Merge branch 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6] / arch / sparc64 / 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/module.h>
7 #include <linux/init.h>
8 #include <linux/slab.h>
9
10 #include <asm/hypervisor.h>
11 #include <asm/oplib.h>
12
13 /* If the hypervisor indicates that the API setting
14  * calls are unsupported, by returning HV_EBADTRAP or
15  * HV_ENOTSUPPORTED, we assume that API groups with the
16  * PRE_API flag set are major 1 minor 0.
17  */
18 struct api_info {
19         unsigned long group;
20         unsigned long major;
21         unsigned long minor;
22         unsigned int refcnt;
23         unsigned int flags;
24 #define FLAG_PRE_API            0x00000001
25 };
26
27 static struct api_info api_table[] = {
28         { .group = HV_GRP_SUN4V,        .flags = FLAG_PRE_API   },
29         { .group = HV_GRP_CORE,         .flags = FLAG_PRE_API   },
30         { .group = HV_GRP_INTR,                                 },
31         { .group = HV_GRP_SOFT_STATE,                           },
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_NIAG_PERF,    .flags = FLAG_PRE_API   },
38         { .group = HV_GRP_FIRE_PERF,                            },
39         { .group = HV_GRP_N2_CPU,                               },
40         { .group = HV_GRP_NIU,                                  },
41         { .group = HV_GRP_VF_CPU,                               },
42         { .group = HV_GRP_DIAG,         .flags = FLAG_PRE_API   },
43 };
44
45 static DEFINE_SPINLOCK(hvapi_lock);
46
47 static struct api_info *__get_info(unsigned long group)
48 {
49         int i;
50
51         for (i = 0; i < ARRAY_SIZE(api_table); i++) {
52                 if (api_table[i].group == group)
53                         return &api_table[i];
54         }
55         return NULL;
56 }
57
58 static void __get_ref(struct api_info *p)
59 {
60         p->refcnt++;
61 }
62
63 static void __put_ref(struct api_info *p)
64 {
65         if (--p->refcnt == 0) {
66                 unsigned long ignore;
67
68                 sun4v_set_version(p->group, 0, 0, &ignore);
69                 p->major = p->minor = 0;
70         }
71 }
72
73 /* Register a hypervisor API specification.  It indicates the
74  * API group and desired major+minor.
75  *
76  * If an existing API registration exists '0' (success) will
77  * be returned if it is compatible with the one being registered.
78  * Otherwise a negative error code will be returned.
79  *
80  * Otherwise an attempt will be made to negotiate the requested
81  * API group/major/minor with the hypervisor, and errors returned
82  * if that does not succeed.
83  */
84 int sun4v_hvapi_register(unsigned long group, unsigned long major,
85                          unsigned long *minor)
86 {
87         struct api_info *p;
88         unsigned long flags;
89         int ret;
90
91         spin_lock_irqsave(&hvapi_lock, flags);
92         p = __get_info(group);
93         ret = -EINVAL;
94         if (p) {
95                 if (p->refcnt) {
96                         ret = -EINVAL;
97                         if (p->major == major) {
98                                 *minor = p->minor;
99                                 ret = 0;
100                         }
101                 } else {
102                         unsigned long actual_minor;
103                         unsigned long hv_ret;
104
105                         hv_ret = sun4v_set_version(group, major, *minor,
106                                                    &actual_minor);
107                         ret = -EINVAL;
108                         if (hv_ret == HV_EOK) {
109                                 *minor = actual_minor;
110                                 p->major = major;
111                                 p->minor = actual_minor;
112                                 ret = 0;
113                         } else if (hv_ret == HV_EBADTRAP ||
114                                    hv_ret == HV_ENOTSUPPORTED) {
115                                 if (p->flags & FLAG_PRE_API) {
116                                         if (major == 1) {
117                                                 p->major = 1;
118                                                 p->minor = 0;
119                                                 *minor = 0;
120                                                 ret = 0;
121                                         }
122                                 }
123                         }
124                 }
125
126                 if (ret == 0)
127                         __get_ref(p);
128         }
129         spin_unlock_irqrestore(&hvapi_lock, flags);
130
131         return ret;
132 }
133 EXPORT_SYMBOL(sun4v_hvapi_register);
134
135 void sun4v_hvapi_unregister(unsigned long group)
136 {
137         struct api_info *p;
138         unsigned long flags;
139
140         spin_lock_irqsave(&hvapi_lock, flags);
141         p = __get_info(group);
142         if (p)
143                 __put_ref(p);
144         spin_unlock_irqrestore(&hvapi_lock, flags);
145 }
146 EXPORT_SYMBOL(sun4v_hvapi_unregister);
147
148 int sun4v_hvapi_get(unsigned long group,
149                     unsigned long *major,
150                     unsigned long *minor)
151 {
152         struct api_info *p;
153         unsigned long flags;
154         int ret;
155
156         spin_lock_irqsave(&hvapi_lock, flags);
157         ret = -EINVAL;
158         p = __get_info(group);
159         if (p && p->refcnt) {
160                 *major = p->major;
161                 *minor = p->minor;
162                 ret = 0;
163         }
164         spin_unlock_irqrestore(&hvapi_lock, flags);
165
166         return ret;
167 }
168 EXPORT_SYMBOL(sun4v_hvapi_get);
169
170 void __init sun4v_hvapi_init(void)
171 {
172         unsigned long group, major, minor;
173
174         group = HV_GRP_SUN4V;
175         major = 1;
176         minor = 0;
177         if (sun4v_hvapi_register(group, major, &minor))
178                 goto bad;
179
180         group = HV_GRP_CORE;
181         major = 1;
182         minor = 1;
183         if (sun4v_hvapi_register(group, major, &minor))
184                 goto bad;
185
186         return;
187
188 bad:
189         prom_printf("HVAPI: Cannot register API group "
190                     "%lx with major(%u) minor(%u)\n",
191                     group, major, minor);
192         prom_halt();
193 }