[RFC PATCH 10/20] cmd: bootm: accept storage device as image source
Daniel Golle
daniel at makrotopia.org
Mon Feb 16 22:22:51 CET 2026
Extend the bootm command to accept a storage device type keyword as
the first argument:
bootm mmc <dev>:<part> - boot from MMC/SD/eMMC partition
bootm mtd <name> - boot from MTD partition
bootm ubi <volume> - boot from UBI volume
When a known device-type keyword is found, an image_loader is
constructed using the corresponding backend and stored in
images.loader. The rest of the bootm flow proceeds unchanged:
boot_get_kernel() uses image_loader_map() for format detection and
FDT structure loading, then fit_image_load() uses the on-demand
storage path for sub-image data.
If the first argument does not match a device-type keyword (i.e. it
looks like a hex address, or is absent), images.loader remains NULL
and the existing in-memory path is taken -- full backward compatibility.
The #config suffix follows the same convention as existing bootm FIT
config selection. Multiple # suffixes can be chained to select a
base config and one or more device-tree overlays:
bootm mmc 0:4#config-1#overlay-wifi#overlay-lcd
bootm mtd firmware#config-1
Gated by CONFIG_BOOTM_STORAGE.
Signed-off-by: Daniel Golle <daniel at makrotopia.org>
---
boot/Kconfig | 13 +++++
boot/bootm.c | 62 +++++++++++++++++---
cmd/bootm.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++--
include/bootm.h | 2 +
4 files changed, 212 insertions(+), 13 deletions(-)
diff --git a/boot/Kconfig b/boot/Kconfig
index 89832014af6..1f870c7d251 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -1211,6 +1211,19 @@ config IMAGE_LOADER_UBI
framework. Auto-attaches the UBI device from the device tree
if not already attached.
+config BOOTM_STORAGE
+ bool "Allow bootm to load images directly from storage"
+ depends on CMDLINE && FIT && IMAGE_LOADER
+ help
+ Extends the bootm command to accept "mmc <dev>:<part>",
+ "mtd <name>", or "ubi <volume>" as the image source instead
+ of a RAM address. Sub-images (kernel, FDT, ramdisk, etc.)
+ are loaded from storage on demand; filesystem sub-images are
+ never read.
+
+ Requires at least one IMAGE_LOADER backend to be enabled
+ (IMAGE_LOADER_BLK, IMAGE_LOADER_MTD, or IMAGE_LOADER_UBI).
+
config DISTRO_DEFAULTS
bool "(deprecated) Script-based booting of Linux distributions"
select CMDLINE
diff --git a/boot/bootm.c b/boot/bootm.c
index 4bdca22ea8c..67d161f6e3a 100644
--- a/boot/bootm.c
+++ b/boot/bootm.c
@@ -13,6 +13,7 @@
#include <env.h>
#include <errno.h>
#include <fdt_support.h>
+#include <image-loader.h>
#include <irq_func.h>
#include <lmb.h>
#include <log.h>
@@ -146,7 +147,22 @@ static int boot_get_kernel(const char *addr_fit, struct bootm_headers *images,
/* check image type, for FIT images get FIT kernel node */
*os_data = *os_len = 0;
- buf = map_sysmem(img_addr, 0);
+ if (IS_ENABLED(CONFIG_BOOTM_STORAGE) && images->loader) {
+ /*
+ * Storage path: read enough bytes to detect the image
+ * format. genimg_get_kernel_addr_fit() above still
+ * parsed any #config / :subimage suffix so the FIT
+ * selection variables are populated.
+ */
+ buf = image_loader_map(images->loader, 0, 64);
+ if (!buf) {
+ puts("Cannot read image header from storage\n");
+ return -EIO;
+ }
+ img_addr = map_to_sysmem(buf);
+ } else {
+ buf = map_sysmem(img_addr, 0);
+ }
switch (genimg_get_format(buf)) {
#if CONFIG_IS_ENABLED(LEGACY_IMAGE_FORMAT)
case IMAGE_FORMAT_LEGACY:
@@ -192,6 +208,20 @@ static int boot_get_kernel(const char *addr_fit, struct bootm_headers *images,
#endif
#if CONFIG_IS_ENABLED(FIT)
case IMAGE_FORMAT_FIT:
+ if (IS_ENABLED(CONFIG_BOOTM_STORAGE) && images->loader) {
+ /*
+ * Extend the mapping to cover the full FIT
+ * FDT structure so all metadata is accessible.
+ */
+ size_t fdt_sz = fdt_totalsize(buf);
+
+ buf = image_loader_map(images->loader, 0, fdt_sz);
+ if (!buf) {
+ puts("Cannot read FIT header from storage\n");
+ return -ENOMEM;
+ }
+ img_addr = map_to_sysmem(buf);
+ }
os_noffset = fit_image_load(images, img_addr,
&fit_uname_kernel, &fit_uname_config,
IH_ARCH_DEFAULT, IH_TYPE_KERNEL,
@@ -991,11 +1021,21 @@ int bootm_run_states(struct bootm_info *bmi, int states)
* Work through the states and see how far we get. We stop on
* any error.
