[PATCH v2] ARM: l2x0: make sure I&D are not locked down on init

[Linus Walleij]

From: Linus Walleij <linus.walleij at linaro.org>

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 at stericsson.com>
Cc: Rabin Vincent <rabin.vincent at stericsson.com>
Cc: Adrian Bunk <adrian.bunk at movial.com>
Cc: Rob Herring <robherring2 at gmail.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will.deacon at arm.com>
Reported-by: Jan Rinze <janrinze at gmail.com>
Tested-by: Robert Marklund <robert.marklund at stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
 arch/arm/include/asm/hardware/cache-l2x0.h |    9 +++++++--
 arch/arm/mm/cache-l2x0.c                   |   21 +++++++++++++++++++++
 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 16bd480..9e2fd18 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 44c0867..9ecfdb5 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);
-- 
1.7.3.2