In commit a6d190f8 ("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: a6d190f8 ("can: skb: drop tx skb if in listen only mode")
Reported-by: NDariusz Stojaczyk <Dariusz.Stojaczyk@opensynergy.com>
Cc: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Cc: Max Staudt <max@enpas.org>
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Acked-by: NVincent 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: NMarc Kleine-Budde <mkl@pengutronix.de>

We tell driver developers to always pass NAPI_POLL_WEIGHT
as the weight to netif_napi_add(). This may be confusing
to newcomers, drop the weight argument, those who really
need to tweak the weight can use netif_napi_add_weight().

Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> # for CAN
Link: https://lore.kernel.org/r/20220927132753.750069-1-kuba@kernel.orgSigned-off-by: NJakub Kicinski <kuba@kernel.org>

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: NVincent 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: NMarc Kleine-Budde <mkl@pengutronix.de>

Add a dedicated flag in uapi/linux/can/error.h to notify the userland
that fields data[6] and data[7] of the CAN error frame were
respectively populated with the tx and rx error counters.

For all driver tree-wide, set up this flags whenever needed.

Link: https://lore.kernel.org/all/20220719143550.3681-12-mailhol.vincent@wanadoo.frSigned-off-by: NVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

In commit 1be37d3b ("can: m_can: fix periph RX path: use
rx-offload to ensure skbs are sent from softirq context") the RX path
for peripheral devices was switched to RX-offload.

Received CAN frames are pushed to RX-offload together with a
timestamp. RX-offload is designed to handle overflows of the timestamp
correctly, if 32 bit timestamps are provided.

The timestamps of m_can core are only 16 bits wide. So this patch
shifts them to full 32 bit before passing them to RX-offload.

Link: https://lore.kernel.org/all/20220612211410.4081390-1-mkl@pengutronix.de
Fixes: 1be37d3b ("can: m_can: fix periph RX path: use rx-offload to ensure skbs are sent from softirq context")
Cc: <stable@vger.kernel.org> # 5.13
Cc: Torin Cooper-Bennun <torin@maxiluxsystems.com>
Reviewed-by: NChandrasekar Ramakrishnan <rcsekar@samsung.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

In commit df06fd67 ("can: m_can: m_can_chip_config(): enable and
configure internal timestamps") the timestamping in the m_can core
should be enabled. In peripheral mode, the RX'ed CAN frames, TX
compete frames and error events are sorted by the timestamp.

The above mentioned commit however forgot to enable the timestamping.
Add the missing bits to enable the timestamp counter to the write of
the Timestamp Counter Configuration register.

Link: https://lore.kernel.org/all/20220612212708.4081756-1-mkl@pengutronix.de
Fixes: df06fd67 ("can: m_can: m_can_chip_config(): enable and configure internal timestamps")
Cc: <stable@vger.kernel.org> # 5.13
Cc: Torin Cooper-Bennun <torin@maxiluxsystems.com>
Reviewed-by: NChandrasekar Ramakrishnan <rcsekar@samsung.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

This patch fixes the typo prescalar -> prescaler.

Link: https://lore.kernel.org/all/20220610112037.3857192-1-mkl@pengutronix.deReviewed-by: NChandrasekar Ramakrishnan <rcsekar@samsung.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Since commit 30f3b421 ("can: mark led trigger as broken") the
CAN specific LED support was disabled and marked as BROKEN. As the
common LED support with CONFIG_LEDS_TRIGGER_NETDEV should do this work
now the code can be removed as preparation for a CAN netdevice Kconfig
rework.

Link: https://lore.kernel.org/all/20220518154527.29046-1-socketcan@hartkopp.netSuggested-by: NVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
[mkl: remove led.h from MAINTAINERS]
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Now when Intel Elkhart Lake uses again common bit timing and there are
no other users for custom bit timing, we can bring back the changes
done by the commit 0ddd83fb ("can: m_can: remove support for
custom bit timing").

This effectively reverts commit ea768b2f ("Revert "can: m_can:
remove support for custom bit timing"") while taking into account
commit ea22ba40 ("can: m_can: make custom bittiming fields const")
and commit 7d4a101c ("can: dev: add sanity check in
can_set_static_ctrlmode()").

