From: Fabio Estevam fabio.estevam@freescale.com
Since commit ("arm: relocate the exception vectors") mx25pdk hangs like this:
CPU: Freescale i.MX25 rev1.2 at 399 MHz Reset cause: WDOG Board: MX25PDK I2C: ready DRAM: 64 MiB (hangs)
We need to add a specific relocate_vectors macro, just like it was done for mx27 SoC in commit db544b9662622826b8 ("imx: fix exception vectors relocation in imx27").
This allows mx25 to boot again.
Signed-off-by: Fabio Estevam fabio.estevam@freescale.com --- arch/arm/cpu/arm926ejs/mx25/Makefile | 4 +++ arch/arm/cpu/arm926ejs/mx25/relocate.S | 51 ++++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+) create mode 100644 arch/arm/cpu/arm926ejs/mx25/relocate.S
diff --git a/arch/arm/cpu/arm926ejs/mx25/Makefile b/arch/arm/cpu/arm926ejs/mx25/Makefile index 134c69d..ebc0407 100644 --- a/arch/arm/cpu/arm926ejs/mx25/Makefile +++ b/arch/arm/cpu/arm926ejs/mx25/Makefile @@ -5,3 +5,7 @@ # SPDX-License-Identifier: GPL-2.0+
obj-y = generic.o timer.o reset.o + +ifndef CONFIG_SPL_BUILD +obj-y += relocate.o +endif diff --git a/arch/arm/cpu/arm926ejs/mx25/relocate.S b/arch/arm/cpu/arm926ejs/mx25/relocate.S new file mode 100644 index 0000000..e0dfdee --- /dev/null +++ b/arch/arm/cpu/arm926ejs/mx25/relocate.S @@ -0,0 +1,51 @@ +/* + * relocate - i.MX25-specific vector relocation + * + * Copyright (c) 2013 Albert ARIBAUD albert.u.boot@aribaud.net + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <asm-offsets.h> +#include <config.h> +#include <linux/linkage.h> + +/* + * The i.MX25 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.MX25, 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.MX25 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)