[PATCH] serial: uartlite: Move out-of-range port-numbers into ULITE_NR_UARTS range

Find free uart_port struct in range 0 <= id < ULITE_NR_UARTS when
the device tree port-number property is outside that range. This
can happen because the Xilinx device tree generator does not start
enumerating Uartlites at 0 when there are PS-UARTs or AXI 16550A
UARTs in the system; it then enumerates all UARTs consecutively
despite them having separate drivers with separate structures.
This has become more problematic since the Kconfig property
SERIAL_UARTLITE_NR_UARTS enables precise allocation of uart_port
structs, which can't be used if the port-number doesn't start at 0

Signed-off-by: Ruediger Willenberg <redacted>
---
 drivers/tty/serial/uartlite.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index d3d9566e5dbd..546eecdb6033 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c

@@ -632,14 +632,14 @@ static int ulite_assign(struct device *dev, int id, u32 base, int irq,
 	struct uart_port *port;
 	int rc;
 
-	/* if id = -1; then scan for a free id and use that */
-	if (id < 0) {
+	/* if id -1 or out of range; then scan for a free id and use that */
+	if (id < 0 || id >= ULITE_NR_UARTS) {
 		for (id = 0; id < ULITE_NR_UARTS; id++)
 			if (ulite_ports[id].mapbase == 0)
 				break;
 	}
-	if (id < 0 || id >= ULITE_NR_UARTS) {
-		dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
+	if (id == ULITE_NR_UARTS) {
+		dev_err(dev, "maximum number of %s assigned\n", ULITE_NAME);
 		return -EINVAL;
 	}
 

-- 
2.25.1