Re: [PATCH 0/5] Extends block2mtd and ubi drivers

From: Richard Weinberger <richard@nod.at>
To: "Pali Rohár" <pali.rohar@gmail.com>,
	"Joern Engel" <joern@lazybastard.org>,
	"David Woodhouse" <dwmw2@infradead.org>,
	"Brian Norris" <computersforpeace@gmail.com>,
	"Boris Brezillon" <boris.brezillon@free-electrons.com>,
	"Marek Vasut" <marek.vasut@gmail.com>,
	"Cyrille Pitchen" <cyrille.pitchen@atmel.com>,
	"Artem Bityutskiy" <dedekind1@gmail.com>
Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/5] Extends block2mtd and ubi drivers
Date: Fri, 2 Jun 2017 18:17:06 +0200	[thread overview]
Message-ID: <cf1d3cae-885c-39dd-f118-c2a0d9682c94@nod.at> (raw)
In-Reply-To: <1496418222-23483-1-git-send-email-pali.rohar@gmail.com>

Pali,

Am 02.06.2017 um 17:43 schrieb Pali Rohár:
> This patch series extends block2mtd and ubi drivers to better handle
> read-only devices and allow to load UBI image from local file which was
> created for nand device.
> 
> Tested for Nokia N900 with Maemo 5 rootfs ubifs image
> (rootfs_RX-51_2009SE_21.2011.38-1_PR_MR0) which has erase size 128k,
> write size 2k and nand subpage shift 2.

What is the use case behind this series?

Did you see my nandsim rework some time ago?
http://lists.infradead.org/pipermail/linux-mtd/2016-September/069422.html
If you need a way to load files/nanddumps as NAND devices, this should be a good
starting point.
This reminds me that I need to revive that series. :-)

> $ losetup -r /dev/loop0 rootfs_RX-51_2009SE_21.2011.38-1_PR_MR0.ubifs
> $ echo -n /dev/loop0,131072,2048,2 > /sys/module/block2mtd/parameters/block2mtd
> $ ubiattach -p /dev/mtd0
> $ mount /dev/ubi0_0 /mnt/ubi -t ubifs
> ...
> $ umount /dev/ubi0_0
> $ ubidetach -p /dev/mtd0
> $ echo -n del=/dev/loop0 > /sys/module/block2mtd/parameters/block2mtd
> $ losetup -d /dev/loop0

The module-parameter interface is odd. IMHO we should not extend it.

Thanks,
//richard