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_ATU,          .flags = FLAG_PRE_API   },
  43         { .group = HV_GRP_NIAG_PERF,    .flags = FLAG_PRE_API   },
  44         { .group = HV_GRP_FIRE_PERF,                            },
  45         { .group = HV_GRP_N2_CPU,                               },
  46         { .group = HV_GRP_NIU,                                  },
  47         { .group = HV_GRP_VF_CPU,                               },
  48         { .group = HV_GRP_KT_CPU,                               },
  49         { .group = HV_GRP_VT_CPU,                               },
  50         { .group = HV_GRP_T5_CPU,                               },
  51         { .group = HV_GRP_DIAG,         .flags = FLAG_PRE_API   },
  52         { .group = HV_GRP_M7_PERF,                              },
  53 };
  54
  55 static DEFINE_SPINLOCK(hvapi_lock);
  56
  57 static struct api_info *__get_info(unsigned long group)
  58 {
  59         int i;
  60
  61         for (i = 0; i < ARRAY_SIZE(api_table); i++) {
  62                 if (api_table[i].group == group)
  63                         return &api_table[i];
  64         }
  65         return NULL;
  66 }
  67
  68 static void __get_ref(struct api_info *p)
  69 {
  70         p->refcnt++;
  71 }
  72
  73 static void __put_ref(struct api_info *p)
  74 {
  75         if (--p->refcnt == 0) {
  76                 unsigned long ignore;
  77
  78                 sun4v_set_version(p->group, 0, 0, &ignore);
  79                 p->major = p->minor = 0;
  80         }
  81 }
  82
  83 /* Register a hypervisor API specification.  It indicates the
  84  * API group and desired major+minor.
  85  *
  86  * If an existing API registration exists '0' (success) will
  87  * be returned if it is compatible with the one being registered.
  88  * Otherwise a negative error code will be returned.
  89  *
  90  * Otherwise an attempt will be made to negotiate the requested
  91  * API group/major/minor with the hypervisor, and errors returned
  92  * if that does not succeed.
  93  */
  94 int sun4v_hvapi_register(unsigned long group, unsigned long major,
  95                          unsigned long *minor)
  96 {
  97         struct api_info *p;
  98         unsigned long flags;
  99         int ret;
 100
 101         spin_lock_irqsave(&hvapi_lock, flags);
 102         p = __get_info(group);
 103         ret = -EINVAL;
 104         if (p) {
 105                 if (p->refcnt) {
 106                         ret = -EINVAL;
 107                         if (p->major == major) {
 108                                 *minor = p->minor;
 109                                 ret = 0;
 110                         }
 111                 } else {
 112                         unsigned long actual_minor;
 113                         unsigned long hv_ret;
 114
 115                         hv_ret = sun4v_set_version(group, major, *minor,
 116                                                    &actual_minor);
 117                         ret = -EINVAL;
 118                         if (hv_ret == HV_EOK) {
 119                                 *minor = actual_minor;
 120                                 p->major = major;
 121                                 p->minor = actual_minor;
 122                                 ret = 0;
 123                         } else if (hv_ret == HV_EBADTRAP ||
 124                                    hv_ret == HV_ENOTSUPPORTED) {
 125                                 if (p->flags & FLAG_PRE_API) {
 126                                         if (major == 1) {
 127                                                 p->major = 1;
 128                                                 p->minor = 0;
 129                                                 *minor = 0;
 130                                                 ret = 0;
 131                                         }
 132                                 }
 133                         }
 134                 }
 135
 136                 if (ret == 0)
 137                         __get_ref(p);
 138         }
 139         spin_unlock_irqrestore(&hvapi_lock, flags);
 140
 141         return ret;
 142 }
 143 EXPORT_SYMBOL(sun4v_hvapi_register);
 144
 145 void sun4v_hvapi_unregister(unsigned long group)
 146 {
 147         struct api_info *p;
 148         unsigned long flags;
 149
 150         spin_lock_irqsave(&hvapi_lock, flags);
 151         p = __get_info(group);
 152         if (p)
 153                 __put_ref(p);
 154         spin_unlock_irqrestore(&hvapi_lock, flags);
 155 }
 156 EXPORT_SYMBOL(sun4v_hvapi_unregister);
 157
 158 int sun4v_hvapi_get(unsigned long group,
 159                     unsigned long *major,
 160                     unsigned long *minor)
 161 {
 162         struct api_info *p;
 163         unsigned long flags;
 164         int ret;
 165
 166         spin_lock_irqsave(&hvapi_lock, flags);
 167         ret = -EINVAL;
 168         p = __get_info(group);
 169         if (p && p->refcnt) {
 170                 *major = p->major;
 171                 *minor = p->minor;
 172                 ret = 0;
 173         }
 174         spin_unlock_irqrestore(&hvapi_lock, flags);
 175
 176         return ret;
 177 }
 178 EXPORT_SYMBOL(sun4v_hvapi_get);
 179
 180 void __init sun4v_hvapi_init(void)
 181 {
 182         unsigned long group, major, minor;
 183
 184         group = HV_GRP_SUN4V;
 185         major = 1;
 186         minor = 0;
 187         if (sun4v_hvapi_register(group, major, &minor))
 188                 goto bad;
 189
 190         group = HV_GRP_CORE;
 191         major = 1;
 192         minor = 1;
 193         if (sun4v_hvapi_register(group, major, &minor))
 194                 goto bad;
 195
 196         return;
 197
 198 bad:
 199         prom_printf("HVAPI: Cannot register API group "
 200                     "%lx with major(%lu) minor(%lu)\n",
 201                     group, major, minor);
 202         prom_halt();
 203 }