[RFC PATCH v2 01/10] firmware: arm_scmi, smccc, mailbox: Make shmem based transports optional

From: Peter Hilber
Date: Thu Nov 05 2020 - 16:28:44 EST


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.

Co-developed-by: Peter Hilber <peter.hilber@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Hilber <peter.hilber@xxxxxxxxxxxxxxx>
Signed-off-by: Igor Skalkin <igor.skalkin@xxxxxxxxxxxxxxx>
---
drivers/firmware/Kconfig | 9 ++++++++-
drivers/firmware/arm_scmi/Makefile | 2 +-
drivers/firmware/arm_scmi/common.h | 2 ++
drivers/firmware/arm_scmi/driver.c | 2 ++
drivers/firmware/smccc/Kconfig | 1 +
drivers/mailbox/Kconfig | 1 +
6 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index afdbebba628a..bdde51adb267 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
+ 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 +27,13 @@ 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
+ default n
+ 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 bc0d54f8e861..3cc7fa40a464 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
diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 65063fa948d4..aed192238177 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -242,7 +242,9 @@ struct scmi_desc {
int max_msg_size;
};

+#ifdef CONFIG_MAILBOX
extern const struct scmi_desc scmi_mailbox_desc;
+#endif
#ifdef CONFIG_HAVE_ARM_SMCCC
extern const struct scmi_desc scmi_smc_desc;
#endif
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 3dfd8b6a0ebf..9e2f36127793 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -918,7 +918,9 @@ ATTRIBUTE_GROUPS(versions);

/* Each compatible listed below must have descriptor associated with it */
static const struct of_device_id scmi_of_match[] = {
+#ifdef CONFIG_MAILBOX
{ .compatible = "arm,scmi", .data = &scmi_mailbox_desc },
+#endif
#ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY
{ .compatible = "arm,scmi-smc", .data = &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 05b1009e2820..5ffe1ab0c869 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
--
2.25.1