From 31027c244478bec914b26ac70700b2e750e17dfc Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Thu, 8 May 2014 17:47:48 +0100 Subject: 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 Signed-off-by: Jon Medhurst --- drivers/cpufreq/Kconfig.arm | 9 ++++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/scpi-cpufreq.c | 99 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 109 insertions(+) create mode 100644 drivers/cpufreq/scpi-cpufreq.c (limited to 'drivers/cpufreq') 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 + * + * 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 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"); -- cgit v1.2.3