[RFC PATCH 7/7] typec: tcpm: Add support for sink PPS related messages

[Adam Thomson]

This commit adds sink side support for Get_Status, Status,
Get_PPS_Status and PPS_Status handling. As there's the
potential for a partner to respond with Not_Supported
handling of this message is also added. Sending of
Not_Supported is added is added to handle messages
received but not yet handled.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>
---
 drivers/usb/typec/tcpm.c | 152 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 143 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
index bf3c93a..d12304e 100644
--- a/drivers/usb/typec/tcpm.c
+++ b/drivers/usb/typec/tcpm.c
@@ -28,7 +28,9 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/usb/pd.h>
+#include <linux/usb/pd_ado.h>
 #include <linux/usb/pd_bdo.h>
+#include <linux/usb/pd_ext_sdb.h>
 #include <linux/usb/pd_vdo.h>
 #include <linux/usb/tcpm.h>
 #include <linux/usb/typec.h>
@@ -122,6 +124,11 @@
 	S(SNK_TRYWAIT_VBUS),			\
 	S(BIST_RX),				\
 						\
+	S(GET_STATUS_SEND),			\
+	S(GET_STATUS_SEND_TIMEOUT),		\
+	S(GET_PPS_STATUS_SEND),			\
+	S(GET_PPS_STATUS_SEND_TIMEOUT),		\
+						\
 	S(ERROR_RECOVERY),			\
 	S(PORT_RESET),				\
 	S(PORT_RESET_WAIT_OFF)
@@ -152,6 +159,7 @@ enum pd_msg_request {
 	PD_MSG_NONE = 0,
 	PD_MSG_CTRL_REJECT,
 	PD_MSG_CTRL_WAIT,
+	PD_MSG_CTRL_NOT_SUPP,
 	PD_MSG_DATA_SINK_CAP,
 	PD_MSG_DATA_SOURCE_CAP,
 };
@@ -1288,10 +1296,42 @@ static void vdm_state_machine_work(struct work_struct *work)
 /*
  * PD (data, control) command handling functions
  */
+static inline enum tcpm_state ready_state(struct tcpm_port *port)
+{
+	if (port->pwr_role == TYPEC_SOURCE)
+		return SRC_READY;
+	else
+		return SNK_READY;
+}
 
 static int tcpm_pd_send_control(struct tcpm_port *port,
 				enum pd_ctrl_msg_type type);
 
+static void tcpm_handle_alert(struct tcpm_port *port, const __le32 *payload,
+			      int cnt)
+{
+	u32 p0 = le32_to_cpu(payload[0]);
+	unsigned int type = ado_type(p0);
+
+	if (!type) {
+		tcpm_log(port, "Alert message received with no type");
+		return;
+	}
+
+	/* Just handling non-battery alerts for now */
+	if (!(type & ADO_TYPE_BATT_STATUS_CHANGE)) {
+		switch (port->state) {
+		case SRC_READY:
+		case SNK_READY:
+			tcpm_set_state(port, GET_STATUS_SEND, 0);
+			break;
+		default:
+			tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
+			break;
+		}
+	}
+}
+
 static void tcpm_pd_data_request(struct tcpm_port *port,
 				 const struct pd_message *msg)
 {
@@ -1350,6 +1390,14 @@ static void tcpm_pd_data_request(struct tcpm_port *port,
 			tcpm_set_state(port, BIST_RX, 0);
 		}
 		break;
+	case PD_DATA_ALERT:
+		tcpm_handle_alert(port, msg->payload, cnt);
+		break;
+	case PD_DATA_BATT_STATUS:
+	case PD_DATA_GET_COUNTRY_INFO:
+		tcpm_queue_message(port, PD_MSG_CTRL_NOT_SUPP);
+		/* Currently unsupported */
+		break;
 	default:
 		tcpm_log(port, "Unhandled data message type %#x", type);
 		break;
@@ -1432,6 +1480,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
 		break;
 	case PD_CTRL_REJECT:
 	case PD_CTRL_WAIT:
+	case PD_CTRL_NOT_SUPP:
 		switch (port->state) {
 		case SNK_NEGOTIATE_CAPABILITIES:
 			/* USB PD specification, Figure 8-43 */
@@ -1548,12 +1597,84 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
 			break;
 		}
 		break;
+	case PD_CTRL_GET_SOURCE_CAP_EXT:
+	case PD_CTRL_GET_STATUS:
+	case PD_CTRL_FR_SWAP:
+	case PD_CTRL_GET_PPS_STATUS:
+	case PD_CTRL_GET_COUNTRY_CODES:
+		/* Currently not supported */
+		tcpm_queue_message(port, PD_MSG_CTRL_NOT_SUPP);
+		break;
 	default:
 		tcpm_log(port, "Unhandled ctrl message type %#x", type);
 		break;
 	}
 }
 
