| From: |
| Wolfram Sang <wsa+renesas-AT-sang-engineering.com> |
| To: |
| linux-kernel-AT-vger.kernel.org |
| Subject: |
| [PATCH RFC/RFT 0/1] add simple logic analyzer using polling |
| Date: |
| Tue, 30 Mar 2021 10:56:54 +0200 |
| Message-ID: |
| <20210330085655.12615-1-wsa+renesas@sang-engineering.com> |
| Cc: |
| linux-renesas-soc-AT-vger.kernel.org, linux-gpio-AT-vger.kernel.org, Wolfram Sang <wsa+renesas-AT-sang-engineering.com> |
| Archive-link: |
| Article |
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
