xref: /openbmc/linux/arch/sparc/kernel/hvapi.c (revision a36954f5)
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_ATU,		.flags = FLAG_PRE_API	},
43 	{ .group = HV_GRP_NIAG_PERF,	.flags = FLAG_PRE_API	},
44 	{ .group = HV_GRP_FIRE_PERF,				},
45 	{ .group = HV_GRP_N2_CPU,				},
46 	{ .group = HV_GRP_NIU,					},
47 	{ .group = HV_GRP_VF_CPU,				},
48 	{ .group = HV_GRP_KT_CPU,				},
49 	{ .group = HV_GRP_VT_CPU,				},
50 	{ .group = HV_GRP_T5_CPU,				},
51 	{ .group = HV_GRP_DIAG,		.flags = FLAG_PRE_API	},
52 	{ .group = HV_GRP_M7_PERF,				},
53 };
54 
55 static DEFINE_SPINLOCK(hvapi_lock);
56 
57 static struct api_info *__get_info(unsigned long group)
58 {
59 	int i;
60 
61 	for (i = 0; i < ARRAY_SIZE(api_table); i++) {
62 		if (api_table[i].group == group)
63 			return &api_table[i];
64 	}
65 	return NULL;
66 }
67 
68 static void __get_ref(struct api_info *p)
69 {
70 	p->refcnt++;
71 }
72 
73 static void __put_ref(struct api_info *p)
74 {
75 	if (--p->refcnt == 0) {
76 		unsigned long ignore;
77 
78 		sun4v_set_version(p->group, 0, 0, &ignore);
79 		p->major = p->minor = 0;
80 	}
81 }
82 
83 /* Register a hypervisor API specification.  It indicates the
84  * API group and desired major+minor.
85  *
86  * If an existing API registration exists '0' (success) will
87  * be returned if it is compatible with the one being registered.
88  * Otherwise a negative error code will be returned.
89  *
90  * Otherwise an attempt will be made to negotiate the requested
91  * API group/major/minor with the hypervisor, and errors returned
92  * if that does not succeed.
93  */
94 int sun4v_hvapi_register(unsigned long group, unsigned long major,
95 			 unsigned long *minor)
96 {
97 	struct api_info *p;
98 	unsigned long flags;
99 	int ret;
100 
101 	spin_lock_irqsave(&hvapi_lock, flags);
102 	p = __get_info(group);
103 	ret = -EINVAL;
104 	if (p) {
105 		if (p->refcnt) {
106 			ret = -EINVAL;
107 			if (p->major == major) {
108 				*minor = p->minor;
109 				ret = 0;
110 			}
111 		} else {
112 			unsigned long actual_minor;
113 			unsigned long hv_ret;
114 
115 			hv_ret = sun4v_set_version(group, major, *minor,
116 						   &actual_minor);
117 			ret = -EINVAL;
118 			if (hv_ret == HV_EOK) {
119 				*minor = actual_minor;
120 				p->major = major;
121 				p->minor = actual_minor;
122 				ret = 0;
123 			} else if (hv_ret == HV_EBADTRAP ||
124 				   hv_ret == HV_ENOTSUPPORTED) {
125 				if (p->flags & FLAG_PRE_API) {
126 					if (major == 1) {
127 						p->major = 1;
128 						p->minor = 0;
129 						*minor = 0;
130 						ret = 0;
131 					}
132 				}
133 			}
134 		}
135 
136 		if (ret == 0)
137 			__get_ref(p);
138 	}
139 	spin_unlock_irqrestore(&hvapi_lock, flags);
140 
141 	return ret;
142 }
143 EXPORT_SYMBOL(sun4v_hvapi_register);
144 
145 void sun4v_hvapi_unregister(unsigned long group)
146 {
147 	struct api_info *p;
148 	unsigned long flags;
149 
150 	spin_lock_irqsave(&hvapi_lock, flags);
151 	p = __get_info(group);
152 	if (p)
153 		__put_ref(p);
154 	spin_unlock_irqrestore(&hvapi_lock, flags);
155 }
156 EXPORT_SYMBOL(sun4v_hvapi_unregister);
157 
158 int sun4v_hvapi_get(unsigned long group,
159 		    unsigned long *major,
160 		    unsigned long *minor)
161 {
162 	struct api_info *p;
163 	unsigned long flags;
164 	int ret;
165 
166 	spin_lock_irqsave(&hvapi_lock, flags);
167 	ret = -EINVAL;
168 	p = __get_info(group);
169 	if (p && p->refcnt) {
170 		*major = p->major;
171 		*minor = p->minor;
172 		ret = 0;
173 	}
174 	spin_unlock_irqrestore(&hvapi_lock, flags);
175 
176 	return ret;
177 }
178 EXPORT_SYMBOL(sun4v_hvapi_get);
179 
180 void __init sun4v_hvapi_init(void)
181 {
182 	unsigned long group, major, minor;
183 
184 	group = HV_GRP_SUN4V;
185 	major = 1;
186 	minor = 0;
187 	if (sun4v_hvapi_register(group, major, &minor))
188 		goto bad;
189 
190 	group = HV_GRP_CORE;
191 	major = 1;
192 	minor = 1;
193 	if (sun4v_hvapi_register(group, major, &minor))
194 		goto bad;
195 
196 	return;
197 
198 bad:
199 	prom_printf("HVAPI: Cannot register API group "
200 		    "%lx with major(%lu) minor(%lu)\n",
201 		    group, major, minor);
202 	prom_halt();
203 }
204