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bootstd: Add the concept of a bootflow

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A bootflow encapsulates the process used to boot an operating system.
It typically has a control file (such as extlinux.conf) and information
about which 'bootdev' it came from.

Add the header file for this first, since it is needed by all other
files.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2022-04-24 23:31:05 -06:00 committed by Tom Rini
parent c24e58f599
commit 9d260253e8
2 changed files with 265 additions and 0 deletions
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5
MAINTAINERS
View File

@ -693,6 +693,11 @@ M: Simon Glass <sjg@chromium.org>
S: Maintained
F: tools/binman/
BOOTDEVICE
M: Simon Glass <sjg@chromium.org>
S: Maintained
F: include/bootflow.h
BTRFS
M: Marek Behun <marek.behun@nic.cz>
R: Qu Wenruo <wqu@suse.com>

260
include/bootflow.h Normal file
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@ -0,0 +1,260 @@
/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Copyright 2021 Google LLC
* Written by Simon Glass <sjg@chromium.org>
*/
#ifndef __bootflow_h
#define __bootflow_h
#include <linux/list.h>
/**
* enum bootflow_state_t - states that a particular bootflow can be in
*
* Only bootflows in state BOOTFLOWST_READY can be used to boot.
*
* See bootflow_state[] for the names for each of these
*/
enum bootflow_state_t {
BOOTFLOWST_BASE, /**< Nothing known yet */
BOOTFLOWST_MEDIA, /**< Media exists */
BOOTFLOWST_PART, /**< Partition exists */
BOOTFLOWST_FS, /**< Filesystem exists */
BOOTFLOWST_FILE, /**< Bootflow file exists */
BOOTFLOWST_READY, /**< Bootflow file loaded */
BOOTFLOWST_COUNT
};
/**
* struct bootflow - information about a bootflow
*
* This is connected into two separate linked lists:
*
* bm_sibling - links all bootflows in the same bootdev
* glob_sibling - links all bootflows in all bootdevs
*
* @bm_node: Points to siblings in the same bootdev
* @glob_node: Points to siblings in the global list (all bootdev)
* @dev: Bootdevice device which produced this bootflow
* @blk: Block device which contains this bootflow, NULL if this is a network
* device
* @part: Partition number (0 for whole device)
* @fs_type: Filesystem type (FS_TYPE...) if this is fixed by the media, else 0.
* For example, the sandbox host-filesystem bootdev sets this to
* FS_TYPE_SANDBOX
* @method: Bootmethod device used to perform the boot and read files
* @name: Name of bootflow (allocated)
* @state: Current state (enum bootflow_state_t)
* @subdir: Subdirectory to fetch files from (with trailing /), or NULL if none
* @fname: Filename of bootflow file (allocated)
* @buf: Bootflow file contents (allocated)
* @size: Size of bootflow file in bytes
* @err: Error number received (0 if OK)
*/
struct bootflow {
struct list_head bm_node;
struct list_head glob_node;
struct udevice *dev;
struct udevice *blk;
int part;
int fs_type;
struct udevice *method;
char *name;
enum bootflow_state_t state;
char *subdir;
char *fname;
char *buf;
int size;
int err;
};
/**
* enum bootflow_flags_t - flags for the bootflow iterator
*
* @BOOTFLOWF_FIXED: Only used fixed/internal media
* @BOOTFLOWF_SHOW: Show each bootdev before scanning it
* @BOOTFLOWF_ALL: Return bootflows with errors as well
* @BOOTFLOWF_SINGLE_DEV: Just scan one bootmeth
*/
enum bootflow_flags_t {
BOOTFLOWF_FIXED = 1 << 0,
BOOTFLOWF_SHOW = 1 << 1,
BOOTFLOWF_ALL = 1 << 2,
BOOTFLOWF_SINGLE_DEV = 1 << 3,
};
/**
* struct bootflow_iter - state for iterating through bootflows
*
* This starts at with the first bootdev/partition/bootmeth and can be used to
* iterate through all of them.
*
* Iteration starts with the bootdev. The first partition (0, i.e. whole device)
* is scanned first. For partition 0, it iterates through all the available
* bootmeths to see which one(s) can provide a bootflow. Then it moves to
* parition 1 (if there is one) and the process continues. Once all partitions
* are examined, it moves to the next bootdev.
*
* Initially @max_part is 0, meaning that only the whole device (@part=0) can be
* used. During scanning, if a partition table is found, then @max_part is
* updated to a larger value, no less than the number of available partitions.
* This ensures that iteration works through all partitions on the bootdev.
*
* @flags: Flags to use (see enum bootflow_flags_t)
* @dev: Current bootdev
* @part: Current partition number (0 for whole device)
* @method: Current bootmeth
* @max_part: Maximum hardware partition number in @dev, 0 if there is no
* partition table
* @err: Error obtained from checking the last iteration. This is used to skip
* forward (e.g. to skip the current partition because it is not valid)
