From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Dyer Date: Mon, 22 Aug 2005 18:43:15 -0500 Subject: [U-Boot-Users] RFC: U-Boot Environment support in SystemAce Compact FLASH In-Reply-To: <20050822205623.BD248353D18@atlas.denx.de> References: <20050822205623.BD248353D18@atlas.denx.de> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 8/22/05, Wolfgang Denk wrote: > In message you wrote: > > > > I have completed the initial port of U-Boot to a custom PPC405/VirtexII > > Pro FPGA board and I am starting to look at ways to store the U-Boot > > environment in the CF card used for FPGA configuration by the Xilinx > > SystemAce. > > Please re-read the archives why this is not as trivial as it may seem. > > > I am leaning toward the approach of adding DOS FAT write support and > > adjusting the initial U-Boot environment to provide sufficient stack space > > This won't help you much. In the first step, you would have to modify > the whole CF and DOS FAT code such that it works while running from > flash. This is a non-trivial task, and I don't intend to accept such > modifications for inclusion in the publich tree. > Does a system ace CF card have a partition table? Maybe you could make a special partition on the CF for this type of info. You would need a sector read routine and code to parse the partition table to index into the environment sectors. You would probably need some ram available (or at least a bunch of registers) to pull this off. Another option might be to store the environment stuff as data to be loaded into an accessible block ram on fpga power-up. I haven't looked at how system ace handles this sort of thing. Are the block ram contents stored in separate files on the CF? -- Hardware, n.: The parts of a computer system that can be kicked.