1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * CPUFreq support for Armada 370/XP platforms. 4 * 5 * Copyright (C) 2012-2016 Marvell 6 * 7 * Yehuda Yitschak <yehuday@marvell.com> 8 * Gregory Clement <gregory.clement@free-electrons.com> 9 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> 10 */ 11 12 #define pr_fmt(fmt) "mvebu-pmsu: " fmt 13 14 #include <linux/clk.h> 15 #include <linux/cpu.h> 16 #include <linux/init.h> 17 #include <linux/kernel.h> 18 #include <linux/of_address.h> 19 #include <linux/platform_device.h> 20 #include <linux/pm_opp.h> 21 #include <linux/resource.h> 22 23 static int __init armada_xp_pmsu_cpufreq_init(void) 24 { 25 struct device_node *np; 26 struct resource res; 27 int ret, cpu; 28 29 if (!of_machine_is_compatible("marvell,armadaxp")) 30 return 0; 31 32 /* 33 * In order to have proper cpufreq handling, we need to ensure 34 * that the Device Tree description of the CPU clock includes 35 * the definition of the PMU DFS registers. If not, we do not 36 * register the clock notifier and the cpufreq driver. This 37 * piece of code is only for compatibility with old Device 38 * Trees. 39 */ 40 np = of_find_compatible_node(NULL, NULL, "marvell,armada-xp-cpu-clock"); 41 if (!np) 42 return 0; 43 44 ret = of_address_to_resource(np, 1, &res); 45 if (ret) { 46 pr_warn(FW_WARN "not enabling cpufreq, deprecated armada-xp-cpu-clock binding\n"); 47 of_node_put(np); 48 return 0; 49 } 50 51 of_node_put(np); 52 53 /* 54 * For each CPU, this loop registers the operating points 55 * supported (which are the nominal CPU frequency and half of 56 * it), and registers the clock notifier that will take care 57 * of doing the PMSU part of a frequency transition. 58 */ 59 for_each_possible_cpu(cpu) { 60 struct device *cpu_dev; 61 struct clk *clk; 62 int ret; 63 64 cpu_dev = get_cpu_device(cpu); 65 if (!cpu_dev) { 66 pr_err("Cannot get CPU %d\n", cpu); 67 continue; 68 } 69 70 clk = clk_get(cpu_dev, NULL); 71 if (IS_ERR(clk)) { 72 pr_err("Cannot get clock for CPU %d\n", cpu); 73 return PTR_ERR(clk); 74 } 75 76 ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk), 0); 77 if (ret) { 78 clk_put(clk); 79 return ret; 80 } 81 82 ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk) / 2, 0); 83 if (ret) { 84 dev_pm_opp_remove(cpu_dev, clk_get_rate(clk)); 85 clk_put(clk); 86 dev_err(cpu_dev, "Failed to register OPPs\n"); 87 return ret; 88 } 89 90 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, 91 cpumask_of(cpu_dev->id)); 92 if (ret) 93 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", 94 __func__, ret); 95 clk_put(clk); 96 } 97 98 platform_device_register_simple("cpufreq-dt", -1, NULL, 0); 99 return 0; 100 } 101 device_initcall(armada_xp_pmsu_cpufreq_init); 102