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| author | Gwendal Grignou <gwendal@chromium.org> | 2023-03-23 15:29:57 -0700 |
|---|---|---|
| committer | Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> | 2023-04-10 18:09:38 +0000 |
| commit | 8ac6fbf9c5a6fa7f4c56573a9a5973d21475b46c (patch) | |
| tree | 79039caeea9fc8f0714961b5ddb3cc99ebc53887 | |
| parent | 7de11dc636bc6cee6dfbb52b83407710e6257909 (diff) | |
| download | chrome-ec-8ac6fbf9c5a6fa7f4c56573a9a5973d21475b46c.tar.gz | |
docs: Add instructions for tracing ec commands
Document how we can trace ec_commands in the EC console and in the kernel.
BUG=none
BRANCH=none
TEST=Check with
`python3 src/chromium/src/tools/md_browser/md_browser.py -d src/platform/ec/docs`
and go to http://localhost:8080/ap-ec-comm.md
Change-Id: Iaf790dc945b46046b84b9f9574bf9a8e552789a5
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4369567
Reviewed-by: Rob Barnes <robbarnes@google.com>
| -rw-r--r-- | docs/ap-ec-comm.md | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/docs/ap-ec-comm.md b/docs/ap-ec-comm.md index 035e2d7457..4270fca5f8 100644 --- a/docs/ap-ec-comm.md +++ b/docs/ap-ec-comm.md @@ -106,6 +106,20 @@ they're being called with. Different versions of a command may have different parameter or response formats. `EC_CMD_GET_CMD_VERSIONS` returns the versions of the given command supported by the EC. These version numbers start at 0. +## Tracing + +Command tracing can be done on the EC console (`hc debug` command) and/or in +the kernel: +``` +echo 1 > /sys/kernel/debug/tracing/events/cros_ec/enable +cat /sys/kernel/debug/tracing/trace + +369.416372: cros_ec_request_start: version: 0, command: EC_CMD_USB_PD_POWER_INFO +369.420528: cros_ec_request_done: version: 0, command: EC_CMD_USB_PD_POWER_INFO, ec result: EC_RES_SUCCESS, retval: 16 +369.420529: cros_ec_request_start: version: 0, command: EC_CMD_USB_PD_DISCOVERY +369.421383: cros_ec_request_done: version: 0, command: EC_CMD_USB_PD_DISCOVERY, ec result: EC_RES_SUCCESS, retval: 5 +``` + ## Transport-specific details Although the command and response formats are the same across all transports, |