Some CH340 devices appear unable to change the initial LCR settings, so
set a sane 8N1 default during probe to enable basic support for such
devices.

Also drop a redundant LCR read during device initialisation.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Rename the line-control-register variable in set_termios to "lcr" and
use u8 type to match the shadow register.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Rename the shadow modem-status register currently named "line_status" to
the less confusing "msr".

Also rename the helper function used to parse the interrupt data.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Rename the shadow modem-control register currently named "line_control"
to the less confusing "mcr".
Signed-off-by: NJohan Hovold <johan@kernel.org>

Clean up the control-transfer debug messages by dropping redundant
information and unnecessary casts.
Signed-off-by: NJohan Hovold <johan@kernel.org>

The modem-status register was read as part of device configuration at
port_probe and then again at open (and reset-resume). During open (and
reset-resume) the MSR was read before submitting the interrupt URB,
something which could lead to an MSR-change going unnoticed when it
races with open (reset-resume).

Fix this by dropping the redundant reconfiguration of the port at every
open, and only read the MSR after the interrupt URB has been submitted.

Fixes: 664d5df9 ("USB: usb-serial ch341: support for DTR/RTS/CTS")
Signed-off-by: NJohan Hovold <johan@kernel.org>

A short control transfer would currently fail to be detected, something
which could lead to stale buffer data being used as valid input.

Check for short transfers, and make sure to log any transfer errors.

Note that this also avoids leaking heap data to user space (TIOCMGET)
and the remote device (break control).

Fixes: 6ce76104 ("USB: Driver for CH341 USB-serial adaptor")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Revert to using direct register writes to set the divisor and
line-control registers.

A recent change switched to using the init vendor command to update
these registers, something which also enabled support for CH341A
devices. It turns out that simply setting bit 7 in the divisor register
is sufficient to support CH341A and specifically prevent data from being
buffered until a full endpoint-size packet (32 bytes) has been received.

Using the init command also had the side-effect of temporarily
deasserting the DTR/RTS signals on every termios change (including
initialisation on open) something which for example could cause problems
in setups where DTR is used to trigger a reset.

Fixes: 4e46c410 ("USB: serial: ch341: reinitialize chip on
reconfiguration")
Signed-off-by: NJohan Hovold <johan@kernel.org>

A recent change added support for modifying the default line-control
settings, but did not make sure that the modified settings were used as
part of reconfiguration after a device has been reset during resume.

This caused a port that was open before suspend to be unusable until
being closed and reopened.

Fixes: ba781bdf ("USB: serial: ch341: add support for parity, frame
length, stop bits")
Signed-off-by: NJohan Hovold <johan@kernel.org>

Fix reset-resume handling which failed to resubmit the read and
interrupt URBs, thereby leaving a port that was open before suspend in a
broken state until closed and reopened.

Fixes: 1ded7ea4 ("USB: ch341 serial: fix port number changed after
resume")
Fixes: 2bfd1c96 ("USB: serial: ch341: remove reset_resume callback")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Make sure to stop the interrupt URB before returning on errors during
open.

Fixes: 664d5df9 ("USB: usb-serial ch341: support for DTR/RTS/CTS")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

The modem-control signals are managed by the tty-layer during open and
should not be asserted prematurely when set_termios is called from
driver open.

Also make sure that the signals are asserted only when changing speed
from B0.

Fixes: 664d5df9 ("USB: usb-serial ch341: support for DTR/RTS/CTS")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

The private baud_rate variable is used to configure the port at open and
reset-resume and must never be set to (and left at) zero or reset-resume
and all further open attempts will fail.

Fixes: aa91def4 ("USB: ch341: set tty baud speed according to tty
struct")
Fixes: 664d5df9 ("USB: usb-serial ch341: support for DTR/RTS/CTS")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

DTR and RTS will be asserted by the tty-layer when the port is opened
and deasserted on close (if HUPCL is set). Make sure the initial state
is not-asserted before the port is first opened as well.

