From e2ae9bcc4aaacda04edb75c4eea93384719efaa5 Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Wed, 4 Sep 2019 14:11:21 -0700 Subject: driver core: Add support for linking devices during device addition The firmware corresponding to a device (dev.fwnode) might be able to provide functional dependency information between a device and its supplier and consumer devices. Tracking this functional dependency allows optimizing device probe order and informing a supplier when all its consumers have probed (and thereby actively managing their resources). The existing device links feature allows tracking and using supplier-consumer relationships. So, this patch adds the add_links() fwnode callback to allow firmware to create device links for each device as the device is added. However, when consumer devices are added, they might not have a supplier device to link to despite needing mandatory resources/functionality from one or more suppliers. A waiting_for_suppliers list is created to track such consumers and retry linking them when new devices get added. Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20190904211126.47518-3-saravanak@google.com Signed-off-by: Greg Kroah-Hartman --- include/linux/device.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/device.h') diff --git a/include/linux/device.h b/include/linux/device.h index 297239a08bb7..c6fb5b3431b7 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1135,11 +1135,13 @@ enum dl_dev_state { * struct dev_links_info - Device data related to device links. * @suppliers: List of links to supplier devices. * @consumers: List of links to consumer devices. + * @needs_suppliers: Hook to global list of devices waiting for suppliers. * @status: Driver status information. */ struct dev_links_info { struct list_head suppliers; struct list_head consumers; + struct list_head needs_suppliers; enum dl_dev_state status; }; -- cgit v1.2.3