ARM: MM: Add DT binding for Feroceon L2 cache

Instantiate the L2 cache from DT. Indicate in DT where the cache
control register is so that it is possible to enable/disable write
through on the CPU.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

Documentation/devicetree/bindings/arm/mrvl/feroceon.txt

+* Marvell Feroceon Cache
+
+Required properties:
+- compatible : Should be either "marvell,feroceon-cache" or
+  	       "marvell,kirkwood-cache".
+
+Optional properties:
+- reg        : Address of the L2 cache control register. Mandatory for
+  	       "marvell,kirkwood-cache", not used by "marvell,feroceon-cache"
+
+
+Example:
+		l2: l2-cache@20128 {
+			compatible = "marvell,kirkwood-cache";
+			reg = <0x20128 0x4>;
+		};

arch/arm/include/asm/hardware/cache-feroceon-l2.h

@@ -9,3 +9,5 @@
  */
 
 extern void __init feroceon_l2_init(int l2_wt_override);
+extern int __init feroceon_of_init(void);
+

arch/arm/mach-kirkwood/board-dt.c

@@ -42,19 +42,6 @@ static void __init kirkwood_map_io(void)
 	iotable_init(kirkwood_io_desc, ARRAY_SIZE(kirkwood_io_desc));
 }
 
-static void __init kirkwood_l2_init(void)
-{
-#ifdef CONFIG_CACHE_FEROCEON_L2
-#ifdef CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH
-	writel(readl(L2_CONFIG_REG) | L2_WRITETHROUGH, L2_CONFIG_REG);
-	feroceon_l2_init(1);
-#else
-	writel(readl(L2_CONFIG_REG) & ~L2_WRITETHROUGH, L2_CONFIG_REG);
-	feroceon_l2_init(0);
-#endif
-#endif
-}
-
 static struct resource kirkwood_cpufreq_resources[] = {
 	[0] = {
 		.start  = CPU_CONTROL_PHYS,
@@ -211,8 +198,9 @@ static void __init kirkwood_dt_init(void)
 
 	BUG_ON(mvebu_mbus_dt_init());
 
-	kirkwood_l2_init();
-
+#ifdef CONFIG_CACHE_FEROCEON_L2
+	feroceon_of_init();
+#endif
 	kirkwood_cpufreq_init();
 	kirkwood_cpuidle_init();
 

arch/arm/mm/cache-feroceon-l2.c

@@ -13,11 +13,16 @@
  */
 
 #include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/highmem.h>
+#include <linux/io.h>
 #include <asm/cacheflush.h>
 #include <asm/cp15.h>
 #include <asm/hardware/cache-feroceon-l2.h>
 
+#define L2_WRITETHROUGH_KIRKWOOD	BIT(4)
+
 /*
  * Low-level cache maintenance operations.
  *
@@ -350,3 +355,41 @@ void __init feroceon_l2_init(int __l2_wt_override)
 	printk(KERN_INFO "Feroceon L2: Cache support initialised%s.\n",
 			 l2_wt_override ? ", in WT override mode" : "");
 }
+#ifdef CONFIG_OF
+static const struct of_device_id feroceon_ids[] __initconst = {
+	{ .compatible = "marvell,kirkwood-cache"},
+	{ .compatible = "marvell,feroceon-cache"},
+	{}
+};
+
+int __init feroceon_of_init(void)
+{
+	struct device_node *node;
+	void __iomem *base;
+	bool l2_wt_override = false;
+	struct resource res;
+
+#if defined(CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH)
+	l2_wt_override = true;
+#endif
+
+	node = of_find_matching_node(NULL, feroceon_ids);
+	if (node && of_device_is_compatible(node, "marvell,kirkwood-cache")) {
+		if (of_address_to_resource(node, 0, &res))
+			return -ENODEV;
+
+		base = ioremap(res.start, resource_size(&res));
+		if (!base)
+			return -ENOMEM;
+
+		if (l2_wt_override)
+			writel(readl(base) | L2_WRITETHROUGH_KIRKWOOD, base);
+		else
+			writel(readl(base) & ~L2_WRITETHROUGH_KIRKWOOD, base);
+	}
+
+	feroceon_l2_init(l2_wt_override);
+
+	return 0;
+}
+#endif