Hello Heiko,
On Wed, Aug 11, 2010 at 1:56 AM, Heiko Schocher hs@denx.de wrote:
Hello Ben,
Thanks for trying this patches!
My pleasure! Thank you for doing the hard work.
Ben Gardiner wrote:
On Fri, Aug 6, 2010 at 12:44 PM, Ben Gardiner bengardiner@nanometrics.ca wrote: I did get an openocd debugger going with uboot on the da850 (see the
Good!
:)
It looks like execution goes off into the weeds at arch/arm/cpu/arm926ejs/start.S:294
288 ldr r2, _board_init_r 289 sub r2, r2, r0 290 add r2, r2, r7 /* position from board_init_r in RAM */ 291 /* setup parameters for board_init_r */ 292 mov r0, r5 /* gd_t */ 293 mov r1, r7 /* dest_addr */ 294 /* jump to it ... */ 295 mov lr, r2 296 mov pc, lr
board_init_r == 0xc10804e4 , $r0 == 0xc1080000 and $r7 == 0x7fff0000
r7 == 0x7fff0000 seems totally wrong to me ... this would result that relocated board_init_r start @0x7fff04e4 ... thats not in RAM!
It turns out that the region I have assigned to CONFIG_SYS_SDRAM_BASE (0x80000000) was reading as all 0' so even though get_ram_size was returning 128M to dram_init, storing it in gd->ram_size didn't work. Ditto for CONFIG_SYS_SDRAM_BASE set to 0xffff0000. I think this means that only the DDR is available when UBL hands-off to u-boot.
Why this values for CONFIG_SYS_SDRAM_BASE? They cannot work! As I see in the include/configs/da850evm.h file:
#define PHYS_SDRAM_1 DAVINCI_DDR_EMIF_DATA_BASE /* DDR Start */
so, RAM starts @DAVINCI_DDR_EMIF_DATA_BASE (=0xc0000000)
-> CONFIG_SYS_SDRAM_BASE should/must be @0xc0000000
I was trying to "find another (not dram) area in which we can use for an intial stack" as you suggested in 4C5B9DB5.7020009@denx.de. I think I must have misunderstood what needed to be changed to accomplish this.
(Better would be a non RAM location for initial stack, but I don;t know if we have some area on this cpu for that)
8k@0xffff0000 is an 'Arm local RAM' region and 128k@0x80000000 is a 'Shared RAM' region. But neither seemed to be read as anything other than 0x0000 when I was debugging. I think there would need to be some magic writes first to enable these regions.
Can you try
http://git.denx.de/?p=u-boot/u-boot-testing.git;a=shortlog;h=refs/heads/arm-...
- remove in include/configs/da850evm.h
line 42: #define CONFIG_SKIP_RELOCATE_UBOOT /* to a proper address, init done */
?
If it don;t work, can you make a breakpoint in arch/arm/cpu/arm926ejs/start.S relocate_code and provide a register dump? And can you find out whats stored in gd->ram_size?
Most definitely. I'll get back to you shortly.
Best Regards, Ben Gardiner
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