Re: [RFC PATCH v6 1/2] hw/misc/sifive_u_otp: Add write function and write-once protection

[Bin Meng]

Hi Green,

On Wed, Oct 14, 2020 at 3:02 PM Green Wan <green.wan@sifive.com> wrote:
>
> On Wed, Oct 14, 2020 at 1:37 PM Bin Meng <bmeng.cn@gmail.com> wrote:
> >
> > Hi Green,
> >
> > On Mon, Sep 28, 2020 at 6:12 PM Green Wan <green.wan@sifive.com> wrote:
> > >
> > >  - Add write operation to update fuse data bit when PWE bit is on.
> > >  - Add array, fuse_wo, to store the 'written' status for all bits
> > >    of OTP to block the write operation.
> > >
> > > Signed-off-by: Green Wan <green.wan@sifive.com>
> > > Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> > > ---
> > >  hw/misc/sifive_u_otp.c         | 30 +++++++++++++++++++++++++++++-
> > >  include/hw/misc/sifive_u_otp.h |  3 +++
> > >  2 files changed, 32 insertions(+), 1 deletion(-)
> > >
> >
> > I am not sure how you tested this. I wrote a simple U-Boot command to
> > call U-Boot sifive-otp driver to test the write functionality, but it
> > failed.
> >
> > => misc write otp@10070000 0 80200000 10
>                                                       ^^^^^^^^^
> Quick ask, how about 'md 80200000'?
>
> I didn't use 'misc write' command. I can check afterward.

Note 'misc write' is a new U-Boot command I just added for testing
this QEMU functionality. Please use the U-Boot patch below:
http://patchwork.ozlabs.org/project/uboot/patch/1602657292-82815-1-git-send-email-bmeng.cn@gmail.com/

>
> > => misc read  otp@10070000 0 80400000 10
> > => md 80400000
> > 80400000: ffffffff ffffffff ffffffff ffffffff    ................
> > 80400010: 00000000 00000000 00000000 00000000    ................
> > 80400020: 00000000 00000000 00000000 00000000    ................
> > 80400030: 00000000 00000000 00000000 00000000    ................
> > 80400040: 00000000 00000000 00000000 00000000    ................
> > 80400050: 00000000 00000000 00000000 00000000    ................
> > 80400060: 00000000 00000000 00000000 00000000    ................
> > 80400070: 00000000 00000000 00000000 00000000    ................
> > 80400080: 00000000 00000000 00000000 00000000    ................
> > 80400090: 00000000 00000000 00000000 00000000    ................
> > 804000a0: 00000000 00000000 00000000 00000000    ................
> > 804000b0: 00000000 00000000 00000000 00000000    ................
> > 804000c0: 00000000 00000000 00000000 00000000    ................
> > 804000d0: 00000000 00000000 00000000 00000000    ................
> > 804000e0: 00000000 00000000 00000000 00000000    ................
> > 804000f0: 00000000 00000000 00000000 00000000    ................
> > => misc write otp@10070000 0 80200010 10
> > => misc read  otp@10070000 0 80400010 10
> > => md 80400000
> > 80400000: ffffffff ffffffff ffffffff ffffffff    ................
> > 80400010: ffffffff ffffffff ffffffff ffffffff    ................
> > 80400020: 00000000 00000000 00000000 00000000    ................
> > 80400030: 00000000 00000000 00000000 00000000    ................
> > 80400040: 00000000 00000000 00000000 00000000    ................
> > 80400050: 00000000 00000000 00000000 00000000    ................
> > 80400060: 00000000 00000000 00000000 00000000    ................
> > 80400070: 00000000 00000000 00000000 00000000    ................
> > 80400080: 00000000 00000000 00000000 00000000    ................
> > 80400090: 00000000 00000000 00000000 00000000    ................
> > 804000a0: 00000000 00000000 00000000 00000000    ................
> > 804000b0: 00000000 00000000 00000000 00000000    ................
> > 804000c0: 00000000 00000000 00000000 00000000    ................
> > 804000d0: 00000000 00000000 00000000 00000000    ................
> > 804000e0: 00000000 00000000 00000000 00000000    ................
> > 804000f0: 00000000 00000000 00000000 00000000    ................
> >
> > But it can read the serial number at offset 0x3f0
> >
> > => misc read  otp@10070000 3f0 80400010 10
> > => md 80400000
> > 80400000: ffffffff ffffffff ffffffff ffffffff    ................
> > 80400010: 00000001 fffffffe ffffffff ffffffff    ................
> > 80400020: 00000000 00000000 00000000 00000000    ................
> > 80400030: 00000000 00000000 00000000 00000000    ................
> > 80400040: 00000000 00000000 00000000 00000000    ................
> > 80400050: 00000000 00000000 00000000 00000000    ................
> > 80400060: 00000000 00000000 00000000 00000000    ................
> > 80400070: 00000000 00000000 00000000 00000000    ................
> > 80400080: 00000000 00000000 00000000 00000000    ................
> > 80400090: 00000000 00000000 00000000 00000000    ................
> > 804000a0: 00000000 00000000 00000000 00000000    ................
> > 804000b0: 00000000 00000000 00000000 00000000    ................
> > 804000c0: 00000000 00000000 00000000 00000000    ................
> > 804000d0: 00000000 00000000 00000000 00000000    ................
> > 804000e0: 00000000 00000000 00000000 00000000    ................
> > 804000f0: 00000000 00000000 00000000 00000000    ................

Regards,
Bin