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 <lee@kernel.org>
Reviewed-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Reviewed-by: Lee Jones <lee@kernel.org>
Signed-off-by: John Keeping <john@metanate.com>
Link: https://lore.kernel.org/r/20221122123523.3068034-4-john@metanate.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 <lee@kernel.org>
Reviewed-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Reviewed-by: Lee Jones <lee@kernel.org>
Signed-off-by: John Keeping <john@metanate.com>
Link: https://lore.kernel.org/r/20221122123523.3068034-3-john@metanate.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 <lee@kernel.org>
Reviewed-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Reviewed-by: Lee Jones <lee@kernel.org>
Signed-off-by: John Keeping <john@metanate.com>
Link: https://lore.kernel.org/r/20221122123523.3068034-2-john@metanate.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

f_hid provides the OUT Endpoint as only way for receiving reports
from the host. SETUP/SET_REPORT method is not supported, and this causes
a number of compatibility problems with various host drivers, especially
in the case of keyboard emulation using f_hid.

  - Some hosts do not support the OUT Endpoint and ignore it,
    so it becomes impossible for the gadget to receive a report
    from the host. In the case of a keyboard, the gadget loses
    the ability to receive the status of the LEDs.

  - Some BIOSes/UEFIs can't work with HID devices with the OUT Endpoint
    at all. This may be due to their bugs or incomplete implementation
    of the HID standard.
    For example, absolutely all Apple UEFIs can't handle the OUT Endpoint
    if it goes after IN Endpoint in the descriptor and require the reverse
    order (OUT, IN) which is a violation of the standard.
    Other hosts either do not initialize gadgets with a descriptor
    containing the OUT Endpoint completely (like some HP and DELL BIOSes
    and embedded firmwares like on KVM switches), or initialize them,
    but will not poll the IN Endpoint.

This patch adds configfs option no_out_endpoint=1 to disable
the OUT Endpoint and allows f_hid to receive reports from the host
via SETUP/SET_REPORT.

Previously, there was such a feature in f_hid, but it was replaced
by the OUT Endpoint [1] in the commit 99c515005857 ("usb: gadget: hidg:
register OUT INT endpoint for SET_REPORT"). So this patch actually
returns the removed functionality while making it optional.
For backward compatibility reasons, the OUT Endpoint mode remains
the default behaviour.

  - The OUT Endpoint mode provides the report queue and reduces
    USB overhead (eliminating SETUP routine) on transmitting a report
    from the host.

  - If the SETUP/SET_REPORT mode is used, there is no report queue,
    so the userspace will only read last report. For classic HID devices
    like keyboards this is not a problem, since it's intended to transmit
    the status of the LEDs and only the last report is important.
    This mode provides better compatibility with strange and buggy
    host drivers.

Both modes passed USBCV tests. Checking with the USB protocol analyzer
also confirmed that everything is working as it should and the new mode
ensures operability in all of the described cases.

Link: https://www.spinics.net/lists/linux-usb/msg65494.html [1]
Reviewed-by: Maciej Żenczykowski <zenczykowski@gmail.com>
Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Maxim Devaev <mdevaev@gmail.com>
Link: https://lore.kernel.org/r/20210821134004.363217-1-mdevaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

SET_IDLE value must be shifted 8 bits to the right to get duration.
This confirmed by USBCV test.

Fixes: afcff6dc690e ("usb: gadget: f_hid: added GET_IDLE and SET_IDLE handlers")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Maxim Devaev <mdevaev@gmail.com>
Link: https://lore.kernel.org/r/20210727185800.43796-1-mdevaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The USB HID standard declares mandatory support for GET_IDLE and SET_IDLE
requests for Boot Keyboard. Most hosts can handle their absence, but others
like some old/strange UEFIs and BIOSes consider this a critical error
and refuse to work with f_hid.

This primitive implementation of saving and returning idle is sufficient
to meet the requirements of the standard and these devices.

Acked-by: Felipe Balbi <balbi@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Maxim Devaev <mdevaev@gmail.com>
Link: https://lore.kernel.org/r/20210721180351.129450-1-mdevaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Disconnecting and reconnecting the USB cable can lead to crashes
and a variety of kernel log spam.

The problem was found and reproduced on the Raspberry Pi [1]
and the original fix was created in Raspberry's own fork [2].

Link: https://github.com/raspberrypi/linux/issues/3870 [1]
Link: https://github.com/raspberrypi/linux/commit/a6e47d5f4efbd2ea6a0b6565cd2f9b7bb217ded5 [2]
Signed-off-by: Maxim Devaev <mdevaev@gmail.com>
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210723155928.210019-1-mdevaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Running sparse checker it shows warning message about
incorrect endianness used for descriptor initialization:

| f_hid.c:91:43: warning: incorrect type in initializer (different base types)
| f_hid.c:91:43:    expected restricted __le16 [usertype] bcdHID
| f_hid.c:91:43:    got int

Fixing issue with cpu_to_le16() macro, however this is not a real issue
as the value is the same both endians.

Cc: Fabien Chouteau <fabien.chouteau@barco.com>
Cc: Segiy Stetsyuk <serg_stetsuk@ukr.net>
Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
Link: https://lore.kernel.org/r/20210617162755.29676-1-ruslan.bilovol@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We want the usb fixes in here as well, and this resolves some merge
issues with:
	drivers/usb/dwc3/debugfs.c
	drivers/usb/dwc3/gadget.c

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This avoids a null pointer dereference in
f_{ecm,eem,hid,loopback,printer,rndis,serial,sourcesink,subset,tcm}
by simply reusing the 5gbps config for 10gbps.

Fixes: eaef50c76057 ("usb: gadget: Update usb_assign_descriptors for SuperSpeedPlus")
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Michael R Sweet <msweet@msweet.org>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Pawel Laszczak <pawell@cadence.com>
Cc: Peter Chen <peter.chen@nxp.com>
Cc: Sudhakar Panneerselvam <sudhakar.panneerselvam@oracle.com>
Cc: Wei Ming Chen <jj251510319013@gmail.com>
Cc: Will McVicker <willmcvicker@google.com>
Cc: Zqiang <qiang.zhang@windriver.com>
Reviewed-By: Lorenzo Colitti <lorenzo@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Link: https://lore.kernel.org/r/20210608044141.3898496-1-zenczykowski@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>