[PATCH 2/2] gpu: nova-core: use kernel lossless integer conversion module

[Alexandre Courbot <acourbot@nvidia.com>]

The `kernel` crate now features a copy of our lossless integer
conversion routines. Switch to the kernel version and remove our own.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpu/nova-core/falcon.rs                    |  10 +-
 drivers/gpu/nova-core/falcon/fsp.rs                |   2 +-
 drivers/gpu/nova-core/fb.rs                        |   2 +-
 drivers/gpu/nova-core/fb/hal/gb100.rs              |   6 +-
 drivers/gpu/nova-core/firmware.rs                  |   8 +-
 drivers/gpu/nova-core/firmware/booter.rs           |  10 +-
 drivers/gpu/nova-core/firmware/fwsec.rs            |   2 +-
 drivers/gpu/nova-core/firmware/fwsec/bootloader.rs |   2 +-
 drivers/gpu/nova-core/firmware/gsp.rs              |   2 +-
 drivers/gpu/nova-core/firmware/riscv.rs            |   6 +-
 drivers/gpu/nova-core/fsp.rs                       |   2 +-
 drivers/gpu/nova-core/gsp.rs                       |   2 +-
 drivers/gpu/nova-core/gsp/cmdq.rs                  |   4 +-
 drivers/gpu/nova-core/gsp/fw.rs                    |   8 +-
 drivers/gpu/nova-core/gsp/sequencer.rs             |   2 +-
 drivers/gpu/nova-core/num.rs                       | 211 ---------------------
 drivers/gpu/nova-core/vbios.rs                     |   2 +-
 17 files changed, 35 insertions(+), 246 deletions(-)

diff --git a/drivers/gpu/nova-core/falcon.rs b/drivers/gpu/nova-core/falcon.rs
index 94c7696a6493..3133c6e2f229 100644
--- a/drivers/gpu/nova-core/falcon.rs
+++ b/drivers/gpu/nova-core/falcon.rs
@@ -23,6 +23,10 @@
         },
         Io,
     },
+    num::{
+        self,
+        FromSafeCast, //
+    },
     prelude::*,
     sync::aref::ARef,
     time::Delta,
@@ -33,11 +37,7 @@
     driver::Bar0,
     falcon::hal::LoadMethod,
     gpu::Chipset,
-    num::{
-        self,
-        FromSafeCast, //
-    },
-    regs,
+    regs, //
 };
 
 pub(crate) mod fsp;
diff --git a/drivers/gpu/nova-core/falcon/fsp.rs b/drivers/gpu/nova-core/falcon/fsp.rs
index 52cdb84ef0e8..aad919c8471d 100644
--- a/drivers/gpu/nova-core/falcon/fsp.rs
+++ b/drivers/gpu/nova-core/falcon/fsp.rs
@@ -16,6 +16,7 @@
         },
         Io, //
     },
+    num,
     prelude::*,
     time::Delta,
 };
@@ -28,7 +29,6 @@
         PFalcon2Base,
         PFalconBase, //
     },
-    num,
     regs, //
 };
 
diff --git a/drivers/gpu/nova-core/fb.rs b/drivers/gpu/nova-core/fb.rs
index 725e428154cf..a635be13d0d0 100644
--- a/drivers/gpu/nova-core/fb.rs
+++ b/drivers/gpu/nova-core/fb.rs
@@ -10,6 +10,7 @@
     dma::CoherentHandle,
     fmt,
     io::Io,
+    num::FromSafeCast,
     prelude::*,
     ptr::{
         Alignable,
@@ -23,7 +24,6 @@
     firmware::gsp::GspFirmware,
     gpu::Chipset,
     gsp,
-    num::FromSafeCast,
     regs, //
 };
 
diff --git a/drivers/gpu/nova-core/fb/hal/gb100.rs b/drivers/gpu/nova-core/fb/hal/gb100.rs
index 6e0eba101ca1..91461433c5d0 100644
--- a/drivers/gpu/nova-core/fb/hal/gb100.rs
+++ b/drivers/gpu/nova-core/fb/hal/gb100.rs
@@ -11,7 +11,10 @@
         },
         Io, //
     },
-    num::Bounded,
+    num::{
+        usize_into_u32,
+        Bounded, //
+    },
     prelude::*,
     ptr::{
         const_align_up,
@@ -23,7 +26,6 @@
 use crate::{
     driver::Bar0,
     fb::hal::FbHal,
-    num::usize_into_u32,
     regs, //
 };
 
