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