summaryrefslogtreecommitdiff
path: root/lib
Commit message (Collapse)AuthorAgeLines
* libfdt: fix fdt_stringlist_search()Masahiro Yamada2016-10-24-1/+1
| | | | | | | | | If fdt_getprop() fails, negative error code should be returned. [ DTC commit: daa75e8fa5942caa8e97931aed3a1ee0b7edd74b ] Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* libfdt: fix fdt_stringlist_count()Masahiro Yamada2016-10-24-1/+1
| | | | | | | | | If fdt_getprop() fails, negative error code should be returned. [ DTC commit: e28eff5b787adb3f461d1653598818b2f1f25a73 ] Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* libfdt: Sync overlay with upstreamMaxime Ripard2016-10-23-73/+129
| | | | | | | | | Now that the overlay code has been merge upstream, update our copy to what's been merged, since a significant number of issues have been fixed during the merge process. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Acked-by: Simon Glass <sjg@chromium.org>
* efi_loader: Rename EFI_RUNTIME_{TEXT, DATA} to __efi_runtime{, _data}Alexander Graf2016-10-19-13/+13
| | | | | | | | | | | Compiler attributes are more commonly __foo style tags rather than big upper case eye sores like EFI_RUNTIME_TEXT. Simon Glass felt quite strongly about this, so this patch converts our existing defines over to more eye friendly ones. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Simon Glass <sjg@chromium.org>
* x86: efi: Add EFI loader support for x86Simon Glass2016-10-19-0/+13
| | | | | | | | | | | | | Add the required pieces to support the EFI loader on x86. Since U-Boot only builds for 32-bit on x86, only a 32-bit EFI application is supported. If a 64-bit kernel must be booted, U-Boot supports this directly using FIT (see doc/uImage.FIT/kernel.its). U-Boot can act as a payload for both 32-bit and 64-bit EFI. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Signed-off-by: Alexander Graf <agraf@suse.de>
* efi: Fix missing EFIAPI specifiersSimon Glass2016-10-19-10/+12
| | | | | | | | | These are missing in some functions. Add them to keep things consistent. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Alexander Graf <agraf@suse.de> Signed-off-by: Alexander Graf <agraf@suse.de>
* smbios: Provide serial numberAlexander Graf2016-10-19-0/+5
| | | | | | | | | | If the system has a valid "serial#" environment variable set (which boards that can find it out programatically set automatically), use that as input for the serial number and UUID fields in the SMBIOS tables. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org>
* efi_loader: Fix efi_install_configuration_tableAlexander Graf2016-10-19-1/+1
| | | | | | | | | | | | So far we were only installing the FDT table and didn't have space to store any other. Hence nobody realized that our efi table allocation was broken in that it didn't set the indicator for the number of tables plus one. This patch fixes it, allowing code to allocate new efi tables. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Simon Glass <sjg@chromium.org>
* smbios: Expose in efi_loader as tableAlexander Graf2016-10-19-2/+41
| | | | | | | | | | | | We can pass SMBIOS easily as EFI configuration table to an EFI payload. This patch adds enablement for that case. While at it, we also enable SMBIOS generation for ARM systems, since they support EFI_LOADER. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org>
* smbios: Generate type 4 on non-x86 systemsAlexander Graf2016-10-19-13/+38
| | | | | | | | | | The type 4 table generation code is very x86 centric today. Refactor things out into the device model cpu class to allow the tables to get generated for other architectures as well. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
* smbios: Allow compilation on 64bit systemsAlexander Graf2016-10-19-8/+8
| | | | | | | | | | | | | | The SMBIOS generation code passes pointers as u32. That causes the compiler to warn on casts to pointers. This patch moves all address pointers to uintptr_t instead. Technically u32 would be enough for the current SMBIOS2 style tables, but we may want to extend the code to SMBIOS3 in the future which is 64bit address capable. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org>
* efi_loader: Expose efi_install_configuration_tableAlexander Graf2016-10-19-9/+13
| | | | | | | | | We want to be able to add configuration table entries from our own code as well as from EFI payload code. Export the boot service function internally too, so that we can reuse it. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Simon Glass <sjg@chromium.org>
* x86: Move smbios generation into arch independent directoryAlexander Graf2016-10-19-0/+303
