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 #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 static cpumask_t topology_dev_map = CPU_MASK_NONE;
  98
  99 /* Add/Remove cpu_topology interface for CPU device */
 100 static int __cpuinit topology_add_dev(unsigned int cpu)
 101 {
 102         int rc;
 103         struct sys_device *sys_dev = get_cpu_sysdev(cpu);
 104
 105         rc = sysfs_create_group(&sys_dev->kobj, &topology_attr_group);
 106         if (!rc)
 107                 cpu_set(cpu, topology_dev_map);
 108         return rc;
 109 }
 110
 111 static void __cpuinit topology_remove_dev(unsigned int cpu)
 112 {
 113         struct sys_device *sys_dev = get_cpu_sysdev(cpu);
 114
 115         if (!cpu_isset(cpu, topology_dev_map))
 116                 return;
 117         cpu_clear(cpu, topology_dev_map);
 118         sysfs_remove_group(&sys_dev->kobj, &topology_attr_group);
 119 }
 120
 121 static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,
 122                                            unsigned long action, void *hcpu)
 123 {
 124         unsigned int cpu = (unsigned long)hcpu;
 125         int rc = 0;
 126
 127         switch (action) {
 128         case CPU_UP_PREPARE:
 129                 rc = topology_add_dev(cpu);
 130                 break;
 131         case CPU_UP_CANCELED:
 132         case CPU_DEAD:
 133                 topology_remove_dev(cpu);
 134                 break;
 135         }
 136         return rc ? NOTIFY_BAD : NOTIFY_OK;
 137 }
 138
 139 static int __cpuinit topology_sysfs_init(void)
 140 {
 141         int cpu;
 142         int rc;
 143
 144         for_each_online_cpu(cpu) {
 145                 rc = topology_add_dev(cpu);
 146                 if (rc)
 147                         return rc;
 148         }
 149         hotcpu_notifier(topology_cpu_callback, 0);
 150
 151         return 0;
 152 }
 153
 154 device_initcall(topology_sysfs_init);