Booting GRUB on the DiskOnChip 2000 and Millennium

1. Save DiskOnChip contents, Bad Block Table

1. Get the latest version of the DOS based M-Systems DiskOnChip Software Utilities from www.m-sys.com. If desired, the GETIMAGE utility can be used to save the current contents of the DoC:

   getimage /win:xxxx <filename>

   (where xxxx is the DoC base memory address in hex (window), for example: /win:d000)

2. Save the Bad Block Table! Before attempting to boot with GRUB, make sure that the bad block table has been saved. Doing this insures you can always restore the BBT in the event of the DoC being corrupted or completely erased:

   dformat /win:xxxx /noformat /log:<filename.txt>

   This creates a text file containing a list of all the bad blocks on the DoC. The dformat "uselog" option may be used to restore the BBT if needed:

   dformat /win:xxxx /noformat /uselog:<filename.txt>

   Note: the "win:xxxx" parameter tells dformat the segment address, in hex, where your DiskOnChip resides in memory. If it is not specified, it will search addresses 0xC8000 to 0xE0000. The segment address is multiplied by 16 to get the physical address -- for example, if your DoC is at 0xD4000, use "/win:D400".

3. The DINFO utility is useful for displaying some detailed information about the DoC and the bad block table:

   dinfo dinfo /BBT

2. Get the latest MTD sources

1. Reboot into Linux, and get the latest MTD sources from infradead.org:

   mkdir grub-doc cd grub-doc cvs -d :pserver:anoncvs@cvs.infradead.org:/home/cvs login (password = anoncvs) cvs -z3 -d :pserver:anoncvs@cvs.infradead.org:/home/cvs co mtd

   Alternatively, there are daily CVS snapshots available as .tar.bz2 files at ftp.uk.linux.org.

   Patch a kernel, select the various DiskOnChip MTD options as specified above, and build a new kernel. Reboot.

3. Patch GRUB

1. Get the latest grub sources (CVS) -- just hit enter when prompted for password:

   cvs -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/grub login cvs -z3 -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/grub co grub

2. Patch GRUB with DiskOnChip updates:

   cd grub patch -p0 -i ../mtd/patches/grub-2003-01-08-doc.patch

   This patch may fail on the "ChangeLog" or "AUTHORS" file, but all other files should patch correctly. Make sure that the files in stage1 and stage2 directories patch correctly.

4. Build GRUB

1. IMPORTANT: The GRUB code currently requires automake version 1.5 and autoconf version 2.53. On some systems, this can be specified by exporting WANT_AUTOMAKE_1_5=1 and WANT_AUTOCONF_2_5=1.

   aclocal && automake --add-missing && autoconf

   If there are any error messages here, they are probably due to version incompatibilities with automake and/or autoconf.

2. Configure GRUB with the following options (for example):

   ./configure --enable-diskonchip-mil \ --enable-diskonchip-biosnetboot \ --enable-diskonchip-ctrlbypass \ --enable-ext2fs \ --disable-ffs --disable-xfs --disable-jfs --disable-vstafs \ --disable-reiserfs --disable-minix --disable-fat

   If you have a DoC 2000, use --enable-diskonchip-2000 instead of --enable-diskonchip-mil. README_DiskOnChip in the grub directory has more information regarding the ./configure options, and also some details on the DoC booting process.

   Selecting --enable-diskonchip-biosnetboot causes the GRUB/DoC code to hook INT 18H, which is historically known as the "BASIC interrupt" or "Diskless Boot Interrupt". Using this option with the DoC on a PC is useful because you change easily change the boot sequence back to the hard drive when needed. Selecting this option in many BIOSes usually involves changing the first boot device to "NETWORK".

   If the BIOS does not have a NETWORK boot option, disable the "biosnetboot" option. Instead of using INT 18H, the GRUB/DoC code will hook the INT 19H (bootstrap) handler. On my PC, taking over the bootstrap handler overrides any boot sequence options in the BIOS setup. The downside of using INT 19H is that a misconfigured DoC can render your machine unbootable. For this reason, the --enable-diskonchip-ctrlbypass option is highly recommended until you are sure that the DoC boots correctly. When the CTRL key is held during booting, this option will bypass the DoC entirely by restoring the original bootstrap handler.

