drivers/s390/char/sclp_config.c

   1 /*
   2  *  drivers/s390/char/sclp_config.c
   3  *
   4  *    Copyright IBM Corp. 2007
   5  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/errno.h>
  10 #include <linux/cpu.h>
  11 #include <linux/kthread.h>
  12 #include <linux/sysdev.h>
  13 #include <linux/workqueue.h>
  14 #include <asm/smp.h>
  15 #include "sclp.h"
  16
  17 #define TAG     "sclp_config: "
  18
  19 struct conf_mgm_data {
  20         u8 reserved;
  21         u8 ev_qualifier;
  22 } __attribute__((packed));
  23
  24 #define EV_QUAL_CPU_CHANGE      1
  25 #define EV_QUAL_CAP_CHANGE      3
  26
  27 static struct work_struct sclp_cpu_capability_work;
  28 static struct work_struct sclp_cpu_change_work;
  29
  30 static void sclp_cpu_capability_notify(struct work_struct *work)
  31 {
  32         int cpu;
  33         struct sys_device *sysdev;
  34
  35         printk(KERN_WARNING TAG "cpu capability changed.\n");
  36         get_online_cpus();
  37         for_each_online_cpu(cpu) {
  38                 sysdev = get_cpu_sysdev(cpu);
  39                 kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
  40         }
  41         put_online_cpus();
  42 }
  43
  44 static int sclp_cpu_kthread(void *data)
  45 {
  46         smp_rescan_cpus();
  47         return 0;
  48 }
  49
  50 static void __ref sclp_cpu_change_notify(struct work_struct *work)
  51 {
  52         /* Can't call smp_rescan_cpus() from  workqueue context since it may
  53          * deadlock in case of cpu hotplug. So we have to create a kernel
  54          * thread in order to call it.
  55          */
  56         kthread_run(sclp_cpu_kthread, NULL, "cpu_rescan");
  57 }
  58
  59 static void sclp_conf_receiver_fn(struct evbuf_header *evbuf)
  60 {
  61         struct conf_mgm_data *cdata;
  62
  63         cdata = (struct conf_mgm_data *)(evbuf + 1);
  64         switch (cdata->ev_qualifier) {
  65         case EV_QUAL_CPU_CHANGE:
  66                 schedule_work(&sclp_cpu_change_work);
  67                 break;
  68         case EV_QUAL_CAP_CHANGE:
  69                 schedule_work(&sclp_cpu_capability_work);
  70                 break;
  71         }
  72 }
  73
  74 static struct sclp_register sclp_conf_register =
  75 {
  76         .receive_mask = EVTYP_CONFMGMDATA_MASK,
  77         .receiver_fn  = sclp_conf_receiver_fn,
  78 };
  79
  80 static int __init sclp_conf_init(void)
  81 {
  82         int rc;
  83
  84         INIT_WORK(&sclp_cpu_capability_work, sclp_cpu_capability_notify);
  85         INIT_WORK(&sclp_cpu_change_work, sclp_cpu_change_notify);
  86
  87         rc = sclp_register(&sclp_conf_register);
  88         if (rc)
  89                 return rc;
  90
  91         if (!(sclp_conf_register.sclp_send_mask & EVTYP_CONFMGMDATA_MASK)) {
  92                 printk(KERN_WARNING TAG "no configuration management.\n");
  93                 sclp_unregister(&sclp_conf_register);
  94                 rc = -ENOSYS;
  95         }
  96         return rc;
  97 }
  98
  99 __initcall(sclp_conf_init);