1 /*
2 * CPUFreq support for Armada 370/XP platforms.
3 *
4 * Copyright (C) 2012-2016 Marvell
5 *
6 * Yehuda Yitschak <yehuday@marvell.com>
7 * Gregory Clement <gregory.clement@free-electrons.com>
8 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
9 *
10 * This file is licensed under the terms of the GNU General Public
11 * License version 2. This program is licensed "as is" without any
12 * warranty of any kind, whether express or implied.
13 */
14
15 #define pr_fmt(fmt) "mvebu-pmsu: " fmt
16
17 #include <linux/clk.h>
18 #include <linux/cpu.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/of_address.h>
22 #include <linux/platform_device.h>
23 #include <linux/pm_opp.h>
24 #include <linux/resource.h>
25
armada_xp_pmsu_cpufreq_init(void)26 static int __init armada_xp_pmsu_cpufreq_init(void)
27 {
28 struct device_node *np;
29 struct resource res;
30 int ret, cpu;
31
32 if (!of_machine_is_compatible("marvell,armadaxp"))
33 return 0;
34
35 /*
36 * In order to have proper cpufreq handling, we need to ensure
37 * that the Device Tree description of the CPU clock includes
38 * the definition of the PMU DFS registers. If not, we do not
39 * register the clock notifier and the cpufreq driver. This
40 * piece of code is only for compatibility with old Device
41 * Trees.
42 */
43 np = of_find_compatible_node(NULL, NULL, "marvell,armada-xp-cpu-clock");
44 if (!np)
45 return 0;
46
47 ret = of_address_to_resource(np, 1, &res);
48 if (ret) {
49 pr_warn(FW_WARN "not enabling cpufreq, deprecated armada-xp-cpu-clock binding\n");
50 of_node_put(np);
51 return 0;
52 }
53
54 of_node_put(np);
55
56 /*
57 * For each CPU, this loop registers the operating points
58 * supported (which are the nominal CPU frequency and half of
59 * it), and registers the clock notifier that will take care
60 * of doing the PMSU part of a frequency transition.
61 */
62 for_each_possible_cpu(cpu) {
63 struct device *cpu_dev;
64 struct clk *clk;
65 int ret;
66
67 cpu_dev = get_cpu_device(cpu);
68 if (!cpu_dev) {
69 pr_err("Cannot get CPU %d\n", cpu);
70 continue;
71 }
72
73 clk = clk_get(cpu_dev, NULL);
74 if (IS_ERR(clk)) {
75 pr_err("Cannot get clock for CPU %d\n", cpu);
76 return PTR_ERR(clk);
77 }
78
79 ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk), 0);
80 if (ret) {
81 clk_put(clk);
82 return ret;
83 }
84
85 ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk) / 2, 0);
86 if (ret) {
87 clk_put(clk);
88 dev_err(cpu_dev, "Failed to register OPPs\n");
89 goto opp_register_failed;
90 }
91
92 ret = dev_pm_opp_set_sharing_cpus(cpu_dev,
93 cpumask_of(cpu_dev->id));
94 if (ret)
95 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
96 __func__, ret);
97 clk_put(clk);
98 }
99
100 platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
101 return 0;
102
103 opp_register_failed:
104 /* As registering has failed remove all the opp for all cpus */
105 dev_pm_opp_cpumask_remove_table(cpu_possible_mask);
106
107 return ret;
108 }
109 device_initcall(armada_xp_pmsu_cpufreq_init);
110
