[PATCH] ppc64: add a minimal nvram driver

/*

 * NVRAM for CPBW

 *

 * (C) Copyright IBM Corp. 2005

 *

 * Authors : Utz Bacher <utz.bacher@de.ibm.com>

 *

 * 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, 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., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/spinlock.h>

#include <linux/types.h>

#include <asm/machdep.h>

#include <asm/nvram.h>

#include <asm/prom.h>

static void __iomem *bpa_nvram_start;

static long bpa_nvram_len;

static spinlock_t bpa_nvram_lock = SPIN_LOCK_UNLOCKED;

static ssize_t bpa_nvram_read(char *buf, size_t count, loff_t *index)

{

	unsigned long flags;

	if (*index >= bpa_nvram_len)

		return 0;

	if (*index + count > bpa_nvram_len)

		count = bpa_nvram_len - *index;

	spin_lock_irqsave(&bpa_nvram_lock, flags);

	memcpy_fromio(buf, bpa_nvram_start + *index, count);

	spin_unlock_irqrestore(&bpa_nvram_lock, flags);

	*index += count;

	return count;

}

static ssize_t bpa_nvram_write(char *buf, size_t count, loff_t *index)

{

	unsigned long flags;

	if (*index >= bpa_nvram_len)

		return 0;

	if (*index + count > bpa_nvram_len)

		count = bpa_nvram_len - *index;

	spin_lock_irqsave(&bpa_nvram_lock, flags);

	memcpy_toio(bpa_nvram_start + *index, buf, count);

	spin_unlock_irqrestore(&bpa_nvram_lock, flags);

	*index += count;

	return count;

}

static ssize_t bpa_nvram_get_size(void)

{

	return bpa_nvram_len;

}

int __init bpa_nvram_init(void)

{

	struct device_node *nvram_node;

	unsigned long *buffer;

	int proplen;

	unsigned long nvram_addr;

	int ret;

	ret = -ENODEV;

	nvram_node = of_find_node_by_type(NULL, "nvram");

	if (!nvram_node)

		goto out;

	ret = -EIO;

	buffer = (unsigned long *)get_property(nvram_node, "reg", &proplen);

	if (proplen != 2*sizeof(unsigned long))

		goto out;

	ret = -ENODEV;

	nvram_addr = buffer[0];

	bpa_nvram_len = buffer[1];

	if ( (!bpa_nvram_len) || (!nvram_addr) )

		goto out;

	bpa_nvram_start = ioremap(nvram_addr, bpa_nvram_len);

	if (!bpa_nvram_start)

		goto out;

	printk(KERN_INFO "BPA NVRAM, %luk mapped to %p\n",

	       bpa_nvram_len >> 10, bpa_nvram_start);

	ppc_md.nvram_read	= bpa_nvram_read;

	ppc_md.nvram_write	= bpa_nvram_write;

	ppc_md.nvram_size	= bpa_nvram_get_size;

out:

	of_node_put(nvram_node);

	return ret;

}

extern int pSeries_nvram_init(void);

extern int pmac_nvram_init(void);

extern int bpa_nvram_init(void);

/* PowerMac specific nvram stuffs */