[U-Boot] [PATCH v2 2/2] cmd: Add 'bcb' command to read/modify/write BCB fields
Eugeniu Rosca
erosca at de.adit-jv.com
Fri May 17 14:45:03 UTC 2019
'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 at 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 at 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"
+);
--
2.21.0
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