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ARM9 Boot- Booting AT91SAM9263 from NOR-Flash

Daniel Bojara

Hi,
i use a AT91SAM9263 and i will boot it from nor-flash. At boot time i must switch the master clock at a higher frequency. This switch can’t be performed from NOR flash, as the access timings to
the chip are different with the two clocks.

The solution in ATMEL Bootstrap v1.9 (crt0_gnu.s) is:

...
undef_vector:
        b       undef_vector
swi_vector:
        b       swi_vector
pabt_vector:
        b       pabt_vector
dabt_vector:
        b       dabt_vector
rsvd_vector:
        b       rsvd_vector
irq_vector:
        b       irq_vector
fiq_vector:
        b       fiq_vector
reset_vector:

/* Init the stack */
_init_stack:
        ldr     sp,=TOP_OF_MEM

#ifdef CFG_NORFLASH
/*
 * When running from NOR, we must relocate to SRAM prior to resetting
 * the clocks and SMC timings.
 */
_relocate_to_sram:

#if 0
        /* relocation is slow, disable the watchdog or it will trigger */
        ldr     r1, =0xFFFFFD44
        mov     r2, #0x00008000
        str     r2, [r1]
#endif

        mov     r1, #0
        ldr     r3, =_stext
        ldr     r4, =_edata
1:
        cmp     r3, r4
        ldrcc   r2, [r1], #4
        strcc   r2, [r3], #4
        bcc     1b
        ldr     pc, =_setup_clocks
#endif /* CFG_NORFLASH */

_setup_clocks:
/* Test if main oscillator is enabled */
        ldr     r0,=AT91C_PMC_SR
        ldr     r1, [r0]
        ldr     r2,=AT91C_PMC_MOSCS
        ands    r1, r1, r2
        bne     _switch_to_mosc
....

The important part is:

        mov     r1, #0
        ldr     r3, =_stext
        ldr     r4, =_edata

1:
        cmp     r3, r4
        ldrcc   r2, [r1], #4
        strcc   r2, [r3], #4
        bcc     1b
        ldr     pc, =_setup_clocks


I convert this in my startup-file:

....

; Reset Handler

                EXPORT  Reset_Handler
Reset_Handler

;/*
; * When running from NOR, we must relocate to SRAM prior to resetting
; * the clocks and SMC timings.
; */

        mov     r1, #0
        ldr     r3, =0x00300000 ;SRAM
        ldr     r4, =||Image$$ER_IROM1$$RO$$Length||+||Image$$RW_IRAM1$$RW$$Length||

copy
        ldrcc   r2, [r1, #4]! ; R2 = Wert von Adresse R1+4, R1 wird um 4 erhöht
        strcc   r2, [r3, #4]! ; speichere R3+Offset in R2
        cmp             r3, r4
        bne             copy

        ldr             pc, =_init_pmc

; Setup Power Management Controller (PMC) --------------------------------------

_init_pmc
                IF      :DEF:NO_PMC_INIT
                ELSE
                IF      PMC_SETUP != 0
....

but these don't work!

0