[PATCH v2 11/21] gpu: nova-core: wait for GFW_BOOT completion

[Alexandre Courbot <acourbot@nvidia.com>]

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   | 43 ++++++++++++++++++++++++++++++++++++++
 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, 61 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..31a313a0652cfb16c490a346d06c47ca5b0edde9
--- /dev/null
+++ b/drivers/gpu/nova-core/devinit.rs
@@ -0,0 +1,43 @@
+// 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::NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_PRIV_LEVEL_MASK::read(b)
+                    .read_protection_level0()
+                    && (regs::NV_PGC6_AON_SECURE_SCRATCH_GROUP_05::read(b).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 b1ee465de907432325c4d0e0dead3a52e81ed067..ac246d08141e95927a25cada4ecb7e23156ac6b4 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;
@@ -181,6 +182,10 @@ 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, 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 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