[PATCH v3 7/9] gpu: nova-core: gsp: add RM control command infrastructure

Eliot Courtney
2026-03-25T12:14:22Z

Add `RawRmControl` which implements CommandToGsp for sending RM control
RPCs. Add `RmControlReply` which implements MessageFromGsp for getting
the reply back. Add the `RmControlCommand` trait for defining an RM
control message.

Add `RmControl` which sends an RM control RPC via the command queue
using the above structures.

This gives a generic way to send each RM control RPC. Each new RM
control RPC can be added by extending RmControlMsgFunction, adding its
bindings wrappers and writing an implementation of `RmControlCommand`
that can be sent using `RmControl`.

Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
---
drivers/gpu/nova-core/gsp.rs | 1 +
drivers/gpu/nova-core/gsp/fw/rm.rs | 1 -
drivers/gpu/nova-core/gsp/rm.rs | 3 +
drivers/gpu/nova-core/gsp/rm/commands.rs | 141 +++++++++++++++++++++++++++++++
4 files changed, 145 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/nova-core/gsp.rs b/drivers/gpu/nova-core/gsp.rs
index 04e3976127cc..09d6e673aa65 100644
--- a/drivers/gpu/nova-core/gsp.rs
+++ b/drivers/gpu/nova-core/gsp.rs
@@ -21,6 +21,7 @@
pub(crate) mod cmdq;
pub(crate) mod commands;
mod fw;
+pub(crate) mod rm;
mod sequencer;

pub(crate) use fw::{
diff --git a/drivers/gpu/nova-core/gsp/fw/rm.rs b/drivers/gpu/nova-core/gsp/fw/rm.rs
index 4a4f97d88ecf..1c6e8b4c4865 100644
--- a/drivers/gpu/nova-core/gsp/fw/rm.rs
+++ b/drivers/gpu/nova-core/gsp/fw/rm.rs
@@ -53,7 +53,6 @@ pub(crate) struct GspRmControl {
inner: bindings::rpc_gsp_rm_control_v03_00,
}

-#[expect(dead_code)]
impl GspRmControl {
/// Creates a new RM control command.
pub(crate) fn new<T>(
diff --git a/drivers/gpu/nova-core/gsp/rm.rs b/drivers/gpu/nova-core/gsp/rm.rs
new file mode 100644
index 000000000000..10e879a3e842
--- /dev/null
+++ b/drivers/gpu/nova-core/gsp/rm.rs
@@ -0,0 +1,3 @@
+// SPDX-License-Identifier: GPL-2.0
+
+pub(crate) mod commands;
diff --git a/drivers/gpu/nova-core/gsp/rm/commands.rs b/drivers/gpu/nova-core/gsp/rm/commands.rs
new file mode 100644
index 000000000000..8845ca0a0225
--- /dev/null
+++ b/drivers/gpu/nova-core/gsp/rm/commands.rs
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::array;
+
+use kernel::prelude::*;
+
+use crate::{
+ driver::Bar0,
+ gsp::{
+ cmdq::{
+ Cmdq,
+ CommandToGsp,
+ MessageFromGsp, //
+ },
+ commands::{
+ Client,
+ Handle, //
+ },
+ fw::{
+ rm::*,
+ MsgFunction,
+ NvStatus, //
+ },
+ },
+ sbuffer::SBufferIter, //
+};
+
+/// Wraps a [`RmControl`] command to provide the infrastructure for sending it on the command queue.
+struct RawRmControl<'a, T>(&'a RmControl<T>)
+where
+ T: RmControlCommand;
+
+impl<'a, T: RmControlCommand> CommandToGsp for RawRmControl<'a, T> {
+ const FUNCTION: MsgFunction = MsgFunction::GspRmControl;
+ type Command = GspRmControl;
+ type Reply = RmControlReply;
+ type InitError = Error;
+
+ fn init(&self) -> impl Init<Self::Command, Self::InitError> {
+ let params_size: u32 = T::LEN.try_into()?;
+ Ok(GspRmControl::new(
+ self.0.client,
+ self.0.object,
+ T::FUNCTION,
+ params_size,
+ ))
+ }
+
+ fn variable_payload_len(&self) -> usize {
+ T::LEN
+ }
+
+ fn init_variable_payload(
+ &self,
+ dst: &mut SBufferIter<array::IntoIter<&mut [u8], 2>>,
+ ) -> Result {
+ self.0.cmd.write_payload(dst)
+ }
+}
+
+/// Command for sending an RM control message to the GSP.
+///
+/// RM control messages are used to query or control RM objects (see [`Handle`] for more info on RM
+/// objects). It takes a client handle and an RM object handle identifying the target of the
+/// message, within the given client.
+pub(crate) struct RmControl<T>
+where
+ T: RmControlCommand,
+{
+ /// The client handle under which `object` is allocated.
+ client: Handle<Client>,
+ /// The RM object handle to query or control.
+ object: Handle<T::Target>,
+ /// The specific RM control command to send.
+ cmd: T,
+}
+
+#[expect(unused)]
+impl<T: RmControlCommand> RmControl<T> {
+ /// Creates a new RM control command.
+ pub(crate) fn new(client: Handle<Client>, object: Handle<T::Target>, cmd: T) -> Self {
+ Self {
+ client,
+ object,
+ cmd,
+ }
+ }
+
+ /// Sends an RM control command, checks the reply status, and returns the reply.
+ pub(crate) fn send(self, cmdq: &Cmdq, bar: &Bar0) -> Result<T::Reply> {
+ let reply = cmdq.send_command(bar, RawRmControl(&self))?;
+
+ Result::from(reply.status)?;
+
+ self.cmd.parse_reply(&reply.params)
+ }
+}
+
+/// Response from an RM control message.
+struct RmControlReply {
+ status: NvStatus,
+ params: KVVec<u8>,
+}
+
+impl MessageFromGsp for RmControlReply {
+ const FUNCTION: MsgFunction = MsgFunction::GspRmControl;
+ type Message = GspRmControl;
+ type InitError = Error;
+
+ fn read(
+ msg: &Self::Message,
+ sbuffer: &mut SBufferIter<array::IntoIter<&[u8], 2>>,
+ ) -> Result<Self, Self::InitError> {
+ Ok(RmControlReply {
+ status: msg.status(),
+ params: sbuffer.read_to_vec(GFP_KERNEL)?,
+ })
+ }
+}
+
+/// Trait for RM control commands that can be sent using [`RmControl`].
+pub(crate) trait RmControlCommand {
+ /// The specific RM control message kind to send.
+ const FUNCTION: RmControlMsgFunction;
+
+ /// Length of the command-specific payload to send with the RM control message.
+ const LEN: usize;
+
+ /// The type of the reply after parsing the raw bytes from the RM control reply message.
+ type Reply;
+
+ /// The type of the RM object that this command targets.
+ type Target;
+
+ /// Writes the payload of the command into `dst`.
+ fn write_payload(&self, dst: &mut SBufferIter<array::IntoIter<&mut [u8], 2>>) -> Result;
+
+ /// Parses the reply bytes from an RM control reply message into the command-specific
+ /// reply type.
+ fn parse_reply(&self, params: &[u8]) -> Result<Self::Reply>;
+}

--
2.53.0