Re: [PATCH v3 11/14] gpu: nova-core: sequencer: Implement core resume operation

[Lyude Paul]

Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>

On Thu, 2025-11-06 at 18:11 -0500, Joel Fernandes wrote:
> 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@xxxxxxxxxx>
> ---
>  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 0192ac61df4c..3b4796425d0b 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,
> @@ -227,6 +231,47 @@ 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(())
> +            }
>          }
>      }
>  }

-- 
Cheers,
 Lyude Paul (she/her)
 Senior Software Engineer at Red Hat

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