[PATCH v2 5/5] gpu: nova-core: gsp: cmdq: expose the sequence number of sent commands

[Alexandre Courbot <acourbot@nvidia.com>]

The r000 firmware requires matching the sequence number of sent commands
with the responses received from the GSP. Make `send_command_element`
return the sequence number to that end, and ignore it for now.

No functional change intended.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpu/nova-core/gsp/cmdq.rs     | 11 +++++++----
 drivers/gpu/nova-core/gsp/cmdq/rpc.rs |  4 +++-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/nova-core/gsp/cmdq.rs b/drivers/gpu/nova-core/gsp/cmdq.rs
index 33cb9174c1e6..65f25d3c4d98 100644
--- a/drivers/gpu/nova-core/gsp/cmdq.rs
+++ b/drivers/gpu/nova-core/gsp/cmdq.rs
@@ -524,27 +524,30 @@ impl CmdqInner<'_> {
     /// Allocate enough space on the command queue to store `command`, initialize it with
     /// [`CommandElement::write`], and send the command to the GSP.
     ///
+    /// Returns the sequence number of the sent element.
+    ///
     /// # Errors
     ///
     /// - `EMSGSIZE` if the command exceeds the maximum queue element size.
     /// - `ETIMEDOUT` if space does not become available within the timeout.
     ///
     /// Error codes returned by [`CommandElement::write`] are returned as-is.
-    fn send_command_element<E: CommandElement>(&mut self, command: E) -> Result {
+    fn send_command_element<E: CommandElement>(&mut self, command: E) -> Result<u32> {
         let size_in_bytes = command.size();
+        let seq = self.seq;
         let mut dst = self
             .gsp_mem
             .allocate_command(size_in_bytes, Self::ALLOCATE_TIMEOUT)?;
 
         // Fill the header.
-        let msg_element_init = GspMsgElement::init(self.seq, size_in_bytes);
+        let msg_element_init = GspMsgElement::init(seq, size_in_bytes);
         // SAFETY: `dst.header` is a valid reference, and is not touched if the initializer fails.
         unsafe {
             pin_init::raw_try_init(core::ptr::from_mut(dst.header), msg_element_init)?;
         }
 
         // Write the message payload.
-        command.write(self.dev, self.seq, &mut dst)?;
+        command.write(self.dev, seq, &mut dst)?;
 
         // Compute checksum now that the whole message is ready.
         dst.header
@@ -559,7 +562,7 @@ fn send_command_element<E: CommandElement>(&mut self, command: E) -> Result {
         self.seq += 1;
         self.gsp_mem.advance_cpu_write_ptr(elem_count);
 
-        Ok(())
+        Ok(seq)
     }
 
     /// Wait for a message to become available on the message queue.
diff --git a/drivers/gpu/nova-core/gsp/cmdq/rpc.rs b/drivers/gpu/nova-core/gsp/cmdq/rpc.rs
index 2c52ec78871b..36cba7c28d3e 100644
--- a/drivers/gpu/nova-core/gsp/cmdq/rpc.rs
+++ b/drivers/gpu/nova-core/gsp/cmdq/rpc.rs
@@ -354,7 +354,9 @@ fn send_rpc_command<M>(&mut self, command: M) -> Result
         Error: From<M::InitError>,
     {
         match SplitState::new(command)? {
-            SplitState::Single(command) => self.send_command_element(RpcCommandElement(command)),
+            SplitState::Single(command) => self
+                .send_command_element(RpcCommandElement(command))
+                .map(|_| ()),
             SplitState::Split(command, mut continuations) => {
                 self.send_command_element(RpcCommandElement(command))?;
 

-- 
2.56.0