Re: Block based OTA update needs mtdblock

From: Richard Weinberger <richard@nod.at>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Pintu Agarwal <pintu.ping@gmail.com>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	 linux-mtd <linux-mtd@lists.infradead.org>,
	 chengzhihao1 <chengzhihao1@huawei.com>,
	 linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Block based OTA update needs mtdblock
Date: Tue, 3 Dec 2024 17:08:14 +0100 (CET)	[thread overview]
Message-ID: <342000380.28770675.1733242094522.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <87ldww4zrx.fsf@bootlin.com>

----- Ursprüngliche Mail -----
> Von: "Miquel Raynal" <miquel.raynal@bootlin.com>
> An: "Pintu Agarwal" <pintu.ping@gmail.com>
> CC: "richard" <richard@nod.at>, "Vignesh Raghavendra" <vigneshr@ti.com>, "linux-mtd" <linux-mtd@lists.infradead.org>,
> "chengzhihao1" <chengzhihao1@huawei.com>, "linux-kernel" <linux-kernel@vger.kernel.org>
> Gesendet: Dienstag, 3. Dezember 2024 15:17:06
> Betreff: Re: Block based OTA update needs mtdblock

> Hello,
> 
> On 20/11/2024 at 12:52:57 +0530, Pintu Agarwal <pintu.ping@gmail.com> wrote:
> 
>> Hi,
>>
>> On Mon, 4 Nov 2024 at 21:31, Pintu Agarwal <pintu.ping@gmail.com> wrote:
>>>
>>> Hi All,
>>>
>>> For one of our automotive products we have the following configuration:
>>> QC chipset, arm64, Kernel-5.15, NAND Flash 1GB, A/B system, UBI
>>> volumes (squashfs, ubifs), DM-verity for rootfs (squashfs), simple
>>> busybox platform.
>>>
>>> For OTA updates we have a strong dependency with MTD_BLOCK.
>>>
>>> Till now, we were using ubiblock for mounting squashfs volumes and
>>> completely got rid of mtd_block by configuring it as a loadable
>>> module.
>>> But, we also need to support OTA updates (Full, Incremental) on A/B
>>> volumes using the same Android OTA framework.
>>> https://source.android.com/docs/core/ota/nonab/block
>>>
>>> OTA update will be applied to the B (inactive) partition.
>>> OTA updates prefer block based update over file based especially for
>>> dm-verity enabled devices.
>>>
>>> Now, the problem is, on MTD we only have 2 options for block based
>>> updates; ubi_block or mtd_block.
>>> We cannot use ubiblock for OTA updates as it is read only.
>>> For full update volume, we can use "ubiupdatevol" interface to
>>> completely replace the volume content, but for partial or incremental
>>> update we need to update only specific blocks and not entire
>>> partitions.
>>> Thus, we have to use the MTD_BLOCK (/dev/mtdblock) interface to
>>> support block based OTA updates on UBI volumes.
>>> Thus, during ota updates (only) we need to install the mtdblock
>>> module, perform the update and then uninstall the module.
>>>
>>> That means, we cannot completely get rid of MTD_BLOCK from our product
>>> especially for OTA use cases.
>>>
>>> Is this the only way, or do we have any other option to support OTA
>>> updates over UBI volumes ?
>>>
>> Restarting this thread again...
>> Any further comment on this ?
>>
>> Did anybody used block based OTA update NAND A/B system without using
>> mtd_block ?
> 
> Not on my side, it is actually a good question. Richard, any ideas?

What about using ubiupdatevol?

Thanks,
//richard

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