linux_dsm_epyc7002/Documentation/ABI/testing/debugfs-cros-ec
Evan Green 8c3166e17c mfd / platform: cros_ec_debugfs: Expose resume result via debugfs
For ECs that support it, the EC returns the number of slp_s0
transitions and whether or not there was a timeout in the resume
response. Expose the last resume result to usermode via debugfs so
that usermode can detect and report S0ix timeouts.

Signed-off-by: Evan Green <evgreen@chromium.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
2019-07-01 15:39:11 +02:00

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What: /sys/kernel/debug/<cros-ec-device>/console_log
Date: September 2017
KernelVersion: 4.13
Description:
If the EC supports the CONSOLE_READ command type, this file
can be used to grab the EC logs. The kernel polls for the log
and keeps its own buffer but userspace should grab this and
write it out to some logs.
What: /sys/kernel/debug/<cros-ec-device>/panicinfo
Date: September 2017
KernelVersion: 4.13
Description:
This file dumps the EC panic information from the previous
reboot. This file will only exist if the PANIC_INFO command
type is supported by the EC.
What: /sys/kernel/debug/<cros-ec-device>/pdinfo
Date: June 2018
KernelVersion: 4.17
Description:
This file provides the port role, muxes and power debug
information for all the USB PD/type-C ports available. If
the are no ports available, this file will be just an empty
file.
What: /sys/kernel/debug/<cros-ec-device>/uptime
Date: June 2019
KernelVersion: 5.3
Description:
A u32 providing the time since EC booted in ms. This is
is used for synchronizing the AP host time with the EC
log. An error is returned if the command is not supported
by the EC or there is a communication problem.
What: /sys/kernel/debug/<cros-ec-device>/last_resume_result
Date: June 2019
KernelVersion: 5.3
Description:
Some ECs have a feature where they will track transitions to
the (Intel) processor's SLP_S0 line, in order to detect cases
where a system failed to go into S0ix. When the system resumes,
an EC with this feature will return a summary of SLP_S0
transitions that occurred. The last_resume_result file returns
the most recent response from the AP's resume message to the EC.
The bottom 31 bits contain a count of the number of SLP_S0
transitions that occurred since the suspend message was
received. Bit 31 is set if the EC attempted to wake the
system due to a timeout when watching for SLP_S0 transitions.
Callers can use this to detect a wake from the EC due to
S0ix timeouts. The result will be zero if no suspend
transitions have been attempted, or the EC does not support
this feature.
Output will be in the format: "0x%08x\n".