Add `RmControlMsgFunction` which mirrors `MsgFunction` in fw.rs. This
denotes the type of RM control RPC. For now it contains a single
discriminant only (which will be used later), which is needed to prevent
compile errors when using an otherwise empty enum.

Add `GspRmControl` which wraps the RM control RPC structure from the
bindings.

Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
---
 drivers/gpu/nova-core/gsp/fw.rs                   |  1 +
 drivers/gpu/nova-core/gsp/fw/r570_144/bindings.rs |  1 +
 drivers/gpu/nova-core/gsp/fw/rm.rs                | 82 +++++++++++++++++++++++
 3 files changed, 84 insertions(+)

diff --git a/drivers/gpu/nova-core/gsp/fw.rs b/drivers/gpu/nova-core/gsp/fw.rs
index c71c45462efd..0796e6c0baf2 100644
--- a/drivers/gpu/nova-core/gsp/fw.rs
+++ b/drivers/gpu/nova-core/gsp/fw.rs
@@ -2,6 +2,7 @@
 
 pub(crate) mod commands;
 mod r570_144;
+pub(crate) mod rm;
 
 // Alias to avoid repeating the version number with every use.
 use r570_144 as bindings;
diff --git a/drivers/gpu/nova-core/gsp/fw/r570_144/bindings.rs b/drivers/gpu/nova-core/gsp/fw/r570_144/bindings.rs
index 05e205e6dc58..ece31cc32f5b 100644
--- a/drivers/gpu/nova-core/gsp/fw/r570_144/bindings.rs
+++ b/drivers/gpu/nova-core/gsp/fw/r570_144/bindings.rs
@@ -44,6 +44,7 @@ fn fmt(&self, fmt: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
 pub const GSP_FW_WPR_META_MAGIC: i64 = -2577556379034558285;
 pub const REGISTRY_TABLE_ENTRY_TYPE_DWORD: u32 = 1;
 pub const GSP_MSG_QUEUE_ELEMENT_SIZE_MAX: u32 = 65536;
+pub const NV2080_CTRL_CMD_CE_GET_FAULT_METHOD_BUFFER_SIZE: u32 = 545270280;
 pub type __u8 = ffi::c_uchar;
 pub type __u16 = ffi::c_ushort;
 pub type __u32 = ffi::c_uint;
diff --git a/drivers/gpu/nova-core/gsp/fw/rm.rs b/drivers/gpu/nova-core/gsp/fw/rm.rs
new file mode 100644
index 000000000000..8bb7b11736b9
--- /dev/null
+++ b/drivers/gpu/nova-core/gsp/fw/rm.rs
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use kernel::{
+    prelude::*,
+    transmute::{
+        AsBytes,
+        FromBytes, //
+    }, //
+};
+
+use super::{
+    bindings,
+    NvStatus, //
+};
+
+/// Command code for RM control RPCs sent using [`MsgFunction::GspRmControl`].
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(u32)]
+pub(crate) enum RmControlMsgFunction {
+    /// Get the CE fault method buffer size.
+    CeGetFaultMethodBufferSize = bindings::NV2080_CTRL_CMD_CE_GET_FAULT_METHOD_BUFFER_SIZE,
+}
+
+impl TryFrom<u32> for RmControlMsgFunction {
+    type Error = kernel::error::Error;
+
+    fn try_from(value: u32) -> Result<Self> {
+        match value {
+            bindings::NV2080_CTRL_CMD_CE_GET_FAULT_METHOD_BUFFER_SIZE => {
+                Ok(Self::CeGetFaultMethodBufferSize)
+            }
+            _ => Err(EINVAL),
+        }
+    }
+}
+
+impl From<RmControlMsgFunction> for u32 {
+    fn from(value: RmControlMsgFunction) -> Self {
+        // CAST: `RmControlMsgFunction` is `repr(u32)` and can thus be cast losslessly.
+        value as u32
+    }
+}
+
+/// RM control message element structure.
+#[derive(Zeroable)]
+#[repr(transparent)]
+pub(crate) struct GspRmControl {
+    inner: bindings::rpc_gsp_rm_control_v03_00,
+}
+
+impl GspRmControl {
+    /// Creates a new RM control command.
+    pub(crate) fn new(
+        h_client: u32,
+        h_object: u32,
+        cmd: RmControlMsgFunction,
+        params_size: u32,
+    ) -> Self {
+        Self {
+            inner: bindings::rpc_gsp_rm_control_v03_00 {
+                hClient: h_client,
+                hObject: h_object,
+                cmd: u32::from(cmd),
+                status: 0,
+                paramsSize: params_size,
+                flags: 0,
+                params: Default::default(),
+            },
+        }
+    }
+
+    /// Returns the status from the RM control response.
+    pub(crate) fn status(&self) -> NvStatus {
+        NvStatus::from(self.inner.status)
+    }
+}
+
+// SAFETY: This struct only contains integer types for which all bit patterns are valid.
+unsafe impl FromBytes for GspRmControl {}
+
+// SAFETY: This struct contains no padding.
+unsafe impl AsBytes for GspRmControl {}

