google/chromeec: Add new helper function to read MKBP events

This change adds a new helper function google_chromeec_get_mkbp_event
that allows coreboot to query EC for the next available MKBP event.

Change-Id: Ia6d64586ca62378d08025c96c2689c00c816041f
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/22007
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/ec/google/chromeec/ec.c

@@ -160,6 +160,21 @@ int google_chromeec_clear_events_b(u32 mask)
 		EC_CMD_HOST_EVENT_CLEAR_B, mask);
 }
 
+int google_chromeec_get_mkbp_event(struct ec_response_get_next_event *event)
+{
+	struct chromeec_command cmd;
+
+	cmd.cmd_code = EC_CMD_GET_NEXT_EVENT;
+	cmd.cmd_version = 0;
+	cmd.cmd_data_in = NULL;
+	cmd.cmd_size_in = 0;
+	cmd.cmd_data_out = event;
+	cmd.cmd_size_out = sizeof(*event);
+	cmd.cmd_dev_index = 0;
+
+	return google_chromeec_command(&cmd);
+}
+
 /* Get the current device event mask */
 uint32_t google_chromeec_get_device_enabled_events(void)
 {

src/ec/google/chromeec/ec.h

@@ -126,4 +126,10 @@ struct google_chromeec_event_info {
 void google_chromeec_events_init(const struct google_chromeec_event_info *info,
 					bool is_s3_wakeup);
 
+/*
+ * Get next available MKBP event in ec_response_get_next_event. Returns 0 on
+ * success, < 0 otherwise.
+ */
+int google_chromeec_get_mkbp_event(struct ec_response_get_next_event *event);
+
 #endif /* _EC_GOOGLE_CHROMEEC_EC_H */