The bravery continues with the second RFC for the in-kernel logic analyzer based on GPIO polling with local irqs disabled. Besides the driver, there is also a script which isolates a CPU to achieve the best possible result. I am aware of the latency limitations. However, the intention is only for debugging. Especially for remote debugging and to get a first impression, this has already been useful. Documentation is within the patch, to get a better idea what this is all about. Changes since RFC v1: * moved from misc/ to gpio/. Thanks to Linus and Bartosz for offering a home for this * renamed from "simple logic analyzer" to "sloppy logic analyzer" everywhere to make its limitations crystal clear * moved the parser for trigger data from the kernel into the script. Much cleaner kernel code but passing binary data now. We'll see... * all gpios now must be named. This removes ugly fallback code and allows to use generic device properties instead of OF properties only. * added and updated documentation * triggers are also now checked at sample speed, not full speed * replaced pr_* printouts with dev_* * removed bashisms in the script (tested with bash, dash, and busybox ash) * depends on EXPERT now * small bugfixes, refactoring, cleanups all around Thanks to Andy, Linus, Randy, and Ulrich for suggestions and testing. A branch with preparation for the Renesas Salvator-XS boards is here: git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/gpio-logic-analyzer-v2 The documentation is also available online on the elinux wiki: https://elinux.org/Kernel_GPIO_Logic_analyzer Looking forward to comments and especially further tests with different use cases than mine. I have looked enough at the code, fresh view would really help. And still, if somebody has a pointer how to detect if a task was requested to be killed (while irqs and preemption are disabled), I'd appreciate that to avoid the currently unkillable sub-process. All the best, Wolfram Wolfram Sang (1): misc: add sloppy logic analyzer using polling .../dev-tools/gpio-sloppy-logic-analyzer.rst | 72 ++++ Documentation/dev-tools/index.rst | 1 + drivers/gpio/Kconfig | 17 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-sloppy-logic-analyzer.c | 317 ++++++++++++++++++ tools/gpio/gpio-sloppy-logic-analyzer | 200 +++++++++++ 6 files changed, 608 insertions(+) create mode 100644 Documentation/dev-tools/gpio-sloppy-logic-analyzer.rst create mode 100644 drivers/gpio/gpio-sloppy-logic-analyzer.c create mode 100755 tools/gpio/gpio-sloppy-logic-analyzer -- 2.30.2
