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. config SPL_FRAMEWORK bool "Support SPL based upon the common SPL framework" depends on SPL default y help Enable the SPL framework under common/spl/. This framework supports MMC, NAND and YMODEM and other methods loading of U-Boot and the Linux Kernel. If unsure, say Y. config SPL_FRAMEWORK_BOARD_INIT_F bool "Define a generic function board_init_f" depends on SPL_FRAMEWORK help Define a generic function board_init_f that: - initialize the spl (spl_early_init) - initialize the serial (preloader_console_init) Unless you want to provide your own board_init_f, you should say Y. config SPL_SIZE_LIMIT hex "Maximum size of SPL image" depends on SPL default 69632 if ARCH_MX6 && !MX6_OCRAM_256KB default 200704 if ARCH_MX6 && MX6_OCRAM_256KB default 0 help Specifies the maximum length of the U-Boot SPL image. If this value is zero, it is ignored. config SPL_SIZE_LIMIT_SUBTRACT_GD bool "SPL image size check: provide space for global data" depends on SPL_SIZE_LIMIT > 0 help If enabled, aligned size of global data is reserved in SPL_SIZE_LIMIT check to ensure such an image does not overflow SRAM if SPL_SIZE_LIMIT describes the size of SRAM available for SPL when pre-reloc global data is put into this SRAM, too. config SPL_SIZE_LIMIT_SUBTRACT_MALLOC bool "SPL image size check: provide space for malloc() pool before relocation" depends on SPL_SIZE_LIMIT > 0 help If enabled, SPL_SYS_MALLOC_F_LEN is reserved in SPL_SIZE_LIMIT check to ensure such an image does not overflow SRAM if SPL_SIZE_LIMIT describes the size of SRAM available for SPL when pre-reloc malloc pool is put into this SRAM, too. config SPL_SIZE_LIMIT_PROVIDE_STACK hex "SPL image size check: provide stack space before relocation" depends on SPL_SIZE_LIMIT > 0 default 0 help If set, this size is reserved in SPL_SIZE_LIMIT check to ensure such an image does not overflow SRAM if SPL_SIZE_LIMIT describes the size of SRAM available for SPL when the stack required before reolcation uses this SRAM, too. config SPL_SYS_STACK_F_CHECK_BYTE hex default 0xaa help Constant used to check the stack config SPL_SYS_REPORT_STACK_F_USAGE depends on SPL_SIZE_LIMIT_PROVIDE_STACK != 0 bool "Check and report stack usage in SPL before relocation" help If this option is enabled, the initial SPL stack is filled with 0xaa very early, up to the size configured with SPL_SIZE_LIMIT_PROVIDE_STACK. Later when SPL is done using this initial stack and switches to a stack in DRAM, the actually used size of this initial stack is reported by examining the memory and searching for the lowest occurrence of non 0xaa bytes. This default implementation works for stacks growing down only. menu "PowerPC and LayerScape SPL Boot options" config SPL_NAND_BOOT bool "Load SPL from NAND flash" depends on PPC && (SUPPORT_SPL && !SPL_FRAMEWORK) config SPL_MMC_BOOT bool "Load SPL from SD Card / eMMC" depends on PPC && (SUPPORT_SPL && !SPL_FRAMEWORK) config SPL_SPI_BOOT bool "Load SPL from SPI flash" depends on PPC && (SUPPORT_SPL && !SPL_FRAMEWORK) config SPL_FSL_PBL bool "Create SPL in Freescale PBI format" depends on (PPC || ARCH_LS1021A || ARCH_LS1043A || ARCH_LS1046A) && \ SUPPORT_SPL help Create boot binary having SPL binary in PBI format concatenated with u-boot binary. endmenu config HANDOFF bool "Pass hand-off information from SPL to U-Boot proper" depends on BLOBLIST help It is useful to be able to pass information from SPL to U-Boot proper to preserve state that is known in SPL and is needed in U-Boot. Enable this to locate the handoff information in U-Boot proper, early in boot. It is available in gd->handoff. The state state is set up in SPL (or TPL if that is being used). if SPL config SPL_HANDOFF bool "Pass hand-off information from SPL to U-Boot proper" depends on HANDOFF && SPL_BLOBLIST default y help This option enables SPL to write handoff information. This can be used to pass information like the size of SDRAM from SPL to U-Boot proper. Also SPL can receive information from TPL in the same place if that is enabled. config SPL_LDSCRIPT string "Linker script for the SPL stage" default "arch/$(ARCH)/cpu/u-boot-spl.lds" 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_TEXT_BASE hex "SPL Text Base" default ISW_ENTRY_ADDR if AM43XX || AM33XX || OMAP54XX || ARCH_KEYSTONE default 0x10060 if MACH_SUN50I || MACH_SUN50I_H5 || MACH_SUN9I default 0x20060 if MACH_SUN50I_H6 default 0x00060 if ARCH_SUNXI default 0xfffc0000 if ARCH_ZYNQMP default 0x0 help The address in memory that SPL will be running from. 