linux.git/drivers/usb/gadget/function/f_hid.c, branch v6.13

usb: gadget: function: move u_f.h to include/linux/usb/func_utils.h

2024-09-03T07:57:08+00:00

We move the func_utils.h header to include/linux/usb to be
able to compile function drivers outside of the
drivers/usb/gadget/function directory.

Signed-off-by: Michael Grzeschik 
Link: https://lore.kernel.org/r/20240116-ml-topic-u9p-v12-1-9a27de5160e0@pengutronix.de
Signed-off-by: Greg Kroah-Hartman

USB: gadget: f_hid: Add GET_REPORT via userspace IOCTL

2024-08-22T09:25:59+00:00

While supporting GET_REPORT is a mandatory request per the HID
specification the current implementation of the GET_REPORT request responds
to the USB Host with an empty reply of the request length. However, some
USB Hosts will request the contents of feature reports via the GET_REPORT
request. In addition, some proprietary HID 'protocols' will expect
different data, for the same report ID, to be to become available in the
feature report by sending a preceding SET_REPORT to the USB Device that
defines what data is to be presented when that feature report is
subsequently retrieved via GET_REPORT (with a very fast < 5ms turn around
between the SET_REPORT and the GET_REPORT).

There are two other patch sets already submitted for adding GET_REPORT
support. The first [1] allows for pre-priming a list of reports via IOCTLs
which then allows the USB Host to perform the request, with no further
userspace interaction possible during the GET_REPORT request. And another
[2] which allows for a single report to be setup by userspace via IOCTL,
which will be fetched and returned by the kernel for subsequent GET_REPORT
requests by the USB Host, also with no further userspace interaction
possible.

This patch, while loosely based on both the patch sets, differs by allowing
the option for userspace to respond to each GET_REPORT request by setting
up a poll to notify userspace that a new GET_REPORT request has arrived. To
support this, two extra IOCTLs are supplied. The first of which is used to
retrieve the report ID of the GET_REPORT request (in the case of having
non-zero report IDs in the HID descriptor). The second IOCTL allows for
storing report responses in a list for responding to requests.

The report responses are stored in a list (it will be either added if it
does not exist or updated if it exists already). A flag (userspace_req) can
be set to whether subsequent requests notify userspace or not.

Basic operation when a GET_REPORT request arrives from USB Host:

- If the report ID exists in the list and it is set for immediate return
  (i.e. userspace_req == false) then response is sent immediately,
userspace is not notified

- The report ID does not exist, or exists but is set to notify userspace
  (i.e. userspace_req == true) then notify userspace via poll:

	- If userspace responds, and either adds or update the response in
	  the list and respond to the host with the contents

	- If userspace does not respond within the fixed timeout (2500ms)
	  but the report has been set prevously, then send 'old' report
	  contents

	- If userspace does not respond within the fixed timeout (2500ms)
	  and the report does not exist in the list then send an empty
	  report

Note that userspace could 'prime' the report list at any other time.

While this patch allows for flexibility in how the system responds to
requests, and therefore the HID 'protocols' that could be supported, a
drawback is the time it takes to service the requests and therefore the
maximum throughput that would be achievable. The USB HID Specification
v1.11 itself states that GET_REPORT is not intended for periodic data
polling, so this limitation is not severe.

Testing on an iMX8M Nano Ultra Lite with a heavy multi-core CPU loading
showed that userspace can typically respond to the GET_REPORT request
within 1200ms - which is well within the 5000ms most operating systems seem
to allow, and within the 2500ms set by this patch.

[1] https://lore.kernel.org/all/20220805070507.123151-2-sunil@amarulasolutions.com/
[2] https://lore.kernel.org/all/20220726005824.2817646-1-vi@endrift.com/

Signed-off-by: David Sands 
Signed-off-by: Chris Wulff 
Link: https://lore.kernel.org/r/20240817142850.1311460-2-crwulff@gmail.com
Signed-off-by: Greg Kroah-Hartman

usb: gadget: add missing MODULE_DESCRIPTION() macros

2024-06-20T17:18:19+00:00

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/libcomposite.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_acm.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_ss_lb.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/u_serial.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_serial.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_obex.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/u_ether.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_ncm.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_ecm.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_phonet.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_eem.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_ecm_subset.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_rndis.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_mass_storage.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_fs.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_uac1.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_uac1_legacy.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_uac2.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_uvc.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_midi.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_midi2.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_hid.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_printer.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_tcm.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/legacy/g_zero.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/legacy/g_midi.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/legacy/g_dbgp.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson 
Link: https://lore.kernel.org/r/20240605-md-drivers-usb-gadget-v1-1-29847a46aad3@quicinc.com
Signed-off-by: Greg Kroah-Hartman

usb: gadget: function: Remove usage of the deprecated ida_simple_xx() API

2024-04-18T14:46:56+00:00

ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().

