Minimal MMU linux hangs on DE1 board

Don't know if it is insufficient memory. It hangs but what error reports do you get?

1.- I store in flash both OS Image and filesystem

2.- See whole thread

3.- modified DE2

4.- The wiki (carefully)

Hello, i am having similar problem.

I've done everything Hippio said (Edit the RC file and the blackfin option), however my linux hangs after:

Linux version 2.6.34-00692-g5bc7853-dirty ([email protected]) (gcc version 4.1.2)# 37 Mon Nov 1 15:54:39 BRST 2010
bootconsole  enabled
early_console initialized at 0xe1801440
Linux/Nios II-MMU
init_bootmem_node(?,0xce6, 0x800, 0x1000)
free_bootmem(0xce6000, 0x31a000)
reserve_bootmem(0xce6000, 0x100)

(Before i saw this thread it was hangin on the first paragraph)

I am using a DE2 , my design has a NIOS(f), onchipmemory, 8 MB SDRAM, JTAG UART, EPCS and a flash. Really simple.

Any suggestions?

Hi ,

We are also using the same method to bring up DE1 board with bare minimum MMU support on the uClinux.

And tried compiling uclinux by taking a refrence board 3c120 and it gets compiled properly with our own mmu project. When i load the image on the board it gets hangs giving below error

Uncompressing Linux...

ERROR

bad gzip magic numbers

Please provide a solution to move further

Thanks and regards

Tejeshwar

Now i am done with uncompressing. But before booting the kernel after uncompressing system hangs while flushing the data cache. Below is the assembly code being used to flush dcache.

movia r1, NIOS2_DCACHE_SIZE

movui r2, NIOS2_DCACHE_LINE_SIZE

1: flushd 0(r1)

sub r1, r1, r2

call debug_print

bgt r1, r0, 1b

NIOS2_DCACHE_SIZE = 2k

NIOS2_DCACHE_LINE_SIZE = 32

I am not able to figure out . Please help.

Thanks

Tejeshwar

Not sure you want a print call in that loop!

I'd expect r2 to have the value 32 (line size)

r0 initialised to some cache address.

r1 initialised to r2 + cache size.

That print debug_print i have put it for debug purpose.

This is the code which executes before starting the linux

/*

* linux/arch/nios2/boot/compressed/head.S

*

* This code can be loaded anywhere, eg FLASH ROM as reset vector,

* as long as output does not overlap it.

*/

# include <asm/asm-offsets.h>

# include <asm/asm-macros.h>

.text

.set noat

.global _start

_start:

wrctl status, r0 /* disable interrupt */

/* invalidate all instruction cache */

movia r1, NIOS2_ICACHE_SIZE

movui r2, NIOS2_ICACHE_LINE_SIZE

1: initi r1

sub r1, r1, r2

bgt r1, r0, 1b

/* invalidate all data cache */

movia r1, NIOS2_DCACHE_SIZE

movui r2, NIOS2_DCACHE_LINE_SIZE

1: initd 0(r1)

sub r1, r1, r2

bgt r1, r0, 1b

nextpc r1 /* Find out where we are */

chkadr:

movia r2, chkadr

beq r1, r2, finish_move /* We are running in correct address, done */

/* move code, r1: src, r2: dest, r3: last dest */

addi r1, r1, (_start - chkadr) /* Source */

movia r2, _start /* Destination */

movia r3, __bss_start /* End of copy */

1: ldw r8, 0(r1) /* load a word from [r1] */

stw r8, 0(r2) /* stort a word to dest [r2] */

addi r1, r1, 4 /* inc the src addr */

addi r2, r2, 4 /* inc the dest addr */

blt r2, r3, 1b

/* flush the data cache after moving */

movia r1, NIOS2_DCACHE_SIZE

movui r2, NIOS2_DCACHE_LINE_SIZE

1: flushd 0(r1)

sub r1, r1, r2

call debug_print

bgt r1, r0, 1b

movia r1, finish_move

jmp r1 /* jmp to linked address */

finish_move:

/* zero out the .bss segment (uninitialized common data) */

movia r2, __bss_start /* presume nothing is between */

movia r1, _end /* the .bss and _end. */

1: stb r0, 0(r2)

addi r2, r2, 1

bne r1, r2, 1b

/*

* set up the stack pointer, some where higher than _end.

* The stack space must be greater than 32K for decompress.

*/

movia sp, 0x10000

add sp, sp, r2

/* save args passed from u-boot, maybe */

addi sp, sp, -16

stw r4, 0(sp)

stw r5, 4(sp)

stw r6, 8(sp)

stw r7, 12(sp)

/* decompress the kernel */

call decompress_kernel

/* pass saved args to kernel */

ldw r4, 0(sp)

ldw r5, 4(sp)

ldw r6, 8(sp)

ldw r7, 12(sp)

/* flush all data cache after decompressing */

movia r1, NIOS2_DCACHE_SIZE

movui r2, NIOS2_DCACHE_LINE_SIZE

1: flushd 0(r1)

sub r1, r1, r2

call debug_print

bgt r1, r0, 1b

/* flush all instruction cache */

movia r1, NIOS2_ICACHE_SIZE

movui r2, NIOS2_ICACHE_LINE_SIZE

1: flushi r1

sub r1, r1, r2

bgt r1, r0, 1b

flushp

/* jump to start real kernel */

movia r1, (LINUX_SDRAM_START | KERNEL_REGION_BASE_ASM)

call debug_print

jmp r1

data cache flush is happening in the subroutine chkadr and there its working fine , but in the subroutine finish_move the same thing flushing of data cache is going in an infinite loop.

Pls help me out what could be the issue.

Now uncompress is happening . but linux is not booting . What could be the issue ??

On the console i see ..

Uncompressing Linux... Ok, booting the kernel.

It stops here. Please help me how to debug or what can the issue

Thanks and regards

Tejeshwar

--- Quote Start ---

Not sure you want a print call in that loop!

I'd expect r2 to have the value 32 (line size)

r0 initialised to some cache address.

r1 initialised to r2 + cache size.

--- Quote End ---

Hi ,

I am following the steps for compiling the linux as explained in the below address,

http://www.alterawiki.com/wiki/uclinuxdist

But the uclinux hangs after uncompressing , on the console i get

Uncompressing linux ... Ok booting kernel ,

and stops here.

I have attached sopcinfo, ptf and sof file .

Can u help me is there any problem in the design.

Regards,

Tejeshwar K