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![Saravana Kannan](/assets/img/avatar_default.png)
fwnode_operations.add_links allows creating device links from information provided by firmware. fwnode_operations.add_links is currently implemented only by OF/devicetree code and a specific case of efi. However, there's nothing preventing ACPI or other firmware types from implementing it. The OF implementation is currently controlled by a kernel commandline parameter called of_devlink. Since this feature is generic isn't limited to OF, add a generic fw_devlink kernel commandline parameter to control this feature across firmware types. Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20200222014038.180923-3-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
175 lines
6.9 KiB
C
175 lines
6.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* fwnode.h - Firmware device node object handle type definition.
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*
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* Copyright (C) 2015, Intel Corporation
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* Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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*/
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#ifndef _LINUX_FWNODE_H_
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#define _LINUX_FWNODE_H_
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#include <linux/types.h>
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struct fwnode_operations;
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struct device;
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struct fwnode_handle {
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struct fwnode_handle *secondary;
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const struct fwnode_operations *ops;
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struct device *dev;
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};
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/**
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* struct fwnode_endpoint - Fwnode graph endpoint
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* @port: Port number
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* @id: Endpoint id
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* @local_fwnode: reference to the related fwnode
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*/
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struct fwnode_endpoint {
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unsigned int port;
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unsigned int id;
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const struct fwnode_handle *local_fwnode;
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};
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#define NR_FWNODE_REFERENCE_ARGS 8
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/**
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* struct fwnode_reference_args - Fwnode reference with additional arguments
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* @fwnode:- A reference to the base fwnode
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* @nargs: Number of elements in @args array
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* @args: Integer arguments on the fwnode
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*/
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struct fwnode_reference_args {
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struct fwnode_handle *fwnode;
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unsigned int nargs;
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u64 args[NR_FWNODE_REFERENCE_ARGS];
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};
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/**
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* struct fwnode_operations - Operations for fwnode interface
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* @get: Get a reference to an fwnode.
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* @put: Put a reference to an fwnode.
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* @device_is_available: Return true if the device is available.
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* @device_get_match_data: Return the device driver match data.
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* @property_present: Return true if a property is present.
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* @property_read_int_array: Read an array of integer properties. Return zero on
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* success, a negative error code otherwise.
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* @property_read_string_array: Read an array of string properties. Return zero
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* on success, a negative error code otherwise.
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* @get_name: Return the name of an fwnode.
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* @get_name_prefix: Get a prefix for a node (for printing purposes).
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* @get_parent: Return the parent of an fwnode.
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* @get_next_child_node: Return the next child node in an iteration.
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* @get_named_child_node: Return a child node with a given name.
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* @get_reference_args: Return a reference pointed to by a property, with args
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* @graph_get_next_endpoint: Return an endpoint node in an iteration.
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* @graph_get_remote_endpoint: Return the remote endpoint node of a local
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* endpoint node.
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* @graph_get_port_parent: Return the parent node of a port node.
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* @graph_parse_endpoint: Parse endpoint for port and endpoint id.
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* @add_links: Called after the device corresponding to the fwnode is added
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* using device_add(). The function is expected to create device
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* links to all the suppliers of the device that are available at
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* the time this function is called. The function must NOT stop
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* at the first failed device link if other unlinked supplier
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* devices are present in the system. This is necessary for the
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* driver/bus sync_state() callbacks to work correctly.
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*
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* For example, say Device-C depends on suppliers Device-S1 and
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* Device-S2 and the dependency is listed in that order in the
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* firmware. Say, S1 gets populated from the firmware after
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* late_initcall_sync(). Say S2 is populated and probed way
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* before that in device_initcall(). When C is populated, if this
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* add_links() function doesn't continue past a "failed linking to
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* S1" and continue linking C to S2, then S2 will get a
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* sync_state() callback before C is probed. This is because from
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* the perspective of S2, C was never a consumer when its
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* sync_state() evaluation is done. To avoid this, the add_links()
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* function has to go through all available suppliers of the
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* device (that corresponds to this fwnode) and link to them
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* before returning.
