v4.19.13 snapshot.
diff --git a/drivers/char/generic_nvram.c b/drivers/char/generic_nvram.c
new file mode 100644
index 0000000..14e728f
--- /dev/null
+++ b/drivers/char/generic_nvram.c
@@ -0,0 +1,159 @@
+/*
+ * Generic /dev/nvram driver for architectures providing some
+ * "generic" hooks, that is :
+ *
+ * nvram_read_byte, nvram_write_byte, nvram_sync, nvram_get_size
+ *
+ * Note that an additional hook is supported for PowerMac only
+ * for getting the nvram "partition" informations
+ *
+ */
+
+#define NVRAM_VERSION "1.1"
+
+#include <linux/module.h>
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/fcntl.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/pagemap.h>
+#include <linux/uaccess.h>
+#include <asm/nvram.h>
+#ifdef CONFIG_PPC_PMAC
+#include <asm/machdep.h>
+#endif
+
+#define NVRAM_SIZE 8192
+
+static DEFINE_MUTEX(nvram_mutex);
+static ssize_t nvram_len;
+
+static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
+{
+ return generic_file_llseek_size(file, offset, origin,
+ MAX_LFS_FILESIZE, nvram_len);
+}
+
+static ssize_t read_nvram(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned int i;
+ char __user *p = buf;
+
+ if (!access_ok(VERIFY_WRITE, buf, count))
+ return -EFAULT;
+ if (*ppos >= nvram_len)
+ return 0;
+ for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count)
+ if (__put_user(nvram_read_byte(i), p))
+ return -EFAULT;
+ *ppos = i;
+ return p - buf;
+}
+
+static ssize_t write_nvram(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned int i;
+ const char __user *p = buf;
+ char c;
+
+ if (!access_ok(VERIFY_READ, buf, count))
+ return -EFAULT;
+ if (*ppos >= nvram_len)
+ return 0;
+ for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) {
+ if (__get_user(c, p))
+ return -EFAULT;
+ nvram_write_byte(c, i);
+ }
+ *ppos = i;
+ return p - buf;
+}
+
+static int nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ switch(cmd) {
+#ifdef CONFIG_PPC_PMAC
+ case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
+ printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
+ case IOC_NVRAM_GET_OFFSET: {
+ int part, offset;
+
+ if (!machine_is(powermac))
+ return -EINVAL;
+ if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
+ return -EFAULT;
+ if (part < pmac_nvram_OF || part > pmac_nvram_NR)
+ return -EINVAL;
+ offset = pmac_get_partition(part);
+ if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
+ return -EFAULT;
+ break;
+ }
+#endif /* CONFIG_PPC_PMAC */
+ case IOC_NVRAM_SYNC:
+ nvram_sync();
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static long nvram_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ int ret;
+
+ mutex_lock(&nvram_mutex);
+ ret = nvram_ioctl(file, cmd, arg);
+ mutex_unlock(&nvram_mutex);
+
+ return ret;
+}
+
+const struct file_operations nvram_fops = {
+ .owner = THIS_MODULE,
+ .llseek = nvram_llseek,
+ .read = read_nvram,
+ .write = write_nvram,
+ .unlocked_ioctl = nvram_unlocked_ioctl,
+};
+
+static struct miscdevice nvram_dev = {
+ NVRAM_MINOR,
+ "nvram",
+ &nvram_fops
+};
+
+int __init nvram_init(void)
+{
+ int ret = 0;
+
+ printk(KERN_INFO "Generic non-volatile memory driver v%s\n",
+ NVRAM_VERSION);
+ ret = misc_register(&nvram_dev);
+ if (ret != 0)
+ goto out;
+
+ nvram_len = nvram_get_size();
+ if (nvram_len < 0)
+ nvram_len = NVRAM_SIZE;
+
+out:
+ return ret;
+}
+
+void __exit nvram_cleanup(void)
+{
+ misc_deregister( &nvram_dev );
+}
+
+module_init(nvram_init);
+module_exit(nvram_cleanup);
+MODULE_LICENSE("GPL");