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