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