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 */
17struct 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
26static 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
54static DEFINE_SPINLOCK(hvapi_lock);
55
56static 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
67static void __get_ref(struct api_info *p)
68{
69	p->refcnt++;
70}
71
72static 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 */
93int 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}
142EXPORT_SYMBOL(sun4v_hvapi_register);
143
144void 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}
155EXPORT_SYMBOL(sun4v_hvapi_unregister);
156
157int 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}
177EXPORT_SYMBOL(sun4v_hvapi_get);
178
179void __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
197bad:
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