| Viresh Kumar | 9f123de | 2016-04-27 08:52:27 +0530 | [diff] [blame] | 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 | |
| 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, 0); |
| 74 | if (IS_ERR(clk)) { |
| 75 | pr_err("Cannot get clock for CPU %d\n", cpu); |
| 76 | return PTR_ERR(clk); |
| 77 | } |
| 78 | |
| 79 | /* |
| 80 | * In case of a failure of dev_pm_opp_add(), we don't |
| 81 | * bother with cleaning up the registered OPP (there's |
| 82 | * no function to do so), and simply cancel the |
| 83 | * registration of the cpufreq device. |
| 84 | */ |
| 85 | ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk), 0); |
| 86 | if (ret) { |
| 87 | clk_put(clk); |
| 88 | return ret; |
| 89 | } |
| 90 | |
| 91 | ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk) / 2, 0); |
| 92 | if (ret) { |
| 93 | clk_put(clk); |
| 94 | return ret; |
| 95 | } |
| 96 | |
| 97 | ret = dev_pm_opp_set_sharing_cpus(cpu_dev, |
| 98 | cpumask_of(cpu_dev->id)); |
| 99 | if (ret) |
| 100 | dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", |
| 101 | __func__, ret); |
| 102 | } |
| 103 | |
| 104 | platform_device_register_simple("cpufreq-dt", -1, NULL, 0); |
| 105 | return 0; |
| 106 | } |
| 107 | device_initcall(armada_xp_pmsu_cpufreq_init); |