[PATCH v8 10/25] gpu: nova-core: mm: Add GpuMm centralized memory manager

[Joel Fernandes <joelagnelf@nvidia.com>]

Introduce GpuMm as the centralized GPU memory manager that owns:
- Buddy allocator for VRAM allocation.
- PRAMIN window for direct VRAM access.
- TLB manager for translation buffer operations.

This provides clean ownership model where GpuMm provides accessor
methods for its components that can be used for memory management
operations.

Cc: Nikola Djukic <ndjukic@nvidia.com>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
 drivers/gpu/nova-core/gpu.rs | 18 ++++++++++
 drivers/gpu/nova-core/mm.rs  | 66 ++++++++++++++++++++++++++++++++++--
 2 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 5e084ec7c926..ed6c5f63b249 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -4,8 +4,13 @@
     device,
     devres::Devres,
     fmt,
+    gpu::buddy::GpuBuddyParams,
     pci,
     prelude::*,
+    sizes::{
+        SZ_1M,
+        SZ_4K, //
+    },
     sync::Arc, //
 };
 
@@ -22,6 +27,7 @@
         commands::GetGspStaticInfoReply,
         Gsp, //
     },
+    mm::GpuMm,
     regs,
 };
 
@@ -252,6 +258,9 @@ pub(crate) struct Gpu {
     gsp_falcon: Falcon<GspFalcon>,
     /// SEC2 falcon instance, used for GSP boot up and cleanup.
     sec2_falcon: Falcon<Sec2Falcon>,
+    /// GPU memory manager owning memory management resources.
+    #[pin]
+    mm: GpuMm,
     /// GSP runtime data. Temporarily an empty placeholder.
     #[pin]
     gsp: Gsp,
@@ -286,6 +295,15 @@ pub(crate) fn new<'a>(
 
             sec2_falcon: Falcon::new(pdev.as_ref(), spec.chipset)?,
 
+            // Create GPU memory manager owning memory management resources.
+            // This will be initialized with the usable VRAM region from GSP in a later
+            // patch. For now, we use a placeholder of 1MB.
+            mm <- GpuMm::new(devres_bar.clone(), GpuBuddyParams {
+                base_offset_bytes: 0,
+                physical_memory_size_bytes: SZ_1M as u64,
+                chunk_size_bytes: SZ_4K as u64,
+            })?,
+
             gsp <- Gsp::new(pdev),
 
             gsp_static_info: { gsp.boot(pdev, bar, spec.chipset, gsp_falcon, sec2_falcon)?.0 },
diff --git a/drivers/gpu/nova-core/mm.rs b/drivers/gpu/nova-core/mm.rs
index ca685b5a44f3..a3c84738bac0 100644
--- a/drivers/gpu/nova-core/mm.rs
+++ b/drivers/gpu/nova-core/mm.rs
@@ -7,9 +7,71 @@
 pub(crate) mod pramin;
 pub(crate) mod tlb;
 
-use kernel::sizes::SZ_4K;
+use kernel::{
+    devres::Devres,
+    gpu::buddy::{
+        GpuBuddy,
+        GpuBuddyParams, //
+    },
+    prelude::*,
+    sizes::SZ_4K,
+    sync::Arc, //
+};
 
-use crate::num::u64_as_usize;
+use crate::{
+    driver::Bar0,
+    num::u64_as_usize, //
+};
+
+pub(crate) use tlb::Tlb;
+
+/// GPU Memory Manager - owns all core MM components.
+///
+/// Provides centralized ownership of memory management resources:
+/// - [`GpuBuddy`] allocator for VRAM page table allocation.
+/// - [`pramin::Pramin`] for direct VRAM access.
+/// - [`Tlb`] manager for translation buffer flush operations.
+#[pin_data]
+pub(crate) struct GpuMm {
+    buddy: GpuBuddy,
+    #[pin]
+    pramin: pramin::Pramin,
+    #[pin]
+    tlb: Tlb,
+}
+
+impl GpuMm {
+    /// Create a pin-initializer for `GpuMm`.
+    pub(crate) fn new(
+        bar: Arc<Devres<Bar0>>,
+        buddy_params: GpuBuddyParams,
+    ) -> Result<impl PinInit<Self>> {
+        let buddy = GpuBuddy::new(buddy_params)?;
+        let tlb_init = Tlb::new(bar.clone());
+        let pramin_init = pramin::Pramin::new(bar)?;
+
+        Ok(pin_init!(Self {
+            buddy,
+            pramin <- pramin_init,
+            tlb <- tlb_init,
+        }))
+    }
+
+    /// Access the [`GpuBuddy`] allocator.
+    pub(crate) fn buddy(&self) -> &GpuBuddy {
+        &self.buddy
+    }
+
+    /// Access the [`pramin::Pramin`].
+    pub(crate) fn pramin(&self) -> &pramin::Pramin {
+        &self.pramin
+    }
+
+    /// Access the [`Tlb`] manager.
+    pub(crate) fn tlb(&self) -> &Tlb {
+        &self.tlb
+    }
+}
 
 /// Page size in bytes (4 KiB).
 pub(crate) const PAGE_SIZE: usize = SZ_4K;
-- 
2.34.1