/* * ARM big.LITTLE Platforms CPUFreq support * * Copyright (C) 2013 ARM Ltd. * Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com> * * Copyright (C) 2013 Linaro. * Viresh Kumar <viresh.kumar@linaro.org> * * 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/clk.h> #include <linux/cpu.h> #include <linux/cpufreq.h> #include <linux/cpumask.h> #include <linux/export.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of_platform.h> #include <linux/pm_opp.h> #include <linux/slab.h> #include <linux/topology.h> #include <linux/types.h> #include "arm_big_little.h" /* Currently we support only two clusters */ #define A15_CLUSTER 0 #define A7_CLUSTER 1 #define MAX_CLUSTERS 2 #ifdef CONFIG_BL_SWITCHER #include <asm/bL_switcher.h> static bool bL_switching_enabled; #define is_bL_switching_enabled() bL_switching_enabled #define set_switching_enabled(x) (bL_switching_enabled = (x)) #else #define is_bL_switching_enabled() false #define set_switching_enabled(x) do { } while (0) #define bL_switch_request(...) do { } while (0) #define bL_switcher_put_enabled() do { } while (0) #define bL_switcher_get_enabled() do { } while (0) #endif #define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq) #define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq) static struct cpufreq_arm_bL_ops *arm_bL_ops; static struct clk *clk[MAX_CLUSTERS]; static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1]; static atomic_t cluster_usage[MAX_CLUSTERS + 1]; static unsigned int clk_big_min; /* (Big) clock frequencies */ static unsigned int clk_little_max; /* Maximum clock frequency (Little) */ static DEFINE_PER_CPU(unsigned int, physical_cluster); static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq); static struct mutex cluster_lock[MAX_CLUSTERS]; static inline int raw_cpu_to_cluster(int cpu) { return topology_physical_package_id(cpu); } static inline int cpu_to_cluster(int cpu) { return is_bL_switching_enabled() ? MAX_CLUSTERS : raw_cpu_to_cluster(cpu); } static unsigned int find_cluster_maxfreq(int cluster) { int j; u32 max_freq = 0, cpu_freq; for_each_online_cpu(j) { cpu_freq = per_cpu(cpu_last_req_freq, j); if ((cluster == per_cpu(physical_cluster, j)) && (max_freq < cpu_freq)) max_freq = cpu_freq; } pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster, max_freq); return max_freq; } static unsigned int clk_get_cpu_rate(unsigned int cpu) { u32 cur_cluster = per_cpu(physical_cluster, cpu); u32 rate = clk_get_rate(clk[cur_cluster]) / 1000; /* For switcher we use virtual A7 clock rates */ if (is_bL_switching_enabled()) rate = VIRT_FREQ(cur_cluster, rate); pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu, cur_cluster, rate); return rate; } static unsigned int bL_cpufreq_get_rate(unsigned int cpu) { if (is_bL_switching_enabled()) { pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq, cpu)); return per_cpu(cpu_last_req_freq, cpu); } else { return clk_get_cpu_rate(cpu); } } static unsigned int bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate) { u32 new_rate, prev_rate; int ret; bool bLs = is_bL_switching_enabled(); mutex_lock(&cluster_lock[new_cluster]); if (bLs) { prev_rate = per_cpu(cpu_last_req_freq, cpu); per_cpu(cpu_last_req_freq, cpu) = rate; per_cpu(physical_cluster, cpu) = new_cluster; new_rate = find_cluster_maxfreq(new_cluster); new_rate = ACTUAL_FREQ(new_cluster, new_rate); } else { new_rate = rate; } pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n", __func__, cpu, old_cluster, new_cluster, new_rate); ret = clk_set_rate(clk[new_cluster], new_rate * 1000); if (!ret) { /* * FIXME: clk_set_rate hasn't returned an error here however it * may be that clk_change_rate failed due to hardware or * firmware issues and wasn't able to report that due to the * current design of the clk core layer. To work around this * problem we will read back the clock rate and check it is * correct. This needs to be removed once clk core is fixed. */ if (clk_get_rate(clk[new_cluster]) != new_rate * 1000) ret = -EIO; } if (WARN_ON(ret)) { pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret, new_cluster); if (bLs) { per_cpu(cpu_last_req_freq, cpu) = prev_rate; per_cpu(physical_cluster, cpu) = old_cluster; } mutex_unlock(&cluster_lock[new_cluster]); return ret; } mutex_unlock(&cluster_lock[new_cluster]); /* Recalc freq for old cluster when switching clusters */ if (old_cluster != new_cluster) { pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d\n", __func__, cpu, old_cluster, new_cluster); /* Switch cluster */ bL_switch_request(cpu, new_cluster); mutex_lock(&cluster_lock[old_cluster]); /* Set freq of old cluster if there are cpus left on it */ new_rate = find_cluster_maxfreq(old_cluster); new_rate = ACTUAL_FREQ(old_cluster, new_rate); if (new_rate) { pr_debug("%s: Updating rate of old cluster: %d, to freq: %d\n", __func__, old_cluster, new_rate); if (clk_set_rate(clk[old_cluster], new_rate * 