125 lines
3.0 KiB
C
125 lines
3.0 KiB
C
/*
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* memory mapped NVRAM
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*
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* (C) Copyright IBM Corp. 2005
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*
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* Authors : Utz Bacher <utz.bacher@de.ibm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <asm/machdep.h>
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#include <asm/nvram.h>
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#include <asm/prom.h>
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static void __iomem *mmio_nvram_start;
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static long mmio_nvram_len;
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static DEFINE_SPINLOCK(mmio_nvram_lock);
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static ssize_t mmio_nvram_read(char *buf, size_t count, loff_t *index)
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{
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unsigned long flags;
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if (*index >= mmio_nvram_len)
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return 0;
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if (*index + count > mmio_nvram_len)
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count = mmio_nvram_len - *index;
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spin_lock_irqsave(&mmio_nvram_lock, flags);
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memcpy_fromio(buf, mmio_nvram_start + *index, count);
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spin_unlock_irqrestore(&mmio_nvram_lock, flags);
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*index += count;
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return count;
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}
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static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index)
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{
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unsigned long flags;
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if (*index >= mmio_nvram_len)
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return 0;
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if (*index + count > mmio_nvram_len)
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count = mmio_nvram_len - *index;
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spin_lock_irqsave(&mmio_nvram_lock, flags);
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memcpy_toio(mmio_nvram_start + *index, buf, count);
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spin_unlock_irqrestore(&mmio_nvram_lock, flags);
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*index += count;
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return count;
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}
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static ssize_t mmio_nvram_get_size(void)
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{
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return mmio_nvram_len;
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}
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int __init mmio_nvram_init(void)
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{
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struct device_node *nvram_node;
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unsigned long nvram_addr;
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struct resource r;
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int ret;
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nvram_node = of_find_node_by_type(NULL, "nvram");
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if (!nvram_node) {
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printk(KERN_WARNING "nvram: no node found in device-tree\n");
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return -ENODEV;
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}
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ret = of_address_to_resource(nvram_node, 0, &r);
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if (ret) {
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printk(KERN_WARNING "nvram: failed to get address (err %d)\n",
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ret);
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goto out;
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}
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nvram_addr = r.start;
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mmio_nvram_len = r.end - r.start + 1;
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if ( (!mmio_nvram_len) || (!nvram_addr) ) {
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printk(KERN_WARNING "nvram: address or length is 0\n");
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ret = -EIO;
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goto out;
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}
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mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len);
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if (!mmio_nvram_start) {
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printk(KERN_WARNING "nvram: failed to ioremap\n");
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ret = -ENOMEM;
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goto out;
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}
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printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n",
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mmio_nvram_len >> 10, nvram_addr, mmio_nvram_start);
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ppc_md.nvram_read = mmio_nvram_read;
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ppc_md.nvram_write = mmio_nvram_write;
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ppc_md.nvram_size = mmio_nvram_get_size;
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out:
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of_node_put(nvram_node);
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return ret;
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}
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