Re: [PATCH v2 00/25] hw/arm: Facebook SanMiguel BMC and TMP75-family sensors

["Cédric Le Goater" <clg@redhat.com>]

On 7/31/26 12:44, Emmanuel Blot wrote:
> This series adds the Facebook SanMiguel BMC, promotes the
> TMP75/TMP175/LM75B sensors from generic TMP105 stand-ins to improved,
> dedicated models, and introduces the test-side plumbing needed to
> exercise real I2C devices from functional tests without hardcoding QOM
> paths.
> 
> The work falls into four parts.
> 
> 1. TMP* sensor models
> 
> The TMP105 model was the only stand-in for a whole family of pin- and
> register-compatible parts, and several boards worked around the gap with
> private TYPE_TMP75 / TYPE_LM75 aliases that resolved back to a plain
> TMP105.
> 
> The model is first cleaned up for correctness and QEMU convention. One
> of those changes touches migrated state, which gains an optional
> subsection so existing streams stay compatible.
> 
> On that base, TMP75/TMP175/LM75B become variants selected by a small
> per-type class descriptor. The variant is class data, so the wire format
> is unchanged and all variants share the existing vmstate. qtest coverage
> is added for the per-variant behaviour. The existing BMC boards then
> drop their local aliases and instantiate the real models.
> 
> 2. SanMiguel BMC
> 
> A new AST2600-based machine for the Facebook SanMiguel BMC, derived from
> its device tree. It wires up three TMP75 sensors, IO expanders, FRU
> EEPROMs, an I2C mux and an RTC across its I2C buses, and provides its
> RAM, flash and networking; the FRU EEPROMs are populated with data read
> from physical hardware. A functional test boots the OpenBMC image and
> drives each sensor over QOM, checking the guest hwmon interface reports
> the injected value back.
> 
> 3. Python device locator
> 
> A QOM path names a device by its position under the object that owns it,
> in enumeration order — it says nothing about where the device sits in
> the bus topology. From a QOM path alone it is impossible to tell where a
> device is actually connected or what purpose it serves.
> 
> DeviceLocator is a pure-Python helper that resolves a device from a
> string descriptor of its position — bus, address, type, on-bus index —
> by walking the bus/device hierarchy. It uses only standard QOM queries
> over QMP: no new QEMU commands, no model changes. A self-check exercises
> the grammar and its error paths against a paused SanMiguel BMC; it needs
> no disk image and runs in about a second.
> 
> Note: the helper adopts the 3.10 type-hint syntax rather than the 3.9
> equivalents; 3.9 reached end of life on 2025-10-31. The import is
> guarded so the module still loads on 3.9 and dependent tests skip there.
> 
> Two small test-framework fixes ride along: the set_machine probe VM now
> gets the per-test workdir instead of the hardcoded /var/tmp default, and
> the Aspeed OpenBMC helper can optionally assert the booted device-tree
> model.
> 
> 4. Catalina follow-ups
> 
> The final three commits are the tail of the earlier "hw/arm: improve
> Aspeed Catalina BMC emulation" series: functional tests for the PCA9555
> and PCA9554 IO expanders, plus the PCA9554 change that drives its input
> pins externally. They were held back because reaching such devices from
> a test needs a stable way to reference them by bus position — the QOM
> re-parenting patch tried then was rejected, and the device locator now
> unblocks them.
> 
> Based on:
> 
>    repo:   https://github.com/legoater/qemu.git
>    branch: aspeed-11.1
>    commit: 04d27371e3 ("hw/arm: catalina: add NIC and FIO temperature sensors")
> 
> Signed-off-by: Emmanuel Blot <emmanuel.blot@free.fr>
> ---
> Changes in v2:
> - Simplify TMP105 multiple variant initialization
> - Improve reliability against malformed device locator strings
> - Remove an obsolete reference to INA23x devices from a commit log message
> - Rebase patch series on aspeed-next branch
> - Fix invalid JSON syntax in SanMiguel FRU descriptions
> - Link to v1: https://lore.kernel.org/qemu-devel/20260729-sanmiguel-bmc-locator-v1-0-c8f9a8d101f6@free.fr
> 
> To: qemu-devel@nongnu.org
> Cc: Philippe Mathieu-Daudé <philmd@mailo.com>
> Cc: Cédric Le Goater <clg@kaod.org>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: Steven Lee <steven_lee@aspeedtech.com>
> Cc: Jamin Lin <jamin_lin@aspeedtech.com>
> Cc: Kane Chen <kane_chen@aspeedtech.com>
> Cc: Andrew Jeffery <andrew@codeconstruct.com.au>
> Cc: Joel Stanley <joel@jms.id.au>
> Cc: qemu-arm@nongnu.org
> Cc: Fabiano Rosas <farosas@suse.de>
> Cc: Laurent Vivier <lvivier@redhat.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Thomas Huth <th.huth+qemu@posteo.eu>
> Cc: "Daniel P. Berrangé" <berrange@redhat.com>
> 
> ---
> Emmanuel Blot (25):
>        hw/sensor: tmp105: make device state private to the implementation
>        hw/sensor: tmp105: name the parent object field parent_obj
>        hw/sensor: tmp105: implement Resettable reset
>        hw/sensor: tmp105: enforce the configurable fault queue
>        hw/sensor: tmp105: describe the temperature property
>        hw/arm: aspeed: guard board-local temperature-sensor aliases
>        hw/sensor: tmp105: add TMP75, TMP175 and LM75B variants
>        tests/qtest: tmp105: cover the ALERT fault queue
>        tests/qtest: tmp105: cover the TMP75, TMP175 and LM75B variants
>        tests/qtest: tmp105: cover one-shot and fault-queue write immunity
>        tests/qtest: tmp105: cover shutdown clearing the ALERT across variants
>        hw/arm: sanmiguel: add Facebook SanMiguel BMC machine
>        hw/arm: sanmiguel: populate EEPROM data
>        hw/arm: catalina: use the real TMP75 model
>        hw/arm: fuji: use the real TMP75 and LM75B temperature sensors
>        tests/functional: aspeed: optionally check the device tree model on boot
>        tests/functional: give the set_machine probe VM the test workdir
>        tests/functional: add a pure-Python device-locator resolver
>        tests/functional: add a device-locator self-check
>        tests/functional: aspeed: add hwmon sensor read helpers
>        tests/functional/arm: sanmiguel: add BMC boot test
>        tests/functional/arm: catalina: test TMP75
>        tests/functional/arm: catalina: test PCA9555 IO expander via QOM
>        hw/arm: catalina: drive pca9554 io expander input pins externally
>        tests/functional/arm: catalina: test PCA9554 IO expander via QOM
> 
>   hw/arm/aspeed_ast2600_catalina.c              |  14 +-
>   hw/arm/aspeed_ast2600_fuji.c                  |  16 +-
>   hw/arm/aspeed_ast2600_sanmiguel.c             | 405 ++++++++++++++++++
>   hw/arm/meson.build                            |   1 +
>   hw/sensor/tmp105.c                            | 304 ++++++++++---
>   include/hw/sensor/tmp105.h                    |  46 +-
>   tests/functional/arm/meson.build              |   3 +
>   tests/functional/arm/test_aspeed_catalina.py  | 107 ++++-
>   tests/functional/arm/test_aspeed_sanmiguel.py |  72 ++++
>   tests/functional/arm/test_device_locator.py   | 120 ++++++
>   tests/functional/aspeed.py                    |  21 +-
>   tests/functional/qemu_test/locator.py         | 586 ++++++++++++++++++++++++++
>   tests/functional/qemu_test/testcase.py        |   2 +-
>   tests/qtest/tmp105-test.c                     | 359 ++++++++++++++++
>   14 files changed, 1934 insertions(+), 122 deletions(-)
> ---
> base-commit: e5d3f5ac8633de310066f14862b17e4cac8ef8a5
> change-id: 20260729-sanmiguel-bmc-locator-db13cceae66c
> 
> Best regards,
> --
> Emmanuel Blot <emmanuel.blot@free.fr>
> 

