146 lines
3.1 KiB
C
146 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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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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#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 unsigned char mmio_nvram_read_val(int addr)
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{
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unsigned long flags;
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unsigned char val;
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if (addr >= mmio_nvram_len)
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return 0xff;
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spin_lock_irqsave(&mmio_nvram_lock, flags);
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val = ioread8(mmio_nvram_start + addr);
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spin_unlock_irqrestore(&mmio_nvram_lock, flags);
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return val;
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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 void mmio_nvram_write_val(int addr, unsigned char val)
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{
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unsigned long flags;
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if (addr < mmio_nvram_len) {
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spin_lock_irqsave(&mmio_nvram_lock, flags);
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iowrite8(val, mmio_nvram_start + addr);
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spin_unlock_irqrestore(&mmio_nvram_lock, flags);
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}
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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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nvram_node = of_find_compatible_node(NULL, 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 = resource_size(&r);
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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_val = mmio_nvram_read_val;
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ppc_md.nvram_write_val = mmio_nvram_write_val;
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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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