1 /*
2  * Copyright (c) 2016, NVIDIA CORPORATION.
3  *
4  * SPDX-License-Identifier: GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <fdt_support.h>
9 #include <fdtdec.h>
10 #include <asm/arch/tegra.h>
11 
12 DECLARE_GLOBAL_DATA_PTR;
13 
14 extern unsigned long nvtboot_boot_x0;
15 
16 /*
17  * A parsed version of /memory/reg from the DTB that is passed to U-Boot in x0.
18  *
19  * We only support up to two banks since that's all the binary  bootloader
20  * ever sets. We assume bank 0 is RAM below 4G and bank 1 is RAM  above 4G.
21  * This is all a fairly safe assumption, since the L4T kernel makes  the same
22  * assumptions, so the bootloader is unlikely to change.
23  *
24  * This is written to before relocation, and hence cannot be in .bss, since
25  * .bss overlaps the DTB that's appended to the U-Boot binary. The initializer
26  * forces this into .data and avoids this issue. This also has the nice side-
27  * effect of the content being valid after relocation.
28  */
29 static struct {
30 	u64 start;
31 	u64 size;
32 } ram_banks[2] = {{1}};
33 
34 int dram_init(void)
35 {
36 	unsigned int na, ns;
37 	const void *nvtboot_blob = (void *)nvtboot_boot_x0;
38 	int node, len, i;
39 	const u32 *prop;
40 
41 	memset(ram_banks, 0, sizeof(ram_banks));
42 
43 	na = fdtdec_get_uint(nvtboot_blob, 0, "#address-cells", 2);
44 	ns = fdtdec_get_uint(nvtboot_blob, 0, "#size-cells", 2);
45 
46 	node = fdt_path_offset(nvtboot_blob, "/memory");
47 	if (node < 0) {
48 		pr_err("Can't find /memory node in nvtboot DTB");
49 		hang();
50 	}
51 	prop = fdt_getprop(nvtboot_blob, node, "reg", &len);
52 	if (!prop) {
53 		pr_err("Can't find /memory/reg property in nvtboot DTB");
54 		hang();
55 	}
56 
57 	len /= (na + ns);
58 	if (len > ARRAY_SIZE(ram_banks))
59 		len = ARRAY_SIZE(ram_banks);
60 
61 	gd->ram_size = 0;
62 	for (i = 0; i < len; i++) {
63 		ram_banks[i].start = fdt_read_number(prop, na);
64 		prop += na;
65 		ram_banks[i].size = fdt_read_number(prop, ns);
66 		prop += ns;
67 		gd->ram_size += ram_banks[i].size;
68 	}
69 
70 	return 0;
71 }
72 
73 extern unsigned long nvtboot_boot_x0;
74 
75 int dram_init_banksize(void)
76 {
77 	int i;
78 
79 	for (i = 0; i < 2; i++) {
80 		gd->bd->bi_dram[i].start = ram_banks[i].start;
81 		gd->bd->bi_dram[i].size = ram_banks[i].size;
82 	}
83 
84 	return 0;
85 }
86 
87 ulong board_get_usable_ram_top(ulong total_size)
88 {
89 	return ram_banks[0].start + ram_banks[0].size;
90 }
91