intel p30, unlocking before loading driver, again

[Daniel Robinson]

I found the problem.

I think I have it working now.

Thanks, Dan

On 12/12/06, Josh Boyer <jwboyer at linux.vnet.ibm.com> wrote:
> On Tue, 2006-12-12 at 15:01 -0800, Daniel Robinson wrote:
> > I have a board with a P30 part on it and here are the knowns:
> >
> > 1) the P30 powers up with all blocks locked.
>
> Yes.
>
> >
> > 2) if the driver gets loaded with the blocks locked, mode is 0660
> > (rw-rw----), which allows me to open the device in O_RDWR mode, will
> > let me do ioctl() calls to unlock blocks, but won't let me write to
> > the device.  The ioctl() returns without error, but writing fails
> > because it is a read only file system.
> >
> > 3) In an attempt to increase robustness for a system that will be
> > embedded, I want to limit the amount of the part that is unlocked and
> > available for writing.  Ideally, I would like to control that
> > parametrically.
> >
> > I can't find the place in the flash device is checked for being
> > unlocked and the bits are set that indicate that it is a read-only
> > device.
>
> There are commands you can send to the chip to query this status.  See
> the datasheet for the flash chip.
>
> You can partition up your device and unlock partitions as needed.  Or
> you can do it from within a board driver if you need it at boot time for
> things like a root filesystem.
>
> josh
>
>