riscv: spacemit: bananapi_f3: initial support added

Add basic support for SpacemiT's Banana Pi F3 board.
Update the k1.dtsi align with mainline.
Note that the device tree files follow the mainline Linux source[1].

Links: https://patches.linaro.org/project/linux-serial/patch/20240730-k1-01-basic-dt-v5-8-98263aae83be@gentoo.org/ [1]

Signed-off-by: Kongyang Liu <seashell11234455@gmail.com>
Signed-off-by: Huan Zhou <pericycle.cc@gmail.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Yixun Lan <dlan@gentoo.org>
Tested-by: Marcel Ziswiler <marcel@ziswiler.com>
diff --git a/arch/riscv/cpu/k1/dram.c b/arch/riscv/cpu/k1/dram.c
new file mode 100644
index 0000000..c477c15
--- /dev/null
+++ b/arch/riscv/cpu/k1/dram.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2024, Kongyang Liu <seashell11234455@gmail.com>
+ */
+
+#include <asm/global_data.h>
+#include <config.h>
+#include <fdt_support.h>
+#include <linux/sizes.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int dram_init(void)
+{
+	gd->ram_base = CFG_SYS_SDRAM_BASE;
+	/* TODO get ram size from ddr controller */
+	gd->ram_size = SZ_4G;
+	return 0;
+}
+
+int dram_init_banksize(void)
+{
+	gd->bd->bi_dram[0].start = CFG_SYS_SDRAM_BASE;
+	gd->bd->bi_dram[0].size = min_t(phys_size_t, gd->ram_size, SZ_2G);
+
+	if (gd->ram_size > SZ_2G && CONFIG_NR_DRAM_BANKS > 1) {
+		gd->bd->bi_dram[1].start = 0x100000000;
+		gd->bd->bi_dram[1].size = gd->ram_size - SZ_2G;
+	}
+
+	return 0;
+}
+
+phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
+{
+	if (gd->ram_size > SZ_2G)
+		return SZ_2G;
+
+	return gd->ram_size;
+}
+
+int ft_board_setup(void *blob, struct bd_info *bd)
+{
+	u64 start[CONFIG_NR_DRAM_BANKS];
+	u64 size[CONFIG_NR_DRAM_BANKS];
+	int i;
+
+	for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
+		start[i] = gd->bd->bi_dram[i].start;
+		size[i] = gd->bd->bi_dram[i].size;
+	}
+
+	return fdt_fixup_memory_banks(blob, start, size, CONFIG_NR_DRAM_BANKS);
+}