'Bootloader Control Block' (BCB) is a well established term/acronym in the Android namespace which refers to a location in a dedicated raw (i.e. FS-unaware) flash (e.g. eMMC) partition, usually called "misc", which is used as media for exchanging messages between Android userspace (particularly recovery [1]) and an Android-capable bootloader.
On higher level, this allows implementing a subset of Android Bootloader Requirements [2], amongst which is the Android-specific bootloader flow [3]. Regardless how the latter is implemented in U-Boot ([3] being the most memorable example), reading/writing/dumping the BCB fields in the development process from inside the U-Boot is a convenient feature. Hence, make it available to the users.
Some usage examples of the new command recorded on R-Car H3ULCB-KF ('>>>' is an overlay on top of the original console output):
=> bcb bcb - Load/set/clear/test/dump/store Android BCB fields
Usage: bcb load <dev> <part> - load BCB from mmc <dev>:<part> bcb set <field> <val> - set BCB <field> to <val> bcb clear [<field>] - clear BCB <field> or all fields bcb test <field> <op> <val> - test BCB <field> against <val> bcb dump <field> - dump BCB <field> bcb store - store BCB back to mmc
Legend: <dev> - MMC device index containing the BCB partition <part> - MMC partition index or name containing the BCB <field> - one of {command,status,recovery,stage,reserved} <op> - the binary operator used in 'bcb test': '=' returns true if <val> matches the string stored in <field> '~' returns true if <val> matches a subset of <field>'s string <val> - string/text provided as input to bcb {set,test} NOTE: any ':' character in <val> will be replaced by line feed during 'bcb set' and used as separator by upper layers
=> bcb dump command Error: BCB not loaded!
Users must specify mmc device and partition before any other call
=> bcb load 1 misc => bcb load 1 1
The two calls are equivalent (assuming "misc" has index 1)
=> bcb dump command 00000000: 62 6f 6f 74 6f 6e 63 65 2d 73 68 65 6c 6c 00 72 bootonce-shell.r 00000010: 79 00 72 00 00 00 00 00 00 00 00 00 00 00 00 00 y.r.............
The output is in binary/string format for convenience The output size matches the size of inspected BCB field (32 bytes in case of 'command')
=> bcb test command = bootonce-shell && echo true true => bcb test command = bootonce-shell- && echo true => bcb test command = bootonce-shel && echo true
The '=' operator returns 'true' on perfect match
=> bcb test command ~ bootonce-shel && echo true true => bcb test command ~ bootonce-shell && echo true true
The '~' operator returns 'true' on substring match
=> bcb set command recovery => bcb dump command 00000000: 72 65 63 6f 76 65 72 79 00 73 68 65 6c 6c 00 72 recovery.shell.r 00000010: 79 00 72 00 00 00 00 00 00 00 00 00 00 00 00 00 y.r.............
The new value is NULL-terminated and stored in the BCB field
=> bcb set recovery "msg1:msg2:msg3" => bcb dump recovery 00000040: 6d 73 67 31 0a 6d 73 67 32 0a 6d 73 67 33 00 00 msg1.msg2.msg3.. 00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
--- snip --- Every ':' is replaced by line-feed '\n' (0xA). The latter is used as separator between individual commands by Android userspace
=> bcb store
Flush/store the BCB structure to MMC
[1] https://android.googlesource.com/platform/bootable/recovery [2] https://source.android.com/devices/bootloader [3] https://patchwork.ozlabs.org/patch/746835/ ("[U-Boot,5/6] Initial support for the Android Bootloader flow")
Signed-off-by: Eugeniu Rosca erosca@de.adit-jv.com --- v2: - [Heinrich Schuchardt] Implement sub-commands via U_BOOT_CMD_MKENT. - Polished the code. Ensured no warnings returned by sparse, smatch, `cppcheck --force --enable=all --inconclusive`, make W=1. - Tested on R-Car-H3-ES20 ULCB-KF.
v1: - https://patchwork.ozlabs.org/patch/1080395/ --- cmd/Kconfig | 17 +++ cmd/Makefile | 1 + cmd/bcb.c | 330 +++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 348 insertions(+) create mode 100644 cmd/bcb.c
diff --git a/cmd/Kconfig b/cmd/Kconfig index 0d36da2a5c43..495bc1052f50 100644 --- a/cmd/Kconfig +++ b/cmd/Kconfig @@ -631,6 +631,23 @@ config CMD_ADC Shows ADC device info and permit printing one-shot analog converted data from a named Analog to Digital Converter.
