Re: [PATCH v4 06/16] firmware: arm_scmi, smccc, mailbox: Make shmem based transports optional

[Peter Hilber]

On 11.06.21 18:59, Cristian Marussi wrote:
> From: Igor Skalkin <igor.skalkin@xxxxxxxxxxxxxxx>
>
> Upon adding the virtio transport in this patch series, SCMI will also
> work without shared memory based transports. Also, the mailbox transport
> may not be needed if the smc transport is used.
>
> - Compile shmem.c only if a shmem based transport is available.
>
> - Remove hard dependency of SCMI on mailbox.

The hard dependency has now already been removed with

  c05b07963e96 ("firmware: arm_scmi: Add SMCCC discovery dependency in")

> [ Peter: Adapted patch for submission to upstream. ]
>
> Co-developed-by: Peter Hilber <peter.hilber@xxxxxxxxxxxxxxx>
> Signed-off-by: Igor Skalkin <igor.skalkin@xxxxxxxxxxxxxxx>
> Signed-off-by: Peter Hilber <peter.hilber@xxxxxxxxxxxxxxx>
> ---
>  drivers/firmware/Kconfig           | 8 +++++++-
>  drivers/firmware/arm_scmi/Makefile | 2 +-
>  drivers/firmware/arm_scmi/common.h | 2 ++
>  drivers/firmware/smccc/Kconfig     | 1 +
>  drivers/mailbox/Kconfig            | 1 +
>  5 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
> index 1db738d5b301..358f895847b5 100644
> --- a/drivers/firmware/Kconfig
> +++ b/drivers/firmware/Kconfig
> @@ -9,7 +9,7 @@ menu "Firmware Drivers"
>  config ARM_SCMI_PROTOCOL
>  	tristate "ARM System Control and Management Interface (SCMI) Message Protocol"
>  	depends on ARM || ARM64 || COMPILE_TEST
> -	depends on MAILBOX || HAVE_ARM_SMCCC_DISCOVERY
> +	depends on ARM_SCMI_HAVE_SHMEM
>  	help
>  	  ARM System Control and Management Interface (SCMI) protocol is a
>  	  set of operating system-independent software interfaces that are
> @@ -27,6 +27,12 @@ config ARM_SCMI_PROTOCOL
>  	  This protocol library provides interface for all the client drivers
>  	  making use of the features offered by the SCMI.
>  
> +config ARM_SCMI_HAVE_SHMEM
> +	bool
> +	help
> +	  This declares whether a shared memory based transport for SCMI is
> +	  available.
> +
>  config ARM_SCMI_POWER_DOMAIN
>  	tristate "SCMI power domain driver"
>  	depends on ARM_SCMI_PROTOCOL || (COMPILE_TEST && OF)
> diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
> index 6a2ef63306d6..5a2d4c32e0ae 100644
> --- a/drivers/firmware/arm_scmi/Makefile
> +++ b/drivers/firmware/arm_scmi/Makefile
> @@ -1,7 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  scmi-bus-y = bus.o
>  scmi-driver-y = driver.o notify.o
> -scmi-transport-y = shmem.o
> +scmi-transport-$(CONFIG_ARM_SCMI_HAVE_SHMEM) = shmem.o
>  scmi-transport-$(CONFIG_MAILBOX) += mailbox.o
>  scmi-transport-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY) += smc.o
>  scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o voltage.o
> diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
> index 0edc04bc434c..4666777019fa 100644
> --- a/drivers/firmware/arm_scmi/common.h
> +++ b/drivers/firmware/arm_scmi/common.h
> @@ -375,7 +375,9 @@ struct scmi_desc {
>  	bool support_xfers_delegation;
>  };
>  
> +#ifdef CONFIG_MAILBOX
>  extern const struct scmi_desc scmi_mailbox_desc;
> +#endif
>  #ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY
>  extern const struct scmi_desc scmi_smc_desc;
>  #endif
> diff --git a/drivers/firmware/smccc/Kconfig b/drivers/firmware/smccc/Kconfig
> index 15e7466179a6..69c4d6cabf62 100644
> --- a/drivers/firmware/smccc/Kconfig
> +++ b/drivers/firmware/smccc/Kconfig
> @@ -9,6 +9,7 @@ config HAVE_ARM_SMCCC_DISCOVERY
>  	bool
>  	depends on ARM_PSCI_FW
>  	default y
> +	select ARM_SCMI_HAVE_SHMEM
>  	help
>  	 SMCCC v1.0 lacked discoverability and hence PSCI v1.0 was updated
>  	 to add SMCCC discovery mechanism though the PSCI firmware
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index 68de2c6af727..fc02c38c0739 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  menuconfig MAILBOX
>  	bool "Mailbox Hardware Support"
> +	select ARM_SCMI_HAVE_SHMEM
>  	help
>  	  Mailbox is a framework to control hardware communication between
>  	  on-chip processors through queued messages and interrupt driven