The bravery continues with the next update and first non-RFC version of the in-kernel logic analyzer based on GPIO polling with local irqs disabled. It has been been tested locally and remotely. It provided satisfactory results. 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 for debugging only, not mass production. 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 v2: * took most of the suggestions from Andy's review. For the things I did not take, I added comments when appropriate. * A *lot* of cleanups to the shell script guided by checkers, mainly 'shellcheck'. This is mainly to ensure that the scripts works on most minimal shells. Tested are 'busybox ash', 'dash', and 'bash'. * a *lot* more error checking and reporting in the script * I found fatal_signal_pending(), so the sampling process is now finally killable \o/ * script sets CPUfreq now to "performance" for the isolated CPU * the acquisition_delay is now measured before each sampling and not only during probe because the probing core is likely not the one used for sampling later Thanks to Andy for many suggestions. A branch with preparation for the Renesas Salvator-XS (R-Car H3 ES2.0 and M3-N tested) and Falcon boards (R-Car V3U) is here: git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/gpio-logic-analyzer-v3 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. Thanks and all the best, Wolfram Wolfram Sang (1): gpio: add sloppy logic analyzer using polling .../dev-tools/gpio-sloppy-logic-analyzer.rst | 71 ++++ Documentation/dev-tools/index.rst | 1 + drivers/gpio/Kconfig | 17 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-sloppy-logic-analyzer.c | 340 ++++++++++++++++++ tools/gpio/gpio-sloppy-logic-analyzer | 214 +++++++++++ 6 files changed, 644 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
