Hello I have been out of office for the Christmas/New Year period, so please forgive a delay in answering. On Sat, Jan 12, 2019 at 6:19 PM Pham, Phong wrote: > > > Hi, > > > > I have a Linux newbie filesystem question. > > > > On Linux command line: mount -t yaffs2 /dev/ram2 /mnt/mtd > > > > Where ram2 is a block device with major number RAMDISK_MAJOR, then > yaffs2_mount() is executed. (The consequence is failure but I am not > interested in the failure.) > > > > However, when a > > mount -t yaffs2 /dev/mydevice /mnt/mtd > > > > where mydevice is a block device with major number MTD_BLOCK_MAJOR, then > yaffs2_mount() is not executed. Linux couldn’t find an entry in the > bdev_map->probe[MTD_BLOCK_MAJOR] (in genhd.c). Is this because I don’t > have a MTD Chip Driver installed for YAFFS2 MTD “user” module? (I > currently do not have the driver yet; just experimenting right now.) > The mtd "block devices" are a bit of a cheat way to pass access to the mtd drivers to a flash file system. Yaffs needs flash drivers, not generic block drivers. Hence, Yaffs will only succeed mounting an mtd block device. If you want to experiment on a system that does not have flash memory and an mtd block device, then you can use nandsim instead. This makes a fake mtd block driver that is backed by memory, but still provides all the mtd access functions. For an example of how to do this, have a look in the yaffs2/linux-tests directory at the initnandsim script. > > During initialization, I do see init_mtdblock() is invoked and > major_names[MTD_BLOCK_MAJOR] is initialized (register_blkdev() is invoked), > but bdev_map->probe[MTD_BLOCK_MAJOR] is not initialized. > > > > Advise pls., > > Phong. > > Notice: This e-mail and any files transmitted with it may contain Data > Device Corporation's and its subsidiaries privileged and proprietary > information. It is intended solely for the use of the individual or entity > to whom it is addressed. If you are not the named recipient of this > transmission, any disclosure, copying, distribution or reliance on the > contents of this message is prohibited. If you received this e-mail in > error, please destroy it and any attached files and notify me immediately. > > Click Here to view our > privacy statement. > _______________________________________________ > yaffs mailing list > yaffs@stoneboat.aleph1.co.uk > http://stoneboat.aleph1.co.uk/cgi-bin/mailman/listinfo/yaffs >