menu "SPL / TPL" config SUPPORT_SPL bool config SUPPORT_TPL bool config SPL_DFU_NO_RESET bool config SPL bool depends on SUPPORT_SPL prompt "Enable SPL" help If you want to build SPL as well as the normal image, say Y. if SPL config SPL_LDSCRIPT string "Linker script for the SPL stage" default "arch/$(ARCH)/cpu/u-boot-spl.lds" depends on SPL help The SPL stage will usually require a different linker-script (as it runs from a different memory region) than the regular U-Boot stage. Set this to the path of the linker-script to be used for SPL. config SPL_BOARD_INIT bool "Call board-specific initialization in SPL" help If this option is enabled, U-Boot will call the function spl_board_init() from board_init_r(). This function should be provided by the board. config SPL_BOOTROM_SUPPORT bool "Support returning to the BOOTROM" help Some platforms (e.g. the Rockchip RK3368) provide support in their ROM for loading the next boot-stage after performing basic setup from the SPL stage. Enable this option, to return to the BOOTROM through the BOOT_DEVICE_BOOTROM (or fall-through to the next boot device in the boot device list, if not implemented for a given board) config SPL_RAW_IMAGE_SUPPORT bool "Support SPL loading and booting of RAW images" default n if (ARCH_MX6 && (SPL_MMC_SUPPORT || SPL_SATA_SUPPORT)) default y if !TI_SECURE_DEVICE help SPL will support loading and booting a RAW image when this option is y. If this is not set, SPL will move on to other available boot media to find a suitable image. config SPL_LEGACY_IMAGE_SUPPORT bool "Support SPL loading and booting of Legacy images" default y if !TI_SECURE_DEVICE help SPL will support loading and booting Legacy images when this option is y. If this is not set, SPL will move on to other available boot media to find a suitable image. config SPL_SYS_MALLOC_SIMPLE bool prompt "Only use malloc_simple functions in the SPL" help Say Y here to only use the *_simple malloc functions from malloc_simple.c, rather then using the versions from dlmalloc.c; this will make the SPL binary smaller at the cost of more heap usage as the *_simple malloc functions do not re-use free-ed mem. config TPL_SYS_MALLOC_SIMPLE bool prompt "Only use malloc_simple functions in the TPL" help Say Y here to only use the *_simple malloc functions from malloc_simple.c, rather then using the versions from dlmalloc.c; this will make the TPL binary smaller at the cost of more heap usage as the *_simple malloc functions do not re-use free-ed mem. config SPL_STACK_R bool "Enable SDRAM location for SPL stack" help SPL starts off execution in SRAM and thus typically has only a small stack available. Since SPL sets up DRAM while in its board_init_f() function, it is possible for the stack to move there before board_init_r() is reached. This option enables a special SDRAM location for the SPL stack. U-Boot SPL switches to this after board_init_f() completes, and before board_init_r() starts. config SPL_STACK_R_ADDR depends on SPL_STACK_R hex "SDRAM location for SPL stack" default 0x82000000 if ARCH_OMAP2PLUS help Specify the address in SDRAM for the SPL stack. This will be set up before board_init_r() is called. config SPL_STACK_R_MALLOC_SIMPLE_LEN depends on SPL_STACK_R && SPL_SYS_MALLOC_SIMPLE hex "Size of malloc_simple heap after switching to DRAM SPL stack" default 0x100000 help Specify the amount of the stack to use as memory pool for malloc_simple after switching the stack to DRAM. This may be set to give board_init_r() a larger heap then the initial heap in SRAM which is limited to SYS_MALLOC_F_LEN bytes. config SPL_SEPARATE_BSS bool "BSS section is in a different memory region from text" help Some platforms need a large BSS region in SPL and can provide this because RAM is already set up. In this case BSS can be moved to RAM. This option should then be enabled so that the correct device tree location is used. Normally we put the device tree at the end of BSS but with this option enabled, it goes at _image_binary_end. config SPL_DISPLAY_PRINT bool "Display a board-specific message in SPL" help If this option is enabled, U-Boot will call the function spl_display_print() immediately after displaying the SPL console banner ("U-Boot SPL ..."). This function should be provided by the board. config SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR bool "MMC raw mode: by sector" default y if ARCH_SUNXI || ARCH_DAVINCI || ARCH_UNIPHIER ||ARCH_MX6 || \ ARCH_ROCKCHIP || ARCH_MVEBU || ARCH_SOCFPGA || \ ARCH_AT91 || ARCH_ZYNQ || ARCH_KEYSTONE || OMAP34XX || \ OMAP44XX || OMAP54XX || AM33XX || AM43XX help Use sector number for specifying U-Boot location on MMC/SD in raw mode. config SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR hex "Address on the MMC to load U-Boot from" depends on SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR default 0x50 if ARCH_SUNXI default 0x75 if ARCH_DAVINCI default 0x8a if ARCH_MX6 default 0x100 if ARCH_UNIPHIER default 0x140 if ARCH_MVEBU default 0x200 if ARCH_SOCFPGA || ARCH_AT91 default 0x300 if ARCH_ZYNQ || ARCH_KEYSTONE || OMAP34XX || OMAP44XX || \ OMAP54XX || AM33XX || AM43XX default 0x4000 if ARCH_ROCKCHIP help Address on the MMC to load U-Boot from, when the MMC is being used in raw mode. Units: MMC sectors (1 sector = 512 bytes). config SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION bool "MMC Raw mode: by partition" help Use a partition for loading U-Boot when using MMC/SD in raw mode. config SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION hex "Partition to use to load U-Boot from" depends on SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION default 1 help Partition on the MMC to load U-Boot from when the MMC is being used in raw mode config SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION_TYPE bool "MMC raw mode: by partition type" depends on DOS_PARTITION && SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION help Use partition type for specifying U-Boot partition on MMC/SD in raw mode. U-Boot will be loaded from the first partition of this type to be found. config SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION_TYPE hex "Partition Type on the MMC to load U-Boot from" depends on SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION_TYPE help Partition Type on the MMC to load U-Boot from, when the MMC is being used in raw mode. config SPL_CRC32_SUPPORT bool "Support CRC32" depends on SPL_FIT help Enable this to support CRC32 in FIT images within SPL. This is a 32-bit checksum value that can be used to verify images. This is the least secure type of checksum, suitable for detected accidental image corruption. For secure applications you should consider SHA1 or SHA256. config SPL_MD5_SUPPORT bool "Support MD5" depends on SPL_FIT help Enable this to support MD5 in FIT images within SPL. An MD5 checksum is a 128-bit hash value used to check that the image contents have not been corrupted. Note that MD5 is not considered secure as it is possible (with a brute-force attack) to adjust the image while still retaining the same MD5 hash value. For secure applications where images may be changed maliciously, you should consider SHA1 or SHA256. config SPL_SHA1_SUPPORT bool "Support SHA1" depends on SPL_FIT select SHA1 help Enable this to support SHA1 in FIT images within SPL. A SHA1 checksum is a 160-bit (20-byte) hash value used to check that the image contents have not been corrupted or maliciously altered. While SHA1 is fairly secure it is coming to the end of its life due to the expanding computing power avaiable to brute-force attacks. For more security, consider SHA256. config SPL_SHA256_SUPPORT bool "Support SHA256" depends on SPL_FIT select SHA256 help Enable this to support SHA256 in FIT images within SPL. A SHA256 checksum is a 256-bit (32-byte) hash value used to check that the image contents have not been corrupted. SHA256 is recommended for use in secure applications since (as at 2016) there is no known feasible attack that could produce a 'collision' with differing input data. Use this for the highest security. Note that only the SHA256 variant is supported: SHA512 and others are not currently supported in U-Boot. config SPL_FIT_IMAGE_TINY bool "Remove functionality from SPL FIT loading to reduce size" depends on SPL_FIT default y if MACH_SUN50I || MACH_SUN50I_H5 help Enable this to reduce the size of the FIT image loading code in SPL, if space for the SPL binary is very tight. This removes the detection of image types (which forces the first image to be treated as having a U-Boot style calling convention) and skips the recording of each loaded payload (i.e. loadable) into the FDT (modifying the loaded FDT to ensure this information is available to the next image invoked). config SPL_CPU_SUPPORT bool "Support CPU drivers" help Enable this to support CPU drivers in SPL. These drivers can set