Fwd: Hello -- NAND/NOR Flash design for GTA02

Andy Green andy at openmoko.com
Fri Jan 11 12:53:10 CET 2008


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Somebody in the thread at some point said:
> Hi, Werner, Willie, Nod:
> 
> production information now:
> 
> device nand0 <neo1973-nand>, # parts = 6
> #: name                        size            offset          mask_flags
> 0: u-boot              0x00040000      0x00000000      0
> 1: u-boot_env          0x00040000      0x00040000      0
> 2: kernel              0x00800000      0x00080000      0
> 3: splash              0x000a0000      0x00880000      0
> 4: factory             0x00040000      0x00920000      0
> 5: rootfs              0x076a0000      0x00960000      0

Okay by me, but one thing... there is a 20s target now for boot time.
We have to decide what to do to get ourselves much closer to this (I
don't think we will reach it) because we are far away from it right now.

One of the choices that we may do is to cut rootfs into two, because the
amount of time spent mounting is proportional only to the partition
size.  We can create a 50MB "early boot" partition we can mount to get
started with the initscripts, and mount the remaining 200MB in the
background at a different mountpoint.  This will reduce the effective
initial JFFS2 mount time to 20% of what it is now.

Werner is looking at trying to find a different way to optimize the
mount time, we said that early next week we will finalize the decision
on the partition set we will use, but I would propose we cut the rootfs
in two as described if Werner didn't have luck in speeding it up by a
considerable amount.  Of course even if he speeds it up by 5% that is
really good either way.

If we go that way, we need to consider the impact on packaging paths.
Probably we should leave all the packages to point where they are, and
have /usr and so on in the "early boot" partition.  Then other packages
should place stuff in something like /opt or /usr/local which is mounted
or mounted --bind to the second, larger partition.

- -Andy
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