MTD partitions

MTD partitions

[Tobias Arp]

Hi,  
  
on my old kernel (2.4.21 and the arm linux patch rmk2) it was possible to configure the  
remapping of the flash in the xconfig/menuconfig files. I have created the mtd partitions in  
physmap.c. So when i have made:  
  
cat /proc/mtd  
  
i got these outputs  
  
dev: size erasesize name  
mtd0: 00400000 00010000 ""physically mapped flash"  
mtd1: 00060000 00010000 ""USER fs"  
  
My flash has a size of 4 MBytes and typically 64kbytes sector size. It started physically at  
offset 0x10000000 and is connected via a 16 bit bus. These were also the configuration  
paramter which i added to my config files. This must be mtd0. The mtd1 device is the partition  
which i have configured in physmap.c.  
  
After applieing the mtd snapshot(mtd-snapshot-20040407.tar.bz2) i have used  
physmap_configure with the same data:  
  
physmap_configure(0x10000000,0x00400000,2,NULL);  
  
0x10000000 = physical flash base  
0x00400000 = Flash size  
2 = 16 Bit Buswidth  
  
Then i have used  
  
physmap_set_partitions(at91_mtd_parts,1);  
  
to add my USER fs  
  
static struct mtd_partition at91_mtd_parts[] __initdata = {  
 {  
 .name = "USER fs",  
 .offset = 0x00380000,  
 .size = 0x00060000,  
 }  
};  
  
Now i get following outputs when i make cat proc/mtd  
  
dev: size erasesize name  
mtd0: 00060000 00010000 ""USER fs"  
  
where is the "old mtd0" device with the whole flashsize ?  
  
And how can i remove these messages from the startup of the kernel:  
  
  
>cfi_cmdset_0002: Disabling erase-suspend-program due to code brokenness.  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
- Is there any patch for this problem ? -  
  
>kmod: failed to exec /sbin/modprobe -s -k cmdlinepart, errno = 2  
>cmdlinepart partition parsing not available  
>kmod: failed to exec /sbin/modprobe -s -k RedBoot, errno = 2  
>RedBoot partition parsing not available  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
- Is there any reason for these messages ? -  
  
  
Regards  
Tobias Arp  
  
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MTD Partitions

[Nikhil Bansal (nikbansa)]

Hi,

>From what I understand you need to provide the partitioning details of
MTD devices at the compile time. I was wondering if there is any way to
partition a flash device at runtime based on the sectors. For Example:
partition 1 from sector 1 to sector 10, partition 2 from sector 11 to
sector 20. 

The thing is that we have a board with a flash chip on it and
configuration of this chip may vary based on several factors. I don't
have the luxury of compiling the kernel for each such requirement :( I
think I read somewhere that at this point, partitioning can be done at
compile time only but just wanted to confirm.

By the way, we can keep the number of partitions fixed but size needs to
be varied. Please let me know if it can be done.

Thanks in advance,
Nikhil

Re: MTD Partitions

[Josh Boyer]

On 9/22/06, Nikhil Bansal (nikbansa) <nikbansa@cisco.com> wrote:
> Hi,
>
> >From what I understand you need to provide the partitioning details of
> MTD devices at the compile time. I was wondering if there is any way to
> partition a flash device at runtime based on the sectors. For Example:
> partition 1 from sector 1 to sector 10, partition 2 from sector 11 to
> sector 20.
>
> The thing is that we have a board with a flash chip on it and
> configuration of this chip may vary based on several factors. I don't
> have the luxury of compiling the kernel for each such requirement :( I
> think I read somewhere that at this point, partitioning can be done at
> compile time only but just wanted to confirm.
>
> By the way, we can keep the number of partitions fixed but size needs to
> be varied. Please let me know if it can be done.

You might want to take a look at UBI.  It can do much of what you are
looking for, depending on how complex things are.  It's still a work
in progress, but it's usable.

http://linux-mtd.infradead.org/doc/ubi.html

josh

Re: MTD Partitions

[Michael Trimarchi]

Nikhil Bansal (nikbansa) wrote:

>Hi,
>
>>From what I understand you need to provide the partitioning details of
>MTD devices at the compile time. I was wondering if there is any way to
>partition a flash device at runtime based on the sectors. For Example:
>partition 1 from sector 1 to sector 10, partition 2 from sector 11 to
>sector 20. 
>
>The thing is that we have a board with a flash chip on it and
>configuration of this chip may vary based on several factors. I don't
>have the luxury of compiling the kernel for each such requirement :( I
>think I read somewhere that at this point, partitioning can be done at
>compile time only but just wanted to confirm.
>
>By the way, we can keep the number of partitions fixed but size needs to
>be varied. Please let me know if it can be done.
>
>Thanks in advance,
>Nikhil
>
>______________________________________________________
>Linux MTD discussion mailing list
>http://lists.infradead.org/mailman/listinfo/linux-mtd/
>
>  
>
Hi,
I think that you can use cmdline partition option in the kernel. I use 
it in the IXDP465
Regards Michael