up CPUs and provide information about them such as the model and name. This can be useful in SPL since setting up the CPUs earlier may improve boot performance. Enable this option to build the drivers in drivers/cpu as part of an SPL build. config SPL_CRYPTO_SUPPORT bool "Support crypto drivers" help Enable crypto drivers in SPL. These drivers can be used to accelerate secure boot processing in secure applications. Enable this option to build the drivers in drivers/crypto as part of an SPL build. config SPL_HASH_SUPPORT bool "Support hashing drivers" select SHA1 select SHA256 help Enable hashing drivers in SPL. These drivers can be used to accelerate secure boot processing in secure applications. Enable this option to build system-specific drivers for hash acceleration as part of an SPL build. config SPL_DMA_SUPPORT bool "Support DMA drivers" help Enable DMA (direct-memory-access) drivers in SPL. These drivers can be used to handle memory-to-peripheral data transfer without the CPU moving the data. Enable this option to build the drivers in drivers/dma as part of an SPL build. config SPL_DRIVERS_MISC_SUPPORT bool "Support misc drivers" help Enable miscellaneous drivers in SPL. These drivers perform various tasks that don't fall nicely into other categories, Enable this option to build the drivers in drivers/misc as part of an SPL build, for those that support building in SPL (not all drivers do). config SPL_ENV_SUPPORT bool "Support an environment" help Enable environment support in SPL. The U-Boot environment provides a number of settings (essentially name/value pairs) which can control many aspects of U-Boot's operation. Normally this is not needed in SPL as it has a much simpler task with less configuration. But some boards use this to support 'Falcon' boot on EXT2 and FAT, where SPL boots directly into Linux without starting U-Boot first. Enabling this option will make env_get() and env_set() available in SPL. config SPL_SAVEENV bool "Support save environment" depends on SPL_ENV_SUPPORT select SPL_MMC_WRITE if ENV_IS_IN_MMC help Enable save environment support in SPL after setenv. By default the saveenv option is not provided in SPL, but some boards need this support in 'Falcon' boot, where SPL need to boot from different images based on environment variable set by OS. For example OS may set "reboot_image" environment variable to "recovery" inorder to boot recovery image by SPL. The SPL read "reboot_image" and act accordingly and change the reboot_image to default mode using setenv and save the environemnt. config SPL_ETH_SUPPORT bool "Support Ethernet" depends on SPL_ENV_SUPPORT help Enable access to the network subsystem and associated Ethernet drivers in SPL. This permits SPL to load U-Boot over an Ethernet link rather than from an on-board peripheral. Environment support is required since the network stack uses a number of environment variables. See also SPL_NET_SUPPORT. config SPL_EXT_SUPPORT bool "Support EXT filesystems" help Enable support for EXT2/3/4 filesystems with SPL. This permits U-Boot (or Linux in Falcon mode) to be loaded from an EXT filesystem from within SPL. Support for the underlying block device (e.g. MMC or USB) must be enabled separately. config SPL_FAT_SUPPORT bool "Support FAT filesystems" select FS_FAT help Enable support for FAT and VFAT filesystems with SPL. This permits U-Boot (or Linux in Falcon mode) to be loaded from a FAT filesystem from within SPL. Support for the underlying block device (e.g. MMC or USB) must be enabled separately. config SPL_FPGA_SUPPORT bool "Support FPGAs" help Enable support for FPGAs in SPL. Field-programmable Gate Arrays provide software-configurable hardware which is typically used to implement peripherals (such as UARTs, LCD displays, MMC) or accelerate custom processing functions, such as image processing or machine learning. Sometimes it is useful to program the FPGA as early as possible during boot, and this option can enable that within SPL. config SPL_GPIO_SUPPORT bool "Support GPIO" help Enable support for GPIOs (General-purpose Input/Output) in SPL. GPIOs allow U-Boot to read the state of an input line (high or low) and set the state of an output line. This can be used to drive LEDs, control power to various system parts and read user input. GPIOs can be useful in SPL to enable a 'sign-of-life' LED, for example. Enable this option to build the drivers in drivers/gpio as part of an SPL