1 files changed, 111 insertions, 0 deletions
diff --git a/roms/opensbi/lib/utils/serial/fdt_serial.c b/roms/opensbi/lib/utils/serial/fdt_serial.c
new file mode 100644
index 000000000..b9ce67ef1
--- /dev/null
+++ b/roms/opensbi/lib/utils/serial/fdt_serial.c
@@ -0,0 +1,111 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <libfdt.h>
+#include <sbi/sbi_scratch.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/serial/fdt_serial.h>
+
+extern struct fdt_serial fdt_serial_uart8250;
+extern struct fdt_serial fdt_serial_sifive;
+extern struct fdt_serial fdt_serial_htif;
+extern struct fdt_serial fdt_serial_shakti;
+
+static struct fdt_serial *serial_drivers[] = {
+	&fdt_serial_uart8250,
+	&fdt_serial_sifive,
+	&fdt_serial_htif,
+	&fdt_serial_shakti,
+};
+
+static void dummy_putc(char ch)
+{
+}
+
+static int dummy_getc(void)
+{
+	return -1;
+}
+
+static struct fdt_serial dummy = {
+	.match_table = NULL,
+	.init = NULL,
+	.putc = dummy_putc,
+	.getc = dummy_getc,
+};
+
+static struct fdt_serial *current_driver = &dummy;
+
+void fdt_serial_putc(char ch)
+{
+	current_driver->putc(ch);
+}
+
+int fdt_serial_getc(void)
+{
+	return current_driver->getc();
+}
+
+int fdt_serial_init(void)
+{
+	const void *prop;
+	struct fdt_serial *drv;
+	const struct fdt_match *match;
+	int pos, noff = -1, len, coff, rc;
+	void *fdt = sbi_scratch_thishart_arg1_ptr();
+
+	/* Find offset of node pointed by stdout-path */
+	coff = fdt_path_offset(fdt, "/chosen");
+	if (-1 < coff) {
+		prop = fdt_getprop(fdt, coff, "stdout-path", &len);
+		if (prop && len)
+			noff = fdt_path_offset(fdt, prop);
+	}
+
+	/* First check DT node pointed by stdout-path */
+	for (pos = 0; pos < array_size(serial_drivers) && -1 < noff; pos++) {
+		drv = serial_drivers[pos];
+
+		match = fdt_match_node(fdt, noff, drv->match_table);
+		if (!match)
+			continue;
+
+		if (drv->init) {
+			rc = drv->init(fdt, noff, match);
+			if (rc)
+				return rc;
+		}
+		current_driver = drv;
+		break;
+	}
+
+	/* Check if we found desired driver */
+	if (current_driver != &dummy)
+		goto done;
+
+	/* Lastly check all DT nodes */
+	for (pos = 0; pos < array_size(serial_drivers); pos++) {
+		drv = serial_drivers[pos];
+
+		noff = fdt_find_match(fdt, -1, drv->match_table, &match);
+		if (noff < 0)
+			continue;
+
+		if (drv->init) {
+			rc = drv->init(fdt, noff, match);
+			if (rc)
+				return rc;
+		}
+		current_driver = drv;
+		break;
+	}
+
+done:
+	return 0;
+}