Date:   Tue, 7 Feb 2017 16:12:24 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Thierry Escande <thierry.escande@...labora.com>
Cc:     Benson Leung <bleung@...omium.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] cros_ec: Don't signal wake event for non-wake host
 events

On Wed, 25 Jan 2017, Thierry Escande wrote:

> From: Shawn Nematbakhsh <shawnn@...omium.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@...omium.org>
> Signed-off-by: Thierry Escande <thierry.escande@...labora.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?

> +	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?

... 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?

> +		/* 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

> +	}
> +
> +	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;

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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