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   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/module.h>
   7 #include <linux/init.h>
   8 #include <linux/slab.h>
   9
  10 #include <asm/hypervisor.h>
  11 #include <asm/oplib.h>
  12 #include <asm/sstate.h>
  13
  14 /* If the hypervisor indicates that the API setting
  15  * calls are unsupported, by returning HV_EBADTRAP or
  16  * HV_ENOTSUPPORTED, we assume that API groups with the
  17  * PRE_API flag set are major 1 minor 0.
  18  */
  19 struct api_info {
  20         unsigned long group;
  21         unsigned long major;
  22         unsigned long minor;
  23         unsigned int refcnt;
  24         unsigned int flags;
  25 #define FLAG_PRE_API            0x00000001
  26 };
  27
  28 static struct api_info api_table[] = {
  29         { .group = HV_GRP_SUN4V,        .flags = FLAG_PRE_API   },
  30         { .group = HV_GRP_CORE,         .flags = FLAG_PRE_API   },
  31         { .group = HV_GRP_INTR,                                 },
  32         { .group = HV_GRP_SOFT_STATE,                           },
  33         { .group = HV_GRP_PCI,          .flags = FLAG_PRE_API   },
  34         { .group = HV_GRP_LDOM,                                 },
  35         { .group = HV_GRP_SVC_CHAN,     .flags = FLAG_PRE_API   },
  36         { .group = HV_GRP_NCS,          .flags = FLAG_PRE_API   },
  37         { .group = HV_GRP_RNG,                                  },
  38         { .group = HV_GRP_NIAG_PERF,    .flags = FLAG_PRE_API   },
  39         { .group = HV_GRP_FIRE_PERF,                            },
  40         { .group = HV_GRP_N2_CPU,                               },
  41         { .group = HV_GRP_NIU,                                  },
  42         { .group = HV_GRP_VF_CPU,                               },
  43         { .group = HV_GRP_DIAG,         .flags = FLAG_PRE_API   },
  44 };
  45
  46 static DEFINE_SPINLOCK(hvapi_lock);
  47
  48 static struct api_info *__get_info(unsigned long group)
  49 {
  50         int i;
  51
  52         for (i = 0; i < ARRAY_SIZE(api_table); i++) {
  53                 if (api_table[i].group == group)
  54                         return &api_table[i];
  55         }
  56         return NULL;
  57 }
  58
  59 static void __get_ref(struct api_info *p)
  60 {
  61         p->refcnt++;
  62 }
  63
  64 static void __put_ref(struct api_info *p)
  65 {
  66         if (--p->refcnt == 0) {
  67                 unsigned long ignore;
  68
  69                 sun4v_set_version(p->group, 0, 0, &ignore);
  70                 p->major = p->minor = 0;
  71         }
  72 }
  73
  74 /* Register a hypervisor API specification.  It indicates the
  75  * API group and desired major+minor.
  76  *
  77  * If an existing API registration exists '0' (success) will
  78  * be returned if it is compatible with the one being registered.
  79  * Otherwise a negative error code will be returned.
  80  *
  81  * Otherwise an attempt will be made to negotiate the requested
  82  * API group/major/minor with the hypervisor, and errors returned
  83  * if that does not succeed.
  84  */
  85 int sun4v_hvapi_register(unsigned long group, unsigned long major,
  86                          unsigned long *minor)
  87 {
  88         struct api_info *p;
  89         unsigned long flags;
  90         int ret;
  91
  92         spin_lock_irqsave(&hvapi_lock, flags);
  93         p = __get_info(group);
  94         ret = -EINVAL;
  95         if (p) {
  96                 if (p->refcnt) {
  97                         ret = -EINVAL;
  98                         if (p->major == major) {
  99                                 *minor = p->minor;
 100                                 ret = 0;
 101                         }
 102                 } else {
 103                         unsigned long actual_minor;
 104                         unsigned long hv_ret;
 105
 106                         hv_ret = sun4v_set_version(group, major, *minor,
 107                                                    &actual_minor);
 108                         ret = -EINVAL;
 109                         if (hv_ret == HV_EOK) {
 110                                 *minor = actual_minor;
 111                                 p->major = major;
 112                                 p->minor = actual_minor;
 113                                 ret = 0;
 114                         } else if (hv_ret == HV_EBADTRAP ||
 115                                    hv_ret == HV_ENOTSUPPORTED) {
 116                                 if (p->flags & FLAG_PRE_API) {
 117                                         if (major == 1) {
 118                                                 p->major = 1;
 119                                                 p->minor = 0;
 120                                                 *minor = 0;
 121                                                 ret = 0;
 122                                         }
 123                                 }
 124                         }
 125                 }
 126
 127                 if (ret == 0)
 128                         __get_ref(p);
 129         }
 130         spin_unlock_irqrestore(&hvapi_lock, flags);
 131
 132         return ret;
 133 }
 134 EXPORT_SYMBOL(sun4v_hvapi_register);
 135
 136 void sun4v_hvapi_unregister(unsigned long group)
 137 {
 138         struct api_info *p;
 139         unsigned long flags;
 140
 141         spin_lock_irqsave(&hvapi_lock, flags);
 142         p = __get_info(group);
 143         if (p)
 144                 __put_ref(p);
 145         spin_unlock_irqrestore(&hvapi_lock, flags);
 146 }
 147 EXPORT_SYMBOL(sun4v_hvapi_unregister);
 148
 149 int sun4v_hvapi_get(unsigned long group,
 150                     unsigned long *major,
 151                     unsigned long *minor)
 152 {
 153         struct api_info *p;
 154         unsigned long flags;
 155         int ret;
 156
 157         spin_lock_irqsave(&hvapi_lock, flags);
 158         ret = -EINVAL;
 159         p = __get_info(group);
 160         if (p && p->refcnt) {
 161                 *major = p->major;
 162                 *minor = p->minor;
 163                 ret = 0;
 164         }
 165         spin_unlock_irqrestore(&hvapi_lock, flags);
 166
 167         return ret;
 168 }
 169 EXPORT_SYMBOL(sun4v_hvapi_get);
 170
 171 void __init sun4v_hvapi_init(void)
 172 {
 173         unsigned long group, major, minor;
 174
 175         group = HV_GRP_SUN4V;
 176         major = 1;
 177         minor = 0;
 178         if (sun4v_hvapi_register(group, major, &minor))
 179                 goto bad;
 180
 181         group = HV_GRP_CORE;
 182         major = 1;
 183         minor = 1;
 184         if (sun4v_hvapi_register(group, major, &minor))
 185                 goto bad;
 186
 187         sun4v_sstate_init();
 188
 189         return;
 190
 191 bad:
 192         prom_printf("HVAPI: Cannot register API group "
 193                     "%lx with major(%u) minor(%u)\n",
 194                     group, major, minor);
 195         prom_halt();
 196 }