nak: Implement shader clock

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24998>

src/nouveau/compiler/nak_encode_sm75.rs

@@ -1480,6 +1480,12 @@ impl SM75Instr {
         self.set_pred_src(87..90, 90, SrcRef::True.into());
     }
 
+    fn encode_cs2r(&mut self, op: &OpCS2R) {
+        self.set_opcode(0x805);
+        self.set_dst(op.dst);
+        self.set_field(72..80, op.idx);
+    }
+
     fn encode_s2r(&mut self, op: &OpS2R) {
         self.set_opcode(0x919);
         self.set_dst(op.dst);
@@ -1591,6 +1597,7 @@ impl SM75Instr {
             Op::Bra(op) => si.encode_bra(&op, ip, block_offsets),
             Op::Exit(op) => si.encode_exit(&op),
             Op::Bar(op) => si.encode_bar(&op),
+            Op::CS2R(op) => si.encode_cs2r(&op),
             Op::S2R(op) => si.encode_s2r(&op),
             Op::PopC(op) => si.encode_popc(&op),
             Op::Brev(op) => si.encode_brev(&op),

src/nouveau/compiler/nak_from_nir.rs

@@ -1285,12 +1285,21 @@ impl<'a> ShaderFromNir<'a> {
             }
             nir_intrinsic_load_sysval_nv => {
                 let idx = u8::try_from(intrin.base()).unwrap();
-                let dst = b.alloc_ssa(RegFile::GPR, 1);
+                debug_assert!(intrin.def.num_components == 1);
-
+                let dst = b.alloc_ssa(RegFile::GPR, intrin.def.bit_size() / 32);
-                b.push_op(OpS2R {
+                if intrin.def.bit_size() == 32 {
-                    dst: dst.into(),
+                    b.push_op(OpS2R {
-                    idx: idx,
+                        dst: dst.into(),
-                });
+                        idx: idx,
+                    });
+                } else if intrin.def.bit_size() == 64 {
+                    b.push_op(OpCS2R {
+                        dst: dst.into(),
+                        idx: idx,
+                    });
+                } else {
+                    panic!("Unknown sysval_nv bit size");
+                }
                 self.set_dst(&intrin.def, dst);
             }
             nir_intrinsic_load_ubo => {

src/nouveau/compiler/nak_ir.rs

@@ -3040,6 +3040,19 @@ impl fmt::Display for OpBar {
     }
 }
 
+#[repr(C)]
+#[derive(SrcsAsSlice, DstsAsSlice)]
+pub struct OpCS2R {
+    pub dst: Dst,
+    pub idx: u8,
+}
+
+impl fmt::Display for OpCS2R {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "CS2R {} sr[{:#x}]", self.dst, self.idx)
+    }
+}
+
 #[repr(C)]
 #[derive(SrcsAsSlice, DstsAsSlice)]
 pub struct OpS2R {
@@ -3586,6 +3599,7 @@ pub enum Op {
     Bra(OpBra),
     Exit(OpExit),
     Bar(OpBar),
+    CS2R(OpCS2R),
     S2R(OpS2R),
     Undef(OpUndef),
     PhiSrcs(OpPhiSrcs),
@@ -3938,6 +3952,7 @@ impl Instr {
                 Some(15)
             }
             Op::Sel(_) => Some(15),
+            Op::CS2R(_) => None,
             Op::S2R(_) => None,
             Op::ALd(_) => None,
             Op::ASt(_) => Some(15),

src/nouveau/compiler/nak_nir.c

@@ -482,6 +482,11 @@ nak_nir_lower_system_value_instr(nir_builder *b, nir_instr *instr, void *data)
       break;
    }
 
+   case nir_intrinsic_shader_clock:
+      val = nir_load_sysval_nv(b, 64, .base = 0x50);
+      val = nir_unpack_64_2x32(b, val);
+      break;
+
    default:
       return false;
    }