mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2025-01-22 22:04:47 +08:00
d99755f71a
Add the netlink interface for TDC parameters of struct can_tdc_const
and can_tdc.
Contrary to the can_bittiming(_const) structures for which there is
just a single IFLA_CAN(_DATA)_BITTMING(_CONST) entry per structure,
here, we create a nested entry IFLA_CAN_TDC. Within this nested entry,
additional IFLA_CAN_TDC_TDC* entries are added for each of the TDC
parameters of the newly introduced struct can_tdc_const and struct
can_tdc.
For struct can_tdc_const, these are:
IFLA_CAN_TDC_TDCV_MIN
IFLA_CAN_TDC_TDCV_MAX
IFLA_CAN_TDC_TDCO_MIN
IFLA_CAN_TDC_TDCO_MAX
IFLA_CAN_TDC_TDCF_MIN
IFLA_CAN_TDC_TDCF_MAX
For struct can_tdc, these are:
IFLA_CAN_TDC_TDCV
IFLA_CAN_TDC_TDCO
IFLA_CAN_TDC_TDCF
This is done so that changes can be applied in the future to the
structures without breaking the netlink interface.
The TDC netlink logic works as follow:
* CAN_CTRLMODE_FD is not provided:
- if any TDC parameters are provided: error.
- TDC parameters not provided: TDC parameters unchanged.
* CAN_CTRLMODE_FD is provided and is false:
- TDC is deactivated: both the structure and the
CAN_CTRLMODE_TDC_{AUTO,MANUAL} flags are flushed.
* CAN_CTRLMODE_FD provided and is true:
- CAN_CTRLMODE_TDC_{AUTO,MANUAL} and tdc{v,o,f} not provided: call
can_calc_tdco() to automatically decide whether TDC should be
activated and, if so, set CAN_CTRLMODE_TDC_AUTO and uses the
calculated tdco value.
- CAN_CTRLMODE_TDC_AUTO and tdco provided: set
CAN_CTRLMODE_TDC_AUTO and use the provided tdco value. Here,
tdcv is illegal and tdcf is optional.
- CAN_CTRLMODE_TDC_MANUAL and both of tdcv and tdco provided: set
CAN_CTRLMODE_TDC_MANUAL and use the provided tdcv and tdco
value. Here, tdcf is optional.
- CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive. Whenever
one flag is turned on, the other will automatically be turned
off. Providing both returns an error.
- Combination other than the one listed above are illegal and will
return an error.
N.B. above rules mean that whenever CAN_CTRLMODE_FD is provided, the
previous TDC values will be overwritten. The only option to reuse
previous TDC value is to not provide CAN_CTRLMODE_FD.
All the new parameters are defined as u32. This arbitrary choice is
done to mimic the other bittiming values with are also all of type
u32. An u16 would have been sufficient to hold the TDC values.
This patch completes below series (c.f. [1]):
- commit
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.