-- 
2.53.0

On Fri, 27 Feb 2026, Eliot Courtney wrote:
[..]
> +/// Command code for RM control RPCs sent using [`MsgFunction::GspRmControl`].
> +#[derive(Copy, Clone, Debug, PartialEq)]
> +#[repr(u32)]
> +pub(crate) enum RmControlMsgFunction {
> +    /// Get the CE fault method buffer size.
> +    CeGetFaultMethodBufferSize = bindings::NV2080_CTRL_CMD_CE_GET_FAULT_METHOD_BUFFER_SIZE,
> +}
> +
> +impl TryFrom<u32> for RmControlMsgFunction {
> +    type Error = kernel::error::Error;
> +
> +    fn try_from(value: u32) -> Result<Self> {

Other similar impls in the driver carry a TODO[FPRI] comment. Please add one
above this impl:

// TODO[FPRI]: replace with `FromPrimitive`.

> +        match value {
> +            bindings::NV2080_CTRL_CMD_CE_GET_FAULT_METHOD_BUFFER_SIZE => {
> +                Ok(Self::CeGetFaultMethodBufferSize)
> +            }
> +            _ => Err(EINVAL),
> +        }
> +    }
> +}

Nit: the braces around the single-expression match arm are unnecessary:

    match value {
        bindings::NV2080_CTRL_CMD_CE_GET_FAULT_METHOD_BUFFER_SIZE =>
            Ok(Self::CeGetFaultMethodBufferSize),
        _ => Err(EINVAL),
    }

thanks,

-- 
Joel Fernandes

On Tue Mar 10, 2026 at 6:45 AM JST, Joel Fernandes wrote:
> On Fri, 27 Feb 2026, Eliot Courtney wrote:
> [..]
>> +/// Command code for RM control RPCs sent using [`MsgFunction::GspRmControl`].
>> +#[derive(Copy, Clone, Debug, PartialEq)]
>> +#[repr(u32)]
>> +pub(crate) enum RmControlMsgFunction {
>> +    /// Get the CE fault method buffer size.
>> +    CeGetFaultMethodBufferSize = bindings::NV2080_CTRL_CMD_CE_GET_FAULT_METHOD_BUFFER_SIZE,
>> +}
>> +
>> +impl TryFrom<u32> for RmControlMsgFunction {
>> +    type Error = kernel::error::Error;
>> +
>> +    fn try_from(value: u32) -> Result<Self> {
>
> Other similar impls in the driver carry a TODO[FPRI] comment. Please add one
> above this impl:
>
> // TODO[FPRI]: replace with `FromPrimitive`.
>
>> +        match value {
>> +            bindings::NV2080_CTRL_CMD_CE_GET_FAULT_METHOD_BUFFER_SIZE => {
>> +                Ok(Self::CeGetFaultMethodBufferSize)
>> +            }
>> +            _ => Err(EINVAL),
>> +        }
>> +    }
>> +}

Will do, thanks.

>
> Nit: the braces around the single-expression match arm are unnecessary:
>
>     match value {
>         bindings::NV2080_CTRL_CMD_CE_GET_FAULT_METHOD_BUFFER_SIZE =>
>             Ok(Self::CeGetFaultMethodBufferSize),
>         _ => Err(EINVAL),
>     }
>
> thanks,

This does not pass rustfmtcheck, probably because rustfmt wants braces
on multilines like this.