Question about partition layout and Flash part

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1

Hello,
        I am kind of new to this all. Sorry to be asking so many
novice questions here, I would really appreciate if someone could drop
pointers or guide me. I would be happy to study it. I was reading the
following link:

http://elinux.org/BeagleBoardNAND

Q1. Within the first few lines, the article shows a "Partition
Layout", where and how do these get defined ? Do we do it in the
Xloader ?

Q2. Is this Partition layout for a flash part internal to the OMAP or
is it an external flash part which sits on the BeagleBoard ?

Q3. In either of the cases, are these flash parts, Raw flash or
Managed flash ?

Q4. Is my understanding correct, when I say that a filesystem like
"ext3, VFAT etc" may live on a "Managed Flash" but not on "Raw
Flash" ? Raw Flash would use something specific like "jffs". Is my
understanding correct ?

Thanks,
Vijay

2

Hello,
I am kind of new to this all. Sorry to be asking so many
novice questions here, I would really appreciate if someone could drop
pointers or guide me. I would be happy to study it. I was reading the
following link:

http://elinux.org/BeagleBoardNAND

Q1. Within the first few lines, the article shows a “Partition
Layout”, where and how do these get defined ? Do we do it in the
Xloader ?

Usually with NAND flash the partition layout is merely a contractual thing, there is no partition table anywhere on the flash. There are two options that are often used:

  1. Partition table is defined in U-boot and it passes it to kernel via command line (mtdparts=…)
  2. Partition table is built into the kernel. Usually into the board file.

The example on that page seems to have option #2.
“cmdlinepart partition parsing not available”

Q2. Is this Partition layout for a flash part internal to the OMAP or
is it an external flash part which sits on the BeagleBoard ?

OMAP has no internal flash. So it is for the external part.

Q3. In either of the cases, are these flash parts, Raw flash or
Managed flash ?

RAW. The article you refers talks about RAW NAND.

Q4. Is my understanding correct, when I say that a filesystem like
“ext3, VFAT etc” may live on a “Managed Flash” but not on “Raw
Flash” ? Raw Flash would use something specific like “jffs”. Is my
understanding correct ?

Correct.

(e)MMC would qualify as managed flash for example.

  • Juha
3

> Hello,
> I am kind of new to this all. Sorry to be asking so many
> novice questions here, I would really appreciate if someone could drop
> pointers or guide me. I would be happy to study it. I was reading the
> following link:

>BeagleBoardNAND - eLinux.org

> Q1. Within the first few lines, the article shows a "Partition
> Layout", where and how do these get defined ? Do we do it in the
> Xloader ?

> Usually with NAND flash the partition layout is merely a contractual thing,

there is no partition table anywhere on the flash. There are two options
that are often used:

1. Partition table is defined in U-boot and it passes it to kernel via
command line (mtdparts=...)
2. Partition table is built into the kernel. Usually into the board file.

The example on that page seems to have option #2.
"cmdlinepart partition parsing not available"

How does the xloader have knowledge of very to jump to, incase it does
not have a partition table ?

4

Also, Suppose I want another "mtd" partition, other than the ones that
are already listed, how can I add a new MTD partition ? Say for
example I want one MTD partition to be "jffs" and another to be
"yaffs" ?

Thanks,
VIjay