1 files changed, 82 insertions, 0 deletions
diff --git a/libgloss/or1k/or1k_uart.c b/libgloss/or1k/or1k_uart.c
new file mode 100644
index 000000000..3d79f4516
--- /dev/null
+++ b/libgloss/or1k/or1k_uart.c
@@ -0,0 +1,82 @@
+/* or1k_uart.c -- UART implementation for OpenRISC 1000.
+ *
+ *Copyright (c) 2014 Authors
+ *
+ * Contributor Stefan Wallentowitz <stefan.wallentowitz@tum.de>
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ */
+
+#include "include/or1k-support.h"
+#include "or1k_uart.h"
+
+#include <stdint.h>
+
+void (*_or1k_uart_read_cb)(char c);
+
+void _or1k_uart_interrupt_handler(uint32_t data)
+{
+	_or1k_uart_read_cb(REG8(RB));
+}
+
+int _or1k_uart_init(void)
+{
+	uint16_t divisor;
+
+	// Is uart present?
+	if (!_or1k_board_uart_base) {
+			return -1;
+	}
+
+	// Reset the callback function
+	_or1k_uart_read_cb = 0;
+
+	// Calculate and set divisor
+	divisor = _or1k_board_clk_freq / (_or1k_board_uart_baud * 16);
+	REG8(LCR) = LCR_DLA;
+	REG8(DLB1) = divisor & 0xff;
+	REG8(DLB2) = divisor >> 8;
+
+	// Set line control register:
+	//  - 8 bits per character
+	//  - 1 stop bit
+	//  - No parity
+	//  - Break disabled
+	//  - Disallow access to divisor latch
+	REG8(LCR) = LCR_BPC_8;
+
+	// Reset FIFOs and set trigger level to 14 bytes
+	REG8(FCR) = FCR_CLRRECV | FCR_CLRTMIT | FCR_TRIG_14;
+
+	// Disable all interrupts
+	REG8(IER) = 0;
+
+	return 0;
+}
+
+void _or1k_uart_write(char c)
+{
+	while (!REG8(LSR) & LSR_TFE) {}
+
+	REG8(THR) = c;
+}
+
+void or1k_uart_set_read_cb(void (*cb)(char c))
+{
+	_or1k_uart_read_cb = cb;
+
+	// Enable interrupt
+	REG8(IER) = 1 << IER_RDAI;
+
+	or1k_interrupt_handler_add(_or1k_board_uart_IRQ,
+			_or1k_uart_interrupt_handler, 0);
+	or1k_interrupt_enable(_or1k_board_uart_IRQ);
+}