[ARM] Kirkwood: support L2 writeback mode

This patch allows booting Kirkwood with the L2 in writeback mode,
by reading the WT override bit from the L2 config register and
passing that into the Feroceon L2 init routine, instead of assuming
that the WT override bit will always be set

Signed-off-by: Saeed Bishara <saeed@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

2 files changed, 8 insertions, 2 deletions

diff --git a/arch/arm/mach-kirkwood/common.c b/arch/arm/mach-kirkwood/common.c
index e73384fbbba8..5938a3b33cdc 100644
--- a/arch/arm/mach-kirkwood/common.c
+++ b/arch/arm/mach-kirkwood/common.c
@@ -313,6 +313,11 @@ static char * __init kirkwood_id(void)
         return "unknown 88F6000 variant";
 }
 
+static int __init is_l2_writethrough(void)
+{
+        return !!(readl(L2_CONFIG_REG) & L2_WRITETHROUGH);
+}
+
 void __init kirkwood_init(void)
 {
         printk(KERN_INFO "Kirkwood: %s, TCLK=%d.\n",
@@ -321,6 +326,6 @@ void __init kirkwood_init(void)
         kirkwood_setup_cpu_mbus();
 
 #ifdef CONFIG_CACHE_FEROCEON_L2
-        feroceon_l2_init(1);
+        feroceon_l2_init(is_l2_writethrough());
 #endif
 }
diff --git a/include/asm-arm/arch-kirkwood/kirkwood.h b/include/asm-arm/arch-kirkwood/kirkwood.h
index 520250dbd8a3..bb31b315c350 100644
--- a/include/asm-arm/arch-kirkwood/kirkwood.h
+++ b/include/asm-arm/arch-kirkwood/kirkwood.h
@@ -49,7 +49,6 @@
 #define BRIDGE_VIRT_BASE        (KIRKWOOD_REGS_VIRT_BASE | 0x20000)
 #define  CPU_CONTROL            (BRIDGE_VIRT_BASE | 0x0104)
 #define   CPU_RESET             0x00000002
-//#define   L2_WRITETHROUGH     0x00020000
 #define  RSTOUTn_MASK           (BRIDGE_VIRT_BASE | 0x0108)
 #define   SOFT_RESET_OUT_EN     0x00000004
 #define  SYSTEM_SOFT_RESET      (BRIDGE_VIRT_BASE | 0x010c)
@@ -65,6 +64,8 @@
 #define   IRQ_CAUSE_HIGH_OFF    0x0010
 #define   IRQ_MASK_HIGH_OFF     0x0014
 #define  TIMER_VIRT_BASE        (BRIDGE_VIRT_BASE | 0x0300)
+#define  L2_CONFIG_REG          (BRIDGE_VIRT_BASE | 0x0128)
+#define   L2_WRITETHROUGH       0x00000010
 
 /*
  * Register Map