Link: https://lore.kernel.org/all/20220512124144.536850-2-jarkko.nikula@linux.intel.comSigned-off-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Defining local versions of NAPI_POLL_WEIGHT with the same values in
the drivers just makes refactoring harder.

Link: https://lore.kernel.org/all/20220429174446.196655-1-kuba@kernel.orgSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

This patch renames the function can_rx_offload_queue_sorted() to
can_rx_offload_queue_timestamp(). This better describes what the
function does, it adds a newly RX'ed skb to the sorted queue by its
timestamp.

Link: https://lore.kernel.org/all/20220417194327.2699059-1-mkl@pengutronix.deSigned-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

can_put_echo_skb() will clone skb then free the skb. Move the
can_put_echo_skb() for the m_can version 3.0.x directly before the
start of the xmit in hardware, similar to the 3.1.x branch.

Fixes: 80646733 ("can: m_can: update to support CAN FD features")
Link: https://lore.kernel.org/all/20220317081305.739554-1-mkl@pengutronix.de
Cc: stable@vger.kernel.org
Reported-by: NHangyu Hua <hbh25y@gmail.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

In order to optimize FIFO access, especially on m_can cores attached
to slow busses like SPI, in patch

| e3938177 ("can: m_can: Disable IRQs on FIFO bus errors")

bulk read/write support has been added to the m_can_fifo_{read,write}
functions.

That change leads to the tcan driver to call
regmap_bulk_{read,write}() with a length of 0 (for CAN frames with 0
data length). regmap treats this as an error:

| tcan4x5x spi1.0 tcan4x5x0: FIFO write returned -22

This patch fixes the problem by not calling the
cdev->ops->{read,write)_fifo() in case of a 0 length read/write.

Fixes: e3938177 ("can: m_can: Disable IRQs on FIFO bus errors")
Link: https://lore.kernel.org/all/20220114155751.2651888-1-mkl@pengutronix.de
Cc: stable@vger.kernel.org
Cc: Matt Kline <matt@bitbashing.io>
Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.com>
Reported-by: NMichael Anochin <anochin@photo-meter.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Previous patch removed can_priv::ctrlmode_static to replace it with
can_get_static_ctrlmode().

A condition sine qua non for this to work is that the controller
static modes should never be set in can_priv::ctrlmode_supported
(c.f. the comment on can_priv::ctrlmode_supported which states that it
is for "options that can be *modified* by netlink"). Also, this
condition is already correctly fulfilled by all existing drivers
which rely on the ctrlmode_static feature.

Nonetheless, we added an extra safeguard in can_set_static_ctrlmode()
to return an error value and to warn the developer who would be
adventurous enough to set to static a given feature that is already
set to supported.

The drivers which rely on the static controller mode are then updated
to check the return value of can_set_static_ctrlmode().

Link: https://lore.kernel.org/all/20211213160226.56219-3-mailhol.vincent@wanadoo.frSigned-off-by: NVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

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::rx_bytes should not be increased for the
RTR frames.

This patch fixes all the CAN drivers.

Link: https://lore.kernel.org/all/20211207121531.42941-5-mailhol.vincent@wanadoo.fr
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.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: Appana Durga Kedareswara rao <appana.durga.rao@xilinx.com>
Cc: Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Jimmy Assarsson <extja@kvaser.com> # kvaser
Signed-off-by: NVincent 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
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The CAN error message frames (i.e. error skb) are an interface
specific to socket CAN. The payload of the CAN error message frames
does not correspond to any actual data sent on the wire. Only an error
flag and a delimiter are transmitted when an error occurs (c.f. ISO
11898-1 section 10.4.4.2 "Error flag").

For this reason, it makes no sense to increment the rx_packets and
rx_bytes fields of struct net_device_stats because no actual payload
were transmitted on the wire.

This patch fixes all the CAN drivers.

