Hi Casey,
On 6/16/2026 5:56 PM, Casey Connolly wrote:
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.
Sorry, missed replying to you regarding v3 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.
Sure, will include a patch having documentation in v4 respin.
I would hope that this support will be expanded to other platforms, and
I'll make that assumption with my feedback.
Yes, currently we are supporting for Lemans EVK. The plan is to to
support other platforms in future.
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.
Sure.
Thanks,
Balaji
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,
