This series adds support for running U-Boot in snagboot mode on Qualcomm Snapdragon platforms, targeting the Lemans-EVK board.
Snagboot is an open-source, scriptable flashing framework that provides an alternative to the proprietary Firehose protocol for device provisioning. Like the traditional EDL+Firehose flow, Snagboot uses the Qualcomm boot ROM recovery mode (EDL) and Sahara protocol to download and execute bootloaders. However, instead of using the proprietary Firehose programmer, Snagboot loads U-Boot into DDR and uses the standard fastboot protocol for device flashing. The framework consists of three modular components: snagrecover (downloads XBL/QCLib to initialize DDR and load U-Boot into RAM), snagflash (communicates with U-Boot over USB using fastboot to flash system images), and snagfactory (orchestrates parallel factory flashing tasks). In the snagboot execution flow, ROM code in recovery mode loads snagrecover, which downloads XBL to internal memory. XBL executes and initializes DDR, then snagrecover downloads U-Boot into DDR and transfers control to it. At this point, XBL has left the MMU enabled with its own page tables and has not initialized PSCI firmware or populated the Command DB. U-Boot must handle this non-standard boot environment to enter fastboot mode for device flashing. This series addresses the specific requirements of the snagboot flow: Patch 1 changes SYSRESET_PSCI from 'select' to 'imply' so it can be disabled on platforms where PSCI firmware is unavailable. Patch 2 guards show_psci_version() and qcom_psci_fixup() with CONFIG_ARM_SMCCC to prevent build failures when SMCCC is disabled. Patch 3 adds CONFIG_QCOM_SNAGBOOT_SUPPORT option to enable snagboot mode support on Qualcomm platforms. Patch 4 disables the MMU and invalidates TLBs at the earliest entry point to clear stale page tables left by previous bootloader before U-Boot sets up its own MMU. Patch 5 adds QCOM_COMMAND_DB_OPTIONAL to allow the CMD DB driver to bind successfully when CMD DB data is not populated by XBL, logging a warning instead of failing. Patch 6 adds qcom_lemans_snagboot_defconfig for Lemans-EVK, based on qcom_defconfig with snagboot-specific settings. Signed-off-by: Balaji Selvanathan <[email protected]> --- Changes in v3: - Brought the MMU disable logic under CONFIG_QCOM_SNAGBOOT_SUPPORT ifdef condition - Moved the MMU disable codes to a new seperate file - Used "if (IS_ENABLED(CONFIG_QCOM_COMMAND_DB_OPTIONAL))" instead of #ifdef - Removed enabling QCOM_COMMAND_DB_OPTIONAL, ENABLE_ARM_SOC_BOOT0_HOOK and SKIP_RELOCATE as they are now automatically enabled by QCOM_SNAGBOOT_SUPPORT selection - Removed updating MAINTAINERS as the defconfig file is picked up by the "N: qcom" line - Link to v2: https://lore.kernel.org/u-boot/[email protected]/ Changes in v2: - Changed SYSRESET_PSCI from 'select' to 'imply' - Guard show_psci_version() and qcom_psci_fixup() with CONFIG_ARM_SMCCC - Disables the MMU and invalidates TLBs at the earliest entry point - Add qcom_lemans_snagboot_defconfig for Lemans-EVK - Link to v1: https://lore.kernel.org/u-boot/[email protected]/ --- Balaji Selvanathan (6): arm: snapdragon: Make SYSRESET_PSCI optional arm: snapdragon: Guard PSCI functions with CONFIG_ARM_SMCCC arm: snapdragon: Add CONFIG_QCOM_SNAGBOOT_SUPPORT option arm: snapdragon: Disable MMU early before U-Boot reset vector soc: qcom: cmd-db: Allow boot without CMD DB data configs: add qcom_lemans_snagboot_defconfig for Lemans-EVK arch/arm/Kconfig | 2 +- arch/arm/mach-snapdragon/Kconfig | 13 ++++++ arch/arm/mach-snapdragon/board.c | 6 +++ arch/arm/mach-snapdragon/include/mach/boot0.h | 2 + .../mach-snapdragon/include/mach/snagboot_boot0.h | 53 ++++++++++++++++++++++ configs/qcom_lemans_snagboot_defconfig | 45 ++++++++++++++++++ drivers/soc/qcom/Kconfig | 18 ++++++++ drivers/soc/qcom/cmd-db.c | 14 +++++- 8 files changed, 150 insertions(+), 3 deletions(-) --- base-commit: e1c3db1f788ed8106840e81b795e030cbe0020b7 change-id: 20260616-sngboot-760714938d18 Best regards, -- Balaji Selvanathan <[email protected]>
