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>

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)

src/drivers/uart/pl011.h

@@ -0,0 +1,94 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+ * Copyright 2018-present Facebook, Inc.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __DRIVERS_UART_PL011_H
+#define __DRIVERS_UART_PL011_H
+
+#include <inttypes.h>
+#include <types.h>
+
+/* PL011 r1p5 registers */
+struct pl011_uart {
+	u32 dr;
+	u32 rsr_ecr;
+	u8 rsvd1[0x10];
+	u32 fr;
+	u8 rsvd2[0x4];
+	u32 ilpr;
+	u32 ibrd;
+	u32 fbrd;
+	u32 lcr_h;
+	u32 cr;
+	u32 ifls;
+	u32 imsc;
+	u32 ris;
+	u32 mis;
+	u32 icr;
+	u32 dmacr;
+	u8 rsvd3[0xf94];
+	u32 periphid0;
+	u32 periphid1;
+	u32 periphid2;
+	u32 periphid3;
+	u32 cellid0;
+	u32 cellid1;
+	u32 cellid2;
+	u32 cellid3;
+};
+check_member(pl011_uart, cellid3, 0xffc);
+
+/*************************************************************************/
+/* Bit definitions from arm-trusted-firmware/include/drivers/arm/pl011.h */
+/*************************************************************************/
+/* Flag reg bits */
+#define PL011_UARTFR_RI		(1 << 8)	/* Ring indicator */
+#define PL011_UARTFR_TXFE	(1 << 7)	/* Transmit FIFO empty */
+#define PL011_UARTFR_RXFF	(1 << 6)	/* Receive  FIFO full */
+#define PL011_UARTFR_TXFF	(1 << 5)	/* Transmit FIFO full */
+#define PL011_UARTFR_RXFE	(1 << 4)	/* Receive FIFO empty */
+#define PL011_UARTFR_BUSY	(1 << 3)	/* UART busy */
+#define PL011_UARTFR_DCD	(1 << 2)	/* Data carrier detect */
+#define PL011_UARTFR_DSR	(1 << 1)	/* Data set ready */
+#define PL011_UARTFR_CTS	(1 << 0)	/* Clear to send */
+
+#define PL011_UARTFR_TXFF_BIT	5		/* Transmit FIFO full bit in
+						   UARTFR register */
+#define PL011_UARTFR_RXFE_BIT	4		/* Receive FIFO empty bit in
+						   UARTFR register */
+#define PL011_UARTFR_BUSY_BIT	3		/* UART busy bit in UARTFR
+						   register */
+
+/* Control reg bits */
+#define PL011_UARTCR_CTSEN	(1 << 15)	/* CTS hardware flow control
+						   enable */
+#define PL011_UARTCR_RTSEN	(1 << 14)	/* RTS hardware flow control
+						   enable */
+#define PL011_UARTCR_RTS	(1 << 11)	/* Request to send */
+#define PL011_UARTCR_DTR	(1 << 10)	/* Data transmit ready. */
+#define PL011_UARTCR_RXE	(1 << 9)	/* Receive enable */
+#define PL011_UARTCR_TXE	(1 << 8)	/* Transmit enable */
+#define PL011_UARTCR_LBE	(1 << 7)	/* Loopback enable */
+#define PL011_UARTCR_UARTEN	(1 << 0)	/* UART Enable */
+
+/* FIFO Enabled / No Parity / 8 Data bit / One Stop Bit */
+#define PL011_LINE_CONTROL	(PL011_UARTLCR_H_FEN | PL011_UARTLCR_H_WLEN_8)
+
+/* Line Control Register Bits */
+#define PL011_UARTLCR_H_SPS	(1 << 7)	/* Stick parity select */
+#define PL011_UARTLCR_H_WLEN_8	(3 << 5)
+#define PL011_UARTLCR_H_WLEN_7	(2 << 5)
+#define PL011_UARTLCR_H_WLEN_6	(1 << 5)
+#define PL011_UARTLCR_H_WLEN_5	(0 << 5)
+#define PL011_UARTLCR_H_FEN	(1 << 4)	/* FIFOs Enable */
+#define PL011_UARTLCR_H_STP2	(1 << 3)	/* Two stop bits select */
+#define PL011_UARTLCR_H_EPS	(1 << 2)	/* Even parity select */
+#define PL011_UARTLCR_H_PEN	(1 << 1)	/* Parity Enable */
+#define PL011_UARTLCR_H_BRK	(1 << 0)	/* Send break */
+
+#endif				/* ! __DRIVERS_UART_PL011_H */