blob: 173ed059d95f5fa2d46093d69b7912d1074df3de [file] [log] [blame]
Viresh Kumar8a67f0e2013-04-01 12:57:49 +00001/*
2 * Generic big.LITTLE CPUFreq Interface driver
3 *
4 * It provides necessary ops to arm_big_little cpufreq driver and gets
5 * Frequency information from Device Tree. Freq table in DT must be in KHz.
6 *
7 * Copyright (C) 2013 Linaro.
8 * Viresh Kumar <viresh.kumar@linaro.org>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 *
14 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
15 * kind, whether express or implied; without even the implied warranty
16 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 */
19
20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22#include <linux/cpufreq.h>
23#include <linux/device.h>
24#include <linux/export.h>
25#include <linux/module.h>
26#include <linux/of.h>
27#include <linux/opp.h>
28#include <linux/slab.h>
29#include <linux/types.h>
30#include "arm_big_little.h"
31
32static int dt_init_opp_table(struct device *cpu_dev)
33{
Viresh Kumar763f8c32013-04-15 07:05:24 +000034 struct device_node *np, *parent;
Viresh Kumar8a67f0e2013-04-01 12:57:49 +000035 int count = 0, ret;
36
Viresh Kumar763f8c32013-04-15 07:05:24 +000037 parent = of_find_node_by_path("/cpus");
38 if (!parent) {
39 pr_err("failed to find OF /cpus\n");
40 return -ENOENT;
41 }
42
43 for_each_child_of_node(parent, np) {
Viresh Kumar8a67f0e2013-04-01 12:57:49 +000044 if (count++ != cpu_dev->id)
45 continue;
Viresh Kumar763f8c32013-04-15 07:05:24 +000046 if (!of_get_property(np, "operating-points", NULL)) {
47 ret = -ENODATA;
48 } else {
49 cpu_dev->of_node = np;
50 ret = of_init_opp_table(cpu_dev);
51 }
52 of_node_put(np);
53 of_node_put(parent);
Viresh Kumar8a67f0e2013-04-01 12:57:49 +000054
Viresh Kumar763f8c32013-04-15 07:05:24 +000055 return ret;
Viresh Kumar8a67f0e2013-04-01 12:57:49 +000056 }
57
58 return -ENODEV;
59}
60
61static int dt_get_transition_latency(struct device *cpu_dev)
62{
Viresh Kumar763f8c32013-04-15 07:05:24 +000063 struct device_node *np, *parent;
Viresh Kumar8a67f0e2013-04-01 12:57:49 +000064 u32 transition_latency = CPUFREQ_ETERNAL;
65 int count = 0;
66
Viresh Kumar763f8c32013-04-15 07:05:24 +000067 parent = of_find_node_by_path("/cpus");
68 if (!parent) {
Viresh Kumar3c792e02013-04-29 13:24:46 +000069 pr_info("Failed to find OF /cpus. Use CPUFREQ_ETERNAL transition latency\n");
70 return CPUFREQ_ETERNAL;
Viresh Kumar763f8c32013-04-15 07:05:24 +000071 }
72
73 for_each_child_of_node(parent, np) {
Viresh Kumar8a67f0e2013-04-01 12:57:49 +000074 if (count++ != cpu_dev->id)
75 continue;
76
77 of_property_read_u32(np, "clock-latency", &transition_latency);
Viresh Kumar763f8c32013-04-15 07:05:24 +000078 of_node_put(np);
79 of_node_put(parent);
80
Viresh Kumar996905f2013-04-29 13:24:45 +000081 return transition_latency;
Viresh Kumar8a67f0e2013-04-01 12:57:49 +000082 }
83
Viresh Kumar3c792e02013-04-29 13:24:46 +000084 pr_info("clock-latency isn't found, use CPUFREQ_ETERNAL transition latency\n");
85 return CPUFREQ_ETERNAL;
Viresh Kumar8a67f0e2013-04-01 12:57:49 +000086}
87
88static struct cpufreq_arm_bL_ops dt_bL_ops = {
89 .name = "dt-bl",
90 .get_transition_latency = dt_get_transition_latency,
91 .init_opp_table = dt_init_opp_table,
92};
93
94static int generic_bL_init(void)
95{
96 return bL_cpufreq_register(&dt_bL_ops);
97}
98module_init(generic_bL_init);
99
100static void generic_bL_exit(void)
101{
102 return bL_cpufreq_unregister(&dt_bL_ops);
103}
104module_exit(generic_bL_exit);
105
106MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
107MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT");
108MODULE_LICENSE("GPL");