Fixes: 664d5df9 ("USB: usb-serial ch341: support for DTR/RTS/CTS")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Will probably be helpful if there are any more compatibility issues.
Signed-off-by: NAidan Thornton <makosoft@gmail.com>
Reviewed-by: NGrigori Goronzy <greg@chown.ath.cx>
Signed-off-by: NJohan Hovold <johan@kernel.org>

With the new reinitialization method, configuring parity, different
frame lengths and different stop bit settings should work as expected
on both CH340G and CH341A. Tested on a loopback-connected CH340G
with a logic analyzer in a number of different configurations.

Based on a patch by Grigori Goronzy
Signed-off-by: NAidan Thornton <makosoft@gmail.com>
Reviewed-by: NGrigori Goronzy <greg@chown.ath.cx>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Changing the LCR register after initialization does not seem to be reliable
on all chips (particularly not on CH341A). Restructure initialization and
configuration to always reinit the chip on configuration changes instead and
pass the LCR register value directly to the initialization command.

(Note that baud rates above 500kbaud are incorrect, but they're incorrect in
the same way both before and after this patch at least on the CH340G. Fixing
this isn't a priority as higher baud rates don't seem that reliable anyway.)

Cleaned-up version of a patch by Grigori Goronzy
Signed-off-by: NAidan Thornton <makosoft@gmail.com>
Reviewed-by: NGrigori Goronzy <greg@chown.ath.cx>
Signed-off-by: NJohan Hovold <johan@kernel.org>

No functional changes, this just gives names to some registers and USB
requests based on Grigori Goronzy's work and WinChipTech's Linux driver
(which reassuringly agree), then uses them in place of magic numbers.
This also renames the misnamed BREAK2 register (actually UART config)
Signed-off-by: NAidan Thornton <makosoft@gmail.com>
Reviewed-by: NGrigori Goronzy <greg@chown.ath.cx>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Move constants to the right of binary operators where it increases
readability.

Generated by: scripts/coccinelle/misc/compare_const_fl.cocci
Signed-off-by: NMathieu OTHACEHE <m.othacehe@gmail.com>
[johan: drop some chunks and fix others, amend commit message ]
Signed-off-by: NJohan Hovold <johan@kernel.org>

The ch341_set_baudrate() function initialize the device baud speed
according to the value on priv->baud_rate. By default the ch341_open() set
it to a hardcoded value (DEFAULT_BAUD_RATE 9600). Unfortunately, the
tty_struct is not initialized with the same default value. (usually 56700)

This means that the tty_struct and the device baud rate generator are not
synchronized after opening the port.

Fixup is done by calling ch341_set_termios() if tty exist.
Remove unnecessary variable priv->baud_rate setup as it's already done by
ch341_port_probe().
Remove unnecessary call to ch341_set_{handshake,baudrate}() in
ch341_open() as there already called in ch341_configure() and
ch341_set_termios()
Signed-off-by: NNicolas PLANEL <nicolas.planel@enovance.com>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Remove redundant call to ch341_close from error path when submission of
the interrupt urb fails in open.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Add missing newlines to dev_<level> messages.

Also make some messages less verbose where appropriate.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <greg@kroah.com>

None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>.  Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Clean up interrupt completion handler somewhat.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the generic TIOCMIWAIT implementation which does not suffer
from the races involved when using the deprecated sleep_on functions.
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Only wake up MSR wait queue on actual modem-status changes.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure the TIOCMIWAIT mask is always honoured.

The CH341 interrupt status has a multiple-status changed flag which
indicates that multiple status changes has occurred since last interrupt
event. Unfortunately, if the final status is the same, there appears to
be no way to determine which signal(s) has changed (an even number of
times).

This means that the multiple-status flag should not be used in
TIOCMIWAIT as it leads to the signal mask argument being ignored (e.g.
TIOCMIWAIT could return if DSR changes twice, even though the user only
cares about carrier changes).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Clean up line-status handling.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Refactor line-status handling.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove redundant error messages on allocation failures, which have
already been logged.

