[RFC PATCH v2 0/4] can: bxcan: add support for ST bxCAN controller

From: Dario Binacchi
Date: Sat Aug 20 2022 - 04:30:15 EST


The series adds support for the basic extended CAN controller (bxCAN)
found in many low- to middle-end STM32 SoCs.

The driver design (one core module and one driver module) was inspired
by other ST drivers (e. g. drivers/iio/adc/stm32-adc.c,
drivers/iio/adc/stm32-adc-core.c) where device instances share resources.
The shared resources functions are implemented in the core module, the
device driver in a separate module.

The driver has been tested on the stm32f469i-discovery board with a
kernel version 5.19.0-rc2 in loopback + silent mode:

ip link set can0 type can bitrate 125000 loopback on listen-only on
ip link set up can0
candump can0 -L &
cansend can0 300#AC.AB.AD.AE.75.49.AD.D1

For uboot and kernel compilation, as well as for rootfs creation I used
buildroot:

make stm32f469_disco_sd_defconfig
make

but I had to patch can-utils and busybox as can-utils and iproute are
not compiled for MMU-less microcotrollers. In the case of can-utils,
replacing the calls to fork() with vfork(), I was able to compile the
package with working candump and cansend applications, while in the
case of iproute, I ran into more than one problem and finally I decided
to extend busybox's ip link command for CAN-type devices. I'm still
wondering if it was really necessary, but this way I was able to test
the driver.

Changes in v2:
- Change the file name into 'st,stm32-bxcan-core.yaml'.
- Rename compatibles:
- st,stm32-bxcan-core -> st,stm32f4-bxcan-core
- st,stm32-bxcan -> st,stm32f4-bxcan
- Rename master property to st,can-master.
- Remove the status property from the example.
- Put the node child properties as required.
- Remove a blank line.
- Fix sparse errors.
- Create a MAINTAINERS entry.
- Remove the print of the registers address.
- Remove the volatile keyword from bxcan_rmw().
- Use tx ring algorithm to manage tx mailboxes.
- Use can_{get|put}_echo_skb().
- Update DT properties.

Dario Binacchi (4):
dt-bindings: net: can: add STM32 bxcan DT bindings
ARM: dts: stm32: add CAN support on stm32f429
ARM: dts: stm32: add pin map for CAN controller on stm32f4
can: bxcan: add support for ST bxCAN controller

.../bindings/net/can/st,stm32-bxcan.yaml | 136 +++
MAINTAINERS | 7 +
arch/arm/boot/dts/stm32f4-pinctrl.dtsi | 31 +
arch/arm/boot/dts/stm32f429.dtsi | 30 +
drivers/net/can/Kconfig | 1 +
drivers/net/can/Makefile | 1 +
drivers/net/can/bxcan/Kconfig | 34 +
drivers/net/can/bxcan/Makefile | 4 +
drivers/net/can/bxcan/bxcan-core.c | 200 ++++
drivers/net/can/bxcan/bxcan-core.h | 33 +
drivers/net/can/bxcan/bxcan-drv.c | 1043 +++++++++++++++++
11 files changed, 1520 insertions(+)
create mode 100644 Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml
create mode 100644 drivers/net/can/bxcan/Kconfig
create mode 100644 drivers/net/can/bxcan/Makefile
create mode 100644 drivers/net/can/bxcan/bxcan-core.c
create mode 100644 drivers/net/can/bxcan/bxcan-core.h
create mode 100644 drivers/net/can/bxcan/bxcan-drv.c

--
2.32.0