Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 1 | #define DPRINTK(fmt, args...) \ |
| 2 | pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \ |
| 3 | __func__, __LINE__, ##args) |
| 4 | |
| 5 | #include <linux/kernel.h> |
| 6 | #include <linux/err.h> |
| 7 | #include <linux/string.h> |
| 8 | #include <linux/ctype.h> |
| 9 | #include <linux/fcntl.h> |
| 10 | #include <linux/mm.h> |
| 11 | #include <linux/proc_fs.h> |
| 12 | #include <linux/notifier.h> |
| 13 | #include <linux/kthread.h> |
| 14 | #include <linux/mutex.h> |
| 15 | #include <linux/io.h> |
| 16 | |
| 17 | #include <asm/page.h> |
| 18 | #include <asm/pgtable.h> |
| 19 | #include <asm/xen/hypervisor.h> |
| 20 | #include <xen/xenbus.h> |
| 21 | #include <xen/events.h> |
| 22 | #include <xen/page.h> |
| 23 | |
| 24 | #include <xen/platform_pci.h> |
| 25 | |
| 26 | #include "xenbus_comms.h" |
| 27 | #include "xenbus_probe.h" |
| 28 | |
| 29 | |
| 30 | /* device/<type>/<id> => <type>-<id> */ |
| 31 | static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename) |
| 32 | { |
| 33 | nodename = strchr(nodename, '/'); |
| 34 | if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) { |
| 35 | printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename); |
| 36 | return -EINVAL; |
| 37 | } |
| 38 | |
| 39 | strlcpy(bus_id, nodename + 1, XEN_BUS_ID_SIZE); |
| 40 | if (!strchr(bus_id, '/')) { |
| 41 | printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id); |
| 42 | return -EINVAL; |
| 43 | } |
| 44 | *strchr(bus_id, '/') = '-'; |
| 45 | return 0; |
| 46 | } |
| 47 | |
| 48 | /* device/<typename>/<name> */ |
Ian Campbell | 6bac7f9 | 2010-12-10 14:39:15 +0000 | [diff] [blame] | 49 | static int xenbus_probe_frontend(struct xen_bus_type *bus, const char *type, |
| 50 | const char *name) |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 51 | { |
| 52 | char *nodename; |
| 53 | int err; |
| 54 | |
| 55 | nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", bus->root, type, name); |
| 56 | if (!nodename) |
| 57 | return -ENOMEM; |
| 58 | |
| 59 | DPRINTK("%s", nodename); |
| 60 | |
| 61 | err = xenbus_probe_node(bus, type, nodename); |
| 62 | kfree(nodename); |
| 63 | return err; |
| 64 | } |
| 65 | |
Ian Campbell | 6bac7f9 | 2010-12-10 14:39:15 +0000 | [diff] [blame] | 66 | static int xenbus_uevent_frontend(struct device *_dev, |
| 67 | struct kobj_uevent_env *env) |
Ian Campbell | df66025 | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 68 | { |
| 69 | struct xenbus_device *dev = to_xenbus_device(_dev); |
| 70 | |
| 71 | if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype)) |
| 72 | return -ENOMEM; |
| 73 | |
| 74 | return 0; |
| 75 | } |
| 76 | |
| 77 | |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 78 | static void backend_changed(struct xenbus_watch *watch, |
| 79 | const char **vec, unsigned int len) |
| 80 | { |
| 81 | xenbus_otherend_changed(watch, vec, len, 1); |
| 82 | } |
| 83 | |
| 84 | static struct device_attribute xenbus_frontend_dev_attrs[] = { |
| 85 | __ATTR_NULL |
| 86 | }; |
| 87 | |
| 88 | static struct xen_bus_type xenbus_frontend = { |
| 89 | .root = "device", |
Ian Campbell | 6bac7f9 | 2010-12-10 14:39:15 +0000 | [diff] [blame] | 90 | .levels = 2, /* device/type/<id> */ |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 91 | .get_bus_id = frontend_bus_id, |
| 92 | .probe = xenbus_probe_frontend, |
| 93 | .otherend_changed = backend_changed, |
| 94 | .bus = { |
Ian Campbell | 6bac7f9 | 2010-12-10 14:39:15 +0000 | [diff] [blame] | 95 | .name = "xen", |
| 96 | .match = xenbus_match, |
| 97 | .uevent = xenbus_uevent_frontend, |
| 98 | .probe = xenbus_dev_probe, |
| 99 | .remove = xenbus_dev_remove, |
| 100 | .shutdown = xenbus_dev_shutdown, |
| 101 | .dev_attrs = xenbus_frontend_dev_attrs, |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 102 | |
Ian Campbell | 6bac7f9 | 2010-12-10 14:39:15 +0000 | [diff] [blame] | 103 | .suspend = xenbus_dev_suspend, |
