Blackfin: add an early shadow console (3f871fea) · Commits · 戴 / test

arch/blackfin/include/asm/early_printk.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -23,6 +23,8 @@

		#ifdef CONFIG_EARLY_PRINTK
		extern int setup_early_printk(char *);
		extern void enable_shadow_console(void);
		#else
		#define setup_early_printk(fmt) do { } while (0)
		#define enable_shadow_console(fmt) do { } while (0)
		#endif /* CONFIG_EARLY_PRINTK */

arch/blackfin/kernel/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -26,6 +26,7 @@ obj-$(CONFIG_MODULES) += module.o
		obj-$(CONFIG_KGDB) += kgdb.o
		obj-$(CONFIG_KGDB_TESTS) += kgdb_test.o
		obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
		obj-$(CONFIG_EARLY_PRINTK) += shadow_console.o
		obj-$(CONFIG_STACKTRACE) += stacktrace.o

		# the kgdb test puts code into L2 and without linker

arch/blackfin/kernel/setup.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -810,6 +810,8 @@ void __init setup_arch(char **cmdline_p)
		{
		unsigned long sclk, cclk;

		enable_shadow_console();

		/* Check to make sure we are running on the right processor */
		if (unlikely(CPUID != bfin_cpuid()))
		printk(KERN_ERR "ERROR: Not running on ADSP-%s: unknown CPUID 0x%04x Rev 0.%d\n",

arch/blackfin/kernel/shadow_console.c

0 → 100644

+78 −0

Original line number	Diff line number	Diff line
		/*
		* 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;

		static __init void early_shadow_write(struct console con, const char s,
		unsigned int n)
		{
		/*
		* 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)) {
		memcpy(shadow_console_buffer, s, n);
		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 void enable_shadow_console(void)
		{
		int loc = (int )SHADOW_CONSOLE_MAGIC_LOC;

		if (!(early_shadow_console.flags & CON_ENABLED)) {
		register_console(&early_shadow_console);
		/* for now, assume things are going to fail */
		*loc = SHADOW_CONSOLE_MAGIC;
		loc++;
		*loc = SHADOW_CONSOLE_START;
		}
		}

		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;

		return 0;
		}
		pure_initcall(disable_shadow_console);

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