xref: /openbmc/u-boot/arch/riscv/cpu/generic/dram.c (revision fd0bc623)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
4  */
5 
6 #include <common.h>
7 #include <fdtdec.h>
8 #include <linux/sizes.h>
9 
10 DECLARE_GLOBAL_DATA_PTR;
11 
12 int dram_init(void)
13 {
14 	return fdtdec_setup_mem_size_base();
15 }
16 
17 int dram_init_banksize(void)
18 {
19 	return fdtdec_setup_memory_banksize();
20 }
21 
22 ulong board_get_usable_ram_top(ulong total_size)
23 {
24 #ifdef CONFIG_64BIT
25 	/*
26 	 * Ensure that we run from first 4GB so that all
27 	 * addresses used by U-Boot are 32bit addresses.
28 	 *
29 	 * This in-turn ensures that 32bit DMA capable
30 	 * devices work fine because DMA mapping APIs will
31 	 * provide 32bit DMA addresses only.
32 	 */
33 	if (gd->ram_top > SZ_4G)
34 		return SZ_4G;
35 #endif
36 	return gd->ram_top;
37 }
38