1000)) pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n", __func__, ret, old_cluster); } mutex_unlock(&cluster_lock[old_cluster]); } return 0; } /* Set clock frequency */ static int bL_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) { u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster; unsigned int freqs_new; cur_cluster = cpu_to_cluster(cpu); new_cluster = actual_cluster = per_cpu(physical_cluster, cpu); freqs_new = freq_table[cur_cluster][index].frequency; if (is_bL_switching_enabled()) { if ((actual_cluster == A15_CLUSTER) && (freqs_new < clk_big_min)) { new_cluster = A7_CLUSTER; } else if ((actual_cluster == A7_CLUSTER) && (freqs_new > clk_little_max)) { new_cluster = A15_CLUSTER; } } return bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs_new); } static inline u32 get_table_count(struct cpufreq_frequency_table *table) { int count; for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++) ; return count; } /* get the minimum frequency in the cpufreq_frequency_table */ static inline u32 get_table_min(struct cpufreq_frequency_table *table) { struct cpufreq_frequency_table *pos; uint32_t min_freq = ~0; cpufreq_for_each_entry(pos, table) if (pos->frequency < min_freq) min_freq = pos->frequency; return min_freq; } /* get the maximum frequency in the cpufreq_frequency_table */ static inline u32 get_table_max(struct cpufreq_frequency_table *table) { struct cpufreq_frequency_table *pos; uint32_t max_freq = 0; cpufreq_for_each_entry(pos, table) if (pos->frequency > max_freq) max_freq = pos->frequency; return max_freq; } static int merge_cluster_tables(void) { int i, j, k = 0, count = 1; struct cpufreq_frequency_table *table; for (i = 0; i < MAX_CLUSTERS; i++) count += get_table_count(freq_table[i]); table = kzalloc(sizeof(*table) * count, GFP_KERNEL); if (!table) return -ENOMEM; freq_table[MAX_CLUSTERS] = table; /* Add in reverse order to get freqs in increasing order */ for (i = MAX_CLUSTERS - 1; i >= 0; i--) { for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END; j++) { table[k].frequency = VIRT_FREQ(i, freq_table[i][j].frequency); pr_debug("%s: index: %d, freq: %d\n", __func__, k, table[k].frequency); k++; } } table[k].driver_data = k; table[k].frequency = CPUFREQ_TABLE_END; pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k); return 0; } static void _put_cluster_clk_and_freq_table(struct device *cpu_dev) { u32 cluster = raw_cpu_to_cluster(cpu_dev->id); if (!freq_table[cluster]) return; clk_put(clk[cluster]); dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]); if (arm_bL_ops->free_opp_table) arm_bL_ops->free_opp_table(cpu_dev); dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster); } static void put_cluster_clk_and_freq_table(struct device *cpu_dev) { u32 cluster = cpu_to_cluster(cpu_dev->id); int i; if (atomic_dec_return(&cluster_usage[cluster])) return; if (cluster < MAX_CLUSTERS) return _put_cluster_clk_and_freq_table(cpu_dev); for_each_present_cpu(i) { struct device *cdev = get_cpu_device(i); if (!cdev) { pr_err("%s: failed to get cpu%d device\n", __func__, i); return; } _put_cluster_clk_and_freq_table(cdev); } /* free virtual table */ kfree(freq_table[cluster]); } static int _get_cluster_clk_and_freq_table(struct device *cpu_dev) { u32 cluster = raw_cpu_to_cluster(cpu_dev->id); int ret; if (freq_table[cluster]) return 0; ret = arm_bL_ops->init_opp_table(cpu_dev); if (ret) { dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n", __func__, cpu_dev->id, ret); goto out; } ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]); if (ret) { dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n", __func__, cpu_dev->id, ret); goto free_opp_table; } clk[cluster] = clk_get(cpu_dev, NULL); if (!IS_ERR(clk[cluster])) { dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n", __func__, clk[cluster], freq_table[cluster], cluster); return 0; } dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n", __func__, cpu_dev->id, cluster); ret = PTR_ERR(clk[cluster]); dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]); free_opp_table: if (arm_bL_ops->free_opp_table) arm_bL_ops->free_opp_table(cpu_dev); out: dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__, cluster); return ret; } static int get_cluster_clk_and_freq_table(struct device *cpu_dev) { u32 cluster = cpu_to_cluster(cpu_dev->id); int i, ret; if (atomic_inc_return(&cluster_usage[cluster]) != 1) return 0; if (cluster < MAX_CLUSTERS) { ret = _get_cluster_clk_and_freq_table(cpu_dev); if (ret) atomic_dec(&cluster_usage[cluster]); return ret; } /* * Get data for all clusters and fill virtual cluster with a merge of * both */ for_each_present_cpu(i) { struct device *cdev = get_cpu_device(i); if (!cdev) { pr_err("%s: failed to get cpu%d device\n", __func__, i); return -ENODEV; } ret = _get_cluster_clk_and_freq_table(cdev); if (ret) goto put_clusters; } ret = merge_cluster_tables(); if (ret) goto put_clusters; /* Assuming 2 cluster, set