purin: add ns16550 driver

BUG=chrome-os-partner:35807
BRANCH=broadcom-firmware
TEST=booted b0 board. messages printed on console:

coreboot-bcf5dc0-dirty bootblock Mon Feb  9 13:33:55 PST 2015 starting...
Exception handlers installed.

Change-Id: I271ead2f4fe48b809fd311acd5a27a675dce549e
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: ddff8fb170e775a121150fce065410d2925ad18c
Original-Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Original-Change-Id: Ia6e82fa89547d61745c1473f723897dc3c1296ef
Original-Reviewed-on: https://chromium-review.googlesource.com/251301
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/9765
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <edward.ocallaghan@koparo.com>

5 files changed, 151 insertions, 387 deletions

diff --git a/src/soc/broadcom/cygnus/Kconfig b/src/soc/broadcom/cygnus/Kconfig
index 158f61c..2ccc306 100644
--- a/src/soc/broadcom/cygnus/Kconfig
+++ b/src/soc/broadcom/cygnus/Kconfig
@@ -39,4 +39,9 @@ config BOOTBLOCK_CPU_INIT
 	string
 	default "soc/broadcom/cygnus/bootblock.c"
 
+config CONSOLE_SERIAL_UART_ADDRESS
+	hex
+	depends on CONSOLE_SERIAL_UART
+	default 0x18023000
+
 endif
diff --git a/src/soc/broadcom/cygnus/Makefile.inc b/src/soc/broadcom/cygnus/Makefile.inc
index dea6cef..b7012ea 100644
--- a/src/soc/broadcom/cygnus/Makefile.inc
+++ b/src/soc/broadcom/cygnus/Makefile.inc
@@ -1,7 +1,7 @@
 ##
 ## This file is part of the coreboot project.
 ##
-## Copyright 2014 Google Inc.
+## Copyright 2015 Google Inc.
 ##
 ## This program is free software; you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
@@ -22,13 +22,15 @@ bootblock-y += cbmem.c
 bootblock-y += i2c.c
 bootblock-y += timer.c
 bootblock-$(CONFIG_SPI_FLASH) += spi.c
-bootblock-$(CONFIG_CONSOLE_SERIAL) += uart.c
+ifeq ($(CONFIG_BOOTBLOCK_CONSOLE),y)
+bootblock-$(CONFIG_DRIVERS_UART) += ns16550.c
+endif
 
 verstage-y += verstage.c
 verstage-y += i2c.c
 verstage-y += timer.c
 verstage-$(CONFIG_SPI_FLASH) += spi.c
-verstage-$(CONFIG_CONSOLE_SERIAL) += uart.c
+verstage-$(CONFIG_DRIVERS_UART) += ns16550.c
 
 romstage-y += cbmem.c
 romstage-y += i2c.c
@@ -36,13 +38,13 @@ romstage-y += timer.c
 romstage-y += romstage.c
 romstage-y += sdram.c
 romstage-$(CONFIG_SPI_FLASH) += spi.c
-romstage-$(CONFIG_CONSOLE_SERIAL) += uart.c
+romstage-$(CONFIG_DRIVERS_UART) += ns16550.c
 
 ramstage-y += cbmem.c
 ramstage-y += i2c.c
 ramstage-y += timer.c
 ramstage-$(CONFIG_SPI_FLASH) += spi.c
-ramstage-$(CONFIG_CONSOLE_SERIAL) += uart.c
+ramstage-$(CONFIG_DRIVERS_UART) += ns16550.c
 
