HELP! Memory mapping and address space doubts

[Jose França (Ext_GTBC)]

Hello u all!

	I need to clarify some aspects of the memory management in ppc linux and i hope that you could help me.
	Lets imagine we have a mpc8272 based board with 3 devices A, B and C.In the bootloader (in my case, i use u-boot), i configured the BRx and Orx so that A has base address X, B has base address Y and C has base address Z. My first doubt arrises here: what address should i use? Being SDRAM base address 0x00000000 and kernel base address 0xC0000000, where will i put these devices mapped on? Above 0xC0000000 or in between the end of physical memory and 0xC0000000? Do i really need to configure the BAT registers in u boot?
	In linux 2.4 kernel, we have ppc_md.setup_io_mappings to map address blocks into the BAT registers... As i observed in the kernel source tree examples, we must map CPM (why?). And what about the other devices A, B and C? How will i setup them in this case and what addresses i can use? Above 0xC0000000 or in between the end of physical memory and 0xC0000000? Is the SDRAM included?

	Thanks in advance to all contributions! All of them will be most welcomed!





Best regards,
Filipe