1 files changed, 92 insertions, 0 deletions
diff --git a/drivers/serial/serial_xtensa_semihosting.c b/drivers/serial/serial_xtensa_semihosting.c
new file mode 100644
index 00000000000..0e59a9bfdc7
--- /dev/null
+++ b/drivers/serial/serial_xtensa_semihosting.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2024 Jiaxun Yang <jiaxun.yang@flygoat.com>
+ */
+
+#include <dm.h>
+#include <malloc.h>
+#include <serial.h>
+
+#include <asm/platform/simcall.h>
+
+/**
+ * struct simc_serial_priv - Semihosting serial private data
+ * @counter: Counter used to fake pending every other call
+ */
+struct simc_serial_priv {
+	unsigned int counter;
+};
+
+static int simc_serial_getc(struct udevice *dev)
+{
+	char ch = 0;
+
+	simc_read(0, &ch, sizeof(ch));
+
+	return ch;
+}
+
+static int simc_serial_putc(struct udevice *dev, const char ch)
+{
+	char str[2] = {0};
+
+	str[0] = ch;
+	simc_write(1, str, 1);
+
+	return 0;
+}
+
+static int simc_serial_pending(struct udevice *dev, bool input)
+{
+	struct simc_serial_priv *priv = dev_get_priv(dev);
+
+	if (input) {
+		int res = simc_poll(0);
+		return res < 0 ? priv->counter++ & 1 : res;
+	}
+
+	return false;
+}
+
+static ssize_t smh_serial_puts(struct udevice *dev, const char *s, size_t len)
+{
+	int ret;
+
+	ret = simc_write(1, s, len);
+
+	return ret;
+}
+
+static const struct dm_serial_ops simc_serial_ops = {
+	.putc = simc_serial_putc,
+	.puts = smh_serial_puts,
+	.getc = simc_serial_getc,
+	.pending = simc_serial_pending,
+};
+
+U_BOOT_DRIVER(simc_serial) = {
+	.name	= "serial_xtensa_semihosting",
+	.id	= UCLASS_SERIAL,
+	.priv_auto = sizeof(struct simc_serial_priv),
+	.ops	= &simc_serial_ops,
+	.flags	= DM_FLAG_PRE_RELOC,
+};
+
+U_BOOT_DRVINFO(simc_serial) = {
+	.name = "serial_xtensa_semihosting",
+};
+
+#if CONFIG_IS_ENABLED(DEBUG_UART_XTENSA_SEMIHOSTING)
+#include <debug_uart.h>
+
+static inline void _debug_uart_init(void)
+{
+}
+
+static inline void _debug_uart_putc(int c)
+{
+	simc_serial_putc(NULL, c);
+}
+
+DEBUG_UART_FUNCS
+#endif