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 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 65 static void __get_ref(struct api_info *p) 66 { 67 p->refcnt++; 68 } 69 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 */ 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); 141 142 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); 154 155 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); 176 177 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