riscv: cpu: fu540: Add support for cpu fu540

Add SiFive fu540 cpu to support RISC-V arch

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>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/arch/riscv/cpu/fu540/Kconfig b/arch/riscv/cpu/fu540/Kconfig
new file mode 100644
index 0000000..e9302e8
--- /dev/null
+++ b/arch/riscv/cpu/fu540/Kconfig
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+
+config SIFIVE_FU540
+	bool
+	select ARCH_EARLY_INIT_R
+	imply CPU
+	imply CPU_RISCV
+	imply RISCV_TIMER
+	imply SIFIVE_CLINT if (RISCV_MMODE || SPL_RISCV_MMODE)
+	imply CMD_CPU
+	imply SPL_CPU_SUPPORT
+	imply SPL_OPENSBI
+	imply SPL_LOAD_FIT
diff --git a/arch/riscv/cpu/fu540/Makefile b/arch/riscv/cpu/fu540/Makefile
new file mode 100644
index 0000000..44700d9
--- /dev/null
+++ b/arch/riscv/cpu/fu540/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2020 SiFive, Inc
+# Pragnesh Patel <pragnesh.patel@sifive.com>
+
+obj-y += dram.o
+obj-y += cpu.o
diff --git a/arch/riscv/cpu/fu540/cpu.c b/arch/riscv/cpu/fu540/cpu.c
new file mode 100644
index 0000000..f13c189
--- /dev/null
+++ b/arch/riscv/cpu/fu540/cpu.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <irq_func.h>
+#include <asm/cache.h>
+
+/*
+ * cleanup_before_linux() is called just before we call linux
+ * it prepares the processor for linux
+ *
+ * we disable interrupt and caches.
+ */
+int cleanup_before_linux(void)
+{
+	disable_interrupts();
+
+	cache_flush();
+
+	return 0;
+}
diff --git a/arch/riscv/cpu/fu540/dram.c b/arch/riscv/cpu/fu540/dram.c
new file mode 100644
index 0000000..1dc77ef
--- /dev/null
+++ b/arch/riscv/cpu/fu540/dram.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <init.h>
+#include <linux/sizes.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int dram_init(void)
+{
+	return fdtdec_setup_mem_size_base();
+}
+
+int dram_init_banksize(void)
+{
+	return fdtdec_setup_memory_banksize();
+}
+
+ulong board_get_usable_ram_top(ulong total_size)
+{
+#ifdef CONFIG_64BIT
+	/*
+	 * Ensure that we run from first 4GB so that all
+	 * addresses used by U-Boot are 32bit addresses.
+	 *
+	 * This in-turn ensures that 32bit DMA capable
+	 * devices work fine because DMA mapping APIs will
+	 * provide 32bit DMA addresses only.
+	 */
+	if (gd->ram_top > SZ_4G)
+		return SZ_4G;
+#endif
+	return gd->ram_top;
+}