cmd: bcb: introduce 'ab_dump' command to print BCB block content

It's really helpful to have the ability to dump BCB block for debugging
A/B logic on the board supported this partition schema.

Command 'bcb ab_dump' prints all fields of bootloader_control struct
including slot_metadata for all presented slots.

Output example:
=====
> board# bcb ab_dump ubi 0#misc
> Read 512 bytes from volume misc to 000000000bf07580
> Read 512 bytes from volume misc to 000000000bf42f40
> Bootloader Control:       [misc]
> Active Slot:              _a
> Magic Number:             0x42414342
> Version:                  1
> Number of Slots:          2
> Recovery Tries Remaining: 0
> CRC:                      0x2c8b50bc (Valid)
>
> Slot[0] Metadata:
> 	- Priority:         15
> 	- Tries Remaining:  0
> 	- Successful Boot:  1
> 	- Verity Corrupted: 0
>
> Slot[1] Metadata:
> 	- Priority:         14
> 	- Tries Remaining:  7
> 	- Successful Boot:  0
> 	- Verity Corrupted: 0
====

The ab_dump command allows you to display ABC data directly on the
U-Boot console. During an A/B test execution, this test verifies the
accuracy of each field within the ABC data.

Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Tested-by: Mattijs Korpershoek <mkorpershoek@baylibre.com> # vim3_android
Link: https://lore.kernel.org/r/20241017-android_ab_master-v5-5-43bfcc096d95@salutedevices.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>

boot/android_ab.c

@@ -372,3 +372,71 @@ int ab_select_slot(struct blk_desc *dev_desc, struct disk_partition *part_info,
 
 	return slot;
 }
+
+int ab_dump_abc(struct blk_desc *dev_desc, struct disk_partition *part_info)
+{
+	struct bootloader_control *abc;
+	u32 crc32_le;
+	int i, ret;
+	struct slot_metadata *slot;
+
+	if (!dev_desc || !part_info) {
+		log_err("ANDROID: Empty device descriptor or partition info\n");
+		return -EINVAL;
+	}
+
+	ret = ab_control_create_from_disk(dev_desc, part_info, &abc, 0);
+	if (ret < 0) {
+		log_err("ANDROID: Cannot create bcb from disk %d\n", ret);
+		return ret;
+	}
+
+	if (abc->magic != BOOT_CTRL_MAGIC) {
+		log_err("ANDROID: Unknown A/B metadata: %.8x\n", abc->magic);
+		ret = -ENODATA;
+		goto error;
+	}
+
+	if (abc->version > BOOT_CTRL_VERSION) {
+		log_err("ANDROID: Unsupported A/B metadata version: %.8x\n",
+			abc->version);
+		ret = -ENODATA;
+		goto error;
+	}
+
+	if (abc->nb_slot > ARRAY_SIZE(abc->slot_info)) {
+		log_err("ANDROID: Wrong number of slots %u, expected %zu\n",
+			abc->nb_slot, ARRAY_SIZE(abc->slot_info));
+		ret = -ENODATA;
+		goto error;
+	}
+
+	printf("Bootloader Control:       [%s]\n", part_info->name);
+	printf("Active Slot:              %s\n", abc->slot_suffix);
+	printf("Magic Number:             0x%x\n", abc->magic);
+	printf("Version:                  %u\n", abc->version);
+	printf("Number of Slots:          %u\n", abc->nb_slot);
+	printf("Recovery Tries Remaining: %u\n", abc->recovery_tries_remaining);
+
+	printf("CRC:                      0x%.8x", abc->crc32_le);
+
+	crc32_le = ab_control_compute_crc(abc);
+	if (abc->crc32_le != crc32_le)
+		printf(" (Invalid, Expected: 0x%.8x)\n", crc32_le);
+	else
+		printf(" (Valid)\n");
+
+	for (i = 0; i < abc->nb_slot; ++i) {
+		slot = &abc->slot_info[i];
+		printf("\nSlot[%d] Metadata:\n", i);
+		printf("\t- Priority:         %u\n", slot->priority);
+		printf("\t- Tries Remaining:  %u\n", slot->tries_remaining);
+		printf("\t- Successful Boot:  %u\n", slot->successful_boot);
+		printf("\t- Verity Corrupted: %u\n", slot->verity_corrupted);
+	}
+
+error:
+	free(abc);
+
+	return ret;
+}

cmd/bcb.c

@@ -419,6 +419,32 @@ __maybe_unused static int do_bcb_ab_select(struct cmd_tbl *cmdtp,
 	return CMD_RET_SUCCESS;
 }
 
