From b8c5cec23d5c33b767a1cddebd4f8813a9563e3c Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Fri, 16 Feb 2007 17:33:36 +0100 Subject: [PATCH] Driver core: udev triggered device-<>driver binding We get two per-bus sysfs files: ls-l /sys/subsystem/usb drwxr-xr-x 2 root root 0 2007-02-16 16:42 devices drwxr-xr-x 7 root root 0 2007-02-16 14:55 drivers -rw-r--r-- 1 root root 4096 2007-02-16 16:42 drivers_autoprobe --w------- 1 root root 4096 2007-02-16 16:42 drivers_probe The flag "drivers_autoprobe" controls the behavior of the bus to bind devices by default, or just initialize the device and leave it alone. The command "drivers_probe" accepts a bus_id and the bus tries to bind a driver to this device. Systems who want to control the driver binding with udev, switch off the bus initiated probing: echo 0 > /sys/subsystem/usb/drivers_autoprobe echo 0 > /sys/subsystem/pcmcia/drivers_autoprobe ... and initiate the probing with udev rules like: ACTION=="add", SUBSYSTEM=="usb", ATTR{subsystem/drivers_probe}="$kernel" ACTION=="add", SUBSYSTEM=="pcmcia", ATTR{subsystem/drivers_probe}="$kernel" ... Custom driver binding can happen in earlier rules by something like: ACTION=="add", SUBSYSTEM=="usb", \ ATTRS{idVendor}=="1234", ATTRS{idProduct}=="5678" \ ATTR{subsystem/drivers//bind}="$kernel" This is intended to solve the modprobe.conf mess with "install-rules", custom bind/unbind-scripts and all the weird things people invented over the years. It should also provide the functionality "libusual" was supposed to do. With udev, one can just write a udev rule to drive all USB-disks at the third port of USB-hub by the "ub" driver, and everything else by usb-storage. One can also instruct udev to bind different wireless drivers to identical cards - just selected by the pcmcia slot-number, and whatever ... To use the mentioned rules, it needs udev version 106, to be able to write ATTR{}="$kernel" to sysfs files. Signed-off-by: Greg Kroah-Hartman --- drivers/base/bus.c | 84 +++++++++++++++++++++++++++++++++++++++--- include/linux/device.h | 34 +++++++++-------- 2 files changed, 97 insertions(+), 21 deletions(-) diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 253868e03c..9df2e6dff5 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -27,6 +27,9 @@ #define to_driver(obj) container_of(obj, struct device_driver, kobj) +static int __must_check bus_rescan_devices_helper(struct device *dev, + void *data); + static ssize_t drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf) { @@ -133,7 +136,6 @@ static decl_subsys(bus, &ktype_bus, NULL); #ifdef CONFIG_HOTPLUG - /* Manually detach a device from its associated driver. */ static int driver_helper(struct device *dev, void *data) { @@ -199,6 +201,33 @@ static ssize_t driver_bind(struct device_driver *drv, } static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind); +static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf) +{ + return sprintf(buf, "%d\n", bus->drivers_autoprobe); +} + +static ssize_t store_drivers_autoprobe(struct bus_type *bus, + const char *buf, size_t count) +{ + if (buf[0] == '0') + bus->drivers_autoprobe = 0; + else + bus->drivers_autoprobe = 1; + return count; +} + +static ssize_t store_drivers_probe(struct bus_type *bus, + const char *buf, size_t count) +{ + struct device *dev; + + dev = bus_find_device(bus, NULL, (void *)buf, driver_helper); + if (!dev) + return -ENODEV; + if (bus_rescan_devices_helper(dev, NULL) != 0) + return -EINVAL; + return count; +} #endif static struct device * next_device(struct klist_iter * i) @@ -425,7 +454,8 @@ int bus_attach_device(struct device * dev) if (bus) { dev->is_registered = 1; - ret = device_attach(dev); + if (bus->drivers_autoprobe) + ret = device_attach(dev); if (ret >= 0) { klist_add_tail(&dev->knode_bus, &bus->klist_devices); ret = 0; @@ -515,9 +545,41 @@ static void remove_bind_files(struct device_driver *drv) driver_remove_file(drv, &driver_attr_bind); driver_remove_file(drv, &driver_attr_unbind); } + +static int add_probe_files(struct bus_type *bus) +{ + int retval; + + bus->drivers_probe_attr.attr.name = "drivers_probe"; + bus->drivers_probe_attr.attr.mode = S_IWUSR; + bus->drivers_probe_attr.attr.owner = bus->owner; + bus->drivers_probe_attr.store = store_drivers_probe; + retval = bus_create_file(bus, &bus->drivers_probe_attr); + if (retval) + goto out; + + bus->drivers_autoprobe_attr.attr.name = "drivers_autoprobe"; + bus->drivers_autoprobe_attr.attr.mode = S_IWUSR | S_IRUGO; + bus->drivers_autoprobe_attr.attr.owner = bus->owner; + bus->drivers_autoprobe_attr.show = show_drivers_autoprobe; + bus->drivers_autoprobe_attr.store = store_drivers_autoprobe; + retval = bus_create_file(bus, &bus->drivers_autoprobe_attr); + if (retval) + bus_remove_file(bus, &bus->drivers_probe_attr); +out: + return retval; +} + +static void remove_probe_files(struct bus_type *bus) +{ + bus_remove_file(bus, &bus->drivers_autoprobe_attr); + bus_remove_file(bus, &bus->drivers_probe_attr); +} #else static inline int add_bind_files(struct device_driver *drv) { return 0; } static inline void remove_bind_files(struct device_driver *drv) {} +static inline int add_probe_files(struct bus_type *bus) { return 0; } +static inline void remove_probe_files(struct bus_type *bus) {} #endif /** @@ -541,9 +603,11 @@ int bus_add_driver(struct device_driver *drv) if ((error = kobject_register(&drv->kobj))) goto out_put_bus; - error = driver_attach(drv); - if (error) - goto out_unregister; + if (drv->bus->drivers_autoprobe) { + error = driver_attach(drv); + if (error) + goto out_unregister; + } klist_add_tail(&drv->knode_bus, &bus->klist_drivers); module_add_driver(drv->owner, drv); @@ -762,6 +826,12 @@ int bus_register(struct bus_type * bus) klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put); klist_init(&bus->klist_drivers, NULL, NULL); + + bus->drivers_autoprobe = 1; + retval = add_probe_files(bus); + if (retval) + goto bus_probe_files_fail; + retval = bus_add_attrs(bus); if (retval) goto bus_attrs_fail; @@ -770,6 +840,8 @@ int bus_register(struct bus_type * bus) return 0; bus_attrs_fail: + remove_probe_files(bus); +bus_probe_files_fail: kset_unregister(&bus->drivers); bus_drivers_fail: kset_unregister(&bus->devices); @@ -779,7 +851,6 @@ out: return retval; } - /** * bus_unregister - remove a bus from the system * @bus: bus. @@ -791,6 +862,7 @@ void bus_unregister(struct bus_type * bus) { pr_debug("bus %s: unregistering\n", bus->name); bus_remove_attrs(bus); + remove_probe_files(bus); kset_unregister(&bus->drivers); kset_unregister(&bus->devices); subsystem_unregister(&bus->subsys); diff --git a/include/linux/device.h b/include/linux/device.h index de0e73eae6..9d54fe13eb 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -34,9 +34,24 @@ struct device; struct device_driver; struct class; struct class_device; +struct bus_type; + +struct bus_attribute { + struct attribute attr; + ssize_t (*show)(struct bus_type *, char * buf); + ssize_t (*store)(struct bus_type *, const char * buf, size_t count); +}; + +#define BUS_ATTR(_name,_mode,_show,_store) \ +struct bus_attribute bus_attr_##_name = __ATTR(_name,_mode,_show,_store) + +extern int __must_check bus_create_file(struct bus_type *, + struct bus_attribute *); +extern void bus_remove_file(struct bus_type *, struct bus_attribute *); struct bus_type { const char * name; + struct module * owner; struct subsystem subsys; struct kset drivers; @@ -49,6 +64,8 @@ struct bus_type { struct bus_attribute * bus_attrs; struct device_attribute * dev_attrs; struct driver_attribute * drv_attrs; + struct bus_attribute drivers_autoprobe_attr; + struct bus_attribute drivers_probe_attr; int (*match)(struct device * dev, struct device_driver * drv); int (*uevent)(struct device *dev, char **envp, @@ -61,6 +78,8 @@ struct bus_type { int (*suspend_late)(struct device * dev, pm_message_t state); int (*resume_early)(struct device * dev); int (*resume)(struct device * dev); + + unsigned int drivers_autoprobe:1; }; extern int __must_check bus_register(struct bus_type * bus); @@ -102,21 +121,6 @@ extern int bus_unregister_notifier(struct bus_type *bus, #define BUS_NOTIFY_UNBIND_DRIVER 0x00000004 /* driver about to be unbound */ -/* sysfs interface for exporting bus attributes */ - -struct bus_attribute { - struct attribute attr; - ssize_t (*show)(struct bus_type *, char * buf); - ssize_t (*store)(struct bus_type *, const char * buf, size_t count); -}; - -#define BUS_ATTR(_name,_mode,_show,_store) \ -struct bus_attribute bus_attr_##_name = __ATTR(_name,_mode,_show,_store) - -extern int __must_check bus_create_file(struct bus_type *, - struct bus_attribute *); -extern void bus_remove_file(struct bus_type *, struct bus_attribute *); - struct device_driver { const char * name; struct bus_type * bus; -- 2.39.5