[PATCH 0/3] firmware: arm_scmi: Enable building SCMI as module

[Cristian Marussi]

Hi Sudeep,

On Mon, Sep 07, 2020 at 12:29:17PM +0100, Sudeep Holla wrote:
> Hi,
> 
> Though it was initially developed as module, so some reason(I can't
> recollect why apart from some structuring arounf the way bus and
> protocols were initialised), it was merged as a built-in only driver.
> 
> Now, there is a need to build this as modules. This is mainly needed
> by virtio transport. This also aligns well with GKI modularisation
> efforts.
> 

This works for me as a module, but it gave me issues when compiled builtin
since the some SCMI drivers (hwmon, cpufreq) look for the SCMI bus too early
when both them and the core are compiled as builtins.

[    2.226029] rtc-efi rtc-efi.0: setting system clock to 2020-09-07T10:51:36 UTC (1599475896)
[    2.235091] rtc-pl031 1c170000.rtc: registered as rtc1
[    2.240767] i2c /dev entries driver
[    2.246522] Driver 'scmi-hwmon' was unable to register with bus_type 'scmi_protocol' because the bus was not initialized.
[    2.259037] sp805-wdt 1c0f0000.wdt: registration successful
[    2.265464] Driver 'scmi-cpufreq' was unable to register with bus_type 'scmi_protocol' because the bus was not initialized.
[    2.278905] mmci-pl18x 1c050000.mmci: mmc0: PL180 manf 41 rev0 at 0x1c050000 irq 8,0 (pio)

This dirty trick below solves for me though the builtin issue (and still runs
fine when modularized):

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 2a1396b74fa5..b69bb174344d 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -939,7 +939,11 @@ static int __init scmi_driver_init(void)
 
        return platform_driver_register(&scmi_driver);
 }
+#ifdef MODULE
 module_init(scmi_driver_init);
+#else
+subsys_initcall(scmi_driver_init);
+#endif
 
 static void __exit scmi_driver_exit(void)
 {

Thanks

Cristian

> --
> Regards,
> Sudeep
> 
> Sudeep Holla (3):
>   firmware: arm_scmi: Move scmi bus init and exit calls into the driver
>   firmware: arm_scmi: Move scmi protocols initialisation into the driver
>   firmware: arm_scmi: Enable building as a single module
> 
>  drivers/firmware/Kconfig            |  2 +-
>  drivers/firmware/Makefile           |  2 +-
>  drivers/firmware/arm_scmi/Makefile  |  4 +++-
>  drivers/firmware/arm_scmi/bus.c     |  6 ++----
>  drivers/firmware/arm_scmi/clock.c   |  7 +------
>  drivers/firmware/arm_scmi/common.h  | 24 ++++++++++++++++++++++++
>  drivers/firmware/arm_scmi/driver.c  | 26 +++++++++++++++++++++++++-
>  drivers/firmware/arm_scmi/perf.c    |  7 +------
>  drivers/firmware/arm_scmi/power.c   |  7 +------
>  drivers/firmware/arm_scmi/reset.c   |  7 +------
>  drivers/firmware/arm_scmi/sensors.c |  7 +------
>  include/linux/scmi_protocol.h       |  2 +-
>  12 files changed, 62 insertions(+), 39 deletions(-)
> 
> -- 
> 2.17.1
>