build. config SPL_I2C_SUPPORT bool "Support I2C" help Enable support for the I2C (Inter-Integrated Circuit) bus in SPL. I2C works with a clock and data line which can be driven by a one or more masters or slaves. It is a fairly complex bus but is widely used as it only needs two lines for communication. Speeds of 400kbps are typical but up to 3.4Mbps is supported by some hardware. I2C can be useful in SPL to configure power management ICs (PMICs) before raising the CPU clock speed, for example. Enable this option to build the drivers in drivers/i2c as part of an SPL build. config SPL_LIBCOMMON_SUPPORT bool "Support common libraries" help Enable support for common U-Boot libraries within SPL. These libraries include common code to deal with U-Boot images, environment and USB, for example. This option is enabled on many boards. Enable this option to build the code in common/ as part of an SPL build. config SPL_LIBDISK_SUPPORT bool "Support disk paritions" help Enable support for disk partitions within SPL. 'Disk' is something of a misnomer as it includes non-spinning media such as flash (as used in MMC and USB sticks). Partitions provide a way for a disk to be split up into separate regions, with a partition table placed at the start or end which describes the location and size of each 'partition'. These partitions are typically uses as individual block devices, typically with an EXT2 or FAT filesystem in each. This option enables whatever partition support has been enabled in U-Boot to also be used in SPL. It brings in the code in disk/. config SPL_LIBGENERIC_SUPPORT bool "Support generic libraries" help Enable support for generic U-Boot libraries within SPL. These libraries include generic code to deal with device tree, hashing, printf(), compression and the like. This option is enabled on many boards. Enable this option to build the code in lib/ as part of an SPL build. config SPL_MMC_SUPPORT bool "Support MMC" depends on MMC help Enable support for MMC (Multimedia Card) within SPL. This enables the MMC protocol implementation and allows any enabled drivers to be used within SPL. MMC can be used with or without disk partition support depending on the application (SPL_LIBDISK_SUPPORT). Enable this option to build the drivers in drivers/mmc as part of an SPL build. config SPL_MMC_WRITE bool "MMC/SD/SDIO card support for write operations in SPL" depends on SPL_MMC_SUPPORT default n help Enable write access to MMC and SD Cards in SPL config SPL_MPC8XXX_INIT_DDR_SUPPORT bool "Support MPC8XXX DDR init" help Enable support for DDR-SDRAM (double-data-rate synchronous dynamic random-access memory) on the MPC8XXX family within SPL. This allows DRAM to be set up before loading U-Boot into that DRAM, where it can run. config SPL_MTD_SUPPORT bool "Support MTD drivers" help Enable support for MTD (Memory Technology Device) within SPL. MTD provides a block interface over raw NAND and can also be used with SPI flash. This allows SPL to load U-Boot from supported MTD devices. See SPL_NAND_SUPPORT and SPL_ONENAND_SUPPORT for how to enable specific MTD drivers. config SPL_MUSB_NEW_SUPPORT bool "Support new Mentor Graphics USB" help Enable support for Mentor Graphics USB in SPL. This is a new driver used by some boards. Enable this option to build the drivers in drivers/usb/musb-new as part of an SPL build. The old drivers are in drivers/usb/musb. config SPL_NAND_SUPPORT bool "Support NAND flash" help Enable support for NAND (Negative AND) flash in SPL. NAND flash can be used to allow SPL to load U-Boot from supported devices. This enables the drivers in drivers/mtd/nand as part of an SPL build. config SPL_NET_SUPPORT bool "Support networking" help Enable support for network devices (such as Ethernet) in SPL. This permits SPL to load U-Boot over a network link rather than from an on-board peripheral. Environment support is required since the network stack uses a number of environment variables. See also SPL_ETH_SUPPORT. if SPL_NET_SUPPORT config SPL_NET_VCI_STRING string "BOOTP Vendor Class Identifier string sent by SPL" help As defined by RFC 2132 the vendor class identifier field can be sent by the client to identify the vendor type and configuration of a client. This is often used in practice to allow for the DHCP server to specify different files to load depending on if the ROM, SPL or U-Boot itself makes the request endif # if SPL_NET_SUPPORT config SPL_NO_CPU_SUPPORT