u-boot: load a kernel that's in a ubi volume

Tue Aug 8 03:39:54 AEST 2017

I'm surprised you are putting the kernel in a bare UBI volume.  AFAIK,
U-Boot can load kernels from UBIFS.  Why wouldn't you create a UBIFS
volume for /boot and put the fitImage in there?

On Mon, Aug 7, 2017 at 8:34 AM, anoo <anoo at linux.vnet.ibm.com> wrote:
> On 2017-08-07 02:36, Joel Stanley wrote:
>>
>> On Mon, Aug 7, 2017 at 1:39 PM, anoo <anoo at linux.vnet.ibm.com> wrote:
>>>
>>> Hi Joel,
>>>
>>> Per our discussion, here are the details of what we’re trying to do and
>>> the
>>> things I’ve tried.
>>
>>
>> Thanks. I spent the afternoon attempting to recreate your results.
>>
>>>
>>> Goal: Have u-boot load a kernel that's in a ubi volume.
>>>
>>> 1. Added ubi support to uboot by adding the following macros to
>>> include/configs/ast-g5-ncsi.h temporarily for testing purposes (a new
>>> config
>>> header would probably need to be created for a final implementation):
>>>
>>> | +#define CONFIG_CMD_UBI
>>> | +#define CONFIG_CMD_UBIFS
>>> | +#define CONFIG_RBTREE
>>> | +#define CONFIG_MTD_DEVICE
>>> | +#define CONFIG_MTD_PARTITIONS
>>> | +#define CONFIG_CMD_MTDPARTS
>>> | +#define CONFIG_LZO
>>
>>
>> I replicated this. I noted that this increases the size of the u-boot
>> image a lot:
>>
>> Old size: 232632
>> New size: 358320
>>
>> This is an extra 122kB, or a 54% increase in the u-boot size.
>>
>> It does still fit in the partition we have, which is 384 KB.
>
>
> Definitely something to keep in mind.
>
>>
>>>
>>> 2. Built a romulus image with the above u-boot change plus commit
>>> https://gerrit.openbmc-project.xyz/#/c/5812/ which is the top-most commit
>>> for a set of changes to remove the initramfs and create a flash image
>>> that
>>> builds the kernel and rootsfs into ubi volumes.
>>
>>
>> Why Romulus? Isn't this work being done for Witherspoon?
>
>
> Yeah, this is being done for witherspoon. I've tested with witherspoon as
> well but also Romulus in case there were device tree changes that needed to
> be done that's a smaller system.
>
>>> 3. Used the generated obmc-phosphor-image-romulus.ubi.mtd to boot qemu.
>>
>>
>> What was the Qemu command line you used?
>
>
> After cloning the openbmc/qemu repo and building (using as reference
> https://github.com/openbmc/docs/blob/master/cheatsheet.md#using-qemu):
>
> ./build/arm-softmmu/qemu-system-arm -m 256 -M romulus-bmc -nographic -drive
> file=/<path_to>/obmc-phosphor-image-romulus.ubi.mtd,format=raw,if=mtd -net
> nic -net
> user,hostfwd=:127.0.0.1:2222-:22,hostfwd=:127.0.0.1:2443-:443,hostfwd=:127.0.0.1:2300-:3000,hostname=qemu
>
> For witherspoon, I use the same command, just pointing to a withespoon
> image.
>
>>
>> Can you share a mkfs.ubifs command line that I can use to create a ubi
>> image?
>
>
> You can create a config test file (named ubi.cfg in this example) in a
> directory where you have the kernel fit image fitImage-<system>.bin, ex:
>
> $ cat ubi.cfg
> [kernel0]
> mode=ubi
> image=fitImage-<system>.bin
> vol_type=static
> vol_name=kernel0
> vol_id=0
>
> Then use ubinize command:
> $ ubinize -p 64 -m 1 -o <outputfilename> ubi.cfg
>
> The ubinize command is being added to the openbmc build with this commit:
> https://gerrit.openbmc-project.xyz/#/c/5801/3/meta-phosphor/classes/image_types_phosphor.bbclass
>
> The rwfs is built with:
> "UBIFS_RWFS_CMD = "mkfs.ubifs -r ubifs -c ${FLASH_UBI_RWFS_LEBS} -m
> ${FLASH_PAGE_SIZE} -e ${FLASH_LEB_SIZE}KiB rwfs.ubifs"
>
> Then the ubi image is built with:
> "ubinize -p ${FLASH_PEB_SIZE}KiB -m ${FLASH_PAGE_SIZE} -o ubi-img $cfg"
>
>>
>> When I tried to boot the image I downloaded from the gerrit job, none
>> of the uboot commands you listed worked:
>
>
> An image needs to built with the u-boot changes that enable ubi, since that
> is not in gerrit. You'd need to build an openbmc image with the u-boot
> recipe pointing to a local u-boot repo that has the ubi macros enabled.
>
> I'll pass you in a separate msg the image I have built.
>
>
>>
>> U-Boot 2016.07 (Jul 27 2017 - 21:13:25 +0000)
>>
>>        Watchdog enabled
>> DRAM:  496 MiB
>> 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
>> libfdt fdt_check_header(): FDT_ERR_BADMAGIC
>> Wrong Image Format for bootm command
>> ERROR: can't get kernel image!
>> ast# mtdparts
>> Unknown command 'mtdparts' - try 'help'
>> ast# ubi part kernel0
>> Unknown command 'ubi' - try 'help'
>>
>>
>>>
>>> 4. To be able to use ubi in u-boot, the mtdparts and mtdids variables
>>> need
>>> to be set (reference:
>>> https://fossies.org/linux/qemu/roms/u-boot/doc/README.ubi).
>>>
>>> Here is where I’ve been unable to get u-boot to recognize the existing
>>> mtd.
>>> I’ve tried multiple combinations for mtdids, such as nor0=bmc,
>>> nor0=<addr>.flash, etc etc. But when running “mtdparts” command from
>>> u-boot,
>>> or a ubi command, always get "Device nor0 not found!”. Ex:
>>>
>>> ast# mtdparts
>>> Device nor0 not found!
>>>
>>> ast# ubi part kernel0
>>> Device nor0 not found!
>>> Error initializing mtdparts!
>>>
>>> I’ve also taken a stab at adding the romulus device tree to u-boot to see
>>> if
>>> that may be the reason, by copying from the kernel and adding to u-boot
>>> the
>>> files arch/arm/dts/aspeed-g5.dtsi, aspeed-bmc-opp-flash-layout.dtsi,
>>> aspeed-bmc-opp-romulus.dts, and adding the dts to the Makefile. Also
>>> added a
>>> CONFIG_DEFAULT_DEVICE_TREE macro. This might not be the correct or
>>> complete
>>> way to add the device tree to the openbmc version of u-boot.
>>
>>
>> Can you explain what you were trying to do there?
>
>
> I was trying to add the system device tree to u-boot. The device trees for
> the openbmc systems are defined in the kernel, but they may be required to
> be defined in u-boot for u-boot to find the mtd partitions.
>
>>
>> Cheers,
>>
>> Joel
>
>