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_BOOTCOUNT_LIMIT bool "Support bootcount in SPL" depends on SPL_ENV_SUPPORT help On some boards, which use 'falcon' mode, it is necessary to check and increment the number of boot attempts. Such boards do not use proper U-Boot for normal boot flow and hence needs those adjustments to be done in the SPL. 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 && !SPL_LOAD_FIT 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_LEGACY_IMAGE_CRC_CHECK bool "Check CRC of Legacy images" depends on SPL_LEGACY_IMAGE_SUPPORT select SPL_CRC32_SUPPORT help Enable this to check the CRC of Legacy images. While this increases reliability, it affects both code size and boot duration. If disabled, Legacy images are booted if the image magic and size are correct, without further integrity checks. 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" depends on 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_BANNER_PRINT bool "Enable output of the SPL banner 'U-Boot SPL ...'" default y help If this option is enabled, SPL will print the banner with version info. Disabling this option could be useful to reduce SPL boot time (e.g. approx. 6 ms faster, when output on i.MX6 with 115200 baud). config TPL_BANNER_PRINT bool "Enable output of the TPL banner 'U-Boot TPL ...'" depends on TPL default y help If this option is enabled, TPL will print the banner with version info. Disabling this option could be useful to reduce TPL boot time (e.g. approx. 6 ms faster, when output on i.MX6 with 115200 baud). config SPL_EARLY_BSS depends on ARM && !ARM64 bool "Allows initializing BSS early before entering board_init_f" help On some platform we have sufficient memory available early on to allow setting up and using a basic BSS prior to entering board_init_f. Activating this option will also de-activate the clearing of BSS during the SPL relocation process, thus allowing to carry state from board_init_f to board_init_r by way of BSS. 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_MX7 || \ 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 || ARCH_MX7 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 || ARCH_K3 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_DATA_PART_OFFSET hex "U-Boot main hardware partition image offset" depends on SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR default 0x0 help On some platforms SPL location depends on hardware partition. The ROM code skips the MBR sector when loading SPL from main hardware data partition. This adds offset to the main U-Boot image. Set this symbol to the number of skipped sectors. If unsure, leave the default. 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 SUPPORT_EMMC_BOOT_OVERRIDE_PART_CONFIG bool "Override eMMC EXT_CSC_PART_CONFIG by user defined partition" depends on SUPPORT_EMMC_BOOT help eMMC boot partition is normally configured by the bits of the EXT_CSD register (EXT_CSC_PART_CONFIG), BOOT_PARTITION_ENABLE field. In some cases it might be required in SPL to load the image from different partition than the partition selected by EXT_CSC_PART_CONFIG register. Enable this option if you intend to use an eMMC boot partition other then selected via EXT_CSC_PART_CONFIG register and specify the custom partition number by the CONFIG_SYS_MMCSD_RAW_MODE_EMMC_BOOT_PARTITION option. config SYS_MMCSD_RAW_MODE_EMMC_BOOT_PARTITION int "Number of the eMMC boot partition to use" depends on SUPPORT_EMMC_BOOT_OVERRIDE_PART_CONFIG default 1 help eMMC boot partition number to use when the eMMC in raw mode and the eMMC EXT_CSC_PART_CONFIG selection should be overridden in SPL by user defined partition number. config SPL_CRC32_SUPPORT bool "Support CRC32" default y if SPL_LEGACY_IMAGE_SUPPORT help Enable this to support CRC32 in uImages or FIT images within SPL. This is a 32-bit checksum value that can be used to verify images. For FIT 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 available 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 || MACH_SUN50I_H6 default y if ARCH_IMX8M 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_CACHE_SUPPORT bool "Support CACHE drivers" help Enable CACHE drivers in SPL. These drivers can keep data so that future requests for that data can be served faster. Enable this option to build the drivers in drivers/cache as part of an SPL build. 