Check whether the SCU was already initialised

If Linux is running in non-secure mode, this register may have been
already initialised and writing to the control register not allowed.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
index d3831f616ee9f334bdfc0bf453512348597bea35..9ab4149bd9830883f88d2b1d20739c981a344551 100644 (file)
--- a/arch/arm/kernel/smp_scu.c
+++ b/arch/arm/kernel/smp_scu.c
@@ -37,6 +37,10 @@ void __init scu_enable(void __iomem *scu_base)
        u32 scu_ctrl;
 
        scu_ctrl = __raw_readl(scu_base + SCU_CTRL);
+       /* already enabled? */
+       if (scu_ctrl & 1)
+               return;
+
        scu_ctrl |= 1;
        __raw_writel(scu_ctrl, scu_base + SCU_CTRL);