 CPPFLAGS_common += -Isrc/soc/broadcom/cygnus/include/
 
diff --git a/src/soc/broadcom/cygnus/include/soc/ns16550.h b/src/soc/broadcom/cygnus/include/soc/ns16550.h
index 51cb5b4..12e53c1 100644
--- a/src/soc/broadcom/cygnus/include/soc/ns16550.h
+++ b/src/soc/broadcom/cygnus/include/soc/ns16550.h
@@ -1,81 +1,61 @@
 /*
- * NS16550 Serial Port
- * originally from linux source (arch/powerpc/boot/ns16550.h)
+ * This file is part of the coreboot project.
  *
- * Cleanup and unification
- * (C) 2009 by Detlev Zundel, DENX Software Engineering GmbH
+ * Copyright (C) 2000 Flying Pig Systems
+ * Copyright (C) 2005 Wind River Systems
+ * Copyright (C) 2009 DENX Software Engineering GmbH
+ * Copyright (C) 2015 Google Inc.
  *
- * modified slightly to
- * have addresses as offsets from CONFIG_SYS_ISA_BASE
- * added a few more definitions
- * added prototypes for ns16550.c
- * reduced no of com ports to 2
- * modifications (c) Rob Taylor, Flying Pig Systems. 2000.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
  *
- * added support for port on 64-bit bus
- * by Richard Danter (richard.danter@windriver.com), (C) 2005 Wind River Systems
- */
-
-/*
- * Note that the following macro magic uses the fact that the compiler
- * will not allocate storage for arrays of size 0
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
-#include <linux/types.h>
-
-#if !defined(CONFIG_SYS_NS16550_REG_SIZE) || (CONFIG_SYS_NS16550_REG_SIZE == 0)
-#error "Please define NS16550 registers size."
-#elif defined(CONFIG_SYS_NS16550_MEM32)
-#define UART_REG(x) u32 x
-#elif (CONFIG_SYS_NS16550_REG_SIZE > 0)
-#define UART_REG(x)						   \
-	unsigned char prepad_##x[CONFIG_SYS_NS16550_REG_SIZE - 1]; \
-	unsigned char x;
-#elif (CONFIG_SYS_NS16550_REG_SIZE < 0)
-#define UART_REG(x)							\
-	unsigned char x;						\
-	unsigned char postpad_##x[-CONFIG_SYS_NS16550_REG_SIZE - 1];
-#endif
-
-struct NS16550 {
-	UART_REG(rbr);		/* 0 */
-	UART_REG(ier);		/* 1 */
-	UART_REG(fcr);		/* 2 */
-	UART_REG(lcr);		/* 3 */
-	UART_REG(mcr);		/* 4 */
-	UART_REG(lsr);		/* 5 */
-	UART_REG(msr);		/* 6 */
-	UART_REG(spr);		/* 7 */
-#ifdef CONFIG_SOC_DA8XX
-	UART_REG(reg8);		/* 8 */
-	UART_REG(reg9);		/* 9 */
-	UART_REG(revid1);	/* A */
-	UART_REG(revid2);	/* B */
-	UART_REG(pwr_mgmt);	/* C */
-	UART_REG(mdr1);		/* D */
-#else
-	UART_REG(mdr1);		/* 8 */
-	UART_REG(reg9);		/* 9 */
-	UART_REG(regA);		/* A */
-	UART_REG(regB);		/* B */
-	UART_REG(regC);		/* C */
-	UART_REG(regD);		/* D */
-	UART_REG(regE);		/* E */
-	UART_REG(uasr);		/* F */
-	UART_REG(scr);		/* 10*/
-	UART_REG(ssr);		/* 11*/
-	UART_REG(reg12);	/* 12*/
-	UART_REG(osc_12m_sel);	/* 13*/
-#endif
+#include <stdint.h>
+
+struct ns16550 {
+	union {
+		uint32_t thr;	/* Transmit holding register. */
+		uint32_t rbr;	/* Receive buffer register. */
+		uint32_t dll;	/* Divisor latch lsb. */
+	};
+	union {
+		uint32_t ier;	/* Interrupt enable register. */
+		uint32_t dlm;	/* Divisor latch msb. */
+	};
+	union {
+		uint32_t iir;	/* Interrupt identification register. */
+		uint32_t fcr;	/* FIFO control register. */
+	};
+	uint32_t lcr;		/* 3 */
+	uint32_t mcr;		/* 4 */
+	uint32_t lsr;		/* 5 */
+	uint32_t msr;		/* 6 */
+	uint32_t spr;		/* 7 */
+	uint32_t mdr1;		/* 8 */
+	uint32_t reg9;		/* 9 */
+	uint32_t regA;		/* A */
+	uint32_t regB;		/* B */
+	uint32_t regC;		/* C */
+	uint32_t regD;		/* D */
+	uint32_t regE;		/* E */
+	uint32_t uasr;		/* F */
+	uint32_t scr;		/* 10*/
+	uint32_t ssr;		/* 11*/
+	uint32_t reg12;		/* 12*/
+	uint32_t osc_12m_sel;	/* 13*/
 };
 