bool "Drop CPU code in SPL" help This is specific to the ARM926EJ-S CPU. It disables the standard start.S start-up code, presumably so that a replacement can be used on that CPU. You should not enable it unless you know what you are doing. config SPL_NOR_SUPPORT bool "Support NOR flash" help Enable support for loading U-Boot from memory-mapped NOR (Negative OR) flash in SPL. NOR flash is slow to write but fast to read, and a memory-mapped device makes it very easy to access. Loading from NOR is typically achieved with just a memcpy(). config SPL_XIP_SUPPORT bool "Support XIP" depends on SPL help Enable support for execute in place of U-Boot or kernel image. There is no need to copy image from flash to ram if flash supports execute in place. Its very useful in systems having enough flash but not enough ram to load the image. config SPL_ONENAND_SUPPORT bool "Support OneNAND flash" help Enable support for OneNAND (Negative AND) flash in SPL. OneNAND is a type of NAND flash and therefore can be used to allow SPL to load U-Boot from supported devices. This enables the drivers in drivers/mtd/onenand as part of an SPL build. config SPL_OS_BOOT bool "Activate Falcon Mode" depends on !TI_SECURE_DEVICE default n help Enable booting directly to an OS from SPL. for more info read doc/README.falcon if SPL_OS_BOOT config SYS_OS_BASE hex "addr, where OS is found" depends on SPL_NOR_SUPPORT help Specify the address, where the OS image is found, which gets booted. endif # SPL_OS_BOOT config SPL_PCI_SUPPORT bool "Support PCI drivers" help Enable support for PCI in SPL. For platforms that need PCI to boot, or must perform some init using PCI in SPL, this provides the necessary driver support. This enables the drivers in drivers/pci as part of an SPL build. config SPL_PCH_SUPPORT bool "Support PCH drivers" help Enable support for PCH (Platform Controller Hub) devices in SPL. These are used to set up GPIOs and the SPI peripheral early in boot. This enables the drivers in drivers/pch as part of an SPL build. config SPL_POST_MEM_SUPPORT bool "Support POST drivers" help Enable support for POST (Power-on Self Test) in SPL. POST is a procedure that checks that the hardware (CPU or board) appears to be functionally correctly. It is a sanity check that can be performed before booting. This enables the drivers in post/drivers as part of an SPL build. config SPL_POWER_SUPPORT bool "Support power drivers" help Enable support for power control in SPL. This includes support for PMICs (Power-management Integrated Circuits) and some of the features provided by PMICs. In particular, voltage regulators can be used to enable/disable power and vary its voltage. That can be useful in SPL to turn on boot peripherals and adjust CPU voltage so that the clock speed can be increased. This enables the drivers in drivers/power, drivers/power/pmic and drivers/power/regulator as part of an SPL build. config SPL_RAM_SUPPORT bool "Support booting from RAM" default y if MICROBLAZE || ARCH_SOCFPGA || TEGRA || ARCH_ZYNQ help Enable booting of an image in RAM. The image can be preloaded or it can be loaded by SPL directly into RAM (e.g. using USB). config SPL_RAM_DEVICE bool "Support booting from preloaded image in RAM" depends on SPL_RAM_SUPPORT default y if MICROBLAZE || ARCH_SOCFPGA || TEGRA || ARCH_ZYNQ help Enable booting of an image already loaded in RAM. The image has to be already in memory when SPL takes over, e.g. loaded by the boot ROM. config SPL_RTC_SUPPORT bool "Support RTC drivers" help Enable RTC (Real-time Clock) support in SPL. This includes support for reading and setting the time. Some RTC devices also have some non-volatile (battery-backed) memory which is accessible if needed. This enables the drivers in drivers/rtc as part of an SPL build. config SPL_SATA_SUPPORT bool "Support loading from SATA" help Enable support for SATA (Serial AT attachment) in SPL. This allows use of SATA devices such as hard drives and flash drivers for loading U-Boot. SATA is used in higher-end embedded systems and can provide higher performance than MMC , at somewhat higher expense and power consumption. This enables loading from SATA using a configured device. config SPL_SERIAL_SUPPORT bool "Support serial" help Enable support for serial in SPL. This allows use of a serial UART for displaying messages while SPL is running. It also brings in printf() and panic() functions. This should normally be enabled unless