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| author | Igor Skalkin <igor.skalkin@opensynergy.com> | 2021-08-03 14:10:24 +0100 |
|---|---|---|
| committer | Sudeep Holla <sudeep.holla@arm.com> | 2021-08-05 10:24:08 +0100 |
| commit | 46abe13b5e3db187e52cd0de06c07bbce010726c (patch) | |
| tree | 1b455b3dc24169f900b18a63061da7512198aa10 /drivers/firmware/arm_scmi/Kconfig | |
| parent | 13fba878ccdd15b1c2fdce424995744dc40eaf16 (diff) | |
| download | linux-46abe13b5e3db187e52cd0de06c07bbce010726c.tar.bz2 | |
firmware: arm_scmi: Add virtio transport
This transport enables communications with an SCMI platform through virtio;
the SCMI platform will be represented by a virtio device.
Implement an SCMI virtio driver according to the virtio SCMI device spec
[1]. Virtio device id 32 has been reserved for the SCMI device [2].
The virtio transport has one Tx channel (virtio cmdq, A2P channel) and
at most one Rx channel (virtio eventq, P2A channel).
The following feature bit defined in [1] is not implemented:
VIRTIO_SCMI_F_SHARED_MEMORY.
The number of messages which can be pending simultaneously is restricted
according to the virtqueue capacity negotiated at probing time.
As soon as Rx channel message buffers are allocated or have been read
out by the arm-scmi driver, feed them back to the virtio device.
Since some virtio devices may not have the short response time exhibited
by SCMI platforms using other transports, set a generous response
timeout.
SCMI polling mode is not supported by this virtio transport since deemed
meaningless: polling mode operation is offered by the SCMI core to those
transports that could not provide a completion interrupt on the TX path,
which is never the case for virtio whose core callbacks can easily call
into core scmi_rx_callback upon messages reception.
[1] https://github.com/oasis-tcs/virtio-spec/blob/master/virtio-scmi.tex
[2] https://www.oasis-open.org/committees/ballot.php?id=3496
Link: https://lore.kernel.org/r/20210803131024.40280-16-cristian.marussi@arm.com
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Co-developed-by: Peter Hilber <peter.hilber@opensynergy.com>
Co-developed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Igor Skalkin <igor.skalkin@opensynergy.com>
[ Peter: Adapted patch for submission to upstream. ]
Signed-off-by: Peter Hilber <peter.hilber@opensynergy.com>
[ Cristian: simplified driver logic, changed link_supplier and channel
available/setup logic, removed dummy callbacks ]
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Diffstat (limited to 'drivers/firmware/arm_scmi/Kconfig')
| -rw-r--r-- | drivers/firmware/arm_scmi/Kconfig | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig index 24fed705b02c..7f4d2435503b 100644 --- a/drivers/firmware/arm_scmi/Kconfig +++ b/drivers/firmware/arm_scmi/Kconfig @@ -66,6 +66,17 @@ config ARM_SCMI_TRANSPORT_SMC If you want the ARM SCMI PROTOCOL stack to include support for a transport based on SMC, answer Y. +config ARM_SCMI_TRANSPORT_VIRTIO + bool "SCMI transport based on VirtIO" + depends on VIRTIO + select ARM_SCMI_HAVE_TRANSPORT + select ARM_SCMI_HAVE_MSG + help + This enables the virtio based transport for SCMI. + + If you want the ARM SCMI PROTOCOL stack to include support for a + transport based on VirtIO, answer Y. + endif #ARM_SCMI_PROTOCOL config ARM_SCMI_POWER_DOMAIN |