diff --git a/drivers/gpu/nova-core/firmware.rs b/drivers/gpu/nova-core/firmware.rs
index 1e89390209f5..03571251b490 100644
--- a/drivers/gpu/nova-core/firmware.rs
+++ b/drivers/gpu/nova-core/firmware.rs
@@ -10,6 +10,10 @@
 use kernel::{
     device,
     firmware,
+    num::{
+        FromSafeCast,
+        IntoSafeCast, //
+    },
     prelude::*,
     str::CString,
     transmute::FromBytes, //
@@ -21,10 +25,6 @@
         FalconFirmware, //
     },
     gpu,
-    num::{
-        FromSafeCast,
-        IntoSafeCast, //
-    },
 };
 
 pub(crate) mod booter;
diff --git a/drivers/gpu/nova-core/firmware/booter.rs b/drivers/gpu/nova-core/firmware/booter.rs
index d9313ac361af..0645677dcc30 100644
--- a/drivers/gpu/nova-core/firmware/booter.rs
+++ b/drivers/gpu/nova-core/firmware/booter.rs
@@ -10,6 +10,10 @@
 use kernel::{
     device,
     dma::Coherent,
+    num::{
+        FromSafeCast,
+        IntoSafeCast, //
+    },
     prelude::*,
     transmute::FromBytes, //
 };
@@ -31,11 +35,7 @@
         Signed,
         Unsigned, //
     },
-    gpu::Chipset,
-    num::{
-        FromSafeCast,
-        IntoSafeCast, //
-    },
+    gpu::Chipset, //
 };
 
 /// Local convenience function to return a copy of `S` by reinterpreting the bytes starting at
diff --git a/drivers/gpu/nova-core/firmware/fwsec.rs b/drivers/gpu/nova-core/firmware/fwsec.rs
index 199ae2adb664..e856eb698300 100644
--- a/drivers/gpu/nova-core/firmware/fwsec.rs
+++ b/drivers/gpu/nova-core/firmware/fwsec.rs
@@ -19,6 +19,7 @@
         self,
         Device, //
     },
+    num::FromSafeCast,
     prelude::*,
     transmute::{
         AsBytes,
@@ -43,7 +44,6 @@
         Signed,
         Unsigned, //
     },
-    num::FromSafeCast,
     vbios::Vbios,
 };
 
diff --git a/drivers/gpu/nova-core/firmware/fwsec/bootloader.rs b/drivers/gpu/nova-core/firmware/fwsec/bootloader.rs
index 039920dc340b..7d82c0ca33a5 100644
--- a/drivers/gpu/nova-core/firmware/fwsec/bootloader.rs
+++ b/drivers/gpu/nova-core/firmware/fwsec/bootloader.rs
@@ -17,6 +17,7 @@
         register::WithBase, //
         Io,
     },
+    num::FromSafeCast,
     prelude::*,
     ptr::{
         Alignable,
@@ -51,7 +52,6 @@
         FIRMWARE_VERSION, //
     },
     gpu::Chipset,
-    num::FromSafeCast,
     regs,
 };
 
diff --git a/drivers/gpu/nova-core/firmware/gsp.rs b/drivers/gpu/nova-core/firmware/gsp.rs
index 99a302bae567..87ed9d4ede08 100644
--- a/drivers/gpu/nova-core/firmware/gsp.rs
+++ b/drivers/gpu/nova-core/firmware/gsp.rs
@@ -8,6 +8,7 @@
         DataDirection,
         DmaAddress, //
     },
+    num::FromSafeCast,
     prelude::*,
     scatterlist::{
         Owned,
@@ -25,7 +26,6 @@
         Chipset, //
     },
     gsp::GSP_PAGE_SIZE,
-    num::FromSafeCast,
 };
 
 /// GSP firmware with 3-level radix page tables for the GSP bootloader.
diff --git a/drivers/gpu/nova-core/firmware/riscv.rs b/drivers/gpu/nova-core/firmware/riscv.rs
index 2afa7f36404e..572c2815a053 100644
--- a/drivers/gpu/nova-core/firmware/riscv.rs
+++ b/drivers/gpu/nova-core/firmware/riscv.rs
@@ -7,14 +7,12 @@
     device,
     dma::Coherent,
     firmware::Firmware,
+    num::FromSafeCast,
     prelude::*,
     transmute::FromBytes, //
 };
 
