1 /****************************************************************************** 2 * xenbus.h 3 * 4 * Talks to Xen Store to figure out what devices we have. 5 * 6 * Copyright (C) 2005 Rusty Russell, IBM Corporation 7 * Copyright (C) 2005 XenSource Ltd. 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License version 2 11 * as published by the Free Software Foundation; or, when distributed 12 * separately from the Linux kernel or incorporated into other 13 * software packages, subject to the following license: 14 * 15 * Permission is hereby granted, free of charge, to any person obtaining a copy 16 * of this source file (the "Software"), to deal in the Software without 17 * restriction, including without limitation the rights to use, copy, modify, 18 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 19 * and to permit persons to whom the Software is furnished to do so, subject to 20 * the following conditions: 21 * 22 * The above copyright notice and this permission notice shall be included in 23 * all copies or substantial portions of the Software. 24 * 25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 26 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 27 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 28 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 29 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 30 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 31 * IN THE SOFTWARE. 32 */ 33 34 #ifndef _XEN_XENBUS_H 35 #define _XEN_XENBUS_H 36 37 #include <linux/device.h> 38 #include <linux/notifier.h> 39 #include <linux/mutex.h> 40 #include <linux/export.h> 41 #include <linux/fs.h> 42 #include <linux/completion.h> 43 #include <linux/init.h> 44 #include <linux/slab.h> 45 #include <linux/semaphore.h> 46 #include <xen/interface/xen.h> 47 #include <xen/interface/grant_table.h> 48 #include <xen/interface/io/xenbus.h> 49 #include <xen/interface/io/xs_wire.h> 50 #include <xen/interface/event_channel.h> 51 52 #define XENBUS_MAX_RING_GRANT_ORDER 4 53 #define XENBUS_MAX_RING_GRANTS (1U << XENBUS_MAX_RING_GRANT_ORDER) 54 55 /* Register callback to watch this node. */ 56 struct xenbus_watch 57 { 58 struct list_head list; 59 60 /* Path being watched. */ 61 const char *node; 62 63 unsigned int nr_pending; 64 65 /* 66 * Called just before enqueing new event while a spinlock is held. 67 * The event will be discarded if this callback returns false. 68 */ 69 bool (*will_handle)(struct xenbus_watch *, 70 const char *path, const char *token); 71 72 /* Callback (executed in a process context with no locks held). */ 73 void (*callback)(struct xenbus_watch *, 74 const char *path, const char *token); 75 }; 76 77 78 /* A xenbus device. */ 79 struct xenbus_device { 80 const char *devicetype; 81 const char *nodename; 82 const char *otherend; 83 int otherend_id; 84 struct xenbus_watch otherend_watch; 85 struct device dev; 86 enum xenbus_state state; 87 struct completion down; 88 struct work_struct work; 89 struct semaphore reclaim_sem; 90 91 /* Event channel based statistics and settings. */ 92 atomic_t event_channels; 93 atomic_t events; 94 atomic_t spurious_events; 95 atomic_t jiffies_eoi_delayed; 96 unsigned int spurious_threshold; 97 }; 98 99 static inline struct xenbus_device *to_xenbus_device(struct device *dev) 100 { 101 return container_of(dev, struct xenbus_device, dev); 102 } 103 104 struct xenbus_device_id 105 { 106 /* .../device/<device_type>/<identifier> */ 107 char devicetype[32]; /* General class of device. */ 108 }; 109 110 /* A xenbus driver. */ 111 struct xenbus_driver { 112 const char *name; /* defaults to ids[0].devicetype */ 113 const struct xenbus_device_id *ids; 114 bool allow_rebind; /* avoid setting xenstore closed during remove */ 115 int (*probe)(struct xenbus_device *dev, 116 const struct xenbus_device_id *id); 117 void (*otherend_changed)(struct xenbus_device *dev, 118 enum xenbus_state backend_state); 119 int (*remove)(struct xenbus_device *dev); 120 int (*suspend)(struct xenbus_device *dev); 121 int (*resume)(struct xenbus_device *dev); 122 int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *); 123 struct device_driver driver; 124 int (*read_otherend_details)(struct xenbus_device *dev); 125 int (*is_ready)(struct xenbus_device *dev); 126 void (*reclaim_memory)(struct xenbus_device *dev); 127 }; 128 129 static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv) 130 { 131 return container_of(drv, struct xenbus_driver, driver); 132 } 133 134 int __must_check __xenbus_register_frontend(struct xenbus_driver *drv, 135 struct module *owner, 136 const char *mod_name); 137 int __must_check __xenbus_register_backend(struct xenbus_driver *drv, 138 struct module *owner, 139 const char *mod_name); 140 141 #define xenbus_register_frontend(drv) \ 142 __xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME) 143 #define xenbus_register_backend(drv) \ 144 __xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME) 145 146 void xenbus_unregister_driver(struct xenbus_driver *drv); 147 148 struct xenbus_transaction 149 { 150 u32 id; 151 }; 152 153 /* Nil transaction ID. */ 154 #define XBT_NIL ((struct xenbus_transaction) { 0 }) 155 156 char **xenbus_directory(struct xenbus_transaction t, 157 const char *dir, const char *node, unsigned int *num); 158 void *xenbus_read(struct xenbus_transaction t, 159 const char *dir, const char *node, unsigned int *len); 160 int xenbus_write(struct xenbus_transaction t, 161 const char *dir, const char *node, const char *string); 162 int xenbus_mkdir(struct xenbus_transaction t, 163 const char *dir, const char *node); 164 int xenbus_exists(struct xenbus_transaction t, 165 const char *dir, const char *node); 166 int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node); 167 int xenbus_transaction_start(struct xenbus_transaction *t); 168 int xenbus_transaction_end(struct xenbus_transaction t, int abort); 169 170 /* Single read and scanf: returns -errno or num scanned if > 0. */ 171 __scanf(4, 5) 172 int xenbus_scanf(struct xenbus_transaction t, 173 const char *dir, const char *node, const char *fmt, ...); 174 175 /* Read an (optional) unsigned value. */ 176 unsigned int xenbus_read_unsigned(const char *dir, const char *node, 177 unsigned int default_val); 178 179 /* Single printf and write: returns -errno or 0. */ 180 __printf(4, 5) 181 int xenbus_printf(struct xenbus_transaction t, 182 const char *dir, const char *node, const char *fmt, ...); 183 184 /* Generic read function: NULL-terminated triples of name, 185 * sprintf-style type string, and pointer. Returns 0 or errno.*/ 186 int xenbus_gather(struct xenbus_transaction t, const char *dir, ...); 187 188 /* notifer routines for when the xenstore comes up */ 189 extern int xenstored_ready; 190 int register_xenstore_notifier(struct notifier_block *nb); 191 void unregister_xenstore_notifier(struct notifier_block *nb); 192 193 int register_xenbus_watch(struct xenbus_watch *watch); 194 void unregister_xenbus_watch(struct xenbus_watch *watch); 195 void xs_suspend(void); 196 void xs_resume(void); 197 void xs_suspend_cancel(void); 198 199 struct work_struct; 200 201 #define XENBUS_IS_ERR_READ(str) ({ \ 202 if (!IS_ERR(str) && strlen(str) == 0) { \ 203 kfree(str); \ 204 str = ERR_PTR(-ERANGE); \ 205 } \ 206 IS_ERR(str); \ 207 }) 208 209 #define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE) 210 211 int xenbus_watch_path(struct xenbus_device *dev, const char *path, 212 struct xenbus_watch *watch, 213 bool (*will_handle)(struct xenbus_watch *, 214 const char *, const char *), 215 void (*callback)(struct xenbus_watch *, 216 const char *, const char *)); 217 __printf(5, 6) 218 int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch, 219 bool (*will_handle)(struct xenbus_watch *, 220 const char *, const char *), 221 void (*callback)(struct xenbus_watch *, 222 const char *, const char *), 223 const char *pathfmt, ...); 224 225 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state); 226 int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr, 227 unsigned int nr_pages, grant_ref_t *grefs); 228 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs, 229 unsigned int nr_grefs, void **vaddr); 230 231 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr); 232 233 int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port); 234 int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port); 235 236 enum xenbus_state xenbus_read_driver_state(const char *path); 237 238 __printf(3, 4) 239 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...); 240 __printf(3, 4) 241 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...); 242 243 const char *xenbus_strstate(enum xenbus_state state); 244 int xenbus_dev_is_online(struct xenbus_device *dev); 245 int xenbus_frontend_closed(struct xenbus_device *dev); 246 247 extern const struct file_operations xen_xenbus_fops; 248 extern struct xenstore_domain_interface *xen_store_interface; 249 extern int xen_store_evtchn; 250 251 #endif /* _XEN_XENBUS_H */ 252