-#define thr rbr
-#define iir fcr
-#define dll rbr
-#define dlm ier
-
-typedef struct NS16550 *NS16550_t;
-
 /*
  * These are the definitions for the FIFO Control Register
  */
@@ -163,16 +143,5 @@ typedef struct NS16550 *NS16550_t;
 #define UART_IER_THRI	0x02	/* Enable Transmitter holding register int. */
 #define UART_IER_RDI	0x01	/* Enable receiver data interrupt */
 
-
-#ifdef CONFIG_OMAP1510
-#define OSC_12M_SEL	0x01	/* selects 6.5 * current clk div */
-#endif
-
-/* useful defaults for LCR */
+/* useful defaults for LCR: 8 data, 1 stop, no parity */
 #define UART_LCR_8N1	0x03
-
-void NS16550_init(NS16550_t com_port, int baud_divisor);
-void NS16550_putc(NS16550_t com_port, char c);
-char NS16550_getc(NS16550_t com_port);
-int NS16550_tstc(NS16550_t com_port);
-void NS16550_reinit(NS16550_t com_port, int baud_divisor);
diff --git a/src/soc/broadcom/cygnus/ns16550.c b/src/soc/broadcom/cygnus/ns16550.c
index cbb32e0..d1ef843 100644
--- a/src/soc/broadcom/cygnus/ns16550.c
+++ b/src/soc/broadcom/cygnus/ns16550.c
@@ -1,301 +1,131 @@
 /*
- * (C) Copyright 2000
- * Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
+ * This file is part of the coreboot project.
  *
- * SPDX-License-Identifier:	GPL-2.0+
- */
-
-#include <common.h>
-#include <linux/compiler.h>
-
-#include <ns16550.h>
-#ifdef CONFIG_NS87308
-#include <ns87308.h>
-#endif
-
-#include <serial.h>
-
-#ifndef CONFIG_NS16550_MIN_FUNCTIONS
-
-DECLARE_GLOBAL_DATA_PTR;
-
-#if !defined(CONFIG_CONS_INDEX)
-#elif (CONFIG_CONS_INDEX < 1) || (CONFIG_CONS_INDEX > 6)
-#error	"Invalid console index value."
-#endif
-
-#if CONFIG_CONS_INDEX == 1 && !defined(CONFIG_SYS_NS16550_COM1)
-#error	"Console port 1 defined but not configured."
-#elif CONFIG_CONS_INDEX == 2 && !defined(CONFIG_SYS_NS16550_COM2)
-#error	"Console port 2 defined but not configured."
-#elif CONFIG_CONS_INDEX == 3 && !defined(CONFIG_SYS_NS16550_COM3)
-#error	"Console port 3 defined but not configured."
-#elif CONFIG_CONS_INDEX == 4 && !defined(CONFIG_SYS_NS16550_COM4)
-#error	"Console port 4 defined but not configured."
-#elif CONFIG_CONS_INDEX == 5 && !defined(CONFIG_SYS_NS16550_COM5)
-#error	"Console port 5 defined but not configured."
-#elif CONFIG_CONS_INDEX == 6 && !defined(CONFIG_SYS_NS16550_COM6)
-#error	"Console port 6 defined but not configured."
-#endif
-
-/* Note: The port number specified in the functions is 1 based.
- *	 the array is 0 based.
+ * Copyright (C) 2000 Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
+ * Copyright (C) Broadcom Corporation
+ * Copyright (C) 2015 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  */
-static NS16550_t serial_ports[6] = {
-#ifdef CONFIG_SYS_NS16550_COM1
-	(NS16550_t)CONFIG_SYS_NS16550_COM1,
-#else
-	NULL,
-#endif
-#ifdef CONFIG_SYS_NS16550_COM2
-	(NS16550_t)CONFIG_SYS_NS16550_COM2,
-#else
-	NULL,
-#endif
-#ifdef CONFIG_SYS_NS16550_COM3
-	(NS16550_t)CONFIG_SYS_NS16550_COM3,
-#else
-	NULL,
-#endif
-#ifdef CONFIG_SYS_NS16550_COM4
-	(NS16550_t)CONFIG_SYS_NS16550_COM4,
-#else
-	NULL,
-#endif
-#ifdef CONFIG_SYS_NS16550_COM5
-	(NS16550_t)CONFIG_SYS_NS16550_COM5,
-#else
-	NULL,
-#endif
-#ifdef CONFIG_SYS_NS16550_COM6
-	(NS16550_t)CONFIG_SYS_NS16550_COM6
-#else
-	NULL
-#endif
-};
 
