diff options
author | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-09-22 20:54:53 +0100 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-09-22 21:01:40 +0100 |
commit | ae19ffbadc1b2100285a5b5b3d0a4e0a11390904 (patch) | |
tree | 3c2086ab67398a019089a47ca3f362a4bc6db74f /arch/blackfin/kernel/shadow_console.c | |
parent | 34e84f39a27d059a3e6ec6e8b94aafa702e6f220 (diff) | |
parent | 9173a8ef24a6b1b8031507b35b8ffe5f85a87692 (diff) |
Merge branch 'master' into for-linus
Diffstat (limited to 'arch/blackfin/kernel/shadow_console.c')
-rw-r--r-- | arch/blackfin/kernel/shadow_console.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/shadow_console.c b/arch/blackfin/kernel/shadow_console.c new file mode 100644 index 00000000000..8b8c7107a16 --- /dev/null +++ b/arch/blackfin/kernel/shadow_console.c @@ -0,0 +1,113 @@ +/* + * 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); + +} |