From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?UTF-8?Q?Sean_Nyekj=c3=a6r?= <sean.nyekjaer@prevas.dk>
Date: Mon, 16 Jul 2018 08:05:25 +0200
Subject: [U-Boot] [RFC] cmd: add bootslot command to select/boot slot
 based on boot counts
In-Reply-To: <20180713123413.4115-1-martin@geanix.com>
References: <20180713123413.4115-1-martin@geanix.com>
Message-ID: <89febb3a-429e-6066-0791-cd6559e31b41@prevas.dk>
List-Id: <u-boot.lists.denx.de>
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To: u-boot@lists.denx.de

Hi,

On 2018-07-13 14:34, Martin Hundebøll wrote:
> The existing bootcount feature is targeted systems with a primary, and a
> rescue boot setup, where the number of boot tries to the primary boot is
> tracked. If the number exceeds the limit, the alternative/rescue is
> booted.
> 
> This patch adds support for a more sophisticated setup, where more than
> two boot slots can exist, and the order of slots can be configured.
> 
> The 'bootcommand' command reads the configured slots (and their
> priority/order) from a configured environment variable ("bootslots" by
> default). For each conifgured slot, a remaining boot count is maintained
> in an evnironment variable ("bootcount_<slot>" by default). If the first
> boot slot has positive boot count, it is booted using the slot specific
> boot command ("bootcmd_<slot>" by default). Otherwise the next slot is
> checked.
> 
> An example environment when using the bootslot command with two slots
> ("a" and "b"):
With RAUC bootslot's is specified with uppercase letters, uppercase is 
not preserved.
We end up with BOOT_b_LEFT=2...
botocmd_* is with lowercase, just to make things easier.

/Sean

> 
> bootslots=a b
> bootcount_a=3
> bootcount_b=3
> bootcmd_a=setenv bootargs $bootargs root=/dev/mmcblk0p1; booti $loadaddr
> bootcmd_b=setenv bootargs $bootargs root=/dev/mmcblk0p2; booti $loadaddr
> 
> Once linux is booted, it resets the bootcount variable for the booted
> slot using "fw_setenv":
> 
>> fw_setenv bootcount_a 3
> 
> When the non-booted slot is updated, the order is updated by setting the
> bootslots variable with "fw_setenv":
> 
>> fw_setenv bootslots=b a
> 
> Signed-off-by: Martin Hundebøll <martin@geanix.com>
Tested-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
> ---
>   cmd/Kconfig    |  42 +++++++++
>   cmd/Makefile   |   1 +
>   cmd/bootslot.c | 225 +++++++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 268 insertions(+)
>   create mode 100644 cmd/bootslot.c
> 
> diff --git a/cmd/Kconfig b/cmd/Kconfig
> index aec209006d..3919606e74 100644
> --- a/cmd/Kconfig
> +++ b/cmd/Kconfig
> @@ -1277,6 +1277,48 @@ config CMD_BOOTCOUNT
>   	  Enable the bootcount command, which allows interrogation and
>   	  reset of the bootcounter.
>   
> +config CMD_BOOTSLOT
> +	bool "Enable support for multiple boot slots"
> +	help
> +	  Parses an ordered list of configured boot slot names (e.g. "a b")
> +	  and selects a corresponding boot command based on the current
> +	  boot counter for each slot.
> +
> +config CMD_BOOTSLOT_ENV_SLOTS
> +	string "Environment variable to read bootslots from"
> +	depends on CMD_BOOTSLOT
> +	default "bootslots"
> +	help
> +	  Configures the environment variable to read out when looking for a
> +	  list of available boot sloots.
> +
> +config CMD_BOOTSLOT_ENV_COUNT
> +	string "Environment variable format string to read/write slot boot count from/to"
> +	depends on CMD_BOOTSLOT
> +	default "bootcount_%s"
> +	help
> +	  Configures the prefix to use when reading the boot count for a
> +	  specific slot. The prefix is concatenated with the slot name, so
> +	  that the boot count for slot "a" is read and saved to "<prefix>a".
> +
> +config CMD_BOOTSLOT_ENV_CMD
> +	string "Environment variable format string to read slot boot command from"
> +	depends on CMD_BOOTSLOT
> +	default "bootcmd_%s"
> +	help
> +	  Configures the prefix to use when reading the boot command for
> +	  specific slot. The prefix is concatenated with the slot name, so
> +	  that the boot command for slot "a" is read from "<prefix>a".
