CCS/STARTERWARE-SITARA: Running bare-metal application from U-boot

ranchu

Guru 20755 points

Tool/software: Code Composer Studio

Hello,

I would like to build a standalone application which print some characters in uart , and I want to loas and run it from u-boot:

As I understand:

1. Timer (ticks) is not required for standalone application, ( Right ?)

2. I need main() function. Inside the main function I can create a loop and write into UART interface registers , something like this:

void main()

{

.............

while(1)

{

// wait until there is room in the FIFO.
while (CHKBIT_REGB(uart + UART_SSR, TX_FIFO_FULL))
;

// send the character.
OUT_REGB(uart + UART_THR, in_data);

}

3. The build with cross compile creates elf file, which I then converted to hex, and makeimage to create u-boot loadable binary.

4. I assume that the u-boot initialization still available when moving from u-boot to the standalone application.

5. We can't return from main back to u-boot as far as I understand.

Are these assumptions correct ? Should this standalone application work ?

Can I use bootelf command instead of converting elf->hex-> u-boot_hdr_img ?

Regards,

Ran

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

The software team have been notified. They will respond here.

0 Biser Gatchev-XID over 8 years ago in reply to Biser Gatchev-XID

TI__Guru**** 393215 points

By the way, have you considered using RTOS? You can find it here: software-dl.ti.com/.../index_FDS.html

0 Kemal R. Shakir over 8 years ago in reply to Biser Gatchev-XID

TI__Guru 55345 points

Hello Ran,

Please, check the <Processor SDK>/board-support/<u-boot-version>/examples/standalone/hello_world.c example. There are no timers used on it. You can load it at address 0x80300000 trough UART or TFTP as per the Standalone HOWTO guide written in main <u-boot-version>/README file.

Best regards,
Kemal

0 ranchu over 8 years ago in reply to Kemal R. Shakir

Guru 20755 points

Hello Kemal,

Thanks a lot that answered the original question for me.
Yet, I would please like to ask on this same subject:
After doing it successfully from u-boot, I then tried to load a standalone directly from MLO.
In MLO source code I first needed to edit the load address.
the standalone application I downloaded was uc/os which uses 0x80000000 as start address.
So after changing it to CFG LOAD address from 0x80008000 to 0x80000000, it boot fine.
But surprsingly I see that u-boot also still boots without issues (while expecting it to only boot with load address 0x80008000).
How can that be ?

Thank you,
Ran

0 Kemal R. Shakir over 8 years ago in reply to ranchu

TI__Guru 55345 points

Try to clean the area with mw.b 0x80000000 0xff 0x8000 command or power on/off cycle the board, since the DDR memory will keep its content until power down.

0 ranchu over 8 years ago in reply to Kemal R. Shakir

Guru 20755 points

Hello Kemal,

Your suggestions were very helpful. I hope you can assist on the following:
I try to load a standalone application build in eclipse with .ld script.
The example syntax of ld script is:
MEMORY { .Code : ORIGIN = 0x80100000, LENGTH = (30*1024*1024)}
MEMORY { .InitData : ORIGIN = 0x81F00000, LENGTH = (4 * 1024*1024)}
MEMORY { .NonInitData : ORIGIN = 0x82300000, LENGTH = (29 * 1024*1024)}
MEMORY { .ConfigFiles : ORIGIN = 0x84000000, LENGTH = (4 * 1024*1024)}
MEMORY { .HeapData : ORIGIN = 0x84400000, LENGTH = (32 * 1024*1024)}
MEMORY { .DMAData : ORIGIN = 0x86400000, LENGTH = (1024 * 1024)}
MEMORY { .TTBData : ORIGIN = 0x86500000, LENGTH = (32 * 1024)}

But The bin file is now very big 30M, how can I make the script create a bin file in required size (not bigger than the real code), just as done in the hello_world example (the hello_world example only get start address, not length)

I tried to change from:

MEMORY { .Code : ORIGIN = 0x80100000, LENGTH = (30*1024*1024)}

MEMORY { .Code : ORIGIN = 0x80100000, LENGTH = (1*1024*1024)}

But It didn't help.

load script attached.

As alternative - if .bin file is too big is there a way to load standalone application into u-boot/MLO in other format ?

Thank you,
Ran

Fullscreen ld.txt Download

MEMORY { .Code          : ORIGIN = 0x80100000, LENGTH = (30 * 1024*1024)}  
MEMORY { .InitData      : ORIGIN = 0x81F00000, LENGTH = (4  * 1024*1024)}  
MEMORY { .NonInitData   : ORIGIN = 0x82300000, LENGTH = (29 * 1024*1024)}  
MEMORY { .ConfigFiles   : ORIGIN = 0x84000000, LENGTH = (4  * 1024*1024)}  
MEMORY { .HeapData      : ORIGIN = 0x84400000, LENGTH = (32 * 1024*1024)}  
MEMORY { .DMAData       : ORIGIN = 0x86400000, LENGTH = (1024 * 1024)}
MEMORY { .TTBData       : ORIGIN = 0x86500000, LENGTH = (32 * 1024)}
OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
OUTPUT_ARCH(arm)

ENTRY(_start)

SECTIONS
{
	. = 0x00000000;
	. = ALIGN(4);
	
	.text :
	{
	__image_copy_start = .;
	S:\HBS\out\start.o (.text)
	*(.text .text.* .gnu.linkonce.t.*)
	}>.Code

	.Config :
	{
	  PROVIDE_HIDDEN (__config_start = .);
	  . = . + 4194304;
	  PROVIDE_HIDDEN (__config_end = .);
	}>.ConfigFiles

	.heap :
	{
	  . = ALIGN(16);
	  PROVIDE_HIDDEN (__heap_start = .);
	  . = . + 16777216;
	  PROVIDE_HIDDEN (__heap_end = .);
	}>.HeapData

	.ttb :
	{
	  . = ALIGN(16384);
	  PROVIDE_HIDDEN (__ttb_start = .);
	  . = . + 16384;
	  PROVIDE_HIDDEN (__ttb_end = .);
	}>.TTBData

	.dma :
	{
	  . = ALIGN(16);
	  PROVIDE_HIDDEN (__dma_start = .);
/*	  . = . + 1048576; */
	  PROVIDE_HIDDEN (__dma_end = .);
	}>.DMAData

	.init_array :
	{
	PROVIDE_HIDDEN (__init_array_start = .);
    KEEP (*(SORT(.init_array.*)))
    KEEP (*(.init_array*))
    PROVIDE_HIDDEN (__init_array_end = .);
	}>.InitData

	.fini_array :
	{
	  PROVIDE_HIDDEN (__fini_array_start = .);
      KEEP (*(SORT(.init_array.*)))
      KEEP (*(.fini_array*))
      PROVIDE_HIDDEN (__fini_array_end = .);
	}>.InitData

	. = ALIGN(4);
	
	.rodata : 
	{ 
	*(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*))) 
	} >.Code
	
	. = ALIGN(4);
	
	.data : 
	{
	*(.data)
	} >.InitData
	
	. = ALIGN(4);
	. = .;
		
	.dynsym : 
	{
	__dynsym_start = .;
	*(.dynsym)
	}
	_end = .;
	. = ALIGN(4096);
	
	.bss : 
	{
	__bss_start = .;
	*(.bss)
	. = ALIGN(4);
	__bss_end__ = .;
	}> .NonInitData
	
}

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CCS/STARTERWARE-SITARA: Running bare-metal application from U-boot