lkml.org 
[lkml]   [2021]   [Sep]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v5 09/13] firmware: arm_scmi: Add atomic mode support to virtio transport
Date
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(+)

diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig
index 62517417848b..0bea0c4d9db1 100644
--- a/drivers/firmware/arm_scmi/Kconfig
+++ b/drivers/firmware/arm_scmi/Kconfig
@@ -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
diff --git a/drivers/firmware/arm_scmi/virtio.c b/drivers/firmware/arm_scmi/virtio.c
index 8941bb40f2df..fb3c2760ed42 100644
--- a/drivers/firmware/arm_scmi/virtio.c
+++ b/drivers/firmware/arm_scmi/virtio.c
@@ -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),
};
--
2.17.1
\
 
 \ /
  Last update: 2021-09-23 16:59    [W:0.046 / U:0.388 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site