From 8def31034d033961a4e1f34a80f317fd7002faee Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Mon, 30 Mar 2015 10:59:52 +0100 Subject: [PATCH] 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 Acked-by: Viresh Kumar Cc: "Rafael J. Wysocki" Cc: linux-pm@vger.kernel.org --- MAINTAINERS | 1 + drivers/cpufreq/Kconfig.arm | 10 +++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/scpi-cpufreq.c | 124 +++++++++++++++++++++++++++++++++ 4 files changed, 136 insertions(+) create mode 100644 drivers/cpufreq/scpi-cpufreq.c diff --git a/MAINTAINERS b/MAINTAINERS index 613a116ab0f4..e39ae88cf423 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9155,6 +9155,7 @@ 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 cd0391e46c6d..c737f7359974 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -199,6 +199,16 @@ config ARM_SA1100_CPUFREQ config ARM_SA1110_CPUFREQ bool +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_SPEAR_CPUFREQ bool "SPEAr CPUFreq support" depends on PLAT_SPEAR diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index 41340384f11f..ccfaa4c68a9a 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -72,6 +72,7 @@ obj-$(CONFIG_ARM_S3C64XX_CPUFREQ) += s3c64xx-cpufreq.o obj-$(CONFIG_ARM_S5PV210_CPUFREQ) += s5pv210-cpufreq.o obj-$(CONFIG_ARM_SA1100_CPUFREQ) += sa1100-cpufreq.o obj-$(CONFIG_ARM_SA1110_CPUFREQ) += sa1110-cpufreq.o +obj-$(CONFIG_ARM_SCPI_CPUFREQ) += scpi-cpufreq.o obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o obj-$(CONFIG_ARM_TEGRA20_CPUFREQ) += tegra20-cpufreq.o obj-$(CONFIG_ARM_TEGRA124_CPUFREQ) += tegra124-cpufreq.o 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 + * + * 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 +#include +#include +#include +#include +#include + +#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 "); +MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver"); +MODULE_LICENSE("GPL v2");