Note that the upper limit of ida_simple_get() is exclusive, but the one of
ida_alloc_max() is inclusive. So a -1 has been added when needed.

Signed-off-by: Christophe JAILLET 
Link: https://lore.kernel.org/r/7cd361e2b377a5373968fa7deee4169229992a1e.1713107386.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_hid: fix report descriptor allocation

2023-12-07T01:12:05+00:00

The commit 89ff3dfac604 ("usb: gadget: f_hid: fix f_hidg lifetime vs
cdev") has introduced a bug that leads to hid device corruption after
the replug operation.
Reverse device managed memory allocation for the report descriptor
to fix the issue.

Tested:
This change was tested on the AMD EthanolX CRB server with the BMC
based on the OpenBMC distribution. The BMC provides KVM functionality
via the USB gadget device:
- before: KVM page refresh results in a broken USB device,
- after: KVM page refresh works without any issues.

Fixes: 89ff3dfac604 ("usb: gadget: f_hid: fix f_hidg lifetime vs cdev")
Cc: stable@vger.kernel.org
Signed-off-by: Konstantin Aladyshev 
Link: https://lore.kernel.org/r/20231206080744.253-2-aladyshev22@gmail.com
Signed-off-by: Greg Kroah-Hartman

USB: gadget: f_hid: make hidg_class a static const structure

2023-06-20T14:20:48+00:00

Now that the driver core allows for struct class to be in read-only
memory, move the hidg_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at load time.

Suggested-by: Greg Kroah-Hartman 
Signed-off-by: Ivan Orlov 
Link: https://lore.kernel.org/r/20230620094412.508580-11-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: class: remove module * from class_create()

2023-03-17T14:16:33+00:00

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
something.  So just remove it and fix up all callers of the function in
the kernel tree at the same time.

Cc: "Rafael J. Wysocki" 
Acked-by: Benjamin Tissoires 
Link: https://lore.kernel.org/r/20230313181843.1207845-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_hid: tidy error handling in hidg_alloc

2022-11-29T07:56:09+00:00

Unify error handling at the end of the function, reducing the risk of
missing something on one of the error paths.

Moving the increment of opts->refcnt later means there is no need to
decrement it on the error path and is safe as this is guarded by
opts->lock which is held for this entire section.

Tested-by: Lee Jones 
Reviewed-by: Andrzej Pietrasiewicz 
Reviewed-by: Lee Jones 
Signed-off-by: John Keeping 
Link: https://lore.kernel.org/r/20221122123523.3068034-4-john@metanate.com
Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_hid: fix refcount leak on error path

2022-11-29T07:56:09+00:00

When failing to allocate report_desc, opts->refcnt has already been
incremented so it needs to be decremented to avoid leaving the options
structure permanently locked.

Fixes: 21a9476a7ba8 ("usb: gadget: hid: add configfs support")
Tested-by: Lee Jones 
Reviewed-by: Andrzej Pietrasiewicz 
Reviewed-by: Lee Jones 
Signed-off-by: John Keeping 
Link: https://lore.kernel.org/r/20221122123523.3068034-3-john@metanate.com
Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_hid: fix f_hidg lifetime vs cdev

2022-11-29T07:56:09+00:00

The embedded struct cdev does not have its lifetime correctly tied to
the enclosing struct f_hidg, so there is a use-after-free if /dev/hidgN
is held open while the gadget is deleted.

This can readily be replicated with libusbgx's example programs (for
conciseness - operating directly via configfs is equivalent):

	gadget-hid
	exec 3<> /dev/hidg0
	gadget-vid-pid-remove
	exec 3<&-

Pull the existing device up in to struct f_hidg and make use of the
cdev_device_{add,del}() helpers.  This changes the lifetime of the
device object to match struct f_hidg, but note that it is still added
and deleted at the same time.

Fixes: 71adf1189469 ("USB: gadget: add HID gadget driver")
Tested-by: Lee Jones 
Reviewed-by: Andrzej Pietrasiewicz 
Reviewed-by: Lee Jones 
Signed-off-by: John Keeping 
Link: https://lore.kernel.org/r/20221122123523.3068034-2-john@metanate.com
Signed-off-by: Greg Kroah-Hartman