mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-05-14 02:59:19 -04:00
Code Issues Packages Projects Releases Wiki Activity

USB: UDC core: Add udc_async_callbacks gadget op

Browse Source 
The Gadget API has a theoretical race when a gadget driver is unbound.
Although the pull-up is turned off before the driver's ->unbind
callback runs, if the USB cable were to be unplugged at just the wrong
moment there would be nothing to prevent the UDC driver from invoking
the ->disconnect callback after the unbind has finished.  In theory,
other asynchronous callbacks could also happen during the time before
the UDC driver's udc_stop routine is called, and the gadget driver
would not be prepared to handle any of them.

We need a way to tell UDC drivers to stop issuing asynchronous (that is,
->suspend, ->resume, ->disconnect, ->reset, or ->setup) callbacks at
some point after the pull-up has been turned off and before the
->unbind callback runs.  This patch adds a new ->udc_async_callbacks
callback to the usb_gadget_ops structure for precisely this purpose,
and it adds the corresponding support to the UDC core.

Later patches in this series add support for udc_async_callbacks to
several UDC drivers.

Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20210520202144.GC1216852@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern
2021-05-20 16:21:44 -04:00
committed by Greg Kroah-Hartman
parent ab1150e957
commit 7dc0c55e9f
2 changed files with 50 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/usb/gadget.h
View File

@@ -325,6 +325,7 @@ struct usb_gadget_ops {
void (*udc_set_speed)(struct usb_gadget *, enum usb_device_speed);
void (*udc_set_ssp_rate)(struct usb_gadget *gadget,
enum usb_ssp_rate rate);
void (*udc_async_callbacks)(struct usb_gadget *gadget, bool enable);
struct usb_ep *(*match_ep)(struct usb_gadget *,
struct usb_endpoint_descriptor *,
struct usb_ss_ep_comp_descriptor *);