view target-utils/compalstage/compalstage.S @ 416:30f6d1c32c6f

doc/Flash-boot-defect article removed (no longer relevant) This article is no longer relevant because the issue in question only affected one (1) defective FCDEV3B board which was not and never will be sold.
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 26 Oct 2018 07:11:08 +0000
parents 21eec7569eb8
children
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	.text
	.org	0

#if THUMB_ENTRY
	.code	16
	bx	pc
	nop
#endif
	.code	32

/* delay loop like OsmocomBB does */
	mov	r1, #0xa0000
1:	subs	r1, r1, #1
	bne	1b
/* enable the Calypso boot ROM */
	ldr	r1, reg_addr
	mov	r2, #0x0100
	strh	r2, [r1]
/* jump to it! */
	mov	pc, #0
reg_addr:
	.word	0xFFFFFB10

#if PAD_TO_1003
/*
 * The older and most familiar versions of C139/140 boot code expect the
 * signature bytes to be "1003" or greater, but a recently encountered
 * newer version expects them to be "1004" or greater instead.  As the
 * actual comparison check in all currently known boot code versions is
 * an inequality (the signature bytes in the downloaded image need to be
 * greater than or equal to the hard-coded reference values), always
 * putting "1004" in our compalstage image instead of "1003" should satisfy
 * all existing C1xx boot code versions, or at least all currently known
 * ones.  However, having an image named compalstage-1003.bin with the
 * corresponding -c 1003 loadtools option that is actually "1004" inside
 * feels a little "wrong" in some sense, while getting rid of the -c 1003
 * option would break old user instructions, hence let's go ahead and do the
 * silly exercise of building both "1003" and "1004" versions.
 */
	.org	0x3be0
#if MAGIC_1004
	.ascii	"1004"
#else
	.ascii	"1003"
#endif
#endif