| 104 | .resume = xenbus_dev_resume, |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 105 | }, |
| 106 | }; |
| 107 | |
| 108 | static void frontend_changed(struct xenbus_watch *watch, |
| 109 | const char **vec, unsigned int len) |
| 110 | { |
| 111 | DPRINTK(""); |
| 112 | |
| 113 | xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend); |
| 114 | } |
| 115 | |
| 116 | |
| 117 | /* We watch for devices appearing and vanishing. */ |
| 118 | static struct xenbus_watch fe_watch = { |
| 119 | .node = "device", |
| 120 | .callback = frontend_changed, |
| 121 | }; |
| 122 | |
| 123 | static int read_backend_details(struct xenbus_device *xendev) |
| 124 | { |
| 125 | return xenbus_read_otherend_details(xendev, "backend-id", "backend"); |
| 126 | } |
| 127 | |
| 128 | static int is_device_connecting(struct device *dev, void *data) |
| 129 | { |
| 130 | struct xenbus_device *xendev = to_xenbus_device(dev); |
| 131 | struct device_driver *drv = data; |
| 132 | struct xenbus_driver *xendrv; |
| 133 | |
| 134 | /* |
| 135 | * A device with no driver will never connect. We care only about |
| 136 | * devices which should currently be in the process of connecting. |
| 137 | */ |
| 138 | if (!dev->driver) |
| 139 | return 0; |
| 140 | |
| 141 | /* Is this search limited to a particular driver? */ |
| 142 | if (drv && (dev->driver != drv)) |
| 143 | return 0; |
| 144 | |
| 145 | xendrv = to_xenbus_driver(dev->driver); |
| 146 | return (xendev->state < XenbusStateConnected || |
| 147 | (xendev->state == XenbusStateConnected && |
| 148 | xendrv->is_ready && !xendrv->is_ready(xendev))); |
| 149 | } |
| 150 | |
| 151 | static int exists_connecting_device(struct device_driver *drv) |
| 152 | { |
| 153 | return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, |
| 154 | is_device_connecting); |
| 155 | } |
| 156 | |
| 157 | static int print_device_status(struct device *dev, void *data) |
| 158 | { |
| 159 | struct xenbus_device *xendev = to_xenbus_device(dev); |
| 160 | struct device_driver *drv = data; |
| 161 | |
| 162 | /* Is this operation limited to a particular driver? */ |
| 163 | if (drv && (dev->driver != drv)) |
| 164 | return 0; |
| 165 | |
| 166 | if (!dev->driver) { |
| 167 | /* Information only: is this too noisy? */ |
| 168 | printk(KERN_INFO "XENBUS: Device with no driver: %s\n", |
| 169 | xendev->nodename); |
| 170 | } else if (xendev->state < XenbusStateConnected) { |
| 171 | enum xenbus_state rstate = XenbusStateUnknown; |
| 172 | if (xendev->otherend) |
| 173 | rstate = xenbus_read_driver_state(xendev->otherend); |
| 174 | printk(KERN_WARNING "XENBUS: Timeout connecting " |
| 175 | "to device: %s (local state %d, remote state %d)\n", |
| 176 | xendev->nodename, xendev->state, rstate); |
| 177 | } |
| 178 | |
| 179 | return 0; |
| 180 | } |
| 181 | |
| 182 | /* We only wait for device setup after most initcalls have run. */ |
| 183 | static int ready_to_wait_for_devices; |
| 184 | |
| 185 | /* |
| 186 | * On a 5-minute timeout, wait for all devices currently configured. We need |
| 187 | * to do this to guarantee that the filesystems and / or network devices |
| 188 | * needed for boot are available, before we can allow the boot to proceed. |
| 189 | * |
| 190 | * This needs to be on a late_initcall, to happen after the frontend device |
| 191 | * drivers have been initialised, but before the root fs is mounted. |
| 192 | * |
| 193 | * A possible improvement here would be to have the tools add a per-device |
| 194 | * flag to the store entry, indicating whether it is needed at boot time. |
| 195 | * This would allow people who knew what they were doing to accelerate their |
| 196 | * boot slightly, but of course needs tools or manual intervention to set up |
| 197 | * those flags correctly. |
| 198 | */ |
| 199 | static void wait_for_devices(struct xenbus_driver *xendrv) |
