view target-utils/tf-breakin/payload.S @ 764:26daa2720bda

doc/DUART28-boot-control: update on the Linux driver patch status
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 06 Dec 2020 04:07:48 +0000
parents e7502631a0f9
children
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	.text
	.org	0

@ allow entry in Thumb state
	.code	16
	bx	pc
	nop

	.code	32

@ set CPSR like mot931c payload does
	msr	CPSR_c, #0xd3
@ disable the watchdog
	ldr	r1, =0xfffff802
	mov	r0, #0xf5
	strh	r0, [r1, #2]
	mov	r0, #0xa0
	strh	r0, [r1, #2]
@ MODEM UART
	ldr	r6, =0xffff5800
@ wait for any previous output to flush out
1:	ldrb	r0, [r6, #5]
	tst	r0, #0x20
	beq	1b
@ send our indication
	adr	r1, outstr
	mov	r2, #6
1:	ldrb	r0, [r1], #1
	strb	r0, [r6]
	subs	r2, r2, #1
	bne	1b
@ wait for this output to go out to the TxD pin
1:	ldrb	r0, [r6, #5]
	tst	r0, #0x40
	beq	1b
@ enable the Calypso boot ROM
	ldr	r1, =0xFFFFFB10
	mov	r2, #0x0100
	strh	r2, [r1]
@ jump to it!
	mov	pc, #0
	.ltorg
outstr:	.byte	2,2,2,'O','K',2