[ARM] 4500/1: Add locking around the background L2x0 cache operations

The background operations of the L2x0 cache controllers are aborted if
another operation is issued on the same or different core. This patch
protects the maintenance operation issuing/polling with a spinlock.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index 08a36f1b35d2..b4e9b734e0bd 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -17,6 +17,7 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 #include <linux/init.h>
+#include <linux/spinlock.h>
 
 #include <asm/cacheflush.h>
 #include <asm/io.h>
@@ -25,14 +26,19 @@
 #define CACHE_LINE_SIZE         32
 
 static void __iomem *l2x0_base;
+static DEFINE_SPINLOCK(l2x0_lock);
 
 static inline void sync_writel(unsigned long val, unsigned long reg,
                                unsigned long complete_mask)
 {
+        unsigned long flags;
+
+        spin_lock_irqsave(&l2x0_lock, flags);
         writel(val, l2x0_base + reg);
         /* wait for the operation to complete */
         while (readl(l2x0_base + reg) & complete_mask)
                 ;
+        spin_unlock_irqrestore(&l2x0_lock, flags);
 }
 
 static inline void cache_sync(void)