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         { .group = HV_GRP_M7_PERF,                              },
  52 };
  53
  54 static DEFINE_SPINLOCK(hvapi_lock);
  55
  56 static struct api_info *__get_info(unsigned long group)
  57 {
  58         int i;
  59
  60         for (i = 0; i < ARRAY_SIZE(api_table); i++) {
  61                 if (api_table[i].group == group)
  62                         return &api_table[i];
  63         }
  64         return NULL;
  65 }
  66
  67 static void __get_ref(struct api_info *p)
  68 {
  69         p->refcnt++;
  70 }
  71
  72 static void __put_ref(struct api_info *p)
  73 {
  74         if (--p->refcnt == 0) {
  75                 unsigned long ignore;
  76
  77                 sun4v_set_version(p->group, 0, 0, &ignore);
  78                 p->major = p->minor = 0;
  79         }
  80 }
  81
  82 /* Register a hypervisor API specification.  It indicates the
  83  * API group and desired major+minor.
  84  *
  85  * If an existing API registration exists '0' (success) will
  86  * be returned if it is compatible with the one being registered.
  87  * Otherwise a negative error code will be returned.
  88  *
  89  * Otherwise an attempt will be made to negotiate the requested
  90  * API group/major/minor with the hypervisor, and errors returned
  91  * if that does not succeed.
  92  */
  93 int sun4v_hvapi_register(unsigned long group, unsigned long major,
  94                          unsigned long *minor)
  95 {
  96         struct api_info *p;
  97         unsigned long flags;
  98         int ret;
  99
 100         spin_lock_irqsave(&hvapi_lock, flags);
 101         p = __get_info(group);
 102         ret = -EINVAL;
 103         if (p) {
 104                 if (p->refcnt) {
 105                         ret = -EINVAL;
 106                         if (p->major == major) {
 107                                 *minor = p->minor;
 108                                 ret = 0;
 109                         }
 110                 } else {
 111                         unsigned long actual_minor;
 112                         unsigned long hv_ret;
 113
 114                         hv_ret = sun4v_set_version(group, major, *minor,
 115                                                    &actual_minor);
 116                         ret = -EINVAL;
 117                         if (hv_ret == HV_EOK) {
 118                                 *minor = actual_minor;
 119                                 p->major = major;
 120                                 p->minor = actual_minor;
 121                                 ret = 0;
 122                         } else if (hv_ret == HV_EBADTRAP ||
 123                                    hv_ret == HV_ENOTSUPPORTED) {
 124                                 if (p->flags & FLAG_PRE_API) {
 125                                         if (major == 1) {
 126                                                 p->major = 1;
 127                                                 p->minor = 0;
 128                                                 *minor = 0;
 129                                                 ret = 0;
 130                                         }
 131                                 }
 132                         }
 133                 }
 134
 135                 if (ret == 0)
 136                         __get_ref(p);
 137         }
 138         spin_unlock_irqrestore(&hvapi_lock, flags);
 139
 140         return ret;
 141 }
 142 EXPORT_SYMBOL(sun4v_hvapi_register);
 143
 144 void sun4v_hvapi_unregister(unsigned long group)
 145 {
 146         struct api_info *p;
 147         unsigned long flags;
 148
 149         spin_lock_irqsave(&hvapi_lock, flags);
 150         p = __get_info(group);
 151         if (p)
 152                 __put_ref(p);
 153         spin_unlock_irqrestore(&hvapi_lock, flags);
 154 }
 155 EXPORT_SYMBOL(sun4v_hvapi_unregister);
 156
 157 int sun4v_hvapi_get(unsigned long group,
 158                     unsigned long *major,
 159                     unsigned long *minor)
 160 {
 161         struct api_info *p;
 162         unsigned long flags;
 163         int ret;
 164
 165         spin_lock_irqsave(&hvapi_lock, flags);
 166         ret = -EINVAL;
 167         p = __get_info(group);
 168         if (p && p->refcnt) {
 169                 *major = p->major;
 170                 *minor = p->minor;
 171                 ret = 0;
 172         }
 173         spin_unlock_irqrestore(&hvapi_lock, flags);
 174
 175         return ret;
 176 }
 177 EXPORT_SYMBOL(sun4v_hvapi_get);
 178
 179 void __init sun4v_hvapi_init(void)
 180 {
 181         unsigned long group, major, minor;
 182
 183         group = HV_GRP_SUN4V;
 184         major = 1;
 185         minor = 0;
 186         if (sun4v_hvapi_register(group, major, &minor))
 187                 goto bad;
 188
 189         group = HV_GRP_CORE;
 190         major = 1;
 191         minor = 1;
 192         if (sun4v_hvapi_register(group, major, &minor))
 193                 goto bad;
 194
 195         return;
 196
 197 bad:
 198         prom_printf("HVAPI: Cannot register API group "
 199                     "%lx with major(%lu) minor(%lu)\n",
 200                     group, major, minor);
 201         prom_halt();
 202 }