> +
> +config CMD_BOOTSLOT_DEFAULT_COUNT
> +	int "Default boot count for each configured slot"
> +	depends on CMD_BOOTSLOT
> +	default 3
> +	help
> +	  The default number of times a slot is tried before proceeding to the
> +	  slot. The default is used when a slot has no count yet, or when it
> +	  is reset with the "bootslot reset" command.
> +
>   config CMD_BSP
>   	bool "Enable board-specific commands"
>   	help
> diff --git a/cmd/Makefile b/cmd/Makefile
> index 323f1fd2c7..68c8e50c91 100644
> --- a/cmd/Makefile
> +++ b/cmd/Makefile
> @@ -26,6 +26,7 @@ obj-$(CONFIG_CMD_BOOTCOUNT) += bootcount.o
>   obj-$(CONFIG_CMD_BOOTEFI) += bootefi.o
>   obj-$(CONFIG_CMD_BOOTMENU) += bootmenu.o
>   obj-$(CONFIG_CMD_BOOTSTAGE) += bootstage.o
> +obj-$(CONFIG_CMD_BOOTSLOT) += bootslot.o
>   obj-$(CONFIG_CMD_BOOTZ) += bootz.o
>   obj-$(CONFIG_CMD_BOOTI) += booti.o
>   obj-$(CONFIG_CMD_BTRFS) += btrfs.o
> diff --git a/cmd/bootslot.c b/cmd/bootslot.c
> new file mode 100644
> index 0000000000..03897b1f60
> --- /dev/null
> +++ b/cmd/bootslot.c
> @@ -0,0 +1,225 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2018, Geanix, All rights reserved.
> + */
> +
> +#include <common.h>
> +#include <environment.h>
> +#include <stdlib.h>
> +#include <linux/kernel.h>
> +#include <linux/string.h>
> +#include <linux/compat.h>
> +#include <vsprintf.h>
> +
> +static char *bootslot_envname(const char *fmt, const char *slot)
> +{
> +	int len = strlen(fmt) + strlen(slot);
> +	char *envname = malloc(len + 1);
> +
> +	sprintf(envname, fmt, slot);
> +
> +	return envname;
> +}
> +
> +static unsigned long bootslot_get_count(const char *slot)
> +{
> +	char *envname;
> +	unsigned long count;
> +
> +	envname = bootslot_envname(CONFIG_CMD_BOOTSLOT_ENV_COUNT, slot);
> +	count = env_get_ulong(envname, 10, CONFIG_CMD_BOOTSLOT_DEFAULT_COUNT);
> +	free(envname);
> +
> +	return count;
> +}
> +
> +static void bootslot_set_count(const char *slot, unsigned long count)
> +{
> +	char *envname;
> +
> +	envname = bootslot_envname(CONFIG_CMD_BOOTSLOT_ENV_COUNT, slot);
> +	env_set_ulong(envname, count);
> +	free(envname);
> +}
> +
> +static const char *bootslot_get_cmd(const char *slot)
> +{
> +	char *envname;
> +	char *cmd;
> +
> +	envname = bootslot_envname(CONFIG_CMD_BOOTSLOT_ENV_CMD, slot);
> +	cmd = env_get(envname);
> +	free(envname);
> +
> +	return cmd;
> +}
> +
> +static char *bootslot_get_slots(int argc, char * const argv[])
> +{
> +	char *slots = NULL;
> +	int len = 1; /* make room for terminating \0 */
> +	int i;
> +
> +	/* read boot slots from environment if no args are given, or
> +	 * duplicate the argument if a single argument is given */
> +	if (argc == 1)
> +		return strdup(env_get(CONFIG_CMD_BOOTSLOT_ENV_SLOTS));
> +	else if (argc == 2)
> +		return strdup(argv[1]);
> +
> +	/* compute the string length of the list of slots */
> +	for (i = 1; i < argc; i++)
> +		len += strlen(argv[i]) + 1; /* add room for space separator */
> +
> +	/* allocate the string buffer and copy each slot argument to it */
> +	slots = kzalloc(len, 0);
> +	strcpy(slots, argv[1]);
> +
> +	for (i = 2; i < argc; i++) {
> +		strcat(slots, " ");
> +		strcat(slots, argv[i]);
> +	}
> +
> +	return slots;
> +}
> +
> +static int do_bootslot_list(cmd_tbl_t *cmdtp, int flag, int argc,
> +			    char * const argv[])
> +{
> +	char *mem = bootslot_get_slots(argc, argv);
> +	char *slots = mem;
