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