On Mon, 17 Jun 2019, Evan Green wrote:
> 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>
This still needs a platform/chrome Ack.
> ---
>
> 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 | 7 +++++++
> include/linux/mfd/cros_ec.h | 1 +
> 4 files changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/debugfs-cros-ec
> b/Documentation/ABI/testing/debugfs-cros-ec
> index 573a82d23c89..008b31422079 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/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 cd3fb9c22a44..663bebf699bf 100644
> --- a/drivers/platform/chrome/cros_ec_debugfs.c
> +++ b/drivers/platform/chrome/cros_ec_debugfs.c
> @@ -447,6 +447,13 @@ static int cros_ec_debugfs_probe(struct platform_device
> *pd)
> debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
> &cros_ec_uptime_fops);
>
> + if (!strcmp(ec->class_dev.kobj.name, CROS_EC_DEV_NAME)) {
> + 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;
> };
>
> /**
--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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