drivers/uart/pl011: Improve PL011 driver

This adds a struct for registers along with some bits from ATF to
the generic PL011 driver. It also adds a naive implementation of
uart_tx_flush() which was previously stubbed out.

Change-Id: Iee3fc6308cb92ad784e5ff3ac3a6e995d535be65
Signed-off-by: David Hendricks <dhendricks@fb.com>
Reviewed-on: https://review.coreboot.org/23031
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 12 insertions, 7 deletions

diff --git a/src/drivers/uart/pl011.c b/src/drivers/uart/pl011.c
index 709320b288..e690a9afb5 100644
--- a/src/drivers/uart/pl011.c
+++ b/src/drivers/uart/pl011.c
@@ -2,6 +2,7 @@
  * This file is part of the coreboot project.
  *
  * Copyright (C) 2013 Google, Inc.
+ * Copyright 2018-present Facebook, Inc.
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
@@ -13,13 +14,10 @@
  * GNU General Public License for more details.
  */
 
+#include <arch/io.h>
 #include <boot/coreboot_tables.h>
 #include <console/uart.h>
-
-static void pl011_uart_tx_byte(unsigned int *uart_base, unsigned char data)
-{
-	*uart_base = (unsigned int)data;
-}
+#include <drivers/uart/pl011.h>
 
 void uart_init(int idx)
 {
@@ -27,12 +25,19 @@ void uart_init(int idx)
 
 void uart_tx_byte(int idx, unsigned char data)
 {
-	unsigned int *uart_base = uart_platform_baseptr(idx);
-	pl011_uart_tx_byte(uart_base, data);
+	struct pl011_uart *regs = uart_platform_baseptr(idx);
+
+	write8(&regs->dr, data);
+	uart_tx_flush(idx);
 }
 
 void uart_tx_flush(int idx)
 {
+	struct pl011_uart *regs = uart_platform_baseptr(idx);
+
+	/* FIXME: add a timeout */
+	while (!(read32(&regs->fr) & PL011_UARTFR_TXFE))
+		;
 }
 
 unsigned char uart_rx_byte(int idx)