Difference between revisions of "Create a FLASH partition to store user's HOME"

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(New page: If you ever did some hacking/devt on your APF board and used ''/root/'' to download or install your experiments, I'm sure you got frustrated when it come the time where you had to reflash ...)
 
(Declare partition in U-Boot)
Line 19: Line 19:
 
<pre class="apf">
 
<pre class="apf">
 
BIOS> setenv mtdparts mtdparts=mxc_nand.0:640k(U-boot)ro,384k(U-boot_env),512k(firmware),5M(kernel),200M(rootfs),-(user)
 
BIOS> setenv mtdparts mtdparts=mxc_nand.0:640k(U-boot)ro,384k(U-boot_env),512k(firmware),5M(kernel),200M(rootfs),-(user)
 +
BIOS> printenv mtdparts
 +
mtdparts=mtdparts=mxc_nand.0:640k(U-boot)ro,384k(U-boot_env),512k(firmware),5M(kernel),200M(rootfs),-(user)
 +
</pre>
 +
* Save your changes and boot Linux:
 +
<pre class="apf">
 +
BIOS> saveenv
 +
BIOS> boot
 
</pre>
 
</pre>
  
 
===apf9328===
 
===apf9328===
 
TBDL
 
TBDL
 +
 +
==Linux==
 +
* In Linux boot message you should see you newly created partition detected:
 +
<pre class="apf">
 +
6 cmdlinepart partitions found on MTD device mxc_nand.0                                                                                                                           
 +
Creating 6 MTD partitions on "mxc_nand.0":                                                                                                                                         
 +
0x000000000000-0x0000000a0000 : "U-boot"                                                                                                                                           
 +
0x0000000a0000-0x000000100000 : "U-boot_env"                                                                                                                                       
 +
0x000000100000-0x000000180000 : "firmware"                                                                                                                                         
 +
0x000000180000-0x000000680000 : "kernel"                                                                                                                                           
 +
0x000000680000-0x00000ce80000 : "rootfs"                                                                                                                                           
 +
0x00000ce80000-0x000010000000 : "user"
 +
</pre>
 +
* Check a device node was created for your new partition (''/dev/mtdblock5''):
 +
<pre class="apf">
 +
# ls /dev/mtdblock*
 +
/dev/mtdblock0  /dev/mtdblock2  /dev/mtdblock4
 +
/dev/mtdblock1  /dev/mtdblock3  /dev/mtdblock5
 +
</pre>
 +
* I will use JFFS2 as filesystem for the partition but as soon as UBIFS will be stable enough it will be usable too. So create a temporary mount point and mount the partition. It will be automatically formatted to JFSS2:
 +
<pre class="apf">
 +
# mkdir /tmp/nand
 +
# mount -t jffs2 /dev/mtdblock5 /tmp/nand
 +
# ls /tmp/nand/
 +
</pre>
 +
* Move your user data to the partition:
 +
<pre class="apf">
 +
# cp -r /root/* /tmp/nand/
 +
# cp -r /root/.* /tmp/nand/
 +
</pre>
 +
* Makes it automatically mounted at every boot by adding it to ''/etc/fstab'':
 +
<pre class="apf">
 +
# vi /etc/fstab
 +
...
 +
sysfs          /sys          sysfs    defaults          0      0       
 +
usbfs          /proc/bus/usb  usbfs    defaults          0      0
 +
/dev/mtdblock5  /root          jffs2    defaults          0      0  <<-----------------
 +
</pre>
 +
* Now you're done. Reboot and enjoy ! ;-)
 +
<pre class="apf">
 +
# df -h
 +
Filesystem                Size      Used Available Use% Mounted on
 +
rootfs                  200.0M    17.8M    182.2M  9% /
 +
/dev/root              200.0M    17.8M    182.2M  9% /
 +
none                    64.0k        0    64.0k  0% /dev
 +
tmpfs                    61.2M    44.0k    61.1M  0% /tmp
 +
>>> /dev/mtdblock5          49.5M      4.0M    45.5M  8% /root <<<
 +
# ls /root/
 +
</pre>

Revision as of 23:42, 23 October 2009

If you ever did some hacking/devt on your APF board and used /root/ to download or install your experiments, I'm sure you got frustrated when it come the time where you had to reflash the whole rootfs. Indeed, by default, /root/ is located in the same partition as the rootfs image and so everything you did will be overwritten. Well you can always backup your data on a SD/microSD or through NFS before doing the rootfs flashing but I think, like me, you are little bit lazy.

