[PATCH v4 4/8] gpu: nova-core: gsp: expose GSP-RM internal client and subdevice handles

[Eliot Courtney <ecourtney@nvidia.com>]

Expose the `hInternalClient` and `hInternalSubdevice` handles. These are
needed for RM control calls.

Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
---
 drivers/gpu/nova-core/gsp/commands.rs    | 65 ++++++++++++++++++++++++++++++++
 drivers/gpu/nova-core/gsp/fw/commands.rs | 19 +++++++++-
 2 files changed, 83 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index b8f64bfe9313..8a19ef689731 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -4,6 +4,7 @@
     array,
     convert::Infallible,
     ffi::FromBytesUntilNulError,
+    marker::PhantomData,
     str::Utf8Error, //
 };
 
@@ -35,6 +36,54 @@
     sbuffer::SBufferIter,
 };
 
+/// Marker type for a GSP-RM client handle.
+///
+/// A client handle identifies a client which provides a namespace for RM objects. Lookup of objects
+/// happens within the client namespace.
+pub(crate) struct Client;
+
+/// Marker type for a GSP-RM device handle.
+///
+/// A device handle identifies a logical GPU device instance under a client. In multi-GPU
+/// configurations it can represent a grouped or logical device.
+#[expect(dead_code)]
+pub(crate) struct Device;
+
+/// Marker type for a GSP-RM subdevice handle.
+///
+/// A subdevice handle identifies a child of a device that selects one specific GPU within that
+/// device.
+pub(crate) struct Subdevice;
+
+/// A typed GSP-RM object handle.
+///
+/// These handles form a tree structure with different types of RM objects, with client at the root.
+/// An RM object is anything identified by a valid handle. For example, the tree may look like
+/// Client -> Device -> Subdevice, where there may be multiple devices under each client, and
+/// multiple subdevices under each device.
+#[derive(Debug)]
+pub(crate) struct Handle<T>(u32, PhantomData<T>);
+
+impl<T> Clone for Handle<T> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+impl<T> Copy for Handle<T> {}
+
+impl<T> Handle<T> {
+    /// Creates a new handle from a raw value.
+    pub(crate) fn new(raw: u32) -> Self {
+        Self(raw, PhantomData)
+    }
+
+    /// Returns the raw handle value.
+    #[expect(dead_code)]
+    pub(crate) fn as_raw(self) -> u32 {
+        self.0
+    }
+}
+
 /// The `GspSetSystemInfo` command.
 pub(crate) struct SetSystemInfo<'a> {
     pdev: &'a pci::Device<device::Bound>,
@@ -193,6 +242,8 @@ fn init(&self) -> impl Init<Self::Command, Self::InitError> {
 /// The reply from the GSP to the [`GetGspInfo`] command.
 pub(crate) struct GetGspStaticInfoReply {
     gpu_name: [u8; 64],
+    client: Handle<Client>,
+    subdevice: Handle<Subdevice>,
 }
 
 impl MessageFromGsp for GetGspStaticInfoReply {
@@ -206,6 +257,8 @@ fn read(
     ) -> Result<Self, Self::InitError> {
         Ok(GetGspStaticInfoReply {
             gpu_name: msg.gpu_name_str(),
+            client: msg.client(),
+            subdevice: msg.subdevice(),
         })
     }
 }
@@ -232,6 +285,18 @@ pub(crate) fn gpu_name(&self) -> core::result::Result<&str, GpuNameError> {
             .to_str()
             .map_err(GpuNameError::InvalidUtf8)
     }
+
+    /// Returns the client handle allocated by GSP-RM.
+    #[expect(dead_code)]
+    pub(crate) fn client(&self) -> Handle<Client> {
+        self.client
+    }
+
+    /// Returns the subdevice handle allocated by GSP-RM.
+    #[expect(dead_code)]
+    pub(crate) fn subdevice(&self) -> Handle<Subdevice> {
+        self.subdevice
+    }
 }
 
 /// Send the [`GetGspInfo`] command and awaits for its reply.
diff --git a/drivers/gpu/nova-core/gsp/fw/commands.rs b/drivers/gpu/nova-core/gsp/fw/commands.rs
index db46276430be..9fce6ffefbce 100644
--- a/drivers/gpu/nova-core/gsp/fw/commands.rs
+++ b/drivers/gpu/nova-core/gsp/fw/commands.rs
@@ -10,7 +10,14 @@
     }, //
 };
 
-use crate::gsp::GSP_PAGE_SIZE;
+use crate::gsp::{
+    commands::{
+        Client,
+        Handle,
+        Subdevice, //
+    },
+    GSP_PAGE_SIZE, //
+};
 
 use super::bindings;
 
@@ -121,6 +128,16 @@ impl GspStaticConfigInfo {
     pub(crate) fn gpu_name_str(&self) -> [u8; 64] {
         self.0.gpuNameString
     }
+
+    /// Returns the client handle allocated by GSP-RM.
+    pub(crate) fn client(&self) -> Handle<Client> {
+        Handle::new(self.0.hInternalClient)
+    }
+
+    /// Returns the subdevice handle allocated by GSP-RM.
+    pub(crate) fn subdevice(&self) -> Handle<Subdevice> {
+        Handle::new(self.0.hInternalSubdevice)
+    }
 }
 
 // SAFETY: Padding is explicit and will not contain uninitialized data.

-- 
2.53.0