-use crate::{
-    firmware::BinFirmware,
-    num::FromSafeCast, //
-};
+use crate::firmware::BinFirmware;
 
 /// Descriptor for microcode running on a RISC-V core.
 #[repr(C)]
diff --git a/drivers/gpu/nova-core/fsp.rs b/drivers/gpu/nova-core/fsp.rs
index 8fc243c66e35..ae529652b3eb 100644
--- a/drivers/gpu/nova-core/fsp.rs
+++ b/drivers/gpu/nova-core/fsp.rs
@@ -11,6 +11,7 @@
     device,
     dma::Coherent,
     io::poll::read_poll_timeout,
+    num,
     prelude::*,
     ptr::{
         Alignable,
@@ -42,7 +43,6 @@
         NvdmHeader,
         NvdmType, //
     },
-    num,
     regs, //
 };
 
diff --git a/drivers/gpu/nova-core/gsp.rs b/drivers/gpu/nova-core/gsp.rs
index 69175ca3315c..75f7bfe50976 100644
--- a/drivers/gpu/nova-core/gsp.rs
+++ b/drivers/gpu/nova-core/gsp.rs
@@ -11,6 +11,7 @@
         CoherentBox,
         DmaAddress, //
     },
+    num,
     pci,
     prelude::*,
     transmute::{
@@ -36,7 +37,6 @@
         GspArgumentsPadded,
         LibosMemoryRegionInitArgument, //
     },
-    num,
 };
 
 pub(crate) const GSP_PAGE_SHIFT: usize = 12;
diff --git a/drivers/gpu/nova-core/gsp/cmdq.rs b/drivers/gpu/nova-core/gsp/cmdq.rs
index 070de0731e95..513542ed7924 100644
--- a/drivers/gpu/nova-core/gsp/cmdq.rs
+++ b/drivers/gpu/nova-core/gsp/cmdq.rs
@@ -16,6 +16,7 @@
         Io, //
     },
     new_mutex,
+    num,
     prelude::*,
     ptr,
     sync::{
@@ -26,7 +27,7 @@
     transmute::{
         AsBytes,
         FromBytes, //
-    },
+    }, //
 };
 
 use continuation::{
@@ -50,7 +51,6 @@
         GSP_PAGE_SHIFT,
         GSP_PAGE_SIZE, //
     },
-    num,
     regs,
     sbuffer::SBufferIter, //
 };
diff --git a/drivers/gpu/nova-core/gsp/fw.rs b/drivers/gpu/nova-core/gsp/fw.rs
index 4db0cfa4dc4d..755015a2eff1 100644
--- a/drivers/gpu/nova-core/gsp/fw.rs
+++ b/drivers/gpu/nova-core/gsp/fw.rs
@@ -11,6 +11,10 @@
 
 use kernel::{
     dma::Coherent,
+    num::{
+        self,
+        FromSafeCast, //
+    },
     prelude::*,
     ptr::{
         Alignable,
@@ -38,10 +42,6 @@
         cmdq::Cmdq, //
         GSP_PAGE_SIZE,
     },
-    num::{
-        self,
-        FromSafeCast, //
-    },
 };
 
 // TODO: Replace with `IoView` projections once available.
diff --git a/drivers/gpu/nova-core/gsp/sequencer.rs b/drivers/gpu/nova-core/gsp/sequencer.rs
index e0850d21adca..2ee84178628f 100644
--- a/drivers/gpu/nova-core/gsp/sequencer.rs
+++ b/drivers/gpu/nova-core/gsp/sequencer.rs
@@ -10,6 +10,7 @@
         poll::read_poll_timeout,
         Io, //
     },
+    num::FromSafeCast,
     prelude::*,
     time::{
         delay::fsleep,
@@ -32,7 +33,6 @@
         },
         fw,
     },
-    num::FromSafeCast,
     sbuffer::SBufferIter,
 };
 
diff --git a/drivers/gpu/nova-core/num.rs b/drivers/gpu/nova-core/num.rs
index 6eb174d136ab..3921ef6f238e 100644
--- a/drivers/gpu/nova-core/num.rs
+++ b/drivers/gpu/nova-core/num.rs
@@ -5,217 +5,6 @@
 //! This is essentially a staging module for code to mature until it can be moved to the `kernel`
 //! crate.
 
