From e7dd40105aac9ba051e44ad711123bc53a5e4c71 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 1 Feb 2019 01:59:42 +0100 Subject: [PATCH] driver core: Add device link flag DL_FLAG_AUTOPROBE_CONSUMER Add a new device link flag, DL_FLAG_AUTOPROBE_CONSUMER, to request the driver core to probe for a consumer driver automatically after binding a driver to the supplier device on a persistent managed device link. As unbinding the supplier driver on a managed device link causes the consumer driver to be detached from its device automatically, this flag provides a complementary mechanism which is needed to address some "composite device" use cases. Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- Documentation/driver-api/device_link.rst | 9 +++++++++ drivers/base/core.c | 16 +++++++++++++++- drivers/base/dd.c | 2 +- include/linux/device.h | 3 +++ 4 files changed, 28 insertions(+), 2 deletions(-) diff --git a/Documentation/driver-api/device_link.rst b/Documentation/driver-api/device_link.rst index e249e074a8d2..c764755121c7 100644 --- a/Documentation/driver-api/device_link.rst +++ b/Documentation/driver-api/device_link.rst @@ -94,6 +94,15 @@ Similarly, when the device link is added from supplier's ``->probe`` callback, ``DL_FLAG_AUTOREMOVE_SUPPLIER`` causes the device link to be automatically purged when the supplier fails to probe or later unbinds. +If neither ``DL_FLAG_AUTOREMOVE_CONSUMER`` nor ``DL_FLAG_AUTOREMOVE_SUPPLIER`` +is set, ``DL_FLAG_AUTOPROBE_CONSUMER`` can be used to request the driver core +to probe for a driver for the consumer driver on the link automatically after +a driver has been bound to the supplier device. + +Note, however, that any combinations of ``DL_FLAG_AUTOREMOVE_CONSUMER``, +``DL_FLAG_AUTOREMOVE_SUPPLIER`` or ``DL_FLAG_AUTOPROBE_CONSUMER`` with +``DL_FLAG_STATELESS`` are invalid and cannot be used. + Limitations =========== diff --git a/drivers/base/core.c b/drivers/base/core.c index 9d49b461b1d9..abfce4f613f8 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -208,6 +208,12 @@ static void device_link_rpm_prepare(struct device *consumer, * the link will be maintained until one of the devices pointed to by it (either * the consumer or the supplier) is unregistered. * + * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and + * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent + * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can + * be used to request the driver core to automaticall probe for a consmer + * driver after successfully binding a driver to the supplier device. + * * The combination of DL_FLAG_STATELESS and either DL_FLAG_AUTOREMOVE_CONSUMER * or DL_FLAG_AUTOREMOVE_SUPPLIER set in @flags at the same time is invalid and * will cause NULL to be returned upfront. @@ -228,7 +234,12 @@ struct device_link *device_link_add(struct device *consumer, if (!consumer || !supplier || (flags & DL_FLAG_STATELESS && - flags & (DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER))) + flags & (DL_FLAG_AUTOREMOVE_CONSUMER | + DL_FLAG_AUTOREMOVE_SUPPLIER | + DL_FLAG_AUTOPROBE_CONSUMER)) || + (flags & DL_FLAG_AUTOPROBE_CONSUMER && + flags & (DL_FLAG_AUTOREMOVE_CONSUMER | + DL_FLAG_AUTOREMOVE_SUPPLIER))) return NULL; if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) { @@ -589,6 +600,9 @@ void device_links_driver_bound(struct device *dev) WARN_ON(link->status != DL_STATE_DORMANT); WRITE_ONCE(link->status, DL_STATE_AVAILABLE); + + if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER) + driver_deferred_probe_add(link->consumer); } list_for_each_entry(link, &dev->links.suppliers, c_node) { diff --git a/drivers/base/dd.c b/drivers/base/dd.c index aa6a9c613595..2e898cbba79b 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -116,7 +116,7 @@ static void deferred_probe_work_func(struct work_struct *work) } static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); -static void driver_deferred_probe_add(struct device *dev) +void driver_deferred_probe_add(struct device *dev) { mutex_lock(&deferred_probe_mutex); if (list_empty(&dev->p->deferred_probe)) { diff --git a/include/linux/device.h b/include/linux/device.h index 5f49d2eff6ed..0ab0a3a80ec3 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -341,6 +341,7 @@ struct device *driver_find_device(struct device_driver *drv, struct device *start, void *data, int (*match)(struct device *dev, void *data)); +void driver_deferred_probe_add(struct device *dev); int driver_deferred_probe_check_state(struct device *dev); /** @@ -827,12 +828,14 @@ enum device_link_state { * PM_RUNTIME: If set, the runtime PM framework will use this link. * RPM_ACTIVE: Run pm_runtime_get_sync() on the supplier during link creation. * AUTOREMOVE_SUPPLIER: Remove the link automatically on supplier driver unbind. + * AUTOPROBE_CONSUMER: Probe consumer driver automatically after supplier binds. */ #define DL_FLAG_STATELESS BIT(0) #define DL_FLAG_AUTOREMOVE_CONSUMER BIT(1) #define DL_FLAG_PM_RUNTIME BIT(2) #define DL_FLAG_RPM_ACTIVE BIT(3) #define DL_FLAG_AUTOREMOVE_SUPPLIER BIT(4) +#define DL_FLAG_AUTOPROBE_CONSUMER BIT(5) /** * struct device_link - Device link representation. -- 2.34.1