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driver core: Move the "removable" attribute from USB to core

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[ Upstream commit 70f400d4d9 ]

Move the "removable" attribute from USB to core in order to allow it to be
supported by other subsystem / buses. Individual buses that want to support
this attribute can populate the removable property of the device while
enumerating it with the 3 possible values -
 - "unknown"
 - "fixed"
 - "removable"
Leaving the field unchanged (i.e. "not supported") would mean that the
attribute would not show up in sysfs for that device. The UAPI (location,
symantics etc) for the attribute remains unchanged.

Move the "removable" attribute from USB to the device core so it can be
used by other subsystems / buses.

By default, devices do not have a "removable" attribute in sysfs.

If a subsystem or bus driver wants to support a "removable" attribute, it
should call device_set_removable() before calling device_register() or
device_add(), e.g.:

    device_set_removable(dev, DEVICE_REMOVABLE);
    device_register(dev);

The possible values and the resulting sysfs attribute contents are:

    DEVICE_REMOVABLE_UNKNOWN  ->  "unknown"
    DEVICE_REMOVABLE          ->  "removable"
    DEVICE_FIXED              ->  "fixed"

Convert the USB "removable" attribute to use this new device core
functionality.  There should be no user-visible change in the location or
semantics of attribute for USB devices.

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rajat Jain <rajatja@google.com>
Link: https://lore.kernel.org/r/20210524171812.18095-1-rajatja@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 432e664e7c ("drm/amdgpu: don't use ATRM for external devices")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Rajat Jain 2021-05-24 10:18:11 -07:00 committed by Greg Kroah-Hartman
parent 01fbfcd810
commit 2df04d76c9
7 changed files with 89 additions and 48 deletions
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11
Documentation/ABI/testing/sysfs-bus-usb
View file

@ -154,17 +154,6 @@ Description:
files hold a string value (enable or disable) indicating whether
or not USB3 hardware LPM U1 or U2 is enabled for the device.
What: /sys/bus/usb/devices/.../removable
Date: February 2012
Contact: Matthew Garrett <mjg@redhat.com>
Description:
Some information about whether a given USB device is
physically fixed to the platform can be inferred from a
combination of hub descriptor bits and platform-specific data
such as ACPI. This file will read either "removable" or
"fixed" if the information is available, and "unknown"
otherwise.
What: /sys/bus/usb/devices/.../ltm_capable
Date: July 2012
Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com>

17
Documentation/ABI/testing/sysfs-devices-removable Normal file
View file

@ -0,0 +1,17 @@
What: /sys/devices/.../removable
Date: May 2021
Contact: Rajat Jain <rajatxjain@gmail.com>
Description:
Information about whether a given device can be removed from the
platform by the user. This is determined by its subsystem in a
bus / platform-specific way. This attribute is only present for
devices that can support determining such information:
"removable": device can be removed from the platform by the user
"fixed": device is fixed to the platform / cannot be removed
by the user.
"unknown": The information is unavailable / cannot be deduced.
Currently this is only supported by USB (which infers the
information from a combination of hub descriptor bits and
platform-specific data such as ACPI).

28
drivers/base/core.c
View file

@ -2053,6 +2053,25 @@ static ssize_t online_store(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RW(online);
static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
const char *loc;
switch (dev->removable) {
case DEVICE_REMOVABLE:
loc = "removable";
break;
case DEVICE_FIXED:
loc = "fixed";
break;
default:
loc = "unknown";
}
return sysfs_emit(buf, "%s\n", loc);
}
static DEVICE_ATTR_RO(removable);
int device_add_groups(struct device *dev, const struct attribute_group **groups)
{
return sysfs_create_groups(&dev->kobj, groups);
@ -2230,8 +2249,16 @@ static int device_add_attrs(struct device *dev)
goto err_remove_dev_online;
}
if (dev_removable_is_valid(dev)) {
error = device_create_file(dev, &dev_attr_removable);
if (error)
goto err_remove_dev_waiting_for_supplier;
}
return 0;
err_remove_dev_waiting_for_supplier:
device_remove_file(dev, &dev_attr_waiting_for_supplier);
err_remove_dev_online:
device_remove_file(dev, &dev_attr_online);
err_remove_dev_groups:
@ -2251,6 +2278,7 @@ 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_removable);
device_remove_file(dev, &dev_attr_waiting_for_supplier);
device_remove_file(dev, &dev_attr_online);
device_remove_groups(dev, dev->groups);

