amlogic-aml8726-mx-kernel/arch/arm/kernel/fiq_printk.c

/*
 * arch/arm/kernel/fiq_printk.c
 *
 * Copyright (C) 2011-2012 Amlogic, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/nmi.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/smp.h>
#include <linux/security.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/kexec.h>
#include <linux/ratelimit.h>
#include <linux/kmsg_dump.h>
#include <linux/syslog.h>
#include <linux/timer.h>

#include <asm/uaccess.h>

#define MAX_PRINT_SIZE 1024
#define FIQ_PREF "<FIQ>:"

static unsigned char fiqprint_buf[MAX_PRINT_SIZE+4];
static unsigned char fiqprint_buf1[MAX_PRINT_SIZE+4];

static int fiqprint_buf_off=0;

static struct timer_list fiq_print_timer;

/* Must call in FIQ mode */
int fiq_vprintk(const char *fmt, va_list args)
{
	int r;
	char *bufptr = fiqprint_buf + fiqprint_buf_off;
	int buflen = MAX_PRINT_SIZE - fiqprint_buf_off;

	if (buflen > sizeof(FIQ_PREF) + 16) {
		strcpy(bufptr, FIQ_PREF);
		bufptr += strlen(FIQ_PREF);
		buflen -= strlen(FIQ_PREF);
	}

	r = vscnprintf(bufptr, MAX_PRINT_SIZE - fiqprint_buf_off, fmt, args);
	fiqprint_buf_off += r;

	if (fiqprint_buf_off > MAX_PRINT_SIZE)
		fiqprint_buf_off = 0;	// Overflow, drop all

	return r;
}
EXPORT_SYMBOL(fiq_vprintk);

int fiq_printk(const char *fmt, ...)
{
	int r;
	va_list args;

	va_start(args, fmt);
	r = fiq_vprintk(fmt, args);
	va_end(args);

	return r;
}
EXPORT_SYMBOL(fiq_printk);

static void fiq_printk_timer(unsigned long arg)
{
	unsigned long flags;
	int len = 0;

	if (fiqprint_buf_off > 0) {
		raw_local_save_flags(flags);
		local_fiq_disable();
		memcpy(fiqprint_buf1, fiqprint_buf, fiqprint_buf_off);
		len = fiqprint_buf_off;
		fiqprint_buf_off = 0;
		fiqprint_buf1[len] = '\n';
		fiqprint_buf1[len + 1] = '0';
		raw_local_irq_restore(flags);
	}

	if (len > 0)
		printk("%s\n", fiqprint_buf1);

	mod_timer(&fiq_print_timer,jiffies + HZ / 10);
}

static __init int fiq_printk_init(void)
{
	init_timer(&fiq_print_timer);
	fiq_print_timer.function = fiq_printk_timer;
	fiq_print_timer.expires = jiffies + 1;
	fiq_print_timer.data = 0;
	add_timer(&fiq_print_timer);
	return 0;
}
module_init(fiq_printk_init);