drivers/base/topology.c

   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 static ssize_t show_cpumap(int type, cpumask_t *mask, char *buf)
  44 {
  45         ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf;
  46         int n = 0;
  47
  48         if (len > 1) {
  49                 n = type?
  50                         cpulist_scnprintf(buf, len-2, *mask):
  51                         cpumask_scnprintf(buf, len-2, *mask);
  52                 buf[n++] = '\n';
  53                 buf[n] = '\0';
  54         }
  55         return n;
  56 }
  57
  58 #define define_siblings_show_map(name)                                  \
  59 static inline ssize_t show_##name(struct sys_device *dev, char *buf)    \
  60 {                                                                       \
  61         unsigned int cpu = dev->id;                                     \
  62         return show_cpumap(0, &(topology_##name(cpu)), buf);            \
  63 }
  64
  65 #define define_siblings_show_list(name)                                 \
  66 static inline ssize_t show_##name##_list(struct sys_device *dev, char *buf) \
  67 {                                                                       \
  68         unsigned int cpu = dev->id;                                     \
  69         return show_cpumap(1, &(topology_##name(cpu)), buf);            \
  70 }
  71
  72 #define define_siblings_show_func(name)         \
  73         define_siblings_show_map(name); define_siblings_show_list(name)
  74
  75 #ifdef  topology_physical_package_id
  76 define_id_show_func(physical_package_id);
  77 define_one_ro(physical_package_id);
  78 #define ref_physical_package_id_attr    &attr_physical_package_id.attr,
  79 #else
  80 #define ref_physical_package_id_attr
  81 #endif
  82
  83 #ifdef topology_core_id
  84 define_id_show_func(core_id);
  85 define_one_ro(core_id);
  86 #define ref_core_id_attr                &attr_core_id.attr,
  87 #else
  88 #define ref_core_id_attr
  89 #endif
  90
  91 #ifdef topology_thread_siblings
  92 define_siblings_show_func(thread_siblings);
  93 define_one_ro(thread_siblings);
  94 define_one_ro(thread_siblings_list);
  95 #define ref_thread_siblings_attr        \
  96                 &attr_thread_siblings.attr, &attr_thread_siblings_list.attr,
  97 #else
  98 #define ref_thread_siblings_attr
  99 #endif
 100
 101 #ifdef topology_core_siblings
 102 define_siblings_show_func(core_siblings);
 103 define_one_ro(core_siblings);
 104 define_one_ro(core_siblings_list);
 105 #define ref_core_siblings_attr          \
 106                 &attr_core_siblings.attr, &attr_core_siblings_list.attr,
 107 #else
 108 #define ref_core_siblings_attr
 109 #endif
 110
 111 static struct attribute *default_attrs[] = {
 112         ref_physical_package_id_attr
 113         ref_core_id_attr
 114         ref_thread_siblings_attr
 115         ref_core_siblings_attr
 116         NULL
 117 };
 118
 119 static struct attribute_group topology_attr_group = {
 120         .attrs = default_attrs,
 121         .name = "topology"
 122 };
 123
 124 /* Add/Remove cpu_topology interface for CPU device */
 125 static int __cpuinit topology_add_dev(unsigned int cpu)
 126 {
 127         struct sys_device *sys_dev = get_cpu_sysdev(cpu);
 128
 129         return sysfs_create_group(&sys_dev->kobj, &topology_attr_group);
 130 }
 131
 132 static void __cpuinit topology_remove_dev(unsigned int cpu)
 133 {
 134         struct sys_device *sys_dev = get_cpu_sysdev(cpu);
 135
 136         sysfs_remove_group(&sys_dev->kobj, &topology_attr_group);
 137 }
 138
 139 static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,
 140                                            unsigned long action, void *hcpu)
 141 {
 142         unsigned int cpu = (unsigned long)hcpu;
 143         int rc = 0;
 144
 145         switch (action) {
 146         case CPU_UP_PREPARE:
 147         case CPU_UP_PREPARE_FROZEN:
 148                 rc = topology_add_dev(cpu);
 149                 break;
 150         case CPU_UP_CANCELED:
 151         case CPU_UP_CANCELED_FROZEN:
 152         case CPU_DEAD:
 153         case CPU_DEAD_FROZEN:
 154                 topology_remove_dev(cpu);
 155                 break;
 156         }
 157         return rc ? NOTIFY_BAD : NOTIFY_OK;
 158 }
 159
 160 static int __cpuinit topology_sysfs_init(void)
 161 {
 162         int cpu;
 163         int rc;
 164
 165         for_each_online_cpu(cpu) {
 166                 rc = topology_add_dev(cpu);
 167                 if (rc)
 168                         return rc;
 169         }
 170         hotcpu_notifier(topology_cpu_callback, 0);
 171
 172         return 0;
 173 }
 174
 175 device_initcall(topology_sysfs_init);