Okay, this one is maybe a bit brave, let's see if it is suitable for upstream. This is an in-kernel logic analyzer based on GPIO polling with local irqs disabled. Besides the driver, there is a script which isolates a CPU to get towards 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. So, I wonder if we want to provide this for others, too, and have it in Linus' tree. Documentation is within the patch, to get a better idea what this is all about. 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/topic/gpio-logic-analyzer The documentation is also available online on the elinux wiki: https://elinux.org/Kernel_GPIO_Logic_analyzer Looking forward to comments. 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 simple logic analyzer using polling .../dev-tools/gpio-logic-analyzer.rst | 63 ++++ Documentation/dev-tools/index.rst | 1 + .../bindings/misc/gpio-logic-analyzer.yaml | 40 ++ drivers/misc/Kconfig | 12 + drivers/misc/Makefile | 1 + drivers/misc/gpio-logic-analyzer.c | 355 ++++++++++++++++++ tools/debugging/gpio-logic-analyzer | 156 ++++++++ 7 files changed, 628 insertions(+) create mode 100644 Documentation/dev-tools/gpio-logic-analyzer.rst create mode 100644 Documentation/devicetree/bindings/misc/gpio-logic-analyzer.yaml create mode 100644 drivers/misc/gpio-logic-analyzer.c create mode 100755 tools/debugging/gpio-logic-analyzer -- 2.30.0
