[PATCH 22/75] ARM: l2c: only write the auxiliary control register if required

Russell King rmk+kernel at arm.linux.org.uk
Fri Mar 28 11:16:12 EDT 2014


Avoid unnecessary writes to the auxiliary control register if the
register already contains the required value.  This allows us to
avoid invoking the platforms secure monitor code unnecessarily.

Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
---
 arch/arm/mm/cache-l2x0.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index fc609550b7fa..1c947b4c7f05 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -92,7 +92,9 @@ static void l2c_enable(void __iomem *base, u32 aux, unsigned num_lock)
 {
 	unsigned long flags;
 
-	writel_relaxed(aux, base + L2X0_AUX_CTRL);
+	/* Only write the aux register if it needs changing */
+	if (readl_relaxed(base + L2X0_AUX_CTRL) != aux)
+		writel_relaxed(aux, base + L2X0_AUX_CTRL);
 
 	l2c_unlock(base, num_lock);
 
-- 
1.8.3.1




More information about the linux-arm-kernel mailing list