diff options
Diffstat (limited to 'arch/arm/cpu/arm926ejs/mxs/mxs.c')
| -rw-r--r-- | arch/arm/cpu/arm926ejs/mxs/mxs.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/arch/arm/cpu/arm926ejs/mxs/mxs.c b/arch/arm/cpu/arm926ejs/mxs/mxs.c index a5e388b..45667bd 100644 --- a/arch/arm/cpu/arm926ejs/mxs/mxs.c +++ b/arch/arm/cpu/arm926ejs/mxs/mxs.c @@ -76,13 +76,32 @@ void enable_caches(void) #endif } +/* + * This function will craft a jumptable at 0x0 which will redirect interrupt + * vectoring to proper location of U-Boot in RAM. + * + * The structure of the jumptable will be as follows: + * ldr pc, [pc, #0x18] ..... for each vector, thus repeated 8 times + * <destination address> ... for each previous ldr, thus also repeated 8 times + * + * The "ldr pc, [pc, #0x18]" instruction above loads address from memory at + * offset 0x18 from current value of PC register. Note that PC is already + * incremented by 4 when computing the offset, so the effective offset is + * actually 0x20, this the associated <destination address>. Loading the PC + * register with an address performs a jump to that address. + */ void mx28_fixup_vt(uint32_t start_addr) { - uint32_t *vt = (uint32_t *)0x20; + /* ldr pc, [pc, #0x18] */ + const uint32_t ldr_pc = 0xe59ff018; + /* Jumptable location is 0x0 */ + uint32_t *vt = (uint32_t *)0x0; int i; - for (i = 0; i < 8; i++) - vt[i] = start_addr + (4 * i); + for (i = 0; i < 8; i++) { + vt[i] = ldr_pc; + vt[i + 8] = start_addr + (4 * i); + } } #ifdef CONFIG_ARCH_MISC_INIT |