seam cleanup: /src generic-only; drop set_max from the trait

Per the seam audit: keep /src purely the generic contract and move everything
unlocker-specific into its module.

- ld's error type moves src/error.rs -> src/ld/error.rs; it owns the conversions
  From<scsi::ScsiError> (transport fault in) and From<ld::Error> for UnlockError
  (outcome out). src/scsi.rs keeps only the generic transport contract + a
  generic ScsiError; the trait no longer references any concrete error.
- Remove set_max_read_speed from the Unlocker trait — raising read speed is
  drive tuning, NOT bus removal. libfreemkv will issue a generic SET CD SPEED
  itself at drive-open (tracked).

29 tests pass.

src/ld/error.rs

@@ -1,6 +1,8 @@
-//! Internal error type shared by the unlocker modules (firmware / handshake /
-//! bus-auth). Distinct from [`crate::UnlockError`], which is the unlock OUTCOME
-//! the consumer sees; this is the low-level error the SCSI/crypto code uses.
+//! ld's internal error type for the firmware-unlock SCSI/handshake code.
+//! Distinct from [`crate::UnlockError`] (the unlock OUTCOME the consumer sees);
+//! this is the low-level error ld's code uses. Maps both ways: a generic
+//! [`crate::scsi::ScsiError`] transport fault converts IN, and an `Error`
+//! converts OUT to the contract's `UnlockError`.
 
 pub type Result<T> = std::result::Result<T, Error>;
 
@@ -47,3 +49,28 @@ impl Error {
         )
     }
 }
+
+/// A generic transport fault from the SCSI contract converts into ld's error
+/// (the opcode is unknown at the transport level).
+impl From<crate::scsi::ScsiError> for Error {
+    fn from(e: crate::scsi::ScsiError) -> Self {
+        Error::ScsiError {
+            opcode: 0,
+            status: e.status,
+            sense: e.sense,
+        }
+    }
+}
+
+/// ld's internal error converts OUT to the contract outcome: a dead bus is a
+/// hard `Transport` abort; any other firmware failure means "this unlocker
+/// didn't apply" → the consumer falls through to the next unlocker.
+impl From<Error> for crate::UnlockError {
+    fn from(e: Error) -> Self {
+        if e.is_transport_failure() {
+            crate::UnlockError::Transport
+        } else {
+            crate::UnlockError::NotApplicable
+        }
+    }
+}

src/ld/mod.rs

@@ -7,10 +7,11 @@
 //! reporting the OEM Volume ID.
 
 mod cdb;
+mod error;
 mod platform;
 mod profile;
 
-use crate::error::Result;
+use crate::ld::error::Result;
 use crate::scsi::{DataDirection, ScsiTransport};
 use crate::{DriveId, UnlockCtx, UnlockError, Unlocked, Unlocker};
 
@@ -122,21 +123,6 @@ impl Unlocker for LibreDrive {
             drive_unlocked: true,
         })
     }
-
-    /// Raise the drive to its max read speed via the matched profile's
-    /// `set_speed_max_cdb` (no-op if the profile carries none).
-    fn set_max_read_speed(&self, scsi: &mut dyn ScsiTransport, ctx: &UnlockCtx) -> Result<()> {
-        let Some(m) = profile::find_bundled(ctx.drive_id) else {
-            return Ok(());
-        };
-        let Some(cdb) = m.profile.set_speed_max_cdb else {
-            return Ok(());
-        };
-        let mut buf = [0u8; 0];
-        scsi.execute(&cdb, DataDirection::None, &mut buf, 5_000)?;
-        tracing::debug!(target: "freemkv::drive", phase = "set_max_read_speed", "issued SET CD SPEED (max) via unlocker");
-        Ok(())
-    }
 }
 
