The block device driver for systemsim is currently
required for running on the Cell systemsim port, which
does not simulate any other block devices.

From: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>

Index: linux-2.6.16-rc/drivers/block/Makefile
===================================================================
--- linux-2.6.16-rc.orig/drivers/block/Makefile
+++ linux-2.6.16-rc/drivers/block/Makefile
@@ -28,6 +28,6 @@ obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o
 obj-$(CONFIG_BLK_DEV_CRYPTOLOOP) += cryptoloop.o
 
 obj-$(CONFIG_VIODASD)		+= viodasd.o
+obj-$(CONFIG_BLK_DEV_SYSTEMSIM)	+= systemsim_bd.o
 obj-$(CONFIG_BLK_DEV_SX8)	+= sx8.o
 obj-$(CONFIG_BLK_DEV_UB)	+= ub.o
-
Index: linux-2.6.16-rc/drivers/block/Kconfig
===================================================================
--- linux-2.6.16-rc.orig/drivers/block/Kconfig
+++ linux-2.6.16-rc/drivers/block/Kconfig
@@ -409,6 +409,13 @@ config BLK_DEV_INITRD
 	  "real" root file system, etc. See <file:Documentation/initrd.txt>
 	  for details.
 
+config BLK_DEV_SYSTEMSIM
+	depends on PPC_SYSTEMSIM
+	tristate "IBM Full System Simulator Bogus Disk Support"
+	default y
+	help
+	  Provides quick access to disk images in the simulator without
+	  simulating a full IDE or SCSI device.
 
