[media] af9013: reimplement firmware download

Split FW download packages smarter way and bug free. Implementation is
based of Andrea Merello's example he provided for tda18218 driver.
Count remaining FW bytes down in loop instead of division and modulo
combination used earlier.

Thanks to: Andrea Merello <andrea.merello@gmail.com>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Cc: Andrea Merello <andrea.merello@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/af9013.c

@@ -1323,13 +1323,11 @@ static struct dvb_frontend_ops af9013_ops;
 
 static int af9013_download_firmware(struct af9013_state *state)
 {
-	int i, len, packets, remainder, ret;
+	int i, len, remaining, ret;
 	const struct firmware *fw;
-	u16 addr = 0x5100; /* firmware start address */
 	u16 checksum = 0;
 	u8 val;
 	u8 fw_params[4];
-	u8 *data;
 	u8 *fw_file = AF9013_DEFAULT_FIRMWARE;
 
 	msleep(100);
@@ -1373,21 +1371,18 @@ static int af9013_download_firmware(struct af9013_state *state)
 	if (ret)
 		goto error_release;
 
-	#define FW_PACKET_MAX_DATA  16
-
-	packets = fw->size / FW_PACKET_MAX_DATA;
-	remainder = fw->size % FW_PACKET_MAX_DATA;
-	len = FW_PACKET_MAX_DATA;
-	for (i = 0; i <= packets; i++) {
-		if (i == packets)  /* set size of the last packet */
-			len = remainder;
-
-		data = (u8 *)(fw->data + i * FW_PACKET_MAX_DATA);
-		ret = af9013_write_ofsm_regs(state, addr, data, len);
-		addr += FW_PACKET_MAX_DATA;
+	#define FW_ADDR 0x5100 /* firmware start address */
+	#define LEN_MAX 16 /* max packet size */
+	for (remaining = fw->size; remaining > 0; remaining -= LEN_MAX) {
+		len = remaining;
+		if (len > LEN_MAX)
+			len = LEN_MAX;
 
+		ret = af9013_write_ofsm_regs(state,
+			FW_ADDR + fw->size - remaining,
+			(u8 *) &fw->data[fw->size - remaining], len);
 		if (ret) {
-			err("firmware download failed at %d with %d", i, ret);
+			err("firmware download failed:%d", ret);
 			goto error_release;
 		}
 	}