1/* 2 * memory mapped NVRAM 3 * 4 * (C) Copyright IBM Corp. 2005 5 * 6 * Authors : Utz Bacher <utz.bacher@de.ibm.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2, or (at your option) 11 * any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 21 */ 22 23#include <linux/fs.h> 24#include <linux/init.h> 25#include <linux/kernel.h> 26#include <linux/spinlock.h> 27#include <linux/types.h> 28 29#include <asm/machdep.h> 30#include <asm/nvram.h> 31#include <asm/prom.h> 32 33static void __iomem *mmio_nvram_start; 34static long mmio_nvram_len; 35static DEFINE_SPINLOCK(mmio_nvram_lock); 36 37static ssize_t mmio_nvram_read(char *buf, size_t count, loff_t *index) 38{ 39 unsigned long flags; 40 41 if (*index >= mmio_nvram_len) 42 return 0; 43 if (*index + count > mmio_nvram_len) 44 count = mmio_nvram_len - *index; 45 46 spin_lock_irqsave(&mmio_nvram_lock, flags); 47 48 memcpy_fromio(buf, mmio_nvram_start + *index, count); 49 50 spin_unlock_irqrestore(&mmio_nvram_lock, flags); 51 52 *index += count; 53 return count; 54} 55 56static unsigned char mmio_nvram_read_val(int addr) 57{ 58 unsigned long flags; 59 unsigned char val; 60 61 if (addr >= mmio_nvram_len) 62 return 0xff; 63 64 spin_lock_irqsave(&mmio_nvram_lock, flags); 65 66 val = ioread8(mmio_nvram_start + addr); 67 68 spin_unlock_irqrestore(&mmio_nvram_lock, flags); 69 70 return val; 71} 72 73static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index) 74{ 75 unsigned long flags; 76 77 if (*index >= mmio_nvram_len) 78 return 0; 79 if (*index + count > mmio_nvram_len) 80 count = mmio_nvram_len - *index; 81 82 spin_lock_irqsave(&mmio_nvram_lock, flags); 83 84 memcpy_toio(mmio_nvram_start + *index, buf, count); 85 86 spin_unlock_irqrestore(&mmio_nvram_lock, flags); 87 88 *index += count; 89 return count; 90} 91 92void mmio_nvram_write_val(int addr, unsigned char val) 93{ 94 unsigned long flags; 95 96 if (addr < mmio_nvram_len) { 97 spin_lock_irqsave(&mmio_nvram_lock, flags); 98 99 iowrite8(val, mmio_nvram_start + addr); 100 101 spin_unlock_irqrestore(&mmio_nvram_lock, flags); 102 } 103} 104 105static ssize_t mmio_nvram_get_size(void) 106{ 107 return mmio_nvram_len; 108} 109 110int __init mmio_nvram_init(void) 111{ 112 struct device_node *nvram_node; 113 unsigned long nvram_addr; 114 struct resource r; 115 int ret; 116 117 nvram_node = of_find_node_by_type(NULL, "nvram"); 118 if (!nvram_node) { 119 printk(KERN_WARNING "nvram: no node found in device-tree\n"); 120 return -ENODEV; 121 } 122 123 ret = of_address_to_resource(nvram_node, 0, &r); 124 if (ret) { 125 printk(KERN_WARNING "nvram: failed to get address (err %d)\n", 126 ret); 127 goto out; 128 } 129 nvram_addr = r.start; 130 mmio_nvram_len = r.end - r.start + 1; 131 if ( (!mmio_nvram_len) || (!nvram_addr) ) { 132 printk(KERN_WARNING "nvram: address or length is 0\n"); 133 ret = -EIO; 134 goto out; 135 } 136 137 mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len); 138 if (!mmio_nvram_start) { 139 printk(KERN_WARNING "nvram: failed to ioremap\n"); 140 ret = -ENOMEM; 141 goto out; 142 } 143 144 printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n", 145 mmio_nvram_len >> 10, nvram_addr, mmio_nvram_start); 146 147 ppc_md.nvram_read_val = mmio_nvram_read_val; 148 ppc_md.nvram_write_val = mmio_nvram_write_val; 149 ppc_md.nvram_read = mmio_nvram_read; 150 ppc_md.nvram_write = mmio_nvram_write; 151 ppc_md.nvram_size = mmio_nvram_get_size; 152 153out: 154 of_node_put(nvram_node); 155 return ret; 156} 157