1 /* 2 * driver/base/topology.c - Populate sysfs with cpu topology information 3 * 4 * Written by: Zhang Yanmin, Intel Corporation 5 * 6 * Copyright (C) 2006, Intel Corp. 7 * 8 * All rights reserved. 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; either version 2 of the License, or 13 * (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, but 16 * WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 18 * NON INFRINGEMENT. See the GNU General Public License for more 19 * details. 20 * 21 * You should have received a copy of the GNU General Public License 22 * along with this program; if not, write to the Free Software 23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 24 * 25 */ 26 #include <linux/sysdev.h> 27 #include <linux/init.h> 28 #include <linux/mm.h> 29 #include <linux/cpu.h> 30 #include <linux/module.h> 31 #include <linux/topology.h> 32 33 #define define_one_ro(_name) \ 34 static SYSDEV_ATTR(_name, 0444, show_##_name, NULL) 35 36 #define define_id_show_func(name) \ 37 static ssize_t show_##name(struct sys_device *dev, char *buf) \ 38 { \ 39 unsigned int cpu = dev->id; \ 40 return sprintf(buf, "%d\n", topology_##name(cpu)); \ 41 } 42 43 #define define_siblings_show_func(name) \ 44 static ssize_t show_##name(struct sys_device *dev, char *buf) \ 45 { \ 46 ssize_t len = -1; \ 47 unsigned int cpu = dev->id; \ 48 len = cpumask_scnprintf(buf, NR_CPUS+1, topology_##name(cpu)); \ 49 return (len + sprintf(buf + len, "\n")); \ 50 } 51 52 #ifdef topology_physical_package_id 53 define_id_show_func(physical_package_id); 54 define_one_ro(physical_package_id); 55 #define ref_physical_package_id_attr &attr_physical_package_id.attr, 56 #else 57 #define ref_physical_package_id_attr 58 #endif 59 60 #ifdef topology_core_id 61 define_id_show_func(core_id); 62 define_one_ro(core_id); 63 #define ref_core_id_attr &attr_core_id.attr, 64 #else 65 #define ref_core_id_attr 66 #endif 67 68 #ifdef topology_thread_siblings 69 define_siblings_show_func(thread_siblings); 70 define_one_ro(thread_siblings); 71 #define ref_thread_siblings_attr &attr_thread_siblings.attr, 72 #else 73 #define ref_thread_siblings_attr 74 #endif 75 76 #ifdef topology_core_siblings 77 define_siblings_show_func(core_siblings); 78 define_one_ro(core_siblings); 79 #define ref_core_siblings_attr &attr_core_siblings.attr, 80 #else 81 #define ref_core_siblings_attr 82 #endif 83 84 static struct attribute *default_attrs[] = { 85 ref_physical_package_id_attr 86 ref_core_id_attr 87 ref_thread_siblings_attr 88 ref_core_siblings_attr 89 NULL 90 }; 91 92 static struct attribute_group topology_attr_group = { 93 .attrs = default_attrs, 94 .name = "topology" 95 }; 96 97 /* Add/Remove cpu_topology interface for CPU device */ 98 static int __cpuinit topology_add_dev(unsigned int cpu) 99 { 100 struct sys_device *sys_dev = get_cpu_sysdev(cpu); 101 102 return sysfs_create_group(&sys_dev->kobj, &topology_attr_group); 103 } 104 105 static void __cpuinit topology_remove_dev(unsigned int cpu) 106 { 107 struct sys_device *sys_dev = get_cpu_sysdev(cpu); 108 109 sysfs_remove_group(&sys_dev->kobj, &topology_attr_group); 110 } 111 112 static int __cpuinit topology_cpu_callback(struct notifier_block *nfb, 113 unsigned long action, void *hcpu) 114 { 115 unsigned int cpu = (unsigned long)hcpu; 116 int rc = 0; 117 118 switch (action) { 119 case CPU_UP_PREPARE: 120 case CPU_UP_PREPARE_FROZEN: 121 rc = topology_add_dev(cpu); 122 break; 123 case CPU_UP_CANCELED: 124 case CPU_UP_CANCELED_FROZEN: 125 case CPU_DEAD: 126 case CPU_DEAD_FROZEN: 127 topology_remove_dev(cpu); 128 break; 129 } 130 return rc ? NOTIFY_BAD : NOTIFY_OK; 131 } 132 133 static int __cpuinit topology_sysfs_init(void) 134 { 135 int cpu; 136 int rc; 137 138 for_each_online_cpu(cpu) { 139 rc = topology_add_dev(cpu); 140 if (rc) 141 return rc; 142 } 143 hotcpu_notifier(topology_cpu_callback, 0); 144 145 return 0; 146 } 147 148 device_initcall(topology_sysfs_init); 149