tty: use u8 for flags

This makes all those 'char's an explicit 'u8'. This is part of the
continuing unification of chars and flags to be consistent u8.

This approaches tty_port_default_receive_buf().

Note that we do not change signedness as we compile with
-funsigned-char.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: William Hubbs <w.d.hubbs@gmail.com>
Cc: Chris Brannon <chris@the-brannons.com>
Cc: Kirk Reiser <kirk@reisers.ca>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Max Staudt <max@enpas.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Cc: Andreas Koensgen <ajk@comnets.uni-bremen.de>
Cc: Jeremy Kerr <jk@codeconstruct.com.au>
Cc: Matt Johnston <matt@codeconstruct.com.au>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230810091510.13006-18-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: use u8 for chars

This makes all those 'unsigned char's an explicit 'u8'. This is part of
the continuing unification of chars and flags to be consistent u8.

This approaches tty_port_default_receive_buf(). Flags to be next.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: William Hubbs <w.d.hubbs@gmail.com>
Cc: Chris Brannon <chris@the-brannons.com>
Cc: Kirk Reiser <kirk@reisers.ca>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Max Staudt <max@enpas.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Cc: Andreas Koensgen <ajk@comnets.uni-bremen.de>
Cc: Jeremy Kerr <jk@codeconstruct.com.au>
Cc: Matt Johnston <matt@codeconstruct.com.au>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230810091510.13006-17-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: make tty_ldisc_ops::*buf*() hooks operate on size_t

Count passed to tty_ldisc_ops::receive_buf*(), ::lookahead_buf(), and
returned from ::receive_buf2() is expected to be size_t. So set it to
size_t to unify with the rest of the code.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: William Hubbs <w.d.hubbs@gmail.com>
Cc: Chris Brannon <chris@the-brannons.com>
Cc: Kirk Reiser <kirk@reisers.ca>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Max Staudt <max@enpas.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Cc: Andreas Koensgen <ajk@comnets.uni-bremen.de>
Cc: Jeremy Kerr <jk@codeconstruct.com.au>
Cc: Matt Johnston <matt@codeconstruct.com.au>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230810091510.13006-16-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: can327, move overflow test inside can327_ldisc_rx()'s loop

The 'count' is going to be unsigned and the 'count >= 0' test would be
always true then. Move the condition to the loop where this is easier to
check.

It looks as is easier to follow after all too.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Max Staudt <max@enpas.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-can@vger.kernel.org
Link: https://lore.kernel.org/r/20230810091510.13006-15-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: can327: unify error paths in can327_ldisc_rx()

Create a label with can327_uart_side_failure() and spin unlock. And jump
there from all three fail paths.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Max Staudt <max@enpas.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-can@vger.kernel.org
Link: https://lore.kernel.org/r/20230810091510.13006-14-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

can: can327: remove casts from tty->disc_data

tty->disc_data is 'void *', so there is no need to cast from that.
Therefore remove the casts and assign the pointer directly.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Cc: Max Staudt <max@enpas.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Cc: linux-can@vger.kernel.org
Cc: netdev@vger.kernel.org
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Max Staudt <max@enpas.org>
Link: https://lore.kernel.org/r/20230801062237.2687-2-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

can: can327: flush TX_work on ldisc .close()

Additionally, remove it from .ndo_stop().

This ensures that the worker is not called after being freed, and that
the UART TX queue remains active to send final commands when the
netdev is stopped.

Thanks to Jiri Slaby for finding this in slcan:

https://lore.kernel.org/linux-can/20221201073426.17328-1-jirislaby@kernel.org/

A variant of this patch for slcan, with the flush in .ndo_stop() still
present, has been tested successfully on physical hardware:

https://bugzilla.suse.com/show_bug.cgi?id=1205597

Fixes: 43da2f07622f ("can: can327: CAN/ldisc driver for ELM327 based OBD-II adapters")
Cc: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Max Staudt <max@enpas.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-can@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Max Staudt <max@enpas.org>
Link: https://lore.kernel.org/all/20221202160148.282564-1-max@enpas.org
Cc: stable@vger.kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: can327: can327_feed_frame_to_netdev(): fix potential skb leak when netdev is down

In can327_feed_frame_to_netdev(), it did not free the skb when netdev
is down, and all callers of can327_feed_frame_to_netdev() did not free
allocated skb too. That would trigger skb leak.

