[PATCH v3 09/12] gpu: nova-core: introduce GspBootMethod

The GSP boot method is currently determined by two ad-hoc methods of
`Chipset`: `uses_fsp` (a boolean telling whether to use the FSP boot
path or the Sec2 Booter one) and `needs_fwsec_bootloader` (another
boolean valid only for the Sec2 Booter method that tells whether the
FWSEC bootloader must be used).

This is neither extensible nor sound: the combination `uses_fsp &&
needs_fwsec_bootloader` is invalid, but can still be expressed.

Thus, unify these two predicates into a single `gsp_boot_method` method
that returns an enum type unambiguously describing the boot method to
use. This ensures that no invalid combination can be expressed, which
makes matching sounder.

Signed-off-by: Alexandre Courbot <[email protected]>
---
 drivers/gpu/nova-core/firmware.rs       | 25 ++++++++++++--------
 drivers/gpu/nova-core/firmware/fwsec.rs |  5 ++--
 drivers/gpu/nova-core/gpu.rs            | 16 -------------
 drivers/gpu/nova-core/gsp.rs            | 42 ++++++++++++++++++++++++++++++++-
 drivers/gpu/nova-core/gsp/hal.rs        | 22 ++++++++---------
 5 files changed, 70 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/nova-core/firmware.rs b/drivers/gpu/nova-core/firmware.rs
index 80e948bf7511..7a5978f93f4e 100644
--- a/drivers/gpu/nova-core/firmware.rs
+++ b/drivers/gpu/nova-core/firmware.rs
@@ -21,6 +21,7 @@
         FalconFirmware, //
     },
     gpu,
+    gsp::GspBootMethod,
     num::{
         FromSafeCast,
         IntoSafeCast, //
@@ -429,17 +430,21 @@ const fn make_entry_chipset(self, chipset: gpu::Chipset) -> Self {
 
         // FSP-based chipsets (Hopper, Blackwell and later) boot the GSP via the FMC image loaded by
         // FSP. Older chipsets use the SEC2 booter instead.
-        let this = if chipset.uses_fsp() {
-            this.make_entry_file(name, "fmc")
-        } else {
-            this.make_entry_file(name, "booter_load")
-                .make_entry_file(name, "booter_unload")
-        };
+        match chipset.gsp_boot_method() {
+            GspBootMethod::Sec2 {
+                needs_fwsec_bootloader,
+            } => {
+                let mut this = this
+                    .make_entry_file(name, "booter_load")
+                    .make_entry_file(name, "booter_unload");
 
-        if chipset.needs_fwsec_bootloader() {
-            this.make_entry_file(name, "gen_bootloader")
-        } else {
-            this
+                if needs_fwsec_bootloader {
+                    this = this.make_entry_file(name, "gen_bootloader")
+                }
+
+                this
+            }
+            GspBootMethod::Fsp => this.make_entry_file(name, "fmc"),
         }
     }
 
diff --git a/drivers/gpu/nova-core/firmware/fwsec.rs b/drivers/gpu/nova-core/firmware/fwsec.rs
index 199ae2adb664..a3a43a27ddd7 100644
--- a/drivers/gpu/nova-core/firmware/fwsec.rs
+++ b/drivers/gpu/nova-core/firmware/fwsec.rs
@@ -388,8 +388,9 @@ pub(crate) fn new(
     /// Loads the FWSEC firmware into `falcon` and execute it.
     ///
     /// This must only be called on chipsets that do not need the FWSEC bootloader (i.e., where
-    /// [`Chipset::needs_fwsec_bootloader()`](crate::gpu::Chipset::needs_fwsec_bootloader) returns
-    /// `false`). On chipsets that do, use [`bootloader::FwsecFirmwareWithBl`] instead.
+    /// [`Chipset::gsp_boot_method()`](crate::gpu::Chipset::gsp_boot_method) returns
+    /// `GspBootMethod::Sec2 { needs_fwsec_bootloader: false }`). On chipsets where
+    /// `needs_fwsec_bootloader` is `true`, use [`bootloader::FwsecFirmwareWithBl`] instead.
     pub(crate) fn run(
         &self,
         dev: &Device<device::Bound>,
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 4ee0a43ac4b6..b3f04239d938 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -133,22 +133,6 @@ pub(crate) const fn arch(self) -> Architecture {
         }
     }
 
