ARM: exynos: Fix imprecise abort during Exynos5422 suspend to RAM

Suspend to RAM on Odroid XU3/XU4/HC1 family (Exynos5422) causes
imprecise abort:

	PM: Syncing filesystems ... done.
	Freezing user space processes ... (elapsed 0.003 seconds) done.
	OOM killer disabled.
	Freezing remaining freezable tasks ... (elapsed 0.003 seconds) done.
	wake enabled for irq 139
	Disabling non-boot CPUs ...
	IRQ51 no longer affine to CPU1
	IRQ52 no longer affine to CPU2
	IRQ53 no longer affine to CPU3
	IRQ54 no longer affine to CPU4
	IRQ55 no longer affine to CPU5
	IRQ56 no longer affine to CPU6
	cpu cpu4: Dropping the link to regulator.40
	IRQ57 no longer affine to CPU7
	Unhandled fault: external abort on non-linefetch (0x1008) at 0xf081a028
	Internal error: : 1008 [#1] PREEMPT SMP ARM

with last call trace in exynos_suspend_enter().

The abort is caused by writing to register in secure part of sysram.
Boards booted under secure firmware (e.g. Hardkernel Odroid boards)
should access non-secure sysram.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

1 files changed, 11 insertions, 3 deletions

diff --git a/arch/arm/mach-exynos/firmware.c b/arch/arm/mach-exynos/firmware.c
index be1f20fe28f4..d602e3bf3f96 100644
--- a/arch/arm/mach-exynos/firmware.c
+++ b/arch/arm/mach-exynos/firmware.c
@@ -185,7 +185,7 @@ static void exynos_l2_configure(const struct l2x0_regs *regs)
 	exynos_smc(SMC_CMD_L2X0SETUP2, regs->pwr_ctrl, regs->aux_ctrl, 0);
 }
 
-void __init exynos_firmware_init(void)
+bool __init exynos_secure_firmware_available(void)
 {
 	struct device_node *nd;
 	const __be32 *addr;
@@ -193,14 +193,22 @@ void __init exynos_firmware_init(void)
 	nd = of_find_compatible_node(NULL, NULL,
 					"samsung,secure-firmware");
 	if (!nd)
-		return;
+		return false;
 
 	addr = of_get_address(nd, 0, NULL, NULL);
 	if (!addr) {
 		pr_err("%s: No address specified.\n", __func__);
-		return;
+		return false;
 	}
 
+	return true;
+}
+
+void __init exynos_firmware_init(void)
+{
+	if (!exynos_secure_firmware_available())
+		return;
+
 	pr_info("Running under secure firmware.\n");
 
 	register_firmware_ops(&exynos_firmware_ops);