mirror of https://gitee.com/openkylin/linux.git
114 lines
2.7 KiB
C
114 lines
2.7 KiB
C
/*
|
|
* manage a small early shadow of the log buffer which we can pass between the
|
|
* bootloader so early crash messages are communicated properly and easily
|
|
*
|
|
* Copyright 2009 Analog Devices Inc.
|
|
*
|
|
* Enter bugs at http://blackfin.uclinux.org/
|
|
*
|
|
* Licensed under the GPL-2 or later.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/console.h>
|
|
#include <linux/string.h>
|
|
#include <asm/blackfin.h>
|
|
#include <asm/irq_handler.h>
|
|
#include <asm/early_printk.h>
|
|
|
|
#define SHADOW_CONSOLE_START (0x500)
|
|
#define SHADOW_CONSOLE_END (0x1000)
|
|
#define SHADOW_CONSOLE_MAGIC_LOC (0x4F0)
|
|
#define SHADOW_CONSOLE_MAGIC (0xDEADBEEF)
|
|
|
|
static __initdata char *shadow_console_buffer = (char *)SHADOW_CONSOLE_START;
|
|
|
|
__init void early_shadow_write(struct console *con, const char *s,
|
|
unsigned int n)
|
|
{
|
|
unsigned int i;
|
|
/*
|
|
* save 2 bytes for the double null at the end
|
|
* once we fail on a long line, make sure we don't write a short line afterwards
|
|
*/
|
|
if ((shadow_console_buffer + n) <= (char *)(SHADOW_CONSOLE_END - 2)) {
|
|
/* can't use memcpy - it may not be relocated yet */
|
|
for (i = 0; i <= n; i++)
|
|
shadow_console_buffer[i] = s[i];
|
|
shadow_console_buffer += n;
|
|
shadow_console_buffer[0] = 0;
|
|
shadow_console_buffer[1] = 0;
|
|
} else
|
|
shadow_console_buffer = (char *)SHADOW_CONSOLE_END;
|
|
}
|
|
|
|
static __initdata struct console early_shadow_console = {
|
|
.name = "early_shadow",
|
|
.write = early_shadow_write,
|
|
.flags = CON_BOOT | CON_PRINTBUFFER,
|
|
.index = -1,
|
|
.device = 0,
|
|
};
|
|
|
|
__init int shadow_console_enabled(void)
|
|
{
|
|
return early_shadow_console.flags & CON_ENABLED;
|
|
}
|
|
|
|
__init void mark_shadow_error(void)
|
|
{
|
|
int *loc = (int *)SHADOW_CONSOLE_MAGIC_LOC;
|
|
loc[0] = SHADOW_CONSOLE_MAGIC;
|
|
loc[1] = SHADOW_CONSOLE_START;
|
|
}
|
|
|
|
__init void enable_shadow_console(void)
|
|
{
|
|
if (!shadow_console_enabled()) {
|
|
register_console(&early_shadow_console);
|
|
/* for now, assume things are going to fail */
|
|
mark_shadow_error();
|
|
}
|
|
}
|
|
|
|
static __init int disable_shadow_console(void)
|
|
{
|
|
/*
|
|
* by the time pure_initcall runs, the standard console is enabled,
|
|
* and the early_console is off, so unset the magic numbers
|
|
* unregistering the console is taken care of in common code (See
|
|
* ./kernel/printk:disable_boot_consoles() )
|
|
*/
|
|
int *loc = (int *)SHADOW_CONSOLE_MAGIC_LOC;
|
|
|
|
loc[0] = 0;
|
|
|
|
return 0;
|
|
}
|
|
pure_initcall(disable_shadow_console);
|
|
|
|
/*
|
|
* since we can't use printk, dump numbers (as hex), n = # bits
|
|
*/
|
|
__init void early_shadow_reg(unsigned long reg, unsigned int n)
|
|
{
|
|
/*
|
|
* can't use any "normal" kernel features, since thay
|
|
* may not be relocated to their execute address yet
|
|
*/
|
|
int i;
|
|
char ascii[11] = " 0x";
|
|
|
|
n = n / 4;
|
|
reg = reg << ((8 - n) * 4);
|
|
n += 3;
|
|
|
|
for (i = 3; i <= n ; i++) {
|
|
ascii[i] = hex_asc_lo(reg >> 28);
|
|
reg <<= 4;
|
|
}
|
|
early_shadow_write(NULL, ascii, n);
|
|
|
|
}
|