[PATCH v4 0/8] arm: snapdragon: Add snagboot support for Lemans-EVK
Balaji Selvanathan
balaji.selvanathan at oss.qualcomm.com
Fri Jun 19 13:10:23 CEST 2026
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 EDL mode 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 EDL 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.
Support for Qualcomm Lemans-EVK SOC in Snagboot is now available in
https://github.com/qualcomm-linux/snagboot/tree/qcom-next
Soon these Snagboot changes will be upstreamed to https://github.com/bootlin/snagboot
When U-Boot executes in Snagboot flow, it has to deal with missing
platform services such as TrustZone (TZ), Hypervisor and AOP (which
populates CMD DB data).
This series addresses these issues by following patches:
Patch 1 adds CONFIG_QCOM_SNAGBOOT_MODE option to enable snagboot
mode support on Qualcomm platforms.
Patch 2 changes SYSRESET_PSCI from 'select' to 'imply' so it can
be disabled as PSCI firmware is unavailable in Snagboot mode.
Patch 3 guards show_psci_version() and qcom_psci_fixup() with
CONFIG_ARM_SMCCC to prevent build failures when SMCCC is disabled.
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 allows the CMD DB driver to bind successfully when CMD DB data
is not populated by XBL, logging a warning instead of failing.
Patch 6 removes Lemans EVK override DTS
Patch 7 adds qcom_lemans_snagboot_defconfig for Lemans-EVK, based
on qcom_defconfig with snagboot-specific settings.
Patch 8 adds documentation for U-Boot snagboot mode support on
Qualcomm platforms.
This series depends on the following patches/series:
https://lore.kernel.org/all/20260508-qcom_spl-v7-4-7d0e22aaaa8f@seznam.cz/
https://lore.kernel.org/u-boot/20260515130934.388894-1-aswin.murugan@oss.qualcomm.com/
https://lore.kernel.org/u-boot/20260618-b4-modernise-smem-v3-0-472391477988@linaro.org/
https://lore.kernel.org/u-boot/20260427-ufs_clk-v2-0-36e10a7c0ef6@oss.qualcomm.com/ (already picked in u-boot/next as of 19th June 2026)
Signed-off-by: Balaji Selvanathan <balaji.selvanathan at oss.qualcomm.com>
---
Changes in v4:
- Renamed QCOM_SNAGBOOT_SUPPORT to QCOM_SNAGBOOT_MODE
- Make SYSRESET_PSCI dependent on QCOM_SNAGBOOT_MODE
- Place Snagboot related configs in seperate config fragment
called configs/qcom-snagboot.config
- Include above config fragment in
configs/qcom_lemans_snagboot_defconfig
- Removed Lemans EVK override dtsi: arch/arm/dts/lemans-evk-u-boot.dtsi
- Removed QCOM_COMMAND_DB_OPTIONAL as now we use
CONFIG_QCOM_SNAGBOOT_MODE
- Added documentation on U-Boot for Snagboot
- Link to v3: https://lore.kernel.org/u-boot/20260616-sngboot-v3-0-6fb0dee8125c@oss.qualcomm.com/
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/20260608-snagboot-v2-0-036bb0343bf7@oss.qualcomm.com/
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/20260409-cmddb-v1-1-b10549b34133@oss.qualcomm.com/
---
Balaji Selvanathan (8):
arm: snapdragon: Add CONFIG_QCOM_SNAGBOOT_MODE option
arm: snapdragon: Make SYSRESET_PSCI optional
arm: snapdragon: Guard PSCI functions with CONFIG_ARM_SMCCC
arm: snapdragon: Disable MMU early before U-Boot reset vector
soc: qcom: cmd-db: Allow boot without CMD DB data
arch: arm: dts: remove Lemans EVK override DTS
configs: add qcom_lemans_snagboot_defconfig for Lemans-EVK
doc: qualcomm: Add snagboot mode documentation
arch/arm/Kconfig | 2 +-
arch/arm/dts/lemans-evk-u-boot.dtsi | 19 ---
arch/arm/mach-snapdragon/Kconfig | 28 ++++
arch/arm/mach-snapdragon/board.c | 6 +
arch/arm/mach-snapdragon/include/mach/boot0.h | 2 +
.../mach-snapdragon/include/mach/snagboot_boot0.h | 26 +++
configs/qcom-snagboot.config | 33 ++++
configs/qcom_lemans_snagboot_defconfig | 18 ++
doc/board/qualcomm/index.rst | 1 +
doc/board/qualcomm/snagboot.rst | 184 +++++++++++++++++++++
drivers/soc/qcom/Kconfig | 18 ++
drivers/soc/qcom/cmd-db.c | 15 +-
12 files changed, 330 insertions(+), 22 deletions(-)
---
base-commit: ff70c8fdcf2fe81acba632b606af16d5a041631f
change-id: 20260619-snagboot-625d778c59fc
Best regards,
--
Balaji Selvanathan <balaji.selvanathan at oss.qualcomm.com>
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