Since all CAN controllers drivers seem to support automatic recovery (for
any future drivers for hardware without this hardware capability this can
easily be implemented in the driver), change the Zephyr CAN controller API
policy to:
- Always enable automatic bus recovery upon driver initialization,
regardless of Kconfig options. Since CAN controllers are initialized in
"stopped" state, no unwanted bus-off recovery will be started at this
point.
- Invert and rename the Kconfig CONFIG_CAN_AUTO_BUS_OFF_RECOVERY, which is
enabled by default, to CONFIG_CAN_MANUAL_RECOVERY_MODE, which is disabled
by default. Enabling CONFIG_CAN_MANUAL_RECOVERY_MODE=y enables support
for the can_recover() API function and a new manual recovery mode (see
next bullet). Keeping this guarded by Kconfig allows keeping the flash
footprint down for applications not using manual bus-off recovery.
- Introduce a new CAN controller operational mode
CAN_MODE_MANUAL_RECOVERY. Support for this is only enabled if
CONFIG_CAN_MANUAL_RECOVERY_MODE=y. Having this as a mode allows
applications to inquire whether the CAN controller supports manual
recovery mode via the can_get_capabilities() API function and either fail
or rely on automatic recovery - and it allows CAN controller drivers not
supporting manual recovery mode to fail early in can_set_mode() during
application startup instead of failing when can_recover() is called at a
later point in time.
Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
A growing number of CAN controllers do not have support for individual RX
hardware filters based on the Remote Transmission Request (RTR) bit. This
leads to various work-arounds on the driver level mixing hardware and
software filtering.
As the use of RTR frames is discouraged by CAN in Automation (CiA) - and
not even supported by newer standards, e.g. CAN FD - this often leads to
unnecessary overhead, added complexity, and worst-case to non-portable
behavior between various CAN controller drivers.
Instead, move to a simpler approach where the ability to accept/reject RTR
frames is globally configured via Kconfig. By default, all incoming RTR
frames are rejected at the driver level, a setting which can be supported
in hardware by most in-tree CAN controllers drivers.
Legacy applications or protocol implementations, where RTR reception is
required, can now select CONFIG_CAN_ACCEPT_RTR to accept incoming RTR
frames matching added CAN filters. These applications or protocols will
need to distinguish between RTR and data frames in their respective CAN RX
frame handling routines.
Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
As both C and C++ standards require applications running under an OS to
return 'int', adapt that for Zephyr to align with those standard. This also
eliminates errors when building with clang when not using -ffreestanding,
and reduces the need for compiler flags to silence warnings for both clang
and gcc.
Most of these changes were automated using coccinelle with the following
script:
@@
@@
- void
+ int
main(...) {
...
- return;
+ return 0;
...
}
Approximately 40 files had to be edited by hand as coccinelle was unable to
fix them.
Signed-off-by: Keith Packard <keithp@keithp.com>
Use printf() instead of printk() for printing sample output. According to
the documentation Zephyr printk() and friends are for printing kernel debug
messages.
With printf() instead of printk() the CAN counter sample passes twister
test execution on native_posix and native_posix_64.
Fixes: #50570
Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
The can_frame and can_filter structs support a number of different flags
(standard/extended CAN ID type, Remote Transmission Request, CAN-FD format,
Bit Rate Switch, ...). Each of these flags is represented as a discrete bit
in the given structure.
This design pattern requires every user of these structs to initialize all
of these flags to either 0 or 1, which does not scale well for future flag
additions.
Some of these flags have associated enumerations to be used for assignment,
some do not. CAN drivers and protocols tend to rely on the logical value of
the flag instead of using the enumeration, leading to a very fragile
API. The enumerations are used inconsistently between the can_frame and
can_filter structures, which further complicates the API.
Instead, convert these flags to bitfields with separate flag definitions
for the can_frame and can_filter structures. This API allows for future
extensions without having to revisit existing users of the two
structures. Furthermore, this allows driver to easily check for unsupported
flags in the respective API calls.
As this change leads to the "id_mask" field of the can_filter to be the
only mask present in that structure, rename it to "mask" for simplicity.
Fixes: #50776
Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
Up until now, the Zephyr CAN controller drivers set a default bitrate (or
timing) specified via devicetree and start the CAN controller in their
respective driver initialization functions.
This is fine for CAN nodes using only one fixed bitrate, but if the bitrate
is set by the user (e.g. via a DIP-switch or other HMI which is very
common), the CAN driver will still initialise with the default
bitrate/timing at boot and use this until the application has determined
the requested bitrate/timing and set it using
can_set_bitrate()/can_set_timing().
During this period, the CAN node will potentially destroy valid CAN frames
on the CAN bus (which is using the soon-to-be-set-by-the-application
bitrate) by sending error frames. This causes interruptions to the ongoing
CAN bus traffic when a Zephyr-based CAN node connected to the bus is
(re-)booted.
Instead, require all configuration (setting bitrate, timing, or mode) to
take place when the CAN controller is stopped. This maps nicely to entering
"reset mode" (called "configuration mode" or "freeze mode" for some CAN
controller implementations) when stopping and exiting this mode when
starting the CAN controller.
Fixes: #45304
Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
