96 lines
2.2 KiB
C
96 lines
2.2 KiB
C
|
// SPDX-License-Identifier: GPL-2.0-or-later
|
||
|
|
/*
|
||
|
|
* c 2001 PPC 64 Team, IBM Corp
|
||
|
|
*
|
||
|
|
* /dev/nvram driver for PPC
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/module.h>
|
||
|
|
#include <linux/init.h>
|
||
|
|
#include <linux/spinlock.h>
|
||
|
|
#include <linux/uaccess.h>
|
||
|
|
#include <asm/prom.h>
|
||
|
|
#include <asm/machdep.h>
|
||
|
|
#include <asm/rtas.h>
|
||
|
|
#include "chrp.h"
|
||
|
|
|
||
|
|
static unsigned int nvram_size;
|
||
|
|
static unsigned char nvram_buf[4];
|
||
|
|
static DEFINE_SPINLOCK(nvram_lock);
|
||
|
|
|
||
|
|
static unsigned char chrp_nvram_read_val(int addr)
|
||
|
|
{
|
||
|
|
unsigned int done;
|
||
|
|
unsigned long flags;
|
||
|
|
unsigned char ret;
|
||
|
|
|
||
|
|
if (addr >= nvram_size) {
|
||
|
|
printk(KERN_DEBUG "%s: read addr %d > nvram_size %u\n",
|
||
|
|
current->comm, addr, nvram_size);
|
||
|
|
return 0xff;
|
||
|
|
}
|
||
|
|
spin_lock_irqsave(&nvram_lock, flags);
|
||
|
|
if ((rtas_call(rtas_token("nvram-fetch"), 3, 2, &done, addr,
|
||
|
|
__pa(nvram_buf), 1) != 0) || 1 != done)
|
||
|
|
ret = 0xff;
|
||
|
|
else
|
||
|
|
ret = nvram_buf[0];
|
||
|
|
spin_unlock_irqrestore(&nvram_lock, flags);
|
||
|
|
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void chrp_nvram_write_val(int addr, unsigned char val)
|
||
|
|
{
|
||
|
|
unsigned int done;
|
||
|
|
unsigned long flags;
|
||
|
|
|
||
|
|
if (addr >= nvram_size) {
|
||
|
|
printk(KERN_DEBUG "%s: write addr %d > nvram_size %u\n",
|
||
|
|
current->comm, addr, nvram_size);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
spin_lock_irqsave(&nvram_lock, flags);
|
||
|
|
nvram_buf[0] = val;
|
||
|
|
if ((rtas_call(rtas_token("nvram-store"), 3, 2, &done, addr,
|
||
|
|
__pa(nvram_buf), 1) != 0) || 1 != done)
|
||
|
|
printk(KERN_DEBUG "rtas IO error storing 0x%02x at %d", val, addr);
|
||
|
|
spin_unlock_irqrestore(&nvram_lock, flags);
|
||
|
|
}
|
||
|
|
|
||
|
|
static ssize_t chrp_nvram_size(void)
|
||
|
|
{
|
||
|
|
return nvram_size;
|
||
|
|
}
|
||
|
|
|
||
|
|
void __init chrp_nvram_init(void)
|
||
|
|
{
|
||
|
|
struct device_node *nvram;
|
||
|
|
const __be32 *nbytes_p;
|
||
|
|
unsigned int proplen;
|
||
|
|
|
||
|
|
nvram = of_find_node_by_type(NULL, "nvram");
|
||
|
|
if (nvram == NULL)
|
||
|
|
return;
|
||
|
|
|
||
|
|
nbytes_p = of_get_property(nvram, "#bytes", &proplen);
|
||
|
|
if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
|
||
|
|
of_node_put(nvram);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
nvram_size = be32_to_cpup(nbytes_p);
|
||
|
|
|
||
|
|
printk(KERN_INFO "CHRP nvram contains %u bytes\n", nvram_size);
|
||
|
|
of_node_put(nvram);
|
||
|
|
|
||
|
|
ppc_md.nvram_read_val = chrp_nvram_read_val;
|
||
|
|
ppc_md.nvram_write_val = chrp_nvram_write_val;
|
||
|
|
ppc_md.nvram_size = chrp_nvram_size;
|
||
|
|
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
MODULE_LICENSE("GPL v2");
|