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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* memory mapped NVRAM
*
* (C) Copyright IBM Corp. 2005
*
* Authors : Utz Bacher <utz.bacher@de.ibm.com>
*/
#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 unsigned char mmio_nvram_read_val(int addr)
{
unsigned long flags;
unsigned char val;
if (addr >= mmio_nvram_len)
return 0xff;
spin_lock_irqsave(&mmio_nvram_lock, flags);
val = ioread8(mmio_nvram_start + addr);
spin_unlock_irqrestore(&mmio_nvram_lock, flags);
return val;
}
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 void mmio_nvram_write_val(int addr, unsigned char val)
{
unsigned long flags;
if (addr < mmio_nvram_len) {
spin_lock_irqsave(&mmio_nvram_lock, flags);
iowrite8(val, mmio_nvram_start + addr);
spin_unlock_irqrestore(&mmio_nvram_lock, flags);
}
}
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)
nvram_node = of_find_compatible_node(NULL, 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 = resource_size(&r);
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_val = mmio_nvram_read_val;
ppc_md.nvram_write_val = mmio_nvram_write_val;
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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