It is often desirable to configure the spl-boot-order (i.e. the order
that SPL probes devices to find the FIT image containing a full U-Boot)
such that it contains 'the same device the SPL stage was booted from'
early on. To support this, we introduce the 'same-as-spl' specifier
for the spl-boot-order property.
This commit adds:
- documentation for the new board_spl_was_booted_from() function that
individual SoCs/boards should provide, if they can determine where
the SPL was booted from
- implements the new board_spl_was_booted_from() stub function
- adds support for handling the 'same-as-spl' specifier and calling
into the per-SoC/per-board support code.
This also updates the documentation for the 'u-boot,spl-boot-order'
property.
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
+/**
+ * board_spl_was_booted_from() - retrieves the of-path the SPL was loaded from
+ *
+ * To support a 'same-as-spl' specification in the search-order for the next
+ * stage, we need a SoC- or board-specific way to handshake with what 'came
+ * before us' (either a BROM or TPL stage) and map the info retrieved onto
+ * a OF path.
+ *
+ * Returns
+ * NULL, on failure or if the device could not be identified
+ * a of_path (a string), on success
+ */
+__weak const char *board_spl_was_booted_from(void)
+{
+ debug("%s: no support for 'same-as-spl' for this board\n", __func__);
+ return NULL;
+}
+
void board_boot_order(u32 *spl_boot_list)
{
const void *blob = gd->fdt_blob;
void board_boot_order(u32 *spl_boot_list)
{
const void *blob = gd->fdt_blob;
(conf = fdt_stringlist_get(blob, chosen_node,
"u-boot,spl-boot-order", elem, NULL));
elem++) {
(conf = fdt_stringlist_get(blob, chosen_node,
"u-boot,spl-boot-order", elem, NULL));
elem++) {
+ const char *alias;
+
+ /* Handle the case of 'same device the SPL was loaded from' */
+ if (strncmp(conf, "same-as-spl", 11) == 0) {
+ conf = board_spl_was_booted_from();
+ if (!conf)
+ continue;
+ }
+
/* First check if the list element is an alias */
/* First check if the list element is an alias */
- const char *alias = fdt_get_alias(blob, conf);
+ alias = fdt_get_alias(blob, conf);
in the order they are listed: references (i.e. implicit paths), a full
path or an alias is expected for each entry.
in the order they are listed: references (i.e. implicit paths), a full
path or an alias is expected for each entry.
+A special specifier "same-as-spl" can be used at any position in the
+boot-order to direct U-Boot to insert the device the SPL was booted
+from there. Whether this is indeed inserted or silently ignored (if
+it is not supported on any given SoC/board or if the boot-device is
+not available to continue booting from) is implementation-defined.
+Note that if "same-as-spl" expands to an actual node for a given
+board, the corresponding node may appear multiple times in the
+boot-order (as there currently exists no mechanism to suppress
+duplicates from the list).
+
Example
-------
/ {
chosen {
Example
-------
/ {
chosen {
- u-boot,spl-boot-order = &sdmmc, "/sdhci@fe330000";
+ u-boot,spl-boot-order = "same-as-spl", &sdmmc, "/sdhci@fe330000";