So in this small tutorial I will explain you how to setup the FLASH to store your personnal data on a separated partition and so avoid the backup process when updating your rootfs.

Declare partition in U-Boot

apf27

  • Check your NAND FLASH size:
BIOS> nand info

Device 0: NAND 256MiB 1,8V 16-bit, sector size 128 KiB
  • So here I have 256MBytes. Then check current partitionning:
BIOS> printenv mtdparts
mtdparts=mtdparts=mxc_nand.0:640k(U-boot)ro,384k(U-boot_env),512k(firmware),5M(kernel),-(rootfs)
  • I have the default APF27 partitionning scheme. Now I will reduce rootfs size to 200 MBytes and so have the remaining (50 MBytes) for my "user" partition:
BIOS> setenv mtdparts mtdparts=mxc_nand.0:640k(U-boot)ro,384k(U-boot_env),512k(firmware),5M(kernel),200M(rootfs),-(user)
BIOS> printenv mtdparts
mtdparts=mtdparts=mxc_nand.0:640k(U-boot)ro,384k(U-boot_env),512k(firmware),5M(kernel),200M(rootfs),-(user)
  • Save your changes and boot Linux:
BIOS> saveenv
BIOS> boot

apf9328

TBDL

Linux

  • In Linux boot message you should see you newly created partition detected:
6 cmdlinepart partitions found on MTD device mxc_nand.0                                                                                                                             
Creating 6 MTD partitions on "mxc_nand.0":                                                                                                                                          
0x000000000000-0x0000000a0000 : "U-boot"                                                                                                                                            
0x0000000a0000-0x000000100000 : "U-boot_env"                                                                                                                                        
0x000000100000-0x000000180000 : "firmware"                                                                                                                                          
0x000000180000-0x000000680000 : "kernel"                                                                                                                                            
0x000000680000-0x00000ce80000 : "rootfs"                                                                                                                                            
0x00000ce80000-0x000010000000 : "user"
  • Check a device node was created for your new partition (/dev/mtdblock5):
# ls /dev/mtdblock*
/dev/mtdblock0  /dev/mtdblock2  /dev/mtdblock4
/dev/mtdblock1  /dev/mtdblock3  /dev/mtdblock5
  • I will use JFFS2 as filesystem for the partition but as soon as UBIFS will be stable enough it will be usable too. So create a temporary mount point and mount the partition. It will be automatically formatted to JFSS2:
# mkdir /tmp/nand
# mount -t jffs2 /dev/mtdblock5 /tmp/nand
# ls /tmp/nand/
  • Move your user data to the partition:
# cp -r /root/* /tmp/nand/
# cp -r /root/.* /tmp/nand/
  • Makes it automatically mounted at every boot by adding it to /etc/fstab:
# vi /etc/fstab
...
sysfs           /sys           sysfs    defaults          0      0        
usbfs           /proc/bus/usb  usbfs    defaults          0      0
/dev/mtdblock5  /root          jffs2    defaults          0      0   <<-----------------
  • Now you're done. Reboot and enjoy ! ;-)
# df -h
Filesystem                Size      Used Available Use% Mounted on
rootfs                  200.0M     17.8M    182.2M   9% /
/dev/root               200.0M     17.8M    182.2M   9% /
none                     64.0k         0     64.0k   0% /dev
tmpfs                    61.2M     44.0k     61.1M   0% /tmp
>>> /dev/mtdblock5           49.5M      4.0M     45.5M   8% /root <<<
# ls /root/