clk_big_min and clk_little_max */ clk_big_min = get_table_min(freq_table[0]); clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1])); pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n", __func__, cluster, clk_big_min, clk_little_max); return 0; put_clusters: for_each_present_cpu(i) { struct device *cdev = get_cpu_device(i); if (!cdev) { pr_err("%s: failed to get cpu%d device\n", __func__, i); return -ENODEV; } _put_cluster_clk_and_freq_table(cdev); } atomic_dec(&cluster_usage[cluster]); return ret; } /* Per-CPU initialization */ static int bL_cpufreq_init(struct cpufreq_policy *policy) { u32 cur_cluster = cpu_to_cluster(policy->cpu); struct device *cpu_dev; int ret; cpu_dev = get_cpu_device(policy->cpu); if (!cpu_dev) { pr_err("%s: failed to get cpu%d device\n", __func__, policy->cpu); return -ENODEV; } ret = get_cluster_clk_and_freq_table(cpu_dev); if (ret) return ret; ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]); if (ret) { dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n", policy->cpu, cur_cluster); put_cluster_clk_and_freq_table(cpu_dev); return ret; } if (cur_cluster < MAX_CLUSTERS) { int cpu; cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu)); for_each_cpu(cpu, policy->cpus) per_cpu(physical_cluster, cpu) = cur_cluster; } else { /* Assumption: during init, we are always running on A15 */ per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER; } if (arm_bL_ops->get_transition_latency) policy->cpuinfo.transition_latency = arm_bL_ops->get_transition_latency(cpu_dev); else policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; if (is_bL_switching_enabled()) per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(policy->cpu); dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu); return 0; } static int bL_cpufreq_exit(struct cpufreq_policy *policy) { struct device *cpu_dev; cpu_dev = get_cpu_device(policy->cpu); if (!cpu_dev) { pr_err("%s: failed to get cpu%d device\n", __func__, policy->cpu); return -ENODEV; } put_cluster_clk_and_freq_table(cpu_dev); dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu); return 0; } static struct cpufreq_driver bL_cpufreq_driver = { .name = "arm-big-little", .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, .verify = cpufreq_generic_frequency_table_verify, .target_index = bL_cpufreq_set_target, .get = bL_cpufreq_get_rate, .init = bL_cpufreq_init, .exit = bL_cpufreq_exit, .attr = cpufreq_generic_attr, }; #ifdef CONFIG_BL_SWITCHER static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb, unsigned long action, void *_arg) { pr_debug("%s: action: %ld\n", __func__, action); switch (action) { case BL_NOTIFY_PRE_ENABLE: case BL_NOTIFY_PRE_DISABLE: cpufreq_unregister_driver(&bL_cpufreq_driver); break; case BL_NOTIFY_POST_ENABLE: set_switching_enabled(true); cpufreq_register_driver(&bL_cpufreq_driver); break; case BL_NOTIFY_POST_DISABLE: set_switching_enabled(false); cpufreq_register_driver(&bL_cpufreq_driver); break; default: return NOTIFY_DONE; } return NOTIFY_OK; } static struct notifier_block bL_switcher_notifier = { .notifier_call = bL_cpufreq_switcher_notifier, }; static int __bLs_register_notifier(void) { return bL_switcher_register_notifier(&bL_switcher_notifier); } static int __bLs_unregister_notifier(void) { return bL_switcher_unregister_notifier(&bL_switcher_notifier); } #else static int __bLs_register_notifier(void) { return 0; } static int __bLs_unregister_notifier(void) { return 0; } #endif int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops) { int ret, i; if (arm_bL_ops) { pr_debug("%s: Already registered: %s, exiting\n", __func__, arm_bL_ops->name); return -EBUSY; } if (!ops || !strlen(ops->name) || !ops->init_opp_table) { pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__); return -ENODEV; } arm_bL_ops = ops; set_switching_enabled(bL_switcher_get_enabled()); for (i = 0; i < MAX_CLUSTERS; i++) mutex_init(&cluster_lock[i]); ret = cpufreq_register_driver(&bL_cpufreq_driver); if (ret) { pr_info("%s: Failed registering platform driver: %s, err: %d\n", __func__, ops->name, ret); arm_bL_ops = NULL; } else { ret = __bLs_register_notifier(); if (ret) { cpufreq_unregister_driver(&bL_cpufreq_driver); arm_bL_ops = NULL; } else { pr_info("%s: Registered platform driver: %s\n", __func__, ops->name); } } bL_switcher_put_enabled(); return ret; } EXPORT_SYMBOL_GPL(bL_cpufreq_register); void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops) { if (arm_bL_ops != ops) { pr_err("%s: Registered with: %s, can't unregister, exiting\n", __func__, arm_bL_ops->name); return; } bL_switcher_get_enabled(); __bLs_unregister_notifier(); cpufreq_unregister_driver(&bL_cpufreq_driver); bL_switcher_put_enabled(); pr_info("%s: Un-registered platform driver: %s\n", __func__, arm_bL_ops->name); arm_bL_ops = NULL; } EXPORT_SYMBOL_GPL(bL_cpufreq_unregister); MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver"); MODULE_LICENSE("GPL v2");