-use kernel::{
-    macros::paste,
-    prelude::*, //
-};
-
-/// Implements safe `as` conversion functions from a given type into a series of target types.
-///
-/// These functions can be used in place of `as`, with the guarantee that they will be lossless.
-macro_rules! impl_safe_as {
-    ($from:ty as { $($into:ty),* }) => {
-        $(
-        paste! {
-            #[doc = ::core::concat!(
-                "Losslessly converts a [`",
-                ::core::stringify!($from),
-                "`] into a [`",
-                ::core::stringify!($into),
-                "`].")]
-            ///
-            /// This conversion is allowed as it is always lossless. Prefer this over the `as`
-            /// keyword to ensure no lossy casts are performed.
-            ///
-            /// This is for use from a `const` context. For non `const` use, prefer the
-            /// [`FromSafeCast`] and [`IntoSafeCast`] traits.
-            ///
-            /// # Examples
-            ///
-            /// ```
-            /// use crate::num;
-            ///
-            #[doc = ::core::concat!(
-                "assert_eq!(num::",
-                ::core::stringify!($from),
-                "_as_",
-                ::core::stringify!($into),
-                "(1",
-                ::core::stringify!($from),
-                "), 1",
-                ::core::stringify!($into),
-                ");")]
-            /// ```
-            #[allow(unused)]
-            #[inline(always)]
-            pub(crate) const fn [<$from _as_ $into>](value: $from) -> $into {
-                ::kernel::build_assert::static_assert!(size_of::<$into>() >= size_of::<$from>());
-
-                value as $into
-            }
-        }
-        )*
-    };
-}
-
-impl_safe_as!(u8 as { u16, u32, u64, usize });
-impl_safe_as!(u16 as { u32, u64, usize });
-impl_safe_as!(u32 as { u64, usize } );
-// `u64` and `usize` have the same size on 64-bit platforms.
-#[cfg(CONFIG_64BIT)]
-impl_safe_as!(u64 as { usize } );
-
-// A `usize` fits into a `u64` on 32 and 64-bit platforms.
-#[cfg(any(CONFIG_32BIT, CONFIG_64BIT))]
-impl_safe_as!(usize as { u64 });
-
-// A `usize` fits into a `u32` on 32-bit platforms.
-#[cfg(CONFIG_32BIT)]
-impl_safe_as!(usize as { u32 });
-
-/// Extension trait providing guaranteed lossless cast to `Self` from `T`.
-///
-/// The standard library's `From` implementations do not cover conversions that are not portable or
-/// future-proof. For instance, even though it is safe today, `From<usize>` is not implemented for
-/// [`u64`] because of the possibility to support larger-than-64bit architectures in the future.
-///
-/// The workaround is to either deal with the error handling of [`TryFrom`] for an operation that
-/// technically cannot fail, or to use the `as` keyword, which can silently strip data if the
-/// destination type is smaller than the source.
-///
-/// Both options are hardly acceptable for the kernel. It is also a much more architecture
-/// dependent environment, supporting only 32 and 64 bit architectures, with some modules
-/// explicitly depending on a specific bus width that could greatly benefit from infallible
-/// conversion operations.
-///
-/// Thus this extension trait that provides, for the architecture the kernel is built for, safe
-/// conversion between types for which such cast is lossless.
-///
-/// In other words, this trait is implemented if, for the current build target and with `t: T`, the
-/// `t as Self` operation is completely lossless.
-///
-/// Prefer this over the `as` keyword to ensure no lossy casts are performed.
-///
-/// If you need to perform a conversion in `const` context, use [`u64_as_usize`], [`u32_as_usize`],
-/// [`usize_as_u64`], etc.
-///
-/// # Examples
-///
-/// ```
-/// use crate::num::FromSafeCast;
-///
-/// assert_eq!(usize::from_safe_cast(0xf00u32), 0xf00u32 as usize);
-/// ```
-pub(crate) trait FromSafeCast<T> {
-    /// Create a `Self` from `value`. This operation is guaranteed to be lossless.
