d1c3414c2a
Allow drivers to report at probe time that they cannot get all the resources
required by the device, and should be retried at a later time.
This should completely solve the problem of getting devices
initialized in the right order. Right now this is mostly handled by
mucking about with initcall ordering which is a complete hack, and
doesn't even remotely handle the case where device drivers are in
modules. This approach completely sidesteps the issues by allowing
driver registration to occur in any order, and any driver can request
to be retried after a few more other drivers get probed.
v4: - Integrate Manjunath's addition of a separate workqueue
- Change -EAGAIN to -EPROBE_DEFER for drivers to trigger deferral
- Update comment blocks to reflect how the code really works
v3: - Hold off workqueue scheduling until late_initcall so that the bulk
of driver probes are complete before we start retrying deferred devices.
- Tested with simple use cases. Still needs more testing though.
Using it to get rid of the gpio early_initcall madness, or to replace
the ASoC internal probe deferral code would be ideal.
v2: - added locking so it should no longer be utterly broken in that regard
- remove device from deferred list at device_del time.
- Still completely untested with any real use case, but has been
boot tested.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dilan Lee <dilee@nvidia.com>
Cc: Manjunath GKondaiah <manjunath.gkondaiah@linaro.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: David Daney <david.daney@cavium.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
135 lines
4.5 KiB
C
135 lines
4.5 KiB
C
#include <linux/notifier.h>
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/**
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* struct subsys_private - structure to hold the private to the driver core portions of the bus_type/class structure.
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*
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* @subsys - the struct kset that defines this subsystem
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* @devices_kset - the subsystem's 'devices' directory
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* @interfaces - list of subsystem interfaces associated
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* @mutex - protect the devices, and interfaces lists.
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*
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* @drivers_kset - the list of drivers associated
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* @klist_devices - the klist to iterate over the @devices_kset
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* @klist_drivers - the klist to iterate over the @drivers_kset
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* @bus_notifier - the bus notifier list for anything that cares about things
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* on this bus.
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* @bus - pointer back to the struct bus_type that this structure is associated
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* with.
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*
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* @glue_dirs - "glue" directory to put in-between the parent device to
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* avoid namespace conflicts
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* @class - pointer back to the struct class that this structure is associated
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* with.
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*
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* This structure is the one that is the actual kobject allowing struct
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* bus_type/class to be statically allocated safely. Nothing outside of the
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* driver core should ever touch these fields.
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*/
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struct subsys_private {
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struct kset subsys;
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struct kset *devices_kset;
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struct list_head interfaces;
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struct mutex mutex;
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struct kset *drivers_kset;
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struct klist klist_devices;
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struct klist klist_drivers;
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struct blocking_notifier_head bus_notifier;
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unsigned int drivers_autoprobe:1;
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struct bus_type *bus;
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struct kset glue_dirs;
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struct class *class;
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};
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#define to_subsys_private(obj) container_of(obj, struct subsys_private, subsys.kobj)
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struct driver_private {
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struct kobject kobj;
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struct klist klist_devices;
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struct klist_node knode_bus;
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struct module_kobject *mkobj;
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struct device_driver *driver;
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};
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#define to_driver(obj) container_of(obj, struct driver_private, kobj)
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/**
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* struct device_private - structure to hold the private to the driver core portions of the device structure.
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*
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* @klist_children - klist containing all children of this device
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* @knode_parent - node in sibling list
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* @knode_driver - node in driver list
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* @knode_bus - node in bus list
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* @driver_data - private pointer for driver specific info. Will turn into a
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* list soon.
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* @device - pointer back to the struct class that this structure is
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* associated with.
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*
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* Nothing outside of the driver core should ever touch these fields.
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*/
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struct device_private {
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struct klist klist_children;
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struct klist_node knode_parent;
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struct klist_node knode_driver;
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struct klist_node knode_bus;
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void *driver_data;
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struct device *device;
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};
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#define to_device_private_parent(obj) \
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container_of(obj, struct device_private, knode_parent)
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#define to_device_private_driver(obj) \
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container_of(obj, struct device_private, knode_driver)
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#define to_device_private_bus(obj) \
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container_of(obj, struct device_private, knode_bus)
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extern int device_private_init(struct device *dev);
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/* initialisation functions */
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extern int devices_init(void);
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extern int buses_init(void);
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extern int classes_init(void);
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extern int firmware_init(void);
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#ifdef CONFIG_SYS_HYPERVISOR
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extern int hypervisor_init(void);
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#else
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static inline int hypervisor_init(void) { return 0; }
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#endif
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extern int platform_bus_init(void);
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extern void cpu_dev_init(void);
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extern int bus_add_device(struct device *dev);
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extern void bus_probe_device(struct device *dev);
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extern void bus_remove_device(struct device *dev);
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extern int bus_add_driver(struct device_driver *drv);
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extern void bus_remove_driver(struct device_driver *drv);
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extern void driver_detach(struct device_driver *drv);
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extern int driver_probe_device(struct device_driver *drv, struct device *dev);
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extern void driver_deferred_probe_del(struct device *dev);
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static inline int driver_match_device(struct device_driver *drv,
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struct device *dev)
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{
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return drv->bus->match ? drv->bus->match(dev, drv) : 1;
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}
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extern char *make_class_name(const char *name, struct kobject *kobj);
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extern int devres_release_all(struct device *dev);
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/* /sys/devices directory */
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extern struct kset *devices_kset;
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#if defined(CONFIG_MODULES) && defined(CONFIG_SYSFS)
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extern void module_add_driver(struct module *mod, struct device_driver *drv);
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extern void module_remove_driver(struct device_driver *drv);
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#else
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static inline void module_add_driver(struct module *mod,
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struct device_driver *drv) { }
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static inline void module_remove_driver(struct device_driver *drv) { }
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#endif
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#ifdef CONFIG_DEVTMPFS
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extern int devtmpfs_init(void);
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#else
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static inline int devtmpfs_init(void) { return 0; }
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#endif
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