-#define PORT	serial_ports[port-1]
+#include <arch/io.h>
+#include <boot/coreboot_tables.h>
+#include <console/console.h>	/* for __console definition */
+#include <console/uart.h>
+#include <delay.h>
+#include <soc/ns16550.h>
 
-/* Multi serial device functions */
-#define DECLARE_ESERIAL_FUNCTIONS(port) \
-	static int  eserial##port##_init(void) \
-	{ \
-		int clock_divisor; \
-		clock_divisor = calc_divisor(serial_ports[port-1]); \
-		NS16550_init(serial_ports[port-1], clock_divisor); \
-		return 0 ; \
-	} \
-	static void eserial##port##_setbrg(void) \
-	{ \
-		serial_setbrg_dev(port); \
-	} \
-	static int  eserial##port##_getc(void) \
-	{ \
-		return serial_getc_dev(port); \
-	} \
-	static int  eserial##port##_tstc(void) \
-	{ \
-		return serial_tstc_dev(port); \
-	} \
-	static void eserial##port##_putc(const char c) \
-	{ \
-		serial_putc_dev(port, c); \
-	} \
-	static void eserial##port##_puts(const char *s) \
-	{ \
-		serial_puts_dev(port, s); \
-	}
+#define SYS_NS16550_CLK		100000000
+#define SYS_NS16550_BAUDRATE	115200
+#define MODE_X_DIV		16
+#define SINGLE_CHAR_TIMEOUT	(50 * 1000)
 
-/* Serial device descriptor */
-#define INIT_ESERIAL_STRUCTURE(port, __name) {	\
-	.name	= __name,			\
-	.start	= eserial##port##_init,		\
-	.stop	= NULL,				\
-	.setbrg	= eserial##port##_setbrg,	\
-	.getc	= eserial##port##_getc,		\
-	.tstc	= eserial##port##_tstc,		\
-	.putc	= eserial##port##_putc,		\
-	.puts	= eserial##port##_puts,		\
-}
+static struct ns16550 * const regs =
+	(void *)CONFIG_CONSOLE_SERIAL_UART_ADDRESS;
 
-int calc_divisor(NS16550_t port)
+static int calc_divisor(void)
 {
-#ifdef CONFIG_OMAP1510
-	/* If can't cleanly clock 115200 set div to 1 */
-	if ((CONFIG_SYS_NS16550_CLK == 12000000) && (gd->baudrate == 115200)) {
-		port->osc_12m_sel = OSC_12M_SEL;	/* enable 6.5 * divisor */
-		return (1);				/* return 1 for base divisor */
-	}
-	port->osc_12m_sel = 0;			/* clear if previsouly set */
-#endif
-#ifdef CONFIG_OMAP1610
-	/* If can't cleanly clock 115200 set div to 1 */
-	if ((CONFIG_SYS_NS16550_CLK == 48000000) && (gd->baudrate == 115200)) {
-		return (26);		/* return 26 for base divisor */
-	}
-#endif
-
-#define MODE_X_DIV 16
 	/* Compute divisor value. Normally, we should simply return:
-	 *   CONFIG_SYS_NS16550_CLK) / MODE_X_DIV / gd->baudrate
+	 *   ns16550_clk / MODE_X_DIV / baudrate
 	 * but we need to round that value by adding 0.5.
 	 * Rounding is especially important at high baud rates.
 	 */
-	return (CONFIG_SYS_NS16550_CLK + (gd->baudrate * (MODE_X_DIV / 2))) /
-		(MODE_X_DIV * gd->baudrate);
+	int div = MODE_X_DIV * SYS_NS16550_BAUDRATE;
+	return (SYS_NS16550_CLK + div / 2) / div;
 }
 