> +	char *slot;
> +
> +	if (slots == NULL)
> +		return CMD_RET_USAGE;
> +
> +	printf("slot\tcount\tbootcmd\n");
> +	while ((slot = strsep(&slots, " ")) != NULL) {
> +		unsigned long count;
> +		const char *bootcmd;
> +
> +		if (strlen(slot) == 0)
> +			continue;
> +
> +		count = bootslot_get_count(slot);
> +		bootcmd = bootslot_get_cmd(slot);
> +
> +		if (bootcmd)
> +			printf("%s\t%lu\t%s\n", slot, count, bootcmd);
> +		else
> +			printf("%s\t%lu\t<not defined>\n", slot, count);
> +	}
> +
> +	free(mem);
> +
> +	return CMD_RET_SUCCESS;
> +}
> +
> +static int do_bootslot_reset(cmd_tbl_t *cmdtp, int flag, int argc,
> +			    char * const argv[])
> +{
> +	char *mem = bootslot_get_slots(argc, argv);
> +	char *slots = mem;
> +	char *slot;
> +
> +	if (slots == NULL)
> +		return CMD_RET_USAGE;
> +
> +	while ((slot = strsep(&slots, " ")) != NULL) {
> +		if (strlen(slot) == 0)
> +			continue;
> +		bootslot_set_count(slot, CONFIG_CMD_BOOTSLOT_DEFAULT_COUNT);
> +	}
> +
> +	free(mem);
> +
> +	return CMD_RET_SUCCESS;
> +}
> +
> +static int do_bootslot_boot(cmd_tbl_t *cmdtp, int flag, int argc,
> +			    char * const argv[])
> +{
> +	char *mem = bootslot_get_slots(argc, argv);
> +	char *slots = mem;
> +	char *slot;
> +	bool found_valid = false;
> +
> +	if (slots == NULL)
> +		return CMD_RET_USAGE;
> +
> +	while ((slot = strsep(&slots, " ")) != NULL) {
> +		const char *bootcmd;
> +		unsigned long count;
> +
> +		if (strlen(slot) == 0)
> +			continue;
> +
> +		count = bootslot_get_count(slot);
> +		if (count == 0) {
> +			printf("slot %s bootcount is zero; trying next...\n",
> +			       slot);
> +			continue;
> +		}
> +
> +		bootcmd = bootslot_get_cmd(slot);
> +		if (bootcmd == NULL) {
> +			printf("slot %s bootcmd not found; trying next...\n",
> +			       slot);
> +			continue;
> +		}
> +
> +		printf("slot %s has %lu boot tries remaining; booting...\n",
> +		       slot, count);
> +		found_valid = true;
> +		bootslot_set_count(slot, --count);
> +		env_save();
> +		run_command_list(bootcmd, -1, CMD_FLAG_ENV);
> +		break;
> +	}
> +
> +	free(mem);
> +
> +	if (found_valid == false) {
> +		printf("no valid bootslot found; resetting counters\n");
> +		run_command("bootslot reset", 0);
> +		return CMD_RET_FAILURE;
> +	}
> +
> +	return CMD_RET_SUCCESS;
> +}
> +
> +static cmd_tbl_t cmd_bootslot_sub[] = {
> +	U_BOOT_CMD_MKENT(boot, INT_MAX, 0, do_bootslot_boot, "", ""),
> +	U_BOOT_CMD_MKENT(list, INT_MAX, 1, do_bootslot_list, "", ""),
> +	U_BOOT_CMD_MKENT(reset, INT_MAX, 1, do_bootslot_reset, "", ""),
> +};
> +
> +/*
> + * Process a bootslots sub-command
> + */
> +static int do_bootslot(cmd_tbl_t *cmdtp, int flag, int argc,
> +		       char * const argv[])
> +{
> +	cmd_tbl_t *c;
> +
> +	/* Strip off leading 'bootslot' command argument */
> +	argc--;
> +	argv++;
> +
> +	c = find_cmd_tbl(argv[0], cmd_bootslot_sub,
> +			 ARRAY_SIZE(cmd_bootslot_sub));
> +
> +	if (c)
> +		return c->cmd(cmdtp, flag, argc, argv);
> +	else
> +		return CMD_RET_USAGE;
> +}
> +
> +
> +U_BOOT_CMD(bootslot, INT_MAX, 1, do_bootslot,
> +	"Bootslot command",
> +	" - select and boot slot based on counters\n"
> +	"boot [<slot>]          - Boot the passed or first valid slot in $bootslots\n"
> +	"list [<slot>]          - List remaining boot tries for passed or all slots in $bootslots\n"
> +	"reset [<slot>]         - Reset remaining boot tries for all or passed slot\n"
> +);
>