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*
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* If some suppliers are not yet available (indicated by an error
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* return value), this function will be called again when other
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* devices are added to allow creating device links to any newly
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* available suppliers.
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*
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* Return 0 if device links have been successfully created to all
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* the known suppliers of this device or if the supplier
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* information is not known.
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*
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* Return -ENODEV if the suppliers needed for probing this device
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* have not been registered yet (because device links can only be
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* created to devices registered with the driver core).
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*
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* Return -EAGAIN if some of the suppliers of this device have not
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* been registered yet, but none of those suppliers are necessary
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* for probing the device.
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*/
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struct fwnode_operations {
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struct fwnode_handle *(*get)(struct fwnode_handle *fwnode);
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void (*put)(struct fwnode_handle *fwnode);
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bool (*device_is_available)(const struct fwnode_handle *fwnode);
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const void *(*device_get_match_data)(const struct fwnode_handle *fwnode,
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const struct device *dev);
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bool (*property_present)(const struct fwnode_handle *fwnode,
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const char *propname);
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int (*property_read_int_array)(const struct fwnode_handle *fwnode,
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const char *propname,
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unsigned int elem_size, void *val,
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size_t nval);
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int
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(*property_read_string_array)(const struct fwnode_handle *fwnode_handle,
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const char *propname, const char **val,
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size_t nval);
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const char *(*get_name)(const struct fwnode_handle *fwnode);
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const char *(*get_name_prefix)(const struct fwnode_handle *fwnode);
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struct fwnode_handle *(*get_parent)(const struct fwnode_handle *fwnode);
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struct fwnode_handle *
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(*get_next_child_node)(const struct fwnode_handle *fwnode,
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struct fwnode_handle *child);
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struct fwnode_handle *
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(*get_named_child_node)(const struct fwnode_handle *fwnode,
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const char *name);
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int (*get_reference_args)(const struct fwnode_handle *fwnode,
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const char *prop, const char *nargs_prop,
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unsigned int nargs, unsigned int index,
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struct fwnode_reference_args *args);
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struct fwnode_handle *
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(*graph_get_next_endpoint)(const struct fwnode_handle *fwnode,
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struct fwnode_handle *prev);
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struct fwnode_handle *
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(*graph_get_remote_endpoint)(const struct fwnode_handle *fwnode);
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struct fwnode_handle *
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(*graph_get_port_parent)(struct fwnode_handle *fwnode);
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int (*graph_parse_endpoint)(const struct fwnode_handle *fwnode,
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struct fwnode_endpoint *endpoint);
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int (*add_links)(const struct fwnode_handle *fwnode,
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struct device *dev);
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};
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#define fwnode_has_op(fwnode, op) \
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((fwnode) && (fwnode)->ops && (fwnode)->ops->op)
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#define fwnode_call_int_op(fwnode, op, ...) \
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(fwnode ? (fwnode_has_op(fwnode, op) ? \
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(fwnode)->ops->op(fwnode, ## __VA_ARGS__) : -ENXIO) : \
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-EINVAL)
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#define fwnode_call_bool_op(fwnode, op, ...) \
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(fwnode_has_op(fwnode, op) ? \
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(fwnode)->ops->op(fwnode, ## __VA_ARGS__) : false)
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#define fwnode_call_ptr_op(fwnode, op, ...) \
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(fwnode_has_op(fwnode, op) ? \
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(fwnode)->ops->op(fwnode, ## __VA_ARGS__) : NULL)
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#define fwnode_call_void_op(fwnode, op, ...) \
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do { \
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if (fwnode_has_op(fwnode, op)) \
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(fwnode)->ops->op(fwnode, ## __VA_ARGS__); \
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} while (false)
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#define get_dev_from_fwnode(fwnode) get_device((fwnode)->dev)
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extern u32 fw_devlink_get_flags(void);
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#endif
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