ARM: Improve the L2 cache performance when PL310 is used

With this L2 cache controller, the cache maintenance by PA and sync
operations are atomic and do not require a "wait" loop. This patch
conditionally defines the cache_wait() function.

Since L2x0 cache controllers do not work with ARMv7 CPUs, the patch
automatically enables CACHE_PL310 when only CPU_V7 is defined.

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

2 files changed, 20 insertions, 3 deletions

diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index a0a2928ae4dd..4414a01e1e8a 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -779,6 +779,14 @@ config CACHE_L2X0
         help
           This option enables the L2x0 PrimeCell.
 
+config CACHE_PL310
+        bool
+        depends on CACHE_L2X0
+        default y if CPU_V7 && !CPU_V6
+        help
+          This option enables optimisations for the PL310 cache
+          controller.
+
 config CACHE_TAUROS2
         bool "Enable the Tauros2 L2 cache controller"
         depends on (ARCH_DOVE || ARCH_MMP)
diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index 9982eb385c0f..edb43ff7aeef 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -29,13 +29,22 @@ static void __iomem *l2x0_base;
 static DEFINE_SPINLOCK(l2x0_lock);
 static uint32_t l2x0_way_mask;  /* Bitmask of active ways */
 
-static inline void cache_wait(void __iomem *reg, unsigned long mask)
+static inline void cache_wait_way(void __iomem *reg, unsigned long mask)
 {
-        /* wait for the operation to complete */
+        /* wait for cache operation by line or way to complete */
         while (readl_relaxed(reg) & mask)
                 ;
 }
 
+#ifdef CONFIG_CACHE_PL310
+static inline void cache_wait(void __iomem *reg, unsigned long mask)
+{
+        /* cache operations by line are atomic on PL310 */
+}
+#else
+#define cache_wait      cache_wait_way
+#endif
+
 static inline void cache_sync(void)
 {
         void __iomem *base = l2x0_base;
@@ -110,7 +119,7 @@ static inline void l2x0_inv_all(void)
         /* invalidate all ways */
         spin_lock_irqsave(&l2x0_lock, flags);
         writel_relaxed(l2x0_way_mask, l2x0_base + L2X0_INV_WAY);
-        cache_wait(l2x0_base + L2X0_INV_WAY, l2x0_way_mask);
+        cache_wait_way(l2x0_base + L2X0_INV_WAY, l2x0_way_mask);
         cache_sync();
         spin_unlock_irqrestore(&l2x0_lock, flags);
 }