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diff --git a/doc/usage/fit/howto.rst b/doc/usage/fit/howto.rst new file mode 100644 index 0000000..c933703 --- /dev/null +++ b/doc/usage/fit/howto.rst @@ -0,0 +1,419 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +How to use images in the new image format +========================================= + +Overview +-------- + +The new uImage format allows more flexibility in handling images of various +types (kernel, ramdisk, etc.), it also enhances integrity protection of images +with sha1 and md5 checksums. + +Two auxiliary tools are needed on the development host system in order to +create an uImage in the new format: mkimage and dtc, although only one +(mkimage) is invoked directly. dtc is called from within mkimage and operates +behind the scenes, but needs to be present in the $PATH nevertheless. It is +important that the dtc used has support for binary includes -- refer to:: + + git://git.kernel.org/pub/scm/utils/dtc/dtc.git + +for its latest version. mkimage (together with dtc) takes as input +an image source file, which describes the contents of the image and defines +its various properties used during booting. By convention, image source file +has the ".its" extension, also, the details of its format are given in +doc/uImage.FIT/source_file_format.txt. The actual data that is to be included in +the uImage (kernel, ramdisk, etc.) is specified in the image source file in the +form of paths to appropriate data files. The outcome of the image creation +process is a binary file (by convention with the ".itb" extension) that +contains all the referenced data (kernel, ramdisk, etc.) and other information +needed by U-Boot to handle the uImage properly. The uImage file is then +transferred to the target (e.g., via tftp) and booted using the bootm command. + +To summarize the prerequisites needed for new uImage creation: + +- mkimage +- dtc (with support for binary includes) +- image source file (`*.its`) +- image data file(s) + + +Here's a graphical overview of the image creation and booting process:: + + image source file mkimage + dtc transfer to target + + ---------------> image file --------------------> bootm + image data file(s) + +SPL usage +--------- + +The SPL can make use of the new image format as well, this traditionally +is used to ship multiple device tree files within one image. Code in the SPL +will choose the one matching the current board and append this to the +U-Boot proper binary to be automatically used up by it. +Aside from U-Boot proper and one device tree blob the SPL can load multiple, +arbitrary image files as well. These binaries should be specified in their +own subnode under the /images node, which should then be referenced from one or +multiple /configurations subnodes. The required images must be enumerated in +the "loadables" property as a list of strings. + +If a platform specific image source file (.its) is shipped with the U-Boot +source, it can be specified using the CONFIG_SPL_FIT_SOURCE Kconfig symbol. +In this case it will be automatically used by U-Boot's Makefile to generate +the image. +If a static source file is not flexible enough, CONFIG_SPL_FIT_GENERATOR +can point to a script which generates this image source file during +the build process. It gets passed a list of device tree files (taken from the +CONFIG_OF_LIST symbol). + +The SPL also records to a DT all additional images (called loadables) which are +loaded. The information about loadables locations is passed via the DT node with +fit-images name. + +Finally, if