
+ struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev);
+
+ if (IS_ERR(info))
+ return PTR_ERR(info);
+ return info->latency;
+}
+
+static int scpi_init_opp_table(struct device *cpu_dev)
+{
+ return scpi_opp_table_ops(cpu_dev, false);
+}
+
+static void scpi_free_opp_table(struct device *cpu_dev)
+{
+ scpi_opp_table_ops(cpu_dev, true);
+}
+
+static struct cpufreq_arm_bL_ops scpi_cpufreq_ops = {
+ .name = "scpi",
+ .get_transition_latency = scpi_get_transition_latency,
+ .init_opp_table = scpi_init_opp_table,
+ .free_opp_table = scpi_free_opp_table,
+};
+
+static int scpi_cpufreq_probe(struct platform_device *pdev)
+{
+ scpi_ops = get_scpi_ops();
+ if (!scpi_ops)
+ return -EIO;
+
+ return bL_cpufreq_register(&scpi_cpufreq_ops);
+}
+
+static int scpi_cpufreq_remove(struct platform_device *pdev)
+{
+ bL_cpufreq_unregister(&scpi_cpufreq_ops);
+ scpi_ops = NULL;
+ return 0;
+}
+
+static struct platform_driver scpi_cpufreq_platdrv = {
+ .driver = {
+ .name = "scpi-cpufreq",
+ .owner = THIS_MODULE,
+ },
+ .probe = scpi_cpufreq_probe,
+ .remove = scpi_cpufreq_remove,
+};
+module_platform_driver(scpi_cpufreq_platdrv);
+
+MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
+MODULE_LICENSE("GPL v2");