ARM: 7846/1: Update SMP_ON_UP code to detect A9MPCore with 1 CPU devices

[karo-tx-linux.git] / arch / arm / kernel / head.S

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 2c7cc1e03473aee9463e86d7dbedfc999f6e51f7..476de57dcef284602e126e29e2da03465df8ff09 100644 (file)
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -487,7 +487,26 @@ __fixup_smp:
        mrc     p15, 0, r0, c0, c0, 5   @ read MPIDR
        and     r0, r0, #0xc0000000     @ multiprocessing extensions and
        teq     r0, #0x80000000         @ not part of a uniprocessor system?
-       moveq   pc, lr                  @ yes, assume SMP
+       bne    __fixup_smp_on_up        @ no, assume UP
+
+       @ Core indicates it is SMP. Check for Aegis SOC where a single
+       @ Cortex-A9 CPU is present but SMP operations fault.
+       mov     r4, #0x41000000
+       orr     r4, r4, #0x0000c000
+       orr     r4, r4, #0x00000090
+       teq     r3, r4                  @ Check for ARM Cortex-A9
+       movne   pc, lr                  @ Not ARM Cortex-A9,
+
+       @ If a future SoC *does* use 0x0 as the PERIPH_BASE, then the
+       @ below address check will need to be #ifdef'd or equivalent
+       @ for the Aegis platform.
+       mrc     p15, 4, r0, c15, c0     @ get SCU base address
+       teq     r0, #0x0                @ '0' on actual UP A9 hardware
+       beq     __fixup_smp_on_up       @ So its an A9 UP
+       ldr     r0, [r0, #4]            @ read SCU Config
+       and     r0, r0, #0x3            @ number of CPUs
+       teq     r0, #0x0                @ is 1?
+       movne   pc, lr
 
 __fixup_smp_on_up:
        adr     r0, 1f