[U-Boot] Unable to boot evb-ast2500

[Cédric Le Goater]

On 08/06/2018 05:25 AM, Joel Stanley wrote:
> Hello,
> 
> I am attempting to boot evb-ast2500 in Qemu before flashing it to a
> system. It doesn't get past the DRAM step, due to getting stuck
> endlessly looping in some libfdt code.
> 
> With some debugging turned on, I get this:
> 
> OF: translating address: 0040781e
> OF: parent translation for: 00000000
> OF: one level translation: 0040781e
> OF: parent translation for: 00000000
> OF: one level translation: 0040781e
> OF: translating address: 00206e1e
> 
> 
> U-Boot 2018.09-rc1-00096-gbb694d4e898b-dirty (Aug 06 2018 - 12:27:22 +0930)
> 
> Model: Aspeed BMC
> DRAM:  OF: translating address: 00006e1e
> OF: translating address: 00026e1e
> OF: translating address: 0050781e
> OF: parent translation for: 00000000
> OF: one level translation: 0050781e
> OF: parent translation for: 00000000
> OF: one level translation: 0050781e
> Watchdog timer expired.
> 
> And then the watchdog causes the system to reboot. The build is master
> as of gbb694d4e898b, with the addition of some #define DEBUG.
> 
> I don't think this is a qemu issue. If it is, I can work on fixing
> qemu, but I need some help on understanding what u-boot is doing.

The sdram driver in U-Boot uses the watchdog1 and the SCU power 
reset register to reset the SDRAM controller. Our QEMU emulation
is not precise enough I think.

C.

> 
> There's a big pause before the U-Boot banner, and again after showing
> 'DRAM: 'before getting any of the OF messages. If I get gdb to show me
> a backtrace at this point:
> 
> #0  0x0001e858 in __fswab32 (x=<optimised out>) at
> include/linux/byteorder/swab.h:114
> #1  fdt_offset_ptr (fdt=fdt at entry=0x39370, offset=offset at entry=6444,
> len=len at entry=4)
>     at lib/libfdt/../../scripts/dtc/libfdt/fdt.c:86
> #2  0x0001e9b4 in fdt_next_tag (fdt=fdt at entry=0x39370,
> startoffset=startoffset at entry=6440,
>     nextoffset=0x1e726d44, nextoffset at entry=0x1e726d3c)
>     at lib/libfdt/../../scripts/dtc/libfdt/fdt.c:120
> #3  0x0001eae4 in fdt_next_node (fdt=fdt at entry=0x39370, offset=6440,
> depth=0x1e726d5c,
>     depth at entry=0x1e726d54) at lib/libfdt/../../scripts/dtc/libfdt/fdt.c:176
> #4  0x000205cc in fdt_supernode_atdepth_offset (fdt=0x39370,
> nodeoffset=14748, supernodedepth=0,
>     nodedepth=0x0 <_start>) at lib/libfdt/fdt_ro.c:443
> #5  0x00011608 in ofnode_get_parent (node=..., node at entry=...) at
> include/dm/ofnode.h:94
> #6  0x000113dc in regmap_init_mem (node=..., mapp=0x0 <_start>,
> mapp at entry=0x1e726dbc)
>     at drivers/core/regmap.c:63
> #7  0x000014e0 in ast2500_sdrammc_ofdata_to_platdata (dev=0x1e7273c4)
> at include/dm/read.h:38
> #8  0x0000fc88 in device_probe (dev=dev at entry=0x1e7273c4) at
> drivers/core/device.c:399
> #9  0x000108c0 in uclass_get_device_tail (dev=0x1e7273c4,
> ret=<optimised out>, devp=0x1e726e0c)
>     at drivers/core/uclass.c:397
> #10 0x00010900 in uclass_get_device (id=id at entry=UCLASS_RAM,
> index=index at entry=0,
>     devp=0x1e726e0c, devp at entry=0x1e726e04) at drivers/core/uclass.c:413
> #11 0x00001ab0 in dram_init () at arch/arm/mach-aspeed/ast2500-board.c:69
> #12 0x0001b834 in initcall_run_list
> (init_sequence=init_sequence at entry=0x29344 <init_sequence_f>)
>     at lib/initcall.c:30
> #13 0x0000854c in board_init_f (boot_flags=<optimised out>) at
> common/board_f.c:900
> #14 0x00000664 in _main () at arch/arm/lib/crt0.S:86
> 
> Cheers,
> 
> Joel
> 
> --
> 
> To reproduce in qemu, build qemu master for ARM:
> 
> git://git.qemu-project.org/qemu && cd qemu
> ./configure --target-list=arm-softmmu
> make
> 
> build a 32MB image from u-boot.bin:
> 
> dd if=/dev/zero of=test.img bs=1M count=32
> dd if=u-boot.bin of=test.img conv=notrunc
> 
> boot it:
> 
> arm-softmmu/qemu-system-arm -M ast2500-evb -m 512 -nographic -drive
> file=test.img,format=raw,if=mtd -serial stdio -monitor pty
>