From: Quentin Schulz <quentin.sch...@cherry.de> U-Boot typically can be loaded from different storage media, such as eMMC, SD card, SPI flash, but also from non-persistent media such as USB (via proprietary protocols loading directly into SRAM, or fastboot, DFU, etc..), JTAG, ...
This information is usually reported by the BootROM via some proprietary mechanism (some specific address in registers/DRAM for example). For Rockchip, that information is stored in a register (BROM_BOOTSOURCE_ID_ADDR). While we already have the information about which medium was used to load U-Boot proper from SPL (via /chosen/u-boot,spl-boot-device), this new property represents the medium used to load U-Boot first phase (depending on configuration, can be VPL/TPL/SPL) which absolutely may differ from the one used to load U-Boot proper! It would be useful to know which medium was used to load the first phase of U-Boot, for example to check fallback mechanisms (proper loaded from a different medium than first phase) are actually working. For now, this only applies to Rockchip's U-Boot proper DT but could be applied to the kernel's as well and possibly for other architectures or vendors. Signed-off-by: Quentin Schulz <quentin.sch...@cherry.de> --- I have a board (RK3399 Puma) running U-Boot which currently has 9 boot scenarios (eMMC/SD/SPI-NOR for the first phase, eMMC/SD/SPI-NOR for the next phases; not counting USB loading yet, which would make it a few more). I cannot force the BootROM of this board to select a specific device aside from erasing the other media. The only way to identify which device was used for the first phase is to parse U-Boot first phase console output or add some custom logic for my board. To validate that a new version of the bootloader works, including the fallback mechanisms, I need to make sure the BootROM loads the first phase from the expected device otherwise I may have false positives. This would be useful for automated testing. Patches pending in the devicetree-spec[1] and dt-schema[2], hence the RFC here. [1] https://lore.kernel.org/devicetree-spec/20250505-bootsource-v2-1-5a315d9bf...@cherry.de/ [2] https://github.com/devicetree-org/dt-schema/pull/169 --- arch/arm/mach-rockchip/spl-boot-order.c | 34 ++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) diff --git a/arch/arm/mach-rockchip/spl-boot-order.c b/arch/arm/mach-rockchip/spl-boot-order.c index 3dce9b30898d49a86ec1963846ffdddea521e201..1bfd120adc46d4c847fc81112033bcf193be96d3 100644 --- a/arch/arm/mach-rockchip/spl-boot-order.c +++ b/arch/arm/mach-rockchip/spl-boot-order.c @@ -242,30 +242,38 @@ int spl_decode_boot_device(u32 boot_device, char *buf, size_t buflen) void spl_perform_fixups(struct spl_image_info *spl_image) { + const char *bootrom_ofpath = board_spl_was_booted_from(); void *blob = spl_image_fdt_addr(spl_image); char boot_ofpath[512]; int chosen, ret; - /* - * Inject the ofpath of the device the full U-Boot (or Linux in - * Falcon-mode) was booted from into the FDT, if a FDT has been - * loaded at the same time. - */ if (!blob) return; - ret = spl_decode_boot_device(spl_image->boot_device, boot_ofpath, sizeof(boot_ofpath)); - if (ret) { - pr_err("%s: could not map boot_device to ofpath: %d\n", __func__, ret); - return; - } - chosen = fdt_find_or_add_subnode(blob, 0, "chosen"); if (chosen < 0) { pr_err("%s: could not find/create '/chosen'\n", __func__); return; } - fdt_setprop_string(blob, chosen, - "u-boot,spl-boot-device", boot_ofpath); + + /* + * Inject the ofpath of the device the full U-Boot (or Linux in + * Falcon-mode) was booted from into the FDT. + */ + ret = spl_decode_boot_device(spl_image->boot_device, boot_ofpath, sizeof(boot_ofpath)); + if (ret) + pr_err("%s: could not map boot_device to ofpath: %d\n", __func__, ret); + else + fdt_setprop_string(blob, chosen, + "u-boot,spl-boot-device", boot_ofpath); + + /* + * Inject the ofpath of the device the BootROM loaded the very first + * stage from into the FDT. + */ + if (!bootrom_ofpath) + pr_err("%s: could not map BootROM boot device to ofpath\n", __func__); + else + fdt_setprop_string(blob, chosen, "bootsource", bootrom_ofpath); } #endif --- base-commit: a8f20bb6650df56d2600cda2c66f9349df9e49c8 change-id: 20250730-dt-chosen-bootsource-f3c8ddde2001 Best regards, -- Quentin Schulz <quentin.sch...@cherry.de>
