[PATCH v3 4/7] drm: nova: Add GETPARAM parameter to read the GPU chipid

[Alistair Popple <apopple@nvidia.com>]

One of the first things a user needs to know about a GPU is its chipid,
so add a GETPARAM parameter to return that.

Signed-off-by: Alistair Popple <apopple@nvidia.com>

---

Changes since v2:

 - Split out enum definition into its own patch
 - Change uAPI to use chipid rather than chipset

Changes since v1:

 - Vertical import
 - Use a single enum for chipset values
---
 drivers/gpu/drm/nova/driver.rs |  1 -
 drivers/gpu/drm/nova/file.rs   |  3 ++-
 drivers/gpu/nova-core/api.rs   | 11 +++++++++--
 drivers/gpu/nova-core/gpu.rs   | 10 +++++-----
 include/uapi/drm/nova_drm.h    |  7 +++++++
 5 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/nova/driver.rs b/drivers/gpu/drm/nova/driver.rs
index 632137d1c6d7..f144417b29c9 100644
--- a/drivers/gpu/drm/nova/driver.rs
+++ b/drivers/gpu/drm/nova/driver.rs
@@ -32,7 +32,6 @@ pub(crate) struct Nova<'bound> {
 
 /// DRM registration data, accessible from ioctl handlers via the registration guard.
 pub(crate) struct DrmRegData<'bound> {
-    #[expect(unused)]
     pub(crate) api: Pin<&'bound NovaCoreApi<'bound>>,
 }
 
diff --git a/drivers/gpu/drm/nova/file.rs b/drivers/gpu/drm/nova/file.rs
index 1156df51c533..855f23877734 100644
--- a/drivers/gpu/drm/nova/file.rs
+++ b/drivers/gpu/drm/nova/file.rs
@@ -34,7 +34,7 @@ impl File {
     /// IOCTL: get_param: Query GPU / driver metadata.
     pub(crate) fn get_param(
         dev: &NovaDevice<Registered>,
-        _reg_data: &DrmRegData<'_>,
+        reg_data: &DrmRegData<'_>,
         getparam: &mut uapi::drm_nova_getparam,
         _file: &drm::File<File>,
     ) -> Result<u32> {
@@ -43,6 +43,7 @@ pub(crate) fn get_param(
 
         let value = match getparam.param as u32 {
             uapi::NOVA_GETPARAM_VRAM_BAR_SIZE => pdev.resource_len(1)?,
+            uapi::NOVA_GETPARAM_GPU_CHIPID => reg_data.api.chipset() as u64,
             _ => return Err(EINVAL),
         };
 
diff --git a/drivers/gpu/nova-core/api.rs b/drivers/gpu/nova-core/api.rs
index 610cfc01111e..09da0b4e9103 100644
--- a/drivers/gpu/nova-core/api.rs
+++ b/drivers/gpu/nova-core/api.rs
@@ -12,11 +12,13 @@
     types::CovariantForLt, //
 };
 
-use crate::gpu::Gpu;
+use crate::gpu::{
+    Chipset,
+    Gpu, //
+};
 
 /// API handle for the auxiliary bus child drivers to interact with nova-core.
 pub struct NovaCoreApi<'bound> {
-    #[expect(unused)]
     pub(crate) gpu: Pin<&'bound Gpu<'bound>>,
 }
 
@@ -26,4 +28,9 @@ impl NovaCoreApi<'_> {
     pub fn of(adev: &auxiliary::Device<Bound>) -> Result<Pin<&NovaCoreApi<'_>>> {
         adev.registration_data::<CovariantForLt!(NovaCoreApi<'_>)>()
     }
+
+    /// Returns the chipset of this GPU.
+    pub fn chipset(&self) -> Chipset {
+        self.gpu.spec.chipset
+    }
 }
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 738a590e753b..264fe4e65b3f 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -41,7 +41,7 @@ macro_rules! define_chipset {
         ::kernel::macros::paste!(
         /// Enum representation of the GPU chipset.
         #[derive(fmt::Debug, Copy, Clone, PartialOrd, Ord, PartialEq, Eq)]
-        pub(crate) enum Chipset {
+        pub enum Chipset {
             $($variant = uapi::[<drm_nova_chipid_NOVA_DRM_CHIPID_ $variant:upper>] as isize),*,
         }
 
@@ -119,7 +119,7 @@ fn try_from(value: u32) -> Result<Self, Self::Error> {
 });
 
 impl Chipset {
-    pub(crate) const fn arch(self) -> Architecture {
+    pub const fn arch(self) -> Architecture {
         match self {
             Self::TU102 | Self::TU104 | Self::TU106 | Self::TU117 | Self::TU116 => {
                 Architecture::Turing
@@ -161,7 +161,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 bounded_enum! {
     /// Enum representation of the GPU generation.
     #[derive(fmt::Debug, Copy, Clone)]
-    pub(crate) enum Architecture with TryFrom<Bounded<u32, 6>> {
+    pub enum Architecture with TryFrom<Bounded<u32, 6>> {
         Turing = 0x16,
         Ampere = 0x17,
         Hopper = 0x18,
@@ -195,7 +195,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 /// Structure holding a basic description of the GPU: `Chipset` and `Revision`.
 #[derive(Clone, Copy)]
 pub(crate) struct Spec {
-    chipset: Chipset,
+    pub(crate) chipset: Chipset,
     revision: Revision,
 }
 
@@ -281,7 +281,7 @@ struct GspResources<'gpu> {
 /// Structure holding the resources required to operate the GPU.
 #[pin_data]
 pub(crate) struct Gpu<'gpu> {
-    spec: Spec,
+    pub(crate) spec: Spec,
     /// Static GPU information as provided by the GSP.
     gsp_static_info: GetGspStaticInfoReply,
     /// GSP and its resources.
diff --git a/include/uapi/drm/nova_drm.h b/include/uapi/drm/nova_drm.h
index cb13fba6b952..c655302a40fd 100644
--- a/include/uapi/drm/nova_drm.h
+++ b/include/uapi/drm/nova_drm.h
@@ -25,6 +25,13 @@ extern "C" {
  */
 #define NOVA_GETPARAM_VRAM_BAR_SIZE	0x1
 
+/*
+ * NOVA_GETPARAM_GPU_CHIPID
+ *
+ * Query the GPU chipid (architecture/implementation).
+ */
+#define NOVA_GETPARAM_GPU_CHIPID	0x2
+
 enum drm_nova_chipid {
 	/* Turing */
 	NOVA_DRM_CHIPID_TU102 = 0x162,
-- 
2.54.0