gpu: nova-core: gsp: Add support for checking if GSP reloaded

During the sequencer process, we need to check if GSP was successfully
reloaded. Add functionality to check for the same.

Reviewed-by: Lyude Paul <[e-mail]>
Signed-off-by: Joel Fernandes <[e-mail]>
Signed-off-by: Alexandre Courbot <[e-mail]>
Message-ID: <[e-mail]>

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

···
 // SPDX-License-Identifier: GPL-2.0
 
+use kernel::{
+    io::poll::read_poll_timeout,
+    prelude::*,
+    time::Delta, //
+};
+
 use crate::{
     driver::Bar0,
     falcon::{
···
         regs::NV_PFALCON_FALCON_IRQSCLR::default()
             .set_swgen0(true)
             .write(bar, &Gsp::ID);
+    }
+
+    /// 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)),
+            |val| val.boot_stage_3_handoff(),
+            Delta::ZERO,
+            timeout,
+        )
+        .map(|_| true)
     }
 }

drivers/gpu/nova-core/regs.rs

···
 // These scratch registers remain powered on even in a low-power state and have a designated group
 // number.
 
+// Boot Sequence Interface (BSI) register used to determine
+// if GSP reload/resume has completed during the boot process.
+register!(NV_PGC6_BSI_SECURE_SCRATCH_14 @ 0x001180f8 {
+    26:26   boot_stage_3_handoff as bool;
+});
+
 // Privilege level mask register. It dictates whether the host CPU has privilege to access the
 // `PGC6_AON_SECURE_SCRATCH_GROUP_05` register (which it needs to read GFW_BOOT).
 register!(NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_PRIV_LEVEL_MASK @ 0x00118128,