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 TPL_HASH_SUPPORT bool "Support hashing drivers in TPL" depends on TPL 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 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_DM_GPIO bool "Support Driver Model GPIO drivers" depends on SPL_GPIO_SUPPORT && DM_GPIO help Enable support for Driver Model based GPIO drivers in SPL. 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 environment. 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_FS_EXT4 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_FS_FAT 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_FAT_WRITE bool "Support write for FAT filesystems" help Enable write support for FAT and VFAT filesystems with 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 in SPL" 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 partitions" select PARTITIONS 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_DM_MAILBOX bool "Support Mailbox" help Enable support for Mailbox within SPL. This enable the inter processor communication protocols tobe used within SPL. Enable this option to build the drivers in drivers/mailbox as part of SPL build. config SPL_MMC_SUPPORT bool "Support MMC" depends on MMC select HAVE_BLOCK_DEVICE 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_FORCE_MMC_BOOT bool "Force SPL booting from MMC" depends on SPL_MMC_SUPPORT default n help Force SPL to use MMC device for Linux kernel booting even when the SoC ROM recognized boot medium is not eMMC/SD. This is crucial for factory or 'falcon mode' booting. config SPL_MMC_TINY bool "Tiny MMC framework in SPL" depends on SPL_MMC_SUPPORT default n help Enable MMC framework tinification support. This option is useful if if your SPL is extremely size constrained. Heed the warning, enable this option if and only if you know exactly what you are doing, if you are reading this help text, you most likely have no idea :-) The MMC framework is reduced to bare minimum to be useful. No malloc support is needed for the MMC framework operation with this option enabled. The framework supports exactly one MMC device and exactly one MMC driver. The MMC driver can be adjusted to avoid any malloc operations too, which can remove the need for malloc support in SPL and thus further reduce footprint. 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/raw as part of an SPL build. config SPL_UBI bool "Support UBI" help Enable support for loading payloads from UBI. See README.ubispl for more info. if SPL_DM config SPL_CACHE depends on CACHE bool "Support cache drivers in SPL" help Enable support for cache drivers in SPL. config SPL_DM_SPI bool "Support SPI DM drivers in SPL" help Enable support for SPI DM drivers in SPL. endif if SPL_UBI config SPL_UBI_LOAD_BY_VOLNAME bool "Support loading volumes by name" help This enables support for loading UBI volumes by name. When this is set, CONFIG_SPL_UBI_LOAD_MONITOR_VOLNAME can be used to configure the volume name from which to load U-Boot. config SPL_UBI_MAX_VOL_LEBS int "Maximum number of LEBs per volume" depends on SPL_UBI help The maximum number of logical eraseblocks which a static volume to load can contain. Used for sizing the scan data structure. config SPL_UBI_MAX_PEB_SIZE int "Maximum PEB size" depends on SPL_UBI help The maximum physical erase block size. config SPL_UBI_MAX_PEBS int "Maximum number of PEBs" depends on SPL_UBI help The maximum physical erase block size. If not overridden by board code, this value will be used as the actual number of PEBs. config SPL_UBI_PEB_OFFSET int "Offset to first UBI PEB" depends on SPL_UBI help The offset in number of PEBs from the start of flash to the first PEB part of the UBI image. config SPL_UBI_VID_OFFSET int "Offset to VID header" depends on SPL_UBI config SPL_UBI_LEB_START int "Offset to LEB in PEB" depends on SPL_UBI help The offset in bytes to the LEB within a PEB. config SPL_UBI_INFO_ADDR hex "Address to place UBI scan info" depends on SPL_UBI help Address for ubispl to place the scan info. Read README.ubispl to determine the required size config SPL_UBI_VOL_IDS int "Maximum volume id" depends on SPL_UBI help The maximum volume id which can be loaded. Used for sizing the scan data structure. config SPL_UBI_LOAD_MONITOR_ID int "id of U-Boot volume" depends on SPL_UBI help The UBI volume id from which to load U-Boot config SPL_UBI_LOAD_MONITOR_VOLNAME string "volume name of U-Boot volume" depends on SPL_UBI_LOAD_BY_VOLNAME help The UBI volume name from which to load U-Boot config SPL_UBI_LOAD_KERNEL_ID int "id of kernel volume" depends on SPL_OS_BOOT && SPL_UBI help The UBI volume id from which to load the kernel config SPL_UBI_LOAD_ARGS_ID int "id of kernel args volume" depends on SPL_OS_BOOT && SPL_UBI help The UBI volume id from which to load the device tree config UBI_SPL_SILENCE_MSG bool "silence UBI SPL messages" default n help Disable messages from UBI SPL. This leaves warnings and errors enabled. endif # if SPL_UBI 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_PAYLOAD string "SPL payload" default "tpl/u-boot-with-tpl.bin" if TPL default "u-boot.bin" help Payload for SPL boot. For backward compatibility, default to u-boot.bin, i.e. RAW image without any header. In case of TPL, tpl/u-boot-with-tpl.bin. For new boards, suggest to use u-boot.img. config SPL_PCI 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_DM_RESET bool "Support reset drivers" depends on SPL help Enable support for reset control in SPL. That can be useful in SPL to handle IP reset in driver, as in U-Boot, by using the generic reset API provided by driver model. This enables the drivers in drivers/reset 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_POWER_DOMAIN bool "Support power domain drivers" help Enable support for power domain control in SPL. Many SoCs allow power to be applied to or removed from portions of the SoC (power domains). This may be used to save power. This API provides the means to control such power management hardware. This enables the drivers in drivers/power/domain as part of a 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_REMOTEPROC bool "Support REMOTEPROCS" help Enable support for REMOTEPROCs in SPL. This permits to load a remote processor firmware in SPL. 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_SATA_RAW_U_BOOT_USE_SECTOR bool "SATA raw mode: by sector" depends on SPL_SATA_SUPPORT help Use sector number for specifying U-Boot location on SATA disk in raw mode. config SPL_SATA_RAW_U_BOOT_SECTOR hex "Sector on the SATA disk to load U-Boot from" depends on SPL_SATA_RAW_U_BOOT_USE_SECTOR help Sector on the SATA disk to load U-Boot from, when the SATA disk is being used in raw mode. Units: SATA disk sectors (1 sector = 512 bytes). config SPL_SERIAL_SUPPORT bool "Support serial" select SPL_PRINTF select SPL_STRTO 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 SPL_USE_TINY_PRINTF which is a small printf() version. 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_SPI_FLASH_SUPPORT bool "Support SPI flash drivers" depends on SPL_SPI_SUPPORT 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. if SPL_SPI_FLASH_SUPPORT config SPL_SPI_FLASH_TINY bool "Enable low footprint SPL SPI Flash support" depends on !SPI_FLASH_BAR default y if SPI_FLASH help Enable lightweight SPL SPI Flash support that supports just reading data/images from flash. No support to write/erase flash. Enable this if you have SPL size limitations and don't need full fledged SPI flash support. config SPL_SPI_FLASH_SFDP_SUPPORT bool "SFDP table parsing support for SPI NOR flashes" depends on !SPI_FLASH_BAR && !SPL_SPI_FLASH_TINY help Enable support for parsing and auto discovery of parameters for SPI NOR flashes using Serial Flash Discoverable Parameters (SFDP) tables as per JESD216 standard in SPL. config SPL_SPI_LOAD bool "Support loading from SPI flash" help Enable support for loading next stage, U-Boot or otherwise, from SPI NOR in U-Boot SPL. endif # SPL_SPI_FLASH_SUPPORT config SYS_SPI_U_BOOT_OFFS hex "address of u-boot payload in SPI flash" default 0x8000 if ARCH_SUNXI default 0x0 depends on SPL_SPI_LOAD || SPL_SPI_SUNXI help Address within SPI-Flash from where the u-boot payload is fetched from. 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" select HAVE_BLOCK_DEVICE 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_STORAGE bool "Support loading from USB" depends on SPL_USB_HOST_SUPPORT && !(BLK && !DM_USB) 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 bool "Suppport USB Gadget drivers" help Enable USB Gadget API which allows to enable USB device functions in SPL. if SPL_USB_GADGET config SPL_USB_ETHER 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 bool "Support DFU (Device Firmware Upgrade)" select SPL_HASH_SUPPORT select SPL_DFU_NO_RESET depends on SPL_RAM_SUPPORT help This feature enables the DFU (Device Firmware Upgrade) 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 config SPL_DFU_RAM bool "RAM device" depends on SPL_DFU && 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" imply SPL_WDT if !HW_WATCHDOG 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" depends on SPL_SERIAL_SUPPORT 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 