+config CMD_BCB + bool "bcb" + depends on MMC + depends on PARTITIONS + help + Read/modify/write the fields of Bootloader Control Block, usually + stored on the flash "misc" partition with its structure defined in: + https://android.googlesource.com/platform/bootable/recovery/+/master/ + bootloader_message/include/bootloader_message/bootloader_message.h + + Some real-life use-cases include (but are not limited to): + - Determine the "boot reason" (and act accordingly): + https://source.android.com/devices/bootloader/boot-reason + - Get/pass a list of commands from/to recovery: + https://android.googlesource.com/platform/bootable/recovery + - Inspect/dump the contents of the BCB fields + config CMD_BIND bool "bind/unbind - Bind or unbind a device to/from a driver" depends on DM diff --git a/cmd/Makefile b/cmd/Makefile index 7864fcf95c36..8f31b478eb1b 100644 --- a/cmd/Makefile +++ b/cmd/Makefile @@ -16,6 +16,7 @@ obj-$(CONFIG_CMD_ADC) += adc.o obj-$(CONFIG_CMD_ARMFLASH) += armflash.o obj-y += blk_common.o obj-$(CONFIG_CMD_SOURCE) += source.o +obj-$(CONFIG_CMD_BCB) += bcb.o obj-$(CONFIG_CMD_BDI) += bdinfo.o obj-$(CONFIG_CMD_BEDBUG) += bedbug.o obj-$(CONFIG_CMD_BIND) += bind.o diff --git a/cmd/bcb.c b/cmd/bcb.c new file mode 100644 index 000000000000..5d8486684542 --- /dev/null +++ b/cmd/bcb.c @@ -0,0 +1,330 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2019 Eugeniu Rosca rosca.eugeniu@gmail.com + * + * Command to read/modify/write Android BCB fields + */ + +#include <android_bootloader_message.h> +#include <command.h> +#include <common.h> +#include <malloc.h> + +enum bcb_cmd { + BCB_CMD_LOAD, + BCB_CMD_FIELD_SET, + BCB_CMD_FIELD_CLEAR, + BCB_CMD_FIELD_TEST, + BCB_CMD_FIELD_DUMP, + BCB_CMD_STORE, +}; + +static int bcb_dev = -1; +static int bcb_part = -1; +static struct bootloader_message bcb = { { 0 } }; + +static int bcb_cmd_get(char *cmd) +{ + if (!strncmp(cmd, "load", sizeof("load"))) + return BCB_CMD_LOAD; + if (!strncmp(cmd, "set", sizeof("set"))) + return BCB_CMD_FIELD_SET; + if (!strncmp(cmd, "clear", sizeof("clear"))) + return BCB_CMD_FIELD_CLEAR; + if (!strncmp(cmd, "test", sizeof("test"))) + return BCB_CMD_FIELD_TEST; + if (!strncmp(cmd, "store", sizeof("store"))) + return BCB_CMD_STORE; + if (!strncmp(cmd, "dump", sizeof("dump"))) + return BCB_CMD_FIELD_DUMP; + else + return -1; +} + +static int do_bcb_load(cmd_tbl_t *cmdtp, int flag, int argc, + char * const argv[]) +{ + struct blk_desc *desc; + disk_partition_t info; + u64 cnt; + char *endp; + int part; + + if (argc != 3) + return CMD_RET_USAGE; + + if (blk_get_device_by_str("mmc", argv[1], &desc) < 0) + goto err_1; + + part = simple_strtoul(argv[2], &endp, 0); + if (*endp == '\0') { + if (part_get_info(desc, part, &info)) + goto err_1; + } else { + part = part_get_info_by_name(desc, argv[2], &info); + if (part < 0) + goto err_1; + } + + cnt = DIV_ROUND_UP(sizeof(struct bootloader_message), info.blksz); + if (cnt > info.size) + goto err_2; + + if (blk_dread(desc, info.start, cnt, &bcb) != cnt) + goto err_1; + + bcb_dev = desc->devnum; + bcb_part = part; + debug("%s: Loaded from mmc %d:%d\n", __func__, bcb_dev, bcb_part); + + return CMD_RET_SUCCESS; +err_1: + printf("Error: Failed to read from mmc %s:%s\n", argv[1], argv[2]); + goto err; +err_2: + printf("Error: mmc %s:%s too small!", argv[1], argv[2]); + goto err; +err: + bcb_dev = -1; + bcb_part = -1; + return CMD_RET_FAILURE; +} + +static int bcb_is_misused(int argc, char *const argv[]) +{ + if (bcb_dev < 0 || bcb_part < 0) { + printf("Error: BCB not loaded!