Addressing review comments.

third_party/libtock-drivers/src/crp.rs

@@ -5,7 +5,35 @@ const DRIVER_NUMBER: usize = 0x00008;
 
 mod command_nr {
     pub const AVAILABLE: usize = 0;
-    pub const PROTECT: usize = 1;
+    pub const GET_PROTECTION: usize = 1;
+    pub const SET_PROTECTION: usize = 2;
+}
+
+#[derive(PartialOrd, PartialEq)]
+pub enum ProtectionLevel {
+    /// Unsupported feature
+    Unknown = 0,
+    /// This should be the factory default for the chip.
+    NoProtection = 1,
+    /// At this level, only JTAG/SWD are disabled but other debugging
+    /// features may still be enabled.
+    JtagDisabled = 2,
+    /// This is the maximum level of protection the chip supports.
+    /// At this level, JTAG and all other features are expected to be
+    /// disabled and only a full chip erase may allow to recover from
+    /// that state.
+    FullyLocked = 0xff,
+}
+
+impl From<usize> for ProtectionLevel {
+    fn from(value: usize) -> Self {
+        match value {
+            1 => ProtectionLevel::NoProtection,
+            2 => ProtectionLevel::JtagDisabled,
+            0xff => ProtectionLevel::FullyLocked,
+            _ => ProtectionLevel::Unknown,
+        }
+    }
 }
 
 pub fn is_available() -> TockResult<()> {
@@ -13,7 +41,12 @@ pub fn is_available() -> TockResult<()> {
     Ok(())
 }
 
-pub fn protect() -> TockResult<()> {
-    syscalls::command(DRIVER_NUMBER, command_nr::PROTECT, 0, 0)?;
+pub fn get_protection() -> TockResult<ProtectionLevel> {
+    let current_level = syscalls::command(DRIVER_NUMBER, command_nr::GET_PROTECTION, 0, 0)?;
+    Ok(current_level.into())
+}
+
+pub fn set_protection(level: ProtectionLevel) -> TockResult<()> {
+    syscalls::command(DRIVER_NUMBER, command_nr::SET_PROTECTION, level as usize, 0)?;
     Ok(())
 }