pfifo.c

linux 内核源代码

/*
 * arch/arm/mach-netx/pfifo.c
 *
 * Copyright (c) 2005 Sascha Hauer <[e-mail]>, Pengutronix
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>

#include <asm/io.h>
#include <asm/hardware.h>
#include <asm/arch/netx-regs.h>
#include <asm/arch/pfifo.h>

static DEFINE_MUTEX(pfifo_lock);

static unsigned int pfifo_used = 0;

int pfifo_request(unsigned int pfifo_mask)
{
	int err = 0;
	unsigned int val;

	mutex_lock(&pfifo_lock);

	if (pfifo_mask & pfifo_used) {
		err = -EBUSY;
		goto out;
	}

	pfifo_used |= pfifo_mask;

	val = readl(NETX_PFIFO_RESET);
	writel(val | pfifo_mask, NETX_PFIFO_RESET);
	writel(val, NETX_PFIFO_RESET);

out:
	mutex_unlock(&pfifo_lock);
	return err;
}

void pfifo_free(unsigned int pfifo_mask)
{
	mutex_lock(&pfifo_lock);
	pfifo_used &= ~pfifo_mask;
	mutex_unlock(&pfifo_lock);
}

EXPORT_SYMBOL(pfifo_push);
EXPORT_SYMBOL(pfifo_pop);
EXPORT_SYMBOL(pfifo_fill_level);
EXPORT_SYMBOL(pfifo_empty);
EXPORT_SYMBOL(pfifo_request);
EXPORT_SYMBOL(pfifo_free);