V4L/DVB (6643): xc2028: use best match instead of first partial match during firmware selection

Rather than picking the first video standard firmware that supports any of
the standards that the user has requested, try to select one that supports
as many of them as possible.  This improves the likelihood that the firmware
we select will support the user's desired TV standard.

Signed-off-by: Chris Pascoe <c.pascoe@itee.uq.edu.au>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/tuner-xc2028.c

@@ -377,9 +377,13 @@ static int seek_firmware(struct dvb_frontend *fe, unsigned int type,
 			 v4l2_std_id *id)
 {
 	struct xc2028_data *priv = fe->tuner_priv;
-	int                i;
+	int                 i, best_i = -1, best_nr_matches = 0;
 
-	tuner_dbg("%s called\n", __FUNCTION__);
+	tuner_dbg("%s called, want type=", __FUNCTION__);
+	if (debug) {
+		dump_firm_type(type);
+		printk("(%x), id %016llx.\n", type, (unsigned long long)*id);
+	}
 
 	if (!priv->firm) {
 		tuner_err("Error! firmware not loaded\n");
@@ -397,20 +401,45 @@ static int seek_firmware(struct dvb_frontend *fe, unsigned int type,
 
 	/* Seek for generic video standard match */
 	for (i = 0; i < priv->firm_size; i++) {
-		if ((type == priv->firm[i].type) && (*id & priv->firm[i].id))
-			goto found;
+		v4l2_std_id match_mask;
+		int nr_matches;
+
+		if (type != priv->firm[i].type)
+			continue;
+
+		match_mask = *id & priv->firm[i].id;
+		if (!match_mask)
+			continue;
+
+		if ((*id & match_mask) == *id)
+			goto found; /* Supports all the requested standards */
+
+		nr_matches = hweight64(match_mask);
+		if (nr_matches > best_nr_matches) {
+			best_nr_matches = nr_matches;
+			best_i = i;
+		}
+	}
+
+	if (best_nr_matches > 0) {
+		tuner_dbg("Selecting best matching firmware (%d bits) for "
+			  "type=", best_nr_matches);
+		dump_firm_type(type);
+		printk("(%x), id %016llx:\n", type, (unsigned long long)*id);
+		i = best_i;
+		goto found;
 	}
 
 	/*FIXME: Would make sense to seek for type "hint" match ? */
 
-	i = -EINVAL;
+	i = -ENOENT;
 	goto ret;
 
 found:
 	*id = priv->firm[i].id;
 
 ret:
-	tuner_dbg("%s firmware for type=", (i < 0)? "Can't find": "Found");
+	tuner_dbg("%s firmware for type=", (i < 0) ? "Can't find" : "Found");
 	if (debug) {
 		dump_firm_type(type);
 		printk("(%x), id %016llx.\n", type, (unsigned long long)*id);
@@ -432,8 +461,9 @@ static int load_firmware(struct dvb_frontend *fe, unsigned int type,
 		return pos;
 
 	tuner_info("Loading firmware for type=");
-	dump_firm_type(type);
-	printk("(%x), id %016llx.\n", type, (unsigned long long)*id);
+	dump_firm_type(priv->firm[pos].type);
+	printk("(%x), id %016llx.\n", priv->firm[pos].type,
+	       (unsigned long long)*id);
 
 	p = priv->firm[pos].ptr;
 	endp = p + priv->firm[pos].size;