fix pi-lens warnings: unwraps, shell SC2046, dup code (fmtbuf/scripts/hexdump/cat/ahci/pci)

- memory.rs: self-test Layout::from_size_align no longer panics — the
  test fails cleanly on an invalid layout
- fat.rs: v() no longer unwraps the active-volume slot — invariant
  violation logs + halts instead of panicking mid-disk-io
- strbuf: shared FmtBuf replaces the duplicated PanicBuf/FmtBuf
  (main.rs + sched.rs)
- test-disk.sh: SC2046 — conditional --fresh arg no longer relies on
  word splitting
- scripts: boot.sh/boot-image.sh share lib-boot-args.sh (dup args loop)
- shell: cat/hexdump stdin pairs unified with Option<&str> marker;
  hexdump format_row folded into format_partial
- ahci: read/write_sectors unified behind dma_sectors
- pci: config_read/write share config_addr

1 files changed, 16 insertions, 12 deletions

diff --git a/rsnix/src/pci.rs b/rsnix/src/pci.rs
index 21d7536..b9c2265 100644
--- a/rsnix/src/pci.rs
+++ b/rsnix/src/pci.rs
@@ -46,25 +46,25 @@ fn inl(port: u16) -> u32 {
     val
 }
 
-/// Read a dword from a device's config space (`reg` must be dword-aligned).
-pub fn config_read(bus: u8, device: u8, func: u8, reg: u8) -> u32 {
-    let addr = 0x8000_0000
+/// Encode the PCI config-space port address for (bus, dev, fn, reg);
+/// `reg` must be dword-aligned.
+fn config_addr(bus: u8, device: u8, func: u8, reg: u8) -> u32 {
+    0x8000_0000
         | ((bus as u32) << 16)
         | ((device as u32) << 11)
         | ((func as u32) << 8)
-        | ((reg as u32) & 0xFC);
-    outl(CONFIG_ADDRESS, addr);
+        | ((reg as u32) & 0xFC)
+}
+
+/// Read a dword from a device's config space (`reg` must be dword-aligned).
+pub fn config_read(bus: u8, device: u8, func: u8, reg: u8) -> u32 {
+    outl(CONFIG_ADDRESS, config_addr(bus, device, func, reg));
     inl(CONFIG_DATA)
 }
 
 /// Write a dword to a device's config space (`reg` must be dword-aligned).
 pub fn config_write(bus: u8, device: u8, func: u8, reg: u8, val: u32) {
-    let addr = 0x8000_0000
-        | ((bus as u32) << 16)
-        | ((device as u32) << 11)
-        | ((func as u32) << 8)
-        | ((reg as u32) & 0xFC);
-    outl(CONFIG_ADDRESS, addr);
+    outl(CONFIG_ADDRESS, config_addr(bus, device, func, reg));
     outl(CONFIG_DATA, val)
 }
 
@@ -83,7 +83,11 @@ pub fn bar64(bus: u8, device: u8, func: u8, bar_index: u8) -> Option<u64> {
         0
     };
     let base = ((hi as u64) << 32) | (lo as u64 & 0xFFFF_FFF0);
-    if base == 0 { None } else { Some(base) }
+    if base == 0 {
+        None
+    } else {
+        Some(base)
+    }
 }
 
 /// Enumerate every device/function present on all buses.