riscv: sifive: fu540: enable all cache ways from U-Boot proper

Add L2 cache node to enable all cache ways from U-Boot proper.

Signed-off-by: Pragnesh Patel <pragnesh.patel@sifive.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/riscv/cpu/fu540/cache.c b/arch/riscv/cpu/fu540/cache.c
new file mode 100644
index 0000000..9ee364b
--- /dev/null
+++ b/arch/riscv/cpu/fu540/cache.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 SiFive, Inc
+ *
+ * Authors:
+ *   Pragnesh Patel <pragnesh.patel@sifive.com>
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <linux/bitops.h>
+
+/* Register offsets */
+#define L2_CACHE_CONFIG	0x000
+#define L2_CACHE_ENABLE	0x008
+
+#define MASK_NUM_WAYS	GENMASK(15, 8)
+#define NUM_WAYS_SHIFT	8
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int cache_enable_ways(void)
+{
+	const void *blob = gd->fdt_blob;
+	int node = (-FDT_ERR_NOTFOUND);
+	fdt_addr_t base;
+	u32 config;
+	u32 ways;
+
+	volatile u32 *enable;
+
+	node = fdt_node_offset_by_compatible(blob, -1,
+					     "sifive,fu540-c000-ccache");
+
+	if (node < 0)
+		return node;
+
+	base = fdtdec_get_addr(blob, node, "reg");
+	if (base == FDT_ADDR_T_NONE)
+		return FDT_ADDR_T_NONE;
+
+	config = readl((volatile u32 *)base + L2_CACHE_CONFIG);
+	ways = (config & MASK_NUM_WAYS) >> NUM_WAYS_SHIFT;
+
+	enable = (volatile u32 *)(base + L2_CACHE_ENABLE);
+
+	/* memory barrier */
+	mb();
+	(*enable) = ways - 1;
+	/* memory barrier */
+	mb();
+	return 0;
+}