arch/sparc/kernel/hvapi.c

   1 /* hvapi.c: Hypervisor API management.
   2  *
   3  * Copyright (C) 2007 David S. Miller <davem@davemloft.net>
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/module.h>
   7 #include <linux/init.h>
   8
   9 #include <asm/hypervisor.h>
  10 #include <asm/oplib.h>
  11
  12 /* If the hypervisor indicates that the API setting
  13  * calls are unsupported, by returning HV_EBADTRAP or
  14  * HV_ENOTSUPPORTED, we assume that API groups with the
  15  * PRE_API flag set are major 1 minor 0.
  16  */
  17 struct api_info {
  18         unsigned long group;
  19         unsigned long major;
  20         unsigned long minor;
  21         unsigned int refcnt;
  22         unsigned int flags;
  23 #define FLAG_PRE_API            0x00000001
  24 };
  25
  26 static struct api_info api_table[] = {
  27         { .group = HV_GRP_SUN4V,        .flags = FLAG_PRE_API   },
  28         { .group = HV_GRP_CORE,         .flags = FLAG_PRE_API   },
  29         { .group = HV_GRP_INTR,                                 },
  30         { .group = HV_GRP_SOFT_STATE,                           },
  31         { .group = HV_GRP_PCI,          .flags = FLAG_PRE_API   },
  32         { .group = HV_GRP_LDOM,                                 },
  33         { .group = HV_GRP_SVC_CHAN,     .flags = FLAG_PRE_API   },
  34         { .group = HV_GRP_NCS,          .flags = FLAG_PRE_API   },
  35         { .group = HV_GRP_RNG,                                  },
  36         { .group = HV_GRP_NIAG_PERF,    .flags = FLAG_PRE_API   },
  37         { .group = HV_GRP_FIRE_PERF,                            },
  38         { .group = HV_GRP_N2_CPU,                               },
  39         { .group = HV_GRP_NIU,                                  },
  40         { .group = HV_GRP_VF_CPU,                               },
  41         { .group = HV_GRP_DIAG,         .flags = FLAG_PRE_API   },
  42 };
  43
  44 static DEFINE_SPINLOCK(hvapi_lock);
  45
  46 static struct api_info *__get_info(unsigned long group)
  47 {
  48         int i;
  49
  50         for (i = 0; i < ARRAY_SIZE(api_table); i++) {
  51                 if (api_table[i].group == group)
  52                         return &api_table[i];
  53         }
  54         return NULL;
  55 }
  56
  57 static void __get_ref(struct api_info *p)
  58 {
  59         p->refcnt++;
  60 }
  61
  62 static void __put_ref(struct api_info *p)
  63 {
  64         if (--p->refcnt == 0) {
  65                 unsigned long ignore;
  66
  67                 sun4v_set_version(p->group, 0, 0, &ignore);
  68                 p->major = p->minor = 0;
  69         }
  70 }
  71
  72 /* Register a hypervisor API specification.  It indicates the
  73  * API group and desired major+minor.
  74  *
  75  * If an existing API registration exists '0' (success) will
  76  * be returned if it is compatible with the one being registered.
  77  * Otherwise a negative error code will be returned.
  78  *
  79  * Otherwise an attempt will be made to negotiate the requested
  80  * API group/major/minor with the hypervisor, and errors returned
  81  * if that does not succeed.
  82  */
  83 int sun4v_hvapi_register(unsigned long group, unsigned long major,
  84                          unsigned long *minor)
  85 {
  86         struct api_info *p;
  87         unsigned long flags;
  88         int ret;
  89
  90         spin_lock_irqsave(&hvapi_lock, flags);
  91         p = __get_info(group);
  92         ret = -EINVAL;
  93         if (p) {
  94                 if (p->refcnt) {
  95                         ret = -EINVAL;
  96                         if (p->major == major) {
  97                                 *minor = p->minor;
  98                                 ret = 0;
  99                         }
 100                 } else {
 101                         unsigned long actual_minor;
 102                         unsigned long hv_ret;
 103
 104                         hv_ret = sun4v_set_version(group, major, *minor,
 105                                                    &actual_minor);
 106                         ret = -EINVAL;
 107                         if (hv_ret == HV_EOK) {
 108                                 *minor = actual_minor;
 109                                 p->major = major;
 110                                 p->minor = actual_minor;
 111                                 ret = 0;
 112                         } else if (hv_ret == HV_EBADTRAP ||
 113                                    hv_ret == HV_ENOTSUPPORTED) {
 114                                 if (p->flags & FLAG_PRE_API) {
 115                                         if (major == 1) {
 116                                                 p->major = 1;
 117                                                 p->minor = 0;
 118                                                 *minor = 0;
 119                                                 ret = 0;
 120                                         }
 121                                 }
 122                         }
 123                 }
 124
 125                 if (ret == 0)
 126                         __get_ref(p);
 127         }
 128         spin_unlock_irqrestore(&hvapi_lock, flags);
 129
 130         return ret;
 131 }
 132 EXPORT_SYMBOL(sun4v_hvapi_register);
 133
 134 void sun4v_hvapi_unregister(unsigned long group)
 135 {
 136         struct api_info *p;
 137         unsigned long flags;
 138
 139         spin_lock_irqsave(&hvapi_lock, flags);
 140         p = __get_info(group);
 141         if (p)
 142                 __put_ref(p);
 143         spin_unlock_irqrestore(&hvapi_lock, flags);
 144 }
 145 EXPORT_SYMBOL(sun4v_hvapi_unregister);
 146
 147 int sun4v_hvapi_get(unsigned long group,
 148                     unsigned long *major,
 149                     unsigned long *minor)
 150 {
 151         struct api_info *p;
 152         unsigned long flags;
 153         int ret;
 154
 155         spin_lock_irqsave(&hvapi_lock, flags);
 156         ret = -EINVAL;
 157         p = __get_info(group);
 158         if (p && p->refcnt) {
 159                 *major = p->major;
 160                 *minor = p->minor;
 161                 ret = 0;
 162         }
 163         spin_unlock_irqrestore(&hvapi_lock, flags);
 164
 165         return ret;
 166 }
 167 EXPORT_SYMBOL(sun4v_hvapi_get);
 168
 169 void __init sun4v_hvapi_init(void)
 170 {
 171         unsigned long group, major, minor;
 172
 173         group = HV_GRP_SUN4V;
 174         major = 1;
 175         minor = 0;
 176         if (sun4v_hvapi_register(group, major, &minor))
 177                 goto bad;
 178
 179         group = HV_GRP_CORE;
 180         major = 1;
 181         minor = 1;
 182         if (sun4v_hvapi_register(group, major, &minor))
 183                 goto bad;
 184
 185         return;
 186
 187 bad:
 188         prom_printf("HVAPI: Cannot register API group "
 189                     "%lx with major(%u) minor(%u)\n",
 190                     group, major, minor);
 191         prom_halt();
 192 }