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/export.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_TM,                                   },
  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_RNG,                                  },
  37         { .group = HV_GRP_PBOOT,                                },
  38         { .group = HV_GRP_TPM,                                  },
  39         { .group = HV_GRP_SDIO,                                 },
  40         { .group = HV_GRP_SDIO_ERR,                             },
  41         { .group = HV_GRP_REBOOT_DATA,                          },
  42         { .group = HV_GRP_NIAG_PERF,    .flags = FLAG_PRE_API   },
  43         { .group = HV_GRP_FIRE_PERF,                            },
  44         { .group = HV_GRP_N2_CPU,                               },
  45         { .group = HV_GRP_NIU,                                  },
  46         { .group = HV_GRP_VF_CPU,                               },
  47         { .group = HV_GRP_KT_CPU,                               },
  48         { .group = HV_GRP_VT_CPU,                               },
  49         { .group = HV_GRP_DIAG,         .flags = FLAG_PRE_API   },
  50 };
  51
  52 static DEFINE_SPINLOCK(hvapi_lock);
  53
  54 static struct api_info *__get_info(unsigned long group)
  55 {
  56         int i;
  57
  58         for (i = 0; i < ARRAY_SIZE(api_table); i++) {
  59                 if (api_table[i].group == group)
  60                         return &api_table[i];
  61         }
  62         return NULL;
  63 }
  64
  65 static void __get_ref(struct api_info *p)
  66 {
  67         p->refcnt++;
  68 }
  69
  70 static void __put_ref(struct api_info *p)
  71 {
  72         if (--p->refcnt == 0) {
  73                 unsigned long ignore;
  74
  75                 sun4v_set_version(p->group, 0, 0, &ignore);
  76                 p->major = p->minor = 0;
  77         }
  78 }
  79
  80 /* Register a hypervisor API specification.  It indicates the
  81  * API group and desired major+minor.
  82  *
  83  * If an existing API registration exists '0' (success) will
  84  * be returned if it is compatible with the one being registered.
  85  * Otherwise a negative error code will be returned.
  86  *
  87  * Otherwise an attempt will be made to negotiate the requested
  88  * API group/major/minor with the hypervisor, and errors returned
  89  * if that does not succeed.
  90  */
  91 int sun4v_hvapi_register(unsigned long group, unsigned long major,
  92                          unsigned long *minor)
  93 {
  94         struct api_info *p;
  95         unsigned long flags;
  96         int ret;
  97
  98         spin_lock_irqsave(&hvapi_lock, flags);
  99         p = __get_info(group);
 100         ret = -EINVAL;
 101         if (p) {
 102                 if (p->refcnt) {
 103                         ret = -EINVAL;
 104                         if (p->major == major) {
 105                                 *minor = p->minor;
 106                                 ret = 0;
 107                         }
 108                 } else {
 109                         unsigned long actual_minor;
 110                         unsigned long hv_ret;
 111
 112                         hv_ret = sun4v_set_version(group, major, *minor,
 113                                                    &actual_minor);
 114                         ret = -EINVAL;
 115                         if (hv_ret == HV_EOK) {
 116                                 *minor = actual_minor;
 117                                 p->major = major;
 118                                 p->minor = actual_minor;
 119                                 ret = 0;
 120                         } else if (hv_ret == HV_EBADTRAP ||
 121                                    hv_ret == HV_ENOTSUPPORTED) {
 122                                 if (p->flags & FLAG_PRE_API) {
 123                                         if (major == 1) {
 124                                                 p->major = 1;
 125                                                 p->minor = 0;
 126                                                 *minor = 0;
 127                                                 ret = 0;
 128                                         }
 129                                 }
 130                         }
 131                 }
 132
 133                 if (ret == 0)
 134                         __get_ref(p);
 135         }
 136         spin_unlock_irqrestore(&hvapi_lock, flags);
 137
 138         return ret;
 139 }
 140 EXPORT_SYMBOL(sun4v_hvapi_register);
 141
 142 void sun4v_hvapi_unregister(unsigned long group)
 143 {
 144         struct api_info *p;
 145         unsigned long flags;
 146
 147         spin_lock_irqsave(&hvapi_lock, flags);
 148         p = __get_info(group);
 149         if (p)
 150                 __put_ref(p);
 151         spin_unlock_irqrestore(&hvapi_lock, flags);
 152 }
 153 EXPORT_SYMBOL(sun4v_hvapi_unregister);
 154
 155 int sun4v_hvapi_get(unsigned long group,
 156                     unsigned long *major,
 157                     unsigned long *minor)
 158 {
 159         struct api_info *p;
 160         unsigned long flags;
 161         int ret;
 162
 163         spin_lock_irqsave(&hvapi_lock, flags);
 164         ret = -EINVAL;
 165         p = __get_info(group);
 166         if (p && p->refcnt) {
 167                 *major = p->major;
 168                 *minor = p->minor;
 169                 ret = 0;
 170         }
 171         spin_unlock_irqrestore(&hvapi_lock, flags);
 172
 173         return ret;
 174 }
 175 EXPORT_SYMBOL(sun4v_hvapi_get);
 176
 177 void __init sun4v_hvapi_init(void)
 178 {
 179         unsigned long group, major, minor;
 180
 181         group = HV_GRP_SUN4V;
 182         major = 1;
 183         minor = 0;
 184         if (sun4v_hvapi_register(group, major, &minor))
 185                 goto bad;
 186
 187         group = HV_GRP_CORE;
 188         major = 1;
 189         minor = 1;
 190         if (sun4v_hvapi_register(group, major, &minor))
 191                 goto bad;
 192
 193         return;
 194
 195 bad:
 196         prom_printf("HVAPI: Cannot register API group "
 197                     "%lx with major(%lu) minor(%lu)\n",
 198                     group, major, minor);
 199         prom_halt();
 200 }