Add a new (optional) field to denote the physical location of a device in the system, and expose it in sysfs. This was discussed here: https://lore.kernel.org/linux-acpi/20200618184621.GA446639@xxxxxxxxx/ (The primary choice for attribute name i.e. "location" is already exposed as an ABI elsewhere, so settled for "site"). Individual buses that want to support this new attribute can opt-in by setting a flag in bus_type, and then populating the location of device while enumerating it. Signed-off-by: Rajat Jain <rajatja@xxxxxxxxxx> --- v2: (Initial version) drivers/base/core.c | 35 +++++++++++++++++++++++++++++++ include/linux/device.h | 42 ++++++++++++++++++++++++++++++++++++++ include/linux/device/bus.h | 8 ++++++++ 3 files changed, 85 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index 67d39a90b45c7..14c815526b7fa 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1778,6 +1778,32 @@ static ssize_t online_store(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RW(online); +static ssize_t site_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + const char *site; + + device_lock(dev); + switch (dev->site) { + case SITE_INTERNAL: + site = "INTERNAL"; + break; + case SITE_EXTENDED: + site = "EXTENDED"; + break; + case SITE_EXTERNAL: + site = "EXTERNAL"; + break; + case SITE_UNKNOWN: + default: + site = "UNKNOWN"; + break; + } + device_unlock(dev); + return sprintf(buf, "%s\n", site); +} +static DEVICE_ATTR_RO(site); + int device_add_groups(struct device *dev, const struct attribute_group **groups) { return sysfs_create_groups(&dev->kobj, groups); @@ -1949,8 +1975,16 @@ static int device_add_attrs(struct device *dev) goto err_remove_dev_groups; } + if (bus_supports_site(dev->bus)) { + error = device_create_file(dev, &dev_attr_site); + if (error) + goto err_remove_dev_attr_online; + } + return 0; + err_remove_dev_attr_online: + device_remove_file(dev, &dev_attr_online); err_remove_dev_groups: device_remove_groups(dev, dev->groups); err_remove_type_groups: @@ -1968,6 +2002,7 @@ static void device_remove_attrs(struct device *dev) struct class *class = dev->class; const struct device_type *type = dev->type; + device_remove_file(dev, &dev_attr_site); device_remove_file(dev, &dev_attr_online); device_remove_groups(dev, dev->groups); diff --git a/include/linux/device.h b/include/linux/device.h index 15460a5ac024a..a4143735ae712 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -428,6 +428,31 @@ enum dl_dev_state { DL_DEV_UNBINDING, }; +/** + * enum device_site - Physical location of the device in the system. + * The semantics of values depend on subsystem / bus: + * + * @SITE_UNKNOWN: Location is Unknown (default) + * + * @SITE_INTERNAL: Device is internal to the system, and cannot be (easily) + * removed. E.g. SoC internal devices, onboard soldered + * devices, internal M.2 cards (that cannot be removed + * without opening the chassis). + * @SITE_EXTENDED: Device sits an extension of the system. E.g. devices + * on external PCIe trays, docking stations etc. These + * devices may be removable, but are generally housed + * internally on an extension board, so they are removed + * only when that whole extension board is removed. + * @SITE_EXTERNAL: Devices truly external to the system (i.e. plugged on + * an external port) that may be removed or added frequently. + */ +enum device_site { + SITE_UNKNOWN = 0, + SITE_INTERNAL, + SITE_EXTENDED, + SITE_EXTERNAL, +}; + /** * struct dev_links_info - Device data related to device links. * @suppliers: List of links to supplier devices. @@ -513,6 +538,7 @@ struct dev_links_info { * device (i.e. the bus driver that discovered the device). * @iommu_group: IOMMU group the device belongs to. * @iommu: Per device generic IOMMU runtime data + * @site: Physical location of the device w.r.t. the system * * @offline_disabled: If set, the device is permanently online. * @offline: Set after successful invocation of bus type's .offline(). @@ -613,6 +639,8 @@ struct device { struct iommu_group *iommu_group; struct dev_iommu *iommu; + enum device_site site; /* Device physical location */ + bool offline_disabled:1; bool offline:1; bool of_node_reused:1; @@ -806,6 +834,20 @@ static inline bool dev_has_sync_state(struct device *dev) return false; } +static inline int dev_set_site(struct device *dev, enum device_site site) +{ + if (site < SITE_UNKNOWN || site > SITE_EXTERNAL) + return -EINVAL; + + dev->site = site; + return 0; +} + +static inline bool dev_is_external(struct device *dev) +{ + return dev->site == SITE_EXTERNAL; +} + /* * High level routines for use by the bus drivers */ diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h index 1ea5e1d1545bd..e1079772e45af 100644 --- a/include/linux/device/bus.h +++ b/include/linux/device/bus.h @@ -69,6 +69,8 @@ struct fwnode_handle; * @lock_key: Lock class key for use by the lock validator * @need_parent_lock: When probing or removing a device on this bus, the * device core should lock the device's parent. + * @supports_site: Bus can differentiate between internal/external devices + * and thus supports the device "site" attribute. * * A bus is a channel between the processor and one or more devices. For the * purposes of the device model, all devices are connected via a bus, even if @@ -112,6 +114,7 @@ struct bus_type { struct lock_class_key lock_key; bool need_parent_lock; + bool supports_site; }; extern int __must_check bus_register(struct bus_type *bus); @@ -246,6 +249,11 @@ bus_find_device_by_acpi_dev(struct bus_type *bus, const void *adev) } #endif +static inline bool bus_supports_site(struct bus_type *bus) +{ + return bus && bus->supports_site; +} + struct device *subsys_find_device_by_id(struct bus_type *bus, unsigned int id, struct device *hint); int bus_for_each_drv(struct bus_type *bus, struct device_driver *start, -- 2.27.0.212.ge8ba1cc988-goog