   This is obviously preferable to the other option -- physically removing the DoC (or eval-board) to get the PC to boot from the hard drive again. In that case, it is necessary to "hotplug" the DoC *after* the PC has booted, into a powered up eval board.

3. Now that all the DoC options are set, simply type:

   make

   If the build is successful, there should be a file named grub_firmware in the /stage1 directory.

5. Copy GRUB to DOC

1. Copy the grub_firmware to a floppy diskette, or to a partition that is accessable by DOS. Reboot into DOS.

2. Use DFORMAT to load GRUB and also to format the DiskOnChip:

   DFORMAT /win:xxxx /BDKF0:grub_firmware

   This utility automatically adjusts for the size of grub_firmware, so specifying the length of the boot image file is not necessary. There is another DFORMAT option that can be used to leave a little extra room for booting firmware in the future, if desired:

   DFORMAT /win:xxxx /BDKF0:grub_firmware /BDKL0:<size>

6. Turn off PC

The PC should be turned off (not just rebooted) after running DFORMAT. This may not be necessary on all types of hardware, but it was required on my PC. From M-Systems application note DOC-044:

The boot block is implemented as a XIP block located between the flash media and the system bus. After the DiskOnChip Millennium powers-on, or when its reset signal is negated, the contents of the first page of flash memory are copied into the Boot Block.

7. Change Boot Sequence

If you used the "biosnetboot" option when configuring Grub, you'll need to change the boot sequence: In the BIOS setup, select NETWORK (or NIC, or its equivalent) as the first boot device. If "biosnetboot" was not used, no BIOS setup changes should be needed.

8. Verify GRUB boot

1. The PC should now boot from the DiskOnChip. The BIOS may say something like Searching for boot record from Network.... The first DoC messages displayed should be:

   DoC found (BIOS detected the DoC Extension) DoC Mil D000 (BIOS jumped to DoC boot interrupt) E698 (DoC Chip ID and Manufacturer code, for example) Grub: (Jumping to stage2) DiskOnChip Millennium found at d0000 (first stage 2 message)

   When the boot process completes, there should be a "grub>" command line. We haven't installed a kernel or a "menu.lst" file on the DiskOnChip yet, so this step is just to verify that the grub_firmware was installed correctly, and that the DoC will boot.

   If you are already using GRUB on a hard drive, it's possible that the DoC GRUB will locate and use the menu.lst file in the /boot/grub directory on the drive. In this case, you should have the GRUB boot selection menu as usual -- GRUB booted from the DoC, but loaded the boot options from the hard drive.

2. At this point, you can either reboot again, change the boot sequence back to IDE (or whatever), and boot back into Linux. Alternatively, if you know where your kernel and root filesystem is on the hard drive, simply type something like:

   kernel (hd0,0)/vmlinuz-doc root=/dev/hda2 boot

   If Grub doesn't boot, the informational messages may help determine why, or where the failure occurred. Remember, if the --enable-diskonchip-ctrlbypass option was specified, holding the ctrl-key during boot should bypass the DoC entirely.

9. Verify DiskOnChip FAT Partition

1. You should now be able to partition the DiskOnChip, and create the appropriate file systems. The DFORMAT command used earlier should have created one FAT partition on the DoC. To verify this, try:

   mkdir /mnt/doc mount /dev/nftla1 /mnt/doc umount /mnt/doc

   If the mount is not successful, you might need to run the ./MAKEDEV script to create the proper device MTD device entries in the /dev directory. This MAKEDEV utility is available in the MTD archives.

2. The other common cause of failure at this point is the use of earlier MTD versions -- for instance, a unmodified 2.4.18 kernel will not be successful in mounting this FAT partition. If the "dmesg" output has a message that says something like "we don't support a unit size factor != 1", then you definitely need to update the MTD code in the kernel.

