[PATCH v3 0/3] firmware: arm_scmi: fix module auto-loading

[Hans de Goede]

Hi All,

Here is a patch series fixing arm_scmi module autoloading this combines:

1. Patch 1/2 from Bjorn to add support for scmi bus modaliases to modpost:
https://lore.kernel.org/all/20260618-scmi-modalias-v2-1-8c7547c1be21@xxxxxxxxxxxxxxxx/

2. RFC 2/2 from Cristian which pre-populates the scmi { protocol, name }
tupple list with standard protocol info to break the circular dep:
https://patch.msgid.link/20250203100154.140877-2-cristian.marussi@xxxxxxx

1. is not enough by itself because driver module auto-loading requires
the devices to already be created for udev to get the necessary uevents
based on which udev auto-loads modules.

But SCMI devices are only created after their { protocol, name } tupples
have been registered which is done from scmi_driver_register(), creating
a circular dependency.

2. breaks the circular dependency by pre-populating the { protocol, name }
list with the standard protocols. This allows the devices to be created
before the module with the driver is loaded, after which module auto
loading works the same as it does on any other bus.

I've tested this on a T14s Snapdragon laptop with Fedora's kernel config
where scmi_cpufreq is a module. With this series scmi_cpufreq correctly
autoloads even if it is not included in the initramfs.

I've added a 3th patch extending the pre-populating to also include all
the { protocol, name } tupples for the in tree SCMI drivers for IMX
vendor protocols, so that module auto-loading will work for all in tree
drivers.

Out of tree drivers can still register new tupples as before but their
modules will need to be manually loaded (also as before).

Regards,

Hans


Bjorn Andersson (1):
  module: add SCMI device table alias support

Cristian Marussi (1):
  firmware: arm_scmi: Pre-register protocol, name tupples for standard
    protocols

Hans de Goede (1):
  firmware: arm_scmi: Pre-register protocol, name tupples for IMX
    protocols

 MAINTAINERS                       |  1 +
 drivers/firmware/arm_scmi/bus.c   | 75 +++++++++++++++++++++++--------
 include/linux/device-id/scmi.h    | 19 ++++++++
 include/linux/mod_devicetable.h   |  1 +
 include/linux/scmi_protocol.h     |  6 +--
 scripts/mod/devicetable-offsets.c |  4 ++
 scripts/mod/file2alias.c          | 11 +++++
 7 files changed, 94 insertions(+), 23 deletions(-)
 create mode 100644 include/linux/device-id/scmi.h

-- 
2.55.0