usb: typec: tcpm: pdo matching optimization

This patch is a combination of commit 57e6f0d7
("typec: tcpm: Only request matching pdos") and source
pdo selection optimization based on it, instead of only
compare between the same pdo type of sink and source,
we should check source pdo voltage range is within the
voltage range of one sink pdo.
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Li Jun <jun.li@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/tcpm.c

@@ -1772,39 +1772,63 @@ static int tcpm_pd_check_request(struct tcpm_port *port)
 	return 0;
 }
 
-static int tcpm_pd_select_pdo(struct tcpm_port *port)
+#define min_power(x, y) min(pdo_max_power(x), pdo_max_power(y))
+#define min_current(x, y) min(pdo_max_current(x), pdo_max_current(y))
+
+static int tcpm_pd_select_pdo(struct tcpm_port *port, int *sink_pdo,
+			      int *src_pdo)
 {
-	unsigned int i, max_mw = 0, max_mv = 0;
+	unsigned int i, j, max_src_mv = 0, min_src_mv = 0, max_mw = 0,
+		     max_mv = 0, src_mw = 0, src_ma = 0, max_snk_mv = 0,
+		     min_snk_mv = 0;
 	int ret = -EINVAL;
 
 	/*
-	 * Select the source PDO providing the most power while staying within
-	 * the board's voltage limits. Prefer PDO providing exp
+	 * Select the source PDO providing the most power which has a
+	 * matchig sink cap.
 	 */
 	for (i = 0; i < port->nr_source_caps; i++) {
 		u32 pdo = port->source_caps[i];
 		enum pd_pdo_type type = pdo_type(pdo);
-		unsigned int mv, ma, mw;
 
-		if (type == PDO_TYPE_FIXED)
-			mv = pdo_fixed_voltage(pdo);
-		else
-			mv = pdo_min_voltage(pdo);
+		if (type == PDO_TYPE_FIXED) {
+			max_src_mv = pdo_fixed_voltage(pdo);
+			min_src_mv = max_src_mv;
+		} else {
+			max_src_mv = pdo_max_voltage(pdo);
+			min_src_mv = pdo_min_voltage(pdo);
+		}
 
 		if (type == PDO_TYPE_BATT) {
-			mw = pdo_max_power(pdo);
+			src_mw = pdo_max_power(pdo);
 		} else {
-			ma = min(pdo_max_current(pdo),
-				 port->max_snk_ma);
-			mw = ma * mv / 1000;
+			src_ma = pdo_max_current(pdo);
+			src_mw = src_ma * min_src_mv / 1000;
 		}
 
-		/* Perfer higher voltages if available */
-		if ((mw > max_mw || (mw == max_mw && mv > max_mv)) &&
-		    mv <= port->max_snk_mv) {
-			ret = i;
-			max_mw = mw;
-			max_mv = mv;
+		for (j = 0; j < port->nr_snk_pdo; j++) {
+			pdo = port->snk_pdo[j];
+
+			if (pdo_type(pdo) == PDO_TYPE_FIXED) {
+				min_snk_mv = pdo_fixed_voltage(pdo);
+				max_snk_mv = pdo_fixed_voltage(pdo);
+			} else {
+				min_snk_mv = pdo_min_voltage(pdo);
+				max_snk_mv = pdo_max_voltage(pdo);
+			}
+
+			if (max_src_mv <= max_snk_mv &&
+				min_src_mv >= min_snk_mv) {
+				/* Prefer higher voltages if available */
+				if ((src_mw == max_mw && min_src_mv > max_mv) ||
+							src_mw > max_mw) {
+					*src_pdo = i;
+					*sink_pdo = j;
+					max_mw = src_mw;
+					max_mv = min_src_mv;
+					ret = 0;
+				}
+			}
 		}
 	}
 
@@ -1816,13 +1840,16 @@ static int tcpm_pd_build_request(struct tcpm_port *port, u32 *rdo)
 	unsigned int mv, ma, mw, flags;
 	unsigned int max_ma, max_mw;
 	enum pd_pdo_type type;
-	int index;
-	u32 pdo;
+	int src_pdo_index, snk_pdo_index;
+	u32 pdo, matching_snk_pdo;
+	int ret;
 
-	index = tcpm_pd_select_pdo(port);
-	if (index < 0)
-		return -EINVAL;
-	pdo = port->source_caps[index];
+	ret = tcpm_pd_select_pdo(port, &snk_pdo_index, &src_pdo_index);
+	if (ret < 0)
+		return ret;
+
+	pdo = port->source_caps[src_pdo_index];
+	matching_snk_pdo = port->snk_pdo[snk_pdo_index];
 	type = pdo_type(pdo);
 
 	if (type == PDO_TYPE_FIXED)
@@ -1830,26 +1857,28 @@ static int tcpm_pd_build_request(struct tcpm_port *port, u32 *rdo)
 	else
 		mv = pdo_min_voltage(pdo);
 
-	/* Select maximum available current within the board's power limit */
+	/* Select maximum available current within the sink pdo's limit */
 	if (type == PDO_TYPE_BATT) {
-		mw = pdo_max_power(pdo);
-		ma = 1000 * min(mw, port->max_snk_mw) / mv;
+		mw = min_power(pdo, matching_snk_pdo);
+		ma = 1000 * mw / mv;
 	} else {
-		ma = min(pdo_max_current(pdo),
-			 1000 * port->max_snk_mw / mv);
+		ma = min_current(pdo, matching_snk_pdo);
+		mw = ma * mv / 1000;
 	}
-	ma = min(ma, port->max_snk_ma);
 
 	flags = RDO_USB_COMM | RDO_NO_SUSPEND;
 
 	/* Set mismatch bit if offered power is less than operating power */
-	mw = ma * mv / 1000;
 	max_ma = ma;
 	max_mw = mw;
 	if (mw < port->operating_snk_mw) {
 		flags |= RDO_CAP_MISMATCH;
-		max_mw = port->operating_snk_mw;
-		max_ma = max_mw * 1000 / mv;
+		if (type == PDO_TYPE_BATT &&
+		    (pdo_max_power(matching_snk_pdo) > pdo_max_power(pdo)))
+			max_mw = pdo_max_power(matching_snk_pdo);
+		else if (pdo_max_current(matching_snk_pdo) >
+			 pdo_max_current(pdo))
+			max_ma = pdo_max_current(matching_snk_pdo);
 	}
 
 	tcpm_log(port, "cc=%d cc1=%d cc2=%d vbus=%d vconn=%s polarity=%d",
@@ -1858,16 +1887,16 @@ static int tcpm_pd_build_request(struct tcpm_port *port, u32 *rdo)
 		 port->polarity);
 
 	if (type == PDO_TYPE_BATT) {
-		*rdo = RDO_BATT(index + 1, mw, max_mw, flags);
+		*rdo = RDO_BATT(src_pdo_index + 1, mw, max_mw, flags);
 
 		tcpm_log(port, "Requesting PDO %d: %u mV, %u mW%s",
-			 index, mv, mw,
+			 src_pdo_index, mv, mw,
 			 flags & RDO_CAP_MISMATCH ? " [mismatch]" : "");
 	} else {
-		*rdo = RDO_FIXED(index + 1, ma, max_ma, flags);
+		*rdo = RDO_FIXED(src_pdo_index + 1, ma, max_ma, flags);
 
 		tcpm_log(port, "Requesting PDO %d: %u mV, %u mA%s",
-			 index, mv, ma,
+			 src_pdo_index, mv, ma,
 			 flags & RDO_CAP_MISMATCH ? " [mismatch]" : "");
 	}