Commit 8c3166e1 authored by Evan Green's avatar Evan Green Committed by Enric Balletbo i Serra

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: default avatarEvan Green <>
Acked-by: default avatarLee Jones <>
Signed-off-by: default avatarEnric Balletbo i Serra <>
parent c18e6ea1
......@@ -32,3 +32,25 @@ Description:
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
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".
......@@ -110,12 +110,16 @@ static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
/* For now, report failure to transition to S0ix with a warning. */
if (ret >= 0 && ec_dev->host_sleep_v1 &&
(sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
(sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME)) {
ec_dev->last_resume_result =
WARN_ONCE(buf.u.resp1.resume_response.sleep_transitions &
"EC detected sleep transition timeout. Total slp_s0 transitions: %d",
buf.u.resp1.resume_response.sleep_transitions &
return ret;
......@@ -447,6 +447,9 @@ static int cros_ec_debugfs_probe(struct platform_device *pd)
debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
ec->debug_info = debug_info;
dev_set_drvdata(&pd->dev, ec);
......@@ -163,6 +163,7 @@ struct cros_ec_device {
struct ec_response_get_next_event_v1 event_data;
int event_size;
u32 host_event_wake_mask;
u32 last_resume_result;
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