10. Create ext2 partition on the DiskOnChip

1. To boot directly from the DoC, we'll need to create an ext2 partition, and install the kernel and GRUB menu.lst file:

   fdisk /dev/nftla d 1 <enter> (delete fat partition created by DFORMAT) n p 1 <enter> <enter> (create new primary partition, using defaults) w (save new partition info) mke2fs /dev/nftla1 mount -t ext2 /dev/nftla1 /mnt/doc mkdir -p /mnt/doc/boot/grub cp /boot/vmlinuz-doc /mnt/doc/boot

2. Now create a "menu.lst" file in /mnt/doc/boot/grub. This file should contain the following:

   timeout 10 default 0 title DiskOnChip Boot kernel (dc0,0)/boot/vmlinuz-doc root=/dev/hdaX

   Where hdaX is the hard drive that contains your root Linux filesystem. You could also add another entry to the file to boot directly from the hard drive, if desired.

3. Umount the /mnt/doc directory, and reboot the PC.

4. At this point, the PC should boot entirely from the DoC, and attempt to mount the root filesystem on your hard drive. If this works, the next step to a fully self-contained boot is to create a full root filesystem or ramdisk on the DoC. Once that has been done, change the "root=/dev/hdaX" option to "root=/dev/ntfla1".

1. Verify TrueFFS Driver Version

1. The newer versions (5.0 or later) of the M-Systems DOC firmware will not work correctly with the MTD drivers in 2.4.18. An earlier version (4.2) is required.

   Using version 4.2 of the DOS TrueFFS utilities available from M-Systems (www.m-sys.com), verify that the DOC is recognized, and that the firmware version is 4.2:

   dinfo

2. If the firmware version is 5.0 or later, run the DFORMAT utility:

   dformat /win:xxxx /s:doc42.exb

2. Save the Bad Block Table (BBT)

1. See step #1, in Section #1, above.

3. Get the latest MTD sources

1. See step #2, in Section #1, above. Later steps in this procedure will be much easier if the the MTD/DiskOnChip portions are compiled as modules, rather than built-in to the kernel. If the modules are built-in, make sure to reboot after each each subsequent step.

4. Patch and Build GRUB

1. Follow steps #3 and #4 in Section #1, above.

5. Copy GRUB to DOC

1. Load the appropriate MTD modules, and run the doc_loadbios utility to copy the Grub firmware to the DiskOnChip:

   insmod mtdcore insmod mtdchar insmod docecc insmod doc2000 insmod docprobe cd mtd/util make doc_loadbios ./doc_loadbios /dev/mtd0 grub_firmware

   If an error is reported regarding /dev/mtd0, you might need to run the ./MAKEDEV script to create the proper device MTD device entries in the /dev directory.

6. NFTL Format

1. Running nftl_format under Linux is analogous to the DFORMAT utility under DOS

   ./nftl_format /dev/mtd0 98304

   The "start offset" of 98304 insures that the grub_firmware is not overwritten. This offset should be larger than the size of the grub_firmware file, and probably should be a multiple of 16k.

   As nftl_format runs, there should be notices about "skipping bad zone (factory marked)". The bad zone values should be identical to the values in the file created in step #2.

2. There should be no need to run the "eraseall" utility. This can be dangerous as it will complete erase the DoC, including the bad block table -- saving the BBT as described earlier is highly recommended.

7. Create ext2 partition on the DiskOnChip

1. To boot directly from the DoC, we'll need to create an ext2 partition, and install the kernel and GRUB menu.lst file:

   insmod nftl fdisk /dev/nftla n p 1 <enter> <enter> (create new primary partition, using defaults) w (save new partition info) rmmod nftl insmod nftl mke2fs /dev/nftla1 mount -t ext2 /dev/nftla1 /mnt/doc mkdir -p /mnt/doc/boot/grub cp /boot/vmlinuz-doc /mnt/doc/boot

   Note that the nftl module is reloaded *after* doing the fdisk. This is done to insure that the new partition information is recognized by the nftl module -- if this isn't done, very bad things may occur.

2. There is a patch available that adds an IOCTL command to the nftl driver, and also a modification to the nftl_format command. This would make it unnecessary to unload the nftl module during nftl_format and after fdisk. If this patch has not already been applied to the MTD CVS, it can be found on the Linux-MTD Mailing List.

8. Create menu.lst file

Create a "menu.lst" file, as described step #10 in section #1, above.

9. Reboot with GRUB

After completing steps #1-#8, it may be necessary to turn off the PC before booting Grub from the DiskOnChip. See Step #5 in section #1 for the details.