[U-Boot] Help Request - Command parsing, find_cmd (), possible linker script problem

[Graeme Russ <graeme.russ@gmail.com>]

Hi All,

So far I have my sc520 board booting into main_loop (), DRAM configured
and serial ports working. Now I seem to be stuck on getting commands
to execute (even help). Using printf() I have traced my problem into
find_cmd (). I added the following into find_cmd() just before the for
loop:

printf ("Searching for Command '%s'\n", cmd);
printf ("Command Table Start : %08lx\n", (ulong)&__u_boot_cmd_start);
printf ("Command Table End   : %08lx\n", (ulong)&__u_boot_cmd_end);
printf ("sizeof(int)         : %x\n", sizeof(int));
printf ("sizeof(cmd_tbl_t)   : %x\n", sizeof(cmd_tbl_t));

and

printf ("Checking : %08lx\n", (ulong)cmdtp);

just inside the for loop

The output is (there are a few other printf()'s leadinf up to
find_cmd () as well):

boot > help

[RUN_COMMAND] cmd[00400ccc]="help"
[PROCESS_SEPARATORS] help
token: "help"

Processing Macros...
[PROCESS_MACROS] INPUT len 4: "help"
[PROCESS_MACROS] OUTPUT len 4: "help"
Extracting Arguments...
parse_line: "help"

parse_line: nargs=1
Looking up Command...
Searching for Command 'help'
Command Table Start : 0000053e
Command Table End   : 00000870
sizeof(int)         : 4
sizeof(cmd_tbl_t)   : 18
Checking : 0000053e
Checking : 00000556
Checking : 0000056e
.
.
.
Checking : 00000856
Checking : 0000086e
Checking : 00000886
Checking : 0000089e
Checking : 000008b6

There are a few weird things going on...

a) sizeof(cmd_tbl_t) is 18, but the loop is incrementing by 24 (I would
have thought a 4 byte alignment would push it to 20 maybe)

b) The loop never completes since cmdtp never actually equals
&__u_boot_cmd_end

c) The bootrom flash is mapped to 0x38000000. The flash is 512k with
U-Boot image being 256k puts U-Boot at 0x38040000. I have adjusted
TEXT_BASE = 0x38040000 in config.mk and adjusted u-boot.lds (see
full u-boot.lds below) (for those that don't know the AMD sc520, the
boot flash memory region can be 'mapped' to wherever you want it,
and I have confirmed the mapping be dumping the address of the
last_stage_init() function which resides at 0x38046d57 - right were
I expect it). I would, therefore, expect the command table to live
somewhere in 0x38040000 - 0x3807ffff

Can anyone point me an a rough direction to look? Any help at all
would be greatly appreciated

Regards,

Graeme

u-boot.lds:

OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
OUTPUT_ARCH(i386)
ENTRY(_start)

SECTIONS
{
	. = 0x38040000;		/* Where bootcode in the flash is mapped */
	.text  : { *(.text); }

	. = ALIGN(4);
	.rodata : { *(.rodata) *(.rodata.str1.1) *(.rodata.str1.32) }

	. = 0x400000;	                    /* Ram data segment to use */
	_i386boot_romdata_dest = ABSOLUTE(.);
	.data : AT ( LOADADDR(.rodata) + SIZEOF(.rodata) ) { *(.data) }
	_i386boot_romdata_start = LOADADDR(.data);

	. = ALIGN(4);
	.got : AT ( LOADADDR(.data) + SIZEOF(.data) ) { *(.got) }
	_i386boot_romdata_size = SIZEOF(.data) + SIZEOF(.got);


	. = ALIGN(4);
	_i386boot_bss_start = ABSOLUTE(.);
	.bss (NOLOAD) : { *(.bss) }
	_i386boot_bss_size = SIZEOF(.bss);


	/* 16bit realmode trampoline code */
	.realmode 0x7c0 : AT ( LOADADDR(.got) + SIZEOF(.got) ) { *(.realmode) }

	_i386boot_realmode = LOADADDR(.realmode);
	_i386boot_realmode_size = SIZEOF(.realmode);

	/* 16bit BIOS emulation code (just enough to boot Linux) */
	.bios 0 : AT ( LOADADDR(.realmode) + SIZEOF(.realmode) ) { *(.bios) }

	_i386boot_bios = LOADADDR(.bios);
	_i386boot_bios_size = SIZEOF(.bios);


  . = .;
  __u_boot_cmd_start = .;
  .u_boot_cmd : { *(.u_boot_cmd) }
  __u_boot_cmd_end = .;


	/* The load addresses below assumes that the flash
	 * will be mapped so that 0x387f0000 == 0xffff0000
	 * at reset time
	 *
	 * The fe00 and ff00 offsets of the start32 and start16
	 * segments are arbitrary, the just have to be mapped
	 * at reset and the code have to fit.
	 * The fff0 offset of reset is important, however.
	 */

	. = 0xfffffe00;
	.start32 : AT (0x3807fe00) { *(.start32); }

	. = 0xf800;
	.start16 : AT (0x3807f800) { *(.start16); }

	. = 0xfff0;
	.reset : AT (0x3807fff0) { *(.reset); }
	_i386boot_end = (LOADADDR(.reset) + SIZEOF(.reset) );
}