[PATCH v6 05/13] drm: nova: Add chipid enum to nova-drm UAPI

[Alistair Popple]

The chip identifier uniquely identifies a GPU chip and needs to be
exposed to user-space so it can look up chip specific properties that
cannot be derived from the architecture alone. This adds a public enum
to the userspace headers for each chip ID. Nova-core can then use this
enum to define its chipsets.

The values are opaque to user-space. They may be compared against the
enum to identify a chip but user-space must not assume the values carry
any particular meaning or encoding.

This does create a coupling between nova-drm and nova-core whereby
nova-core depends on the values defined by the user-space API for
nova-drm. However this is entirely appropriate as nova-core must be
bound by the UAPI headers as the enum values are read by nova-core and
passed through to user-space.

Note that nova-core currently refers to the chipid as a chipset. This
isn't ideal given that chipid is the preferred and more accurate term
and is what should be exposed via the uAPI. Therefore a future patch
series will be posted that aligns nova-core internals to using chipid
rather than chipset.

Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
Assisted-by: LLM

---

Changes since v5:

 - Re-added. Following discussion an opaque chipid is exposed alongside
   the architecture in place of the implementation.

Changes since v4:

 - Dropped in favour of exposing architecture and implementation.

Changes since v3:

 - New for v4, split out from "drm: nova: Add GETPARAM parameter to read
   the GPU chipset"
---
 drivers/gpu/nova-core/gpu.rs | 57 +++++++++++++++++++-----------------
 include/uapi/drm/nova_drm.h  | 40 +++++++++++++++++++++++++
 2 files changed, 70 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 8726beb4f693..933bd3657db1 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -37,13 +37,14 @@
 mod regs;
 
 macro_rules! define_chipset {
-    ({ $($variant:ident = $value:literal),* $(,)* }) =>
+    ({ $($variant:ident),* $(,)* }) =>
     {
         ::kernel::macros::paste!(
         /// Enum representation of the GPU chipset.
         #[derive(fmt::Debug, Copy, Clone, PartialOrd, Ord, PartialEq, Eq)]
+        #[repr(u32)]
         pub(crate) enum Chipset {
-            $($variant = $value),*,
+            $($variant = uapi::[<drm_nova_chipid_NOVA_DRM_CHIPID_ $variant:upper>]),*,
         }
 
         impl Chipset {
@@ -75,7 +76,9 @@ impl TryFrom<u32> for Chipset {
             fn try_from(value: u32) -> Result<Self, Self::Error> {
                 match value {
                     $(
-                        $value => Ok(Chipset::$variant),
+                        uapi::[<drm_nova_chipid_NOVA_DRM_CHIPID_ $variant:upper>] => {
+                            Ok(Chipset::$variant)
+                        }
                     )*
                     _ => Err(ENODEV),
                 }
@@ -87,35 +90,35 @@ fn try_from(value: u32) -> Result<Self, Self::Error> {
 
 define_chipset!({
     // Turing
-    TU102 = 0x162,
-    TU104 = 0x164,
-    TU106 = 0x166,
-    TU117 = 0x167,
-    TU116 = 0x168,
+    TU102,
+    TU104,
+    TU106,
+    TU117,
+    TU116,
     // Ampere
-    GA100 = 0x170,
-    GA102 = 0x172,
-    GA103 = 0x173,
-    GA104 = 0x174,
-    GA106 = 0x176,
-    GA107 = 0x177,
+    GA100,
+    GA102,
+    GA103,
+    GA104,
+    GA106,
+    GA107,
     // Hopper
-    GH100 = 0x180,
+    GH100,
     // Ada
-    AD102 = 0x192,
-    AD103 = 0x193,
-    AD104 = 0x194,
-    AD106 = 0x196,
-    AD107 = 0x197,
+    AD102,
+    AD103,
+    AD104,
+    AD106,
+    AD107,
     // Blackwell GB10x
-    GB100 = 0x1a0,
-    GB102 = 0x1a2,
+    GB100,
+    GB102,
     // Blackwell GB20x
-    GB202 = 0x1b2,
-    GB203 = 0x1b3,
-    GB205 = 0x1b5,
-    GB206 = 0x1b6,
-    GB207 = 0x1b7,
+    GB202,
+    GB203,
+    GB205,
+    GB206,
+    GB207,
 });
 
 impl Chipset {
diff --git a/include/uapi/drm/nova_drm.h b/include/uapi/drm/nova_drm.h
index f0dcbca1908d..e35f09a1ebe8 100644
--- a/include/uapi/drm/nova_drm.h
+++ b/include/uapi/drm/nova_drm.h
@@ -37,6 +37,46 @@ enum drm_nova_architecture {
 	NOVA_DRM_ARCHITECTURE_BLACKWELL_GB20X	= 0x1b,
 };
 
+/**
+ * enum drm_nova_chipid - opaque GPU chip identifier
+ *
+ * These values identify the chip a GPU is based on. They are otherwise
+ * opaque: userspace must not assume the values carry any particular meaning
+ * or encoding, only that they may be compared against this enum.
+ */
+enum drm_nova_chipid {
+	/* Turing */
+	NOVA_DRM_CHIPID_TU102			= 0x162,
+	NOVA_DRM_CHIPID_TU104			= 0x164,
+	NOVA_DRM_CHIPID_TU106			= 0x166,
+	NOVA_DRM_CHIPID_TU117			= 0x167,
+	NOVA_DRM_CHIPID_TU116			= 0x168,
+	/* Ampere */
+	NOVA_DRM_CHIPID_GA100			= 0x170,
+	NOVA_DRM_CHIPID_GA102			= 0x172,
+	NOVA_DRM_CHIPID_GA103			= 0x173,
+	NOVA_DRM_CHIPID_GA104			= 0x174,
+	NOVA_DRM_CHIPID_GA106			= 0x176,
+	NOVA_DRM_CHIPID_GA107			= 0x177,
+	/* Hopper */
+	NOVA_DRM_CHIPID_GH100			= 0x180,
+	/* Ada */
+	NOVA_DRM_CHIPID_AD102			= 0x192,
+	NOVA_DRM_CHIPID_AD103			= 0x193,
+	NOVA_DRM_CHIPID_AD104			= 0x194,
+	NOVA_DRM_CHIPID_AD106			= 0x196,
+	NOVA_DRM_CHIPID_AD107			= 0x197,
+	/* Blackwell GB10x */
+	NOVA_DRM_CHIPID_GB100			= 0x1a0,
+	NOVA_DRM_CHIPID_GB102			= 0x1a2,
+	/* Blackwell GB20x */
+	NOVA_DRM_CHIPID_GB202			= 0x1b2,
+	NOVA_DRM_CHIPID_GB203			= 0x1b3,
+	NOVA_DRM_CHIPID_GB205			= 0x1b5,
+	NOVA_DRM_CHIPID_GB206			= 0x1b6,
+	NOVA_DRM_CHIPID_GB207			= 0x1b7,
+};
+
 /**
  * struct drm_nova_getparam - query GPU and driver metadata
  */
-- 
2.54.0