linux-kernel - [PATCH v3 09/19] gpu: nova-core: wait for GFW

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Message-Id: <20250507-nova-frts-v3-9-fcb02749754d@nvidia.com>
Date: Wed, 07 May 2025 22:52:36 +0900
From: Alexandre Courbot <acourbot@...dia.com>
To: 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 <benno.lossin@...ton.me>, 
 Andreas Hindborg <a.hindborg@...nel.org>, Alice Ryhl <aliceryhl@...gle.com>, 
 Trevor Gross <tmgross@...ch.edu>, Danilo Krummrich <dakr@...nel.org>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 Jonathan Corbet <corbet@....net>
Cc: John Hubbard <jhubbard@...dia.com>, Ben Skeggs <bskeggs@...dia.com>, 
 Joel Fernandes <joelagnelf@...dia.com>, Timur Tabi <ttabi@...dia.com>, 
 Alistair Popple <apopple@...dia.com>, linux-kernel@...r.kernel.org, 
 rust-for-linux@...r.kernel.org, nouveau@...ts.freedesktop.org, 
 dri-devel@...ts.freedesktop.org, Alexandre Courbot <acourbot@...dia.com>
Subject: [PATCH v3 09/19] gpu: nova-core: wait for GFW_BOOT completion

Upon reset, the GPU executes the GFW_BOOT firmware in order to
initialize its base parameters such as clocks. The driver must ensure
that this step is completed before using the hardware.

Signed-off-by: Alexandre Courbot <acourbot@...dia.com>
---
 drivers/gpu/nova-core/devinit.rs   | 38 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/nova-core/driver.rs    |  2 +-
 drivers/gpu/nova-core/gpu.rs       |  5 +++++
 drivers/gpu/nova-core/nova_core.rs |  1 +
 drivers/gpu/nova-core/regs.rs      | 11 +++++++++++
 5 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/nova-core/devinit.rs b/drivers/gpu/nova-core/devinit.rs
new file mode 100644
index 0000000000000000000000000000000000000000..5be2e0344fb651e5e53c9223aefeb5b2d95b8de1
--- /dev/null
+++ b/drivers/gpu/nova-core/devinit.rs
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Methods for device initialization.
+
+use kernel::bindings;
+use kernel::prelude::*;
+
+use crate::driver::Bar0;
+use crate::regs;
+
+/// Wait for devinit FW completion.
+///
+/// Upon reset, the GPU runs some firmware code to setup its core parameters. Most of the GPU is
+/// considered unusable until this step is completed, so it must be waited on very early during
+/// driver initialization.
+pub(crate) fn wait_gfw_boot_completion(bar: &Bar0) -> Result<()> {
+    let mut timeout = 2000;
+
+    loop {
+        let gfw_booted = regs::NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_PRIV_LEVEL_MASK::read(bar)
+            .read_protection_level0()
+            && (regs::NV_PGC6_AON_SECURE_SCRATCH_GROUP_05::read(bar).value() & 0xff) == 0xff;
+
+        if gfw_booted {
+            return Ok(());
+        }
+
+        if timeout == 0 {
+            return Err(ETIMEDOUT);
+        }
+        timeout -= 1;
+
+        // TODO: use `read_poll_timeout` once it is available.
+        // (https://lore.kernel.org/lkml/20250220070611.214262-8-fujita.tomonori@gmail.com/)
+        // SAFETY: msleep should be safe to call with any parameter.
+        unsafe { bindings::msleep(2) };
+    }
+}
diff --git a/drivers/gpu/nova-core/driver.rs b/drivers/gpu/nova-core/driver.rs
index a08fb6599267a960f0e07b6efd0e3b6cdc296aa4..752ba4b0fcfe8d835d366570bb2f807840a196da 100644
--- a/drivers/gpu/nova-core/driver.rs
+++ b/drivers/gpu/nova-core/driver.rs
@@ -10,7 +10,7 @@ pub(crate) struct NovaCore {
     pub(crate) gpu: Gpu,
 }
 
-const BAR0_SIZE: usize = 8;
+const BAR0_SIZE: usize = 0x1000000;
 pub(crate) type Bar0 = pci::Bar<BAR0_SIZE>;
 
 kernel::pci_device_table!(
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 9c6a9270ffa374bd386af352f6ad9b857f9c5f8d..a9fcf74717791dc7e23678869bf84f61e51873e2 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -2,6 +2,7 @@
 
 use kernel::{device, devres::Devres, error::code::*, pci, prelude::*};
 
+use crate::devinit;
 use crate::driver::Bar0;
 use crate::firmware::Firmware;
 use crate::regs;
@@ -182,6 +183,10 @@ pub(crate) fn new(
             spec.revision
         );
 
+        // We must wait for GFW_BOOT completion before doing any significant setup on the GPU.
+        devinit::wait_gfw_boot_completion(bar)
+            .inspect_err(|_| dev_err!(pdev.as_ref(), "GFW boot did not complete"))?;
+
         Ok(pin_init!(Self {
             spec,
             bar: devres_bar,
diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs
index a91cd924054b49966937a8db6aab9cd0614f10de..3d75e7acc6e0ddcfa142b1fb134cb5c966aaf472 100644
--- a/drivers/gpu/nova-core/nova_core.rs
+++ b/drivers/gpu/nova-core/nova_core.rs
@@ -2,6 +2,7 @@
 
 //! Nova Core GPU Driver
 
+mod devinit;
 mod driver;
 mod firmware;
 mod gpu;
diff --git a/drivers/gpu/nova-core/regs.rs b/drivers/gpu/nova-core/regs.rs
index bfb9555b203ff880c0fc373bb22e5ce6048015d4..401d885539cee03cbe732102f5e2233785a7b284 100644
--- a/drivers/gpu/nova-core/regs.rs
+++ b/drivers/gpu/nova-core/regs.rs
@@ -38,3 +38,14 @@ pub(crate) fn chipset(self) -> Result<Chipset, Error> {
             .and_then(Chipset::try_from)
     }
 }
+
+/* PGC6 */
+
+register!(NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_PRIV_LEVEL_MASK @ 0x00118128 {
+    0:0     read_protection_level0 as bool;
+});
+
+// TODO: This is an array of registers.
+register!(NV_PGC6_AON_SECURE_SCRATCH_GROUP_05 @ 0x00118234 {
+    31:0    value as u32;
+});

-- 
2.49.0