uboot images

[kowalski100]

We need uboot and openSBI image from the following version:

https://github.com/polarfire-soc/meta-polarfire-soc-yocto-bsp/releases/tag/v2021.04

1. Is it possible to extract individual artifacts out of the above .wic file?
2. Second, is it possible to burn only uboot and openSBI via USBImage software mentioned.

[griffini]

Hi @kowalski100,

1. Yes, it is possible to extract the artifacts from the wic file, at least on Linux. The flow to do this has a couple of steps. First, create a loopback (virtual block) device using the wic file...

$ sudo losetup -vfP --show core-image-minimal-dev.wic

This will print out the new loop device number to the console, e.g., something like ...

/dev/loop31

Extract the HSS payload.bin from this... It is usually partition 2 -- you can use fdisk /dev/loopXX to be sure, where //dev/loopXX corresponds to the loop device number previously printed to the console.

For the rest of this example, I'm going to use /dev/loop31, but make sure to substitute the correct loop device for your system.

$ sudo fdisk -l /dev/loop31
Disk /dev/loop31: 6.48 GiB, 6947813376 bytes, 13569948 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: CA845C1B-DFCA-4AB7-8686-DCB4827DC157

Device Start End Sectors Size Type
/dev/loop31p1 8192 47685 39494 19.3M Microsoft basic data
/dev/loop31p2 47686 64069 16384 8M BIOS boot
/dev/loop31p3 65536 13569913 13504378 6.4G Linux filesystem

You can see from the above fdisk output that /dev/loop31p2 is the "BIOS boot" partition type used by the HSS to find the payload.bin.

Next, copy payload.bin from the loopback partition to a file, and delete the loopback device (as we're finished with it).

$ sudo dd if=/dev/loop31p2 of=payload.bin
$ sudo losetup -d /dev/loop31

The resulting payload.bin file will be the size of partition /dev/loop31p2, so it could be longer than the original payload.bin -- but you mightn't really care about the stuff at the end... If you do, follow the next few steps...

OPTIONAL: Use the payload generator -d flag to make sure that it is a payload.bin.:

$ hss-payload-generator -d payload.bin
Hart Software Service formatted boot image generator v0.99.26
Copyright (c) 2021 Microchip FPGA Embedded Systems Solutions.

opening >>payload.bin<<
magic: 0xb007c0de
headerLength: 0x678
chunkTableOffset: 0x610
ziChunkTableOffset: 0x660
name[0]: >>u-boot.bin<<
entryPoint[0]: 0x80200000
privMode[0]: 1 (PRV_S)
flags[0]: 0
firstChunk[0] 0
lastChunk[0] 0
numChunks[0] 1
name[1]: >><<
entryPoint[1]: 0x80200000
privMode[1]: 1 (PRV_S)
flags[1]: 0
firstChunk[1] 0
lastChunk[1] 0
numChunks[1] 0
name[2]: >><<
entryPoint[2]: 0x80200000
privMode[2]: 1 (PRV_S)
flags[2]: 0
firstChunk[2] 0
lastChunk[2] 0
numChunks[2] 0
name[3]: >><<
entryPoint[3]: 0x80200000
privMode[3]: 1 (PRV_S)
flags[3]: 0
firstChunk[3] 0
lastChunk[3] 0
numChunks[3] 0
set_name >>PolarFire-SoC-HSS::U-Boot<<
bootImageLength: 497976
headerCrc: 0x6b5bf69b
- 1 chunk found for owner 1
Boot Chunks: total of 2 chunks found
ZI Chunks: total of 1 chunk found

OPTIONAL: Truncate the payload.bin size: - In this case, the HSS Payload Generator tool has told us that the payload.bin file is 496976 bytes long (bootImageLength: 497976 above) so we can truncate the file we created using dd...

$ truncate -s 497976 payload.bin

2. Would you mind explaining what you are trying to achieve here? You need the HSS to at least train DDR and perform some PolarFire SoC low-level setup before running U-Boot or OpenSBI...

[kowalski100]

Hi @griffini,

Thank you so much for taking time to provide such a detail answer. I was able to extract payload.bin file. I have following followup questions:

1. What's the difference b/w payload.bin and uboot.img?
2. Is it possible to load standalone payload.bin (ONLY) on onboard eMMC and and instruct HSS to load it or we have to follow the sd-card boot method? Actually we don't want linux kernel. we want flow till uboot. I guess the .wic file provide complete file system details that are burned on eMMC. we want to place only u-boot there. This page has information on how to write complete image not only payload.bin file which is our requirements. similarly is it possible to burn/copy only payload.bin file to sd-card?
3. Is OpenSBL part of payload.bin or HSS, how we can deploy it?

Sure. We want our software to run on icicle after uboot instead of linux kernel. So we need flow till uboot.

[griffini]

Regarding your questions:

1. payload.bin contains the U-Boot binary, plus some additional formatting/header information needed by the HSS. The file can contan any application image you want - or indeed, multiple images, and describes how they are assigned to the various U54 harts. I don't know what uboot.img is (in the context of PolarFire SoC) -- where was this file?

2. Yes, you can use a standalone payload.bin that you program to the eMMC and have the HSS load it. By default, the HSS with search for a partition on the eMMC (if no SDCard is inserted) with a GUID of 21686148-6449-6E6F-744E-656564454649 and if it finds one attempt to load a payload.bin image from it.

   If it doesn't find a BIOS boot partition, it will also search the start of the eMMC (sector zero) for its payload.bin image.

   You can follow the same flow to write the payload.bin file directly instead of the full .wic image if you do not need Linux.

3. Yes, OpenSBI is provided as part of the HSS. The binary file you build as part of your custom payload.bin file will be started using OpenSBI.

See https://github.com/polarfire-soc/hart-software-services/tree/master/tools/hss-payload-generator#readme for more information on how to create a payload.bin file that is bootable via the HSS.

What you describe is simpler than using Linux, so your flow will be probably something like:

1. Create a custom application (maybe .bin or .elf)
2. Use the hss-payload-generator with your .bin or .elf to create a payload.bin file
3. Use the HSS USBDMSC command to program the payload.bin directly to the eMMC
4. Reboot and let the HSS boot your payload.bin

[kowalski100]

@griffini Thank you so much for the detail answer.