[PATCH v3 9/9] gpu: nova-core: gsp: add tests for SplitState

[Eliot Courtney]

Add tests for SplitState. They cover boundary conditions at the split
points to make sure the right number of continuation records are made.
They also check that the data concatenated is correct.

Tested-by: Zhi Wang <z...@nvidia.com>
Signed-off-by: Eliot Courtney <ecourt...@nvidia.com>
---
 drivers/gpu/nova-core/gsp/commands.rs | 114 ++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)

diff --git a/drivers/gpu/nova-core/gsp/commands.rs 
b/drivers/gpu/nova-core/gsp/commands.rs
index 6ffd0b9cbf05..74f875755e53 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -384,3 +384,117 @@ fn init_variable_payload(
         }
     }
 }
+
+#[kunit_tests(nova_core_gsp_commands)]
+mod tests {
+    use super::*;
+
+    struct TestPayload {
+        data: KVVec<u8>,
+    }
+
+    impl TestPayload {
+        fn generate_pattern(len: usize) -> Result<KVVec<u8>> {
+            let mut data = KVVec::with_capacity(len, GFP_KERNEL)?;
+            for i in 0..len {
+                data.push(i as u8, GFP_KERNEL)?;
+            }
+            Ok(data)
+        }
+
+        fn new(len: usize) -> Result<Self> {
+            Ok(Self {
+                data: Self::generate_pattern(len)?,
+            })
+        }
+    }
+
+    impl CommandToGsp for TestPayload {
+        const FUNCTION: MsgFunction = MsgFunction::Nop;
+        type Command = ();
+        type InitError = Infallible;
+
+        fn init(&self) -> impl Init<Self::Command, Self::InitError> {
+            <()>::init_zeroed()
+        }
+
+        fn variable_payload_len(&self) -> usize {
+            self.data.len()
+        }
+
+        fn init_variable_payload(
+            &self,
+            dst: &mut SBufferIter<core::array::IntoIter<&mut [u8], 2>>,
+        ) -> Result {
+            dst.write_all(self.data.as_slice())
+        }
+    }
+
+    const MAX_CMD_SIZE: usize = SplitState::<TestPayload>::MAX_CMD_SIZE;
+
+    fn read_payload(cmd: &impl CommandToGsp) -> Result<KVVec<u8>> {
+        let len = cmd.variable_payload_len();
+        let mut buf = KVVec::from_elem(0u8, len, GFP_KERNEL)?;
+        let mut sbuf = SBufferIter::new_writer([buf.as_mut_slice(), &mut []]);
+        cmd.init_variable_payload(&mut sbuf)?;
+        drop(sbuf);
+        Ok(buf)
+    }
+
+    struct SplitTest {
+        payload_size: usize,
+        num_continuations: usize,
+    }
+
+    fn check_split(t: SplitTest) -> Result {
+        let payload = TestPayload::new(t.payload_size)?;
+        let mut state = SplitState::new(&payload)?;
+
+        let mut buf = read_payload(&state.command(payload))?;
+        assert!(buf.len() <= MAX_CMD_SIZE);
+
+        let mut num_continuations = 0;
+        while let Some(cont) = state.next_continuation_record() {
+            let payload = read_payload(&cont)?;
+            assert!(payload.len() <= MAX_CMD_SIZE);
+            buf.extend_from_slice(&payload, GFP_KERNEL)?;
+            num_continuations += 1;
+        }
+
+        assert_eq!(num_continuations, t.num_continuations);
+        assert_eq!(
+            buf.as_slice(),
+            TestPayload::generate_pattern(t.payload_size)?.as_slice()
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn split_command() -> Result {
+        check_split(SplitTest {
+            payload_size: 0,
+            num_continuations: 0,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_CMD_SIZE,
+            num_continuations: 0,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_CMD_SIZE + 1,
+            num_continuations: 1,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_CMD_SIZE * 2,
+            num_continuations: 1,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_CMD_SIZE * 2 + 1,
+            num_continuations: 2,
+        })?;
+        check_split(SplitTest {
+            payload_size: MAX_CMD_SIZE * 3 + MAX_CMD_SIZE / 2,
+            num_continuations: 3,
+        })?;
+        Ok(())
+    }
+}

-- 
2.53.0