patch-pre2.0.8 linux/arch/ppc/kernel/ramdisk_drvr.c

• Lines: 85
• Date: Mon May 27 12:00:58 1996
• Orig file: pre2.0.7/linux/arch/ppc/kernel/ramdisk_drvr.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file pre2.0.7/linux/arch/ppc/kernel/ramdisk_drvr.c linux/arch/ppc/kernel/ramdisk_drvr.c
@@ -0,0 +1,84 @@
+/*
+ *  linux/kernel/blk_drv/ramdisk.c
+ *
+ *  Written by Theodore Ts'o, 12/2/91
+ *
+ * Modifications by Fred N. van Kempen to allow for bootable root
+ * disks (which are used in LINUX/Pro).  Also some cleanups.  03/03/93
+ */
+
+
+#include <linux/sched.h>
+#include <linux/minix_fs.h>
+#include <linux/ext2_fs.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+
+#include <asm/system.h>
+#include <asm/segment.h>
+
+#define MAJOR_NR  MEM_MAJOR
+#include <linux/blk.h>
+
+#define RAMDISK_MINOR	1
+
+char	*rd_start;
+int	rd_length = 0;
+static int rd_blocksizes[2] = {0, 0};
+
+static void rd_request(void)
+{
+	int	len;
+	char	*addr;
+
+repeat:
+	INIT_REQUEST;
+	addr = rd_start + (CURRENT->sector << 9);
+	len = CURRENT->current_nr_sectors << 9;
+
+	if (CURRENT-> cmd == WRITE) {
+		(void ) memcpy(addr,
+			      CURRENT->buffer,
+			      len);
+	} else if (CURRENT->cmd == READ) {
+		(void) memcpy(CURRENT->buffer, 
+			      addr,
+			      len);
+	} else
+		panic("RAMDISK: unknown RAM disk command !\n");
+	end_request(1);
+	goto repeat;
+}
+
+static struct file_operations rd_fops = {
+	NULL,			/* lseek - default */
+	block_read,		/* read - general block-dev read */
+	block_write,		/* write - general block-dev write */
+	NULL,			/* readdir - bad */
+	NULL,			/* select */
+	NULL,			/* ioctl */
+	NULL,			/* mmap */
+	NULL,			/* no special open code */
+	NULL,			/* no special release code */
+	block_fsync		/* fsync */
+};
+
+void
+rd_preloaded_init(char *start, int length)
+{
+	int	i;
+
+	if (register_blkdev(MEM_MAJOR,"rd",&rd_fops)) {
+		printk("RAMDISK: Unable to get major %d.\n", MEM_MAJOR);
+		return 0;
+	}
+	blk_dev[MEM_MAJOR].request_fn = DEVICE_REQUEST;
+	rd_start = start;
+	rd_length = length;
+	for(i=0;i<2;i++) rd_blocksizes[i] = 1024;
+	blksize_size[MAJOR_NR] = rd_blocksizes;
+	/* We loaded the file system image.  Prepare for mounting it. */
+	ROOT_DEV = to_kdev_t((MEM_MAJOR << 8) | RAMDISK_MINOR);
+}