staging: typec: tcpm: Respond to Discover Identity commands

If the lower level driver provided a list of VDOs in its configuration
data, send it to the partner as response to a Discover Identity command
if in device mode (UFP).

Cc: Yueyao Zhu <yueyao.zhu@gmail.com>
Originally-from: Puma Hsu <puma_hsu@htc.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/typec/pd_vdo.h

@@ -22,6 +22,9 @@
  * VDM object is minimum of VDM header + 6 additional data objects.
  */
 
+#define VDO_MAX_OBJECTS		6
+#define VDO_MAX_SIZE		(VDO_MAX_OBJECTS + 1)
+
 /*
  * VDM header
  * ----------
@@ -34,7 +37,6 @@
  * <5>      :: reserved (SVDM), command type (UVDM)
  * <4:0>    :: command
  */
-#define VDO_MAX_SIZE 7
 #define VDO(vid, type, custom)				\
 	(((vid) << 16) |				\
 	 ((type) << 15) |				\

drivers/staging/typec/tcpm.c

@@ -252,6 +252,8 @@ struct tcpm_port {
 	unsigned int nr_src_pdo;
 	u32 snk_pdo[PDO_MAX_OBJECTS];
 	unsigned int nr_snk_pdo;
+	u32 snk_vdo[VDO_MAX_OBJECTS];
+	unsigned int nr_snk_vdo;
 
 	unsigned int max_snk_mv;
 	unsigned int max_snk_ma;
@@ -998,6 +1000,7 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 	struct pd_mode_data *modep;
 	int rlen = 0;
 	u16 svid;
+	int i;
 
 	tcpm_log(port, "Rx VDM cmd 0x%x type %d cmd %d len %d",
 		 p0, cmd_type, cmd, cnt);
@@ -1008,6 +1011,14 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 	case CMDT_INIT:
 		switch (cmd) {
 		case CMD_DISCOVER_IDENT:
+			/* 6.4.4.3.1: Only respond as UFP (device) */
+			if (port->data_role == TYPEC_DEVICE &&
+			    port->nr_snk_vdo) {
+				for (i = 0; i <  port->nr_snk_vdo; i++)
+					response[i + 1]
+						= cpu_to_le32(port->snk_vdo[i]);
+				rlen = port->nr_snk_vdo + 1;
+			}
 			break;
 		case CMD_DISCOVER_SVID:
 			break;
@@ -3320,6 +3331,20 @@ static int tcpm_copy_pdos(u32 *dest_pdo, const u32 *src_pdo,
 	return nr_pdo;
 }
 
+static int tcpm_copy_vdos(u32 *dest_vdo, const u32 *src_vdo,
+			  unsigned int nr_vdo)
+{
+	unsigned int i;
+
+	if (nr_vdo > VDO_MAX_OBJECTS)
+		nr_vdo = VDO_MAX_OBJECTS;
+
+	for (i = 0; i < nr_vdo; i++)
+		dest_vdo[i] = src_vdo[i];
+
+	return nr_vdo;
+}
+
 void tcpm_update_source_capabilities(struct tcpm_port *port, const u32 *pdo,
 				     unsigned int nr_pdo)
 {
@@ -3410,6 +3435,8 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 					  tcpc->config->nr_src_pdo);
 	port->nr_snk_pdo = tcpm_copy_pdos(port->snk_pdo, tcpc->config->snk_pdo,
 					  tcpc->config->nr_snk_pdo);
+	port->nr_snk_vdo = tcpm_copy_vdos(port->snk_vdo, tcpc->config->snk_vdo,
+					  tcpc->config->nr_snk_vdo);
 
 	port->max_snk_mv = tcpc->config->max_snk_mv;
 	port->max_snk_ma = tcpc->config->max_snk_ma;

drivers/staging/typec/tcpm.h

@@ -60,6 +60,9 @@ struct tcpc_config {
 	const u32 *snk_pdo;
 	unsigned int nr_snk_pdo;
 
+	const u32 *snk_vdo;
+	unsigned int nr_snk_vdo;
+
 	unsigned int max_snk_mv;
 	unsigned int max_snk_ma;
 	unsigned int max_snk_mw;