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>

arch/riscv/cpu/fu540/Makefile

@@ -8,4 +8,5 @@ obj-y += spl.o
 else
 obj-y += dram.o
 obj-y += cpu.o
+obj-y += cache.o
 endif

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;
+}

arch/riscv/dts/fu540-c000-u-boot.dtsi

@@ -87,3 +87,7 @@
 	assigned-clocks = <&prci PRCI_CLK_GEMGXLPLL>;
 	assigned-clock-rates = <125000000>;
 };
+
+&l2cache {
+	status = "okay";
+};

arch/riscv/include/asm/arch-fu540/cache.h

@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2020 SiFive, Inc.
+ *
+ * Authors:
+ *   Pragnesh Patel <pragnesh.patel@sifve.com>
+ */
+
+#ifndef _CACHE_SIFIVE_H
+#define _CACHE_SIFIVE_H
+
+int cache_enable_ways(void);
+
+#endif /* _CACHE_SIFIVE_H */

board/sifive/fu540/fu540.c

@@ -15,6 +15,7 @@
 #include <linux/io.h>
 #include <misc.h>
 #include <spl.h>
+#include <asm/arch/cache.h>
 
 /*
  * This define is a value used for error/unknown serial.
@@ -114,7 +115,14 @@ int misc_init_r(void)
 
 int board_init(void)
 {
-	/* For now nothing to do here. */
+	int ret;
+
+	/* enable all cache ways */
+	ret = cache_enable_ways();
+	if (ret) {
+		debug("%s: could not enable cache ways\n", __func__);
+		return ret;
+	}
 
 	return 0;
 }