| | | | | | | | | We will need the SMBIOS generation function on ARM as well going forward, so let's move it into a non arch specific location. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org>
* x86: Move table csum into separate fileAlexander Graf2016-10-19-0/+21
| | | | | | | | | We need the checksum function without all the other table functionality soon, so let's split it out into its own C file. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
* efi_loader: gop: Expose fb when 32bppAlexander Graf2016-10-19-0/+16
| | | | | | | When we're running in 32bpp mode, expose the frame buffer address to our payloads so that Linux efifb can pick it up. Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Allow bouncing for networkAlexander Graf2016-10-19-0/+7
| | | | | | | | | | | | | So far bounce buffers were only used for disk I/O, but network I/O may suffer from the same problem. On platforms that have problems doing DMA on high addresses, let's also bounce outgoing network packets. Incoming ones always already get bounced. This patch fixes EFI PXE boot on ZynqMP for me. Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Allow boards to implement get_time and reset_systemAlexander Graf2016-10-18-11/+91
| | | | | | | | | | | | | | | EFI allows an OS to leverage firmware drivers while the OS is running. In the generic code we so far had to stub those implementations out, because we would need board specific knowledge about MMIO setups for it. However, boards can easily implement those themselves. This patch provides the framework so that a board can implement its own versions of get_time and reset_system which would actually do something useful. While at it we also introduce a simple way for code to reserve MMIO pointers as runtime available. Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Do not leak memory when unlinking a mappingStefan Brüns2016-10-18-2/+5
| | | | | | | | | | As soon as a mapping is unlinked from the list, there are no further references to it, so it should be freed. If it not unlinked, update the start address and length. Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de> Reviewed-by: Alexander Graf <agraf@suse.de> Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Keep memory mapping sorted when splitting an entryStefan Brüns2016-10-18-1/+2
| | | | | | | | | The code assumes sorted mappings in descending address order. When splitting a mapping, insert the new part next to the current mapping. Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de> Reviewed-by: Alexander Graf <agraf@suse.de> Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Readd freed pages to memory poolStefan Brüns2016-10-18-2/+9
| | | | | | | | | | | | | | | | | | | | | | Currently each allocation creates a new mapping. Readding the mapping as free memory (EFI_CONVENTIONAL_MEMORY) potentially allows to hand out an existing mapping, thus limiting the number of mapping descriptors in the memory map. Mitigates a problem with current (4.8rc7) linux kernels when doing an efi_get_memory map, resulting in an infinite loop. Space for the memory map is reserved with allocate_pool (implicitly creating a new mapping) and filled. If there is insufficient slack space (8 entries) in the map, the space is freed and a new round is started, with space for one more entry. As each round increases requirement and allocation by exactly one, there is never enough slack space. (At least 32 entries are allocated, so as long as there are less than 24 entries, there is enough slack). Earlier kernels reserved no slack, and did less allocations, so this problem was not visible. Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de> Reviewed-by: Alexander Graf <agraf@suse.de> Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Track size of pool allocations to allow freeingStefan Brüns2016-10-18-6/+42
| | | | | | | | | | | | | | | | | | | | | | | | | We need a functional free_pool implementation, as otherwise each allocate_pool causes growth of the memory descriptor table. Different to free_pages, free_pool does not provide the size for the to be freed allocation, thus we have to track the size ourselves. As the only EFI requirement for pool allocation is an alignment of 8 bytes, we can keep allocating a range using the page allocator, reserve the first 8 bytes for our bookkeeping and hand out the remainder to the caller. This saves us from having to use any independent data structures for tracking. To simplify the conversion between pool allocations and the corresponding page allocation, we create an auxiliary struct efi_pool_allocation. Given the allocation size free_pool size can handoff freeing the page range, which was indirectly allocated by a call to allocate_pool, to free_pages. Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de> Reviewed-by: Alexander Graf <agraf@suse.de> Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Move efi_allocate_pool implementation to efi_memory.cStefan Brüns2016-10-18-6/+19
