On Wed, Aug 06, 2003 at 07:45:32PM -0600, M. Warner Losh wrote: > Well, I don't know. The PC Cards that we have in the system are > mapped into the I/O and memory ranges traditionally reserved for the > ISA bus. In ISA systems, this made sense because pccard was attached > to pcic was attached to isa. However, now we have situations where > pccard is attached to cbb which is attached to pci. There may be a > isab device with isa bus hanging off of it that makes the relationship > between the pccard devices cousins rather than nephews in the tree. > And there isn't any harm from that. Wouldn't this be a similar > situation?
The flash I'm talking about is not pccard related. Sorry if I gave that impression. The SC520 has onboard support to control 3 flash chips. The board I have has 2 Mb NOR flash chip containing BIOS plus a DOS file system (at the moment) where I keep a copy of an etherboot executable. The board also has a 64Mb NAND flash chip which I've written a FreeBSD UFS image into. Our standard bootloader happily loads the kernel from that. Now I need to get a flash driver working for the root file system. I've got an existing read-only flash driver that I used to use on an Intel 386EX board, but that had the entire flash chip memory mapped. This new board maps the NAND flash in 4K pages. > : >From my reading of the AMD docs, only the CPU core is identifiable > : via the CPUID instruction. The docs say that the first two bytes of > : the MMCR are the REVID and those can be used to "identify the device > : itself". The second byte is set to zero to "identify the product as > : the ElanSC520 microcontroller". So if you know the MMCR is there, > : you can go to that byte and get confirmation! Thanks AMD. It seems > : that the discovery via the host to PCI bridge is the only reliable > : way to go. > > Can you send me a URL for that document? I thought I understood > things, but making sure by reading it would sure help. This URL lists the relevent docs: <http://www.amd.com/us-en/ConnectivitySolutions/ProductInformation/0,,50_2330_8634_8635%5E8641,00.html> The ones you want are the "ElanSC520 Users Manual" and "ElanSC520 Register Set Manual" >From what I can see, all the SC520 specific things are accessed via the MMCR registers. The direct mapped registers are only for PC/AT compatible stuff, so they are of no help. Then there are the PCI things. To be PCI compatible, AMD *had* to give the host bridge a device ID. That is the _only_ thing given an ID. > But adding it as a child of nexus in the host bridge code wouldn't > make it probe any earlier. To do that you'd need to make it a true > child of nexus with a identify routine that would go out and try to > find the host bridge at a certain address and use the right kind of > bridge there to add the device. You could then map the mmcr space to > a convenient location, and then dole it out to child drivers such that > the bus_space macros would do the right thing. Since it is memory > mapped, this would be relatively easy to do. This would also allow > you to make it known earlier in the boot process. This is also very > much analygous to what pccard and cardbus does. You wouldn't have the > problems that we have with picking resources in the cardbus bridge > code because it looks like the mmcr is at a fixed address (either by > design of the chip or by phk's big stick). > > If you'd like, I can sketch out in code what I'm trying to say in > words here. If you have time, I'd be interested. This is a hot topic for me because it is exactly where I'm up to. I have everything else working on the board. -- John Birrell _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
