22cdb3f0f1
It is is sometimes desired to be able to skip decrementing the number of tries remaining in an Android A/B boot, and instead just check which slot will be tried later. This can commonly be be the case for platforms that want to A/B u-boot itself, but are required to boot from a FAT MBR partition. In these cases, u-boot must do an early check that the MBR points to the correct A/B boot partition, and if not rewrite the MBR to point to the correct one and reboot. Decrementing the try count in this case is not desired because it means that each u-boot might constantly ping-pong overwriting the MBR and rebooting until all the retries are used up. Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
69 lines
2.1 KiB
C
69 lines
2.1 KiB
C
// SPDX-License-Identifier: BSD-2-Clause
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/*
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* Copyright (C) 2017 The Android Open Source Project
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*/
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#include <common.h>
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#include <android_ab.h>
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#include <command.h>
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#include <env.h>
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#include <part.h>
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static int do_ab_select(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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int ret;
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struct blk_desc *dev_desc;
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struct disk_partition part_info;
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char slot[2];
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bool dec_tries = true;
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if (argc < 4)
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return CMD_RET_USAGE;
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for (int i = 4; i < argc; i++) {
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if (strcmp(argv[i], "--no-dec") == 0) {
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dec_tries = false;
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} else {
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return CMD_RET_USAGE;
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}
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}
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/* Lookup the "misc" partition from argv[2] and argv[3] */
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if (part_get_info_by_dev_and_name_or_num(argv[2], argv[3],
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&dev_desc, &part_info,
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false) < 0) {
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return CMD_RET_FAILURE;
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}
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ret = ab_select_slot(dev_desc, &part_info, dec_tries);
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if (ret < 0) {
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printf("Android boot failed, error %d.\n", ret);
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return CMD_RET_FAILURE;
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}
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/* Android standard slot names are 'a', 'b', ... */
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slot[0] = BOOT_SLOT_NAME(ret);
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slot[1] = '\0';
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env_set(argv[1], slot);
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printf("ANDROID: Booting slot: %s\n", slot);
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return CMD_RET_SUCCESS;
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}
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U_BOOT_CMD(ab_select, 5, 0, do_ab_select,
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"Select the slot used to boot from and register the boot attempt.",
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"<slot_var_name> <interface> <dev[:part|#part_name]> [--no-dec]\n"
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" - Load the slot metadata from the partition 'part' on\n"
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" device type 'interface' instance 'dev' and store the active\n"
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" slot in the 'slot_var_name' variable. This also updates the\n"
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" Android slot metadata with a boot attempt, which can cause\n"
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" successive calls to this function to return a different result\n"
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" if the returned slot runs out of boot attempts.\n"
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" - If 'part_name' is passed, preceded with a # instead of :, the\n"
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" partition name whose label is 'part_name' will be looked up in\n"
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" the partition table. This is commonly the \"misc\" partition.\n"
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" - If '--no-dec' is set, the number of tries remaining will not\n"
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" decremented for the selected boot slot\n"
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);
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