Link: https://lore.kernel.org/all/20211207121531.42941-2-mailhol.vincent@wanadoo.fr
CC: Marc Kleine-Budde <mkl@pengutronix.de>
CC: Nicolas Ferre <nicolas.ferre@microchip.com>
CC: Alexandre Belloni <alexandre.belloni@bootlin.com>
CC: Ludovic Desroches <ludovic.desroches@microchip.com>
CC: Chandrasekar Ramakrishnan <rcsekar@samsung.com>
CC: Maxime Ripard <mripard@kernel.org>
CC: Chen-Yu Tsai <wens@csie.org>
CC: Jernej Skrabec <jernej.skrabec@gmail.com>
CC: Appana Durga Kedareswara rao <appana.durga.rao@xilinx.com>
CC: Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
CC: Michal Simek <michal.simek@xilinx.com>
CC: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Jimmy Assarsson <extja@kvaser.com> # kvaser
Signed-off-by: NVincent 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
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The timing limits specified by the Elkhart Lake CPU datasheets do not
match the defaults. Let's reintroduce the support for custom bit timings.

This reverts commit 0ddd83fb.

Link: https://lore.kernel.org/all/00c9e2596b1a548906921a574d4ef7a03c0dace0.1636967198.git.matthias.schiffer@ew.tq-group.comSigned-off-by: NMatthias Schiffer <matthias.schiffer@ew.tq-group.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

In m_can_read_fifo(), if the second call to m_can_fifo_read() fails,
the function jump to the out_fail label and returns without calling
m_can_receive_skb(). This means that the skb previously allocated by
alloc_can_skb() is not freed. In other terms, this is a memory leak.

This patch adds a goto label to destroy the skb if an error occurs.

Issue was found with GCC -fanalyzer, please follow the link below for
details.

Fixes: e3938177 ("can: m_can: Disable IRQs on FIFO bus errors")
Link: https://lore.kernel.org/all/20211107050755.70655-1-mailhol.vincent@wanadoo.fr
Cc: stable@vger.kernel.org
Cc: Matt Kline <matt@bitbashing.io>
Signed-off-by: NVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

With the design of this driver, this condition is often triggered.
However, the counter that this interrupt indicates an overflow is never
read either, so overflowing is harmless.

On my system, when a CAN bus starts flapping up and down, this locks up
the whole system with lots of interrupts and printks.

Specifically, this interrupt indicates the CEL field of ECR has
overflowed. All reads of ECR mask out CEL.

Fixes: e0d1f481 ("can: m_can: add Bosch M_CAN controller support")
Link: https://lore.kernel.org/all/20211129222628.7490-1-brian.silverman@bluerivertech.com
Cc: stable@vger.kernel.org
Signed-off-by: NBrian Silverman <brian.silverman@bluerivertech.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Give FIFO writes the same treatment as reads to avoid fixed costs of
individual transfers on a slow bus (e.g., tcan4x5x).

Link: https://lore.kernel.org/r/20210817050853.14875-4-matt@bitbashing.ioSigned-off-by: NMatt Kline <matt@bitbashing.io>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

On peripherals communicating over a relatively slow SPI line
(e.g. tcan4x5x), individual transfers have high fixed costs.
This causes the driver to spend most of its time waiting between
transfers and severely limits throughput.

Reduce these overheads by reading more than one word at a time.
Writing could get a similar treatment in follow-on commits.

Link: https://lore.kernel.org/r/20210817050853.14875-3-matt@bitbashing.ioSigned-off-by: NMatt Kline <matt@bitbashing.io>
[mkl: remove __packed from struct id_and_dlc]
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

If FIFO reads or writes fail due to the underlying regmap (e.g., SPI)
I/O, propagate that up to the m_can driver, log an error, and disable
interrupts, similar to the mcp251xfd driver.

While reworking the FIFO functions to add this error handling,
add support for bulk reads and writes of multiple registers.

Link: https://lore.kernel.org/r/20210817050853.14875-2-matt@bitbashing.ioSigned-off-by: NMatt Kline <matt@bitbashing.io>
[mkl: re-wrap long lines, remove WARN_ON, convert to netdev block comments]
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

This patch fixes the commenting style in the m_can driver.

