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

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

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;
+	u32 host_event;
 	int ret;
 
-	if (device_may_wakeup(ec_dev->dev))
+	ret = cros_ec_get_next_event(ec_dev);
+
+	if (ret > 0 && ec_dev->mkbp_event_supported) {
+		/* 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;
+	}
+
+	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;
-- 
2.7.4