lib: utils: Add simple FDT serial framework

We add simple serial framework which will select and use serial driver
based on details in FDT passed by previous booting stage.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

lib/utils/serial/fdt_serial_uart8250.c

@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/serial/fdt_serial.h>
+#include <sbi_utils/serial/uart8250.h>
+
+static int serial_uart8250_init(void *fdt, int nodeoff,
+				const struct fdt_match *match)
+{
+	int rc;
+	struct platform_uart_data uart;
+
+	rc = fdt_parse_uart8250_node(fdt, nodeoff, &uart);
+	if (rc)
+		return rc;
+
+	return uart8250_init(uart.addr, uart.freq, uart.baud,
+			     uart.reg_shift, uart.reg_io_width);
+}
+
+static const struct fdt_match serial_uart8250_match[] = {
+	{ .compatible = "ns16550" },
+	{ .compatible = "ns16550a" },
+	{ },
+};
+
+struct fdt_serial fdt_serial_uart8250 = {
+	.match_table = serial_uart8250_match,
+	.init = serial_uart8250_init,
+	.getc = uart8250_getc,
+	.putc = uart8250_putc
+};