| | | | | | | | | | | | | | | | | We currently handle efi_allocate_pool() in our boot time service file. In the following patch, pool allocation will receive additional internal semantics that we should preserve inside efi_memory.c instead. As foundation for those changes, split the function into an externally facing efi_allocate_pool_ext() for use by payloads and an internal helper efi_allocate_pool() in efi_memory.c that handles the actual allocation. While at it, change the magic 0xfff / 12 constants to the more obvious EFI_PAGE_MASK/SHIFT defines. Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de> Reviewed-by: Alexander Graf <agraf@suse.de> Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Fix crash on 32-bit systemsRobin Randhawa2016-10-18-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A type mismatch in the efi_allocate_pool boot service flow causes hazardous memory scribbling on 32-bit systems. This is efi_allocate_pool's prototype: static efi_status_t EFIAPI efi_allocate_pool(int pool_type, unsigned long size, void **buffer); Internally, it invokes efi_allocate_pages as follows: efi_allocate_pages(0, pool_type, (size + 0xfff) >> 12, (void*)buffer); This is efi_allocate_pages' prototype: efi_status_t efi_allocate_pages(int type, int memory_type, unsigned long pages, uint64_t *memory); The problem: efi_allocate_pages does this internally: *memory = addr; This fix in efi_allocate_pool uses a transitional uintptr_t cast to ensure the correct outcome, irrespective of the system's native word size. This was observed when bootefi'ing the EFI instance of FreeBSD's first stage bootstrap (boot1.efi) on a 32-bit ARM platform (Qemu VExpress + Cortex-a9). Signed-off-by: Robin Randhawa <robin.randhawa@arm.com> Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Fix memory map size check to avoid out-of-bounds accessStefan Brüns2016-10-18-1/+2
| | | | | | | | | | | | | | | | | | | | The current efi_get_memory_map() function overwrites the map_size property before reading its value. That way the sanity check whether our memory map fits into the given array always succeeds, potentially overwriting arbitrary payload memory. This patch moves the property update write after its sanity check, so that the check actually verifies the correct value. So far this has not triggered any known bugs, but we're better off safe than sorry. If the buffer is to small, the returned memory_map_size indicates the required size to the caller. Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de> Reviewed-by: Alexander Graf <agraf@suse.de> Signed-off-by: Alexander Graf <agraf@suse.de>
* efi_loader: Update description of internal efi_mem_carve_outStefan Brüns2016-10-18-3/+11
| | | | | | | | | In 74c16acce30bb882ad5951829d8dafef8eea564c the return values where changed, but the description was kept. Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de> Reviewed-by: Alexander Graf <agraf@suse.de> Signed-off-by: Alexander Graf <agraf@suse.de>
* spl: move FDT_FIXUP_PARTITIONS to KconfigHeiko Schocher2016-10-15-0/+9
| | | | | | | Move FDT_FIXUP_PARTITIONS to Kconfig and cleanup existing uses. Signed-off-by: Heiko Schocher <hs@denx.de>
* libfdt: Drop inlining of fdt_path_offset()Simon Glass2016-10-13-0/+5
| | | | | | | The fdt_path_offset() function is not inlined in upstream libfdt. Adjust U-Boot's version to match. Signed-off-by: Simon Glass <sjg@chromium.org>
* libfdt: Sync fdt_for_each_subnode() with upstreamSimon Glass2016-10-13-5/+5
| | | | | | | | | | | The signature for this macro has changed. Bring in the upstream version and adjust U-Boot's usages to suit. Signed-off-by: Simon Glass <sjg@chromium.org> Update to drivers/power/pmic/palmas.c: Signed-off-by: Keerthy <j-keerthy@ti.com> Change-Id: I6cc9021339bfe686f9df21d61a1095ca2b3776e8
* libfdt: Bring in upstream stringlist functionsSimon Glass2016-10-13-41/+65
| | | | | | | | | | | | | | These have now landed upstream. The naming is different and in one case the function signature has changed. Update the code to match. This applies the following upstream commits by Thierry Reding <treding@nvidia.com> : 604e61e fdt: Add functions to retrieve strings 8702bd1 fdt: Add a function to get the index of a string 2218387 fdt: Add a function to count strings Signed-off-by: Simon Glass <sjg@chromium.org>
