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_T5_CPU,                               },
  50         { .group = HV_GRP_DIAG,         .flags = FLAG_PRE_API   },
  51 };
  52
  53 static DEFINE_SPINLOCK(hvapi_lock);
  54
  55 static struct api_info *__get_info(unsigned long group)
  56 {
  57         int i;
  58
  59         for (i = 0; i < ARRAY_SIZE(api_table); i++) {
  60                 if (api_table[i].group == group)
  61                         return &api_table[i];
  62         }
  63         return NULL;
  64 }
  65
  66 static void __get_ref(struct api_info *p)
  67 {
  68         p->refcnt++;
  69 }
  70
  71 static void __put_ref(struct api_info *p)
  72 {
  73         if (--p->refcnt == 0) {
  74                 unsigned long ignore;
  75
  76                 sun4v_set_version(p->group, 0, 0, &ignore);
  77                 p->major = p->minor = 0;
  78         }
  79 }
  80
  81 /* Register a hypervisor API specification.  It indicates the
  82  * API group and desired major+minor.
  83  *
  84  * If an existing API registration exists '0' (success) will
  85  * be returned if it is compatible with the one being registered.
  86  * Otherwise a negative error code will be returned.
  87  *
  88  * Otherwise an attempt will be made to negotiate the requested
  89  * API group/major/minor with the hypervisor, and errors returned
  90  * if that does not succeed.
  91  */
  92 int sun4v_hvapi_register(unsigned long group, unsigned long major,
  93                          unsigned long *minor)
  94 {
  95         struct api_info *p;
  96         unsigned long flags;
  97         int ret;
  98
  99         spin_lock_irqsave(&hvapi_lock, flags);
 100         p = __get_info(group);
 101         ret = -EINVAL;
 102         if (p) {
 103                 if (p->refcnt) {
 104                         ret = -EINVAL;
 105                         if (p->major == major) {
 106                                 *minor = p->minor;
 107                                 ret = 0;
 108                         }
 109                 } else {
 110                         unsigned long actual_minor;
 111                         unsigned long hv_ret;
 112
 113                         hv_ret = sun4v_set_version(group, major, *minor,
 114                                                    &actual_minor);
 115                         ret = -EINVAL;
 116                         if (hv_ret == HV_EOK) {
 117                                 *minor = actual_minor;
 118                                 p->major = major;
 119                                 p->minor = actual_minor;
 120                                 ret = 0;
 121                         } else if (hv_ret == HV_EBADTRAP ||
 122                                    hv_ret == HV_ENOTSUPPORTED) {
 123                                 if (p->flags & FLAG_PRE_API) {
 124                                         if (major == 1) {
 125                                                 p->major = 1;
 126                                                 p->minor = 0;
 127                                                 *minor = 0;
 128                                                 ret = 0;
 129                                         }
 130                                 }
 131                         }
 132                 }
 133
 134                 if (ret == 0)
 135                         __get_ref(p);
 136         }
 137         spin_unlock_irqrestore(&hvapi_lock, flags);
 138
 139         return ret;
 140 }
 141 EXPORT_SYMBOL(sun4v_hvapi_register);
 142
 143 void sun4v_hvapi_unregister(unsigned long group)
 144 {
 145         struct api_info *p;
 146         unsigned long flags;
 147
 148         spin_lock_irqsave(&hvapi_lock, flags);
 149         p = __get_info(group);
 150         if (p)
 151                 __put_ref(p);
 152         spin_unlock_irqrestore(&hvapi_lock, flags);
 153 }
 154 EXPORT_SYMBOL(sun4v_hvapi_unregister);
 155
 156 int sun4v_hvapi_get(unsigned long group,
 157                     unsigned long *major,
 158                     unsigned long *minor)
 159 {
 160         struct api_info *p;
 161         unsigned long flags;
 162         int ret;
 163
 164         spin_lock_irqsave(&hvapi_lock, flags);
 165         ret = -EINVAL;
 166         p = __get_info(group);
 167         if (p && p->refcnt) {
 168                 *major = p->major;
 169                 *minor = p->minor;
 170                 ret = 0;
 171         }
 172         spin_unlock_irqrestore(&hvapi_lock, flags);
 173
 174         return ret;
 175 }
 176 EXPORT_SYMBOL(sun4v_hvapi_get);
 177
 178 void __init sun4v_hvapi_init(void)
 179 {
 180         unsigned long group, major, minor;
 181
 182         group = HV_GRP_SUN4V;
 183         major = 1;
 184         minor = 0;
 185         if (sun4v_hvapi_register(group, major, &minor))
 186                 goto bad;
 187
 188         group = HV_GRP_CORE;
 189         major = 1;
 190         minor = 1;
 191         if (sun4v_hvapi_register(group, major, &minor))
 192                 goto bad;
 193
 194         return;
 195
 196 bad:
 197         prom_printf("HVAPI: Cannot register API group "
 198                     "%lx with major(%lu) minor(%lu)\n",
 199                     group, major, minor);
 200         prom_halt();
 201 }