Fix clippy warnings

Fixes warnings:
- deprecated
- clippy::collapsible_else_if
- clippy::empty_loop
- clippy::needless_borrow

The change from `llvm_asm!()` to `asm!()` uses explicit operands to
indicate to Rust that these are memory addresses, allowing it to drop
the casts.

Signed-off-by: Tim Crawford <tcrawford@system76.com>

src/app/bios.rs

@@ -131,7 +131,9 @@ impl BiosComponent {
             }
 
             println!("Halt");
-            loop {}
+            loop {
+                unsafe { asm!("cli", "hlt", options(nomem, nostack)); }
+            }
         } else {
             println!("Failed to locate EC");
         }
@@ -376,7 +378,7 @@ impl Component for BiosComponent {
                     if ! matching {
                         spi.erase(i).unwrap();
                         if ! erased {
-                            spi.write(i, &new_chunk).unwrap();
+                            spi.write(i, new_chunk).unwrap();
                         }
                     }
 

src/app/mod.rs

@@ -290,10 +290,8 @@ fn inner() -> Result<()> {
             if success {
                 if find(IFLASHV).is_ok() {
                     // Do not reset DMI on meer5
-                } else {
-                    if let Err(err) = reset_dmi() {
-                        println!("Failed to reset DMI: {:?}", err);
-                    }
+                } else if let Err(err) = reset_dmi() {
+                    println!("Failed to reset DMI: {:?}", err);
                 }
 
                 if setup_menu {

src/display.rs

@@ -189,22 +189,26 @@ impl<'a> Renderer for ScaledDisplay<'a> {
 #[inline(always)]
 #[cold]
 pub unsafe fn fast_copy(dst: *mut u8, src: *const u8, len: usize) {
-    llvm_asm!("cld
-        rep movsb"
-        :
-        : "{rdi}"(dst as usize), "{rsi}"(src as usize), "{rcx}"(len)
-        : "cc", "memory", "rdi", "rsi", "rcx"
-        : "intel", "volatile");
+    asm!(
+        "cld",
+        "rep movsb [rdi], [rsi]",
+        inout("rdi") dst => _,
+        inout("rsi") src => _,
+        inout("rcx") len => _,
+        options(nostack)
+    );
 }
 
 #[cfg(target_arch = "x86_64")]
 #[inline(always)]
 #[cold]
 pub unsafe fn fast_set32(dst: *mut u32, src: u32, len: usize) {
-    llvm_asm!("cld
-        rep stosd"
-        :
-        : "{rdi}"(dst as usize), "{eax}"(src), "{rcx}"(len)
-        : "cc", "memory", "rdi", "rcx"
-        : "intel", "volatile");
+    asm!(
+        "cld",
+        "rep stosd [rdi], eax",
+        inout("rdi") dst => _,
+        inout("eax") src => _,
+        inout("rcx") len => _,
+        options(nostack)
+    );
 }

src/main.rs

@@ -2,7 +2,7 @@
 
 #![no_std]
 #![no_main]
-#![feature(llvm_asm)]
+#![feature(asm)]
 #![feature(prelude_import)]
 #![feature(try_trait_v2)]
 #![feature(control_flow_enum)]