Add ESP32C3 RISC-V stub
diff --git a/src/kernel/riscv32/serial-esp32c3.c b/src/kernel/riscv32/serial-esp32c3.c
new file mode 100644
index 0000000..32b8178
--- /dev/null
+++ b/src/kernel/riscv32/serial-esp32c3.c
@@ -0,0 +1,32 @@
+#include "serial.h"
+#include "kint.h"
+
+extern int uart_tx_one_char(char byte);
+
+/**
+ * @param c Pointer to input
+ * @returns OK or not
+ */
+extern bool uart_rx_one_char(char *c);
+
+/**
+ * @param uart_no UART number
+ */
+extern void uart_tx_flush(uchar uart_no);
+
+void init_serial()
+{
+}
+
+void serial_put(char byte)
+{
+ uart_tx_one_char(byte);
+}
+
+void serial_write(char *string)
+{
+ while (*string)
+ {
+ serial_put(*string++);
+ }
+}