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@xxxxxxxxxxxxx>
---
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,
--
2.4.1
--
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