-void
-_serial_putc(const char c,const int port)
+static void ns16550_init(void)
 {
-	if (c == '\n')
-		NS16550_putc(PORT, '\r');
-
-	NS16550_putc(PORT, c);
-}
-
-void
-_serial_putc_raw(const char c,const int port)
+	int baud_divisor = calc_divisor();
+
+	while (!(readl(&regs->lsr) & UART_LSR_TEMT))
+		;
+
+	writel(0, &regs->ier);
+	writel(UART_LCR_BKSE | UART_LCR_8N1, &regs->lcr);
+	writel(0, &regs->dll);
+	writel(0, &regs->dlm);
+	writel(UART_LCR_8N1, &regs->lcr);
+	writel(UART_MCR_DTR | UART_MCR_RTS, &regs->mcr);
+	/* clear & enable FIFOs */
+	writel(UART_FCR_FIFO_EN | UART_FCR_RXSR | UART_FCR_TXSR, &regs->fcr);
+	writel(UART_LCR_BKSE | UART_LCR_8N1, &regs->lcr);
+	writel(baud_divisor & 0xff, &regs->dll);
+	writel((baud_divisor >> 8) & 0xff, &regs->dlm);
+	writel(UART_LCR_8N1, &regs->lcr);
+}
+
+static void ns16550_tx_byte(unsigned char data)
 {
-	NS16550_putc(PORT, c);
+	while ((readl(&regs->lsr) & UART_LSR_THRE) == 0)
+		;
+	writel(data, &regs->thr);
 }
 
-void
-_serial_puts (const char *s,const int port)
+static void ns16550_tx_flush(void)
 {
-	while (*s) {
-		_serial_putc (*s++,port);
-	}
+	while (!(readl(&regs->lsr) & UART_LSR_TEMT))
+		;
 }
 
-
-int
-_serial_getc(const int port)
+static int ns16550_tst_byte(void)
 {
-	return NS16550_getc(PORT);
+	return (readl(&regs->lsr) & UART_LSR_DR) != 0;
 }
 
-int
-_serial_tstc(const int port)
+static unsigned char ns16550_rx_byte(void)
 {
-	return NS16550_tstc(PORT);
+	unsigned long int i = SINGLE_CHAR_TIMEOUT;
+	while (i-- && !ns16550_tst_byte())
+		udelay(1);
+	if (i)
+		return readl(&regs->rbr);
+	else
+		return 0x0;
 }
 
-void
-_serial_setbrg (const int port)
+void uart_init(int idx)
 {
-	int clock_divisor;
-
-	clock_divisor = calc_divisor(PORT);
-	NS16550_reinit(PORT, clock_divisor);
+	ns16550_init();
 }
 
-static inline void
-serial_putc_dev(unsigned int dev_index,const char c)
+void uart_tx_byte(int idx, unsigned char data)
 {
-	_serial_putc(c,dev_index);
+	ns16550_tx_byte(data);
 }
 
-static inline void
-serial_putc_raw_dev(unsigned int dev_index,const char c)
+void uart_tx_flush(int idx)
 {
-	_serial_putc_raw(c,dev_index);
+	ns16550_tx_flush();
 }
 
-static inline void
-serial_puts_dev(unsigned int dev_index,const char *s)
+unsigned char uart_rx_byte(int idx)
 {
-	_serial_puts(s,dev_index);
+	return ns16550_rx_byte();
 }
 
-static inline int
-serial_getc_dev(unsigned int dev_index)
+#ifndef __PRE_RAM__
+void uart_fill_lb(void *data)
 {
-	return _serial_getc(dev_index);
-}
+	struct lb_serial serial;
+	serial.type = LB_SERIAL_TYPE_MEMORY_MAPPED;
+	serial.baseaddr = (uintptr_t)regs;
+	serial.baud = default_baudrate();
+	serial.regwidth = 1;
+	lb_add_serial(&serial, data);
 
