Implement proper MSC error handling

embassy-usb/src/class/msc/subclass/scsi/block_device.rs

@@ -1,19 +1,42 @@
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum BlockDeviceError {
-    // TODO
+    /// Block device is not present and cannot be accessed.
+    ///
+    /// SCSI NOT READY 3Ah/00h MEDIUM NOT PRESENT
+    MediumNotPresent,
+    /// Logical Block Address is out of range
+    ///
+    /// SCSI ILLEGAL REQUEST 21h/00h LOGICAL BLOCK ADDRESS OUT OF RANGE
+    LbaOutOfRange,
+    /// Unrecoverable hardware error
+    ///
+    /// SCSI HARDWARE ERROR 00h/00h NO ADDITIONAL SENSE INFORMATION
+    HardwareError,
+    /// SCSI MEDIUM ERROR 11h/00h UNRECOVERED READ ERROR
+    ReadError,
+    /// SCSI MEDIUM ERROR 0Ch/00h WRITE ERROR
+    WriteError,
+    /// SCSI MEDIUM ERROR 51h/00h ERASE FAILURE
+    EraseError,
 }
 
 pub trait BlockDevice {
+    /// Called for periodic `TEST UNIT READY` SCSI requests.
+    ///
+    /// Should return error if device is not ready (i.e. [BlockDeviceError::MediumRemoved] if SD card is not present).
+    fn status(&self) -> Result<(), BlockDeviceError>;
+
     /// The number of bytes per block. This determines the size of the buffer passed
-    /// to read/write functions
-    fn block_size(&self) -> usize;
+    /// to read/write functions.
+    fn block_size(&self) -> Result<usize, BlockDeviceError>;
 
     /// Number of blocks in device (max LBA index)
-    fn num_blocks(&self) -> u32;
+    fn max_lba(&self) -> Result<u32, BlockDeviceError>;
 
     /// Read the block indicated by `lba` into the provided buffer
-    fn read_block(&self, lba: u32, block: &mut [u8]) -> Result<(), BlockDeviceError>;
+    async fn read_block(&self, lba: u32, block: &mut [u8]) -> Result<(), BlockDeviceError>;
 
     /// Write the `block` buffer to the block indicated by `lba`
-    fn write_block(&mut self, lba: u32, block: &[u8]) -> Result<(), BlockDeviceError>;
+    async fn write_block(&mut self, lba: u32, block: &[u8]) -> Result<(), BlockDeviceError>;
 }