mirror of
https://github.com/torvalds/linux.git
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160 lines
3.3 KiB
C
160 lines
3.3 KiB
C
/*
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* Generic /dev/nvram driver for architectures providing some
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* "generic" hooks, that is :
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*
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* nvram_read_byte, nvram_write_byte, nvram_sync, nvram_get_size
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*
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* Note that an additional hook is supported for PowerMac only
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* for getting the nvram "partition" informations
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*
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*/
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#define NVRAM_VERSION "1.1"
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#include <linux/fcntl.h>
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#include <linux/init.h>
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#include <linux/mutex.h>
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#include <linux/pagemap.h>
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#include <asm/uaccess.h>
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#include <asm/nvram.h>
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#ifdef CONFIG_PPC_PMAC
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#include <asm/machdep.h>
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#endif
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#define NVRAM_SIZE 8192
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static DEFINE_MUTEX(nvram_mutex);
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static ssize_t nvram_len;
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static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
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{
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return generic_file_llseek_size(file, offset, origin,
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MAX_LFS_FILESIZE, nvram_len);
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}
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static ssize_t read_nvram(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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unsigned int i;
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char __user *p = buf;
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if (!access_ok(VERIFY_WRITE, buf, count))
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return -EFAULT;
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if (*ppos >= nvram_len)
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return 0;
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for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count)
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if (__put_user(nvram_read_byte(i), p))
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return -EFAULT;
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*ppos = i;
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return p - buf;
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}
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static ssize_t write_nvram(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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unsigned int i;
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const char __user *p = buf;
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char c;
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if (!access_ok(VERIFY_READ, buf, count))
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return -EFAULT;
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if (*ppos >= nvram_len)
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return 0;
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for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) {
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if (__get_user(c, p))
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return -EFAULT;
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nvram_write_byte(c, i);
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}
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*ppos = i;
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return p - buf;
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}
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static int nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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switch(cmd) {
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#ifdef CONFIG_PPC_PMAC
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case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
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printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
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case IOC_NVRAM_GET_OFFSET: {
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int part, offset;
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if (!machine_is(powermac))
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return -EINVAL;
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if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
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return -EFAULT;
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if (part < pmac_nvram_OF || part > pmac_nvram_NR)
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return -EINVAL;
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offset = pmac_get_partition(part);
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if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
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return -EFAULT;
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break;
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}
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#endif /* CONFIG_PPC_PMAC */
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case IOC_NVRAM_SYNC:
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nvram_sync();
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static long nvram_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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int ret;
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mutex_lock(&nvram_mutex);
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ret = nvram_ioctl(file, cmd, arg);
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mutex_unlock(&nvram_mutex);
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return ret;
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}
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const struct file_operations nvram_fops = {
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.owner = THIS_MODULE,
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.llseek = nvram_llseek,
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.read = read_nvram,
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.write = write_nvram,
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.unlocked_ioctl = nvram_unlocked_ioctl,
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};
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static struct miscdevice nvram_dev = {
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NVRAM_MINOR,
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"nvram",
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&nvram_fops
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};
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int __init nvram_init(void)
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{
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int ret = 0;
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printk(KERN_INFO "Generic non-volatile memory driver v%s\n",
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NVRAM_VERSION);
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ret = misc_register(&nvram_dev);
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if (ret != 0)
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goto out;
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nvram_len = nvram_get_size();
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if (nvram_len < 0)
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nvram_len = NVRAM_SIZE;
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out:
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return ret;
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}
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void __exit nvram_cleanup(void)
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{
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misc_deregister( &nvram_dev );
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}
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module_init(nvram_init);
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module_exit(nvram_cleanup);
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MODULE_LICENSE("GPL");
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