ARM: 8032/1: bL_switcher: fix validation check before its activation

The switcher should not depend on MAX_CLUSTER to determine ifit should
be activated or not. In a multiplatform kernel binary it is possible to
have dual-cluster and quad-cluster platforms configured in. In that case
MAX_CLUSTER which is a build time limit should be 4 and that shouldn't
prevent the switcher from working if the kernel is booted on a b.L
dual-cluster system.

In bL_switcher_halve_cpus() we already have a runtime validation check
to make sure we're dealing with only two clusters, so booting on a quad
cluster system will be caught and switcher activation aborted.

However, the b.L switcher must ensure the MCPM layer is initialized on
the booted hardware before doing anything.  The mcpm_is_available()
function is added to that effect.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Abhilash Kesavan <kesavan.abhilash@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 2 insertions, 4 deletions

diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index 5774b6ea7ad5..f01c0ee0c87e 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -797,10 +797,8 @@ static int __init bL_switcher_init(void)
 {
 	int ret;
 
-	if (MAX_NR_CLUSTERS != 2) {
-		pr_err("%s: only dual cluster systems are supported\n", __func__);
-		return -EINVAL;
-	}
+	if (!mcpm_is_available())
+		return -ENODEV;
 
 	cpu_notifier(bL_switcher_hotplug_callback, 0);