 #[cfg(test)]
@@ -164,7 +150,7 @@ mod tests {
             _dir: DataDirection,
             data: &mut [u8],
             _timeout_ms: u32,
-        ) -> Result<ScsiResult> {
+        ) -> crate::scsi::Result<ScsiResult> {
             let n = self.payload.len().min(data.len());
             data[..n].copy_from_slice(&self.payload[..n]);
             Ok(ScsiResult {
@@ -271,67 +257,4 @@ mod tests {
             .expect_err("no profile → NotApplicable");
         assert_eq!(err, UnlockError::NotApplicable);
     }
-
-    /// Records the CDB issued so the speed test can assert the exact CDB.
-    struct RecordingTransport {
-        last_cdb: Vec<u8>,
-        calls: usize,
-    }
-    impl ScsiTransport for RecordingTransport {
-        fn execute(
-            &mut self,
-            cdb: &[u8],
-            _dir: DataDirection,
-            _data: &mut [u8],
-            _timeout_ms: u32,
-        ) -> Result<ScsiResult> {
-            self.last_cdb = cdb.to_vec();
-            self.calls += 1;
-            Ok(ScsiResult {
-                status: 0,
-                bytes_transferred: 0,
-                sense: [0u8; 32],
-            })
-        }
-    }
-
-    /// A matched drive whose profile carries `set_speed_max_cdb` → that exact CDB.
-    #[test]
-    fn set_max_read_speed_issues_profile_cdb() {
-        let m = profile::find_bundled(&known_vid_drive_id()).expect("profile match");
-        let expected = m
-            .profile
-            .set_speed_max_cdb
-            .expect("test fixture drive must carry a set_speed_max_cdb");
-
-        let mut t = RecordingTransport {
-            last_cdb: Vec::new(),
-            calls: 0,
-        };
-        LibreDrive::new()
-            .set_max_read_speed(&mut t, &ctx(&known_vid_drive_id()))
-            .expect("set_max_read_speed ok");
-        assert_eq!(t.calls, 1, "exactly one CDB issued");
-        assert_eq!(
-            t.last_cdb,
-            expected.to_vec(),
-            "the profile's set_speed_max_cdb"
-        );
-    }
-
-    /// A drive with no matching profile → no-op: no CDB issued, Ok(()).
-    #[test]
-    fn set_max_read_speed_no_profile_is_noop() {
-        let mut t = RecordingTransport {
-            last_cdb: Vec::new(),
-            calls: 0,
-        };
-        LibreDrive::new()
-            .set_max_read_speed(
-                &mut t,
-                &ctx(&make_drive_id("FAKE-VND", "9.99", "XX12345", "")),
-            )
-            .expect("no-profile is a no-op Ok(())");
-        assert_eq!(t.calls, 0, "no profile → no CDB issued");
-    }
 }

src/ld/platform/mod.rs

@@ -2,7 +2,7 @@
 
 pub mod mt1959;
 
-use crate::error::Result;
+use crate::ld::error::Result;
 use crate::scsi::ScsiTransport;
 
 pub(crate) trait PlatformDriver: Send {

src/ld/platform/mt1959/mod.rs

@@ -4,7 +4,7 @@ mod variant_a;
 mod variant_b;
 
 use super::PlatformDriver;
-use crate::error::{Error, Result};
+use crate::ld::error::{Error, Result};
 use crate::ld::profile::DriveProfile;
 use crate::scsi::{self, DataDirection, ScsiTransport};
 
@@ -414,7 +414,7 @@ mod tests {
             _dir: DataDirection,
             data: &mut [u8],
             _timeout_ms: u32,
-        ) -> Result<ScsiResult> {
+        ) -> crate::scsi::Result<ScsiResult> {
             let n = self.response.len().min(data.len());
             data[..n].copy_from_slice(&self.response[..n]);
             Ok(ScsiResult {
@@ -437,7 +437,7 @@ mod tests {
             _dir: DataDirection,
             _data: &mut [u8],
             _timeout_ms: u32,
-        ) -> Result<ScsiResult> {
+        ) -> crate::scsi::Result<ScsiResult> {
             self.cdbs.push(cdb.to_vec());
             // Empty response → do_unlock's signature check fails, so the unlock
             // loop exhausts — but the firmware-load CDBs (incl. the F1 verify)

src/ld/platform/mt1959/variant_a.rs

@@ -3,7 +3,7 @@
 //! WRITE_BUFFER (0x3B) → verify READ_BUFFER (0x45) → unlock × 2
 
 use super::Mt1959;
-use crate::error::Result;
+use crate::ld::error::Result;
 use crate::scsi::{DataDirection, ScsiTransport};
 
 use super::SCSI_WRITE_BUFFER;
@@ -17,7 +17,7 @@ const WRITE_BUFFER_MAX_LEN: usize = 0x00FF_FFFF;
 pub(super) fn load_firmware(mt: &mut Mt1959, scsi: &mut dyn ScsiTransport) -> Result<()> {
     let firmware = &mt.profile.firmware;
     if firmware.is_empty() {
-        return Err(crate::error::Error::UnlockFailed);
+        return Err(crate::ld::error::Error::UnlockFailed);
     }
 
     // Upload firmware via WRITE_BUFFER. The CDB's length is a 24-bit field;
@@ -26,7 +26,7 @@ pub(super) fn load_firmware(mt: &mut Mt1959, scsi: &mut dyn ScsiTransport) -> Re
     // length-mismatched command.
     let len = firmware.len();
     if len > WRITE_BUFFER_MAX_LEN {
-        return Err(crate::error::Error::UnlockFailed);
+        return Err(crate::ld::error::Error::UnlockFailed);
     }
     let cdb = [
         SCSI_WRITE_BUFFER,

src/ld/platform/mt1959/variant_b.rs

@@ -3,7 +3,7 @@
 //! MODE SELECT (0x55) → read metadata → WRITE_BUFFER → vendor verify (0xF1) → unlock × 5+1
 