Fix it by adding kfree_skb() in can327_feed_frame_to_netdev() when netdev
is down. Not tested, just compiled.

Fixes: 43da2f07622f ("can: can327: CAN/ldisc driver for ELM327 based OBD-II adapters")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Link: https://lore.kernel.org/all/20221110061437.411525-1-william.xuanziyang@huawei.com
Reviewed-by: Max Staudt <max@enpas.org>
Cc: stable@vger.kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: dev: fix skb drop check

In commit a6d190f8c767 ("can: skb: drop tx skb if in listen only
mode") the priv->ctrlmode element is read even on virtual CAN
interfaces that do not create the struct can_priv at startup. This
out-of-bounds read may lead to CAN frame drops for virtual CAN
interfaces like vcan and vxcan.

This patch mainly reverts the original commit and adds a new helper
for CAN interface drivers that provide the required information in
struct can_priv.

Fixes: a6d190f8c767 ("can: skb: drop tx skb if in listen only mode")
Reported-by: Dariusz Stojaczyk <Dariusz.Stojaczyk@opensynergy.com>
Cc: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Cc: Max Staudt <max@enpas.org>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20221102095431.36831-1-socketcan@hartkopp.net
Cc: stable@vger.kernel.org # 6.0.x
[mkl: patch pch_can, too]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: can327: fix a broken link to Documentation

Since commit 482a4360c56a ("docs: networking: convert netdevices.txt to
ReST"), Documentation/networking/netdevices.txt has been replaced by
Documentation/networking/netdevices.rst.

Update the comment accordingly to avoid a 'make htmldocs' warning.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/all/6a54aff884ea4f84b661527d75aabd6632140715.1659249135.git.christophe.jaillet@wanadoo.fr
Fixes: 43da2f07622f ("can: can327: CAN/ldisc driver for ELM327 based OBD-II adapters")
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: tree-wide: advertise software timestamping capabilities

Currently, some CAN drivers support hardware timestamping, some do
not. But userland has no method to query which features are supported
(aside maybe of getting RX messages and observe whether or not
hardware timestamps stay at zero).

The canonical way for a network driver to advertised what kind of
timestamping it supports is to implement ethtool_ops::get_ts_info().

This patch only targets the CAN drivers which *do not* support
hardware timestamping. For each of those CAN drivers, implement the
get_ts_info() using the generic ethtool_op_get_ts_info().

This way, userland can do:

| $ ethtool --show-time-stamping canX

to confirm the device timestamping capacities.

N.B. the drivers which support hardware timestamping will be migrated
in separate patches.

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20220727101641.198847-6-mailhol.vincent@wanadoo.fr
[mkl: mscan: add missing mscan_ethtool_ops]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: can327: add software tx timestamps

TX timestamps were added to the can_put_echo_skb() function of can_dev
modules in [1]. However, can327 does not rely on that function and as
such does not offer TX timestamping.

Add a call to skb_tx_timestamp() in the can327_netdev_start_xmit()
function so that the module now supports TX software timestamps.

[1] commit 741b91f1b0ea ("can: dev: can_put_echo_skb(): add software
tx timestamps")
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=741b91f1b0ea34f00f6a7d4539b767c409291fcf

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20220727101641.198847-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: can327: use KBUILD_MODNAME instead of hard coded names

The driver uses the string "can327" to populate
tty_ldisc_ops::name. KBUILD_MODNAME also evaluates to "can327". Use
KBUILD_MODNAME and get rid on the hardcoded string names.

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20220726082707.58758-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: can327: CAN/ldisc driver for ELM327 based OBD-II adapters

This is the can327 driver. It does a surprisingly good job at turning
ELM327 based OBD-II interfaces into cheap CAN interfaces for simple
homebrew projects.

Please see the included documentation for details and limitations:
Documentation/networking/device_drivers/can/can327.rst

Link: https://lore.kernel.org/all/20220618195031.10975-1-max@enpas.org
Signed-off-by: Max Staudt <max@enpas.org>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
[mkl: minor coding style improvements]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>