gpu: nova-core: Implement the GSP sequencer

Implement the GSP sequencer which culminates in INIT_DONE message being
received from the GSP indicating that the GSP has successfully booted.

This is just initial sequencer support, the actual commands will be
added in the next patches.

Signed-off-by: Joel Fernandes <[e-mail]>
[[e-mail]: move GspSequencerInfo definition before its impl
blocks and rename it to GspSequence, adapt imports in sequencer.rs to
new formatting rules, remove `timeout` argument to harmonize with other
commands.]
Signed-off-by: Alexandre Courbot <[e-mail]>
Message-ID: <[e-mail]>

drivers/gpu/nova-core/gsp.rs

···
 pub(crate) mod cmdq;
 pub(crate) mod commands;
 mod fw;
+mod sequencer;
 
 pub(crate) use fw::{
     GspFwWprMeta,

drivers/gpu/nova-core/gsp/boot.rs

···
     gpu::Chipset,
     gsp::{
         commands,
+        sequencer::{
+            GspSequencer,
+            GspSequencerParams, //
+        },
         GspFwWprMeta, //
     },
     regs,
···
             "RISC-V active? {}\n",
             gsp_falcon.is_riscv_active(bar),
         );
+
+        // Create and run the GSP sequencer.
+        let seq_params = GspSequencerParams {
+            bootloader_app_version: gsp_fw.bootloader.app_version,
+            libos_dma_handle: libos_handle,
+            gsp_falcon,
+            sec2_falcon,
+            dev: pdev.as_ref().into(),
+            bar,
+        };
+        GspSequencer::run(&mut self.cmdq, seq_params)?;
 
         Ok(())
     }

drivers/gpu/nova-core/gsp/cmdq.rs

···
     /// - `EIO` if there was some inconsistency (e.g. message shorter than advertised) on the
     ///   message queue.
     /// - `EINVAL` if the function of the message was unrecognized.
-    #[expect(unused)]
     pub(crate) fn receive_msg<M: MessageFromGsp>(&mut self, timeout: Delta) -> Result<M>
     where
         // This allows all error types, including `Infallible`, to be used for `M::InitError`.

drivers/gpu/nova-core/gsp/fw.rs

···
 #[repr(transparent)]
 pub(crate) struct RunCpuSequencer(r570_144::rpc_run_cpu_sequencer_v17_00);
 
-#[expect(unused)]
 impl RunCpuSequencer {
     /// Returns the command index.
     pub(crate) fn cmd_index(&self) -> u32 {

