1 /* 2 * xen-acpi-pad.c - Xen pad interface 3 * 4 * Copyright (c) 2012, Intel Corporation. 5 * Author: Liu, Jinsong <jinsong.liu@intel.com> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms and conditions of the GNU General Public License, 9 * version 2, as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 14 * more details. 15 */ 16 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 19 #include <linux/kernel.h> 20 #include <linux/types.h> 21 #include <linux/acpi.h> 22 #include <xen/interface/version.h> 23 #include <xen/xen-ops.h> 24 #include <asm/xen/hypercall.h> 25 26 #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad" 27 #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator" 28 #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80 29 static DEFINE_MUTEX(xen_cpu_lock); 30 31 static int xen_acpi_pad_idle_cpus(unsigned int idle_nums) 32 { 33 struct xen_platform_op op; 34 35 op.cmd = XENPF_core_parking; 36 op.u.core_parking.type = XEN_CORE_PARKING_SET; 37 op.u.core_parking.idle_nums = idle_nums; 38 39 return HYPERVISOR_dom0_op(&op); 40 } 41 42 static int xen_acpi_pad_idle_cpus_num(void) 43 { 44 struct xen_platform_op op; 45 46 op.cmd = XENPF_core_parking; 47 op.u.core_parking.type = XEN_CORE_PARKING_GET; 48 49 return HYPERVISOR_dom0_op(&op) 50 ?: op.u.core_parking.idle_nums; 51 } 52 53 /* 54 * Query firmware how many CPUs should be idle 55 * return -1 on failure 56 */ 57 static int acpi_pad_pur(acpi_handle handle) 58 { 59 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; 60 union acpi_object *package; 61 int num = -1; 62 63 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer))) 64 return num; 65 66 if (!buffer.length || !buffer.pointer) 67 return num; 68 69 package = buffer.pointer; 70 71 if (package->type == ACPI_TYPE_PACKAGE && 72 package->package.count == 2 && 73 package->package.elements[0].integer.value == 1) /* rev 1 */ 74 num = package->package.elements[1].integer.value; 75 76 kfree(buffer.pointer); 77 return num; 78 } 79 80 /* Notify firmware how many CPUs are idle */ 81 static void acpi_pad_ost(acpi_handle handle, int stat, 82 uint32_t idle_nums) 83 { 84 union acpi_object params[3] = { 85 {.type = ACPI_TYPE_INTEGER,}, 86 {.type = ACPI_TYPE_INTEGER,}, 87 {.type = ACPI_TYPE_BUFFER,}, 88 }; 89 struct acpi_object_list arg_list = {3, params}; 90 91 params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY; 92 params[1].integer.value = stat; 93 params[2].buffer.length = 4; 94 params[2].buffer.pointer = (void *)&idle_nums; 95 acpi_evaluate_object(handle, "_OST", &arg_list, NULL); 96 } 97 98 static void acpi_pad_handle_notify(acpi_handle handle) 99 { 100 int idle_nums; 101 102 mutex_lock(&xen_cpu_lock); 103 idle_nums = acpi_pad_pur(handle); 104 if (idle_nums < 0) { 105 mutex_unlock(&xen_cpu_lock); 106 return; 107 } 108 109 idle_nums = xen_acpi_pad_idle_cpus(idle_nums) 110 ?: xen_acpi_pad_idle_cpus_num(); 111 if (idle_nums >= 0) 112 acpi_pad_ost(handle, 0, idle_nums); 113 mutex_unlock(&xen_cpu_lock); 114 } 115 116 static void acpi_pad_notify(acpi_handle handle, u32 event, 117 void *data) 118 { 119 switch (event) { 120 case ACPI_PROCESSOR_AGGREGATOR_NOTIFY: 121 acpi_pad_handle_notify(handle); 122 break; 123 default: 124 pr_warn("Unsupported event [0x%x]\n", event); 125 break; 126 } 127 } 128 129 static int acpi_pad_add(struct acpi_device *device) 130 { 131 acpi_status status; 132 133 strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME); 134 strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS); 135 136 status = acpi_install_notify_handler(device->handle, 137 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device); 138 if (ACPI_FAILURE(status)) 139 return -ENODEV; 140 141 return 0; 142 } 143 144 static int acpi_pad_remove(struct acpi_device *device) 145 { 146 mutex_lock(&xen_cpu_lock); 147 xen_acpi_pad_idle_cpus(0); 148 mutex_unlock(&xen_cpu_lock); 149 150 acpi_remove_notify_handler(device->handle, 151 ACPI_DEVICE_NOTIFY, acpi_pad_notify); 152 return 0; 153 } 154 155 static const struct acpi_device_id pad_device_ids[] = { 156 {"ACPI000C", 0}, 157 {"", 0}, 158 }; 159 160 static struct acpi_driver acpi_pad_driver = { 161 .name = "processor_aggregator", 162 .class = ACPI_PROCESSOR_AGGREGATOR_CLASS, 163 .ids = pad_device_ids, 164 .ops = { 165 .add = acpi_pad_add, 166 .remove = acpi_pad_remove, 167 }, 168 }; 169 170 static int __init xen_acpi_pad_init(void) 171 { 172 /* Only DOM0 is responsible for Xen acpi pad */ 173 if (!xen_initial_domain()) 174 return -ENODEV; 175 176 /* Only Xen4.2 or later support Xen acpi pad */ 177 if (!xen_running_on_version_or_later(4, 2)) 178 return -ENODEV; 179 180 return acpi_bus_register_driver(&acpi_pad_driver); 181 } 182 subsys_initcall(xen_acpi_pad_init); 183