Logo Search packages:      
Sourcecode: linux version File versions  Download package

mmio_nvram.c

/*
 * 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;
      unsigned long nvram_addr;
      struct resource r;
      int ret;

      nvram_node = of_find_node_by_type(NULL, "nvram");
      if (!nvram_node) {
            printk(KERN_WARNING "nvram: no node found in device-tree\n");
            return -ENODEV;
      }

      ret = of_address_to_resource(nvram_node, 0, &r);
      if (ret) {
            printk(KERN_WARNING "nvram: failed to get address (err %d)\n",
                   ret);
            goto out;
      }
      nvram_addr = r.start;
      mmio_nvram_len = r.end - r.start + 1;
      if ( (!mmio_nvram_len) || (!nvram_addr) ) {
            printk(KERN_WARNING "nvram: address or length is 0\n");
            ret = -EIO;
            goto out;
      }

      mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len);
      if (!mmio_nvram_start) {
            printk(KERN_WARNING "nvram: failed to ioremap\n");
            ret = -ENOMEM;
            goto out;
      }

      printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n",
             mmio_nvram_len >> 10, nvram_addr, 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;
}

Generated by  Doxygen 1.6.0   Back to index