This driver utilizes the methods introduced in the previous patch - "ACPI: Introduce CPU performance controls using CPPC" and enables usage with existing CPUFreq governors.
Signed-off-by: Ashwin Chaugule ashwin.chaugule@linaro.org Reviewed-by: Al Stone al.stone@linaro.org --- drivers/cpufreq/Kconfig.arm | 16 ++++ drivers/cpufreq/Makefile | 2 + drivers/cpufreq/cppc_cpufreq.c | 197 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 215 insertions(+) create mode 100644 drivers/cpufreq/cppc_cpufreq.c
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index 4f3dbc8..c45f389 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -272,3 +272,19 @@ config ARM_PXA2xx_CPUFREQ This add the CPUFreq driver support for Intel PXA2xx SOCs.
If in doubt, say N. + +config ACPI_CPPC_CPUFREQ + tristate "CPUFreq driver based on the ACPI CPPC spec" + depends on ACPI_CPPC + default n + help + This adds a CPUFreq driver which uses CPPC methods + as described in the ACPIv5.1 spec. CPPC stands for + Collaborative Processor Performance Controls. It + is based on an abstract continuous scale of CPU + performance values which allows the remote power + processor to flexibly optimize for power and + performance. CPPC relies on power management firmware + for its operation. + + If in doubt, say N. diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index cdce92a..ef3779b 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -79,6 +79,8 @@ 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_ACPI_CPPC_CPUFREQ) += cppc_cpufreq.o +
################################################################################## # PowerPC platform drivers diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c new file mode 100644 index 0000000..b5af4c8 --- /dev/null +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -0,0 +1,197 @@ +/* + * CPPC (Collaborative Processor Performance Control) driver for + * interfacing with the CPUfreq layer and governors. See + * cppc_acpi.c for CPPC specific methods. + * + * (C) Copyright 2014 Linaro Ltd. + * Author: Ashwin Chaugule ashwin.chaugule@linaro.org + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ + +#define pr_fmt(fmt) "CPPC Cpufreq:" fmt + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/cpu.h> +#include <linux/cpufreq.h> +#include <linux/vmalloc.h> + +#include <acpi/cppc_acpi.h> + +static struct cpudata **all_cpu_data; + +static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + struct cpudata *cpu; + struct cpufreq_freqs freqs; + int ret; + + cpu = all_cpu_data[policy->cpu]; + + cpu->perf_ctrls.desired_perf = target_freq; + freqs.old = policy->cur; + freqs.new = target_freq; + + cpufreq_freq_transition_begin(policy, &freqs); + ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls); + cpufreq_freq_transition_end(policy, &freqs, ret != 0); + + if (ret) { + pr_debug("Failed to set target on CPU:%d. ret:%d\n", + cpu->cpu, ret); + return -EINVAL; + } + + return 0; +} + +static unsigned int cppc_cpufreq_get_perf(unsigned int cpu_num) +{ + struct cpudata *cpu; + int32_t delivered_perf = 1; + int ret; + + cpu = all_cpu_data[cpu_num]; + if (!cpu) + return 0; + + ret = cppc_get_perf_ctrs(cpu_num, &cpu->perf_fb_ctrs); + + if (ret) { + pr_err("Err reading CPU%d, perf counters. ret:%d\n", + cpu->cpu, ret); + return -ENODEV; + } + delivered_perf = cpu->perf_caps.reference_perf * + cpu->perf_fb_ctrs.delivered; + delivered_perf /= cpu->perf_fb_ctrs.reference; + pr_debug("delivered_perf: %d\n", delivered_perf); + pr_debug("reference_perf: %d\n", + cpu->perf_caps.reference_perf); + pr_debug("delivered, reference deltas: %lld, %lld\n", + cpu->perf_fb_ctrs.delivered, + cpu->perf_fb_ctrs.reference); + + return delivered_perf; +} + +static int cppc_verify_policy(struct cpufreq_policy *policy) +{ + cpufreq_verify_within_cpu_limits(policy); + return 0; +} + +static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy) +{ + int cpu_num = policy->cpu; + struct cpudata *cpu = all_cpu_data[cpu_num]; + int ret; + + pr_info("CPU %d exiting\n", cpu_num); + + cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf; + + ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); + if (ret) + pr_err("Err setting perf value:%d on CPU:%d. ret:%d\n", + cpu->perf_caps.lowest_perf, cpu_num, ret); +} + +static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) +{ + struct cpudata *cpu; + int ret; + + cpu = all_cpu_data[policy->cpu]; + + cpu->cpu = policy->cpu; + ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps); + + if (ret) { + pr_err("Err reading CPU%d, perf capabilities. ret:%d\n", + cpu->cpu, ret); + return -ENODEV; + } + + policy->min = cpu->perf_caps.lowest_perf; + policy->max = cpu->perf_caps.highest_perf; + /* cpuinfo and default policy values */ + policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf; + policy->cpuinfo.max_freq = cpu->perf_caps.highest_perf; + + if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL || + policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) + cpumask_copy(policy->cpus, cpu->shared_cpu_map); + + cpumask_set_cpu(policy->cpu, policy->cpus); + cpu->cur_policy = policy; + + pr_info("Initialized on cpu:%d\n", cpu->cpu); + return 0; +} + +static struct cpufreq_driver cppc_cpufreq_driver = { + .flags = CPUFREQ_CONST_LOOPS, + .verify = cppc_verify_policy, + .target = cppc_cpufreq_set_target, + .get = cppc_cpufreq_get_perf, + .init = cppc_cpufreq_cpu_init, + .stop_cpu = cppc_cpufreq_stop_cpu, + .name = "cppc_cpufreq", +}; + +static int __init cppc_cpufreq_init(void) +{ + int i, rc = 0; + struct cpudata *cpu; + + if (acpi_disabled) + return -ENODEV; + + all_cpu_data = vzalloc(sizeof(void *) * num_possible_cpus()); + if (!all_cpu_data) + return -ENOMEM; + + for_each_possible_cpu(i) { + all_cpu_data[i] = kzalloc(sizeof(struct cpudata), GFP_KERNEL); + if (!all_cpu_data[i]) + goto out; + + cpu = all_cpu_data[i]; + if (!zalloc_cpumask_var(&cpu->shared_cpu_map, + GFP_KERNEL)) { + pr_debug("No memory for shared_cpus cpumask\n"); + goto out; + } + } + + rc = acpi_get_psd_map(all_cpu_data); + if (rc) { + pr_err("Error parsing PSD data\n"); + goto out; + } + + rc = cpufreq_register_driver(&cppc_cpufreq_driver); + if (rc) + goto out; + + pr_info("Registration completed\n"); + return rc; + +out: + for_each_possible_cpu(i) + if (all_cpu_data[i]) + kfree(all_cpu_data[i]); + + vfree(all_cpu_data); + return -ENODEV; +} + +late_initcall(cppc_cpufreq_init);