-static inline int
-serial_tstc_dev(unsigned int dev_index)
-{
-	return _serial_tstc(dev_index);
-}
-
-static inline void
-serial_setbrg_dev(unsigned int dev_index)
-{
-	_serial_setbrg(dev_index);
+	lb_add_console(LB_TAG_CONSOLE_SERIAL8250MEM, data);
 }
-
-#if defined(CONFIG_SYS_NS16550_COM1)
-DECLARE_ESERIAL_FUNCTIONS(1);
-struct serial_device eserial1_device =
-	INIT_ESERIAL_STRUCTURE(1, "eserial0");
-#endif
-#if defined(CONFIG_SYS_NS16550_COM2)
-DECLARE_ESERIAL_FUNCTIONS(2);
-struct serial_device eserial2_device =
-	INIT_ESERIAL_STRUCTURE(2, "eserial1");
-#endif
-#if defined(CONFIG_SYS_NS16550_COM3)
-DECLARE_ESERIAL_FUNCTIONS(3);
-struct serial_device eserial3_device =
-	INIT_ESERIAL_STRUCTURE(3, "eserial2");
-#endif
-#if defined(CONFIG_SYS_NS16550_COM4)
-DECLARE_ESERIAL_FUNCTIONS(4);
-struct serial_device eserial4_device =
-	INIT_ESERIAL_STRUCTURE(4, "eserial3");
 #endif
-#if defined(CONFIG_SYS_NS16550_COM5)
-DECLARE_ESERIAL_FUNCTIONS(5);
-struct serial_device eserial5_device =
-	INIT_ESERIAL_STRUCTURE(5, "eserial4");
-#endif
-#if defined(CONFIG_SYS_NS16550_COM6)
-DECLARE_ESERIAL_FUNCTIONS(6);
-struct serial_device eserial6_device =
-	INIT_ESERIAL_STRUCTURE(6, "eserial5");
-#endif
-
-__weak struct serial_device *default_serial_console(void)
-{
-#if CONFIG_CONS_INDEX == 1
-	return &eserial1_device;
-#elif CONFIG_CONS_INDEX == 2
-	return &eserial2_device;
-#elif CONFIG_CONS_INDEX == 3
-	return &eserial3_device;
-#elif CONFIG_CONS_INDEX == 4
-	return &eserial4_device;
-#elif CONFIG_CONS_INDEX == 5
-	return &eserial5_device;
-#elif CONFIG_CONS_INDEX == 6
-	return &eserial6_device;
-#else
-#error "Bad CONFIG_CONS_INDEX."
-#endif
-}
-
-void ns16550_serial_initialize(void)
-{
-#if defined(CONFIG_SYS_NS16550_COM1)
-	serial_register(&eserial1_device);
-#endif
-#if defined(CONFIG_SYS_NS16550_COM2)
-	serial_register(&eserial2_device);
-#endif
-#if defined(CONFIG_SYS_NS16550_COM3)
-	serial_register(&eserial3_device);
-#endif
-#if defined(CONFIG_SYS_NS16550_COM4)
-	serial_register(&eserial4_device);
-#endif
-#if defined(CONFIG_SYS_NS16550_COM5)
-	serial_register(&eserial5_device);
-#endif
-#if defined(CONFIG_SYS_NS16550_COM6)
-	serial_register(&eserial6_device);
-#endif
-}
-
-#endif /* !CONFIG_NS16550_MIN_FUNCTIONS */
diff --git a/src/soc/broadcom/cygnus/uart.c b/src/soc/broadcom/cygnus/uart.c
deleted file mode 100644
index 70b4a2e..0000000
--- a/src/soc/broadcom/cygnus/uart.c
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright 2015 Google Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <boot/coreboot_tables.h>
-#include <console/uart.h>
-
-void uart_init(int idx)
-{
-}
-
-void uart_tx_byte(int idx, unsigned char data)
-{
-}
-
-void uart_tx_flush(int idx)
-{
-}
-
-unsigned char uart_rx_byte(int idx)
-{
-	return '\0';
-}
-
-void uart_fill_lb(void *data)
-{
-}