-    fn from_safe_cast(value: T) -> Self;
-}
-
-impl FromSafeCast<usize> for u64 {
-    fn from_safe_cast(value: usize) -> Self {
-        usize_as_u64(value)
-    }
-}
-
-#[cfg(CONFIG_32BIT)]
-impl FromSafeCast<usize> for u32 {
-    fn from_safe_cast(value: usize) -> Self {
-        usize_as_u32(value)
-    }
-}
-
-impl FromSafeCast<u32> for usize {
-    fn from_safe_cast(value: u32) -> Self {
-        u32_as_usize(value)
-    }
-}
-
-#[cfg(CONFIG_64BIT)]
-impl FromSafeCast<u64> for usize {
-    fn from_safe_cast(value: u64) -> Self {
-        u64_as_usize(value)
-    }
-}
-
-/// Counterpart to the [`FromSafeCast`] trait, i.e. this trait is to [`FromSafeCast`] what [`Into`]
-/// is to [`From`].
-///
-/// See the documentation of [`FromSafeCast`] for the motivation.
-///
-/// # Examples
-///
-/// ```
-/// use crate::num::IntoSafeCast;
-///
-/// assert_eq!(0xf00u32.into_safe_cast(), 0xf00u32 as usize);
-/// ```
-pub(crate) trait IntoSafeCast<T> {
-    /// Convert `self` into a `T`. This operation is guaranteed to be lossless.
-    fn into_safe_cast(self) -> T;
-}
-
-/// Reverse operation for types implementing [`FromSafeCast`].
-impl<S, T> IntoSafeCast<T> for S
-where
-    T: FromSafeCast<S>,
-{
-    fn into_safe_cast(self) -> T {
-        T::from_safe_cast(self)
-    }
-}
-
-/// Implements lossless conversion of a constant from a larger type into a smaller one.
-macro_rules! impl_const_into {
-    ($from:ty => { $($into:ty),* }) => {
-        $(
-        paste! {
-            #[doc = ::core::concat!(
-                "Performs a build-time safe conversion of a [`",
-                ::core::stringify!($from),
-                "`] constant value into a [`",
-                ::core::stringify!($into),
-                "`].")]
-            ///
-            /// This checks at compile-time that the conversion is lossless, and triggers a build
-            /// error if it isn't.
-            ///
-            /// # Examples
-            ///
-            /// ```
-            /// use crate::num;
-            ///
-            /// // Succeeds because the value of the source fits into the destination's type.
-            #[doc = ::core::concat!(
-                "assert_eq!(num::",
-                ::core::stringify!($from),
-                "_into_",
-                ::core::stringify!($into),
-                "::<1",
-                ::core::stringify!($from),
-                ">(), 1",
-                ::core::stringify!($into),
-                ");")]
-            /// ```
-            #[allow(unused)]
-            pub(crate) const fn [<$from _into_ $into>]<const N: $from>() -> $into {
-                // Make sure that the target type is smaller than the source one.
-                static_assert!($from::BITS >= $into::BITS);
-                // CAST: we statically enforced above that `$from` is larger than `$into`, so the
-                // `as` conversion will be lossless.
-                build_assert!(N >= $into::MIN as $from && N <= $into::MAX as $from);
-
-                N as $into
-            }
-        }
-        )*
-    };
-}
-
-impl_const_into!(usize => { u8, u16, u32 });
-impl_const_into!(u64 => { u8, u16, u32 });
-impl_const_into!(u32 => { u8, u16 });
-impl_const_into!(u16 => { u8 });
-
 /// Creates an enum type associated to a [`Bounded`](kernel::num::Bounded), with a [`From`]
 /// conversion to the associated `Bounded` and either a [`TryFrom`] or `From` conversion from the
 /// associated `Bounded`.
diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs
index c6e6bfcd6a1f..9bce9a4b2286 100644
--- a/drivers/gpu/nova-core/vbios.rs
+++ b/drivers/gpu/nova-core/vbios.rs
@@ -5,6 +5,7 @@
 use kernel::{
     device,
     io::Io,
+    num::FromSafeCast,
     prelude::*,
     ptr::{
         Alignable,
@@ -26,7 +27,6 @@
         FalconUCodeDescV2,
         FalconUCodeDescV3, //
     },
-    num::FromSafeCast,
 };
 
 /// BIOS Image Type from PCI Data Structure code_type field.

-- 
2.55.0