1 /* 2 * System Control and Power Interface (SCPI) based CPUFreq Interface driver 3 * 4 * It provides necessary ops to arm_big_little cpufreq driver. 5 * 6 * Copyright (C) 2015 ARM Ltd. 7 * Sudeep Holla <sudeep.holla@arm.com> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 * 13 * This program is distributed "as is" WITHOUT ANY WARRANTY of any 14 * kind, whether express or implied; without even the implied warranty 15 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 */ 18 19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 20 21 #include <linux/cpufreq.h> 22 #include <linux/module.h> 23 #include <linux/platform_device.h> 24 #include <linux/pm_opp.h> 25 #include <linux/scpi_protocol.h> 26 #include <linux/types.h> 27 28 #include "arm_big_little.h" 29 30 static struct scpi_ops *scpi_ops; 31 32 static struct scpi_dvfs_info *scpi_get_dvfs_info(struct device *cpu_dev) 33 { 34 int domain = topology_physical_package_id(cpu_dev->id); 35 36 if (domain < 0) 37 return ERR_PTR(-EINVAL); 38 return scpi_ops->dvfs_get_info(domain); 39 } 40 41 static int scpi_opp_table_ops(struct device *cpu_dev, bool remove) 42 { 43 int idx, ret = 0; 44 struct scpi_opp *opp; 45 struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev); 46 47 if (IS_ERR(info)) 48 return PTR_ERR(info); 49 50 if (!info->opps) 51 return -EIO; 52 53 for (opp = info->opps, idx = 0; idx < info->count; idx++, opp++) { 54 if (remove) 55 dev_pm_opp_remove(cpu_dev, opp->freq); 56 else 57 ret = dev_pm_opp_add(cpu_dev, opp->freq, 58 opp->m_volt * 1000); 59 if (ret) { 60 dev_warn(cpu_dev, "failed to add opp %uHz %umV\n", 61 opp->freq, opp->m_volt); 62 while (idx-- > 0) 63 dev_pm_opp_remove(cpu_dev, (--opp)->freq); 64 return ret; 65 } 66 } 67 return ret; 68 } 69 70 static int scpi_get_transition_latency(struct device *cpu_dev) 71 { 72 struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev); 73 74 if (IS_ERR(info)) 75 return PTR_ERR(info); 76 return info->latency; 77 } 78 79 static int scpi_init_opp_table(struct device *cpu_dev) 80 { 81 return scpi_opp_table_ops(cpu_dev, false); 82 } 83 84 static void scpi_free_opp_table(struct device *cpu_dev) 85 { 86 scpi_opp_table_ops(cpu_dev, true); 87 } 88 89 static struct cpufreq_arm_bL_ops scpi_cpufreq_ops = { 90 .name = "scpi", 91 .get_transition_latency = scpi_get_transition_latency, 92 .init_opp_table = scpi_init_opp_table, 93 .free_opp_table = scpi_free_opp_table, 94 }; 95 96 static int scpi_cpufreq_probe(struct platform_device *pdev) 97 { 98 scpi_ops = get_scpi_ops(); 99 if (!scpi_ops) 100 return -EIO; 101 102 return bL_cpufreq_register(&scpi_cpufreq_ops); 103 } 104 105 static int scpi_cpufreq_remove(struct platform_device *pdev) 106 { 107 bL_cpufreq_unregister(&scpi_cpufreq_ops); 108 scpi_ops = NULL; 109 return 0; 110 } 111 112 static struct platform_driver scpi_cpufreq_platdrv = { 113 .driver = { 114 .name = "scpi-cpufreq", 115 .owner = THIS_MODULE, 116 }, 117 .probe = scpi_cpufreq_probe, 118 .remove = scpi_cpufreq_remove, 119 }; 120 module_platform_driver(scpi_cpufreq_platdrv); 121 122 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); 123 MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver"); 124 MODULE_LICENSE("GPL v2"); 125