Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
new file mode 100644
index 0000000..0a9326f
--- /dev/null
+++ b/kernel/power/energy_model.c
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Energy Model of CPUs
+ *
+ * Copyright (c) 2018, Arm ltd.
+ * Written by: Quentin Perret, Arm ltd.
+ */
+
+#define pr_fmt(fmt) "energy_model: " fmt
+
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/debugfs.h>
+#include <linux/energy_model.h>
+#include <linux/sched/topology.h>
+#include <linux/slab.h>
+
+/* Mapping of each CPU to the performance domain to which it belongs. */
+static DEFINE_PER_CPU(struct em_perf_domain *, em_data);
+
+/*
+ * Mutex serializing the registrations of performance domains and letting
+ * callbacks defined by drivers sleep.
+ */
+static DEFINE_MUTEX(em_pd_mutex);
+
+#ifdef CONFIG_DEBUG_FS
+static struct dentry *rootdir;
+
+static void em_debug_create_cs(struct em_cap_state *cs, struct dentry *pd)
+{
+ struct dentry *d;
+ char name[24];
+
+ snprintf(name, sizeof(name), "cs:%lu", cs->frequency);
+
+ /* Create per-cs directory */
+ d = debugfs_create_dir(name, pd);
+ debugfs_create_ulong("frequency", 0444, d, &cs->frequency);
+ debugfs_create_ulong("power", 0444, d, &cs->power);
+ debugfs_create_ulong("cost", 0444, d, &cs->cost);
+}
+
+static int em_debug_cpus_show(struct seq_file *s, void *unused)
+{
+ seq_printf(s, "%*pbl\n", cpumask_pr_args(to_cpumask(s->private)));
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);
+
+static void em_debug_create_pd(struct em_perf_domain *pd, int cpu)
+{
+ struct dentry *d;
+ char name[8];
+ int i;
+
+ snprintf(name, sizeof(name), "pd%d", cpu);
+
+ /* Create the directory of the performance domain */
+ d = debugfs_create_dir(name, rootdir);
+
+ debugfs_create_file("cpus", 0444, d, pd->cpus, &em_debug_cpus_fops);
+
+ /* Create a sub-directory for each capacity state */
+ for (i = 0; i < pd->nr_cap_states; i++)
+ em_debug_create_cs(&pd->table[i], d);
+}
+
+static int __init em_debug_init(void)
+{
+ /* Create /sys/kernel/debug/energy_model directory */
+ rootdir = debugfs_create_dir("energy_model", NULL);
+
+ return 0;
+}
+core_initcall(em_debug_init);
+#else /* CONFIG_DEBUG_FS */
+static void em_debug_create_pd(struct em_perf_domain *pd, int cpu) {}
+#endif
+static struct em_perf_domain *em_create_pd(cpumask_t *span, int nr_states,
+ struct em_data_callback *cb)
+{
+ unsigned long opp_eff, prev_opp_eff = ULONG_MAX;
+ unsigned long power, freq, prev_freq = 0;
+ int i, ret, cpu = cpumask_first(span);
+ struct em_cap_state *table;
+ struct em_perf_domain *pd;
+ u64 fmax;
+
+ if (!cb->active_power)
+ return NULL;
+
+ pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL);
+ if (!pd)
+ return NULL;
+
+ table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL);
+ if (!table)
+ goto free_pd;
+
+ /* Build the list of capacity states for this performance domain */
+ for (i = 0, freq = 0; i < nr_states; i++, freq++) {
+ /*
+ * active_power() is a driver callback which ceils 'freq' to
+ * lowest capacity state of 'cpu' above 'freq' and updates
+ * 'power' and 'freq' accordingly.
+ */
+ ret = cb->active_power(&power, &freq, cpu);
+ if (ret) {
+ pr_err("pd%d: invalid cap. state: %d\n", cpu, ret);
+ goto free_cs_table;
+ }
+
+ /*
+ * We expect the driver callback to increase the frequency for
+ * higher capacity states.
+ */
+ if (freq <= prev_freq) {
+ pr_err("pd%d: non-increasing freq: %lu\n", cpu, freq);
+ goto free_cs_table;
+ }
+
+ /*
+ * The power returned by active_state() is expected to be
+ * positive, in milli-watts and to fit into 16 bits.
