[PATCH v4 1/8] arm: snapdragon: Add CONFIG_QCOM_SNAGBOOT_MODE option

[Balaji Selvanathan]

Add CONFIG_QCOM_SNAGBOOT_MODE to enable snagboot mode on Qualcomm
platforms. This config automatically selects the required dependencies.

Add QCOM_BOOT0_SNAGBOOT_MODE as boot0.h config for automatic selection
by QCOM_SNAGBOOT_MODE. Document the platform-specific requirements and
configs that must be disabled in snagboot mode.

Signed-off-by: Balaji Selvanathan <balaji.selvanathan at oss.qualcomm.com>
---
Changes in v4:
- Renamed QCOM_SNAGBOOT_SUPPORT to QCOM_SNAGBOOT_MODE
- Added QCOM_BOOT0_SNAGBOOT_MODE for boot0.h which gets selected by
  QCOM_SNAGBOOT_MODE
- Document the platform-specific requirements and configs that must be
  disabled in snagboot mode.

Changes in v3:
- Newly introduced in v3
---
 arch/arm/mach-snapdragon/Kconfig | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/arch/arm/mach-snapdragon/Kconfig b/arch/arm/mach-snapdragon/Kconfig
index 931d25c1023..5c7dbe0dcc4 100644
--- a/arch/arm/mach-snapdragon/Kconfig
+++ b/arch/arm/mach-snapdragon/Kconfig
@@ -65,4 +65,32 @@ config QCOM_EL2_GUNYAH_EXIT_SUPPORT
 	  run properly at EL2.
 endchoice
 
+config QCOM_BOOT0_SNAGBOOT_MODE
+	bool "boot0.h initialization for Snagboot mode"
+	help
+	  Enable boot0.h early initialization required when U-Boot
+	  is loaded in Snagboot mode by XBL.
+
+config QCOM_SNAGBOOT_MODE
+	bool "Build U-Boot for Snagboot mode loading"
+	select QCOM_BOOT0_SNAGBOOT_MODE
+	select ENABLE_ARM_SOC_BOOT0_HOOK
+	select SKIP_RELOCATE
+	help
+	  Build U-Boot to be loaded in Snagboot mode on Qualcomm platforms
+	  for device/factory provisioning using fastboot.
+
+	  Snagboot mode requires disabling several configs in your defconfig:
+	  - PSCI_RESET: Not available in Snagboot mode
+	  - IOMMU: Not initialized by XBL in Snagboot mode
+	  - SAVE_PREV_BL_INITRAMFS_START_ADDR: Previous bootloader context
+	    is not preserved in snagboot mode
+	  - REBOOT_MODE_ENV_UPDATE: Not applicable in device/factory provisioning mode
+
+	  Additionally, use CONFIG_ENV_IS_NOWHERE to ensure recovery works
+	  even with corrupted environment storage.
+
+	  Platform-specific requirements:
+	  - Set CONFIG_COUNTER_FREQUENCY to match your platform's timer
+	  - Configure CONFIG_TEXT_BASE for U-Boot load address
 endif

-- 
2.34.1