1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * save_prev_bl_data - saving previous bootloader data
4 * to environment variables.
5 *
6 * Copyright (c) 2022 Dzmitry Sankouski (dsankouski@gmail.com)
7 */
8 #include <init.h>
9 #include <env.h>
10 #include <fdtdec.h>
11 #include <fdt_support.h>
12 #include <fdt.h>
13 #include <common.h>
14 #include <linux/errno.h>
15 #include <asm/system.h>
16 #include <asm/armv8/mmu.h>
17
18 static ulong reg0 __section(".data");
19
20 /**
21 * Save x0 register value, assuming previous bootloader set it to
22 * point on loaded fdt or (for older linux kernels)atags.
23 */
save_boot_params(ulong r0)24 void save_boot_params(ulong r0)
25 {
26 reg0 = r0;
27 save_boot_params_ret();
28 }
29
is_addr_accessible(phys_addr_t addr)30 bool is_addr_accessible(phys_addr_t addr)
31 {
32 struct mm_region *mem = mem_map;
33 phys_addr_t bank_start;
34 phys_addr_t bank_end;
35
36 while (mem->size) {
37 bank_start = mem->phys;
38 bank_end = bank_start + mem->size;
39 debug("check if block %pap - %pap includes %pap\n", &bank_start, &bank_end, &addr);
40 if (addr > bank_start && addr < bank_end)
41 return true;
42 mem++;
43 }
44
45 return false;
46 }
47
save_prev_bl_data(void)48 int save_prev_bl_data(void)
49 {
50 struct fdt_header *fdt_blob;
51 int node;
52 u64 initrd_start_prop;
53
54 if (!is_addr_accessible((phys_addr_t)reg0))
55 return -ENODATA;
56
57 fdt_blob = (struct fdt_header *)reg0;
58 if (!fdt_valid(&fdt_blob)) {
59 pr_warn("%s: address 0x%lx is not a valid fdt\n", __func__, reg0);
60 return -ENODATA;
61 }
62
63 if (IS_ENABLED(CONFIG_SAVE_PREV_BL_FDT_ADDR))
64 env_set_addr("prevbl_fdt_addr", (void *)reg0);
65 if (!IS_ENABLED(CONFIG_SAVE_PREV_BL_INITRAMFS_START_ADDR))
66 return 0;
67
68 node = fdt_path_offset(fdt_blob, "/chosen");
69 if (!node) {
70 pr_warn("%s: chosen node not found in device tree at addr: 0x%lx\n",
71 __func__, reg0);
72 return -ENODATA;
73 }
74 /*
75 * linux,initrd-start property might be either 64 or 32 bit,
76 * depending on primary bootloader implementation.
77 */
78 initrd_start_prop = fdtdec_get_uint64(fdt_blob, node, "linux,initrd-start", 0);
79 if (!initrd_start_prop) {
80 debug("%s: attempt to get uint64 linux,initrd-start property failed, trying uint\n",
81 __func__);
82 initrd_start_prop = fdtdec_get_uint(fdt_blob, node, "linux,initrd-start", 0);
83 if (!initrd_start_prop) {
84 debug("%s: attempt to get uint failed, too\n", __func__);
85 return -ENODATA;
86 }
87 }
88 env_set_addr("prevbl_initrd_start_addr", (void *)initrd_start_prop);
89
90 return 0;
91 }
92