Benjamin Herrenschmidt wrote: > - There is _one_ important point to keep in mind, but that has always >been true: None of this work before MMU_init(), > >
This is very true and raises a couple issues that we should fix while we're at it: 1) There are progress calls in MMU_init which will try to access the uart before its possible to create a mapping to the uart's regs (assuming you don't make a hack to map them and that you set up ppc_md.progress in your platform_init routine). We should either get rid of those calls in MMU_init, provide an acceptable way to make temporary pre-MMU_init mappings, or make sure nobody sets up ppc_md.progress until ioremap is working (and also get rid of the calls in MMU_init b/c they're never used). 2) Some firmwares don't provide any info on how much memory is in the system but MMU_init needs to know that. So the platform code has to read the SPD from the mem sticks via i2c, read the mem ctlr, or read a board reg that has the info. All of those require access to hw regs before or during MMU_init. I should be able to get rid of this one by figuring out the amount of memory in the bootwrapper and passing it in to the kernel. I am assuming that all the boards with this problem use the bootwrapper. I think that's a safe assumption but I'll have to verify. BTW, these are the reasons that I made that set_bat hack that Dan is so fond of. :) I'll get rid of that hack but I need an answer to 1) first. Mark
