1 // SPDX-License-Identifier: GPL-2.0
2 /* hvapi.c: Hypervisor API management.
3 *
4 * Copyright (C) 2007 David S. Miller <davem@davemloft.net>
5 */
6 #include <linux/kernel.h>
7 #include <linux/export.h>
8 #include <linux/init.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_TM, },
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_PBOOT, },
39 { .group = HV_GRP_TPM, },
40 { .group = HV_GRP_SDIO, },
41 { .group = HV_GRP_SDIO_ERR, },
42 { .group = HV_GRP_REBOOT_DATA, },
43 { .group = HV_GRP_ATU, .flags = FLAG_PRE_API },
44 { .group = HV_GRP_NIAG_PERF, .flags = FLAG_PRE_API },
45 { .group = HV_GRP_FIRE_PERF, },
46 { .group = HV_GRP_N2_CPU, },
47 { .group = HV_GRP_NIU, },
48 { .group = HV_GRP_VF_CPU, },
49 { .group = HV_GRP_KT_CPU, },
50 { .group = HV_GRP_VT_CPU, },
51 { .group = HV_GRP_T5_CPU, },
52 { .group = HV_GRP_DIAG, .flags = FLAG_PRE_API },
53 { .group = HV_GRP_M7_PERF, },
54 };
55
56 static DEFINE_SPINLOCK(hvapi_lock);
57
__get_info(unsigned long group)58 static struct api_info *__get_info(unsigned long group)
59 {
60 int i;
61
62 for (i = 0; i < ARRAY_SIZE(api_table); i++) {
63 if (api_table[i].group == group)
64 return &api_table[i];
65 }
66 return NULL;
67 }
68
__get_ref(struct api_info * p)69 static void __get_ref(struct api_info *p)
70 {
71 p->refcnt++;
72 }
73
__put_ref(struct api_info * p)74 static void __put_ref(struct api_info *p)
75 {
76 if (--p->refcnt == 0) {
77 unsigned long ignore;
78
79 sun4v_set_version(p->group, 0, 0, &ignore);
80 p->major = p->minor = 0;
81 }
82 }
83
84 /* Register a hypervisor API specification. It indicates the
85 * API group and desired major+minor.
86 *
87 * If an existing API registration exists '0' (success) will
88 * be returned if it is compatible with the one being registered.
89 * Otherwise a negative error code will be returned.
90 *
91 * Otherwise an attempt will be made to negotiate the requested
92 * API group/major/minor with the hypervisor, and errors returned
93 * if that does not succeed.
94 */
sun4v_hvapi_register(unsigned long group,unsigned long major,unsigned long * minor)95 int sun4v_hvapi_register(unsigned long group, unsigned long major,
96 unsigned long *minor)
97 {
98 struct api_info *p;
99 unsigned long flags;
100 int ret;
101
102 spin_lock_irqsave(&hvapi_lock, flags);
103 p = __get_info(group);
104 ret = -EINVAL;
105 if (p) {
106 if (p->refcnt) {
107 ret = -EINVAL;
108 if (p->major == major) {
109 *minor = p->minor;
110 ret = 0;
111 }
112 } else {
113 unsigned long actual_minor;
114 unsigned long hv_ret;
115
116 hv_ret = sun4v_set_version(group, major, *minor,
117 &actual_minor);
118 ret = -EINVAL;
119 if (hv_ret == HV_EOK) {
120 *minor = actual_minor;
121 p->major = major;
122 p->minor = actual_minor;
123 ret = 0;
124 } else if (hv_ret == HV_EBADTRAP ||
125 hv_ret == HV_ENOTSUPPORTED) {
126 if (p->flags & FLAG_PRE_API) {
127 if (major == 1) {
128 p->major = 1;
129 p->minor = 0;
130 *minor = 0;
131 ret = 0;
132 }
133 }
134 }
135 }
136
137 if (ret == 0)
138 __get_ref(p);
139 }
140 spin_unlock_irqrestore(&hvapi_lock, flags);
141
142 return ret;
143 }
144 EXPORT_SYMBOL(sun4v_hvapi_register);
145
sun4v_hvapi_unregister(unsigned long group)146 void sun4v_hvapi_unregister(unsigned long group)
147 {
148 struct api_info *p;
149 unsigned long flags;
150
151 spin_lock_irqsave(&hvapi_lock, flags);
152 p = __get_info(group);
153 if (p)
154 __put_ref(p);
155 spin_unlock_irqrestore(&hvapi_lock, flags);
156 }
157 EXPORT_SYMBOL(sun4v_hvapi_unregister);
158
sun4v_hvapi_get(unsigned long group,unsigned long * major,unsigned long * minor)159 int sun4v_hvapi_get(unsigned long group,
160 unsigned long *major,
161 unsigned long *minor)
162 {
163 struct api_info *p;
164 unsigned long flags;
165 int ret;
166
167 spin_lock_irqsave(&hvapi_lock, flags);
168 ret = -EINVAL;
169 p = __get_info(group);
170 if (p && p->refcnt) {
171 *major = p->major;
172 *minor = p->minor;
173 ret = 0;
174 }
175 spin_unlock_irqrestore(&hvapi_lock, flags);
176
177 return ret;
178 }
179 EXPORT_SYMBOL(sun4v_hvapi_get);
180
sun4v_hvapi_init(void)181 void __init sun4v_hvapi_init(void)
182 {
183 unsigned long group, major, minor;
184
185 group = HV_GRP_SUN4V;
186 major = 1;
187 minor = 0;
188 if (sun4v_hvapi_register(group, major, &minor))
189 goto bad;
190
191 group = HV_GRP_CORE;
192 major = 1;
193 minor = 6;
194 if (sun4v_hvapi_register(group, major, &minor))
195 goto bad;
196
197 return;
198
199 bad:
200 prom_printf("HVAPI: Cannot register API group "
201 "%lx with major(%lu) minor(%lu)\n",
202 group, major, minor);
203 prom_halt();
204 }
205