Fixes: 1be37d3b ("can: m_can: fix periph RX path: use rx-offload to ensure skbs are sent from softirq context")
Fixes: df06fd67 ("can: m_can: m_can_chip_config(): enable and configure internal timestamps")
Link: https://lore.kernel.org/r/20210819111703.599686-2-mkl@pengutronix.de
Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

This patch fixes the setting of the M_CAN_DBTP register contents:
- use DBTP_ (the data bitrate macros) instead of NBTP_ which area used
  for the nominal bitrate
- do not overwrite possibly-existing DBTP_TDC flag by ORing reg_btp
  instead of overwriting

Link: https://lore.kernel.org/r/FRYP281MB06140984ABD9994C0AAF7433D1F69@FRYP281MB0614.DEUP281.PROD.OUTLOOK.COM
Fixes: 20779943 ("can: m_can: use bits.h macros for all regmasks")
Cc: Torin Cooper-Bennun <torin@maxiluxsystems.com>
Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.com>
Signed-off-by: NHussein Alasadi <alasadi@arecs.eu>
[mkl: update patch description, update indention]
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Since commit aee2b3cc ("can: tcan4x5x: fix bittiming const, use
common bittiming from m_can driver") there is no use of the device
specific bit timing parameters (m_can_classdev::bit_timing and struct
m_can_classdev::data_timing).

This patch removes the support for custom bit timing from the driver,
as the common bit timing works for all known IP core implementations.

Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.com>
Link: https://lore.kernel.org/r/20210616102811.2449426-7-mkl@pengutronix.deSigned-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Add support for implementing transceiver node as phy. The max_bitrate
is obtained by getting a phy attribute.

Link: https://lore.kernel.org/r/20210724174001.553047-1-mkl@pengutronix.deSigned-off-by: NFaiz Abbas <faiz_abbas@ti.com>
Signed-off-by: NAswath Govindraju <a-govindraju@ti.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

can: rx-offload: can_rx_offload_threaded_irq_finish(): add new function to be called from threaded interrupt

After reading all CAN frames from the controller in the IRQ handler
and storing them into a skb_queue, the driver calls napi_schedule().
In the napi poll function the skb from the skb_queue are then pushed
into the networking stack.

However if napi_schedule() is called from a threaded IRQ handler this
triggers the following error:

| NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!

To avoid this, create a new rx-offload
function (can_rx_offload_threaded_irq_finish()) with a call to
local_bh_disable()/local_bh_enable() around the napi_schedule() call.

Convert all drivers that call can_rx_offload_irq_finish() from
threaded IRQ context to can_rx_offload_threaded_irq_finish().

Link: https://lore.kernel.org/r/20210724204745.736053-4-mkl@pengutronix.deSuggested-by: NDaniel Glöckner <dg@emlix.com>
Tested-by: NOleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Adding a skb to the skb_queue in rx-offload requires to take a lock.

This commit avoids this by adding an unlocked skb queue that is
appended at the end of the ISR. Having one lock at the end of the ISR
should be OK as the HW is empty, not about to overflow.

Link: https://lore.kernel.org/r/20210724204745.736053-2-mkl@pengutronix.deTested-by: NOleksij Rempel <o.rempel@pengutronix.de>
Co-developed-by: NKurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: NKurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Fixes whitespace in comments titling sections of register masks.

Link: https://lore.kernel.org/r/20210504125123.500553-5-torin@maxiluxsystems.comSigned-off-by: NTorin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Introduce masks for the three RXESC fields (RBDS, F1DS, F0DS) and the
one TXESC field (TBDS). Update m_can_chip_config() to explicitly set all
four fields to the 64-byte option (0x7) (and these defs are renamed to
be more concise).

This is an improvement in maintainability, and also makes it easier to
implement more flexible configuration of the M_CAN buffers in the
future.

Link: https://lore.kernel.org/r/20210504125123.500553-4-torin@maxiluxsystems.comSigned-off-by: NTorin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Ensures that the different CCCR regmasks for m_can revs 3.0.x, 3.1.x,
3.2.x and 3.3.x are clearly distinguishable. Removes incorrect
CCCR_CANFD define. Adds bit fields UTSU and WMM for rev 3.3.x, for
completeness.

Link: https://lore.kernel.org/r/20210504125123.500553-3-torin@maxiluxsystems.comSigned-off-by: NTorin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

This updates m_can.c to exclusively use GENMASK, FIELD_GET, FIELD_PREP
and FIELD_MAX for regmask ops, as is convention in the current kernel
(far less error-prone, far more concise).

