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