* libfdt: Sync up with upstreamSimon Glass2016-10-13-10/+10
| | | | | | | | | | | | | | | | This includes small changes to the following functions, from upstream commit 6d1832c: - fdt_get_max_phandle() (upstream commit 84e0e134) - fdt_node_check_compatible (upstream commit 53bf130b) - fdt_setprop_inplace_namelen_partial() to remove useless brackets and use idx instead of index - _fdt_resize_property() to use idx instead of index - _fdt_splice() (upstream commit d4c7c25c) It also includes various typo fixes in libfdt.h Signed-off-by: Simon Glass <sjg@chromium.org>
* libfdt: Fix undefined behaviour in fdt_offset_ptr()David Gibson2016-10-13-6/+7
| | | | | | | | | | | | | Using pointer arithmetic to generate a pointer outside a known object is, technically, undefined behaviour in C. Unfortunately, we were using that in fdt_offset_ptr() to detect overflows. To fix this we need to do our bounds / overflow checking on the offsets before constructing pointers from them. Reported-by: David Binderman <dcb314@hotmail.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Simon Glass <sjg@chromium.org>
* Fix return value in trailing_strtoln()Simon Glass2016-10-11-3/+5
| | | | | | | | | This function should return -1 if there is no trailing integer in the string. Instead it returns 0. Fix it by checking for this condition at the start. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
* spl: saveenv: adding saveenv support in SPLB, Ravi2016-10-08-1/+2
| | | | | | | | | | | | | | | | | | | | | By default saveenv option is not supported for SPL. This patch enable the support for save environment variable for SPL build. 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. Signed-off-by: Ravi Babu <ravibabu@ti.com> Reviewed-by: Simon Glass <sig@chromium.org> change in v1: - dropped SUPPORT, use CONFIG_SPL_SAVEENV - updates the comments in mmc_private.h
* arm: Add return value argument to longjmpAlexander Graf2016-10-08-1/+1
| | | | | | | | | The normal longjmp command allows for a caller to pass the return value of the setjmp() invocation. This patch adds that semantic to the arm implementation of it and adjusts the efi_loader call respectively. Signed-off-by: Alexander Graf <agraf@suse.de> Reviewed-by: Simon Glass <sjg@chromium.org>
* Various, accumulated typos collected from around the tree.Robert P. J. Day2016-10-06-1/+1
| | | | | | | | | | | | | | | | | | | | | Fix various misspellings of: * deprecated * partition * preceding,preceded * preparation * its versus it's * export * existing * scenario * redundant * remaining * value * architecture Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Reviewed-by: Jagan Teki <jteki@openedev.com> Reviewed-by: Stefan Roese <sr@denx.de>
* gunzip: cache-align write buffer memoryClemens Gruber2016-10-06-1/+2
| | | | | | | | | | | | | | When using gzwrite to eMMC on an i.MX6Q board, the following warning occurs repeatedly: CACHE: Misaligned operation at range [4fd63318, 4fe63318] This patch cache-aligns the memory allocation for the gzwrite writebuf, therefore avoiding the misaligned dcache flush and the warning from check_cache_range. Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com> Reviewed-by: Eric Nelson <eric@nelint.com> Reviewed-by: Stefan Agner <stefan.agner@toradex.com>
* treewide: replace #include <asm/errno.h> with <linux/errno.h>Masahiro Yamada2016-09-23-3/+3
| | | | | | | | | | | Now, arch/${ARCH}/include/asm/errno.h and include/linux/errno.h have the same content. (both just wrap <asm-generic/errno.h>) Replace all include directives for <asm/errno.h> with <linux/errno.h>. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> [trini: Fixup include/clk.] Signed-off-by: Tom Rini <trini@konsulko.com>
* libfdt: simplify fdt_del_mem_rsv()Masahiro Yamada2016-09-23-5/+1
| | | | | | | | | | The variable "err" is unneeded. [ Device Tree Compiler commit: 36fd7331fb11276c09a6affc0d8cd4977f2fe100 ] Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Simon Glass <sjg@chromium.org>
* dtoc: Support finding the offset of a propertySimon Glass2016-09-18-0/+3
| | | | | | | | Add a way to find the byte offset of a property within the device tree. This is only supported with the normal libfdt implementation since fdtget does not provide this information. Signed-off-by: Simon Glass <sjg@chromium.org>
* dtoc: Support packing the device treeSimon Glass2016-09-18-0/+1
| | | | | | | | | | After any node/property deletion the device tree can be packed to remove spare space. Add a way to perform this operation. Note that for fdt_fallback, fdtput automatically packs the device tree after deletion, so no action is required here. Signed-off-by: Simon Glass <sjg@chromium.org>
