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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>
96 lines
3.0 KiB
Plaintext
96 lines
3.0 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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menu "ARM System Control and Management Interface Protocol"
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config ARM_SCMI_PROTOCOL
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tristate "ARM System Control and Management Interface (SCMI) Message Protocol"
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depends on ARM || ARM64 || COMPILE_TEST
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help
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ARM System Control and Management Interface (SCMI) protocol is a
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set of operating system-independent software interfaces that are
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used in system management. SCMI is extensible and currently provides
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interfaces for: Discovery and self-description of the interfaces
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it supports, Power domain management which is the ability to place
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a given device or domain into the various power-saving states that
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it supports, Performance management which is the ability to control
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the performance of a domain that is composed of compute engines
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such as application processors and other accelerators, Clock
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management which is the ability to set and inquire rates on platform
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managed clocks and Sensor management which is the ability to read
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sensor data, and be notified of sensor value.
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This protocol library provides interface for all the client drivers
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making use of the features offered by the SCMI.
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if ARM_SCMI_PROTOCOL
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config ARM_SCMI_HAVE_TRANSPORT
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bool
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help
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This declares whether at least one SCMI transport has been configured.
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Used to trigger a build bug when trying to build SCMI without any
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configured transport.
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config ARM_SCMI_HAVE_SHMEM
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bool
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help
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This declares whether a shared memory based transport for SCMI is
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available.
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config ARM_SCMI_HAVE_MSG
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bool
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help
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This declares whether a message passing based transport for SCMI is
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available.
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config ARM_SCMI_TRANSPORT_MAILBOX
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bool "SCMI transport based on Mailbox"
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depends on MAILBOX
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select ARM_SCMI_HAVE_TRANSPORT
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select ARM_SCMI_HAVE_SHMEM
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default y
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help
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Enable mailbox based transport for SCMI.
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If you want the ARM SCMI PROTOCOL stack to include support for a
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transport based on mailboxes, answer Y.
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config ARM_SCMI_TRANSPORT_SMC
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bool "SCMI transport based on SMC"
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depends on HAVE_ARM_SMCCC_DISCOVERY
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select ARM_SCMI_HAVE_TRANSPORT
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select ARM_SCMI_HAVE_SHMEM
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default y
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help
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Enable SMC based transport for SCMI.
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If you want the ARM SCMI PROTOCOL stack to include support for a
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transport based on SMC, answer Y.
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config ARM_SCMI_TRANSPORT_VIRTIO
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bool "SCMI transport based on VirtIO"
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depends on VIRTIO
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select ARM_SCMI_HAVE_TRANSPORT
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select ARM_SCMI_HAVE_MSG
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help
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This enables the virtio based transport for SCMI.
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If you want the ARM SCMI PROTOCOL stack to include support for a
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transport based on VirtIO, answer Y.
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endif #ARM_SCMI_PROTOCOL
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config ARM_SCMI_POWER_DOMAIN
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tristate "SCMI power domain driver"
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depends on ARM_SCMI_PROTOCOL || (COMPILE_TEST && OF)
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default y
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select PM_GENERIC_DOMAINS if PM
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help
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This enables support for the SCMI power domains which can be
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enabled or disabled via the SCP firmware
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This driver can also be built as a module. If so, the module
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will be called scmi_pm_domain. Note this may needed early in boot
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before rootfs may be available.
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endmenu
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