*/
- if (states & BOOTM_STATE_START)
+ if (states & BOOTM_STATE_START) {
ret = bootm_start();
+ /*
+ * bootm_start() zeroes the global images struct. Restore
+ * the loader pointer so the storage-backed path works.
+ */
+ if (IS_ENABLED(CONFIG_BOOTM_STORAGE) && bmi->loader)
+ images->loader = bmi->loader;
+ }
- if (!ret && (states & BOOTM_STATE_PRE_LOAD))
- ret = bootm_pre_load(bmi->addr_img);
+ if (!ret && (states & BOOTM_STATE_PRE_LOAD)) {
+ /* Pre-load verification is not applicable to storage boot */
+ if (!IS_ENABLED(CONFIG_BOOTM_STORAGE) || !images->loader)
+ ret = bootm_pre_load(bmi->addr_img);
+ }
if (!ret && (states & BOOTM_STATE_FINDOS))
ret = bootm_find_os(bmi->cmd_name, bmi->addr_img);
@@ -1003,8 +1043,11 @@ int bootm_run_states(struct bootm_info *bmi, int states)
if (!ret && (states & BOOTM_STATE_FINDOTHER)) {
ulong img_addr;
- img_addr = bmi->addr_img ? hextoul(bmi->addr_img, NULL)
- : image_load_addr;
+ if (IS_ENABLED(CONFIG_BOOTM_STORAGE) && images->loader)
+ img_addr = images->os.start;
+ else
+ img_addr = bmi->addr_img ? hextoul(bmi->addr_img, NULL)
+ : image_load_addr;
ret = bootm_find_other(img_addr, bmi->conf_ramdisk,
bmi->conf_fdt);
}
@@ -1097,8 +1140,13 @@ int bootm_run_states(struct bootm_info *bmi, int states)
}
/* Now run the OS! We hope this doesn't return */
- if (!ret && (states & BOOTM_STATE_OS_GO))
+ if (!ret && (states & BOOTM_STATE_OS_GO)) {
+ /* Release storage backend before jumping — no return expected */
+ if (IS_ENABLED(CONFIG_BOOTM_STORAGE) && images->loader)
+ image_loader_cleanup(images->loader);
+
ret = boot_selected_os(BOOTM_STATE_OS_GO, bmi, boot_fn);
+ }
/* Deal with any fallout */
err:
diff --git a/cmd/bootm.c b/cmd/bootm.c
index 2c5aea26d98..6c26dd8e36d 100644
--- a/cmd/bootm.c
+++ b/cmd/bootm.c
@@ -12,6 +12,7 @@
#include <env.h>
#include <errno.h>
#include <image.h>
+#include <image-loader.h>
#include <malloc.h>
#include <nand.h>
#include <asm/byteorder.h>
@@ -132,14 +133,123 @@ static int do_bootm_subcommand(struct cmd_tbl *cmdtp, int flag, int argc,
/* bootm - boot application image from image in memory */
/*******************************************************************/
+#if IS_ENABLED(CONFIG_BOOTM_STORAGE)
+/**
+ * bootm_init_loader() - Try to parse a storage device spec from argv
+ *
+ * If argv[0] is a known device-type keyword ("mmc", "mtd", "ubi"),
+ * initialise @ldr as the corresponding backend and return the number
+ * of argv entries consumed. The optional #config[#overlay...] suffix
+ * is stripped from the device spec and returned via @conf_name.
+ *
+ * @ldr: loader to initialise
+ * @argc: argument count (after removing the "bootm" verb)
+ * @argv: argument vector
+ * @conf_name: on output, points to the #config string (incl. '#') or NULL
+ * Return: number of argv entries consumed (>0), 0 if no storage keyword
+ * was found, or negative errno on init failure
+ */
+static int bootm_init_loader(struct image_loader *ldr,
+ int argc, char *const argv[],
+ const char **conf_name)
+{
+ const char *devtype;
+ char *devspec;
+ char *hash;
+ int ret;
+
+ if (argc < 2)
+ return 0;
+
+ devtype = argv[0];
+ devspec = (char *)argv[1];
+ *conf_name = NULL;
+
+ /* Locate the first '#' — its meaning depends on the backend */
+ hash = strchr(devspec, '#');
+
+ if (IS_ENABLED(CONFIG_IMAGE_LOADER_BLK) &&
+ !strcmp(devtype, "mmc")) {
+ /*
+ * Block device specs use '#' for partition names when no ':'
+ * precedes it (e.g. "0#kernel"). Only treat the first '#'
+ * as the FIT config separator when ':' appears before it
+ * (e.g. "0:4#config-1"), otherwise the first '#' is the
+ * partition name and a second '#' starts the config
+ * (e.g. "0#kernel#config-1").
