From db8f0b8088865150e4c9a8b8ffc9abdfd58bc4f7 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 7 Oct 2024 16:54:13 -0700 Subject: [PATCH] firmware: arm_scmi: Give SMC transport precedence over mailbox Broadcom STB platforms have for historical reasons included both "arm,scmi-smc" and "arm,scmi" in their SCMI Device Tree node compatible string, in that order. After the commit b53515fa177c ("firmware: arm_scmi: Make MBOX transport a standalone driver") and with a kernel configuration that enables both the SMC and the mailbox transports, we would probe the mailbox transport, but fail to complete since we would not have a mailbox driver available. With each SCMI transport being a platform driver with its own set of compatible strings to match, rather than an unique platform driver entry point, we no longer match from most specific to least specific. There is also no simple way for the mailbox driver to return -ENODEV and let another platform driver attempt probing. This leads to a platform with no SCMI provider, therefore all drivers depending upon SCMI resources are put on deferred probe forever. By keeping the SMC transport objects linked first, we can let the platform driver match the compatible string and probe successfully with no adverse effects on platforms using the mailbox transport. This is just the workaround to the issue observed which doesn't have any impact on the other platforms. Fixes: b53515fa177c ("firmware: arm_scmi: Make MBOX transport a standalone driver") Signed-off-by: Florian Fainelli Message-Id: <20241007235413.507860-1-florian.fainelli@broadcom.com> Reviewed-by: Cristian Marussi Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/transports/Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/arm_scmi/transports/Makefile b/drivers/firmware/arm_scmi/transports/Makefile index 362a406f08e6..3ba3d3bee151 100644 --- a/drivers/firmware/arm_scmi/transports/Makefile +++ b/drivers/firmware/arm_scmi/transports/Makefile @@ -1,8 +1,10 @@ # SPDX-License-Identifier: GPL-2.0-only -scmi_transport_mailbox-objs := mailbox.o -obj-$(CONFIG_ARM_SCMI_TRANSPORT_MAILBOX) += scmi_transport_mailbox.o +# Keep before scmi_transport_mailbox.o to allow precedence +# while matching the compatible. scmi_transport_smc-objs := smc.o obj-$(CONFIG_ARM_SCMI_TRANSPORT_SMC) += scmi_transport_smc.o +scmi_transport_mailbox-objs := mailbox.o +obj-$(CONFIG_ARM_SCMI_TRANSPORT_MAILBOX) += scmi_transport_mailbox.o scmi_transport_optee-objs := optee.o obj-$(CONFIG_ARM_SCMI_TRANSPORT_OPTEE) += scmi_transport_optee.o scmi_transport_virtio-objs := virtio.o