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/*
* 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
static void early_console_write(struct console *con, const char *s, unsigned n)
{
}
#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);
}
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