platform: generic: Move Sifive platform overrides into own directory

Let us move SiFive platform overrides for FU540 and FU740 into a separate
directory so better maintainability. Other SoC vendors can also create
their own directory under platform/generic.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>

platform/generic/sifive/fu540.c

@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <platform_override.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/fdt/fdt_fixup.h>
+
+static u64 sifive_fu540_tlbr_flush_limit(const struct fdt_match *match)
+{
+	/*
+	 * The sfence.vma by virtual address does not work on
+	 * SiFive FU540 so we return remote TLB flush limit as zero.
+	 */
+	return 0;
+}
+
+static int sifive_fu540_fdt_fixup(void *fdt, const struct fdt_match *match)
+{
+	/*
+	 * SiFive Freedom U540 has an erratum that prevents S-mode software
+	 * to access a PMP protected region using 1GB page table mapping, so
+	 * always add the no-map attribute on this platform.
+	 */
+	fdt_reserved_memory_nomap_fixup(fdt);
+
+	return 0;
+}
+
+static const struct fdt_match sifive_fu540_match[] = {
+	{ .compatible = "sifive,fu540" },
+	{ .compatible = "sifive,fu540g" },
+	{ .compatible = "sifive,fu540-c000" },
+	{ .compatible = "sifive,hifive-unleashed-a00" },
+	{ },
+};
+
+const struct platform_override sifive_fu540 = {
+	.match_table = sifive_fu540_match,
+	.tlbr_flush_limit = sifive_fu540_tlbr_flush_limit,
+	.fdt_fixup = sifive_fu540_fdt_fixup,
+};