+ */
+ if (!power || power > EM_CPU_MAX_POWER) {
+ pr_err("pd%d: invalid power: %lu\n", cpu, power);
+ goto free_cs_table;
+ }
+
+ table[i].power = power;
+ table[i].frequency = prev_freq = freq;
+
+ /*
+ * The hertz/watts efficiency ratio should decrease as the
+ * frequency grows on sane platforms. But this isn't always
+ * true in practice so warn the user if a higher OPP is more
+ * power efficient than a lower one.
+ */
+ opp_eff = freq / power;
+ if (opp_eff >= prev_opp_eff)
+ pr_warn("pd%d: hertz/watts ratio non-monotonically decreasing: em_cap_state %d >= em_cap_state%d\n",
+ cpu, i, i - 1);
+ prev_opp_eff = opp_eff;
+ }
+
+ /* Compute the cost of each capacity_state. */
+ fmax = (u64) table[nr_states - 1].frequency;
+ for (i = 0; i < nr_states; i++) {
+ table[i].cost = div64_u64(fmax * table[i].power,
+ table[i].frequency);
+ }
+
+ pd->table = table;
+ pd->nr_cap_states = nr_states;
+ cpumask_copy(to_cpumask(pd->cpus), span);
+
+ em_debug_create_pd(pd, cpu);
+
+ return pd;
+
+free_cs_table:
+ kfree(table);
+free_pd:
+ kfree(pd);
+
+ return NULL;
+}
+
+/**
+ * em_cpu_get() - Return the performance domain for a CPU
+ * @cpu : CPU to find the performance domain for
+ *
+ * Return: the performance domain to which 'cpu' belongs, or NULL if it doesn't
+ * exist.
+ */
+struct em_perf_domain *em_cpu_get(int cpu)
+{
+ return READ_ONCE(per_cpu(em_data, cpu));
+}
+EXPORT_SYMBOL_GPL(em_cpu_get);
+
+/**
+ * em_register_perf_domain() - Register the Energy Model of a performance domain
+ * @span : Mask of CPUs in the performance domain
+ * @nr_states : Number of capacity states to register
+ * @cb : Callback functions providing the data of the Energy Model
+ *
+ * Create Energy Model tables for a performance domain using the callbacks
+ * defined in cb.
+ *
+ * If multiple clients register the same performance domain, all but the first
+ * registration will be ignored.
+ *
+ * Return 0 on success
+ */
+int em_register_perf_domain(cpumask_t *span, unsigned int nr_states,
+ struct em_data_callback *cb)
+{
+ unsigned long cap, prev_cap = 0;
+ struct em_perf_domain *pd;
+ int cpu, ret = 0;
+
+ if (!span || !nr_states || !cb)
+ return -EINVAL;
+
+ /*
+ * Use a mutex to serialize the registration of performance domains and
+ * let the driver-defined callback functions sleep.
+ */
+ mutex_lock(&em_pd_mutex);
+
+ for_each_cpu(cpu, span) {
+ /* Make sure we don't register again an existing domain. */
+ if (READ_ONCE(per_cpu(em_data, cpu))) {
+ ret = -EEXIST;
+ goto unlock;
+ }
+
+ /*
+ * All CPUs of a domain must have the same micro-architecture
+ * since they all share the same table.
+ */
+ cap = arch_scale_cpu_capacity(cpu);
+ if (prev_cap && prev_cap != cap) {
+ pr_err("CPUs of %*pbl must have the same capacity\n",
+ cpumask_pr_args(span));
+ ret = -EINVAL;
+ goto unlock;
+ }
+ prev_cap = cap;
+ }
+
+ /* Create the performance domain and add it to the Energy Model. */
+ pd = em_create_pd(span, nr_states, cb);
+ if (!pd) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ for_each_cpu(cpu, span) {
+ /*
+ * The per-cpu array can be read concurrently from em_cpu_get().
+ * The barrier enforces the ordering needed to make sure readers
+ * can only access well formed em_perf_domain structs.
+ */
+ smp_store_release(per_cpu_ptr(&em_data, cpu), pd);
+ }
+
+ pr_debug("Created perf domain %*pbl\n", cpumask_pr_args(span));
+unlock:
+ mutex_unlock(&em_pd_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(em_register_perf_domain);