\n"); + return -1; + } + switch (bcb_cmd_get(argv[0])) { + case BCB_CMD_LOAD: + /* Dedicated arg handling */ + break; + case BCB_CMD_FIELD_SET: + if (argc != 3) + goto err; + break; + case BCB_CMD_FIELD_TEST: + if (argc != 4) + goto err; + break; + case BCB_CMD_FIELD_CLEAR: + if (argc != 1 && argc != 2) + goto err; + break; + case BCB_CMD_STORE: + if (argc != 1) + goto err; + break; + case BCB_CMD_FIELD_DUMP: + if (argc != 2) + goto err; + break; + default: + debug("%s: Error: Unexpected BCB command\n", __func__); + return -1; + } + + return 0; +err: + printf("Error: Bad usage of 'bcb %s'\n", argv[0]); + return -1; +} + +static int +bcb_field_get(char *name, char **field, int *size) +{ + if (!strncmp(name, "command", sizeof("command"))) { + *field = bcb.command; + *size = sizeof(bcb.command); + } else if (!strncmp(name, "status", sizeof("status"))) { + *field = bcb.status; + *size = sizeof(bcb.status); + } else if (!strncmp(name, "recovery", sizeof("recovery"))) { + *field = bcb.recovery; + *size = sizeof(bcb.recovery); + } else if (!strncmp(name, "stage", sizeof("stage"))) { + *field = bcb.stage; + *size = sizeof(bcb.stage); + } else if (!strncmp(name, "reserved", sizeof("reserved"))) { + *field = bcb.reserved; + *size = sizeof(bcb.reserved); + } else { + printf("Error: Unknown field '%s'\n", name); + return -1; + } + return 0; +} + +static int do_bcb_set(cmd_tbl_t *cmdtp, int flag, int argc, + char * const argv[]) +{ + int size, len; + char *field, *str, *found, *keep; + + if (bcb_is_misused(argc, argv)) + return CMD_RET_FAILURE; + + if (bcb_field_get(argv[1], &field, &size)) + return CMD_RET_FAILURE; + + len = strlen(argv[2]); + if (len >= size) { + printf("Error: sizeof('%s') = %d >= %d = sizeof(bcb.%s)\n", + argv[2], len, size, argv[1]); + return CMD_RET_FAILURE; + } + str = strdup(argv[2]); + keep = str; + + field[0] = '\0'; + while ((found = strsep(&str, ":"))) { + if (field[0] != '\0') + strcat(field, "\n"); + strcat(field, found); + } + + free(keep); + return CMD_RET_SUCCESS; +} + +static int do_bcb_clear(cmd_tbl_t *cmdtp, int flag, int argc, + char * const argv[]) +{ + int size; + char *field; + + if (bcb_is_misused(argc, argv)) + return CMD_RET_FAILURE; + + if (argc == 1) { + memset(&bcb, 0, sizeof(bcb)); + return CMD_RET_SUCCESS; + } + + if (bcb_field_get(argv[1], &field, &size)) + return CMD_RET_FAILURE; + + memset(field, 0, size); + return CMD_RET_SUCCESS; +} + +static int do_bcb_dump(cmd_tbl_t *cmdtp, int flag, int argc, + char * const argv[]) +{ + int size; + char *field; + + if (bcb_is_misused(argc, argv)) + return CMD_RET_FAILURE; + + if (bcb_field_get(argv[1], &field, &size)) + return CMD_RET_FAILURE; + + print_buffer((ulong)field - (ulong)&bcb, (void *)field, 1, size, 16); + return CMD_RET_SUCCESS; +} + +static int do_bcb_test(cmd_tbl_t *cmdtp, int flag, int argc, + char * const argv[]) +{ + int size; + char *field; + + if (bcb_is_misused(argc, argv)) + return CMD_RET_FAILURE; + + if (bcb_field_get(argv[1], &field, &size)) + return CMD_RET_FAILURE; + + if (!strncmp(argv[2], "=", sizeof("="))) { + if (!strncmp(argv[3], field, size)) + return CMD_RET_SUCCESS; + else + return CMD_RET_FAILURE; + } else if (!strncmp(argv[2], "~", sizeof("~"))) { + if (!strstr(field, argv[3])) + return CMD_RET_FAILURE; + else + return CMD_RET_SUCCESS; + } else { + printf("Error: Unknown operator '%s'\n", argv[2]); + } + return CMD_RET_FAILURE; +} + +static int do_bcb_store(cmd_tbl_t *cmdtp, int flag, int argc, + char * const argv[]) +{ + struct blk_desc *desc; + disk_partition_t info; + u64 cnt; + + if (bcb_is_misused(argc, argv)) + return CMD_RET_FAILURE; + + desc = blk_get_devnum_by_type(IF_TYPE_MMC, bcb_dev); + if (!desc) + goto err; + + if (part_get_info(desc, bcb_part, &info)) + goto err; + + cnt = DIV_ROUND_UP(sizeof(struct bootloader_message), info.blksz); + + if (blk_dwrite(desc, info.start, cnt, &bcb) != cnt) + goto err; + + return CMD_RET_SUCCESS; +err: + printf("Error: Failed to write to mmc %d:%d\n", bcb_dev, bcb_part); + return CMD_RET_FAILURE; +} + +static cmd_tbl_t cmd_bcb_sub[] = { + U_BOOT_CMD_MKENT(load, CONFIG_SYS_MAXARGS, 1, do_bcb_load, "", ""), + U_BOOT_CMD_MKENT(set, CONFIG_SYS_MAXARGS, 1, do_bcb_set, "", ""), + U_BOOT_CMD_MKENT(clear, CONFIG_SYS_MAXARGS, 1, do_bcb_clear, "", ""), + U_BOOT_CMD_MKENT(test, CONFIG_SYS_MAXARGS, 1, do_bcb_test, "", ""), + U_BOOT_CMD_MKENT(dump, CONFIG_SYS_MAXARGS, 1, do_bcb_dump, "", ""), + U_BOOT_CMD_MKENT(store, CONFIG_SYS_MAXARGS, 1, do_bcb_store, "", ""), +}; + +static int do_bcb(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[]) +{ + cmd_tbl_t *c; + + if (argc < 2) + return CMD_RET_USAGE; + + argc--; + argv++; + + c = find_cmd_tbl(argv[0], cmd_bcb_sub, ARRAY_SIZE(cmd_bcb_sub)); + if (c) + return c->cmd(cmdtp, flag, argc, argv); + + return CMD_RET_USAGE; +} + +U_BOOT_CMD( + bcb, CONFIG_SYS_MAXARGS, 1, do_bcb, + "Load/set/clear/test/dump/store Android BCB fields", + "load <dev> <part> - load BCB from mmc <dev>:<part>\n" + "bcb set <field> <val> - set BCB <field> to <val>\n" + "bcb clear [<field>] - clear BCB <field> or all fields\n" + "bcb test <field> <op> <val> - test BCB <field> against <val>\n" + "bcb dump <field> - dump BCB <field>\n" + "bcb store - store BCB back to mmc\n" + "\n" + "Legend:\n" + "<dev> - MMC device index containing the BCB partition\n" + "<part> - MMC partition index or name containing the BCB\n" + "<field> - one of {command,status,recovery,stage,reserved}\n" + "<op> - the binary operator used in 'bcb test':\n" + " '=' returns true if <val> matches the string stored in <field>\n" + " '~' returns true if <val> matches a subset of <field>'s string\n" + "<val> - string/text provided as input to bcb {set,test}\n" + " NOTE: any ':' character in <val> will be replaced by line feed\n" + " during 'bcb set' and used as separator by upper layers\n" +);