From 116af378201ef793424cd10508ccf18b06d8a021 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 25 Oct 2006 13:44:59 +1000 Subject: Driver core: add notification of bus events I finally did as you suggested and added the notifier to the struct bus_type itself. There are still problems to be expected is something attaches to a bus type where the code can hook in different struct device sub-classes (which is imho a big bogosity but I won't even try to argue that case now) but it will solve nicely a number of issues I've had so far. That also means that clients interested in registering for such notifications have to do it before devices are added and after bus types are registered. Fortunately, most bus types that matter for the various usage scenarios I have in mind are registerd at postcore_initcall time, which means I have a really nice spot at arch_initcall time to add my notifiers. There are 4 notifications provided. Device being added (before hooked to the bus) and removed (failure of previous case or after being unhooked from the bus), along with driver being bound to a device and about to be unbound. The usage I have for these are: - The 2 first ones are used to maintain a struct device_ext that is hooked to struct device.firmware_data. This structure contains for now a pointer to the Open Firmware node related to the device (if any), the NUMA node ID (for quick access to it) and the DMA operations pointers & iommu table instance for DMA to/from this device. For bus types I own (like IBM VIO or EBUS), I just maintain that structure directly from the bus code when creating the devices. But for bus types managed by generic code like PCI or platform (actually, of_platform which is a variation of platform linked to Open Firmware device-tree), I need this notifier. - The other two ones have a completely different usage scenario. I have cases where multiple devices and their drivers depend on each other. For example, the IBM EMAC network driver needs to attach to a MAL DMA engine which is a separate device, and a PHY interface which is also a separate device. They are all of_platform_device's (well, about to be with my upcoming patches) but there is no say in what precise order the core will "probe" them and instanciate the various modules. The solution I found for that is to have the drivers for emac to use multithread_probe, and wait for a driver to be bound to the target MAL and PHY control devices (the device-tree contains reference to the MAL and PHY interface nodes, which I can then match to of_platform_devices). Right now, I've been polling, but with that notifier, I can more cleanly wait (with a timeout of course). Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers/base/dd.c') diff --git a/drivers/base/dd.c b/drivers/base/dd.c index c5d6bb4290a..9c88b1e34bc 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -52,6 +52,11 @@ int device_bind_driver(struct device *dev) pr_debug("bound device '%s' to driver '%s'\n", dev->bus_id, dev->driver->name); + + if (dev->bus) + blocking_notifier_call_chain(&dev->bus->bus_notifier, + BUS_NOTIFY_BOUND_DRIVER, dev); + klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices); ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj, kobject_name(&dev->kobj)); @@ -288,6 +293,11 @@ static void __device_release_driver(struct device * dev) sysfs_remove_link(&dev->kobj, "driver"); klist_remove(&dev->knode_driver); + if (dev->bus) + blocking_notifier_call_chain(&dev->bus->bus_notifier, + BUS_NOTIFY_UNBIND_DRIVER, + dev); + if (dev->bus && dev->bus->remove) dev->bus->remove(dev); else if (drv->remove) -- cgit v1.2.3 From 1901fb2604fbcd53201f38725182ea807581159e Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Sat, 7 Oct 2006 21:55:55 +0200 Subject: Driver core: fix "driver" symlink timing Create the "driver" link before the child device may be created by the probing logic. This makes it possible for userspace (udev), to determine the driver property of the parent device, at the time the child device is created. Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 82 +++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 52 insertions(+), 30 deletions(-) (limited to 'drivers/base/dd.c') diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 9c88b1e34bc..510e7884975 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -26,28 +26,12 @@ #define to_drv(node) container_of(node, struct device_driver, kobj.entry) -/** - * device_bind_driver - bind a driver to one device. - * @dev: device. - * - * Allow manual attachment of a driver to a device. - * Caller must have already set @dev->driver. - * - * Note that this does not modify the bus reference count - * nor take the bus's rwsem. Please verify those are accounted - * for before calling this. (It is ok to call with no other effort - * from a driver's probe() method.) - * - * This function must be called with @dev->sem held. - */ -int device_bind_driver(struct device *dev) +static void driver_bound(struct device *dev) { - int ret; - if (klist_node_attached(&dev->knode_driver)) { printk(KERN_WARNING "%s: device %s already bound\n", __FUNCTION__, kobject_name(&dev->kobj)); - return 0; + return; } pr_debug("bound device '%s' to driver '%s'\n", @@ -58,6 +42,12 @@ int device_bind_driver(struct device *dev) BUS_NOTIFY_BOUND_DRIVER, dev); klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices); +} + +static int driver_sysfs_add(struct device *dev) +{ + int ret; + ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj, kobject_name(&dev->kobj)); if (ret == 0) { @@ -70,6 +60,36 @@ int device_bind_driver(struct device *dev) return ret; } +static void driver_sysfs_remove(struct device *dev) +{ + struct device_driver *drv = dev->driver; + + if (drv) { + sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); + sysfs_remove_link(&dev->kobj, "driver"); + } +} + +/** + * device_bind_driver - bind a driver to one device. + * @dev: device. + * + * Allow manual attachment of a driver to a device. + * Caller must have already set @dev->driver. + * + * Note that this does not modify the bus reference count + * nor take the bus's rwsem. Please verify those are accounted + * for before calling this. (It is ok to call with no other effort + * from a driver's probe() method.) + * + * This function must be called with @dev->sem held. + */ +int device_bind_driver(struct device *dev) +{ + driver_bound(dev); + return driver_sysfs_add(dev); +} + struct stupid_thread_structure { struct device_driver *drv; struct device *dev; @@ -90,30 +110,32 @@ static int really_probe(void *void_data) drv->bus->name, drv->name, dev->bus_id); dev->driver = drv; + if (driver_sysfs_add(dev)) { + printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", + __FUNCTION__, dev->bus_id); + goto probe_failed; + } + if (dev->bus->probe) { ret = dev->bus->probe(dev); - if (ret) { - dev->driver = NULL; + if (ret) goto probe_failed; - } } else if (drv->probe) { ret = drv->probe(dev); - if (ret) { - dev->driver = NULL; + if (ret) goto probe_failed; - } - } - if (device_bind_driver(dev)) { - printk(KERN_ERR "%s: device_bind_driver(%s) failed\n", - __FUNCTION__, dev->bus_id); - /* How does undo a ->probe? We're screwed. */ } + + driver_bound(dev); ret = 1; pr_debug("%s: Bound Device %s to Driver %s\n", drv->bus->name, dev->bus_id, drv->name); goto done; probe_failed: + driver_sysfs_remove(dev); + dev->driver = NULL; + if (ret == -ENODEV || ret == -ENXIO) { /* Driver matched, but didn't support device * or device not found. @@ -289,7 +311,7 @@ static void __device_release_driver(struct device * dev) drv = dev->driver; if (drv) { get_driver(drv); - sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); + driver_sysfs_remove(dev); sysfs_remove_link(&dev->kobj, "driver"); klist_remove(&dev->knode_driver); -- cgit v1.2.3