Link: https://lore.kernel.org/r/20210504125123.500553-2-torin@maxiluxsystems.comSigned-off-by: NTorin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The m_can_start_xmit() function checks if the cdev->tx_skb is NULL and
returns with NETDEV_TX_BUSY in case tx_sbk is not NULL.

There is a race condition in the m_can_tx_work_queue(), where first
the skb is send to the driver and then the case tx_sbk is set to NULL.
A TX complete IRQ might come in between and wake the queue, which
results in tx_skb not being cleared yet.

Fixes: f524f829 ("can: m_can: Create a m_can platform framework")
Tested-by: NTorin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

In commit 1be37d3b ("can: m_can: fix periph RX path: use
rx-offload to ensure skbs are sent from softirq context") the RX path
for peripherals (i.e. SPI based m_can controllers) was converted to
the rx-offload infrastructure. However, the error handling for
can_rx_offload_queue_sorted() was forgotten.
can_rx_offload_queue_sorted() will return with an error if the
internal queue is full.

This patch adds the missing error handling, by increasing the
rx_fifo_errors.

Fixes: 1be37d3b ("can: m_can: fix periph RX path: use rx-offload to ensure skbs are sent from softirq context")
Link: https://lore.kernel.org/r/20210401084515.1455013-1-mkl@pengutronix.deReported-by: Ncoverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1503583 ("Error handling issues")
Reviewed-by: NKees Cook <keescook@chromium.org>
Cc: Torin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

For peripheral devices, m_can sent skbs directly from a threaded irq
instead of from a softirq context, breaking the tcan4x5x peripheral
driver completely. This patch transitions the driver to use the
rx-offload helper for peripherals, ensuring the skbs are sent from the
correct context, with h/w timestamping to ensure correct ordering.

Link: https://lore.kernel.org/r/20210308102427.63916-4-torin@maxiluxsystems.comSigned-off-by: NTorin Cooper-Bennun <torin@maxiluxsystems.com>
[mkl: m_can_class_register(): update error handling]
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

This is a prerequisite for transitioning the m_can driver to rx-offload,
which works best with TX and RX timestamps.

The timestamps provided by M_CAN are 16-bit, timed according to the
nominal bit timing, and may be prescaled by a multiplier up to 16. We
choose the highest prescalar so that the timestamp wraps every 2^20 bit
times, or 209 ms at a bus speed of 5 Mbit/s. Timestamps will have a
precision of 16 bit times.

Link: https://lore.kernel.org/r/20210308102427.63916-3-torin@maxiluxsystems.comSigned-off-by: NTorin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Add infrastucture to allow internal timestamps from the M_CAN to be
configured and retrieved.

Link: https://lore.kernel.org/r/20210308102427.63916-2-torin@maxiluxsystems.comSigned-off-by: NTorin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

If the CAN net device has been successfully allocated, its private
data structure is impossible to be empty, remove this redundant error
return judgment.

Link: https://lore.kernel.org/r/20210205072559.13241-2-xulin.sun@windriver.comSigned-off-by: NXulin Sun <xulin.sun@windriver.com>
Signed-off-by: NMarc 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
even if the transmission failed for some reason.

To avoid to calculate this length twice, extend can_free_echo_skb() to
return that value. Convert all users of this function, too.

This patch is the natural extension of commit:

| 9420e1d4 ("can: dev: can_get_echo_skb(): extend to return can
|                frame length")

Link: https://lore.kernel.org/r/20210319142700.305648-3-mkl@pengutronix.deSigned-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

For M_CAN peripherals, m_can_rx_handler() was called with quota = 1,
which caused any error handling to block RX from taking place until
the next time the IRQ handler is called. This had been observed to
cause RX to be blocked indefinitely in some cases.

This is fixed by calling m_can_rx_handler with a sensibly high quota.

Fixes: f524f829 ("can: m_can: Create a m_can platform framework")
Link: https://lore.kernel.org/r/20210303144350.4093750-1-torin@maxiluxsystems.comSuggested-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NTorin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>