[PATCH v2 11/12] nova-core: sequencer: Implement core resume operation

[Joel Fernandes <joelagnelf@nvidia.com>]

Implement core resume operation. This is the last step of the sequencer
resulting in resume of the GSP and proceeding to INIT_DONE stage of GSP
boot.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
 drivers/gpu/nova-core/falcon/gsp.rs    |  1 -
 drivers/gpu/nova-core/gsp/fw.rs        |  1 -
 drivers/gpu/nova-core/gsp/sequencer.rs | 49 ++++++++++++++++++++++++--
 3 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/nova-core/falcon/gsp.rs b/drivers/gpu/nova-core/falcon/gsp.rs
index e0c0b18ec5bf..391699dc3a8c 100644
--- a/drivers/gpu/nova-core/falcon/gsp.rs
+++ b/drivers/gpu/nova-core/falcon/gsp.rs
@@ -37,7 +37,6 @@ pub(crate) fn clear_swgen0_intr(&self, bar: &Bar0) {
     }
 
     /// Checks if GSP reload/resume has completed during the boot process.
-    #[expect(dead_code)]
     pub(crate) fn check_reload_completed(&self, bar: &Bar0, timeout: Delta) -> Result<bool> {
         read_poll_timeout(
             || Ok(regs::NV_PGC6_BSI_SECURE_SCRATCH_14::read(bar)),
diff --git a/drivers/gpu/nova-core/gsp/fw.rs b/drivers/gpu/nova-core/gsp/fw.rs
index 53e28458cd7d..bb79f92432aa 100644
--- a/drivers/gpu/nova-core/gsp/fw.rs
+++ b/drivers/gpu/nova-core/gsp/fw.rs
@@ -543,7 +543,6 @@ pub(crate) fn element_count(&self) -> u32 {
     }
 }
 
-#[expect(unused)]
 pub(crate) use r570_144::{
     // GSP sequencer run structure with information on how to run the sequencer.
     rpc_run_cpu_sequencer_v17_00,
diff --git a/drivers/gpu/nova-core/gsp/sequencer.rs b/drivers/gpu/nova-core/gsp/sequencer.rs
index 127b293a161c..ecc80f668dc8 100644
--- a/drivers/gpu/nova-core/gsp/sequencer.rs
+++ b/drivers/gpu/nova-core/gsp/sequencer.rs
@@ -52,6 +52,7 @@ pub(crate) enum GspSeqCmd {
     CoreReset,
     CoreStart,
     CoreWaitForHalt,
+    CoreResume,
 }
 
 impl GspSeqCmd {
@@ -83,6 +84,7 @@ pub(crate) fn from_fw_cmd(cmd: &fw::GSP_SEQUENCER_BUFFER_CMD) -> Result<Self> {
             fw::GSP_SEQ_BUF_OPCODE_GSP_SEQ_BUF_OPCODE_CORE_WAIT_FOR_HALT => {
                 Ok(GspSeqCmd::CoreWaitForHalt)
             }
+            fw::GSP_SEQ_BUF_OPCODE_GSP_SEQ_BUF_OPCODE_CORE_RESUME => Ok(GspSeqCmd::CoreResume),
             _ => Err(EINVAL),
         }
     }
@@ -105,7 +107,10 @@ pub(crate) fn size_bytes(&self) -> usize {
         let opcode_size = size_of::<fw::GSP_SEQ_BUF_OPCODE>();
         match self {
             // Each simple command type just adds 4 bytes (opcode_size) for the header.
-            GspSeqCmd::CoreReset | GspSeqCmd::CoreStart | GspSeqCmd::CoreWaitForHalt => opcode_size,
+            GspSeqCmd::CoreReset
+            | GspSeqCmd::CoreStart
+            | GspSeqCmd::CoreWaitForHalt
+            | GspSeqCmd::CoreResume => opcode_size,
 
             // For commands with payloads, add the payload size in bytes.
             GspSeqCmd::RegWrite(_) => opcode_size + size_of::<fw::GSP_SEQ_BUF_PAYLOAD_REG_WRITE>(),
@@ -119,7 +124,6 @@ pub(crate) fn size_bytes(&self) -> usize {
     }
 }
 
-#[expect(dead_code)]
 pub(crate) struct GspSequencer<'a> {
     seq_info: GspSequencerInfo<'a>,
     bar: &'a Bar0,
@@ -259,6 +263,47 @@ fn run(&self, seq: &GspSequencer<'_>) -> Result {
                 seq.gsp_falcon.wait_till_halted(seq.bar)?;
                 Ok(())
             }
+            GspSeqCmd::CoreResume => {
+                dev_dbg!(seq.dev, "CoreResume\n");
+                // At this point, 'SEC2-RTOS' has been loaded into SEC2 by the sequencer
+                // but neither SEC2-RTOS nor GSP-RM is running yet. This part of the
+                // sequencer will start both.
+
+                // Reset the GSP to prepare it for resuming.
+                seq.gsp_falcon.reset(seq.bar)?;
+
+                // Write the libOS DMA handle to GSP mailboxes.
+                seq.gsp_falcon.write_mailboxes(
+                    seq.bar,
+                    Some(seq.libos_dma_handle as u32),
+                    Some((seq.libos_dma_handle >> 32) as u32),
+                )?;
+
+                // Start the SEC2 falcon which will trigger GSP-RM to resume on the GSP.
+                seq.sec2_falcon.start(seq.bar)?;
+
+                // Poll until GSP-RM reload/resume has completed (up to 2 seconds).
+                seq.gsp_falcon
+                    .check_reload_completed(seq.bar, Delta::from_secs(2))?;
+
+                // Verify SEC2 completed successfully by checking its mailbox for errors.
+                let mbox0 = seq.sec2_falcon.read_mailbox0(seq.bar)?;
+                if mbox0 != 0 {
+                    dev_err!(seq.dev, "Sequencer: sec2 errors: {:?}\n", mbox0);
+                    return Err(EIO);
+                }
+
+                // Configure GSP with the bootloader version.
+                seq.gsp_falcon
+                    .write_os_version(seq.bar, seq.gsp_fw.bootloader.app_version);
+
+                // Verify the GSP's RISC-V core is active indicating successful GSP boot.
+                if !seq.gsp_falcon.is_riscv_active(seq.bar) {
+                    dev_err!(seq.dev, "Sequencer: RISC-V core is not active\n");
+                    return Err(EIO);
+                }
+                Ok(())
+            }
         }
     }
 }
-- 
2.34.1