111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/*
|
|
* Early printk support for Microblaze.
|
|
*
|
|
* Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
|
|
* Copyright (C) 2007-2009 PetaLogix
|
|
* Copyright (C) 2003-2006 Yasushi SHOJI <yashi@atmark-techno.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/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/string.h>
|
|
#include <linux/tty.h>
|
|
#include <linux/io.h>
|
|
#include <asm/processor.h>
|
|
#include <linux/fcntl.h>
|
|
#include <asm/setup.h>
|
|
#include <asm/prom.h>
|
|
|
|
static u32 early_console_initialized;
|
|
static u32 base_addr;
|
|
|
|
static void early_printk_putc(char c)
|
|
{
|
|
/*
|
|
* Limit how many times we'll spin waiting for TX FIFO status.
|
|
* This will prevent lockups if the base address is incorrectly
|
|
* set, or any other issue on the UARTLITE.
|
|
* This limit is pretty arbitrary, unless we are at about 10 baud
|
|
* we'll never timeout on a working UART.
|
|
*/
|
|
|
|
unsigned retries = 10000;
|
|
/* read status bit - 0x8 offset */
|
|
while (--retries && (in_be32(base_addr + 8) & (1 << 3)))
|
|
;
|
|
|
|
/* Only attempt the iowrite if we didn't timeout */
|
|
/* write to TX_FIFO - 0x4 offset */
|
|
if (retries)
|
|
out_be32(base_addr + 4, c & 0xff);
|
|
}
|
|
|
|
static void early_printk_write(struct console *unused,
|
|
const char *s, unsigned n)
|
|
{
|
|
while (*s && n-- > 0) {
|
|
early_printk_putc(*s);
|
|
if (*s == '\n')
|
|
early_printk_putc('\r');
|
|
s++;
|
|
}
|
|
}
|
|
|
|
static struct console early_serial_console = {
|
|
.name = "earlyser",
|
|
.write = early_printk_write,
|
|
.flags = CON_PRINTBUFFER,
|
|
.index = -1,
|
|
};
|
|
|
|
static struct console *early_console = &early_serial_console;
|
|
|
|
void early_printk(const char *fmt, ...)
|
|
{
|
|
char buf[512];
|
|
int n;
|
|
va_list ap;
|
|
|
|
if (early_console_initialized) {
|
|
va_start(ap, fmt);
|
|
n = vscnprintf(buf, 512, fmt, ap);
|
|
early_console->write(early_console, buf, n);
|
|
va_end(ap);
|
|
}
|
|
}
|
|
|
|
int __init setup_early_printk(char *opt)
|
|
{
|
|
if (early_console_initialized)
|
|
return 1;
|
|
|
|
base_addr = early_uartlite_console();
|
|
if (base_addr) {
|
|
early_console_initialized = 1;
|
|
#ifdef CONFIG_MMU
|
|
early_console_reg_tlb_alloc(base_addr);
|
|
#endif
|
|
early_printk("early_printk_console is enabled at 0x%08x\n",
|
|
base_addr);
|
|
|
|
/* register_console(early_console); */
|
|
|
|
return 0;
|
|
} else
|
|
return 1;
|
|
}
|
|
|
|
void __init disable_early_printk(void)
|
|
{
|
|
if (!early_console_initialized || !early_console)
|
|
return;
|
|
printk(KERN_WARNING "disabling early console\n");
|
|
unregister_console(early_console);
|
|
early_console_initialized = 0;
|
|
}
|