platform/chrome: cros_typec_vdm: Add Attention support

Add support to retrieve VDM attention messages and forward them to the
appropriate alt mode driver.
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230126205620.3714994-2-pmalani@chromium.org

drivers/platform/chrome/cros_ec_typec.c

@@ -1015,6 +1015,14 @@ static void cros_typec_handle_status(struct cros_typec_data *typec, int port_num
 		if (ret < 0)
 			dev_warn(typec->dev, "Failed VDM Reply event clear, port: %d\n", port_num);
 	}
+
+	if (resp.events & PD_STATUS_EVENT_VDM_ATTENTION) {
+		cros_typec_handle_vdm_attention(typec, port_num);
+		ret = cros_typec_send_clear_event(typec, port_num, PD_STATUS_EVENT_VDM_ATTENTION);
+		if (ret < 0)
+			dev_warn(typec->dev, "Failed VDM Attenetion event clear, port: %d\n",
+				 port_num);
+	}
 }
 
 static int cros_typec_port_update(struct cros_typec_data *typec, int port_num)

drivers/platform/chrome/cros_typec_vdm.c

@@ -13,6 +13,46 @@
 #include "cros_ec_typec.h"
 #include "cros_typec_vdm.h"
 
+/*
+ * Retrieves pending VDM attention messages from the EC and forwards them to the altmode driver
+ * based on SVID.
+ */
+void cros_typec_handle_vdm_attention(struct cros_typec_data *typec, int port_num)
+{
+	struct ec_response_typec_vdm_response resp;
+	struct ec_params_typec_vdm_response req = {
+		.port = port_num,
+	};
+	struct typec_altmode *amode;
+	u16 svid;
+	u32 hdr;
+	int ret;
+
+	do {
+		ret = cros_ec_cmd(typec->ec, 0, EC_CMD_TYPEC_VDM_RESPONSE, &req,
+				sizeof(req), &resp, sizeof(resp));
+		if (ret < 0) {
+			dev_warn(typec->dev, "Failed VDM response fetch, port: %d\n", port_num);
+			return;
+		}
+
+		hdr = resp.vdm_response[0];
+		svid = PD_VDO_VID(hdr);
+		dev_dbg(typec->dev, "Received VDM Attention header: %x, port: %d\n", hdr, port_num);
+
+		amode = typec_match_altmode(typec->ports[port_num]->port_altmode,
+					    CROS_EC_ALTMODE_MAX, svid, PD_VDO_OPOS(hdr));
+		if (!amode) {
+			dev_err(typec->dev,
+				"Received VDM for unregistered altmode (SVID:%x), port: %d\n",
+				svid, port_num);
+			return;
+		}
+
+		typec_altmode_attention(amode, resp.vdm_attention[1]);
+	} while (resp.vdm_attention_left);
+}
+
 /*
  * Retrieves a VDM response from the EC and forwards it to the altmode driver based on SVID.
  */

drivers/platform/chrome/cros_typec_vdm.h

@@ -7,6 +7,7 @@
 
 extern struct typec_altmode_ops port_amode_ops;
 
+void cros_typec_handle_vdm_attention(struct cros_typec_data *typec, int port_num);
 void cros_typec_handle_vdm_response(struct cros_typec_data *typec, int port_num);
 
 #endif /*  __CROS_TYPEC_VDM__ */