Re: [PATCH qemu 0/1] Update opentitan uart (part of supporting opentitan version 1)

[Alistair Francis <alistair23@gmail.com>]

On Fri, Mar 20, 2026 at 12:50 AM ~lexbaileylowrisc
<lexbaileylowrisc@git.sr.ht> wrote:
>
>
> This commit is part of our efforts to get support for opentitan version
> 1 in qemu, it replaces the previous proposed change, and incorporates
> some requests from review comments.
>
> The changes are now being made in the existing opentitan machine,
> instead of in a new machine. We have also avoided adding any new helper
> units.

Great! That's a good improvement.

Now when submitting patches you will want to try and have small self
contained changes. So instead of deleting the current code and adding
an entirely new file in one giant commit can you please make changes
to the existing code one change at a time. I suspect the UART probably
hasn't changed that much, so there shouldn't be too many commits to
update it to support OT 1.0. That makes it easier to bisect issues if
regressions are found and makes it a lot easier to review.

>
> This updates the UART device to match our branch, and to match version 1
> of opentitan.
> This is not where we were going to start previously, but now this is the
> easiest starting point.
>
> This commit adds a file that is a substantial copy of code already
> published under the MIT licence, and we aren't able to relicence it as
> GPL. (unable to get unanimous author agreement)

You might need a lawyer to review this. The new code says:

"""
* SPDX-License-Identifier: MIT
*
* Based on original ibex_uart implementation:
*  Copyright (c) 2020 Western Digital
*  Alistair Francis <alistair.francis@wdc.com>
"""

So it's based on my original GPL code. So I don't think it can be
relicensed as MIT. As such it should probably keep the original GPL
license. I am now a lawyer though. This type of thing will need to be
flagged in the commit message as well

Alistair

>
> Lex Bailey (1):
>   Replace opentitan UART device with newer version (opentitan 1.0)
>
>  hw/char/ibex_uart.c          | 569 -------------------------------
>  hw/char/meson.build          |   2 +-
>  hw/char/ot_uart.c            | 635 +++++++++++++++++++++++++++++++++++
>  hw/char/trace-events         |   8 +
>  hw/riscv/opentitan.c         |   3 +-
>  include/hw/char/ibex_uart.h  |  73 ----
>  include/hw/char/ot_uart.h    | 133 ++++++++
>  include/hw/riscv/opentitan.h |   4 +-
>  8 files changed, 781 insertions(+), 646 deletions(-)
>  delete mode 100644 hw/char/ibex_uart.c
>  create mode 100644 hw/char/ot_uart.c
>  delete mode 100644 include/hw/char/ibex_uart.h
>  create mode 100644 include/hw/char/ot_uart.h
>
> --
> 2.49.1
>