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u-boot/arch/arm/cpu/arm926ejs/mx27/relocate.S

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SPDX: Convert all of our single license tags to Linux Kernel style When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-06 21:58:06 +00:00
/* SPDX-License-Identifier: GPL-2.0+ */
imx: fix exception vectors relocation in imx27 Commit 3ff46cc4 fixed exception vectors setting in the general ARM case, by either copying the exception and indirect vector tables to normal (0x00000000) or high (0xFFFF0000) vectors address, or setting VBAR to U-Boot's base if applicable. i.MX27 SoC is ARM926E-JS, thus has only normal and high options, but does not provide RAM at 0xFFFF0000 and has only ROM at 0x00000000; it is therefore not possible to move or change its exception vectors. Besides, i.MX27 ROM code does provide an indirect vectors table but at a non-standard address and with the reset and reserved vectors missing. Turn the current vector relocation code into a weak routine called after relocate_code from crt0, and add strong version for i.MX27. Series-Cc: Heiko Schocher <hs@denx.de> Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net> Reviewed-by: Stefano Babic <sbabic@denx.de> Tested-by: Stefano Babic <sbabic@denx.de> Tested-by: Philippe Reynes <tremyfr@gmail.com> Tested-by: Philippe Reynes <tremyfr@yahoo.fr>
2014-11-13 16:59:15 +00:00
/*
* relocate - i.MX27-specific vector relocation
*
* Copyright (c) 2013 Albert ARIBAUD <albert.u.boot@aribaud.net>
*/
#include <asm-offsets.h>
#include <config.h>
#include <linux/linkage.h>
/*
* The i.MX27 SoC is very specific with respect to exceptions: it
* does not provide RAM at the high vectors address (0xFFFF0000),
* thus only the low address (0x00000000) is useable; but that is
* in ROM. Therefore, vectors cannot be changed at all.
*
* However, these ROM-based vectors actually just perform indirect
* calls through pointers located in RAM at SoC-specific addresses,
* as follows:
*
* Offset Exception Use by ROM code
* 0x00000000 reset indirect branch to [0x00000014]
* 0x00000004 undefined instruction indirect branch to [0xfffffef0]
* 0x00000008 software interrupt indirect branch to [0xfffffef4]
* 0x0000000c prefetch abort indirect branch to [0xfffffef8]
* 0x00000010 data abort indirect branch to [0xfffffefc]
* 0x00000014 (reserved in ARMv5) vector to ROM reset: 0xc0000000
* 0x00000018 IRQ indirect branch to [0xffffff00]
* 0x0000001c FIQ indirect branch to [0xffffff04]
*
* In order to initialize exceptions on i.MX27, we must copy U-Boot's
* indirect (not exception!) vector table into 0xfffffef0..0xffffff04
* taking care not to copy vectors number 5 (reserved exception).
*/
.section .text.relocate_vectors,"ax",%progbits
ENTRY(relocate_vectors)
ldr r0, [r9, #GD_RELOCADDR] /* r0 = gd->relocaddr */
ldr r1, =32 /* size of vector table */
add r0, r0, r1 /* skip to indirect table */
ldr r1, =0xFFFFFEF0 /* i.MX27 indirect table */
ldmia r0!, {r2-r8} /* load indirect vectors 1..7 */
stmia r1!, {r2-r5, r7,r8} /* write all but vector 5 */
bx lr
ENDPROC(relocate_vectors)
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