SPL_AM33XX_ENABLE_RTC32K_OSC bool "Enable the RTC32K OSC on AM33xx based platforms" default y if AM33XX help Enable access to the AM33xx RTC and select the external 32kHz clock source. config SPL_OPTEE bool "Support OP-TEE Trusted OS" depends on ARM help OP-TEE is an open source Trusted OS which is loaded by SPL. More detail at: https://github.com/OP-TEE/optee_os config SPL_OPENSBI bool "Support RISC-V OpenSBI" depends on RISCV && SPL_RISCV_MMODE && RISCV_SMODE help OpenSBI is an open-source implementation of the RISC-V Supervisor Binary Interface (SBI) specification. U-Boot supports the OpenSBI FW_DYNAMIC firmware. It is loaded and started by U-Boot SPL. More details are available at https://github.com/riscv/opensbi and https://github.com/riscv/riscv-sbi-doc config SPL_OPENSBI_LOAD_ADDR hex "OpenSBI load address" depends on SPL_OPENSBI help Load address of the OpenSBI binary. 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_SIZE_LIMIT hex "Maximum size of TPL image" depends on TPL default 0 help Specifies the maximum length of the U-Boot TPL image. If this value is zero, it is ignored. config TPL_FRAMEWORK bool "Support TPL based upon the common SPL framework" default y if SPL_FRAMEWORK help Enable the SPL framework under common/spl/ for TPL builds. This framework supports MMC, NAND and YMODEM and other methods loading of U-Boot's SPL stage. If unsure, say Y. config TPL_HANDOFF bool "Pass hand-off information from TPL to SPL and U-Boot proper" depends on HANDOFF && TPL_BLOBLIST default y help This option enables TPL to write handoff information. This can be used to pass information like the size of SDRAM from TPL to U-Boot proper. The information is also available to SPL if it is useful there. config TPL_BOARD_INIT bool "Call board-specific initialization in TPL" 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 TPL_LDSCRIPT string "Linker script for the TPL stage" depends on TPL default "arch/arm/cpu/armv8/u-boot-spl.lds" if ARM64 default "arch/$(ARCH)/cpu/u-boot-spl.lds" 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_GPIO_SUPPORT bool "Support GPIO in TPL" help Enable support for GPIOs (General-purpose Input/Output) in TPL. 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 TPL to enable a 'sign-of-life' LED, for example. Enable this option to build the drivers in drivers/gpio as part of an TPL build. 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_PCI bool "Support PCI drivers" help Enable support for PCI in TPL. 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 a TPL build. config TPL_PCH_SUPPORT bool "Support PCH drivers" help Enable support for PCH (Platform Controller Hub) devices in TPL. These are used to set up GPIOs and the SPI peripheral early in boot. This enables the drivers in drivers/pch as part of a TPL build. config TPL_RAM_SUPPORT bool "Support booting from RAM" help Enable booting of an image in RAM. The image can be preloaded or it can be loaded by TPL directly into RAM (e.g. using USB). config TPL_RAM_DEVICE bool "Support booting from preloaded image in RAM" depends on TPL_RAM_SUPPORT help Enable booting of an image already loaded in RAM. The image has to be already in memory when TPL takes over, e.g. loaded by the boot ROM. config TPL_RTC_SUPPORT bool "Support RTC drivers" help Enable RTC (Real-time Clock) support in TPL. 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 TPL build. config TPL_SERIAL_SUPPORT bool "Support serial" select TPL_PRINTF select TPL_STRTO 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_LOAD bool "Support loading from SPI flash" depends on TPL_SPI_FLASH_SUPPORT help Enable support for loading next stage, U-Boot or otherwise, from SPI NOR in U-Boot TPL. config TPL_SPI_SUPPORT bool "Support SPI drivers" help Enable support for using SPI in TPL. See SPL_SPI_SUPPORT for details. config TPL_YMODEM_SUPPORT bool "Support loading using Ymodem" depends on TPL_SERIAL_SUPPORT 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 TPL, with a checksum to ensure correctness. endif # TPL config SPL_AT91_MCK_BYPASS bool "Use external clock signal as a source of main clock for AT91 platforms" depends on ARCH_AT91 default n help Use external 8 to 24 Mhz clock signal as source of main clock instead of an external crystal oscillator. This option disables the internal driving on the XOUT pin. The external source has to provide a stable clock on the XIN pin. If this option is disabled, the SoC expects a crystal oscillator that needs driving on both XIN and XOUT lines. endif # SPL endmenu