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 <evgr...@chromium.org> --- Changes in v3: - Expose the debugfs file on all EC types (Enric) Changes in v2: - Moved from sysfs to debugfs (Enric) - Added documentation (Enric) --- Documentation/ABI/testing/debugfs-cros-ec | 22 ++++++++++++++++++++++ drivers/mfd/cros_ec.c | 6 +++++- drivers/platform/chrome/cros_ec_debugfs.c | 5 +++++ include/linux/mfd/cros_ec.h | 1 + 4 files changed, 33 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/debugfs-cros-ec b/Documentation/ABI/testing/debugfs-cros-ec index 573a82d23c89..1fe0add99a2a 100644 --- a/Documentation/ABI/testing/debugfs-cros-ec +++ b/Documentation/ABI/testing/debugfs-cros-ec @@ -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 +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". diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c index 5d5c41ac3845..2a9ac5213893 100644 --- a/drivers/mfd/cros_ec.c +++ b/drivers/mfd/cros_ec.c @@ -102,12 +102,16 @@ 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 = + buf.u.resp1.resume_response.sleep_transitions; + WARN_ONCE(buf.u.resp1.resume_response.sleep_transitions & EC_HOST_RESUME_SLEEP_TIMEOUT, "EC detected sleep transition timeout. Total slp_s0 transitions: %d", buf.u.resp1.resume_response.sleep_transitions & EC_HOST_RESUME_SLEEP_TRANSITIONS_MASK); + } return ret; } diff --git a/drivers/platform/chrome/cros_ec_debugfs.c b/drivers/platform/chrome/cros_ec_debugfs.c index 7ee060743844..967c78abfdd3 100644 --- a/drivers/platform/chrome/cros_ec_debugfs.c +++ b/drivers/platform/chrome/cros_ec_debugfs.c @@ -447,6 +447,11 @@ static int cros_ec_debugfs_probe(struct platform_device *pd) debugfs_create_file("uptime", 0444, debug_info->dir, debug_info, &cros_ec_uptime_fops); + debugfs_create_x32("last_resume_result", + 0444, + debug_info->dir, + &ec->ec_dev->last_resume_result); + ec->debug_info = debug_info; dev_set_drvdata(&pd->dev, ec); diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h index 5ddca44be06d..45aba26db964 100644 --- a/include/linux/mfd/cros_ec.h +++ b/include/linux/mfd/cros_ec.h @@ -155,6 +155,7 @@ 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; }; /** -- 2.20.1