| How to use images in the new image format |
| ========================================= |
| |
| Author: Bartlomiej Sieka <tur@semihalf.com> |
| |
| |
| 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/uImage.FIT/multi.its for an image source file that allows more |
| sophisticated booting scenarios (multiple kernels, ramdisks and fdt blobs). |