there are multiple xPL phases (e.g. SPL, VPL), images can be marked +as intended for a particular phase using the 'phase' property. For example, if +fit_image_load() is called with image_ph(IH_PHASE_SPL, IH_TYPE_FIRMWARE), then +only the image listed into the "firmware" property where phase is set to "spl" +will be loaded. + +Loadables Example +----------------- +Consider the following case for an ARM64 platform where U-Boot runs in EL2 +started by ATF where SPL is loading U-Boot (as loadables) and ATF (as firmware). + +:: + + /dts-v1/; + + / { + description = "Configuration to load ATF before U-Boot"; + + images { + uboot { + description = "U-Boot (64-bit)"; + data = /incbin/("u-boot-nodtb.bin"); + type = "firmware"; + os = "u-boot"; + arch = "arm64"; + compression = "none"; + load = <0x8 0x8000000>; + entry = <0x8 0x8000000>; + hash { + algo = "md5"; + }; + }; + atf { + description = "ARM Trusted Firmware"; + data = /incbin/("bl31.bin"); + type = "firmware"; + os = "arm-trusted-firmware"; + arch = "arm64"; + compression = "none"; + load = <0xfffea000>; + entry = <0xfffea000>; + hash { + algo = "md5"; + }; + }; + fdt_1 { + description = "zynqmp-zcu102-revA"; + data = /incbin/("arch/arm/dts/zynqmp-zcu102-revA.dtb"); + type = "flat_dt"; + arch = "arm64"; + compression = "none"; + load = <0x100000>; + hash { + algo = "md5"; + }; + }; + }; + configurations { + default = "config_1"; + + config_1 { + description = "zynqmp-zcu102-revA"; + firmware = "atf"; + loadables = "uboot"; + fdt = "fdt_1"; + }; + }; + }; + +In this case the SPL records via fit-images DT node the information about +loadables U-Boot image:: + + ZynqMP> fdt addr $fdtcontroladdr + ZynqMP> fdt print /fit-images + fit-images { + uboot { + os = "u-boot"; + type = "firmware"; + size = <0x001017c8>; + entry = <0x00000008 0x08000000>; + load = <0x00000008 0x08000000>; + }; + }; + +As you can see entry and load properties are 64bit wide to support loading +images above 4GB (in past entry and load properties where just 32bit). + + +Example 1 -- old-style (non-FDT) kernel booting +----------------------------------------------- + +Consider a simple scenario, where a PPC Linux kernel built from sources on the +development host is to be booted old-style (non-FDT) by U-Boot on an embedded +target. Assume that the outcome of the build is vmlinux.bin.gz, a file which +contains a gzip-compressed PPC Linux kernel (the only data file in this case). +The uImage can be produced using the image source file +doc/uImage.FIT/kernel.its (note that kernel.its assumes that vmlinux.bin.gz is +in the current working directory; if desired, an alternative path can be +specified in the kernel.its file). Here's how to create the image and inspect +its contents: + +[on the host system]:: + + $ mkimage -f kernel.its kernel.itb + DTC: dts->dtb on file "kernel.its" + $ + $ mkimage -l kernel.itb + FIT description: Simple image with single Linux kernel + Created: Tue Mar 11 17:26:15 2008 + Image 0 (kernel) + Description: Vanilla Linux kernel + Type: Kernel Image + Compression: gzip compressed + Data Size: 943347 Bytes = 921.24 kB = 0.90 MB + Architecture: PowerPC + OS: Linux + Load Address: 0x00000000 + Entry Point: 0x00000000 + Hash algo: crc32 + Hash value: 2ae2bb40 + Hash algo: sha1 + Hash value: 3c200f34e2c226ddc789240cca0c59fc54a67cf4 + Default Configuration: 'config-1' + Configuration 0 (config-1) + Description: Boot Linux kernel + Kernel: kernel + + +The resulting image file kernel.itb can be now transferred to the target, +inspected and booted (note that first three