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authorSudeep Holla <sudeep.holla@arm.com>2014-05-08 17:47:48 +0100
committerJon Medhurst <tixy@linaro.org>2015-03-16 12:00:34 +0000
commit31027c244478bec914b26ac70700b2e750e17dfc (patch)
tree9b2e6d819b13e6925836eb5b4f8c53976aaa580d /drivers
parent2aef174fefdf7bfa97942a02621aeb9642fc2207 (diff)
downloadlinux-31027c244478bec914b26ac70700b2e750e17dfc.tar.gz
cpufreq: arm_big_little: add SPCI 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> Signed-off-by: Jon Medhurst <tixy@linaro.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/cpufreq/Kconfig.arm9
-rw-r--r--drivers/cpufreq/Makefile1
-rw-r--r--drivers/cpufreq/scpi-cpufreq.c99
3 files changed, 109 insertions, 0 deletions
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 1b06fc4640e2..1d31eb655e1e 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_SPCI_CPUFREQ
+ tristate "SPCI based CPUfreq driver"
+ depends on ARM_BIG_LITTLE_CPUFREQ && ARM_SCPI_PROTOCOL
+ help
+ This add the CPUfreq driver support for ARM big.LITTLE platforms
+ using SCPI interface for CPU power management.
+
+ This driver works only if firmware the supporting CPU DVFS adhere
+ to SCPI protocol.
config ARM_EXYNOS_CPUFREQ
tristate "SAMSUNG EXYNOS CPUfreq Driver"
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 82a1821471fd..d5bb7e16ba48 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -78,6 +78,7 @@ 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_SPCI_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..60725199b9aa
--- /dev/null
+++ b/drivers/cpufreq/scpi-cpufreq.c
@@ -0,0 +1,99 @@
+/*
+ * SCPI CPUFreq Interface driver
+ *
+ * It provides necessary ops to arm_big_little cpufreq driver.
+ *
+ * Copyright (C) 2014 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 int scpi_init_opp_table(struct device *cpu_dev)
+{
+ u8 domain = topology_physical_package_id(cpu_dev->id);
+ struct scpi_opp *opp;
+ int idx, ret = 0, max_opp;
+ u32 *freqs;
+
+ opp = scpi_dvfs_get_opps(domain);
+ if (IS_ERR(opp))
+ return PTR_ERR(opp);
+
+ freqs = opp->freqs;
+ max_opp = opp->count;
+ for (idx = 0; idx < max_opp; idx++, freqs++) {
+ ret = dev_pm_opp_add(cpu_dev, *freqs, 900000000 /* TODO */);
+ if (ret) {
+ dev_warn(cpu_dev, "failed to add opp %u\n", *freqs);
+ return ret;
+ }
+ }
+ return ret;
+}
+
+static int scpi_get_transition_latency(struct device *cpu_dev)
+{
+ u8 domain = topology_physical_package_id(cpu_dev->id);
+ struct scpi_opp *opp;
+
+ opp = scpi_dvfs_get_opps(domain);
+ if (IS_ERR(opp))
+ return PTR_ERR(opp);
+
+ return opp->latency * 1000; /* SCPI returns in uS */
+}
+
+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,
+};
+
+static int scpi_cpufreq_probe(struct platform_device *pdev)
+{
+ return bL_cpufreq_register(&scpi_cpufreq_ops);
+}
+
+static int scpi_cpufreq_remove(struct platform_device *pdev)
+{
+ bL_cpufreq_unregister(&scpi_cpufreq_ops);
+ return 0;
+}
+
+static struct of_device_id scpi_cpufreq_of_match[] = {
+ { .compatible = "arm,scpi-cpufreq" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, scpi_cpufreq_of_match);
+
+static struct platform_driver scpi_cpufreq_platdrv = {
+ .driver = {
+ .name = "scpi-cpufreq",
+ .owner = THIS_MODULE,
+ .of_match_table = scpi_cpufreq_of_match,
+ },
+ .probe = scpi_cpufreq_probe,
+ .remove = scpi_cpufreq_remove,
+};
+module_platform_driver(scpi_cpufreq_platdrv);
+
+MODULE_LICENSE("GPL");