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 33 static void __iomem *mmio_nvram_start; 34 static long mmio_nvram_len; 35 static DEFINE_SPINLOCK(mmio_nvram_lock); 36 37 static 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 56 static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index) 57 { 58 unsigned long flags; 59 60 if (*index >= mmio_nvram_len) 61 return 0; 62 if (*index + count > mmio_nvram_len) 63 count = mmio_nvram_len - *index; 64 65 spin_lock_irqsave(&mmio_nvram_lock, flags); 66 67 memcpy_toio(mmio_nvram_start + *index, buf, count); 68 69 spin_unlock_irqrestore(&mmio_nvram_lock, flags); 70 71 *index += count; 72 return count; 73 } 74 75 static ssize_t mmio_nvram_get_size(void) 76 { 77 return mmio_nvram_len; 78 } 79 80 int __init mmio_nvram_init(void) 81 { 82 struct device_node *nvram_node; 83 unsigned long nvram_addr; 84 struct resource r; 85 int ret; 86 87 nvram_node = of_find_node_by_type(NULL, "nvram"); 88 if (!nvram_node) { 89 printk(KERN_WARNING "nvram: no node found in device-tree\n"); 90 return -ENODEV; 91 } 92 93 ret = of_address_to_resource(nvram_node, 0, &r); 94 if (ret) { 95 printk(KERN_WARNING "nvram: failed to get address (err %d)\n", 96 ret); 97 goto out; 98 } 99 nvram_addr = r.start; 100 mmio_nvram_len = r.end - r.start + 1; 101 if ( (!mmio_nvram_len) || (!nvram_addr) ) { 102 printk(KERN_WARNING "nvram: address or length is 0\n"); 103 ret = -EIO; 104 goto out; 105 } 106 107 mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len); 108 if (!mmio_nvram_start) { 109 printk(KERN_WARNING "nvram: failed to ioremap\n"); 110 ret = -ENOMEM; 111 goto out; 112 } 113 114 printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n", 115 mmio_nvram_len >> 10, nvram_addr, mmio_nvram_start); 116 117 ppc_md.nvram_read = mmio_nvram_read; 118 ppc_md.nvram_write = mmio_nvram_write; 119 ppc_md.nvram_size = mmio_nvram_get_size; 120 121 out: 122 of_node_put(nvram_node); 123 return ret; 124 } 125