linux.git/drivers/usb/gadget/function/u_serial.c, branch v5.13

usb: gadget: u_serial: Remove old tasklet comments

2021-01-19T12:30:52+00:00

Update old comments as of 8b4c62aef6f (usb: gadget: u_serial: process RX
in workqueue instead of tasklet).

Acked-by: Felipe Balbi 
Signed-off-by: Davidlohr Bueso 
Link: https://lore.kernel.org/r/20210119001321.127750-1-dave@stgolabs.net
Signed-off-by: Greg Kroah-Hartman

usb: gadget: u_serial: use %*ph to print small buffer

2021-01-04T15:39:11+00:00

Use %*ph format to print small buffer as hex string.

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20201228200203.58525-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

usb: gadget: u_serial: clear suspended flag when disconnecting

2020-10-02T06:57:41+00:00

The commit aba3a8d01d62 ("usb: gadget: u_serial: add suspend resume
callbacks") set/cleared the suspended flag in USB bus suspend/resume
only. But, when a USB cable is disconnected in the suspend, since some
controllers will not detect USB bus resume, the suspended flag is not
cleared. After that, user cannot send any data. To fix the issue,
clears the suspended flag in the gserial_disconnect().

Fixes: aba3a8d01d62 ("usb: gadget: u_serial: add suspend resume callbacks")
Signed-off-by: Yoshihiro Shimoda 
Tested-by: Linh Phung 
Tested-by: Tam Nguyen 
Signed-off-by: Felipe Balbi

usb: gadget: Use fallthrough pseudo-keyword

2020-07-10T06:55:18+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva 
Link: https://lore.kernel.org/r/20200707171500.GA13620@embeddedor
Signed-off-by: Greg Kroah-Hartman

usb: gadget: function: u_serial: Repair misdocumented function argument

2020-07-09T14:47:00+00:00

Looks as though this has been an issue since the driver's
inception back in 2014.

Fixes the following W=1 kernel build warning(s):

 drivers/usb/gadget/function/u_serial.c:538: warning: Function parameter or member 'port' not described in 'gs_start_io'
 drivers/usb/gadget/function/u_serial.c:538: warning: Excess function parameter 'dev' description in 'gs_start_io'

Cc: Felipe Balbi 
Cc: "Michał Mirosław" 
Cc: Al Borchers 
Cc: Peter Berger 
Signed-off-by: Lee Jones 
Link: https://lore.kernel.org/r/20200703174148.2749969-27-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman

usb: gadget: u_serial: add suspend resume callbacks

2020-05-25T08:09:39+00:00

Add suspend resume callbacks to handle the case seen when the bus is
suspended by the HOST, and the device opens the port (cat /dev/ttyGS0).

Gadget controller (like DWC2) doesn't accept usb requests to be queued in
this case (when in L2 state), from the gs_open() call. Error log is printed
- configfs-gadget gadget: acm ttyGS0 can't notify serial state, -11
If the HOST resumes (opens) the bus, the port still isn't functional.

Use suspend/resume callbacks to monitor the gadget suspended state by using
'suspended' flag. In case the port gets opened (cat /dev/ttyGS0), the I/O
stream will be delayed until the bus gets resumed by the HOST.

Signed-off-by: Fabrice Gasnier 
Signed-off-by: Felipe Balbi

usb: gadget: serial: fix Tx stall after buffer overflow

2020-02-11T06:45:45+00:00

Symptom: application opens /dev/ttyGS0 and starts sending (writing) to
it while either USB cable is not connected, or nobody listens on the
other side of the cable. If driver circular buffer overflows before
connection is established, no data will be written to the USB layer
until/unless /dev/ttyGS0 is closed and re-opened again by the
application (the latter besides having no means of being notified about
the event of establishing of the connection.)

Fix: on open and/or connect, kick Tx to flush circular buffer data to
USB layer.

Signed-off-by: Sergey Organov 
Reviewed-by: Michał Mirosław 
Signed-off-by: Felipe Balbi

usb: gadget: u_serial: use mutex for serialising open()s

2019-10-22T07:27:20+00:00

Remove home-made waiting mechanism from gs_open() and rely on
portmaster's mutex to do the job.

Note: This releases thread waiting on close() when another thread
open()s simultaneously.

Signed-off-by: Michał Mirosław 
Signed-off-by: Felipe Balbi

usb: gadget: u_serial: diagnose missed console messages

2019-10-22T07:27:17+00:00

Insert markers in console stream marking places where data
is missing. This makes the hole in the data stand out clearly
instead of glueing together unrelated messages.

Example output as seen from USB host side:

[    0.064078] pinctrl core: registered pin 16 (UART3_RTS_N PC0) on 70000868.pinmux
[    0.064130] pinctrl
[missed 114987 bytes]
[    4.302299] udevd[134]: starting version 3.2.5
[    4.306845] random: udevd: uninitialized urandom read (16 bytes read)

Signed-off-by: Michał Mirosław 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Felipe Balbi

usb: gadget: u_serial: allow more console gadget ports

2019-10-22T07:27:12+00:00

Allow configuring more than one console using USB serial or ACM gadget.

By default, only first (ttyGS0) is a console, but this may be changed
using function's new "console" attribute.

Signed-off-by: Michał Mirosław 
Signed-off-by: Felipe Balbi