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+/*
+ * relocate - i.MX27-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.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)