* -ESHUTDOWN: try next bootdev
* @num_devs: Number of bootdevs in @dev_order
* @cur_dev: Current bootdev number, an index into @dev_order[]
* @dev_order: List of bootdevs to scan, in order of priority. The scan starts
* with the first one on the list
* @num_methods: Number of bootmeth devices in @method_order
* @cur_method: Current method number, an index into @method_order
* @method_order: List of bootmeth devices to use, in order
*/
struct bootflow_iter {
int flags;
struct udevice *dev;
int part;
struct udevice *method;
int max_part;
int err;
int num_devs;
int cur_dev;
struct udevice **dev_order;
int num_methods;
int cur_method;
struct udevice **method_order;
};
/**
* bootflow_iter_init() - Reset a bootflow iterator
*
* This sets everything to the starting point, ready for use.
*
* @iter: Place to store private info (inited by this call)
* @flags: Flags to use (see enum bootflow_flags_t)
*/
void bootflow_iter_init(struct bootflow_iter *iter, int flags);
/**
* bootflow_iter_uninit() - Free memory used by an interator
*
* @iter: Iterator to free
*/
void bootflow_iter_uninit(struct bootflow_iter *iter);
/**
* bootflow_scan_bootdev() - find the first bootflow in a bootdev
*
* If @flags includes BOOTFLOWF_ALL then bootflows with errors are returned too
*
* @dev: Boot device to scan, NULL to work through all of them until it
* finds one that * can supply a bootflow
* @iter: Place to store private info (inited by this call)
* @flags: Flags for bootdev (enum bootflow_flags_t)
* @bflow: Place to put the bootflow if found
* Return: 0 if found, -ENODEV if no device, other -ve on other error
* (iteration can continue)
*/
int bootflow_scan_bootdev(struct udevice *dev, struct bootflow_iter *iter,
int flags, struct bootflow *bflow);
/**
* bootflow_scan_first() - find the first bootflow
*
* This works through the available bootdev devices until it finds one that
* can supply a bootflow. It then returns that
*
* If @flags includes BOOTFLOWF_ALL then bootflows with errors are returned too
*
* @iter: Place to store private info (inited by this call), with
* @flags: Flags for bootdev (enum bootflow_flags_t)
* @bflow: Place to put the bootflow if found
* Return: 0 if found, -ENODEV if no device, other -ve on other error (iteration
* can continue)
*/
int bootflow_scan_first(struct bootflow_iter *iter, int flags,
struct bootflow *bflow);
/**
* bootflow_scan_next() - find the next bootflow
*
* This works through the available bootdev devices until it finds one that
* can supply a bootflow. It then returns that bootflow
*
* @iter: Private info (as set up by bootflow_scan_first())
* @bflow: Place to put the bootflow if found
* Return: 0 if found, -ENODEV if no device, -ESHUTDOWN if no more bootflows,
* other -ve on other error (iteration can continue)
*/
int bootflow_scan_next(struct bootflow_iter *iter, struct bootflow *bflow);
/**
* bootflow_first_glob() - Get the first bootflow from the global list
*
* Returns the first bootflow in the global list, no matter what bootflow it is
* attached to
*
* @bflowp: Returns a pointer to the bootflow
* Return: 0 if found, -ENOENT if there are no bootflows
*/
int bootflow_first_glob(struct bootflow **bflowp);
/**
* bootflow_next_glob() - Get the next bootflow from the global list
*
* Returns the next bootflow in the global list, no matter what bootflow it is
* attached to
*
* @bflowp: On entry, the last bootflow returned , e.g. from
* bootflow_first_glob()
* Return: 0 if found, -ENOENT if there are no more bootflows
*/
int bootflow_next_glob(struct bootflow **bflowp);
/**
* bootflow_free() - Free memory used by a bootflow
*
* This frees fields within @bflow, but not the @bflow pointer itself
*/
void bootflow_free(struct bootflow *bflow);
/**
* bootflow_boot() - boot a bootflow
*
* @bflow: Bootflow to boot
* Return: -EPROTO if bootflow has not been loaded, -ENOSYS if the bootflow
* type is not supported, -EFAULT if the boot returned without an error
* when we are expecting it to boot, -ENOTSUPP if trying method resulted in
* finding out that is not actually supported for this boot and should not
* be tried again unless something changes
*/
int bootflow_boot(struct bootflow *bflow);
/**
* bootflow_run_boot() - Try to boot a bootflow
*
* @iter: Current iteration (or NULL if none). Used to disable a bootmeth if the
* boot returns -ENOTSUPP
* @bflow: Bootflow to boot
* Return: result of trying to boot
*/
int bootflow_run_boot(struct bootflow_iter *iter, struct bootflow *bflow);
/**
* bootflow_state_get_name() - Get the name of a bootflow state
*
* @state: State to check
* Return: name, or "?" if invalid
*/
const char *bootflow_state_get_name(enum bootflow_state_t state);
#endif