Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH v2 5/5] cpufreq: arm_big_little: add SCPI interface driver | Date | Fri, 15 May 2015 00:03:12 +0200 |
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On Thursday, May 14, 2015 04:42:35 PM Sudeep Holla wrote: > 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> > Cc: Viresh Kumar <viresh.kumar@linaro.org> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > Cc: linux-pm@vger.kernel.org > --- > drivers/cpufreq/Kconfig.arm | 9 +++ > drivers/cpufreq/Makefile | 1 + > drivers/cpufreq/scpi-cpufreq.c | 124 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 134 insertions(+) > create mode 100644 drivers/cpufreq/scpi-cpufreq.c > > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm > index 611cb09239eb..6419b17b89dd 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 > tristate "SAMSUNG EXYNOS CPUfreq Driver" > diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile > index cdce92ae2e8b..02fc9f849d4b 100644 > --- a/drivers/cpufreq/Makefile > +++ b/drivers/cpufreq/Makefile > @@ -79,6 +79,7 @@ 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..443570801229 > --- /dev/null > +++ b/drivers/cpufreq/scpi-cpufreq.c > @@ -0,0 +1,124 @@ > +/* > + * SCPI CPUFreq Interface driver
It would be good to expand the TLA here IMO.
The rest I'm leaving to Viresh. :-)
> + * > + * 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"); >
-- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.
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