-----Original Message----- From: ebiederm@xmission.com [mailto:ebiederm@xmission.com] Sent: Friday, December 01, 2006 1:15 PM
Peter Stuge stuge-linuxbios@cdy.org writes:
On Fri, Dec 01, 2006 at 11:19:16AM -0800, Greg KH wrote:
Well, earlyprintk will not work, as you need PCI up and running.
Not all of it though. LinuxBIOS will probably do just enough PCI setup to talk to the EHCI controller and use the debug port _very_ soon after power on.
Right. For LinuxBIOS not a problem for earlyprintk in the kernel somethings might need to be refactored. The challenge in the kernel is we don't know at build to how to do a pci_read_config...
early_pci_read_config? Otherwise printk will come too late, and will not get output before pci bus ops is set.
The other hard part early in the kernel is the fact that the bar is memory mapped I/O. Which means it will need to get mapped into the kernels page tables.
several entries to map 0xfc000000 ( PCI IO mem range) in page table in head.S?
YH
-
Lu, Yinghai