| Heinrich Schuchardt | 1a41ca4 | 2024-04-26 16:13:18 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | /* |
| 3 | * Bootmethod for distro boot via EFI |
| 4 | * |
| 5 | * Copyright 2021 Google LLC |
| 6 | * Written by Simon Glass <sjg@chromium.org> |
| 7 | */ |
| 8 | |
| 9 | #include <efi_loader.h> |
| 10 | #include <env.h> |
| 11 | #include <errno.h> |
| 12 | #include <log.h> |
| 13 | #include <string.h> |
| 14 | #include <vsprintf.h> |
| 15 | |
| 16 | /** |
| 17 | * distro_efi_get_fdt_name() - get the filename for reading the .dtb file |
| 18 | * |
| 19 | * @fname: buffer for filename |
| 20 | * @size: buffer size |
| 21 | * @seq: sequence number, to cycle through options (0=first) |
| 22 | * |
| 23 | * Returns: |
| 24 | * 0 on success, |
| 25 | * -ENOENT if the "fdtfile" env var does not exist, |
| 26 | * -EINVAL if there are no more options, |
| 27 | * -EALREADY if the control FDT should be used |
| 28 | */ |
| 29 | int efi_get_distro_fdt_name(char *fname, int size, int seq) |
| 30 | { |
| 31 | const char *fdt_fname; |
| 32 | const char *prefix; |
| 33 | |
| 34 | /* select the prefix */ |
| 35 | switch (seq) { |
| 36 | case 0: |
| 37 | /* this is the default */ |
| 38 | prefix = "/dtb"; |
| 39 | break; |
| 40 | case 1: |
| 41 | prefix = ""; |
| 42 | break; |
| 43 | case 2: |
| 44 | prefix = "/dtb/current"; |
| 45 | break; |
| 46 | default: |
| 47 | return log_msg_ret("pref", -EINVAL); |
| 48 | } |
| 49 | |
| 50 | fdt_fname = env_get("fdtfile"); |
| 51 | if (fdt_fname) { |
| 52 | snprintf(fname, size, "%s/%s", prefix, fdt_fname); |
| 53 | log_debug("Using device tree: %s\n", fname); |
| 54 | } else if (IS_ENABLED(CONFIG_OF_HAS_PRIOR_STAGE)) { |
| 55 | strcpy(fname, "<prior>"); |
| 56 | return log_msg_ret("pref", -EALREADY); |
| 57 | /* Use this fallback only for 32-bit ARM */ |
| 58 | } else if (IS_ENABLED(CONFIG_ARM) && !IS_ENABLED(CONFIG_ARM64)) { |
| 59 | const char *soc = env_get("soc"); |
| 60 | const char *board = env_get("board"); |
| 61 | const char *boardver = env_get("boardver"); |
| 62 | |
| 63 | /* cf the code in label_boot() which seems very complex */ |
| 64 | snprintf(fname, size, "%s/%s%s%s%s.dtb", prefix, |
| 65 | soc ? soc : "", soc ? "-" : "", board ? board : "", |
| 66 | boardver ? boardver : ""); |
| 67 | log_debug("Using default device tree: %s\n", fname); |
| 68 | } else { |
| 69 | return log_msg_ret("env", -ENOENT); |
| 70 | } |
| 71 | |
| 72 | return 0; |
| 73 | } |
| Heinrich Schuchardt | d9b2363 | 2024-04-26 16:13:21 +0200 | [diff] [blame] | 74 | |
| 75 | /** |
| 76 | * efi_load_distro_fdt() - load distro device-tree |
| 77 | * |
| 78 | * @fdt: on return device-tree, must be freed via efi_free_pages() |
| 79 | * @fdt_size: buffer size |
| 80 | */ |
| 81 | void efi_load_distro_fdt(void **fdt, efi_uintn_t *fdt_size) |
| 82 | { |
| 83 | struct efi_device_path *rem, *dp; |
| 84 | efi_status_t ret; |
| 85 | efi_handle_t device; |
| 86 | |
| 87 | *fdt = NULL; |
| 88 | |
| 89 | dp = efi_get_dp_from_boot(NULL); |
| 90 | if (!dp) |
| 91 | return; |
| 92 | device = efi_dp_find_obj(dp, NULL, &rem); |
| 93 | ret = efi_search_protocol(device, &efi_simple_file_system_protocol_guid, |
| 94 | NULL); |
| 95 | if (ret != EFI_SUCCESS) |
| 96 | goto err; |
| 97 | memcpy(rem, &END, sizeof(END)); |
| 98 | |
| 99 | /* try the various available names */ |
| 100 | for (int seq = 0; ; ++seq) { |
| 101 | struct efi_device_path *file; |
| 102 | char buf[255]; |
| 103 | |
| 104 | if (efi_get_distro_fdt_name(buf, sizeof(buf), seq)) |
| 105 | break; |
| 106 | file = efi_dp_from_file(dp, buf); |
| 107 | if (!file) |
| 108 | break; |
| 109 | ret = efi_load_image_from_path(true, file, fdt, fdt_size); |
| 110 | efi_free_pool(file); |
| 111 | if (ret == EFI_SUCCESS) |
| 112 | break; |
| 113 | } |
| 114 | |
| 115 | err: |
| 116 | efi_free_pool(dp); |
| 117 | } |