The actual payload length of the CAN Remote Transmission Request (RTR)
frames is always 0, i.e. no payload is transmitted on the wire.
However, those RTR frames still use the DLC to indicate the length of
the requested frame.
As such, net_device_stats::tx_bytes should not be increased when
sending RTR frames.
The function can_get_echo_skb() already returns the correct length,
even for RTR frames (c.f. [1]). However, for historical reasons, the
drivers do not use can_get_echo_skb()'s return value and instead, most
of them store a temporary length (or dlc) in some local structure or
array. Using the return value of can_get_echo_skb() solves the
issue. After doing this, such length/dlc fields become unused and so
this patch does the adequate cleaning when needed.
This patch fixes all the CAN drivers.
Finally, can_get_echo_skb() is decorated with the __must_check
attribute in order to force future drivers to correctly use its return
value (else the compiler would emit a warning).
[1] commit ed3320cec2 ("can: dev: __can_get_echo_skb():
fix real payload length return value for RTR frames")
Link: https://lore.kernel.org/all/20211207121531.42941-6-mailhol.vincent@wanadoo.fr
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: Yasushi SHOJI <yashi@spacecubics.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Stephane Grosjean <s.grosjean@peak-system.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Tested-by: Jimmy Assarsson <extja@kvaser.com> # kvaser
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Acked-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2
Tested-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2
[mkl: add conversion for grcan]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
In order to implement byte queue limits (bql) in CAN drivers, the length of the
CAN frame needs to be passed into the networking stack after queueing and after
transmission completion.
To avoid to calculate this length twice, extend can_get_echo_skb() to return
that value. Convert all users of this function, too.
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/r/20210111141930.693847-14-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
The naming of can_dlc as element of struct can_frame and also as variable
name is misleading as it claims to be a 'data length CODE' but in reality
it always was a plain data length.
With the indroduction of a new 'len' element in struct can_frame we can now
remove can_dlc as name and make clear which of the former uses was a plain
length (-> 'len') or a data length code (-> 'dlc') value.
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201120100444.3199-1-socketcan@hartkopp.net
[mkl: gs_usb: keep struct gs_host_frame::can_dlc as is]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the version 2 of the gnu general public
license as published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 10 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.259525894@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Trivial fix to spelling mistake in module parameter description text
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Prefer the direct use of octal for permissions.
Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace
and some typing.
Miscellanea:
o Whitespace neatening around these conversions.
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While waiting for the TX object to send an RTR, an external message with a
matching id can overwrite the TX data. In this case we must call the rx
routine and then try transmitting the message that was overwritten again.
The queue was being stalled because the RX event did not generate an
interrupt to wake up the queue again and the TX event did not happen
because the TXRQST flag is reset by the chip when new data is received.
According to the CC770 datasheet the id of a message object should not be
changed while the MSGVAL bit is set. This has been fixed by resetting the
MSGVAL bit before modifying the object in the transmit function and setting
it after. It is not enough to set & reset CPUUPD.
It is important to keep the MSGVAL bit reset while the message object is
being modified. Otherwise, during RTR transmission, a frame with matching
id could trigger an rx-interrupt, which would cause a race condition
between the interrupt routine and the transmit function.
Signed-off-by: Andri Yngvason <andri.yngvason@marel.com>
Tested-by: Richard Weinberger <richard@nod.at>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
As Dan Carpenter reported in http://marc.info/?l=linux-can&m=144793696016187
the assignment of the error location in CAN error messages had some bit wise
overlaps. Indeed the value to be assigned in data[3] is no bitfield but defines
a single value which points to a location inside the CAN frame on the wire.
This patch fixes the assignments for the error locations in error messages.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
There is no guarantee that the skb is in the same state after calling
net_receive_skb() or netif_rx(). It might be freed or reused. Not really
harmful as its a read access, except you turn on the proper debugging options
which catch a use after free.
Cc: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
In order to be able to move the stats increment from can_bus_off() into
can_change_state(), the increment had to be moved back into code that was using
can_bus_off() but not can_change_state().
As a side-effect, this patch fixes the following bugs:
* Redundant call to can_bus_off() in c_can.
* Bus-off counted twice in xilinx_can.
Signed-off-by: Andri Yngvason <andri.yngvason@marel.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
CAN interfaces only support MTU values of 16 (CAN 2.0) and 72 (CAN FD).
Setting the MTU to other values is pointless but it does not really hurt.
With the introduction of the CAN FD support in drivers/net/can a new
function to switch the MTU for CAN FD has been introduced.
This patch makes use of this can_change_mtu() function to check for correct
MTU settings also in legacy CAN (2.0) devices.
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This patch marks the bittiming_const pointer as in the struct can_pric as
"const". This allows us to mark the struct can_bittiming_const in the CAN
drivers as "const", too.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Make cc770_interrupt static to fix the following sparse warning:
drivers/net/can/cc770/cc770.c:699:13: warning: symbol
'cc770_interrupt' was not declared. Should it be static?
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
drivers/net/can/cc770/cc770.c included 'linux/can/dev.h' twice,
remove the duplicate.
Signed-off-by: Danny Kukawka <danny.kukawka@bisect.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
On slow systems and high CAN bitrates, the error message
"can_put_echo_skb: BUG! echo_skb is occupied!" did show up because
can_put_echo_skb() was called after starting the transfer.
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