* dtoc: Support deleting device tree propertiesSimon Glass2016-09-18-0/+12
| | | | | | | | Add support for deleting a device tree property. With the fallback implementation this uses fdtput. With libfdt it uses the API call and updates the offsets afterwards. Signed-off-by: Simon Glass <sjg@chromium.org>
* dtoc: Move to using bytearraySimon Glass2016-09-18-0/+8
| | | | | | | | Since we want to be able to change the in-memory device tree using libfdt, use a bytearray instead of a string. This makes interfacing from Python easier. Signed-off-by: Simon Glass <sjg@chromium.org>
* Merge branch 'master' of git://git.denx.de/u-boot-uniphierTom Rini2016-09-18-1/+0
|\
| * usb: uniphier: remove UniPhier xHCI driver and select DM_USBMasahiro Yamada2016-09-14-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This driver has not been converted to Driver Model, and it is an obstacle to migrate other block device drivers. Remove it for now. The UniPhier SoCs already use a DM-based EHCI driver, so now ARCH_UNIPHIER can select DM_USB. These two changes must be done atomically because removing the legacy driver causes a build error. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Marek Vasut <marex@denx.de>
* | Use separate options for TPL supportSimon Glass2016-09-16-2/+7
|/ | | | | | | | | | | | | | | At present TPL uses the same options as SPL support. In a few cases the board config enables or disables the SPL options depending on whether CONFIG_TPL_BUILD is defined. With the move to Kconfig, options are determined for the whole build and (without a hack like an #undef in a header file) cannot be controlled in this way. Create new TPL options for these and update users. This will allow Kconfig conversion to proceed for these boards. Signed-off-by: Simon Glass <sjg@chromium.org>
* efi_loader: provide efi_mem_desc versionMian Yousaf Kaukab2016-09-07-0/+3
| | | | | | | | | | | | Provide version of struct efi_mem_desc in efi_get_memory_map(). EFI_BOOT_SERVICES.GetMemoryMap() in UEFI specification v2.6 defines memory descriptor version to 1. Linux kernel also expects descriptor version to be 1 and prints following warning during boot if its not: Unexpected EFI_MEMORY_DESCRIPTOR version 0 Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@gmail.com>
* x86: efi: payload: Make EFI payload build againBin Meng2016-08-30-3/+3
| | | | | | | | Since commit 73c5c39 "Makefile: Drop unnecessary -dtb suffixes", EFI payload does not build anymore. This fixes the build. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org>
* efi_loader: Fix relocations above 64kb image sizeAlexander Graf2016-08-20-1/+1
| | | | | | | | | | | | | We were truncating the image offset within the target image to 16 bits which again meant that we were potentially overwriting random memory in the lower 16 bits of the image. This patch casts the offset to a more reasonable 32bits. With this applied, I can successfully see Shell.efi assert because it can't find a protocol it expects to be available. Signed-off-by: Alexander Graf <agraf@suse.de>
* tests: Introduce DT overlay testsMaxime Ripard2016-08-20-49/+262
| | | | | | | | | | | | This adds a bunch of unit tests for the "fdt apply" command. They've all been run successfully in the sandbox. However, as you still require an out-of-tree dtc with overlay support, this is disabled by default. Acked-by: Simon Glass <sjg@chromium.org> Acked-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
* cmd: fdt: add fdt overlay application subcommandMaxime Ripard2016-08-20-7/+7
| | | | | | | | | | | | | | | | | | | | | | | The device tree overlays are a good way to deal with user-modifyable boards or boards with some kind of an expansion mechanism where we can easily plug new board in (like the BBB or the raspberry pi). However, so far, the usual mechanism to deal with it was to have in Linux some driver detecting the expansion boards plugged in and then request these overlays using the firmware interface. That works in most cases, but in some cases, you might want to have the overlays applied before the userspace comes in. Either because the new board requires some kind of an early initialization, or because your root filesystem is accessed through that expansion board. The easiest solution in such a case is to simply have the component before Linux applying that overlay, removing all these drawbacks. Reviewed-by: Stefan Agner <stefan@agner.ch> Acked-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> Acked-by: Simon Glass <sjg@chromium.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>