i.MX53/compact 7 MMU problem

c393 — Wed, 03 Oct 2012 18:14:03 GMT

I have a custom i.MX53 board running compact 7. The BSP is cloned from IMX53 ARD Mobility. I am booting from SDIO, boots until it enables the MMU and starts to execute at the virtual address. At that point it is in the weeds. The IMX53 ARD mobility bsp had 1GB of DDR3 RAM my board has 512MB of DDR3 RAM. In the project I have environment variable "imgram512" set. Any suggestions on why it gets lost when switching to virtual world?

Area in startup.s that program gets lost:

ACTIVATEMMU

; The 1st Level Section Descriptors are setup. Initialize the MMU and turn it on.

;

mov r1, #1

mcr p15, 0, r1, c3, c0, 0 ; Set up access to domain 0.

mov r0, #0

mcr p15, 0, r0, c8, c7, 0 ; Flush the instruction and data TLBs.

mcr p15, 0, r1, c7, c10, 4 ; Drain the write and fill buffers.

mrc p15, 0, r1, c1, c0, 0 ; Read control register

orr r1, r1, #0x1 ; Enable MMU.

orr r1, r1, #0x1000 ; Enable IC.

orr r1, r1, #0x4 ; Enable DC.

ldr r4, =VirtualStart ; Get virtual address of 'VirtualStart' label.

cmp r4, #0 ; Make sure no stall on "mov pc,r4" below.

mcr p15, 0, r1, c1, c0, 0 ; Enable MMU and caches

mov pc, r4 ; Jump to virtual address

nop

ALIGN

; We are now running virtual address space.

VirtualStart

additional information address of mov pc, r4 0x7000_1608 , address of VitualStart 0x8004_2608

Re: i.MX53/compact 7 MMU problem

JerryZeng — Tue, 09 Oct 2012 03:39:46 GMT

Your issue has nothing to do with 512M/1G memory. If your DDR init script is correct, such different DDR configuration will only impact NK not eboot. And since you have already set IMGRAM512, even in NK there should be no problem with 512M DDR.

This issue is also not a MMU problem. MMU is a standard unit in the ARM core, as long as you reuse all the ARM init code from original MX53 ARD BSP, MMU should work without any problem.

Your issue should be configuration issue. I don't remember the exact virtual address, but I feel your virtual address has a 4k offset (0x70001608 vs 0x80042608). Did you change anything in bib files (eboot.bib/config.bib) or other files which may impact the virtual address configuration in your BSP?

Since you have the debug tool to trace the code, another suggestion is that you can try Freescale's default BSP on MX53 SMD or ARD board (if you have these boards :smileyhappy:) and check the physical address / virtual address to quick confirm if this is the cause of your issue.

i.MX Processorsのトピックi.MX53/compact 7 MMU problem

i.MX53/compact 7 MMU problem

Re: i.MX53/compact 7 MMU problem