Applied 1-16 to

     https://github.com/legoater/qemu aspeed-next


Functional tests need to identify devices in the bus topology and
we lack support for that. Several recent threads have touched this
topic:

   - "[PATCH v5 0/8] hw/sensor: Add new device emulation for TI ADC128D818" [1]
   - "Call to clean up QOM onboard devices lacking a parent" [2]
   - "[PATCH RFC 001/134] qom: Introduce object_new_child()" [3]
   - "[PATCH RFC v2 0/137] qom: Make composition-tree parenting mandatory" [4]
   - "[PATCH v2 0/25] hw/arm: Facebook SanMiguel BMC and TMP75-family sensors" [5]

Not addressed yet. It's still maturing, like all the good stuff.

Thanks,

C.

[1] https://lore.kernel.org/qemu-devel/20260701-i2c-adc128d818-anacapa-v5-6-fe8292d86b38@free.fr
[2] https://lore.kernel.org/qemu-devel/87se5scipx.fsf@pond.sub.org
[3] https://lore.kernel.org/qemu-devel/20260711223707.42139-1-graf@amazon.com
[4] https://lore.kernel.org/qemu-devel/20260718213652.37673-1-graf@amazon.com
[5] https://lore.kernel.org/qemu-devel/20260731-sanmiguel-bmc-locator-v2-0-1266926ba769@free.fr