+static void tcpm_pd_ext_msg_request(struct tcpm_port *port,
+				    const struct pd_message *msg)
+{
+	enum pd_ext_msg_type type = pd_header_type_le(msg->header);
+	unsigned int data_size = pd_ext_header_data_size_le(msg->ext_msg.header);
+	u8 *data;
+
+	if (!(msg->ext_msg.header && PD_EXT_HDR_CHUNKED)) {
+		tcpm_log(port, "Unchunked extended messages unsupported");
+		return;
+	}
+
+	if (data_size > (PD_EXT_MAX_LEGACY_DATA)) {
+		tcpm_log(port, "Chunk handling not yet supported");
+		return;
+	}
+
+	data = kzalloc(data_size, GFP_KERNEL);
+	if (!data) {
+		tcpm_log(port, "Failed to allocate memory for ext msg data");
+		return;
+	}
+	memcpy(data, msg->ext_msg.data, data_size);
+
+	switch (type) {
+	case PD_EXT_STATUS:
+		/*
+		 * If PPS related events raised then get PPS status to clear
+		 * (see USB PD 3.0 Spec, 6.5.2.4)
+		 */
+		if (data[EXT_SDB_EVENT_FLAGS] & EXT_SDB_PPS_EVENTS)
+			tcpm_set_state(port, GET_PPS_STATUS_SEND, 0);
+		else
+			tcpm_set_state(port, ready_state(port), 0);
+		break;
+	case PD_EXT_PPS_STATUS:
+		/*
+		 * For now the PPS status message is used to clear events
+		 * and nothing more.
+		 */
+		tcpm_set_state(port, ready_state(port), 0);
+		break;
+	case PD_EXT_SOURCE_CAP_EXT:
+	case PD_EXT_GET_BATT_CAP:
+	case PD_EXT_GET_BATT_STATUS:
+	case PD_EXT_BATT_CAP:
+	case PD_EXT_GET_MANUFACTURER_INFO:
+	case PD_EXT_MANUFACTURER_INFO:
+	case PD_EXT_SECURITY_REQUEST:
+	case PD_EXT_SECURITY_RESPONSE:
+	case PD_EXT_FW_UPDATE_REQUEST:
+	case PD_EXT_FW_UPDATE_RESPONSE:
+	case PD_EXT_COUNTRY_INFO:
+	case PD_EXT_COUNTRY_CODES:
+		tcpm_queue_message(port, PD_MSG_CTRL_NOT_SUPP);
+		break;
+	default:
+		tcpm_log(port, "Unhandle extended message type %#x", type);
+		break;
+	}
+
+	kfree(data);
+}
+
 static void tcpm_pd_rx_handler(struct work_struct *work)
 {
 	struct pd_rx_event *event = container_of(work,
@@ -1594,7 +1715,9 @@ static void tcpm_pd_rx_handler(struct work_struct *work)
 				 "Data role mismatch, initiating error recovery");
 			tcpm_set_state(port, ERROR_RECOVERY, 0);
 		} else {
-			if (cnt)
+			if (msg->header & PD_HEADER_EXT_HDR)
+				tcpm_pd_ext_msg_request(port, msg);
+			else if (cnt)
 				tcpm_pd_data_request(port, msg);
 			else
 				tcpm_pd_ctrl_request(port, msg);
@@ -1654,6 +1777,9 @@ static bool tcpm_send_queued_message(struct tcpm_port *port)
 		case PD_MSG_CTRL_REJECT:
 			tcpm_pd_send_control(port, PD_CTRL_REJECT);
 			break;
+		case PD_MSG_CTRL_NOT_SUPP:
+			tcpm_pd_send_control(port, PD_CTRL_NOT_SUPP);
+			break;
 		case PD_MSG_DATA_SINK_CAP:
 			tcpm_pd_send_sink_caps(port);
 			break;
@@ -2324,14 +2450,6 @@ static inline enum tcpm_state hard_reset_state(struct tcpm_port *port)
 	return SNK_UNATTACHED;
 }
 
-static inline enum tcpm_state ready_state(struct tcpm_port *port)
-{
-	if (port->pwr_role == TYPEC_SOURCE)
-		return SRC_READY;
-	else
-		return SNK_READY;
-}
-
 static inline enum tcpm_state unattached_state(struct tcpm_port *port)
 {
 	if (port->port_type == TYPEC_PORT_DRP) {
@@ -3032,6 +3150,22 @@ static void run_state_machine(struct tcpm_port *port)
 		/* Always switch to unattached state */
 		tcpm_set_state(port, unattached_state(port), 0);
 		break;
+	case GET_STATUS_SEND:
+		tcpm_pd_send_control(port, PD_CTRL_GET_STATUS);
+		tcpm_set_state(port, GET_STATUS_SEND_TIMEOUT,
+			       PD_T_SENDER_RESPONSE);
+		break;
+	case GET_STATUS_SEND_TIMEOUT:
+		tcpm_set_state(port, ready_state(port), 0);
+		break;
+	case GET_PPS_STATUS_SEND:
+		tcpm_pd_send_control(port, PD_CTRL_GET_PPS_STATUS);
+		tcpm_set_state(port, GET_PPS_STATUS_SEND_TIMEOUT,
+			       PD_T_SENDER_RESPONSE);
+		break;
+	case GET_PPS_STATUS_SEND_TIMEOUT:
+		tcpm_set_state(port, ready_state(port), 0);
+		break;
 	case ERROR_RECOVERY:
 		tcpm_swap_complete(port, -EPROTO);
 		tcpm_pps_complete(port, -EPROTO);
-- 
1.9.1