arch/sparc64/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 #include <linux/slab.h>
   9
  10 #include <asm/hypervisor.h>
  11 #include <asm/oplib.h>
  12
  13 /* If the hypervisor indicates that the API setting
  14  * calls are unsupported, by returning HV_EBADTRAP or
  15  * HV_ENOTSUPPORTED, we assume that API groups with the
  16  * PRE_API flag set are major 1 minor 0.
  17  */
  18 struct api_info {
  19         unsigned long group;
  20         unsigned long major;
  21         unsigned long minor;
  22         unsigned int refcnt;
  23         unsigned int flags;
  24 #define FLAG_PRE_API            0x00000001
  25 };
  26
  27 static struct api_info api_table[] = {
  28         { .group = HV_GRP_SUN4V,        .flags = FLAG_PRE_API   },
  29         { .group = HV_GRP_CORE,         .flags = FLAG_PRE_API   },
  30         { .group = HV_GRP_INTR,                                 },
  31         { .group = HV_GRP_SOFT_STATE,                           },
  32         { .group = HV_GRP_PCI,          .flags = FLAG_PRE_API   },
  33         { .group = HV_GRP_LDOM,                                 },
  34         { .group = HV_GRP_SVC_CHAN,     .flags = FLAG_PRE_API   },
  35         { .group = HV_GRP_NCS,          .flags = FLAG_PRE_API   },
  36         { .group = HV_GRP_NIAG_PERF,    .flags = FLAG_PRE_API   },
  37         { .group = HV_GRP_FIRE_PERF,                            },
  38         { .group = HV_GRP_DIAG,         .flags = FLAG_PRE_API   },
  39 };
  40
  41 static DEFINE_SPINLOCK(hvapi_lock);
  42
  43 static struct api_info *__get_info(unsigned long group)
  44 {
  45         int i;
  46
  47         for (i = 0; i < ARRAY_SIZE(api_table); i++) {
  48                 if (api_table[i].group == group)
  49                         return &api_table[i];
  50         }
  51         return NULL;
  52 }
  53
  54 static void __get_ref(struct api_info *p)
  55 {
  56         p->refcnt++;
  57 }
  58
  59 static void __put_ref(struct api_info *p)
  60 {
  61         if (--p->refcnt == 0) {
  62                 unsigned long ignore;
  63
  64                 sun4v_set_version(p->group, 0, 0, &ignore);
  65                 p->major = p->minor = 0;
  66         }
  67 }
  68
  69 /* Register a hypervisor API specification.  It indicates the
  70  * API group and desired major+minor.
  71  *
  72  * If an existing API registration exists '0' (success) will
  73  * be returned if it is compatible with the one being registered.
  74  * Otherwise a negative error code will be returned.
  75  *
  76  * Otherwise an attempt will be made to negotiate the requested
  77  * API group/major/minor with the hypervisor, and errors returned
  78  * if that does not succeed.
  79  */
  80 int sun4v_hvapi_register(unsigned long group, unsigned long major,
  81                          unsigned long *minor)
  82 {
  83         struct api_info *p;
  84         unsigned long flags;
  85         int ret;
  86
  87         spin_lock_irqsave(&hvapi_lock, flags);
  88         p = __get_info(group);
  89         ret = -EINVAL;
  90         if (p) {
  91                 if (p->refcnt) {
  92                         ret = -EINVAL;
  93                         if (p->major == major) {
  94                                 *minor = p->minor;
  95                                 ret = 0;
  96                         }
  97                 } else {
  98                         unsigned long actual_minor;
  99                         unsigned long hv_ret;
 100
 101                         hv_ret = sun4v_set_version(group, major, *minor,
 102                                                    &actual_minor);
 103                         ret = -EINVAL;
 104                         if (hv_ret == HV_EOK) {
 105                                 *minor = actual_minor;
 106                                 p->major = major;
 107                                 p->minor = actual_minor;
 108                                 ret = 0;
 109                         } else if (hv_ret == HV_EBADTRAP ||
 110                                    HV_ENOTSUPPORTED) {
 111                                 if (p->flags & FLAG_PRE_API) {
 112                                         if (major == 1) {
 113                                                 p->major = 1;
 114                                                 p->minor = 0;
 115                                                 *minor = 0;
 116                                                 ret = 0;
 117                                         }
 118                                 }
 119                         }
 120                 }
 121
 122                 if (ret == 0)
 123                         __get_ref(p);
 124         }
 125         spin_unlock_irqrestore(&hvapi_lock, flags);
 126
 127         return ret;
 128 }
 129 EXPORT_SYMBOL(sun4v_hvapi_register);
 130
 131 void sun4v_hvapi_unregister(unsigned long group)
 132 {
 133         struct api_info *p;
 134         unsigned long flags;
 135
 136         spin_lock_irqsave(&hvapi_lock, flags);
 137         p = __get_info(group);
 138         if (p)
 139                 __put_ref(p);
 140         spin_unlock_irqrestore(&hvapi_lock, flags);
 141 }
 142 EXPORT_SYMBOL(sun4v_hvapi_unregister);
 143
 144 int sun4v_hvapi_get(unsigned long group,
 145                     unsigned long *major,
 146                     unsigned long *minor)
 147 {
 148         struct api_info *p;
 149         unsigned long flags;
 150         int ret;
 151
 152         spin_lock_irqsave(&hvapi_lock, flags);
 153         ret = -EINVAL;
 154         p = __get_info(group);
 155         if (p && p->refcnt) {
 156                 *major = p->major;
 157                 *minor = p->minor;
 158                 ret = 0;
 159         }
 160         spin_unlock_irqrestore(&hvapi_lock, flags);
 161
 162         return ret;
 163 }
 164 EXPORT_SYMBOL(sun4v_hvapi_get);
 165
 166 void __init sun4v_hvapi_init(void)
 167 {
 168         unsigned long group, major, minor;
 169
 170         group = HV_GRP_SUN4V;
 171         major = 1;
 172         minor = 0;
 173         if (sun4v_hvapi_register(group, major, &minor))
 174                 goto bad;
 175
 176         group = HV_GRP_CORE;
 177         major = 1;
 178         minor = 1;
 179         if (sun4v_hvapi_register(group, major, &minor))
 180                 goto bad;
 181
 182         return;
 183
 184 bad:
 185         prom_printf("HVAPI: Cannot register API group "
 186                     "%lx with major(%u) minor(%u)\n",
 187                     group, major, minor);
 188         prom_halt();
 189 }