ARM: 7080/1: l2x0: make sure I&D are not locked down on init

Fighting unfixed U-Boots and other beasts that may the cache in
a locked-down state when starting the kernel, we make sure to
disable all cache lock-down when initializing the l2x0 so we
are in a known state.

Cc: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Cc: Rabin Vincent <rabin.vincent@stericsson.com>
Cc: Adrian Bunk <adrian.bunk@movial.com>
Cc: Rob Herring <robherring2@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reported-by: Jan Rinze <janrinze@gmail.com>
Tested-by: Robert Marklund <robert.marklund@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 28 insertions, 2 deletions

diff --git a/arch/arm/include/asm/hardware/cache-l2x0.h b/arch/arm/include/asm/hardware/cache-l2x0.h
index bfa706ffd968..99a6ed7e1bfd 100644
--- a/arch/arm/include/asm/hardware/cache-l2x0.h
+++ b/arch/arm/include/asm/hardware/cache-l2x0.h
@@ -45,8 +45,13 @@
 #define L2X0_CLEAN_INV_LINE_PA          0x7F0
 #define L2X0_CLEAN_INV_LINE_IDX         0x7F8
 #define L2X0_CLEAN_INV_WAY              0x7FC
-#define L2X0_LOCKDOWN_WAY_D             0x900
-#define L2X0_LOCKDOWN_WAY_I             0x904
+/*
+ * The lockdown registers repeat 8 times for L310, the L210 has only one
+ * D and one I lockdown register at 0x0900 and 0x0904.
+ */
+#define L2X0_LOCKDOWN_WAY_D_BASE        0x900
+#define L2X0_LOCKDOWN_WAY_I_BASE        0x904
+#define L2X0_LOCKDOWN_STRIDE            0x08
 #define L2X0_TEST_OPERATION             0xF00
 #define L2X0_LINE_DATA                  0xF10
 #define L2X0_LINE_TAG                   0xF30
diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index 44c086710d2b..9ecfdb511951 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -277,6 +277,25 @@ static void l2x0_disable(void)
         spin_unlock_irqrestore(&l2x0_lock, flags);
 }
 
+static void __init l2x0_unlock(__u32 cache_id)
+{
+        int lockregs;
+        int i;
+
+        if (cache_id == L2X0_CACHE_ID_PART_L310)
+                lockregs = 8;
+        else
+                /* L210 and unknown types */
+                lockregs = 1;
+
+        for (i = 0; i < lockregs; i++) {
+                writel_relaxed(0x0, l2x0_base + L2X0_LOCKDOWN_WAY_D_BASE +
+                               i * L2X0_LOCKDOWN_STRIDE);
+                writel_relaxed(0x0, l2x0_base + L2X0_LOCKDOWN_WAY_I_BASE +
+                               i * L2X0_LOCKDOWN_STRIDE);
+        }
+}
+
 void __init l2x0_init(void __iomem *base, __u32 aux_val, __u32 aux_mask)
 {
         __u32 aux;
@@ -328,6 +347,8 @@ void __init l2x0_init(void __iomem *base, __u32 aux_val, __u32 aux_mask)
          * accessing the below registers will fault.
          */
         if (!(readl_relaxed(l2x0_base + L2X0_CTRL) & 1)) {
+                /* Make sure that I&D is not locked down when starting */
+                l2x0_unlock(cache_id);
 
                 /* l2x0 controller is disabled */
                 writel_relaxed(aux, l2x0_base + L2X0_AUX_CTRL);