1/* 2 * Generic /dev/nvram driver for architectures providing some 3 * "generic" hooks, that is : 4 * 5 * nvram_read_byte, nvram_write_byte, nvram_sync, nvram_get_size 6 * 7 * Note that an additional hook is supported for PowerMac only 8 * for getting the nvram "partition" informations 9 * 10 */ 11 12#define NVRAM_VERSION "1.1" 13 14#include <linux/module.h> 15 16#include <linux/types.h> 17#include <linux/errno.h> 18#include <linux/fs.h> 19#include <linux/miscdevice.h> 20#include <linux/fcntl.h> 21#include <linux/init.h> 22#include <linux/smp_lock.h> 23#include <asm/uaccess.h> 24#include <asm/nvram.h> 25#ifdef CONFIG_PPC_PMAC 26#include <asm/machdep.h> 27#endif 28 29#define NVRAM_SIZE 8192 30 31static ssize_t nvram_len; 32 33static loff_t nvram_llseek(struct file *file, loff_t offset, int origin) 34{ 35 switch (origin) { 36 case 1: 37 offset += file->f_pos; 38 break; 39 case 2: 40 offset += nvram_len; 41 break; 42 } 43 if (offset < 0) 44 return -EINVAL; 45 46 file->f_pos = offset; 47 48 return file->f_pos; 49} 50 51static ssize_t read_nvram(struct file *file, char __user *buf, 52 size_t count, loff_t *ppos) 53{ 54 unsigned int i; 55 char __user *p = buf; 56 57 if (!access_ok(VERIFY_WRITE, buf, count)) 58 return -EFAULT; 59 if (*ppos >= nvram_len) 60 return 0; 61 for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) 62 if (__put_user(nvram_read_byte(i), p)) 63 return -EFAULT; 64 *ppos = i; 65 return p - buf; 66} 67 68static ssize_t write_nvram(struct file *file, const char __user *buf, 69 size_t count, loff_t *ppos) 70{ 71 unsigned int i; 72 const char __user *p = buf; 73 char c; 74 75 if (!access_ok(VERIFY_READ, buf, count)) 76 return -EFAULT; 77 if (*ppos >= nvram_len) 78 return 0; 79 for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) { 80 if (__get_user(c, p)) 81 return -EFAULT; 82 nvram_write_byte(c, i); 83 } 84 *ppos = i; 85 return p - buf; 86} 87 88static int nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 89{ 90 switch(cmd) { 91#ifdef CONFIG_PPC_PMAC 92 case OBSOLETE_PMAC_NVRAM_GET_OFFSET: 93 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n"); 94 case IOC_NVRAM_GET_OFFSET: { 95 int part, offset; 96 97 if (!machine_is(powermac)) 98 return -EINVAL; 99 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0) 100 return -EFAULT; 101 if (part < pmac_nvram_OF || part > pmac_nvram_NR) 102 return -EINVAL; 103 offset = pmac_get_partition(part); 104 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0) 105 return -EFAULT; 106 break; 107 } 108#endif /* CONFIG_PPC_PMAC */ 109 case IOC_NVRAM_SYNC: 110 nvram_sync(); 111 break; 112 default: 113 return -EINVAL; 114 } 115 116 return 0; 117} 118 119static long nvram_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 120{ 121 int ret; 122 123 lock_kernel(); 124 ret = nvram_ioctl(file, cmd, arg); 125 unlock_kernel(); 126 127 return ret; 128} 129 130const struct file_operations nvram_fops = { 131 .owner = THIS_MODULE, 132 .llseek = nvram_llseek, 133 .read = read_nvram, 134 .write = write_nvram, 135 .unlocked_ioctl = nvram_unlocked_ioctl, 136}; 137 138static struct miscdevice nvram_dev = { 139 NVRAM_MINOR, 140 "nvram", 141 &nvram_fops 142}; 143 144int __init nvram_init(void) 145{ 146 int ret = 0; 147 148 printk(KERN_INFO "Generic non-volatile memory driver v%s\n", 149 NVRAM_VERSION); 150 ret = misc_register(&nvram_dev); 151 if (ret != 0) 152 goto out; 153 154 nvram_len = nvram_get_size(); 155 if (nvram_len < 0) 156 nvram_len = NVRAM_SIZE; 157 158out: 159 return ret; 160} 161 162void __exit nvram_cleanup(void) 163{ 164 misc_deregister( &nvram_dev ); 165} 166 167module_init(nvram_init); 168module_exit(nvram_cleanup); 169MODULE_LICENSE("GPL"); 170