there are space reasons not to. Even then, consider enabling USE_TINY_PRINTF which is a small printf() version. config SPL_SPI_FLASH_SUPPORT bool "Support SPI flash drivers" help Enable support for using SPI flash in SPL, and loading U-Boot from SPI flash. SPI flash (Serial Peripheral Bus flash) is named after the SPI bus that is used to connect it to a system. It is a simple but fast bidirectional 4-wire bus (clock, chip select and two data lines). This enables the drivers in drivers/mtd/spi as part of an SPL build. This normally requires SPL_SPI_SUPPORT. config SPL_SPI_SUPPORT bool "Support SPI drivers" help Enable support for using SPI in SPL. This is used for connecting to SPI flash for loading U-Boot. See SPL_SPI_FLASH_SUPPORT for more details on that. The SPI driver provides the transport for data between the SPI flash and the CPU. This option can be used to enable SPI drivers that are needed for other purposes also, such as a SPI PMIC. config SPL_THERMAL bool "Driver support for thermal devices" help Enable support for temperature-sensing devices. Some SoCs have on-chip temperature sensors to permit warnings, speed throttling or even automatic power-off when the temperature gets too high or low. Other devices may be discrete but connected on a suitable bus. config SPL_USB_HOST_SUPPORT bool "Support USB host drivers" help Enable access to USB (Universal Serial Bus) host devices so that SPL can load U-Boot from a connected USB peripheral, such as a USB flash stick. While USB takes a little longer to start up than most buses, it is very flexible since many different types of storage device can be attached. This option enables the drivers in drivers/usb/host as part of an SPL build. config SPL_USB_SUPPORT bool "Support loading from USB" depends on SPL_USB_HOST_SUPPORT help Enable support for USB devices in SPL. This allows use of USB devices such as hard drives and flash drivers for loading U-Boot. The actual drivers are enabled separately using the normal U-Boot config options. This enables loading from USB using a configured device. config SPL_USB_GADGET_SUPPORT bool "Suppport USB Gadget drivers" help Enable USB Gadget API which allows to enable USB device functions in SPL. if SPL_USB_GADGET_SUPPORT config SPL_USBETH_SUPPORT bool "Support USB Ethernet drivers" help Enable access to the USB network subsystem and associated drivers in SPL. This permits SPL to load U-Boot over a USB-connected Ethernet link (such as a USB Ethernet dongle) rather than from an onboard peripheral. Environment support is required since the network stack uses a number of environment variables. See also SPL_NET_SUPPORT and SPL_ETH_SUPPORT. config SPL_DFU_SUPPORT bool "Support DFU (Device Firmware Upgarde)" select SPL_HASH_SUPPORT select SPL_DFU_NO_RESET depends on SPL_RAM_SUPPORT help This feature enables the DFU (Device Firmware Upgarde) in SPL with RAM memory device support. The ROM code will load and execute the SPL built with dfu. The user can load binaries (u-boot/kernel) to selected device partition from host-pc using dfu-utils. This feature is useful to flash the binaries to factory or bare-metal boards using USB interface. choice bool "DFU device selection" depends on SPL_DFU_SUPPORT config SPL_DFU_RAM bool "RAM device" depends on SPL_DFU_SUPPORT && SPL_RAM_SUPPORT help select RAM/DDR memory device for loading binary images (u-boot/kernel) to the selected device partition using DFU and execute the u-boot/kernel from RAM. endchoice config SPL_USB_SDP_SUPPORT bool "Support SDP (Serial Download Protocol)" help Enable Serial Download Protocol (SDP) device support in SPL. This allows to download images into memory and execute (jump to) them using the same protocol as implemented by the i.MX family's boot ROM. endif config SPL_WATCHDOG_SUPPORT bool "Support watchdog drivers" help Enable support for watchdog drivers in SPL. A watchdog is typically a hardware peripheral which can reset the system when it detects no activity for a while (such as a software crash). This enables the drivers in drivers/watchdog as part of an SPL build. config SPL_YMODEM_SUPPORT bool "Support loading using Ymodem" help While loading from serial is slow it can be a useful backup when there is no other option. The Ymodem protocol provides a reliable means of transmitting U-Boot over a serial line for using in SPL, with a checksum to ensure correctness. config SPL_ATF bool "Support ARM Trusted