13
drivers/usb/core/hub.c
View file

@ -2450,6 +2450,8 @@ static void set_usb_port_removable(struct usb_device *udev)
u16 wHubCharacteristics;
bool removable = true;
dev_set_removable(&udev->dev, DEVICE_REMOVABLE_UNKNOWN);
if (!hdev)
return;
@ -2461,11 +2463,11 @@ static void set_usb_port_removable(struct usb_device *udev)
*/
switch (hub->ports[udev->portnum - 1]->connect_type) {
case USB_PORT_CONNECT_TYPE_HOT_PLUG:
udev->removable = USB_DEVICE_REMOVABLE;
dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
return;
case USB_PORT_CONNECT_TYPE_HARD_WIRED:
case USB_PORT_NOT_USED:
udev->removable = USB_DEVICE_FIXED;
dev_set_removable(&udev->dev, DEVICE_FIXED);
return;
default:
break;
@ -2490,9 +2492,9 @@ static void set_usb_port_removable(struct usb_device *udev)
}
if (removable)
udev->removable = USB_DEVICE_REMOVABLE;
dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
else
udev->removable = USB_DEVICE_FIXED;
dev_set_removable(&udev->dev, DEVICE_FIXED);
}
@ -2564,8 +2566,7 @@ int usb_new_device(struct usb_device *udev)
device_enable_async_suspend(&udev->dev);
/* check whether the hub or firmware marks this port as non-removable */
if (udev->parent)
set_usb_port_removable(udev);
set_usb_port_removable(udev);
/* Register the device. The device driver is responsible
* for configuring the device and invoking the add-device

24
drivers/usb/core/sysfs.c
View file

@ -298,29 +298,6 @@ static ssize_t urbnum_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(urbnum);
static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct usb_device *udev;
char *state;
udev = to_usb_device(dev);
switch (udev->removable) {
case USB_DEVICE_REMOVABLE:
state = "removable";
break;
case USB_DEVICE_FIXED:
state = "fixed";
break;
default:
state = "unknown";
}
return sprintf(buf, "%s\n", state);
}
static DEVICE_ATTR_RO(removable);
static ssize_t ltm_capable_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@ -825,7 +802,6 @@ static struct attribute *dev_attrs[] = {
&dev_attr_avoid_reset_quirk.attr,
&dev_attr_authorized.attr,
&dev_attr_remove.attr,
&dev_attr_removable.attr,
&dev_attr_ltm_capable.attr,
#ifdef CONFIG_OF
&dev_attr_devspec.attr,

37
include/linux/device.h
View file

@ -348,6 +348,22 @@ enum dl_dev_state {
DL_DEV_UNBINDING,
};
/**
* enum device_removable - Whether the device is removable. The criteria for a
* device to be classified as removable is determined by its subsystem or bus.
* @DEVICE_REMOVABLE_NOT_SUPPORTED: This attribute is not supported for this
* device (default).
* @DEVICE_REMOVABLE_UNKNOWN: Device location is Unknown.
* @DEVICE_FIXED: Device is not removable by the user.
* @DEVICE_REMOVABLE: Device is removable by the user.
*/
enum device_removable {
DEVICE_REMOVABLE_NOT_SUPPORTED = 0, /* must be 0 */
DEVICE_REMOVABLE_UNKNOWN,
DEVICE_FIXED,
DEVICE_REMOVABLE,
};
/**
* struct dev_links_info - Device data related to device links.
* @suppliers: List of links to supplier devices.
@ -435,6 +451,9 @@ 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
* @removable: Whether the device can be removed from the system. This
* should be set by the subsystem / bus driver that discovered
* the device.
*
* @offline_disabled: If set, the device is permanently online.
* @offline: Set after successful invocation of bus type's .offline().
@ -546,6 +565,8 @@ struct device {
struct iommu_group *iommu_group;
struct dev_iommu *iommu;
enum device_removable removable;
bool offline_disabled:1;
bool offline:1;
bool of_node_reused:1;
@ -781,6 +802,22 @@ static inline bool dev_has_sync_state(struct device *dev)
return false;
}
static inline void dev_set_removable(struct device *dev,
enum device_removable removable)
{
dev->removable = removable;
}
static inline bool dev_is_removable(struct device *dev)
{
return dev->removable == DEVICE_REMOVABLE;
}
static inline bool dev_removable_is_valid(struct device *dev)
{
return dev->removable != DEVICE_REMOVABLE_NOT_SUPPORTED;
}
/*
* High level routines for use by the bus drivers
*/

7
include/linux/usb.h
View file

@ -478,12 +478,6 @@ struct usb_dev_state;
struct usb_tt;
enum usb_device_removable {
USB_DEVICE_REMOVABLE_UNKNOWN = 0,
USB_DEVICE_REMOVABLE,
USB_DEVICE_FIXED,
};
enum usb_port_connect_type {
USB_PORT_CONNECT_TYPE_UNKNOWN = 0,
USB_PORT_CONNECT_TYPE_HOT_PLUG,
@ -710,7 +704,6 @@ struct usb_device {
#endif
struct wusb_dev *wusb_dev;
int slot_id;
enum usb_device_removable removable;
struct usb2_lpm_parameters l1_params;
struct usb3_lpm_parameters u1_params;
struct usb3_lpm_parameters u2_params;