linux-kernel - [PATCH 1/6] gpu: nova-core: print FB sizes, along with ranges

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Message-ID: <20251106035435.619949-2-jhubbard@nvidia.com>
Date: Wed,  5 Nov 2025 19:54:30 -0800
From: John Hubbard <jhubbard@...dia.com>
To: Danilo Krummrich <dakr@...nel.org>
Cc: Alexandre Courbot <acourbot@...dia.com>,
	Joel Fernandes <joelagnelf@...dia.com>,
	Timur Tabi <ttabi@...dia.com>,
	Alistair Popple <apopple@...dia.com>,
	Edwin Peer <epeer@...dia.com>,
	Zhi Wang <zhiw@...dia.com>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Miguel Ojeda <ojeda@...nel.org>,
	Alex Gaynor <alex.gaynor@...il.com>,
	Boqun Feng <boqun.feng@...il.com>,
	Gary Guo <gary@...yguo.net>,
	Björn Roy Baron <bjorn3_gh@...tonmail.com>,
	Benno Lossin <lossin@...nel.org>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	Alice Ryhl <aliceryhl@...gle.com>,
	Trevor Gross <tmgross@...ch.edu>,
	nouveau@...ts.freedesktop.org,
	rust-for-linux@...r.kernel.org,
	LKML <linux-kernel@...r.kernel.org>,
	John Hubbard <jhubbard@...dia.com>
Subject: [PATCH 1/6] gpu: nova-core: print FB sizes, along with ranges

For convenience of the reader: now you can directly see the sizes of
each range. It is suprising just how much this helps.

Sample output:

NovaCore 0000:e1:00.0: FbLayout {
    fb: 0x0..0x3ff800000 (16376 MB),
    vga_workspace: 0x3ff700000..0x3ff800000 (1 MB),
    frts: 0x3ff600000..0x3ff700000 (1 MB),
    boot: 0x3ff5fa000..0x3ff600000 (0 MB),
    elf: 0x3fb960000..0x3ff5f9000 (60 MB),
    wpr2_heap: 0x3f3900000..0x3fb900000 (128 MB),
    wpr2: 0x3f3800000..0x3ff700000 (191 MB),
    heap: 0x3f3700000..0x3f3800000 (1 MB),
    vf_partition_count: 0x0,
    rsvd_size: 0x1a00000,
}

Signed-off-by: John Hubbard <jhubbard@...dia.com>
---
 drivers/gpu/nova-core/fb.rs       | 33 ++++++++++++++++++++++++++++++-
 drivers/gpu/nova-core/gsp/boot.rs |  2 +-
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/nova-core/fb.rs b/drivers/gpu/nova-core/fb.rs
index 10406b6f2e16..004238689f26 100644
--- a/drivers/gpu/nova-core/fb.rs
+++ b/drivers/gpu/nova-core/fb.rs
@@ -87,7 +87,6 @@ pub(crate) fn unregister(&self, bar: &Bar0) {
 /// Layout of the GPU framebuffer memory.
 ///
 /// Contains ranges of GPU memory reserved for a given purpose during the GSP boot process.
-#[derive(Debug)]
 pub(crate) struct FbLayout {
     /// Range of the framebuffer. Starts at `0`.
     pub(crate) fb: Range<u64>,
@@ -107,6 +106,38 @@ pub(crate) struct FbLayout {
     pub(crate) vf_partition_count: u8,
 }
 
+struct RangeWithSize<'a>(&'a Range<u64>);
+
+impl core::fmt::Debug for RangeWithSize<'_> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        if self.0.start == 0 && self.0.end == 0 {
+            write!(f, "0x0..0x0")
+        } else {
+            let size_mb = (self.0.end - self.0.start) >> 20;
+            write!(f, "{:#x}..{:#x} ({} MB)", self.0.start, self.0.end, size_mb)
+        }
+    }
+}
+
+impl core::fmt::Debug for FbLayout {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        f.debug_struct("FbLayout")
+            .field("fb", &RangeWithSize(&self.fb))
+            .field("vga_workspace", &RangeWithSize(&self.vga_workspace))
+            .field("frts", &RangeWithSize(&self.frts))
+            .field("boot", &RangeWithSize(&self.boot))
+            .field("elf", &RangeWithSize(&self.elf))
+            .field("wpr2_heap", &RangeWithSize(&self.wpr2_heap))
+            .field("wpr2", &RangeWithSize(&self.wpr2))
+            .field("heap", &RangeWithSize(&self.heap))
+            .field(
+                "vf_partition_count",
+                &fmt!("{:#x}", self.vf_partition_count),
+            )
+            .finish()
+    }
+}
+
 impl FbLayout {
     /// Computes the FB layout for `chipset`, for running the `bl` GSP bootloader and `gsp` GSP
     /// firmware.
diff --git a/drivers/gpu/nova-core/gsp/boot.rs b/drivers/gpu/nova-core/gsp/boot.rs
index bd3be366526e..c27a90aa782c 100644
--- a/drivers/gpu/nova-core/gsp/boot.rs
+++ b/drivers/gpu/nova-core/gsp/boot.rs
@@ -141,7 +141,7 @@ pub(crate) fn boot(
         )?;
 
         let fb_layout = FbLayout::new(chipset, bar, &gsp_fw)?;
-        dev_dbg!(dev, "{:#x?}\n", fb_layout);
+        dev_dbg!(dev, "{:#?}\n", fb_layout);
 
         Self::run_fwsec_frts(dev, gsp_falcon, bar, &bios, &fb_layout)?;
 
-- 
2.51.2