[PATCH 08/16] gpu: nova-core: wait for GFW_BOOT completion

Alexandre Courbot
2025-04-20T12:20:19Z

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@nvidia.com>
---
drivers/gpu/nova-core/devinit.rs | 40 ++++++++++++++++++++++++++++++++++++++
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, 58 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..ee5685aff845aa97d6b0fbe9528df9a7ba274b2c
--- /dev/null
+++ b/drivers/gpu/nova-core/devinit.rs
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Methods for device initialization.
+
+use kernel::bindings;
+use kernel::devres::Devres;
+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: &Devres<Bar0>) -> Result<()> {
+ let mut timeout = 2000;
+
+ loop {
+ let gfw_booted = with_bar!(
+ bar,
+ |b| regs::Pgc6AonSecureScratchGroup05PrivLevelMask::read(b)
+ .read_protection_level0_enabled()
+ && (regs::Pgc6AonSecureScratchGroup05::read(b).value() & 0xff) == 0xff
+ )?;
+
+ if gfw_booted {
+ return Ok(());
+ }
+
+ if timeout == 0 {
+ return Err(ETIMEDOUT);
+ }
+ timeout -= 1;
+
+ // 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 866c5992b9eb27735975bb4948e522bc01fadaa2..1f7799692a0ab042f2540e01414f5ca347ae9ecc 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;
@@ -168,6 +169,10 @@ 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(|_| pr_err!("GFW boot did not complete"))?;
+
Ok(pin_init!(Self { spec, bar, fw }))
}
}
diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs
index 0eecd612e34efc046dad852e6239de6ffa5fdd62..878161e060f54da7738c656f6098936a62dcaa93 100644
--- a/drivers/gpu/nova-core/nova_core.rs
+++ b/drivers/gpu/nova-core/nova_core.rs
@@ -20,6 +20,7 @@ macro_rules! with_bar {
}
}

+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 e315a3011660df7f18c0a3e0582b5845545b36e2..fd7096f0ddd4af90114dd1119d9715d2cd3aa2ac 100644
--- a/drivers/gpu/nova-core/regs.rs
+++ b/drivers/gpu/nova-core/regs.rs
@@ -13,3 +13,14 @@
7:4 major_rev => as u8, "major revision of the chip";
28:20 chipset => try_into Chipset, "chipset model"
);
+
+/* GC6 */
+
+register!(Pgc6AonSecureScratchGroup05PrivLevelMask@0x00118128;
+ 0:0 read_protection_level0_enabled => as_bit bool
+);
+
+/* TODO: This is an array of registers. */
+register!(Pgc6AonSecureScratchGroup05@0x00118234;
+ 31:0 value => as u32
+);

--
2.49.0