Single device tree blob between linux and u-boot

[Cédric Le Goater]

On 10/26/2016 07:22 AM, Joel Stanley wrote:
> Hey Rick,
> 
> On Fri, Oct 14, 2016 at 6:07 AM, Rick Altherr <raltherr at google.com> wrote:
>> I've been working on signed kernel images which depends on building FIT
>> images that include the kernel, initrd, and dtb.  The kernel_fitimage branch
>> of my tree (https://github.com/kc8apf/openbmc) will build an unsigned FIT
>> image by including the dtb specified in the machine config (usually from the
>> kernel).  There are also provisions in there for u-boot being built in two
>> stages so a control dtb that includes the public signing keys can be
>> combined into the final u-boot binary.  From how that is structure, I
>> suspect Maxim is right that there will be some differences between u-boot's
>> dtb and linux's dtb.  That shouldn't be an issue as the u-boot dtb gets
>> built into the u-boot image while the kernel dtb is loaded from the FIT
>> image.
> 
> I finally got around to testing your FIT changes.
> 
> I had to build my own u-boot, as we don't have FIT support enabled. We
> should make sure to add that to your patch series (in fact, we could
> enable it now interdependently of the other changes).
> 
> I created an image like this:
> 
> $ dd if=/dev/zero of=flash-test bs=1M count=32
> $ dd if=/home/joel/dev/u-boot/u-boot.bin of=flash-test conv=notrunc bs=1
> $ dd if=/home/joel/dev/obmc/fit/fitImage-core-image-minimal-initramfs-palmetto.bin
> of=flash-test conv=notrunc bs=1K seek=512
> 
> Here it is booting in Qemu:
> 
> $ qemu-system-arm -m 256M -M palmetto-bmc -nographic -nodefaults -net
> nic -net user,hostfwd=:127.0.0.1:2222-:22,hostname=qemu -serial stdio
> -drive file=~/dev/obmc/flash-test,format=raw,if=mtd

I just included the above in the u-boot wiki. Gavin was asking for it 
for its development. I should extend a bit on the topic but I would
need to check which image to use first. This is all very custom for 
the moment. 

The TODO list needs an update also for the FIT image.

Thanks,

C.


> 
> U-Boot 2016.11-rc2-02954-g9f82ceb7118d (Oct 26 2016 - 15:36:23 +1030)
> 
> SOC : AST2400-A0
> RST : Power On
> PLL :     24 MHz
> CPU :    384 MHz
> MEM :      0 MHz, EEC:Disable
> VGA :    16 MiB
> DRAM :   init by SOC
> Model: Palmetto BMC
> DRAM:  240 MiB
> WARNING: Caches not enabled
> Flash: 32 MiB
> *** Warning - bad CRC, using default environment
> 
> In:    serial
> Out:   serial
> Err:   serial
> Net:   aspeednic#0
> Error: aspeednic#0 address not set.
> 
> Hit any key to stop autoboot:  0
> ast# bootm 0x80000
> ## Loading kernel from FIT Image at 00080000 ...
>    Using 'conf at 1' configuration
>    Trying 'kernel at 1' kernel subimage
>      Description:  Linux kernel
>      Type:         Kernel Image
>      Compression:  uncompressed
>      Data Start:   0x00080124
>      Data Size:    1511416 Bytes = 1.4 MiB
>      Architecture: ARM
>      OS:           Linux
>      Load Address: 0x40008000
>      Entry Point:  0x40008000
>      Hash algo:    sha1
>      Hash value:   1ab23fabb23234a21cd80651cd3c96a9b58a9e4c
>    Verifying Hash Integrity ... sha1+ OK
> ## Loading ramdisk from FIT Image at 00080000 ...
>    Using 'conf at 1' configuration
>    Trying 'ramdisk at 1' ramdisk subimage
>      Description:  ramdisk image
>      Type:         RAMDisk Image
>      Compression:  uncompressed
>      Data Start:   0x001f62b8
>      Data Size:    4724736 Bytes = 4.5 MiB
>      Architecture: ARM
>      OS:           Linux
>      Load Address: unavailable
>      Entry Point:  unavailable
>      Hash algo:    sha1
>      Hash value:   202c90e945a883ba8ff73fa4e197a17d6a9ce9f4
>    Verifying Hash Integrity ... sha1+ OK
> ## Loading fdt from FIT Image at 00080000 ...
>    Using 'conf at 1' configuration
>    Trying 'fdt at 1' fdt subimage
>      Description:  Flattened Device Tree blob
>      Type:         Flat Device Tree
>      Compression:  uncompressed
>      Data Start:   0x001f1210
>      Data Size:    20463 Bytes = 20 KiB
>      Architecture: ARM
>      Hash algo:    sha1
>      Hash value:   63054f0970e89a70a15d1faac53fe9544a83e2e5
>    Verifying Hash Integrity ... sha1+ OK
>    Booting using the fdt blob at 0x1f1210
>    Loading Kernel Image ... OK
>    Loading Ramdisk to 4e700000, end 4eb81800 ... OK
>    Loading Ramdisk to 4e27e000, end 4e6ff800 ... OK
>    Loading Device Tree to 4e276000, end 4e27dfee ... OK
> 
> Starting kernel ...
> 
> Uncompressing Linux... done, booting the kernel.
> Booting Linux on physical CPU 0x0
> Linux version 4.7.10-32ede9ab3deda73c484c4e2d372863bb73d0f7e0
> (joel at ka3.ozlabs.ibm.com) (gcc version 5.3.0 (GCC) ) #1 Wed Oct 26
> 13:57:23 AEDT 2016
> CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=00093177
> CPU: VIVT data cache, VIVT instruction cache
> Machine model: Palmetto BMC
> Memory policy: Data cache writeback
> SOC Rev: 02000303
> Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 60960
> Kernel command line: console=ttyS4,115200n8 root=/dev/ram rw
> 
> 
> Looks good!
> 
> Cheers,
> 
> Joel
>