 use super::{Mt1959, SCSI_READ_BUFFER, SCSI_WRITE_BUFFER};
-use crate::error::Result;
+use crate::ld::error::Result;
 use crate::scsi::{DataDirection, ScsiTransport};
 
 const SCSI_MODE_SELECT: u8 = 0x55;
@@ -16,7 +16,7 @@ const VENDOR_VERIFY: [u8; 10] = [0xF1, 0x01, 0x02, 0x00, 0x0D, 0x30, 0x01, 0xF3,
 pub(super) fn load_firmware(mt: &mut Mt1959, scsi: &mut dyn ScsiTransport) -> Result<()> {
     let firmware = &mt.profile.firmware;
     if firmware.is_empty() {
-        return Err(crate::error::Error::UnlockFailed);
+        return Err(crate::ld::error::Error::UnlockFailed);
     }
 
     // Step 1: Upload the firmware via MODE SELECT. The profile's `firmware` is
@@ -27,7 +27,7 @@ pub(super) fn load_firmware(mt: &mut Mt1959, scsi: &mut dyn ScsiTransport) -> Re
     // expressed in the CDB.
     let write_len = firmware.len();
     if write_len > u16::MAX as usize {
-        return Err(crate::error::Error::UnlockFailed);
+        return Err(crate::ld::error::Error::UnlockFailed);
     }
     let mode_select_cdb = [
         SCSI_MODE_SELECT,

src/ld/profile.rs

@@ -1,6 +1,6 @@
 //! Drive profile loading and matching.
 
-use crate::error::{Error, Result};
+use crate::ld::error::{Error, Result};
 use serde::Deserialize;
 
 /// Top-level profiles file — keyed by chipset + variant.

src/lib.rs

@@ -10,7 +10,6 @@
 //! never names an individual unlocker. To remove an unlocker, delete its module
 //! dir and its one line in [`all_unlockers`] — nothing else changes.
 
-pub mod error;
 pub mod scsi;
 
 mod ld;
@@ -91,21 +90,13 @@ pub enum UnlockError {
     Transport,
 }
 
-impl From<error::Error> for UnlockError {
-    fn from(e: error::Error) -> Self {
-        if e.is_transport_failure() {
-            UnlockError::Transport
-        } else {
-            // A logical firmware/handshake failure is not a dead bus — this
-            // unlocker simply didn't apply; the consumer falls through.
-            UnlockError::NotApplicable
-        }
-    }
-}
-
 /// An unlocker removes a drive-level bus-encryption barrier. Implementors are
 /// the self-contained modules in this crate; the consumer only ever sees the
-/// trait, via [`all_unlockers`].
+/// trait, via [`all_unlockers`]. (Each module owns its own conversion from its
+/// internal error to [`UnlockError`].)
+///
+/// NOTE: drive tuning (e.g. SET CD SPEED to lift riplock) is deliberately NOT
+/// here — that is the consumer's concern, not bus removal.
 pub trait Unlocker: Send + Sync {
     /// True if this unlocker applies to the given context (drive id + disc kind).
     fn matches(&self, ctx: &UnlockCtx) -> bool;
@@ -115,14 +106,6 @@ pub trait Unlocker: Send + Sync {
         scsi: &mut dyn ScsiTransport,
         ctx: &UnlockCtx,
     ) -> std::result::Result<Unlocked, UnlockError>;
-    /// Best-effort: raise the drive to its maximum read speed. Default no-op.
-    fn set_max_read_speed(
-        &self,
-        _scsi: &mut dyn ScsiTransport,
-        _ctx: &UnlockCtx,
-    ) -> error::Result<()> {
-        Ok(())
-    }
 }
 
 /// Every unlocker, in dispatch order (firmware → cert → css). This is the ONLY

src/scsi.rs

@@ -18,6 +18,17 @@ pub struct ScsiResult {
     pub sense: [u8; 32],
 }
 
+/// A transport-layer SCSI failure (the command could not complete — bridge
+/// crash / disconnect), as opposed to a drive sense returned in [`ScsiResult`].
+#[derive(Debug, Clone)]
+pub struct ScsiError {
+    pub status: u8,
+    pub sense: Option<[u8; 32]>,
+}
+
+/// Transport-layer result.
+pub type Result<T> = std::result::Result<T, ScsiError>;
+
 /// The one capability an unlocker needs from the host: run a raw CDB. `Ok` even
 /// on a SCSI sense (inspect `status`); `Err` only on a transport-layer fault.
 pub trait ScsiTransport {
@@ -27,7 +38,7 @@ pub trait ScsiTransport {
         direction: DataDirection,
         data: &mut [u8],
         timeout_ms: u32,
-    ) -> crate::error::Result<ScsiResult>;
+    ) -> Result<ScsiResult>;
 }
 
 /// SCSI status byte for a transport-layer failure (bridge crash / disconnect).