Firmware" depends on ARM64 help ATF(ARM Trusted Firmware) is a component for ARM AArch64 which is loaded by SPL (which is considered as BL2 in ATF terminology). More detail at: https://github.com/ARM-software/arm-trusted-firmware config SPL_ATF_NO_PLATFORM_PARAM bool "Pass no platform parameter" depends on SPL_ATF help While we expect to call a pointer to a valid FDT (or NULL) as the platform parameter to an ATF, some ATF versions are not U-Boot aware and have an insufficiently robust parameter validation to gracefully reject a FDT being passed. If this option is enabled, the spl_atf os-type handler will always pass NULL for the platform parameter. If your ATF is affected, say Y. config TPL bool depends on SUPPORT_TPL prompt "Enable TPL" help If you want to build TPL as well as the normal image and SPL, say Y. if TPL config TPL_LDSCRIPT string "Linker script for the TPL stage" depends on TPL help The TPL stage will usually require a different linker-script (as it runs from a different memory region) than the regular U-Boot stage. Set this to the path of the linker-script to be used for TPL. May be left empty to trigger the Makefile infrastructure to fall back to the linker-script used for the SPL stage. config TPL_NEEDS_SEPARATE_TEXT_BASE bool "TPL needs a separate text-base" default n depends on TPL help Enable, if the TPL stage should not inherit its text-base from the SPL stage. When enabled, a base address for the .text sections of the TPL stage has to be set below. config TPL_NEEDS_SEPARATE_STACK bool "TPL needs a separate initial stack-pointer" default n depends on TPL help Enable, if the TPL stage should not inherit its initial stack-pointer from the settings for the SPL stage. config TPL_TEXT_BASE hex "Base address for the .text section of the TPL stage" depends on TPL_NEEDS_SEPARATE_TEXT_BASE help The base address for the .text section of the TPL stage. config TPL_MAX_SIZE int "Maximum size (in bytes) for the TPL stage" default 0 depends on TPL help The maximum size (in bytes) of the TPL stage. config TPL_STACK hex "Address of the initial stack-pointer for the TPL stage" depends on TPL_NEEDS_SEPARATE_STACK help The address of the initial stack-pointer for the TPL stage. Usually this will be the (aligned) top-of-stack. config TPL_BOOTROM_SUPPORT bool "Support returning to the BOOTROM (from TPL)" help Some platforms (e.g. the Rockchip RK3368) provide support in their ROM for loading the next boot-stage after performing basic setup from the TPL stage. Enable this option, to return to the BOOTROM through the BOOT_DEVICE_BOOTROM (or fall-through to the next boot device in the boot device list, if not implemented for a given board) config TPL_DRIVERS_MISC_SUPPORT bool "Support misc drivers in TPL" help Enable miscellaneous drivers in TPL. These drivers perform various tasks that don't fall nicely into other categories, Enable this option to build the drivers in drivers/misc as part of an TPL build, for those that support building in TPL (not all drivers do). config TPL_ENV_SUPPORT bool "Support an environment" help Enable environment support in TPL. See SPL_ENV_SUPPORT for details. config TPL_I2C_SUPPORT bool "Support I2C" help Enable support for the I2C bus in TPL. See SPL_I2C_SUPPORT for details. config TPL_LIBCOMMON_SUPPORT bool "Support common libraries" help Enable support for common U-Boot libraries within TPL. See SPL_LIBCOMMON_SUPPORT for details. config TPL_LIBGENERIC_SUPPORT bool "Support generic libraries" help Enable support for generic U-Boot libraries within TPL. See SPL_LIBGENERIC_SUPPORT for details. config TPL_MPC8XXX_INIT_DDR_SUPPORT bool "Support MPC8XXX DDR init" help Enable support for DDR-SDRAM on the MPC8XXX family within TPL. See SPL_MPC8XXX_INIT_DDR_SUPPORT for details. config TPL_MMC_SUPPORT bool "Support MMC" depends on MMC help Enable support for MMC within TPL. See SPL_MMC_SUPPORT for details. config TPL_NAND_SUPPORT bool "Support NAND flash" help Enable support for NAND in TPL. See SPL_NAND_SUPPORT for details. config TPL_SERIAL_SUPPORT bool "Support serial" help Enable support for serial in TPL. See SPL_SERIAL_SUPPORT for details. config TPL_SPI_FLASH_SUPPORT bool "Support SPI flash drivers" help Enable support for using SPI flash in TPL. See SPL_SPI_FLASH_SUPPORT for details. config TPL_SPI_SUPPORT bool "Support SPI drivers" help Enable support for using SPI in TPL. See SPL_SPI_SUPPORT for details. endif # TPL endif # SPL endmenu