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 #include <linux/kernel.h> 18 #include <linux/types.h> 19 #include <acpi/acpi_bus.h> 20 #include <acpi/acpi_drivers.h> 21 #include <asm/xen/hypercall.h> 22 #include <xen/interface/version.h> 23 #include <xen/xen-ops.h> 24 25 #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad" 26 #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator" 27 #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80 28 static DEFINE_MUTEX(xen_cpu_lock); 29 30 static int xen_acpi_pad_idle_cpus(unsigned int idle_nums) 31 { 32 struct xen_platform_op op; 33 34 op.cmd = XENPF_core_parking; 35 op.u.core_parking.type = XEN_CORE_PARKING_SET; 36 op.u.core_parking.idle_nums = idle_nums; 37 38 return HYPERVISOR_dom0_op(&op); 39 } 40 41 static int xen_acpi_pad_idle_cpus_num(void) 42 { 43 struct xen_platform_op op; 44 45 op.cmd = XENPF_core_parking; 46 op.u.core_parking.type = XEN_CORE_PARKING_GET; 47 48 return HYPERVISOR_dom0_op(&op) 49 ?: op.u.core_parking.idle_nums; 50 } 51 52 /* 53 * Query firmware how many CPUs should be idle 54 * return -1 on failure 55 */ 56 static int acpi_pad_pur(acpi_handle handle) 57 { 58 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; 59 union acpi_object *package; 60 int num = -1; 61 62 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer))) 63 return num; 64 65 if (!buffer.length || !buffer.pointer) 66 return num; 67 68 package = buffer.pointer; 69 70 if (package->type == ACPI_TYPE_PACKAGE && 71 package->package.count == 2 && 72 package->package.elements[0].integer.value == 1) /* rev 1 */ 73 num = package->package.elements[1].integer.value; 74 75 kfree(buffer.pointer); 76 return num; 77 } 78 79 /* Notify firmware how many CPUs are idle */ 80 static void acpi_pad_ost(acpi_handle handle, int stat, 81 uint32_t idle_nums) 82 { 83 union acpi_object params[3] = { 84 {.type = ACPI_TYPE_INTEGER,}, 85 {.type = ACPI_TYPE_INTEGER,}, 86 {.type = ACPI_TYPE_BUFFER,}, 87 }; 88 struct acpi_object_list arg_list = {3, params}; 89 90 params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY; 91 params[1].integer.value = stat; 92 params[2].buffer.length = 4; 93 params[2].buffer.pointer = (void *)&idle_nums; 94 acpi_evaluate_object(handle, "_OST", &arg_list, NULL); 95 } 96 97 static void acpi_pad_handle_notify(acpi_handle handle) 98 { 99 int idle_nums; 100 101 mutex_lock(&xen_cpu_lock); 102 idle_nums = acpi_pad_pur(handle); 103 if (idle_nums < 0) { 104 mutex_unlock(&xen_cpu_lock); 105 return; 106 } 107 108 idle_nums = xen_acpi_pad_idle_cpus(idle_nums) 109 ?: xen_acpi_pad_idle_cpus_num(); 110 if (idle_nums >= 0) 111 acpi_pad_ost(handle, 0, idle_nums); 112 mutex_unlock(&xen_cpu_lock); 113 } 114 115 static void acpi_pad_notify(acpi_handle handle, u32 event, 116 void *data) 117 { 118 switch (event) { 119 case ACPI_PROCESSOR_AGGREGATOR_NOTIFY: 120 acpi_pad_handle_notify(handle); 121 break; 122 default: 123 pr_warn("Unsupported event [0x%x]\n", event); 124 break; 125 } 126 } 127 128 static int acpi_pad_add(struct acpi_device *device) 129 { 130 acpi_status status; 131 132 strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME); 133 strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS); 134 135 status = acpi_install_notify_handler(device->handle, 136 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device); 137 if (ACPI_FAILURE(status)) 138 return -ENODEV; 139 140 return 0; 141 } 142 143 static int acpi_pad_remove(struct acpi_device *device, 144 int type) 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