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driver core: Redefine the meaning of fwnode_operations.add_links()

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Change the meaning of fwnode_operations.add_links() to just create
fwnode links by parsing the properties of a given fwnode.

This patch doesn't actually make any code changes. To keeps things more
digestable, the actual functional changes come in later patches in this
series.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-12-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Saravana Kannan 2020-11-20 18:02:26 -08:00 committed by Greg Kroah-Hartman
parent b5d3e2fbcb
commit 04f63c213b
2 changed files with 4 additions and 40 deletions
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2
drivers/firmware/efi/efi-init.c
View file

@ -316,7 +316,7 @@ static struct device_node *find_pci_overlap_node(void)
* resource reservation conflict on the memory window that the efifb
* framebuffer steals from the PCIe host bridge.
*/
static int efifb_add_links(const struct fwnode_handle *fwnode,
static int efifb_add_links(struct fwnode_handle *fwnode,
struct device *dev)
{
struct device_node *sup_np;

42
include/linux/fwnode.h
View file

@ -78,44 +78,8 @@ struct fwnode_reference_args {
* endpoint node.
* @graph_get_port_parent: Return the parent node of a port node.
* @graph_parse_endpoint: Parse endpoint for port and endpoint id.
* @add_links: Called after the device corresponding to the fwnode is added
* using device_add(). The function is expected to create device
* links to all the suppliers of the device that are available at
* the time this function is called. The function must NOT stop
* at the first failed device link if other unlinked supplier
* devices are present in the system. This is necessary for the
* driver/bus sync_state() callbacks to work correctly.
*
* For example, say Device-C depends on suppliers Device-S1 and
* Device-S2 and the dependency is listed in that order in the
* firmware. Say, S1 gets populated from the firmware after
* late_initcall_sync(). Say S2 is populated and probed way
* before that in device_initcall(). When C is populated, if this
* add_links() function doesn't continue past a "failed linking to
* S1" and continue linking C to S2, then S2 will get a
* sync_state() callback before C is probed. This is because from
* the perspective of S2, C was never a consumer when its
* sync_state() evaluation is done. To avoid this, the add_links()
* function has to go through all available suppliers of the
* device (that corresponds to this fwnode) and link to them
* before returning.
*
* If some suppliers are not yet available (indicated by an error
* return value), this function will be called again when other
* devices are added to allow creating device links to any newly
* available suppliers.
*
* Return 0 if device links have been successfully created to all
* the known suppliers of this device or if the supplier
* information is not known.
*
* Return -ENODEV if the suppliers needed for probing this device
* have not been registered yet (because device links can only be
* created to devices registered with the driver core).
*
* Return -EAGAIN if some of the suppliers of this device have not
* been registered yet, but none of those suppliers are necessary
* for probing the device.
* @add_links: Create fwnode links to all the suppliers of the fwnode. Return
* zero on success, a negative error code otherwise.
*/
struct fwnode_operations {
struct fwnode_handle *(*get)(struct fwnode_handle *fwnode);
@ -155,7 +119,7 @@ struct fwnode_operations {
(*graph_get_port_parent)(struct fwnode_handle *fwnode);
int (*graph_parse_endpoint)(const struct fwnode_handle *fwnode,
struct fwnode_endpoint *endpoint);
int (*add_links)(const struct fwnode_handle *fwnode,
int (*add_links)(struct fwnode_handle *fwnode,
struct device *dev);
};