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52cdbdd498
Now device's shutdown sequence is performed in reverse order of their
registration in devices_kset list and this sequence corresponds to the
reverse device's creation order. So, devices_kset data tracks
"parent<-child" device's dependencies only.
Unfortunately, that's not enough and causes problems in case of
implementing board's specific shutdown procedures. For example [1]:
"DRA7XX_evm uses PCF8575 and one of the PCF output lines feeds to
MMC/SD and this line should be driven high in order for the MMC/SD to
be detected. This line is modelled as regulator and the hsmmc driver
takes care of enabling and disabling it. In the case of 'reboot',
during shutdown path as part of it's cleanup process the hsmmc driver
disables this regulator. This makes MMC boot not functional."
To handle this issue the .shutdown() callback could be implemented
for PCF8575 device where corresponding GPIO pins will be configured to
states, required for correct warm/cold reset. This can be achieved
only when all .shutdown() callbacks have been called already for all
PCF8575's consumers. But devices_kset is not filled correctly now:
devices_kset: Device61 4e000000.dmm
devices_kset: Device62 48070000.i2c
devices_kset: Device63 48072000.i2c
devices_kset: Device64 48060000.i2c
devices_kset: Device65 4809c000.mmc
...
devices_kset: Device102 fixedregulator-sd
...
devices_kset: Device181 0-0020 // PCF8575
devices_kset: Device182 gpiochip496
devices_kset: Device183 0-0021 // PCF8575
devices_kset: Device184 gpiochip480
As can be seen from above .shutdown() callback for PCF8575 will be called
before its consumers, which, in turn means, that any changes of PCF8575
GPIO's pins will be or unsafe or overwritten later by GPIO's consumers.
The problem can be solved if devices_kset list will be filled not only
according device creation order, but also according device's probing
order to track "supplier<-consumer" dependencies also.
Hence, as a fix, lets add devices_kset_move_last(),
devices_kset_move_before(), devices_kset_move_after() and call them
from device_move() and also add call of devices_kset_move_last() in
really_probe(). After this change all entries in devices_kset will
be sorted according to device's creation ("parent<-child") and
probing ("supplier<-consumer") order.
devices_kset after:
devices_kset: Device121 48070000.i2c
devices_kset: Device122 i2c-0
...
devices_kset: Device147 regulator.24
devices_kset: Device148 0-0020
devices_kset: Device149 gpiochip496
devices_kset: Device150 0-0021
devices_kset: Device151 gpiochip480
devices_kset: Device152 0-0019
...
devices_kset: Device372 fixedregulator-sd
devices_kset: Device373 regulator.29
devices_kset: Device374 4809c000.mmc
devices_kset: Device375 mmc0
[1] http://www.spinics.net/lists/linux-mmc/msg29825.html
Cc: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
153 lines
5.3 KiB
C
153 lines
5.3 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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* @deferred_probe - entry in deferred_probe_list which is used to retry the
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* binding of drivers which were unable to get all the resources needed by
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* the device; typically because it depends on another driver getting
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* probed first.
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* @device - pointer back to the struct device 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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struct list_head deferred_probe;
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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 void container_dev_init(void);
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struct kobject *virtual_device_parent(struct device *dev);
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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 bool driver_allows_async_probing(struct device_driver *drv);
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extern int driver_add_groups(struct device_driver *drv,
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const struct attribute_group **groups);
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extern void driver_remove_groups(struct device_driver *drv,
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const struct attribute_group **groups);
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extern int device_add_groups(struct device *dev,
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const struct attribute_group **groups);
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extern void device_remove_groups(struct device *dev,
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const struct attribute_group **groups);
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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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extern void devices_kset_move_last(struct device *dev);
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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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