U-Boot commands below are shown +for completeness -- they are part of the standard booting procedure and not +specific to the new image format). + +[on the target system]:: + + => print nfsargs + nfsargs=setenv bootargs root=/dev/nfs rw nfsroot=${serverip}:${rootpath} + => print addip + addip=setenv bootargs ${bootargs} ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}:${netdev}:off panic=1 + => run nfsargs addip + => tftp 900000 /path/to/tftp/location/kernel.itb + Using FEC device + TFTP from server 192.168.1.1; our IP address is 192.168.160.5 + Filename '/path/to/tftp/location/kernel.itb'. + Load address: 0x900000 + Loading: ################################################################# + done + Bytes transferred = 944464 (e6950 hex) + => iminfo + + ## Checking Image at 00900000 ... + FIT image found + FIT description: Simple image with single Linux kernel + Created: 2008-03-11 16:26:15 UTC + Image 0 (kernel) + Description: Vanilla Linux kernel + Type: Kernel Image + Compression: gzip compressed + Data Start: 0x009000e0 + Data Size: 943347 Bytes = 921.2 kB + Architecture: PowerPC + OS: Linux + Load Address: 0x00000000 + Entry Point: 0x00000000 + Hash algo: crc32 + Hash value: 2ae2bb40 + Hash algo: sha1 + Hash value: 3c200f34e2c226ddc789240cca0c59fc54a67cf4 + Default Configuration: 'config-1' + Configuration 0 (config-1) + Description: Boot Linux kernel + Kernel: kernel + + => bootm + ## Booting kernel from FIT Image at 00900000 ... + Using 'config-1' configuration + Trying 'kernel' kernel subimage + Description: Vanilla Linux kernel + Type: Kernel Image + Compression: gzip compressed + Data Start: 0x009000e0 + Data Size: 943347 Bytes = 921.2 kB + Architecture: PowerPC + OS: Linux + Load Address: 0x00000000 + Entry Point: 0x00000000 + Hash algo: crc32 + Hash value: 2ae2bb40 + Hash algo: sha1 + Hash value: 3c200f34e2c226ddc789240cca0c59fc54a67cf4 + Verifying Hash Integrity ... crc32+ sha1+ OK + Uncompressing Kernel Image ... OK + Memory BAT mapping: BAT2=256Mb, BAT3=0Mb, residual: 0Mb + Linux version 2.4.25 (m8@hekate) (gcc version 4.0.0 (DENX ELDK 4.0 4.0.0)) #2 czw lip 5 17:56:18 CEST 2007 + On node 0 totalpages: 65536 + zone(0): 65536 pages. + zone(1): 0 pages. + zone(2): 0 pages. + Kernel command line: root=/dev/nfs rw nfsroot=192.168.1.1:/opt/eldk-4.1/ppc_6xx ip=192.168.160.5:192.168.1.1::255.255.0.0:lite5200b:eth0:off panic=1 + Calibrating delay loop... 307.20 BogoMIPS + + +Example 2 -- new-style (FDT) kernel booting +------------------------------------------- + +Consider another simple scenario, where a PPC Linux kernel is to be booted +new-style, i.e., with a FDT blob. In this case there are two prerequisite data +files: vmlinux.bin.gz (Linux kernel) and target.dtb (FDT blob). The uImage can +be produced using image source file doc/uImage.FIT/kernel_fdt.its like this +(note again, that both prerequisite data files are assumed to be present in +the current working directory -- image source file kernel_fdt.its can be +modified to take the files from some other location if needed): + +[on the host system]:: + + $ mkimage -f kernel_fdt.its kernel_fdt.itb + DTC: dts->dtb on file "kernel_fdt.its" + $ + $ mkimage -l kernel_fdt.itb + FIT description: Simple image with single Linux kernel and FDT blob + Created: Tue Mar 11 16:29:22 2008 + Image 0 (kernel) + Description: Vanilla Linux kernel + Type: Kernel Image + Compression: gzip compressed + Data Size: 1092037 Bytes = 1066.44 kB = 1.04 MB + Architecture: PowerPC + OS: Linux + Load Address: 0x00000000 + Entry Point: 0x00000000 + Hash algo: crc32 + Hash