From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dell-paw-3.cambridge.redhat.com ([195.224.55.237] helo=passion.cambridge.redhat.com) by pentafluge.infradead.org with esmtp (Exim 3.22 #1 (Red Hat Linux)) id 16fVuP-00048a-00 for ; Tue, 26 Feb 2002 00:55:57 +0000 From: David Woodhouse In-Reply-To: References: To: Vadim Khmelnitsky Cc: 'Ilguiz Latypov' , Mark Meade , linux-mtd@lists.infradead.org Subject: Re: DiskOnChip 2000 and Millenium support in GRUB bootloader Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Tue, 26 Feb 2002 01:06:48 +0000 Message-ID: <12174.1014685608@redhat.com> Sender: linux-mtd-admin@lists.infradead.org Errors-To: linux-mtd-admin@lists.infradead.org List-Help: List-Post: List-Subscribe: , List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: VadimK@m-sys.com said: > [Ilguiz] Vadim, should the Millennium SPL check sum include IPL? > [Vadim] No . IPL of Millennium chip copies 7K of data out of offset > 0x400 and calculates the checksum , which should be 0x55 . If it's > not 0x55 IPL returns to BIOS without executing SPL . What we want to achieve here is to install a tiny INT 19h handler which instead of bootstrapping the normal way, loads the Grub bootloader from the DiskOnChip IPL area and runs it. That tiny INT 19h handler and the code to install it ought to fit in the 512-byte IPL space on the Millennium, so I think we should be writing our own version of the IPL code on the Millennium, rather than using the existing IPL which tries to load a whole 8KiB of SPL. On the DiskOnChip 2000, the IPL in ROM loads the whole 8KiB, but still we only use 512 bytes for our own INT 19h-installer code, and that later reloads the whole of Grub from the flash. You can see this code at ftp://www.uk.linux.org/pub/people/dwmw2/mtd/cvs/mtd/grub/doc_stage1.S ftp://www.uk.linux.org/pub/people/dwmw2/mtd/cvs/mtd/grub/doc_stage1b.S Some documentation is in the 'README' file in the same directory. -- dwmw2