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Commit e8bf5bc7 authored by Ley Foon Tan's avatar Ley Foon Tan
Browse files

nios2: add early printk support 



Signed-off-by: default avatarLey Foon Tan <lftan@altera.com>
parent 96f3a5cc

arch/nios2/Kconfig.debug

+11 −0
Original line number Diff line number Diff line
@@ -14,4 +14,15 @@ config DEBUG_STACK_USAGE 


	  This option will slow down process creation somewhat.



config EARLY_PRINTK

	bool "Activate early kernel debugging"

	default y

	select SERIAL_CORE_CONSOLE

	depends on SERIAL_ALTERA_JTAGUART_CONSOLE || SERIAL_ALTERA_UART_CONSOLE

	help

	  Enable early printk on console

	  This is useful for kernel debugging when your machine crashes very

	  early before the console code is initialized.

	  You should normally say N here, unless you want to debug such a crash.



endmenu

arch/nios2/include/asm/prom.h

0 → 100644
+22 −0
Original line number Diff line number Diff line 
/*

 * Copyright Altera Corporation (C) <2015>. All rights reserved

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.

 */



#ifndef __ASM_NIOS2_PROM_H__

#define __ASM_NIOS2_PROM_H__



extern unsigned long __init of_early_console(void);



#endif

arch/nios2/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -20,5 +20,6 @@ obj-y += syscall_table.o 
obj-y	+= time.o

obj-y	+= traps.o



obj-$(CONFIG_EARLY_PRINTK)		+= early_printk.o

obj-$(CONFIG_MODULES)			+= module.o

obj-$(CONFIG_NIOS2_ALIGNMENT_TRAP)	+= misaligned.o

arch/nios2/kernel/early_printk.c

0 → 100644
+118 −0
Original line number Diff line number Diff line 
/*

 * Early printk for Nios2.

 *

 * Copyright (C) 2015, Altera Corporation

 * Copyright (C) 2010, Tobias Klauser <tklauser@distanz.ch>

 * Copyright (C) 2009, Wind River Systems Inc

 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License. See the file "COPYING" in the main directory of this archive

 * for more details.

 */



#include <linux/console.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/io.h>



#include <asm/prom.h>



static unsigned long base_addr;



#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE)



#define ALTERA_JTAGUART_DATA_REG		0

#define ALTERA_JTAGUART_CONTROL_REG		4

#define ALTERA_JTAGUART_CONTROL_WSPACE_MSK	0xFFFF0000

#define ALTERA_JTAGUART_CONTROL_AC_MSK		0x00000400



#define JUART_GET_CR() \

	__builtin_ldwio((void *)(base_addr + ALTERA_JTAGUART_CONTROL_REG))

#define JUART_SET_CR(v) \

	__builtin_stwio((void *)(base_addr + ALTERA_JTAGUART_CONTROL_REG), v)

#define JUART_SET_TX(v) \

	__builtin_stwio((void *)(base_addr + ALTERA_JTAGUART_DATA_REG), v)



static void early_console_write(struct console *con, const char *s, unsigned n)

{

	unsigned long status;



	while (n-- && *s) {

		while (((status = JUART_GET_CR())

				& ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {

#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)

			if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0)

				return;	/* no connection activity */

#endif

		}

		JUART_SET_TX(*s);

		s++;

	}

}



#elif defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)



#define ALTERA_UART_TXDATA_REG		4

#define ALTERA_UART_STATUS_REG		8

#define ALTERA_UART_STATUS_TRDY		0x0040



#define UART_GET_SR() \

	__builtin_ldwio((void *)(base_addr + ALTERA_UART_STATUS_REG))

#define UART_SET_TX(v) \

	__builtin_stwio((void *)(base_addr + ALTERA_UART_TXDATA_REG), v)



static void early_console_putc(char c)

{

	while (!(UART_GET_SR() & ALTERA_UART_STATUS_TRDY))

		;



	UART_SET_TX(c);

}



static void early_console_write(struct console *con, const char *s, unsigned n)

{

	while (n-- && *s) {

		early_console_putc(*s);

		if (*s == '\n')

			early_console_putc('\r');

		s++;

	}

}



#else

# error Neither SERIAL_ALTERA_JTAGUART_CONSOLE nor SERIAL_ALTERA_UART_CONSOLE \

selected

#endif



static struct console early_console_prom = {

	.name	= "early",

	.write	= early_console_write,

	.flags	= CON_PRINTBUFFER | CON_BOOT,

	.index	= -1

};



void __init setup_early_printk(void)

{

#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE) ||	\

	defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)

	base_addr = of_early_console();

#else

	base_addr = 0;

#endif



	if (!base_addr)

		return;



#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)

	/* Clear activity bit so BYPASS doesn't stall if we've used JTAG for

	 * downloading the kernel. This might cause early data to be lost even

	 * if the JTAG terminal is running.

	 */

	JUART_SET_CR(JUART_GET_CR() | ALTERA_JTAGUART_CONTROL_AC_MSK);

#endif



	early_console = &early_console_prom;

	register_console(early_console);

	pr_info("early_console initialized at 0x%08lx\n", base_addr);

}

arch/nios2/kernel/prom.c

+51 −1
Original line number Diff line number Diff line 
/*

 * Device tree support

 *

 * Copyright (C) 2013 Altera Corporation

 * Copyright (C) 2013, 2015 Altera Corporation

 * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>

 *

 * Based on MIPS support for CONFIG_OF device tree support
@@ -30,6 +30,7 @@ 
#include <linux/of_fdt.h>

#include <linux/io.h>



#include <asm/prom.h>

#include <asm/sections.h>



void __init early_init_dt_add_memory_arch(u64 base, u64 size)
@@ -63,3 +64,52 @@ void __init early_init_devtree(void *params) 


	early_init_dt_scan(params);

}



#ifdef CONFIG_EARLY_PRINTK

static int __init early_init_dt_scan_serial(unsigned long node,

			const char *uname, int depth, void *data)

{

	u64 *addr64 = (u64 *) data;

	const char *p;



	/* only consider serial nodes */

	if (strncmp(uname, "serial", 6) != 0)

		return 0;



	p = of_get_flat_dt_prop(node, "compatible", NULL);

	if (!p)

		return 0;



	/*

	 * We found an altera_jtaguart but it wasn't configured for console, so

	 * skip it.

	 */

#ifndef CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE

	if (strncmp(p, "altr,juart", 10) == 0)

		return 0;

#endif



	/*

	 * Same for altera_uart.

	 */

#ifndef CONFIG_SERIAL_ALTERA_UART_CONSOLE

	if (strncmp(p, "altr,uart", 9) == 0)

		return 0;

#endif



	*addr64 = fdt_translate_address((const void *)initial_boot_params,

		node);



	return *addr64 == OF_BAD_ADDR ? 0 : 1;

}



unsigned long __init of_early_console(void)

{

	u64 base = 0;



	if (of_scan_flat_dt(early_init_dt_scan_serial, &base))

		return (u32)ioremap(base, 32);

	else

		return 0;

}

#endif /* CONFIG_EARLY_PRINTK */