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/*
* memory mapped NVRAM
*
* (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 *mmio_nvram_start;
static long mmio_nvram_len;
static DEFINE_SPINLOCK(mmio_nvram_lock);
static ssize_t mmio_nvram_read(char *buf, size_t count, loff_t *index)
{
unsigned long flags;
if (*index >= mmio_nvram_len)
return 0;
if (*index + count > mmio_nvram_len)
count = mmio_nvram_len - *index;
spin_lock_irqsave(&mmio_nvram_lock, flags);
memcpy_fromio(buf, mmio_nvram_start + *index, count);
spin_unlock_irqrestore(&mmio_nvram_lock, flags);
*index += count;
return count;
}
static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index)
{
unsigned long flags;
if (*index >= mmio_nvram_len)
return 0;
if (*index + count > mmio_nvram_len)
count = mmio_nvram_len - *index;
spin_lock_irqsave(&mmio_nvram_lock, flags);
memcpy_toio(mmio_nvram_start + *index, buf, count);
spin_unlock_irqrestore(&mmio_nvram_lock, flags);
*index += count;
return count;
}
static ssize_t mmio_nvram_get_size(void)
{
return mmio_nvram_len;
}
int __init mmio_nvram_init(void)
{
struct device_node *nvram_node;
const 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 = get_property(nvram_node, "reg", &proplen);
if (proplen != 2*sizeof(unsigned long))
goto out;
ret = -ENODEV;
nvram_addr = buffer[0];
mmio_nvram_len = buffer[1];
if ( (!mmio_nvram_len) || (!nvram_addr) )
goto out;
mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len);
if (!mmio_nvram_start)
goto out;
printk(KERN_INFO "mmio NVRAM, %luk mapped to %p\n",
mmio_nvram_len >> 10, mmio_nvram_start);
ppc_md.nvram_read = mmio_nvram_read;
ppc_md.nvram_write = mmio_nvram_write;
ppc_md.nvram_size = mmio_nvram_get_size;
out:
of_node_put(nvram_node);
return ret;
}
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