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SubjectRe: [PATCH v2] platform/chrome: Expose resume result via debugfs
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Hi Evan,

Two few comments and I think I'm fine with it.

On 25/6/19 15:05, Lee Jones wrote:
> 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 <evgreen@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

Thinking about it, as other the other interfaces, I'd do

s/cros_ec/<cros-ec-device>/

I know that for now only cros_ec supports that, but we don't know what will
happen in the future, specially now that the number of cros devices is incrementing.

>> +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)) {

For debugfs I don't care having the file exposed even is not supported, anyway
there are some CROS_EC_DEV_NAME that won't support it, so just make this simple
and create the file always.

>> + 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;
>> };
>>
>> /**
>

Thanks,
~ Enric

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