value: 2c0cc807 + Hash algo: sha1 + Hash value: 264b59935470e42c418744f83935d44cdf59a3bb + Image 1 (fdt-1) + Description: Flattened Device Tree blob + Type: Flat Device Tree + Compression: uncompressed + Data Size: 16384 Bytes = 16.00 kB = 0.02 MB + Architecture: PowerPC + Hash algo: crc32 + Hash value: 0d655d71 + Hash algo: sha1 + Hash value: 25ab4e15cd4b8a5144610394560d9c318ce52def + Default Configuration: 'conf-1' + Configuration 0 (conf-1) + Description: Boot Linux kernel with FDT blob + Kernel: kernel + FDT: fdt-1 + + +The resulting image file kernel_fdt.itb can be now transferred to the target, +inspected and booted: + +[on the target system]:: + + => tftp 900000 /path/to/tftp/location/kernel_fdt.itb + Using FEC device + TFTP from server 192.168.1.1; our IP address is 192.168.160.5 + Filename '/path/to/tftp/location/kernel_fdt.itb'. + Load address: 0x900000 + Loading: ################################################################# + ########### + done + Bytes transferred = 1109776 (10ef10 hex) + => iminfo + + ## Checking Image at 00900000 ... + FIT image found + FIT description: Simple image with single Linux kernel and FDT blob + Created: 2008-03-11 15:29:22 UTC + Image 0 (kernel) + Description: Vanilla Linux kernel + Type: Kernel Image + Compression: gzip compressed + Data Start: 0x009000ec + Data Size: 1092037 Bytes = 1 MB + Architecture: PowerPC + OS: Linux + Load Address: 0x00000000 + Entry Point: 0x00000000 + Hash algo: crc32 + Hash value: 2c0cc807 + Hash algo: sha1 + Hash value: 264b59935470e42c418744f83935d44cdf59a3bb + Image 1 (fdt-1) + Description: Flattened Device Tree blob + Type: Flat Device Tree + Compression: uncompressed + Data Start: 0x00a0abdc + Data Size: 16384 Bytes = 16 kB + Architecture: PowerPC + Hash algo: crc32 + Hash value: 0d655d71 + Hash algo: sha1 + Hash value: 25ab4e15cd4b8a5144610394560d9c318ce52def + Default Configuration: 'conf-1' + Configuration 0 (conf-1) + Description: Boot Linux kernel with FDT blob + Kernel: kernel + FDT: fdt-1 + => bootm + ## Booting kernel from FIT Image at 00900000 ... + Using 'conf-1' configuration + Trying 'kernel' kernel subimage + Description: Vanilla Linux kernel + Type: Kernel Image + Compression: gzip compressed + Data Start: 0x009000ec + Data Size: 1092037 Bytes = 1 MB + Architecture: PowerPC + OS: Linux + Load Address: 0x00000000 + Entry Point: 0x00000000 + Hash algo: crc32 + Hash value: 2c0cc807 + Hash algo: sha1 + Hash value: 264b59935470e42c418744f83935d44cdf59a3bb + Verifying Hash Integrity ... crc32+ sha1+ OK + Uncompressing Kernel Image ... OK + ## Flattened Device Tree from FIT Image at 00900000 + Using 'conf-1' configuration + Trying 'fdt-1' FDT blob subimage + Description: Flattened Device Tree blob + Type: Flat Device Tree + Compression: uncompressed + Data Start: 0x00a0abdc + Data Size: 16384 Bytes = 16 kB + Architecture: PowerPC + Hash algo: crc32 + Hash value: 0d655d71 + Hash algo: sha1 + Hash value: 25ab4e15cd4b8a5144610394560d9c318ce52def + Verifying Hash Integrity ... crc32+ sha1+ OK + Booting using the fdt blob at 0xa0abdc + Loading Device Tree to 007fc000, end 007fffff ... OK + [ 0.000000] Using lite5200 machine description + [ 0.000000] Linux version 2.6.24-rc6-gaebecdfc (m8@hekate) (gcc version 4.0.0 (DENX ELDK 4.1 4.0.0)) #1 Sat Jan 12 15:38:48 CET 2008 + + +Example 3 -- advanced booting +----------------------------- + +Refer to :doc:`multi` for an image source file that allows more +sophisticated booting scenarios (multiple kernels, ramdisks and fdt blobs). + +.. sectionauthor:: Bartlomiej Sieka <tur@semihalf.com> |