[Buildroot] Dataflash rootfs problems (still)
ulf at atmel.com
Wed Oct 24 22:49:40 UTC 2007
ons 2007-10-24 klockan 18:54 +0200 skrev Jorge S.:
> 2007/10/24, Ulf Samuelsson <ulf at atmel.com>:
> ons 2007-10-24 klockan 18:20 +0200 skrev Jorge S.:
> > Hello all:
> > I've sucessfully built several root filesystems for my
> custom board
> > (AT91RM9200 + 8MiB DataFlash), but now i'm facing
> a strange
> > problem.
> > I'm using a JFFS2 filesystem on an MTD partition into the
> > my rootfs boots OK, but ONLY for the first time. See steps:
> > 1) Create a rootfs JFFS2 image using buildroot -> OK
> > 2) Erase entire flash partition: I boot from an initrd
> > mtd-tools for this purpouse. -> OK
> > 3) Dump the rootfs image "rootfs.jffs2" into the Dataflash
> (i use
> > loadb from u-boot here...) -> OK
> > 4) Boot the system... -> OK
> > 5) Login and issue a simple reboot, no other
> > else.... -> OK
> If you run the SPI faster than 5 Mbps, you are basically
> See Errata #13 in the datasheet.
> You will need to add an external AND gate if you want to run
> * AND output to the dataflash chip select,
> * one input to the NPCS0
> * one input to a GPIO
> The driver needs to be adapted for this.
> So, there's a flash corruption on the 1st boot?,
> I'm a little confused now...why u-boot looks like writing OK then?
> I've sucessfully uploaded hundreds of kernels and initrds images to
> the dataflash.
> During the 1st boot, Dropbear creates and "writes" the generated keys,
> maybe is this *write* operation the one screwing up the dataflash?
> And last question, which one is the best way to solve this by
> software? I suppose i can "slow down" the SPI speed somewhere in the
> kernel or board config at u-boot isn't it?
> Thanks for helping Ulf.
It is one potential problem, which needs to be addressed,
in U-Boot, linux and dataflashboot.bin.
There may be other problems, which I am not aware of, but
it is best to fix this to start with.
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