1 files changed, 124 insertions, 0 deletions
diff --git a/kernel/sched/energy.c b/kernel/sched/energy.c
new file mode 100644
index 000000000000..b0656b7a93e3
--- /dev/null
+++ b/kernel/sched/energy.c
@@ -0,0 +1,124 @@
+/*
+ * Obtain energy cost data from DT and populate relevant scheduler data
+ * structures.
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ *
+ * 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 in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#define pr_fmt(fmt) "sched-energy: " fmt
+
+#define DEBUG
+
+#include <linux/gfp.h>
+#include <linux/of.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/sched_energy.h>
+#include <linux/stddef.h>
+
+struct sched_group_energy *sge_array[NR_CPUS][NR_SD_LEVELS];
+
+static void free_resources(void)
+{
+	int cpu, sd_level;
+	struct sched_group_energy *sge;
+
+	for_each_possible_cpu(cpu) {
+		for_each_possible_sd_level(sd_level) {
+			sge = sge_array[cpu][sd_level];
+			if (sge) {
+				kfree(sge->cap_states);
+				kfree(sge->idle_states);
+				kfree(sge);
+			}
+		}
+	}
+}
+
+void init_sched_energy_costs(void)
+{
+	struct device_node *cn, *cp;
+	struct capacity_state *cap_states;
+	struct idle_state *idle_states;
+	struct sched_group_energy *sge;
+	const struct property *prop;
+	int sd_level, i, nstates, cpu;
+	const __be32 *val;
+
+	for_each_possible_cpu(cpu) {
+		cn = of_get_cpu_node(cpu, NULL);
+		if (!cn) {
+			pr_warn("CPU device node missing for CPU %d\n", cpu);
+			return;
+		}
+
+		if (!of_find_property(cn, "sched-energy-costs", NULL)) {
+			pr_warn("CPU device node has no sched-energy-costs\n");
+			return;
+		}
+
+		for_each_possible_sd_level(sd_level) {
+			cp = of_parse_phandle(cn, "sched-energy-costs", sd_level);
+			if (!cp)
+				break;
+
+			prop = of_find_property(cp, "busy-cost-data", NULL);
+			if (!prop || !prop->value) {
+				pr_warn("No busy-cost data, skipping sched_energy init\n");
+				goto out;
+			}
+
+			sge = kcalloc(1, sizeof(struct sched_group_energy),
+				      GFP_NOWAIT);
+
+			nstates = (prop->length / sizeof(u32)) / 2;
+			cap_states = kcalloc(nstates,
+					     sizeof(struct capacity_state),
+					     GFP_NOWAIT);
+
+			for (i = 0, val = prop->value; i < nstates; i++) {
+				cap_states[i].cap = be32_to_cpup(val++);
+				cap_states[i].power = be32_to_cpup(val++);
+			}
+
+			sge->nr_cap_states = nstates;
+			sge->cap_states = cap_states;
+
+			prop = of_find_property(cp, "idle-cost-data", NULL);
+			if (!prop || !prop->value) {
+				pr_warn("No idle-cost data, skipping sched_energy init\n");
+				goto out;
+			}
+
+			nstates = (prop->length / sizeof(u32));
+			idle_states = kcalloc(nstates,
+					      sizeof(struct idle_state),
+					      GFP_NOWAIT);
+
+			for (i = 0, val = prop->value; i < nstates; i++)
+				idle_states[i].power = be32_to_cpup(val++);
+
+			sge->nr_idle_states = nstates;
+			sge->idle_states = idle_states;
+
+			sge_array[cpu][sd_level] = sge;
+		}
+	}
+
+	pr_info("Sched-energy-costs installed from DT\n");
+	return;
+
+out:
+	free_resources();
+}