@@ -87,6 +87,20 @@ config ARM_SCMI_TRANSPORT_VIRTIO
If you want the ARM SCMI PROTOCOL stack to include support for a
transport based on VirtIO, answer Y.
+config ARM_SCMI_TRANSPORT_VIRTIO_ATOMIC_ENABLE
+ bool "Enable atomic mode for SCMI VirtIO transport"
+ depends on ARM_SCMI_TRANSPORT_VIRTIO
+ help
+ Enable atomic mode of operation for SCMI VirtIO based transport.
+
+ If you want the SCMI VirtIO based transport to operate in atomic
+ mode, avoiding any kind of sleeping behaviour on the TX path, both
+ by the transport and by the SCMI core, answer Y.
+ Enabling atomic mode operations allows any SCMI driver using this
+ transport to operate in atomic context too, at the price of using
+ a number of busy-waiting primitives all over instead.
+ If unsure say N.
+
endif #ARM_SCMI_PROTOCOL
config ARM_SCMI_POWER_DOMAIN
@@ -488,4 +488,6 @@ const struct scmi_desc scmi_virtio_desc = {
.max_rx_timeout_ms = 60000, /* for non-realtime virtio devices */
.max_msg = 0, /* overridden by virtio_get_max_msg() */
.max_msg_size = VIRTIO_SCMI_MAX_MSG_SIZE,
+ .atomic_capable = true,
+ .atomic_enabled = IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_VIRTIO_ATOMIC_ENABLE),
};
SCMI virtio transport support does not contain any sleeping pattern, so declare it as .atomic_capable. Add a Kernel configuration option to enable SCMI VirtIO transport atomic mode operation and leave it as default disabled. Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> --- v4 --> v5 - add CONFIG_ARM_SCMI_TRANSPORT_VIRTIO_ATOMIC_ENABLE - reviewed commit message --- drivers/firmware/arm_scmi/Kconfig | 14 ++++++++++++++ drivers/firmware/arm_scmi/virtio.c | 2 ++ 2 files changed, 16 insertions(+)