In message <4408A1D3.8010506 at ovro.caltech.edu> you wrote: > > > Still not right. Even the physical memory is software settable. What > > matters is what chip-select things are hooked up to, and then map those > > chip selects correctly (size, base address, access with and so on) > > Thats what I meant with 'redefined in hardware'. But yes, redefined > up to the limit of the wiring on the board of course (chip-selects > and bus widths). That's where having the board schematic is > invaluable.
You don't get it. You can map - for example - your flash to physical address 0x0000 or 0x04000000 or 0x40000000 or 0xFFF00000 as you like - without any changes to the hardware, and without using the MMU. Mind: that's all *physical* addresses. > manual for the 440EP Yosemite board), and then setup U-Boot and > Linux to program the TLBs to translate to those same addresses. No. U-Boot does not use the MMU. > when I booted Linux, I took a look and found that on the whole, Linux > didn't touch too much of the things setup by U-Boot, i.e., the > responsibility for setting up the Linux environment was mainly > the job of the bootloader. Wrong again. Linux completely re-initializes the whole memory management. > So, if I had a board with a custom bootloader, I would be > concerned that the bootloader might not know enough about > Linux, to setup the hardware correctly. > > Does that sound right? No, it's wrong. Best regards, Wolfgang Denk -- Software Engineering: Embedded and Realtime Systems, Embedded Linux Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de "Language shapes the way we think, and determines what we can think about." - B. L. Whorf
