[uClinux-dev] JFFS and blkmem

David Beamonte dbeamonte at intelnet.es
Mon Nov 5 04:58:19 EST 2001


Changing MTD block major number from 31 to (i.e.) 42 makes the kernel 
register the MTD device properly (mtdchar and mtdblock appear in 
/proc/devices), but when trying to acces to the /dev/mtd0 or 
/dev/mtdblock0 I get the error:

    /dev/mtdblock0: no such device

with /dev/mtdblock0 defined as a block device whose major is 42 and minor 0.
The same happens with mtd0 (major=90, minor=0).

Besides, JFFS always tries to mount over a device with the major number 
defined in BLKMEM and I don't know how to change that...


Thuys, Michiel wrote:

>You can use them at the same time, but then either MTD or blkmem must
>have another major number. JFFS can only work with MTD.
>
>Michiel
>
>-----Original Message-----
>From: David Beamonte [mailto:dbeamonte at intelnet.es]
>Sent: woensdag 31 oktober 2001 18:17
>To: uClinux-dev
>Subject: [uClinux-dev] JFFS and blkmem
>
>
>Hi,
>
>I'm using blkmem to read/write on my flash device. I have 8 arenas 
>defined, and want to use one of them with JFFS. In order to have JFFS 
>support, MTD must be enabled, but if blkmem is enabled, MTD can't 
>allocate its major number. Can I use blkmem and MTD at the same time? 
>Can JFFS be mounted on a blkmem device as I would like to?
>
>When booting, the kernel gives the following message:
>...
>Blkmem copyright 1998,1999 D. Jeff 
>Dionne                                      
>Blkmem copyright 1998 Kenneth 
>Albanowski                                       
>Blkmem 8 disk 
>images:                                                          
>0: 10CBB074-10D55873 [VIRTUAL 10CBB074-10D55873] 
>(RO)                          
>1: 10DA0000-10DCFFFF [VIRTUAL 10DA0000-10DCFFFF] 
>(RW)                          
>2: 10DD0000-10DFFFFF [VIRTUAL 10DD0000-10DFFFFF] 
>(RW)                          
>3: 10C00000-10C0FFFF [VIRTUAL 10C00000-10C0FFFF] 
>(RW)                          
>4: 10C10000-10DFFFFF [VIRTUAL 10C10000-10DFFFFF] 
>(RW)                          
>5: 10C00000-10DFFFFF [VIRTUAL 10C00000-10DFFFFF] 
>(RW)                          
>6: 10DF0000-10DFFFFF [VIRTUAL 10DF0000-10DFFFFF] 
>(RW)                          
>7: 10C00000-10DEFFFF [VIRTUAL 10C00000-10DEFFFF] 
>(RW)                          
>PPP generic driver version 
>2.4.1                                               
>Can't allocate major number 31 for Memory Technology 
>Devices.                  
>NET4: Linux TCP/IP 1.0 for 
>NET4.0                                              
>IP Protocols: ICMP, UDP, 
>TCP                                                   
>IP: routing cache hash table of 512 buckets, 
>4Kbytes                           
>TCP: Hash tables configured (established 512 bind 
>512)                         
>NET4: Unix domain sockets 1.0/SMP for Linux 
>NET4.0.                            
>JFFS: Trying to mount device 
>1f:00.                                             
>jffs_build_fs()
>
>
>jffs_create_control()
>
>
>jffs_build_begin()
>
>
>jffs_create_control(): Allocation failed: 
>(c->fmc)                             
>JFFS: Failed to mount device 
>1f:00.                                            
>VFS: Mounted root (romfs filesystem) 
>readonly.                                 
>Freeing unused kernel memory: 0k 
>freed                                         
>eth0: using half-duplex 10Base-T 
>(RJ-45)                                      
>...
>
>JFFS tries to mount device 1f:00 (31:00), which is the same as the first
>
>blkmem arena, where my root filesystem is located. Maybe I'm not giving 
>the proper major-minor numbers to the mtdblock device... don't know...
>
>I forgot to tell that I'm using kernel 2.4.6 over VZ.
>
>Thanks,
>
>David Beamonte
>
>
>
>
>This message resent by the uclinux-dev at uclinux.org list server
>http://www.uClinux.org/
>This message resent by the uclinux-dev at uclinux.org list server http://www.uClinux.org/
>
>
>
>




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