/*
* c 2001 PPC 64 Team, IBM Corp
*
* 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 of the License, or (at your option) any later version.
*
* /dev/nvram driver for PPC64
*
* This perhaps should live in drivers/char
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
#include <asm/nvram.h>
#include <asm/rtas.h>
#include <asm/prom.h>
#include <asm/machdep.h>
static unsigned int nvram_size;
static int nvram_fetch, nvram_store;
static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */
static DEFINE_SPINLOCK(nvram_lock);
static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
{
unsigned int i;
unsigned long len;
int done;
unsigned long flags;
char *p = buf;
if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
return -ENODEV;
if (*index >= nvram_size)
return 0;
i = *index;
if (i + count > nvram_size)
count = nvram_size - i;
spin_lock_irqsave(&nvram_lock, flags);
for (; count != 0; count -= len) {
len = count;
if (len > NVRW_CNT)
len = NVRW_CNT;
if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf),
len) != 0) || len != done) {
spin_unlock_irqrestore(&nvram_lock, flags);
return -EIO;
}
memcpy(p, nvram_buf, len);
p += len;
i += len;
}
spin_unlock_irqrestore(&nvram_lock, flags);
*index = i;
return p - buf;
}
static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
{
unsigned int i;
unsigned long len;
int done;
unsigned long flags;
const char *p = buf;
if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
return -ENODEV;
if (*index >= nvram_size)
return 0;
i = *index;
if (i + count > nvram_size)
count = nvram_size - i;
spin_lock_irqsave(&nvram_lock, flags);
for (; count != 0; count -= len) {
len = count;
if (len > NVRW_CNT)
len = NVRW_CNT;
memcpy(nvram_buf, p, len);
if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf),
len) != 0) || len != done) {
spin_unlock_irqrestore(&nvram_lock, flags);
return -EIO;
}
p += len;
i += len;
}
spin_unlock_irqrestore(&nvram_lock, flags);
*index = i;
return p - buf;
}
static ssize_t pSeries_nvram_get_size(void)
{
return nvram_size ? nvram_size : -ENODEV;
}
int __init pSeries_nvram_init(void)
{
struct device_node *nvram;
unsigned int *nbytes_p, proplen;
nvram = of_find_node_by_type(NULL, "nvram");
if (nvram == NULL)
return -ENODEV;
nbytes_p = (unsigned int *)get_property(nvram, "#bytes", &proplen);
if (nbytes_p == NULL || proplen != sizeof(unsigned int))
return -EIO;
nvram_size = *nbytes_p;
nvram_fetch = rtas_token("nvram-fetch");
nvram_store = rtas_token("nvram-store");
printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
of_node_put(nvram);
ppc_md.nvram_read = pSeries_nvram_read;
ppc_md.nvram_write = pSeries_nvram_write;
ppc_md.nvram_size = pSeries_nvram_get_size;
return 0;
}
