fdt: Add option to default to most compatible conf in a fit image

When booting a fit image with multiple configurations, the user either has to
specify which configuration to use explicitly, or there has to be a default
defined which is chosen automatically. This change adds an option to change
that behavior so that a configuration can be selected explicitly, or the
configuration which has the device tree that claims to be compatible with the
earliest item in U-Boot's device tree.

In other words, if U-Boot claimed to be compatible with A, B, and then C, and
the configurations claimed to be compatible with A, D and B, D and D, E, the
first configuration, A, D, would be chosen. Both the first and second
configurations match, but the first one matches a more specific entry in
U-Boot's device tree. The order in the kernel's device tree is ignored.

Signed-off-by: Gabe Black <gabeblack@google.com>

Commit-Ready: Gabe Black <gabeblack@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Gabe Black 2012-10-25 16:31:10 +00:00 committed by Gerald Van Baren
parent 67e1ea26e8
commit d95f6ec733
4 changed files with 150 additions and 0 deletions

11
README
View File

@ -2597,6 +2597,17 @@ FIT uImage format:
-150 common/cmd_nand.c Incorrect FIT image format
151 common/cmd_nand.c FIT image format OK
- FIT image support:
CONFIG_FIT
Enable support for the FIT uImage format.
CONFIG_FIT_BEST_MATCH
When no configuration is explicitly selected, default to the
one whose fdt's compatibility field best matches that of
U-Boot itself. A match is considered "best" if it matches the
most specific compatibility entry of U-Boot's fdt's root node.
The order of entries in the configuration's fdt is ignored.
- Standalone program support:
CONFIG_STANDALONE_LOAD_ADDR

View File

@ -949,8 +949,19 @@ static void *boot_get_kernel(cmd_tbl_t *cmdtp, int flag, int argc,
* node
*/
bootstage_mark(BOOTSTAGE_ID_FIT_NO_UNIT_NAME);
#ifdef CONFIG_FIT_BEST_MATCH
if (fit_uname_config)
cfg_noffset =
fit_conf_get_node(fit_hdr,
fit_uname_config);
else
cfg_noffset =
fit_conf_find_compat(fit_hdr,
gd->fdt_blob);
#else
cfg_noffset = fit_conf_get_node(fit_hdr,
fit_uname_config);
#endif
if (cfg_noffset < 0) {
bootstage_error(BOOTSTAGE_ID_FIT_NO_UNIT_NAME);
return NULL;

View File

@ -3049,6 +3049,133 @@ int fit_check_format(const void *fit)
return 1;
}
/**
* fit_conf_find_compat
* @fit: pointer to the FIT format image header
* @fdt: pointer to the device tree to compare against
*
* fit_conf_find_compat() attempts to find the configuration whose fdt is the
* most compatible with the passed in device tree.
*
* Example:
*
* / o image-tree
* |-o images
* | |-o fdt@1
* | |-o fdt@2
* |
* |-o configurations
* |-o config@1
* | |-fdt = fdt@1
* |
* |-o config@2
* |-fdt = fdt@2
*
* / o U-Boot fdt
* |-compatible = "foo,bar", "bim,bam"
*
* / o kernel fdt1
* |-compatible = "foo,bar",
*
* / o kernel fdt2
* |-compatible = "bim,bam", "baz,biz"
*
* Configuration 1 would be picked because the first string in U-Boot's
* compatible list, "foo,bar", matches a compatible string in the root of fdt1.
* "bim,bam" in fdt2 matches the second string which isn't as good as fdt1.
*
* returns:
* offset to the configuration to use if one was found
* -1 otherwise
*/
int fit_conf_find_compat(const void *fit, const void *fdt)
{
int ndepth = 0;
int noffset, confs_noffset, images_noffset;
const void *fdt_compat;
int fdt_compat_len;
int best_match_offset = 0;
int best_match_pos = 0;
confs_noffset = fdt_path_offset(fit, FIT_CONFS_PATH);
images_noffset = fdt_path_offset(fit, FIT_IMAGES_PATH);
if (confs_noffset < 0 || images_noffset < 0) {
debug("Can't find configurations or images nodes.\n");
return -1;
}
fdt_compat = fdt_getprop(fdt, 0, "compatible", &fdt_compat_len);
if (!fdt_compat) {
debug("Fdt for comparison has no \"compatible\" property.\n");
return -1;
}
/*
* Loop over the configurations in the FIT image.
*/
for (noffset = fdt_next_node(fit, confs_noffset, &ndepth);
(noffset >= 0) && (ndepth > 0);
noffset = fdt_next_node(fit, noffset, &ndepth)) {
const void *kfdt;
const char *kfdt_name;
int kfdt_noffset;
const char *cur_fdt_compat;
int len;
size_t size;
int i;
if (ndepth > 1)
continue;
kfdt_name = fdt_getprop(fit, noffset, "fdt", &len);
if (!kfdt_name) {
debug("No fdt property found.\n");
continue;
}
kfdt_noffset = fdt_subnode_offset(fit, images_noffset,
kfdt_name);
if (kfdt_noffset < 0) {
debug("No image node named \"%s\" found.\n",
kfdt_name);
continue;
}
/*
* Get a pointer to this configuration's fdt.
*/
if (fit_image_get_data(fit, kfdt_noffset, &kfdt, &size)) {
debug("Failed to get fdt \"%s\".\n", kfdt_name);
continue;
}
len = fdt_compat_len;
cur_fdt_compat = fdt_compat;
/*
* Look for a match for each U-Boot compatibility string in
* turn in this configuration's fdt.
*/
for (i = 0; len > 0 &&
(!best_match_offset || best_match_pos > i); i++) {
int cur_len = strlen(cur_fdt_compat) + 1;
if (!fdt_node_check_compatible(kfdt, 0,
cur_fdt_compat)) {
best_match_offset = noffset;
best_match_pos = i;
break;
}
len -= cur_len;
cur_fdt_compat += cur_len;
}
}
if (!best_match_offset) {
debug("No match found.\n");
return -1;
}
return best_match_offset;
}
/**
* fit_conf_get_node - get node offset for configuration of a given unit name
* @fit: pointer to the FIT format image header

View File

@ -615,6 +615,7 @@ int fit_image_check_type(const void *fit, int noffset, uint8_t type);
int fit_image_check_comp(const void *fit, int noffset, uint8_t comp);
int fit_check_format(const void *fit);
int fit_conf_find_compat(const void *fit, const void *fdt);
int fit_conf_get_node(const void *fit, const char *conf_uname);
int fit_conf_get_kernel_node(const void *fit, int noffset);
int fit_conf_get_ramdisk_node(const void *fit, int noffset);