cmd: Add 'ab_select' command

For A/B system update support the Android boot process requires to send
'androidboot.slot_suffix' parameter as a command line argument. This
patch implementes 'ab_select' command which allows us to obtain current
slot by processing the A/B metadata.

The patch was extracted from commit [1] with one modification: the
separator for specifying the name of metadata partition was changed
from ';' to '#', because ';' is used for commands separation.

[1] https://android-review.googlesource.com/c/platform/external/u-boot/+/729880/2

Signed-off-by: Ruslan Trofymenko <ruslan.trofymenko@linaro.org>
Signed-off-by: Igor Opaniuk <igor.opaniuk@gmail.com>
Reviewed-by: Alistair Strachan <astrachan@google.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/cmd/Kconfig b/cmd/Kconfig
index e1e050f..9e66cc1 100644 (file)
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1198,6 +1198,21 @@ config CMD_SETEXPR
 
 endmenu
 
+menu "Android support commands"
+
+config CMD_AB_SELECT
+       bool "ab_select"
+       default n
+       depends on ANDROID_AB
+       help
+         On Android devices with more than one boot slot (multiple copies of
+         the kernel and system images) this provides a command to select which
+         slot should be used to boot from and register the boot attempt. This
+         is used by the new A/B update model where one slot is updated in the
+         background while running from the other slot.
+
+endmenu
+
 if NET
 
 menuconfig CMD_NET

diff --git a/cmd/Makefile b/cmd/Makefile
index 0aa3741..43a6b0e 100644 (file)
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -12,6 +12,7 @@ obj-y += version.o
 
 # command
 obj-$(CONFIG_CMD_AES) += aes.o
+obj-$(CONFIG_CMD_AB_SELECT) += ab_select.o
 obj-$(CONFIG_CMD_ADC) += adc.o
 obj-$(CONFIG_CMD_ARMFLASH) += armflash.o
 obj-y += blk_common.o

diff --git a/cmd/ab_select.c b/cmd/ab_select.c
new file mode 100644 (file)
index 0000000..7c8f2ee
--- /dev/null
+++ b/cmd/ab_select.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ */
+
+#include <android_ab.h>
+#include <command.h>
+
+static int do_ab_select(cmd_tbl_t *cmdtp, int flag, int argc,
+                       char * const argv[])
+{
+       int ret;
+       struct blk_desc *dev_desc;
+       disk_partition_t part_info;
+       char slot[2];
+
+       if (argc != 4)
+               return CMD_RET_USAGE;
+
+       /* Lookup the "misc" partition from argv[2] and argv[3] */
+       if (part_get_info_by_dev_and_name_or_num(argv[2], argv[3],
+                                                &dev_desc, &part_info) < 0) {
+               return CMD_RET_FAILURE;
+       }
+
+       ret = ab_select_slot(dev_desc, &part_info);
+       if (ret < 0) {
+               printf("Android boot failed, error %d.\n", ret);
+               return CMD_RET_FAILURE;
+       }
+
+       /* Android standard slot names are 'a', 'b', ... */
+       slot[0] = BOOT_SLOT_NAME(ret);
+       slot[1] = '\0';
+       env_set(argv[1], slot);
+       printf("ANDROID: Booting slot: %s\n", slot);
+       return CMD_RET_SUCCESS;
+}
+
+U_BOOT_CMD(ab_select, 4, 0, do_ab_select,
+          "Select the slot used to boot from and register the boot attempt.",
+          "<slot_var_name> <interface> <dev[:part|#part_name]>\n"
+          "    - Load the slot metadata from the partition 'part' on\n"
+          "      device type 'interface' instance 'dev' and store the active\n"
+          "      slot in the 'slot_var_name' variable. This also updates the\n"
+          "      Android slot metadata with a boot attempt, which can cause\n"
+          "      successive calls to this function to return a different result\n"
+          "      if the returned slot runs out of boot attempts.\n"
+          "    - If 'part_name' is passed, preceded with a # instead of :, the\n"
+          "      partition name whose label is 'part_name' will be looked up in\n"
+          "      the partition table. This is commonly the \"misc\" partition.\n"
+);