usb: musb: Fix a few off-by-one lengths

commit e87c3f80 upstream.

!strncmp(buf, "force host", 9) is true if and only if buf starts with
"force hos". This was obviously not what was intended. The same error
exists for "force full-speed", "force high-speed" and "test
packet". Using strstarts avoids the error-prone hardcoding of the
prefix length.

For consistency, also change the other occurences of the !strncmp
idiom.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/usb/musb/musb_cppi41.c

@@ -586,9 +586,9 @@ static int cppi41_dma_controller_start(struct cppi41_dma_controller *controller)
 		ret = of_property_read_string_index(np, "dma-names", i, &str);
 		if (ret)
 			goto err;
-		if (!strncmp(str, "tx", 2))
+		if (strstarts(str, "tx"))
 			is_tx = 1;
-		else if (!strncmp(str, "rx", 2))
+		else if (strstarts(str, "rx"))
 			is_tx = 0;
 		else {
 			dev_err(dev, "Wrong dmatype %s\n", str);

drivers/usb/musb/musb_debugfs.c

@@ -194,30 +194,30 @@ static ssize_t musb_test_mode_write(struct file *file,
 	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
 		return -EFAULT;
 
-	if (!strncmp(buf, "force host", 9))
+	if (strstarts(buf, "force host"))
 		test = MUSB_TEST_FORCE_HOST;
 
-	if (!strncmp(buf, "fifo access", 11))
+	if (strstarts(buf, "fifo access"))
 		test = MUSB_TEST_FIFO_ACCESS;
 
-	if (!strncmp(buf, "force full-speed", 15))
+	if (strstarts(buf, "force full-speed"))
 		test = MUSB_TEST_FORCE_FS;
 
-	if (!strncmp(buf, "force high-speed", 15))
+	if (strstarts(buf, "force high-speed"))
 		test = MUSB_TEST_FORCE_HS;
 
-	if (!strncmp(buf, "test packet", 10)) {
+	if (strstarts(buf, "test packet")) {
 		test = MUSB_TEST_PACKET;
 		musb_load_testpacket(musb);
 	}
 
-	if (!strncmp(buf, "test K", 6))
+	if (strstarts(buf, "test K"))
 		test = MUSB_TEST_K;
 
-	if (!strncmp(buf, "test J", 6))
+	if (strstarts(buf, "test J"))
 		test = MUSB_TEST_J;
 
-	if (!strncmp(buf, "test SE0 NAK", 12))
+	if (strstarts(buf, "test SE0 NAK"))
 		test = MUSB_TEST_SE0_NAK;
 
 	musb_writeb(musb->mregs, MUSB_TESTMODE, test);