Adds API that allows callers to find out what other firmware nodes a node depends on.
Implementors of bindings documentation can register callbacks that return the dependencies of a node.
Dependency information can be used to change the order in which devices are probed, or to print a warning when a device node is going to be probed without all its dependencies fulfilled.
Signed-off-by: Tomeu Vizoso tomeu.vizoso@collabora.com ---
Changes in v2: - Allow bindings implementations register a function instead of using class callbacks, as not only subsystems implement firmware bindings.
drivers/base/property.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fwnode.h | 5 +++ include/linux/property.h | 12 +++++++ 3 files changed, 108 insertions(+)
diff --git a/drivers/base/property.c b/drivers/base/property.c index 8ead1ba..9d38ede 100644 --- a/drivers/base/property.c +++ b/drivers/base/property.c @@ -19,7 +19,13 @@ #include <linux/platform_device.h> #include <linux/property.h>
+struct dependency_parser { + struct list_head parser; + void (*func)(struct fwnode_handle *fwnode, struct list_head *deps); +}; + static bool fwnode_match_enable = false; +static LIST_HEAD(dependency_parsers);
/** * device_add_property_set - Add a collection of properties to a device object. @@ -553,6 +559,27 @@ bool device_dma_is_coherent(struct device *dev) EXPORT_SYMBOL_GPL(device_dma_is_coherent);
/** + * fwnode_add_dependency - add firmware node to the passed dependency list + * @fwnode: Firmware node to add to dependency list + * @list: Dependency list to add the fwnode to + */ +void fwnode_add_dependency(struct fwnode_handle *fwnode, + struct list_head *list) +{ + struct fwnode_dependency *dep; + + dep = kzalloc(sizeof(*dep), GFP_KERNEL); + if (!dep) + return; + + INIT_LIST_HEAD(&dep->dependency); + dep->fwnode = fwnode; + + list_add_tail(&dep->dependency, list); +} +EXPORT_SYMBOL_GPL(fwnode_add_dependency); + +/** * fwnode_get_parent - return the parent node of a device node * @fwnode: Device node to find the parent node of */ @@ -600,6 +627,70 @@ bool fwnode_is_compatible(struct fwnode_handle *fwnode, const char *compatible) EXPORT_SYMBOL_GPL(fwnode_is_compatible);
/** + * fwnode_add_dependency_parser - register dependency parser + * @func: Function that will be called to find out dependencies of a node + * + * Registers a callback that will be called when collecting the dependencies + * of a firmware node. The callback should inspect the properties of the node + * and call fwnode_add_dependency() for each dependency it recognizes, from + * the bindings documentation. + */ +void fwnode_add_dependency_parser( + void (*func)(struct fwnode_handle *fwnode, struct list_head *deps)) +{ + struct dependency_parser *parser; + + parser = kzalloc(sizeof(*parser), GFP_KERNEL); + if (!parser) + return; + + INIT_LIST_HEAD(&parser->parser); + parser->func = func; + + list_add_tail(&parser->parser, &dependency_parsers); +} +EXPORT_SYMBOL_GPL(fwnode_add_dependency_parser); + +/** + * fwnode_remove_dependency_parser - unregister dependency parser + * @func: Function that was to be called to find out dependencies of a node + */ +void fwnode_remove_dependency_parser( + void (*func)(struct fwnode_handle *fwnode, struct list_head *deps)) +{ + struct dependency_parser *parser, *tmp; + + list_for_each_entry_safe(parser, tmp, &dependency_parsers, parser) { + if (parser->func == func) { + list_del(&parser->parser); + kfree(parser); + return; + } + } +} +EXPORT_SYMBOL_GPL(fwnode_remove_dependency_parser); + +/** + * fwnode_get_dependencies - find out what dependencies a firmware node has + * @fwnode: firmware node to find its dependencies + * @deps: list of struct fwnode_dependency in which dependencies will be placed + */ +void fwnode_get_dependencies(struct fwnode_handle *fwnode, + struct list_head *deps) +{ + struct dependency_parser *parser; + struct fwnode_handle *child; + + list_for_each_entry(parser, &dependency_parsers, parser) + parser->func(fwnode, deps); + + /* Some device nodes will have dependencies in non-device sub-nodes */ + fwnode_for_each_child_node(fwnode, child) + if (!fwnode_property_present(child, "compatible")) + fwnode_get_dependencies(child, deps); +} + +/** * fwnode_driver_match_device - Tell if a driver matches a device. * @drv: the device_driver structure to test * @dev: the device structure to match against diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index 0408545..68ab558 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -24,4 +24,9 @@ struct fwnode_handle { struct fwnode_handle *secondary; };
+struct fwnode_dependency { + struct fwnode_handle *fwnode; + struct list_head dependency; +}; + #endif diff --git a/include/linux/property.h b/include/linux/property.h index 4e453c4..b8b86ea 100644 --- a/include/linux/property.h +++ b/include/linux/property.h @@ -86,6 +86,18 @@ bool fwnode_is_compatible(struct fwnode_handle *fwnode, const char *compatible); bool fwnode_driver_match_device(struct device *dev, const struct device_driver *drv);
+void fwnode_add_dependency(struct fwnode_handle *fwnode, + struct list_head *list); + +void fwnode_add_dependency_parser( + void (*func)(struct fwnode_handle *fwnode, struct list_head *deps)); + +void fwnode_remove_dependency_parser( + void (*func)(struct fwnode_handle *fwnode, struct list_head *deps)); + +void fwnode_get_dependencies(struct fwnode_handle *fwnode, + struct list_head *list); + unsigned int device_get_child_node_count(struct device *dev);
static inline bool device_property_read_bool(struct device *dev,