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 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 loff_t nvram_llseek(struct file *file, loff_t offset, int origin) 32{ 33 lock_kernel(); 34 switch (origin) { 35 case 1: 36 offset += file->f_pos; 37 break; 38 case 2: 39 offset += NVRAM_SIZE; 40 break; 41 } 42 if (offset < 0) { 43 unlock_kernel(); 44 return -EINVAL; 45 } 46 file->f_pos = offset; 47 unlock_kernel(); 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_SIZE) 60 return 0; 61 for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++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_SIZE) 78 return 0; 79 for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++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 inode *inode, struct file *file, 89 unsigned int cmd, unsigned long arg) 90{ 91 switch(cmd) { 92#ifdef CONFIG_PPC_PMAC 93 case OBSOLETE_PMAC_NVRAM_GET_OFFSET: 94 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n"); 95 case IOC_NVRAM_GET_OFFSET: { 96 int part, offset; 97 98 if (!machine_is(powermac)) 99 return -EINVAL; 100 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0) 101 return -EFAULT; 102 if (part < pmac_nvram_OF || part > pmac_nvram_NR) 103 return -EINVAL; 104 offset = pmac_get_partition(part); 105 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0) 106 return -EFAULT; 107 break; 108 } 109#endif /* CONFIG_PPC_PMAC */ 110 case IOC_NVRAM_SYNC: 111 nvram_sync(); 112 break; 113 default: 114 return -EINVAL; 115 } 116 117 return 0; 118} 119 120const struct file_operations nvram_fops = { 121 .owner = THIS_MODULE, 122 .llseek = nvram_llseek, 123 .read = read_nvram, 124 .write = write_nvram, 125 .ioctl = nvram_ioctl, 126}; 127 128static struct miscdevice nvram_dev = { 129 NVRAM_MINOR, 130 "nvram", 131 &nvram_fops 132}; 133 134int __init nvram_init(void) 135{ 136 printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n", 137 NVRAM_VERSION); 138 return misc_register(&nvram_dev); 139} 140 141void __exit nvram_cleanup(void) 142{ 143 misc_deregister( &nvram_dev ); 144} 145 146module_init(nvram_init); 147module_exit(nvram_cleanup); 148MODULE_LICENSE("GPL"); 149