+ */
+ char *colon = strchr(devspec, ':');
+
+ if (!(colon && hash && colon < hash) && hash)
+ hash = strchr(hash + 1, '#');
+ if (hash) {
+ *conf_name = hash;
+ *hash = '\0';
+ }
+ ret = image_loader_init_blk(ldr, "mmc", devspec);
+ if (hash)
+ *hash = '#';
+ } else if (IS_ENABLED(CONFIG_IMAGE_LOADER_MTD) &&
+ !strcmp(devtype, "mtd")) {
+ if (hash) {
+ *conf_name = hash;
+ *hash = '\0';
+ }
+ ret = image_loader_init_mtd(ldr, devspec);
+ if (hash)
+ *hash = '#';
+ } else if (IS_ENABLED(CONFIG_IMAGE_LOADER_UBI) &&
+ !strcmp(devtype, "ubi")) {
+ if (hash) {
+ *conf_name = hash;
+ *hash = '\0';
+ }
+ ret = image_loader_init_ubi(ldr, devspec);
+ if (hash)
+ *hash = '#';
+ } else {
+ return 0; /* not a storage keyword */
+ }
+
+ if (ret) {
+ printf("Failed to init %s loader: %d\n", devtype, ret);
+ return ret;
+ }
+
+ return 2; /* consumed: keyword + device-spec */
+}
+#endif
+
int do_bootm(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
{
struct bootm_info bmi;
int ret;
+#if IS_ENABLED(CONFIG_BOOTM_STORAGE)
+ struct image_loader ldr = {};
+ const char *conf_name = NULL;
+ int consumed = 0;
+#endif
/* determine if we have a sub command */
argc--; argv++;
+
+#if IS_ENABLED(CONFIG_BOOTM_STORAGE)
+ /* Try storage device spec before checking for hex/subcommand */
+ consumed = bootm_init_loader(&ldr, argc, argv, &conf_name);
+ if (consumed < 0)
+ return CMD_RET_FAILURE;
+ if (consumed > 0) {
+ ldr.alloc_ptr = image_load_addr;
+ argc -= consumed;
+ argv += consumed;
+ }
+#endif
+
+#if IS_ENABLED(CONFIG_BOOTM_STORAGE)
+ if (argc > 0 && !consumed) {
+#else
if (argc > 0) {
+#endif
char *endp;
hextoul(argv[0], &endp);
@@ -156,12 +266,25 @@ int do_bootm(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
}
bootm_init(&bmi);
- if (argc)
- bmi.addr_img = argv[0];
- if (argc > 1)
- bmi.conf_ramdisk = argv[1];
- if (argc > 2)
- bmi.conf_fdt = argv[2];
+#if IS_ENABLED(CONFIG_BOOTM_STORAGE)
+ if (consumed > 0) {
+ bmi.addr_img = conf_name; /* "#config-1" or NULL */
+ bmi.loader = &ldr;
+ if (argc > 0)
+ bmi.conf_ramdisk = argv[0];
+ if (argc > 1)
+ bmi.conf_fdt = argv[1];
+ } else {
+#else
+ {
+#endif
+ if (argc)
+ bmi.addr_img = argv[0];
+ if (argc > 1)
+ bmi.conf_ramdisk = argv[1];
+ if (argc > 2)
+ bmi.conf_fdt = argv[2];
+ }
/* set up argc and argv[] since some OSes use them */
bmi.argc = argc;
@@ -169,6 +292,11 @@ int do_bootm(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
ret = bootm_run(&bmi);
+#if IS_ENABLED(CONFIG_BOOTM_STORAGE)
+ if (ldr.read)
+ image_loader_cleanup(&ldr);
+#endif
+
return ret ? CMD_RET_FAILURE : 0;
}
@@ -204,6 +332,14 @@ U_BOOT_LONGHELP(bootm,
"\taddr#<conf_uname> - configuration specification\n"
"\tUse iminfo command to get the list of existing component\n"
"\timages and configurations.\n"
+#endif
+#if IS_ENABLED(CONFIG_BOOTM_STORAGE)
+ "\nAlternatively, boot directly from a storage device:\n"
+ "\tbootm mmc <dev>:<part>[#conf] - boot from MMC/SD partition\n"
+ "\tbootm mtd <name>[#conf] - boot from MTD partition\n"
+ "\tbootm ubi <volume>[#conf] - boot from UBI volume\n"
+ "\tThe #conf suffix selects a FIT configuration; additional\n"
+ "\t#overlay suffixes select device-tree overlays.\n"
#endif
"\nSub-commands to do part of the bootm sequence. The sub-commands "
"must be\n"
diff --git a/include/bootm.h b/include/bootm.h
index 4060cec7fc0..ebc014b3468 100644
--- a/include/bootm.h
+++ b/include/bootm.h
@@ -40,6 +40,7 @@ struct cmd_tbl;
* boot_get_fdt() for processing, or NULL for none
* @boot_progress: true to show boot progress
* @images: images information
+ * @loader: image loader for storage-backed boot (NULL for in-memory)
* @cmd_name: command which invoked this operation, e.g. "bootm"
* @argc: Number of arguments to the command (excluding the actual command).
* This is 0 if there are no arguments
@@ -51,6 +52,7 @@ struct bootm_info {
const char *conf_fdt;
bool boot_progress;
struct bootm_headers *images;
+ struct image_loader *loader;
const char *cmd_name;
int argc;
char *const *argv;
--
2.53.0
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