From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geir Thomassen Date: Wed, 12 Feb 2003 19:40:27 +0100 Subject: [U-Boot-Users] Memory layout on PXA Message-ID: <3E4A951B.5030309@in.fer.no> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de I am porting u-boot to a custom PXA255 board. Just a quick check, to see if I understand the code correctly: 1) u-boot is copied from flash into memory at TEXT_BASE (typ. 0xA3000000 on PXA). 2) The stack is below the u-boot code. From cpu/xscale/start.S, it looks like the stack is at TEXT_BASE - CFG_MALLOC_LEN - 12. I think the stack grows toward lower addresses on arm, is this correct ? 3) Memory for malloc() is supposed to be after the u-boot code (including initialized and initialized data) at address armboot_real_end. If I understand the code correct, it points 0xbadc0de. Some time, it has been set to armboot_end + CONFIG_STACKSIZE in cpu/xscale/cpu.c, but the code for doing so have been commented out (both in 0.2.0 and in CVS). There is room for putting the heap between the stack and the u-boot code ... Sooo, if I understand this correct, this is a mess. How should it be done ? Are there any good reasons for a particular memory layout on PXA ? BTW: Does u-boot run "out of the box" on any PXA hardware, I don't understand how it could unless the hardware have RAM at 0xBADC0DE .. -- Geir