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driver core: Expose device link details in sysfs

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It's helpful to be able to look at device link details from sysfs. So,
expose it in sysfs.

Say device-A is supplier of device-B. These are the additional files
this patch would create:

/sys/class/devlink/device-A:device-B/
	auto_remove_on
	consumer/ -> .../device-B/
	runtime_pm
	status
	supplier/ -> .../device-A/
	sync_state_only

/sys/devices/.../device-A/
	consumer:device-B/ -> /sys/class/devlink/device-A:device-B/

/sys/devices/.../device-B/
	supplier:device-A/ -> /sys/class/devlink/device-A:device-B/

That way:
To get a list of all the device link in the system:
ls /sys/class/devlink/

To get the consumer names and links of a device:
ls -d /sys/devices/.../device-X/consumer:*

To get the supplier names and links of a device:
ls -d /sys/devices/.../device-X/supplier:*

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200521191800.136035-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Saravana Kannan
2020-05-21 12:17:58 -07:00
committed by Greg Kroah-Hartman
parent fe940d7362
commit 287905e68d
5 changed files with 375 additions and 36 deletions
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58
include/linux/device.h
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@@ -386,34 +386,6 @@ enum device_link_state {
#define DL_FLAG_MANAGED BIT(6)
#define DL_FLAG_SYNC_STATE_ONLY BIT(7)
/**
* struct device_link - Device link representation.
* @supplier: The device on the supplier end of the link.
* @s_node: Hook to the supplier device's list of links to consumers.
* @consumer: The device on the consumer end of the link.
* @c_node: Hook to the consumer device's list of links to suppliers.
* @status: The state of the link (with respect to the presence of drivers).
* @flags: Link flags.
* @rpm_active: Whether or not the consumer device is runtime-PM-active.
* @kref: Count repeated addition of the same link.
* @rcu_head: An RCU head to use for deferred execution of SRCU callbacks.
* @supplier_preactivated: Supplier has been made active before consumer probe.
*/
struct device_link {
struct device *supplier;
struct list_head s_node;
struct device *consumer;
struct list_head c_node;
enum device_link_state status;
u32 flags;
refcount_t rpm_active;
struct kref kref;
#ifdef CONFIG_SRCU
struct rcu_head rcu_head;
#endif
bool supplier_preactivated; /* Owned by consumer probe. */
};
/**
* enum dl_dev_state - Device driver presence tracking information.
* @DL_DEV_NO_DRIVER: There is no driver attached to the device.
@@ -624,6 +596,36 @@ struct device {
#endif
};
/**
* struct device_link - Device link representation.
* @supplier: The device on the supplier end of the link.
* @s_node: Hook to the supplier device's list of links to consumers.
* @consumer: The device on the consumer end of the link.
* @c_node: Hook to the consumer device's list of links to suppliers.
* @link_dev: device used to expose link details in sysfs
* @status: The state of the link (with respect to the presence of drivers).
* @flags: Link flags.
* @rpm_active: Whether or not the consumer device is runtime-PM-active.
* @kref: Count repeated addition of the same link.
* @rcu_head: An RCU head to use for deferred execution of SRCU callbacks.
* @supplier_preactivated: Supplier has been made active before consumer probe.
*/
struct device_link {
struct device *supplier;
struct list_head s_node;
struct device *consumer;
struct list_head c_node;
struct device link_dev;
enum device_link_state status;
u32 flags;
refcount_t rpm_active;
struct kref kref;
#ifdef CONFIG_SRCU
struct rcu_head rcu_head;
#endif
bool supplier_preactivated; /* Owned by consumer probe. */
};
static inline struct device *kobj_to_dev(struct kobject *kobj)
{
return container_of(kobj, struct device, kobj);