 config CDROM_PKTCDVD
 	tristate "Packet writing on CD/DVD media"
Index: linux-2.6.16-rc/drivers/block/systemsim_bd.c
===================================================================
--- /dev/null
+++ linux-2.6.16-rc/drivers/block/systemsim_bd.c
@@ -0,0 +1,285 @@
+/*
+ *  Bogus Block Driver for PowerPC Full System Simulator
+ *
+ *  (C) Copyright IBM Corporation 2003-2005
+ *
+ *  Bogus Disk Driver
+ *
+ *  Author: Eric Van Hensbegren <ericvh@gmail.com>
+ *
+ *    inspired by drivers/block/nbd.c
+ *    written by Pavel Machek and Steven Whitehouse
+ *
+ *  Some code is from the IBM Full System Simulator Group in ARL
+ *  Author: PAtrick Bohrer <IBM Austin Research Lab>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to:
+ * Free Software Foundation
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/major.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/ioctl.h>
+#include <linux/blkdev.h>
+#include <net/sock.h>
+
+#include <asm/systemsim.h>
+
+#include <linux/devfs_fs_kernel.h>
+
+#include <asm/uaccess.h>
+#include <asm/types.h>
+
+#define MAJOR_NR 42
+#define MAX_MBD 128
+
+#define MBD_SET_BLKSIZE _IO( 0xab, 1 )
+#define MBD_SET_SIZE    _IO( 0xab, 2 )
+#define MBD_SET_SIZE_BLOCKS     _IO( 0xab, 7 )
+#define MBD_DISCONNECT  _IO( 0xab, 8 )
+
+struct mbd_device {
+	int initialized;
+	int refcnt;
+	int flags;
+	struct gendisk *disk;
+};
+
+static struct mbd_device mbd_dev[MAX_MBD];
+
+#define BD_INFO_SYNC   0
+#define BD_INFO_STATUS 1
+#define BD_INFO_BLKSZ  2
+#define BD_INFO_DEVSZ  3
+#define BD_INFO_CHANGE 4
+
+#define BOGUS_DISK_READ  116
+#define BOGUS_DISK_WRITE 117
+#define BOGUS_DISK_INFO  118
+
+static inline int
+MamboBogusDiskRead(int devno, void *buf, ulong sect, ulong nrsect)
+{
+	return callthru3(BOGUS_DISK_READ, (unsigned long)buf,
+			 (unsigned long)sect,
+			 (unsigned long)((nrsect << 16) | devno));
+}
+
+static inline int
+MamboBogusDiskWrite(int devno, void *buf, ulong sect, ulong nrsect)
+{
+	return callthru3(BOGUS_DISK_WRITE, (unsigned long)buf,
+			 (unsigned long)sect,
+			 (unsigned long)((nrsect << 16) | devno));
+}
+
+static inline int MamboBogusDiskInfo(int op, int devno)
+{
+	return callthru2(BOGUS_DISK_INFO, (unsigned long)op,
+			 (unsigned long)devno);
+}
+
+static int mbd_init_disk(int devno)
+{
+	struct gendisk *disk = mbd_dev[devno].disk;
+	unsigned int sz;
+
+	/* check disk configured */
+	if (!MamboBogusDiskInfo(BD_INFO_STATUS, devno)) {
+		printk(KERN_ERR
+		       "Attempting to open bogus disk before initializaiton\n");
+		return 0;
+	}
+
+	mbd_dev[devno].initialized++;
+
+	sz = MamboBogusDiskInfo(BD_INFO_DEVSZ, devno);
+
+	printk("Initializing disk %d with devsz %u\n", devno, sz);
+
+	set_capacity(disk, sz << 1);
+
+	return 1;
+}
+
+static void do_mbd_request(request_queue_t * q)
+{
+	int result = 0;
+	struct request *req;
+
+	while ((req = elv_next_request(q)) != NULL) {
+		int minor = req->rq_disk->first_minor;
+
+		switch (rq_data_dir(req)) {
+		case READ:
+			result = MamboBogusDiskRead(minor,
+						    req->buffer, req->sector,
+						    req->current_nr_sectors);
+			break;
+		case WRITE:
+			result = MamboBogusDiskWrite(minor,
+						     req->buffer, req->sector,
+						     req->current_nr_sectors);
+		};
+
+		if (result)
+			end_request(req, 0);	/* failure */
+		else
+			end_request(req, 1);	/* success */
+	}
+}
+
+static int mbd_release(struct inode *inode, struct file *file)
+{
+	struct mbd_device *lo;
+	int dev;
+
+	if (!inode)
+		return -ENODEV;
+	dev = inode->i_bdev->bd_disk->first_minor;
+	if (dev >= MAX_MBD)
+		return -ENODEV;
+	if (MamboBogusDiskInfo(BD_INFO_SYNC, dev) < 0) {
+		printk(KERN_ALERT "mbd_release: unable to sync\n");
+	}
+	lo = &mbd_dev[dev];
+	if (lo->refcnt <= 0)
+		printk(KERN_ALERT "mbd_release: refcount(%d) <= 0\n",
+		       lo->refcnt);
+	lo->refcnt--;
+	return 0;
+}
+
+static int mbd_revalidate(struct gendisk *disk)
+{
+	int devno = disk->first_minor;
+
+	mbd_init_disk(devno);
+
+	return 0;
+}
+
+static int mbd_open(struct inode *inode, struct file *file)
+{
+	int dev;
+
+	if (!inode)
+		return -EINVAL;
+	dev = inode->i_bdev->bd_disk->first_minor;
+	if (dev >= MAX_MBD)
+		return -ENODEV;
+
+	check_disk_change(inode->i_bdev);
+
+	if (!mbd_dev[dev].initialized)
+		if (!mbd_init_disk(dev))
+			return -ENODEV;
+
+	mbd_dev[dev].refcnt++;
+	return 0;
+}
+
+static struct block_device_operations mbd_fops = {
+      owner:THIS_MODULE,
+      open:mbd_open,
+      release:mbd_release,
+	/* media_changed:      mbd_check_change, */
+      revalidate_disk:mbd_revalidate,
+};
+
+static spinlock_t mbd_lock = SPIN_LOCK_UNLOCKED;
+
+static int __init mbd_init(void)
+{
+	int err = -ENOMEM;
+	int i;
+
+	for (i = 0; i < MAX_MBD; i++) {
+		struct gendisk *disk = alloc_disk(1);
+		if (!disk)
+			goto out;
+		mbd_dev[i].disk = disk;
+		/*
+		 * The new linux 2.5 block layer implementation requires
+		 * every gendisk to have its very own request_queue struct.
+		 * These structs are big so we dynamically allocate them.
+		 */
+		disk->queue = blk_init_queue(do_mbd_request, &mbd_lock);
+		if (!disk->queue) {
+			put_disk(disk);
+			goto out;
+		}
+	}
+
+	if (register_blkdev(MAJOR_NR, "mbd")) {
+		err = -EIO;
+		goto out;
+	}
+#ifdef MODULE
+	printk("mambo bogus disk: registered device at major %d\n", MAJOR_NR);
+#else
+	printk("mambo bogus disk: compiled in with kernel\n");
+#endif
+
+	devfs_mk_dir("mambobd");
+	for (i = 0; i < MAX_MBD; i++) {	/* load defaults */
+		struct gendisk *disk = mbd_dev[i].disk;
+		mbd_dev[i].initialized = 0;
+		mbd_dev[i].refcnt = 0;
+		mbd_dev[i].flags = 0;
+		disk->major = MAJOR_NR;
+		disk->first_minor = i;
+		disk->fops = &mbd_fops;
+		disk->private_data = &mbd_dev[i];
+		sprintf(disk->disk_name, "mambobd%d", i);
+		sprintf(disk->devfs_name, "mambobd%d", i);
+		set_capacity(disk, 0x7ffffc00ULL << 1);	/* 2 TB */
+		add_disk(disk);
+	}
+
+	return 0;
+      out:
+	while (i--) {
+		if (mbd_dev[i].disk->queue)
+			blk_cleanup_queue(mbd_dev[i].disk->queue);
+		put_disk(mbd_dev[i].disk);
+	}
+	return -EIO;
+}
+
+static void __exit mbd_cleanup(void)
+{
+	devfs_remove("mambobd");
+
+	if (unregister_blkdev(MAJOR_NR, "mbd") != 0)
+		printk("mbd: cleanup_module failed\n");
+	else
+		printk("mbd: module cleaned up.\n");
+}
+
+module_init(mbd_init);
+module_exit(mbd_cleanup);
+
+MODULE_DESCRIPTION("Mambo Block Device");
+MODULE_LICENSE("GPL");

--