[PATCH v4 03/11] gpu: nova-core: add Chipset::name() method

[Alexandre Courbot <acourbot@nvidia.com>]

There are a few cases where we need the lowercase name of a given
chipset, notably to resolve firmware files paths for dynamic loading or
to build the module information.

So far, we relied on a static `NAMES` array for the latter, and some
CString hackery for the former.

Replace both with a new `name` const method that returns the lowercase
name of a chipset instance. We can generate it using the `paste!` macro.

Using this method removes the need to create a `CString` when loading
firmware, and lets us remove a couple of utility functions that now have
no user.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpu/nova-core/firmware.rs |  8 +++-----
 drivers/gpu/nova-core/gpu.rs      | 25 +++++++++++++++++--------
 drivers/gpu/nova-core/util.rs     | 20 --------------------
 3 files changed, 20 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/nova-core/firmware.rs b/drivers/gpu/nova-core/firmware.rs
index 2931912ddba0ea1fe6d027ccec70b39cdb40344a..213d4506a53f83e7474861f6f81f033a9760fb61 100644
--- a/drivers/gpu/nova-core/firmware.rs
+++ b/drivers/gpu/nova-core/firmware.rs
@@ -30,9 +30,7 @@ pub(crate) struct Firmware {
 
 impl Firmware {
     pub(crate) fn new(dev: &device::Device, chipset: Chipset, ver: &str) -> Result<Firmware> {
-        let mut chip_name = CString::try_from_fmt(fmt!("{chipset}"))?;
-        chip_name.make_ascii_lowercase();
-        let chip_name = &*chip_name;
+        let chip_name = chipset.name();
 
         let request = |name_| {
             CString::try_from_fmt(fmt!("nvidia/{chip_name}/gsp/{name_}-{ver}.bin"))
@@ -180,8 +178,8 @@ pub(crate) const fn create(
         let mut this = Self(firmware::ModInfoBuilder::new(module_name));
         let mut i = 0;
 
-        while i < gpu::Chipset::NAMES.len() {
-            this = this.make_entry_chipset(gpu::Chipset::NAMES[i]);
+        while i < gpu::Chipset::ALL.len() {
+            this = this.make_entry_chipset(gpu::Chipset::ALL[i].name());
             i += 1;
         }
 
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index cb991c7faef5523459367f3b9a7fd9cc29671b98..444beda52a4166e7052e980231dd870237354c3a 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -10,7 +10,6 @@
 use crate::firmware::{Firmware, FIRMWARE_VERSION};
 use crate::gfw;
 use crate::regs;
-use crate::util;
 use crate::vbios::Vbios;
 use core::fmt;
 
@@ -28,13 +27,23 @@ impl Chipset {
                 $( Chipset::$variant, )*
             ];
 
-            pub(crate) const NAMES: [&'static str; Self::ALL.len()] = [
-                $( util::const_bytes_to_str(
-                        util::to_lowercase_bytes::<{ stringify!($variant).len() }>(
-                            stringify!($variant)
-                        ).as_slice()
-                ), )*
-            ];
+            ::kernel::macros::paste!(
+            /// Returns the name of this chipset, in lowercase.
+            ///
+            /// # Examples
+            ///
+            /// ```
+            /// let chipset = Chipset::GA102;
+            /// assert_eq!(chipset.name(), "ga102");
+            /// ```
+            pub(crate) const fn name(&self) -> &'static str {
+                match *self {
+                $(
+                    Chipset::$variant => stringify!([<$variant:lower>]),
+                )*
+                }
+            }
+            );
         }
 
         // TODO[FPRI]: replace with something like derive(FromPrimitive)
diff --git a/drivers/gpu/nova-core/util.rs b/drivers/gpu/nova-core/util.rs
index 76cedf3710d7bb248f62ed50381a70f8ffb3f19a..bf35f00cb732ee4fa6644854718a0ad99051666a 100644
--- a/drivers/gpu/nova-core/util.rs
+++ b/drivers/gpu/nova-core/util.rs
@@ -3,26 +3,6 @@
 use kernel::prelude::*;
 use kernel::time::{Delta, Instant, Monotonic};
 
-pub(crate) const fn to_lowercase_bytes<const N: usize>(s: &str) -> [u8; N] {
-    let src = s.as_bytes();
-    let mut dst = [0; N];
-    let mut i = 0;
-
-    while i < src.len() && i < N {
-        dst[i] = (src[i] as char).to_ascii_lowercase() as u8;
-        i += 1;
-    }
-
-    dst
-}
-
-pub(crate) const fn const_bytes_to_str(bytes: &[u8]) -> &str {
-    match core::str::from_utf8(bytes) {
-        Ok(string) => string,
-        Err(_) => kernel::build_error!("Bytes are not valid UTF-8."),
-    }
-}
-
 /// Wait until `cond` is true or `timeout` elapsed.
 ///
 /// When `cond` evaluates to `Some`, its return value is returned.

-- 
2.51.0