mirror of https://gitee.com/openkylin/linux.git
26285f1359
Vladimir Oltean says: ==================== Unlock new potential in SJA1105 with PTP system timestamping The SJA1105 being an automotive switch means it is designed to live in a set-and-forget environment, far from the configure-at-runtime nature of Linux. Frequently resetting the switch to change its static config means it loses track of its PTP time, which is not good. This patch series implements PTP system timestamping for this switch (using the API introduced for SPI here: https://www.mail-archive.com/netdev@vger.kernel.org/msg316725.html), adding the following benefits to the driver: - When under control of a user space PTP servo loop (ptp4l, phc2sys), the loss of sync during a switch reset is much more manageable, and the switch still remains in the s2 (locked servo) state. - When synchronizing the switch using the software technique (based on reading clock A and writing the value to clock B, as opposed to relying on hardware timestamping), e.g. by using phc2sys, the sync accuracy is vastly improved due to the fact that the actual switch PTP time can now be more precisely correlated with something of better precision (CLOCK_REALTIME). The issue is that SPI transfers are inherently bad for measuring time with low jitter, but the newly introduced API aims to alleviate that issue somewhat. This series is also a requirement for a future patch set that adds full time-aware scheduling offload support for the switch. ==================== Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| 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 | ||
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.