drivers/gpu/nova-core/gsp/sequencer.rs

···
+// SPDX-License-Identifier: GPL-2.0
+
+//! GSP Sequencer implementation for Pre-hopper GSP boot sequence.
+
+use core::{
+    array,
+    mem::size_of, //
+};
+
+use kernel::{
+    device,
+    prelude::*,
+    time::Delta,
+    transmute::FromBytes,
+    types::ARef, //
+};
+
+use crate::{
+    driver::Bar0,
+    falcon::{
+        gsp::Gsp,
+        sec2::Sec2,
+        Falcon, //
+    },
+    gsp::{
+        cmdq::{
+            Cmdq,
+            MessageFromGsp, //
+        },
+        fw,
+    },
+    sbuffer::SBufferIter,
+};
+
+/// GSP Sequencer information containing the command sequence and data.
+struct GspSequence {
+    /// Current command index for error reporting.
+    cmd_index: u32,
+    /// Command data buffer containing the sequence of commands.
+    cmd_data: KVec<u8>,
+}
+
+impl MessageFromGsp for GspSequence {
+    const FUNCTION: fw::MsgFunction = fw::MsgFunction::GspRunCpuSequencer;
+    type InitError = Error;
+    type Message = fw::RunCpuSequencer;
+
+    fn read(
+        msg: &Self::Message,
+        sbuffer: &mut SBufferIter<array::IntoIter<&[u8], 2>>,
+    ) -> Result<Self, Self::InitError> {
+        let cmd_data = sbuffer.flush_into_kvec(GFP_KERNEL)?;
+        Ok(GspSequence {
+            cmd_index: msg.cmd_index(),
+            cmd_data,
+        })
+    }
+}
+
+const CMD_SIZE: usize = size_of::<fw::SequencerBufferCmd>();
+
+/// GSP Sequencer Command types with payload data.
+/// Commands have an opcode and an opcode-dependent struct.
+#[allow(dead_code)]
+pub(crate) enum GspSeqCmd {}
+
+impl GspSeqCmd {
+    /// Creates a new `GspSeqCmd` from raw data returning the command and its size in bytes.
+    pub(crate) fn new(data: &[u8], _dev: &device::Device) -> Result<(Self, usize)> {
+        let _fw_cmd = fw::SequencerBufferCmd::from_bytes(data).ok_or(EINVAL)?;
+        let _opcode_size = core::mem::size_of::<u32>();
+
+        // NOTE: At this commit, NO opcodes exist yet, so just return error.
+        // Later commits will add match arms here.
+        Err(EINVAL)
+    }
+}
+
+/// GSP Sequencer for executing firmware commands during boot.
+#[expect(dead_code)]
+pub(crate) struct GspSequencer<'a> {
+    /// Sequencer information with command data.
+    seq_info: GspSequence,
+    /// `Bar0` for register access.
+    bar: &'a Bar0,
+    /// SEC2 falcon for core operations.
+    sec2_falcon: &'a Falcon<Sec2>,
+    /// GSP falcon for core operations.
+    gsp_falcon: &'a Falcon<Gsp>,
+    /// LibOS DMA handle address.
+    libos_dma_handle: u64,
+    /// Bootloader application version.
+    bootloader_app_version: u32,
+    /// Device for logging.
+    dev: ARef<device::Device>,
+}
+
+/// Trait for running sequencer commands.
+pub(crate) trait GspSeqCmdRunner {
+    fn run(&self, sequencer: &GspSequencer<'_>) -> Result;
+}
+
+impl GspSeqCmdRunner for GspSeqCmd {
+    fn run(&self, _seq: &GspSequencer<'_>) -> Result {
+        Ok(())
+    }
+}
+
+/// Iterator over GSP sequencer commands.
+pub(crate) struct GspSeqIter<'a> {
+    /// Command data buffer.
+    cmd_data: &'a [u8],
+    /// Current position in the buffer.
+    current_offset: usize,
+    /// Total number of commands to process.
+    total_cmds: u32,
+    /// Number of commands processed so far.
+    cmds_processed: u32,
+    /// Device for logging.
+    dev: ARef<device::Device>,
+}
+
+impl<'a> Iterator for GspSeqIter<'a> {
+    type Item = Result<GspSeqCmd>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        // Stop if we've processed all commands or reached the end of data.
+        if self.cmds_processed >= self.total_cmds || self.current_offset >= self.cmd_data.len() {
+            return None;
+        }
+
+        // Check if we have enough data for opcode.
+        if self.current_offset + core::mem::size_of::<u32>() > self.cmd_data.len() {
+            return Some(Err(EIO));
+        }
+
+        let offset = self.current_offset;
+
+        // Handle command creation based on available data,
+        // zero-pad if necessary (since last command may not be full size).
+        let mut buffer = [0u8; CMD_SIZE];
+        let copy_len = if offset + CMD_SIZE <= self.cmd_data.len() {
+            CMD_SIZE
+        } else {
+            self.cmd_data.len() - offset
+        };
+        buffer[..copy_len].copy_from_slice(&self.cmd_data[offset..offset + copy_len]);
+        let cmd_result = GspSeqCmd::new(&buffer, &self.dev);
+
+        cmd_result.map_or_else(
+            |_err| {
+                dev_err!(self.dev, "Error parsing command at offset {}", offset);
+                None
+            },
+            |(cmd, size)| {
+                self.current_offset += size;
+                self.cmds_processed += 1;
+                Some(Ok(cmd))
+            },
+        )
+    }
+}
+
+impl<'a> GspSequencer<'a> {
+    fn iter(&self) -> GspSeqIter<'_> {
+        let cmd_data = &self.seq_info.cmd_data[..];
+
+        GspSeqIter {
+            cmd_data,
+            current_offset: 0,
+            total_cmds: self.seq_info.cmd_index,
+            cmds_processed: 0,
+            dev: self.dev.clone(),
+        }
+    }
+}
+
+/// Parameters for running the GSP sequencer.
+pub(crate) struct GspSequencerParams<'a> {
+    /// Bootloader application version.
+    pub(crate) bootloader_app_version: u32,
+    /// LibOS DMA handle address.
+    pub(crate) libos_dma_handle: u64,
+    /// GSP falcon for core operations.
+    pub(crate) gsp_falcon: &'a Falcon<Gsp>,
+    /// SEC2 falcon for core operations.
+    pub(crate) sec2_falcon: &'a Falcon<Sec2>,
+    /// Device for logging.
+    pub(crate) dev: ARef<device::Device>,
+    /// BAR0 for register access.
+    pub(crate) bar: &'a Bar0,
+}
+
+impl<'a> GspSequencer<'a> {
+    pub(crate) fn run(cmdq: &mut Cmdq, params: GspSequencerParams<'a>) -> Result {
+        let seq_info = loop {
+            match cmdq.receive_msg::<GspSequence>(Delta::from_secs(10)) {
+                Ok(seq_info) => break seq_info,
+                Err(ERANGE) => continue,
+                Err(e) => return Err(e),
+            }
+        };
+
+        let sequencer = GspSequencer {
+            seq_info,
+            bar: params.bar,
+            sec2_falcon: params.sec2_falcon,
+            gsp_falcon: params.gsp_falcon,
+            libos_dma_handle: params.libos_dma_handle,
+            bootloader_app_version: params.bootloader_app_version,
+            dev: params.dev,
+        };
+
+        dev_dbg!(sequencer.dev, "Running CPU Sequencer commands");
+
+        for cmd_result in sequencer.iter() {
+            match cmd_result {
+                Ok(cmd) => cmd.run(&sequencer)?,
+                Err(e) => {
+                    dev_err!(
+                        sequencer.dev,
+                        "Error running command at index {}",
+                        sequencer.seq_info.cmd_index
+                    );
+                    return Err(e);
+                }
+            }
+        }
+
+        dev_dbg!(
+            sequencer.dev,
+            "CPU Sequencer commands completed successfully"
+        );
+        Ok(())
+    }
+}

drivers/gpu/nova-core/sbuffer.rs

···
     /// Read all the remaining data into a [`KVec`].
     ///
     /// `self` will be empty after this operation.
-    #[expect(unused)]
     pub(crate) fn flush_into_kvec(&mut self, flags: kernel::alloc::Flags) -> Result<KVec<u8>> {
         let mut buf = KVec::<u8>::new();