+__maybe_unused static int do_bcb_ab_dump(struct cmd_tbl *cmdtp,
+					 int flag, int argc,
+					 char *const argv[])
+{
+	int ret;
+	struct blk_desc *dev_desc;
+	struct disk_partition part_info;
+
+	if (argc < 3)
+		return CMD_RET_USAGE;
+
+	if (part_get_info_by_dev_and_name_or_num(argv[1], argv[2],
+						 &dev_desc, &part_info,
+						 false) < 0) {
+		return CMD_RET_FAILURE;
+	}
+
+	ret = ab_dump_abc(dev_desc, &part_info);
+	if (ret < 0) {
+		printf("Cannot dump ABC data, error %d.\n", ret);
+		return CMD_RET_FAILURE;
+	}
+
+	return CMD_RET_SUCCESS;
+}
+
 U_BOOT_LONGHELP(bcb,
 	"load <interface> <dev> <part>  - load  BCB from <interface> <dev>:<part>\n"
 	"load <dev> <part>              - load  BCB from mmc <dev>:<part>\n"
@@ -444,6 +470,10 @@ U_BOOT_LONGHELP(bcb,
 	"    - If '--no-dec' is set, the number of tries remaining will not\n"
 	"      decremented for the selected boot slot\n"
 	"\n"
+	"bcb ab_dump -\n"
+	"    Dump boot_control information from specific partition.\n"
+	"    <interface> <dev[:part|#part_name]>\n"
+	"\n"
 #endif
 	"Legend:\n"
 	"<interface> - storage device interface (virtio, mmc, etc)\n"
@@ -468,5 +498,6 @@ U_BOOT_CMD_WITH_SUBCMDS(bcb,
 	U_BOOT_SUBCMD_MKENT(store, 1, 1, do_bcb_store),
 #if IS_ENABLED(CONFIG_ANDROID_AB)
 	U_BOOT_SUBCMD_MKENT(ab_select, 5, 1, do_bcb_ab_select),
+	U_BOOT_SUBCMD_MKENT(ab_dump, 3, 1, do_bcb_ab_dump),
 #endif
 );

include/android_ab.h

@@ -36,4 +36,14 @@ struct disk_partition;
 int ab_select_slot(struct blk_desc *dev_desc, struct disk_partition *part_info,
                    bool dec_tries);
 
+/**
+ * ab_dump_abc() - Dump ABC information for specific partition.
+ *
+ * @dev_desc: Device description pointer
+ * @part_info: Partition information
+ *
+ * Return: 0 on success, or a negative on error
+ */
+int ab_dump_abc(struct blk_desc *dev_desc, struct disk_partition *part_info);
+
 #endif /* __ANDROID_AB_H */

test/py/tests/test_android/test_ab.py

@@ -54,6 +54,27 @@ def ab_disk_image(u_boot_console):
         di = ABTestDiskImage(u_boot_console)
     return di
 
+def ab_dump(u_boot_console, slot_num, crc):
+    output = u_boot_console.run_command('bcb ab_dump host 0#misc')
+    header, slot0, slot1 = output.split('\r\r\n\r\r\n')
+    slots = [slot0, slot1]
+    slot_suffixes = ['_a', '_b']
+
+    header = dict(map(lambda x: map(str.strip, x.split(':')), header.split('\r\r\n')))
+    assert header['Bootloader Control'] == '[misc]'
+    assert header['Active Slot'] == slot_suffixes[slot_num]
+    assert header['Magic Number'] == '0x42414342'
+    assert header['Version'] == '1'
+    assert header['Number of Slots'] == '2'
+    assert header['Recovery Tries Remaining'] == '0'
+    assert header['CRC'] == '{} (Valid)'.format(crc)
+
+    slot = dict(map(lambda x: map(str.strip, x.split(':')), slots[slot_num].split('\r\r\n\t- ')[1:]))
+    assert slot['Priority'] == '15'
+    assert slot['Tries Remaining'] == '6'
+    assert slot['Successful Boot'] == '0'
+    assert slot['Verity Corrupted'] == '0'
+
 @pytest.mark.boardspec('sandbox')
 @pytest.mark.buildconfigspec('android_ab')
 @pytest.mark.buildconfigspec('cmd_bcb')
@@ -68,8 +89,10 @@ def test_ab(ab_disk_image, u_boot_console):
     assert 'Attempting slot a, tries remaining 7' in output
     output = u_boot_console.run_command('printenv slot_name')
     assert 'slot_name=a' in output
+    ab_dump(u_boot_console, 0, '0xd438d1b9')
 
     output = u_boot_console.run_command('bcb ab_select slot_name host 0:1')
     assert 'Attempting slot b, tries remaining 7' in output
     output = u_boot_console.run_command('printenv slot_name')
     assert 'slot_name=b' in output
+    ab_dump(u_boot_console, 1, '0x011ec016')