diff options
Diffstat (limited to 'drivers/cpufreq/cppc_cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/cppc_cpufreq.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c new file mode 100644 index 000000000..7c0bdfb1a --- /dev/null +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -0,0 +1,176 @@ +/* + * 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, 2015 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> + +/* + * These structs contain information parsed from per CPU + * ACPI _CPC structures. + * e.g. For each CPU the highest, lowest supported + * performance capabilities, desired performance level + * requested etc. + */ +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 = 0; + + 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 ret; +} + +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; + + cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf; + + ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); + if (ret) + pr_debug("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; + unsigned int cpu_num = policy->cpu; + int ret = 0; + + cpu = all_cpu_data[policy->cpu]; + + cpu->cpu = cpu_num; + ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps); + + if (ret) { + pr_debug("Err reading CPU%d perf capabilities. ret:%d\n", + cpu_num, ret); + return ret; + } + + policy->min = cpu->perf_caps.lowest_perf; + policy->max = cpu->perf_caps.highest_perf; + policy->cpuinfo.min_freq = policy->min; + policy->cpuinfo.max_freq = policy->max; + policy->shared_type = cpu->shared_type; + + if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) + cpumask_copy(policy->cpus, cpu->shared_cpu_map); + else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) { + /* Support only SW_ANY for now. */ + pr_debug("Unsupported CPU co-ord type\n"); + return -EFAULT; + } + + cpumask_set_cpu(policy->cpu, policy->cpus); + cpu->cur_policy = policy; + + /* Set policy->cur to max now. The governors will adjust later. */ + policy->cur = cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf; + + ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); + if (ret) + pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n", + cpu->perf_caps.highest_perf, cpu_num, ret); + + return ret; +} + +static struct cpufreq_driver cppc_cpufreq_driver = { + .flags = CPUFREQ_CONST_LOOPS, + .verify = cppc_verify_policy, + .target = cppc_cpufreq_set_target, + .init = cppc_cpufreq_cpu_init, + .stop_cpu = cppc_cpufreq_stop_cpu, + .name = "cppc_cpufreq", +}; + +static int __init cppc_cpufreq_init(void) +{ + int i, ret = 0; + struct cpudata *cpu; + + if (acpi_disabled) + return -ENODEV; + + all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL); + 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)) + goto out; + } + + ret = acpi_get_psd_map(all_cpu_data); + if (ret) { + pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n"); + goto out; + } + + ret = cpufreq_register_driver(&cppc_cpufreq_driver); + if (ret) + goto out; + + return ret; + +out: + for_each_possible_cpu(i) + kfree(all_cpu_data[i]); + + kfree(all_cpu_data); + return -ENODEV; +} + +late_initcall(cppc_cpufreq_init); |