Cc: Joe Perches <joe@perches.com>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use tty-port modem-status-change wait queue on which processes are woken
up at hangup and disconnect.

Currently a process waiting on modem-status changes will not be woken on
device disconnect as wake up was only done in dtr_rts which isn't
guaranteed to be called (e.g. if HUPCL is not set).

Also remove the redundant wake-up call from dtr_rts.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace custom ioctl operation with tiocmiwait.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the port wait queue and make sure to check the serial disconnected
flag before accessing private port data after waking up.

This is is needed as the private port data (including the wait queue
itself) can be gone when waking up after a disconnect.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix port-data memory leak by moving port data allocation to port_probe
and actually implementing deallocation.

Note that this driver has never even bothered to try to deallocate it's
port data...

Compile-only tested.

Cc: <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that all usb-serial modules are only using dev_dbg()
the debug module parameter does not do anything at all, so
remove it to reduce any confusion if someone were to try to
use it.

CC: Johan Hovold <jhovold@gmail.com>
CC: Alan Stern <stern@rowland.harvard.edu>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We should use dev_dbg() for usb_serial_debug_data() like all of the rest
of the usb-serial drivers use, so remove the debug parameter as it's not
needed.
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

dbg() was a very old USB-serial-specific macro.
This patch removes it from being used in the
driver and uses dev_dbg() instead.

CC: Johan Hovold <jhovold@gmail.com>
CC: Alan Stern <stern@rowland.harvard.edu>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

I hooked up the wrong callback in my previous patch, this should fix it.
Reported-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: Johan Hovold <jhovold@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A few patches ago, I removed the reset_resume callback, changing it to
resume instead.  Now that the usb-serial core supports reset_resume, put
this driver callback back as well, so it should work identically to how
it was originally.

Now if this function really is doing what it should be doing, well,
that's a different story, but we are at least doing the identical thing
that we were before...

Cc: Johan Hovold <jhovold@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reworks the usb_serial_register_drivers() and
usb_serial_deregister_drivers() to not need a pointer to a struct
usb_driver anymore.  The usb_driver structure is now created dynamically
and registered and unregistered as needed.

This saves lines of code in each usb-serial driver.  All in-kernel users
of these functions were also fixed up at this time.  The pl2303 driver
was tested that everything worked properly.

Thanks for the idea to do this from Alan Stern.

Cc: Adhir Ramjiawan <adhirramjiawan0@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Al Borchers <alborchers@steinerpoint.com>
Cc: Aleksey Babahin <tamerlan311@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Worsley <amworsley@gmail.com>
Cc: Bart Hartgers <bart.hartgers@gmail.com>
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Donald Lee <donald@asix.com.tw>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Gary Brubaker <xavyer@ix.netcom.com>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Johan Hovold <jhovold@gmail.com>
Cc: Julia Lawall <julia@diku.dk>
Cc: Kautuk Consul <consul.kautuk@gmail.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Lonnie Mendez <dignome@gmail.com>
Cc: Matthias Bruestle and Harald Welte <support@reiner-sct.com>
Cc: Matthias Urlichs <smurf@smurf.noris.de>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Michal Sroczynski <msroczyn@gmail.com>
Cc: "Michał Wróbel" <michal.wrobel@flytronic.pl>
Cc: Oliver Neukum <oliver@neukum.name>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Berger <pberger@brimson.com>
Cc: Preston Fick <preston.fick@silabs.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Rigbert Hamisch <rigbert@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Simon Arlott <simon@fire.lp0.eu>
Cc: Support Department <support@connecttech.com>
Cc: Thomas Tuttle <ttuttle@chromium.org>
Cc: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Cc: Wang YanQing <Udknight@gmail.com>
Cc: William Greathouse <wgreathouse@smva.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>