[PATCH v3 0/6] arm: snapdragon: Add snagboot support for Lemans-EVK

[Casey Connolly]

Hi Balaji,

On 16/06/2026 11:22, Balaji Selvanathan wrote:
> This series adds support for running U-Boot in snagboot mode on
> Qualcomm Snapdragon platforms, targeting the Lemans-EVK board.

You didn't respond to my reply on v2 of this series.
> 
> 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.

Glad to have some more info here. Please also add a doc page with this
information as well as a list of supported platforms.

I would hope that this support will be expanded to other platforms, and
I'll make that assumption with my feedback.

> 
> 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

recovery mode?? Please be consistent and just say EDL or boot ROM.

> 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 <balaji.selvanathan at 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 (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,

-- 
// Casey (she/her)