can: Kconfig: add CONFIG_CAN_RX_OFFLOAD

Only a few drivers rely on the CAN rx offload framework (as of the
writing of this patch, only four: flexcan, m_can, mcp251xfd and
ti_hecc). Split it out of can-dev and add a new config symbol:
CAN_RX_OFFLOAD.

The drivers relying on CAN rx offload are in different sub
folders. Make CAN_RX_OFFLOAD an hidden option and tag all the drivers
depending on that feature with "select CAN_RX_OFFLOAD" so that the
option gets automatically enabled if and only if one of those drivers
is chosen.

Link: https://lore.kernel.org/all/20220610143009.323579-5-mailhol.vincent@wanadoo.fr
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Acked-by: Max Staudt <max@enpas.org>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: m_can: add PCI glue driver for Intel Elkhart Lake

Add support for M_CAN controller on Intel Elkhart Lake attached to the PCI bus.
It integrates the Bosch M_CAN controller with Message RAM and the wrapper IP
block with additional registers which all of them are within the same MMIO
range.

Currently only interrupt control register from wrapper IP is used and the MRAM
configuration is expected to come from the firmware via "bosch,mram-cfg" device
property and parsed by m_can.c core.

Initial implementation is done by Felipe Balbi while he was working at Intel
with later changes from Raymond Tan and me.

Co-developed-by: Felipe Balbi (Intel) <balbi@kernel.org>
Co-developed-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Felipe Balbi (Intel) <balbi@kernel.org>
Signed-off-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Link: https://lore.kernel.org/r/20201117160827.3636264-1-jarkko.nikula@linux.intel.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: m_can: Kconfig: convert the into menu

Since there is more than one base driver for the m_can core, let's
convert this into a menu.

Link: https://lore.kernel.org/r/20201130133713.269256-4-mkl@pengutronix.de
Reviewed-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: tcan4x5x: replace depends on REGMAP_SPI with depends on SPI

regmap is a library function that gets selected by drivers that need it. No
driver modules should depend on it. Instead depends on SPI and select
REGMAP_SPI. Depending on REGMAP_SPI makes this driver only build if another
driver already selected REGMAP_SPI, as the symbol can't be selected through the
menu kernel configuration.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: http://lore.kernel.org/r/20200413141013.506613-1-enric.balletbo@collabora.com
Reviewed-by: Dan Murphy <dmurphy@ti.com>
Fixes: 5443c226ba91 ("can: tcan4x5x: Add tcan4x5x driver to the kernel")
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: drivers: fix spelling mistakes

This patch fixes spelling erros found by "codespell" in the
drivers/net/can subtree.

Link: https://lore.kernel.org/r/20200915223527.1417033-6-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

can: tcan4x5x: Add tcan4x5x driver to the kernel

Add the TCAN4x5x SPI CAN driver.

This device uses the Bosch MCAN IP core along with a SPI interface map.
Register to the MCAN common core code to manage the MCAN IP.

This device has a special method to indicate a write/read operation on
the data payload.

Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: m_can: Create a m_can platform framework

Create a m_can platform framework that peripheral
devices can register to and use common code and register sets.
The peripheral devices may provide read/write and configuration
support of the IP.

Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Acked-by: Faiz Abbas <faiz_abbas@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

can: m_can: add CONFIG_HAS_IOMEM dependence

m_can uses io memory which makes it not compilable on architectures
without HAS_IOMEM such as UML:

drivers/built-in.o: In function `m_can_plat_probe':
m_can.c:(.text+0x218cc5): undefined reference to `devm_ioremap_resource'
m_can.c:(.text+0x218df9): undefined reference to `devm_ioremap'

Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: m_can: add Bosch M_CAN controller support

The patch adds the basic CAN TX/RX function support for Bosch M_CAN controller.
For TX, only one dedicated tx buffer is used for sending data.
For RX, RXFIFO 0 is used for receiving data to avoid overflow.
Rx FIFO 1 and Rx Buffers are not used currently, as well as Tx Event FIFO.

Due to the message ram can be shared by multi m_can instances
and the fifo element is configurable which is SoC dependant,
the design is to parse the message ram related configuration data from device
tree rather than hardcode define it in driver which can make the message
ram sharing fully transparent to M_CAN controller driver,
then we can gain better driver maintainability and future features upgrade.

M_CAN also supports CANFD protocol features like data payload up to 64 bytes
and bitrate switch at runtime, however, this patch still does not add the
support for these features.

Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Varka Bhadram <varkabhadram@gmail.com>
Signed-off-by: Dong Aisheng <b29396@freescale.com>
Reviewed-by: Varka Bhadram <varkabhadram@gmail.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
[mkl: Squahed semicolon cleanup by Fengguang Wu]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>