| 200 | { |
| 201 | unsigned long start = jiffies; |
| 202 | struct device_driver *drv = xendrv ? &xendrv->driver : NULL; |
| 203 | unsigned int seconds_waited = 0; |
| 204 | |
| 205 | if (!ready_to_wait_for_devices || !xen_domain()) |
| 206 | return; |
| 207 | |
| 208 | while (exists_connecting_device(drv)) { |
| 209 | if (time_after(jiffies, start + (seconds_waited+5)*HZ)) { |
| 210 | if (!seconds_waited) |
| 211 | printk(KERN_WARNING "XENBUS: Waiting for " |
| 212 | "devices to initialise: "); |
| 213 | seconds_waited += 5; |
| 214 | printk("%us...", 300 - seconds_waited); |
| 215 | if (seconds_waited == 300) |
| 216 | break; |
| 217 | } |
| 218 | |
| 219 | schedule_timeout_interruptible(HZ/10); |
| 220 | } |
| 221 | |
| 222 | if (seconds_waited) |
| 223 | printk("\n"); |
| 224 | |
| 225 | bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, |
| 226 | print_device_status); |
| 227 | } |
| 228 | |
| 229 | int __xenbus_register_frontend(struct xenbus_driver *drv, |
| 230 | struct module *owner, const char *mod_name) |
| 231 | { |
| 232 | int ret; |
| 233 | |
| 234 | drv->read_otherend_details = read_backend_details; |
| 235 | |
| 236 | ret = xenbus_register_driver_common(drv, &xenbus_frontend, |
| 237 | owner, mod_name); |
| 238 | if (ret) |
| 239 | return ret; |
| 240 | |
| 241 | /* If this driver is loaded as a module wait for devices to attach. */ |
| 242 | wait_for_devices(drv); |
| 243 | |
| 244 | return 0; |
| 245 | } |
| 246 | EXPORT_SYMBOL_GPL(__xenbus_register_frontend); |
| 247 | |
Ian Campbell | df66025 | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 248 | static int frontend_probe_and_watch(struct notifier_block *notifier, |
| 249 | unsigned long event, |
| 250 | void *data) |
| 251 | { |
| 252 | /* Enumerate devices in xenstore and watch for changes. */ |
| 253 | xenbus_probe_devices(&xenbus_frontend); |
Ian Campbell | df66025 | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 254 | register_xenbus_watch(&fe_watch); |
Jeremy Fitzhardinge | 0ff4fdf | 2010-03-29 14:38:54 -0700 | [diff] [blame] | 255 | |
Ian Campbell | df66025 | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 256 | return NOTIFY_DONE; |
| 257 | } |
| 258 | |
| 259 | |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 260 | static int __init xenbus_probe_frontend_init(void) |
| 261 | { |
Ian Campbell | df66025 | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 262 | static struct notifier_block xenstore_notifier = { |
| 263 | .notifier_call = frontend_probe_and_watch |
| 264 | }; |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 265 | int err; |
| 266 | |
| 267 | DPRINTK(""); |
| 268 | |
| 269 | /* Register ourselves with the kernel bus subsystem */ |
| 270 | err = bus_register(&xenbus_frontend.bus); |
Jeremy Fitzhardinge | 0ff4fdf | 2010-03-29 14:38:54 -0700 | [diff] [blame] | 271 | if (err) |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 272 | return err; |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 273 | |
Ian Campbell | df66025 | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 274 | register_xenstore_notifier(&xenstore_notifier); |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 275 | |
| 276 | return 0; |
| 277 | } |
Jeremy Fitzhardinge | 806f546 | 2009-03-04 22:31:45 -0800 | [diff] [blame] | 278 | subsys_initcall(xenbus_probe_frontend_init); |
Ian Campbell | 2de06cc | 2009-02-09 12:05:51 -0800 | [diff] [blame] | 279 | |
| 280 | #ifndef MODULE |
| 281 | static int __init boot_wait_for_devices(void) |
| 282 | { |
| 283 | if (xen_hvm_domain() && !xen_platform_pci_unplug) |
| 284 | return -ENODEV; |
| 285 | |
| 286 | ready_to_wait_for_devices = 1; |
| 287 | wait_for_devices(NULL); |
| 288 | return 0; |
| 289 | } |
| 290 | |
| 291 | late_initcall(boot_wait_for_devices); |
| 292 | #endif |
Jeremy Fitzhardinge | 1b31a14 | 2009-03-27 16:29:44 -0700 | [diff] [blame] | 293 | |
| 294 | MODULE_LICENSE("GPL"); |