-    /// Returns `true` if this chipset requires the PIO-loaded bootloader in order to boot FWSEC.
-    ///
-    /// This includes all chipsets < GA102.
-    pub(crate) const fn needs_fwsec_bootloader(self) -> bool {
-        matches!(self.arch(), Architecture::Turing) || matches!(self, Self::GA100)
-    }
-
-    /// Returns `true` if this chipset boots via FSP (Hopper and later), which requires the FMC
-    /// firmware image.
-    pub(crate) const fn uses_fsp(self) -> bool {
-        matches!(
-            self.arch(),
-            Architecture::Hopper | Architecture::BlackwellGB10x | Architecture::BlackwellGB20x
-        )
-    }
-
     /// Returns the address range of the PCI config mirror space.
     pub(crate) fn pci_config_mirror_range(self) -> Range<u32> {
         hal::gpu_hal(self).pci_config_mirror_range()
diff --git a/drivers/gpu/nova-core/gsp.rs b/drivers/gpu/nova-core/gsp.rs
index 73e93403601c..771b38e6335d 100644
--- a/drivers/gpu/nova-core/gsp.rs
+++ b/drivers/gpu/nova-core/gsp.rs
@@ -38,7 +38,10 @@
         sec2::Sec2 as Sec2Falcon,
         Falcon, //
     },
-    gpu::Chipset,
+    gpu::{
+        Architecture,
+        Chipset, //
+    },
     gsp::{
         cmdq::Cmdq,
         fw::{
@@ -217,5 +220,42 @@ pub(crate) fn get_static_info(&self, bar: Bar0<'_>) -> Result<commands::GetGspSt
     }
 }
 
+/// Method used to boot the GSP.
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub(crate) enum GspBootMethod {
+    /// GSP is booted by running FWSEC-FRTS on the GSP falcon, followed by the Booter loader on the
+    /// SEC2 falcon.
+    ///
+    /// `needs_fwsec_bootloader` indicates whether the chipset requires the PIO-loaded bootloader in
+    /// order to boot FWSEC.
+    Sec2 { needs_fwsec_bootloader: bool },
+    /// GSP is booted via FSP Chain-of-Trust.
+    Fsp,
+}
+
+impl Chipset {
+    /// Returns the method used to boot the GSP on this chipset.
+    pub(crate) const fn gsp_boot_method(self) -> GspBootMethod {
+        match self.arch() {
+            // All Turing chipsets require the FWSEC bootloader.
+            Architecture::Turing => GspBootMethod::Sec2 {
+                needs_fwsec_bootloader: true,
+            },
+            // GA100 also requires the FWSEC bootloader.
+            Architecture::Ampere if matches!(self, Self::GA100) => GspBootMethod::Sec2 {
+                needs_fwsec_bootloader: true,
+            },
+            // Other Ampere chipsets, as well as Ada chipsets, do not require the FWSEC bootloader.
+            Architecture::Ampere | Architecture::Ada => GspBootMethod::Sec2 {
+                needs_fwsec_bootloader: false,
+            },
+            // Hopper and more recent use the FSP Chain-of-Trust boot method.
+            Architecture::Hopper | Architecture::BlackwellGB10x | Architecture::BlackwellGB20x => {
+                GspBootMethod::Fsp
+            }
+        }
+    }
+}
+
 /// Opaque bundle required to unload the GSP. Created by [`Gsp::boot`], consumed by [`Gsp::unload`].
 pub(crate) struct UnloadBundle(KBox<dyn hal::UnloadBundle>);
diff --git a/drivers/gpu/nova-core/gsp/hal.rs b/drivers/gpu/nova-core/gsp/hal.rs
index eddb4e8bf510..90f076f640e0 100644
--- a/drivers/gpu/nova-core/gsp/hal.rs
+++ b/drivers/gpu/nova-core/gsp/hal.rs
@@ -13,13 +13,11 @@
 use crate::{
     fb::FbLayout,
     firmware::gsp::GspFirmware,
-    gpu::{
-        Architecture,
-        Chipset, //
-    },
+    gpu::Chipset,
     gsp::{
         Gsp,
         GspBootContext,
+        GspBootMethod,
         GspFwWprMeta, //
     },
 };
@@ -59,12 +57,14 @@ fn post_boot(&self, _gsp: &Gsp, _ctx: &GspBootContext<'_>, _gsp_fw: &GspFirmware
 
 /// Returns the GSP HAL to be used for `chipset`.
 pub(super) fn gsp_hal(chipset: Chipset) -> &'static dyn GspHal {
-    match chipset.arch() {
-        Architecture::Turing => tu102::TU102_HAL,
-        Architecture::Ampere if matches!(chipset, Chipset::GA100) => tu102::TU102_HAL,
-        Architecture::Ampere | Architecture::Ada => ga102::GA102_HAL,
-        Architecture::Hopper | Architecture::BlackwellGB10x | Architecture::BlackwellGB20x => {
-            gh100::GH100_HAL
-        }
+    // The GSP HAL is entirely determined by the boot method.
+    match chipset.gsp_boot_method() {
+        GspBootMethod::Sec2 {
+            needs_fwsec_bootloader: true,
+        } => tu102::TU102_HAL,
+        GspBootMethod::Sec2 {
+            needs_fwsec_bootloader: false,
+        } => ga102::GA102_HAL,
+        GspBootMethod::Fsp => gh100::GH100_HAL,
     }
 }

-- 
2.54.0