Re: [PATCH 3/3] cros_ec: Don't signal wake event for non-wake host events

[Thierry Escande <thierry.escande@collabora.com>]

Hi Lee,

On 07/02/2017 17:12, Lee Jones wrote:
> On Wed, 25 Jan 2017, Thierry Escande wrote:
>
>> From: Shawn Nematbakhsh <shawnn@chromium.org>
>>
>> The subset of wake-enabled host events is defined by the EC, but the EC
>> may still send non-wake host events if we're in the process of
>> suspending. Get the mask of wake-enabled host events from the EC and
>> filter out non-wake events to prevent spurious aborted suspend
>> attempts.
>>
>> Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
>> Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
>> ---
>>  drivers/mfd/cros_ec.c                   | 14 ++++++--
>>  drivers/platform/chrome/cros_ec_proto.c | 60 +++++++++++++++++++++++++++++++++
>>  include/linux/mfd/cros_ec.h             | 12 +++++++
>>  3 files changed, 84 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
>> index abd8342..510dfbb 100644
>> --- a/drivers/mfd/cros_ec.c
>> +++ b/drivers/mfd/cros_ec.c
>> @@ -53,12 +53,22 @@ static const struct mfd_cell ec_pd_cell = {
>>  static irqreturn_t ec_irq_thread(int irq, void *data)
>>  {
>>  	struct cros_ec_device *ec_dev = data;
>> +	u8 wake_event = 1;
>
> Bool, true?
Ok.

>
>> +	u32 host_event;
>>  	int ret;
>>
>> -	if (device_may_wakeup(ec_dev->dev))
>> +	ret = cros_ec_get_next_event(ec_dev);
>
> What does (ret == 0) mean?
The get_next_event() API called from cros_ec_get_next_event() only sets 
event_data in the ec_dev structure if the command has actually been 
sent. So (ret == 0) is not treated as an error and is silently ignored. 
In this case, the interrupt is treated as a wake event.

>
> ... and is is possible for (ret < 0)?
>
>> +	if (ret > 0 && ec_dev->mkbp_event_supported) {
>
> cros_ec_get_host_event() checks for (ec_dev->mkbp_event_supported)
> anyway, so you can drop it here no?
Sure but we only need to call cros_ec_get_host_event() if 
mkbp_event_supported is true. Anyway, I'll move the host_event check 
with cros_ec_get_host_event() into cros_ec_get_next_event() to avoid 
this double check.

>
>> +		/* Don't signal wake event for non-wake host events */
>> +		host_event = cros_ec_get_host_event(ec_dev);
>> +		if (host_event && !(host_event & ec_dev->host_event_wake_mask))
>> +			wake_event = 0;
>
> false
Will do.

Thanks,
  Thierry

>
>> +	}
>> +
>> +	if (wake_event && device_may_wakeup(ec_dev->dev))
>>  		pm_wakeup_event(ec_dev->dev, 0);
>>
>> -	ret = cros_ec_get_next_event(ec_dev);
>>  	if (ret > 0)
>>  		blocking_notifier_call_chain(&ec_dev->event_notifier,
>>  					     0, ec_dev);
>> diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
>> index 256249b..a216a32 100644
>> --- a/drivers/platform/chrome/cros_ec_proto.c
>> +++ b/drivers/platform/chrome/cros_ec_proto.c
>> @@ -150,6 +150,40 @@ int cros_ec_check_result(struct cros_ec_device *ec_dev,
>>  }
>>  EXPORT_SYMBOL(cros_ec_check_result);
>>
>> +/*
>> + * cros_ec_get_host_event_wake_mask
>> + *
>> + * Get the mask of host events that cause wake from suspend.
>> + *
>> + * @ec_dev: EC device to call
>> + * @msg: message structure to use
>> + * @mask: result when function returns >=0.
>> + *
>> + * LOCKING:
>> + * the caller has ec_dev->lock mutex, or the caller knows there is
>> + * no other command in progress.
>> + */
>> +static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
>> +					    struct cros_ec_command *msg,
>> +					    uint32_t *mask)
>> +{
>> +	struct ec_response_host_event_mask *r;
>> +	int ret;
>> +
>> +	msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
>> +	msg->version = 0;
>> +	msg->outsize = 0;
>> +	msg->insize = sizeof(*r);
>> +
>> +	ret = send_command(ec_dev, msg);
>> +	if (ret > 0) {
>> +		r = (struct ec_response_host_event_mask *)msg->data;
>> +		*mask = r->mask;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>>  static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
>>  					    int devidx,
>>  					    struct cros_ec_command *msg)
>> @@ -387,6 +421,15 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev)
>>  	else
>>  		ec_dev->mkbp_event_supported = 1;
>>
>> +	/*
>> +	 * Get host event wake mask, assume all events are wake events
>> +	 * if unavailable.
>> +	 */
>> +	ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
>> +					       &ec_dev->host_event_wake_mask);
>> +	if (ret < 0)
>> +		ec_dev->host_event_wake_mask = U32_MAX;
>> +
>>  	ret = 0;
>>
>>  exit:
>> @@ -507,3 +550,20 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev)
>>  		return get_keyboard_state_event(ec_dev);
>>  }
>>  EXPORT_SYMBOL(cros_ec_get_next_event);
>> +
>> +u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
>> +{
>> +	if (WARN_ON(!ec_dev->mkbp_event_supported))
>> +		return 0;
>> +
>> +	if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
>> +		return 0;
>> +
>> +	if (ec_dev->event_size != sizeof(u32)) {
>> +		dev_warn(ec_dev->dev, "Invalid host event size\n");
>> +		return 0;
>> +	}
>> +
>> +	return get_unaligned_le32(&ec_dev->event_data.data.host_event);
>> +}
>> +EXPORT_SYMBOL(cros_ec_get_host_event);
>> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
>> index f62043a..8f37c4e 100644
>> --- a/include/linux/mfd/cros_ec.h
>> +++ b/include/linux/mfd/cros_ec.h
>> @@ -146,6 +146,7 @@ struct cros_ec_device {
>>
>>  	struct ec_response_get_next_event event_data;
>>  	int event_size;
>> +	u32 host_event_wake_mask;
>>  };
>>
>>  /**
>> @@ -297,6 +298,17 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev);
>>   */
>>  int cros_ec_get_next_event(struct cros_ec_device *ec_dev);
>>
>> +/**
>> + * cros_ec_get_host_event - Return a mask of event set by the EC.
>> + *
>> + * Once cros_ec_get_next_event() has been called, if the event source is
>> + * a host event, this function returns the precise event that triggered
>> + * the interrupt.
>> + *
>> + * This function is a helper to know which events are raised.
>> + */
>> +u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
>> +
>>  /* sysfs stuff */
>>  extern struct attribute_group cros_ec_attr_group;
>>  extern struct attribute_group cros_ec_lightbar_attr_group;
>