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

nios2: add early printk support

Signed-off-by: default avatarLey Foon Tan <lftan@altera.com>
parent 96f3a5cc
......@@ -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
/*
* 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
......@@ -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
/*
* 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);
}
/*
* 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 */
......@@ -139,6 +139,10 @@ void __init setup_arch(char **cmdline_p)
console_verbose();
#ifdef CONFIG_EARLY_PRINTK
setup_early_printk();
#endif
memory_start = PAGE_ALIGN((unsigned long)__pa(_end));
memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size;
......
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