[PATCH v10 08/21] 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/Kconfig         |  1 +
 drivers/gpu/nova-core/gpu.rs          | 34 ++++++++++++-
 drivers/gpu/nova-core/gsp/commands.rs |  2 -
 drivers/gpu/nova-core/mm.rs           | 70 ++++++++++++++++++++++++++-
 4 files changed, 102 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/nova-core/Kconfig b/drivers/gpu/nova-core/Kconfig
index a4f2380654e2..6513007bf66f 100644
--- a/drivers/gpu/nova-core/Kconfig
+++ b/drivers/gpu/nova-core/Kconfig
@@ -4,6 +4,7 @@ config NOVA_CORE
 	depends on PCI
 	depends on RUST
 	select AUXILIARY_BUS
+	select GPU_BUDDY
 	select RUST_FW_LOADER_ABSTRACTIONS
 	default n
 	help
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index b4da4a1ae156..c49fa9c380b8 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -4,10 +4,13 @@
     device,
     devres::Devres,
     fmt,
+    gpu::buddy::GpuBuddyParams,
     io::Io,
     num::Bounded,
     pci,
     prelude::*,
+    ptr::Alignment,
+    sizes::SZ_4K,
     sync::Arc, //
 };
 
@@ -25,6 +28,7 @@
         commands::GetGspStaticInfoReply,
         Gsp, //
     },
+    mm::GpuMm,
     regs,
 };
 
@@ -238,6 +242,9 @@ 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,
@@ -274,7 +281,32 @@ pub(crate) fn new<'a>(
 
             gsp <- Gsp::new(pdev),
 
-            gsp_static_info: { gsp.boot(pdev, bar, spec.chipset, gsp_falcon, sec2_falcon)? },
+            gsp_static_info: {
+                let info = gsp.boot(pdev, bar, spec.chipset, gsp_falcon, sec2_falcon)?;
+
+                dev_info!(
+                    pdev.as_ref(),
+                    "Using FB region: {:#x}..{:#x}\n",
+                    info.usable_fb_region.start,
+                    info.usable_fb_region.end
+                );
+
+                info
+            },
+
+            // Create GPU memory manager owning memory management resources.
+            mm <- {
+                let usable_vram = &gsp_static_info.usable_fb_region;
+
+                // PRAMIN covers all physical VRAM (including GSP-reserved areas
+                // above the usable region, e.g. the BAR1 page directory).
+                let pramin_vram_region = 0..gsp_static_info.total_fb_end;
+                GpuMm::new(devres_bar.clone(), GpuBuddyParams {
+                    base_offset: usable_vram.start,
+                    size: usable_vram.end - usable_vram.start,
+                    chunk_size: Alignment::new::<SZ_4K>(),
+                }, pramin_vram_region)?
+            },
 
             bar: devres_bar,
         })
diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index 5e0649024637..ec03bf94b34e 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -194,10 +194,8 @@ fn init(&self) -> impl Init<Self::Command, Self::InitError> {
 pub(crate) struct GetGspStaticInfoReply {
     gpu_name: [u8; 64],
     /// Usable FB (VRAM) region for driver memory allocation.
-    #[expect(dead_code)]
     pub(crate) usable_fb_region: Range<u64>,
     /// End of VRAM.
-    #[expect(dead_code)]
     pub(crate) total_fb_end: u64,
 }
 
diff --git a/drivers/gpu/nova-core/mm.rs b/drivers/gpu/nova-core/mm.rs
index cfe9cbe11d57..3c34d7f05555 100644
--- a/drivers/gpu/nova-core/mm.rs
+++ b/drivers/gpu/nova-core/mm.rs
@@ -7,9 +7,75 @@
 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`.
+    ///
+    /// `pramin_vram_region` is the full physical VRAM range (including GSP-reserved
+    /// areas). PRAMIN window accesses are validated against this range.
+    pub(crate) fn new(
+        bar: Arc<Devres<Bar0>>,
+        buddy_params: GpuBuddyParams,
+        pramin_vram_region: core::ops::Range<u64>,
+    ) -> Result<impl PinInit<Self>> {
+        let buddy = GpuBuddy::new(buddy_params)?;
+        let tlb_init = Tlb::new(bar.clone());
+        let pramin_init = pramin::Pramin::new(bar, pramin_vram_region)?;
+
+        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