[PATCH v3 1/3] gpu: nova-core: move GSP unload state to a pinned Gpu subobject

[Alexandre Courbot <acourbot@nvidia.com>]

`Gpu` currently owns the state needed to unload the GSP directly. This
means that `unload_bundle` has to be the last initialized field: once GSP
boot succeeds, any later initialization failure would leave `Gpu`
partially initialized, and its `PinnedDrop` implementation would not run.

This prevents adding fallible `Gpu` fields that need to query the GSP
after it has booted.

Move the GSP state and unload bundle into a dedicated pinned
`GspResources` object. Once that subobject has been initialized, its
`PinnedDrop` implementation will run even if initialization of a later
`Gpu` field fails, ensuring that the GSP unload sequence is executed.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>
---
 drivers/gpu/nova-core/gpu.rs | 104 +++++++++++++++++++++++++------------------
 1 file changed, 60 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 6a9572107cf3..acee9a3ab37f 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -263,35 +263,62 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     }
 }
 
-/// Structure holding the resources required to operate the GPU.
+/// Self-contained resources to operate and drop the GSP.
 #[pin_data(PinnedDrop)]
-pub(crate) struct Gpu<'gpu> {
+struct GspResources<'gpu> {
     /// Device owning the GPU.
     device: &'gpu device::Device<device::Bound>,
-    spec: Spec,
     /// MMIO mapping of PCI BAR 0.
     bar: Bar0<'gpu>,
-    /// System memory page required for flushing all pending GPU-side memory writes done through
-    /// PCIE into system memory, via sysmembar (A GPU-initiated HW memory-barrier operation).
-    sysmem_flush: SysmemFlush<'gpu>,
     /// GSP falcon instance, used for GSP boot up and cleanup.
     gsp_falcon: Falcon<GspFalcon>,
     /// SEC2 falcon instance, used for GSP boot up and cleanup.
     sec2_falcon: Falcon<Sec2Falcon>,
-    /// GSP runtime data. Temporarily an empty placeholder.
+    /// GSP runtime data.
     #[pin]
     gsp: Gsp,
     /// GSP unload firmware bundle, if any.
     unload_bundle: Option<gsp::UnloadBundle>,
 }
 
+/// Structure holding the resources required to operate the GPU.
+#[pin_data]
+pub(crate) struct Gpu<'gpu> {
+    spec: Spec,
+    /// GSP and its resources.
+    #[pin]
+    gsp_resources: GspResources<'gpu>,
+    /// System memory page required for flushing all pending GPU-side memory writes done through
+    /// PCIE into system memory, via sysmembar (A GPU-initiated HW memory-barrier operation).
+    ///
+    /// Must be kept declared *after* `gsp_resources`, as the latter's `PinnedDrop` implementation
+    /// requires the sysmem flush page to be in place.
+    sysmem_flush: SysmemFlush<'gpu>,
+}
+
+#[pinned_drop]
+impl PinnedDrop for GspResources<'_> {
+    fn drop(self: Pin<&mut Self>) {
+        let this = self.project();
+        let device = *this.device;
+        let bar = *this.bar;
+        let bundle = this.unload_bundle.take();
+
+        let _ = this
+            .gsp
+            .as_ref()
+            .get_ref()
+            .unload(device, bar, &*this.gsp_falcon, &*this.sec2_falcon, bundle)
+            .inspect_err(|e| dev_err!(device, "failed to unload GSP: {:?}\n", e));
+    }
+}
+
 impl<'gpu> Gpu<'gpu> {
     pub(crate) fn new(
         pdev: &'gpu pci::Device<device::Core<'_>>,
         bar: Bar0<'gpu>,
     ) -> impl PinInit<Self, Error> + 'gpu {
         try_pin_init!(Self {
-            device: pdev.as_ref(),
             spec: Spec::new(pdev.as_ref(), bar).inspect(|spec| {
                 dev_info!(pdev,"NVIDIA ({})\n", spec);
             })?,
@@ -309,46 +336,35 @@ pub(crate) fn new(
                     .inspect_err(|_| dev_err!(pdev, "GFW boot did not complete\n"))?;
             },
 
+            // Initialize this early because `gsp_resources` depends on it.
             sysmem_flush: SysmemFlush::register(pdev.as_ref(), bar, spec.chipset)?,
 
-            gsp_falcon: Falcon::new(
-                pdev.as_ref(),
-                spec.chipset,
-            )
-            .inspect(|falcon| falcon.clear_swgen0_intr(bar))?,
+            gsp_resources <- try_pin_init!(GspResources {
+                device: pdev.as_ref(),
 
-            sec2_falcon: Falcon::new(pdev.as_ref(), spec.chipset)?,
-
-            gsp <- Gsp::new(pdev),
-
-            // This member must be initialized last, so the `UnloadBundle` can never be dropped from
-            // outside of the constructed `Gpu`, ensuring that the unload sequence is properly run
-            // in case of failure.
-            unload_bundle: gsp.boot(GspBootContext {
-                pdev,
                 bar,
-                chipset: spec.chipset,
-                gsp_falcon,
-                sec2_falcon,
-            })?,
-            bar,
+
+                gsp_falcon: Falcon::new(
+                    pdev.as_ref(),
+                    spec.chipset,
+                )
+                .inspect(|falcon| falcon.clear_swgen0_intr(bar))?,
+
+                sec2_falcon: Falcon::new(pdev.as_ref(), spec.chipset)?,
+
+                gsp <- Gsp::new(pdev),
+
+                // This member must be initialized last, so the `UnloadBundle` can never be dropped
+                // from outside of the constructed `GspResources`, ensuring that the unload sequence
+                // is properly run in case of failure.
+                unload_bundle: gsp.boot(GspBootContext {
+                    pdev,
+                    bar,
+                    chipset: spec.chipset,
+                    gsp_falcon,
+                    sec2_falcon,
+                })?,
+            }),
         })
     }
 }
-
-#[pinned_drop]
-impl PinnedDrop for Gpu<'_> {
-    fn drop(self: Pin<&mut Self>) {
-        let this = self.project();
-        let device = *this.device;
-        let bar = *this.bar;
-        let bundle = this.unload_bundle.take();
-
-        let _ = this
-            .gsp
-            .as_ref()
-            .get_ref()
-            .unload(device, bar, &*this.gsp_falcon, &*this.sec2_falcon, bundle)
-            .inspect_err(|e| dev_err!(device, "failed to unload GSP: {:?}\n", e));
-    }
-}

-- 
2.54.0