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driver core: Allow a device to wait on optional suppliers
Before this change, if a device is waiting on suppliers, it's assumed that all those suppliers are needed for the device to probe successfully. This change allows marking a devices as waiting only on optional suppliers. This allows a device to wait on suppliers (and link to them as soon as they are available) without preventing the device from being probed. Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20191028220027.251605-3-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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05ef983e0d
commit
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2 changed files with 28 additions and 3 deletions
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@ -480,13 +480,25 @@ EXPORT_SYMBOL_GPL(device_link_add);
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* This function is NOT meant to be called from the probe function of the
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* This function is NOT meant to be called from the probe function of the
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* consumer but rather from code that creates/adds the consumer device.
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* consumer but rather from code that creates/adds the consumer device.
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*/
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*/
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static void device_link_wait_for_supplier(struct device *consumer)
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static void device_link_wait_for_supplier(struct device *consumer,
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bool need_for_probe)
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{
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{
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mutex_lock(&wfs_lock);
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mutex_lock(&wfs_lock);
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list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);
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list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);
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consumer->links.need_for_probe = need_for_probe;
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mutex_unlock(&wfs_lock);
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mutex_unlock(&wfs_lock);
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}
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}
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static void device_link_wait_for_mandatory_supplier(struct device *consumer)
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{
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device_link_wait_for_supplier(consumer, true);
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}
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static void device_link_wait_for_optional_supplier(struct device *consumer)
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{
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device_link_wait_for_supplier(consumer, false);
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}
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/**
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/**
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* device_link_add_missing_supplier_links - Add links from consumer devices to
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* device_link_add_missing_supplier_links - Add links from consumer devices to
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* supplier devices, leaving any
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* supplier devices, leaving any
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@ -656,7 +668,8 @@ int device_links_check_suppliers(struct device *dev)
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* probe.
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* probe.
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*/
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*/
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mutex_lock(&wfs_lock);
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mutex_lock(&wfs_lock);
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if (!list_empty(&dev->links.needs_suppliers)) {
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if (!list_empty(&dev->links.needs_suppliers) &&
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dev->links.need_for_probe) {
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mutex_unlock(&wfs_lock);
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mutex_unlock(&wfs_lock);
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return -EPROBE_DEFER;
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return -EPROBE_DEFER;
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}
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}
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@ -760,6 +773,15 @@ void device_links_driver_bound(struct device *dev)
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{
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{
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struct device_link *link;
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struct device_link *link;
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/*
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* If a device probes successfully, it's expected to have created all
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* the device links it needs to or make new device links as it needs
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* them. So, it no longer needs to wait on any suppliers.
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*/
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mutex_lock(&wfs_lock);
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list_del_init(&dev->links.needs_suppliers);
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mutex_unlock(&wfs_lock);
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device_links_write_lock();
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device_links_write_lock();
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list_for_each_entry(link, &dev->links.consumers, s_node) {
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list_for_each_entry(link, &dev->links.consumers, s_node) {
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@ -2393,7 +2415,7 @@ int device_add(struct device *dev)
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if (fwnode_has_op(dev->fwnode, add_links)
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if (fwnode_has_op(dev->fwnode, add_links)
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&& fwnode_call_int_op(dev->fwnode, add_links, dev))
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&& fwnode_call_int_op(dev->fwnode, add_links, dev))
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device_link_wait_for_supplier(dev);
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device_link_wait_for_mandatory_supplier(dev, true);
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bus_probe_device(dev);
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bus_probe_device(dev);
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if (parent)
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if (parent)
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@ -1155,6 +1155,8 @@ enum dl_dev_state {
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* @consumers: List of links to consumer devices.
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* @consumers: List of links to consumer devices.
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* @needs_suppliers: Hook to global list of devices waiting for suppliers.
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* @needs_suppliers: Hook to global list of devices waiting for suppliers.
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* @defer_sync: Hook to global list of devices that have deferred sync_state.
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* @defer_sync: Hook to global list of devices that have deferred sync_state.
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* @need_for_probe: If needs_suppliers is on a list, this indicates if the
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* suppliers are needed for probe or not.
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* @status: Driver status information.
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* @status: Driver status information.
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*/
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*/
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struct dev_links_info {
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struct dev_links_info {
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@ -1162,6 +1164,7 @@ struct dev_links_info {
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struct list_head consumers;
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struct list_head consumers;
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struct list_head needs_suppliers;
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struct list_head needs_suppliers;
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struct list_head defer_sync;
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struct list_head defer_sync;
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bool need_for_probe;
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enum dl_dev_state status;
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enum dl_dev_state status;
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};
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};
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