[PATCH v2 11/17] driver core: Redefine the meaning of fwnode_operations.add_links()

Saravana Kannan
2020-11-21T02:03:55Z

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>
---
drivers/firmware/efi/efi-init.c | 2 +-
include/linux/fwnode.h | 42 +++------------------------------
2 files changed, 4 insertions(+), 40 deletions(-)

diff --git a/drivers/firmware/efi/efi-init.c b/drivers/firmware/efi/efi-init.c
index b148f1459fb3..65bb97c391b0 100644
--- a/drivers/firmware/efi/efi-init.c
+++ b/drivers/firmware/efi/efi-init.c
@@ -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;
diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
index b88365187347..942a6bb18201 100644
--- a/include/linux/fwnode.h
+++ b/include/linux/fwnode.h
@@ -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);
};

--
2.29.2.454.gaff20da3a2-goog