Automatically select between the "10" and "16" variants of command set,

based on the device size.

src/drivers/block/scsi.c

 }
 
 /**
- * Read block from SCSI device
+ * Read block from SCSI device using READ (10)
  *
  * @v blockdev		Block device
  * @v block		LBA block number
  * @v buffer		Data buffer
  * @ret rc		Return status code
  */
-static int scsi_read ( struct block_device *blockdev, uint64_t block,
-		       unsigned long count, userptr_t buffer ) {
+static int scsi_read_10 ( struct block_device *blockdev, uint64_t block,
+			  unsigned long count, userptr_t buffer ) {
+	struct scsi_device *scsi = block_to_scsi ( blockdev );
+	struct scsi_command command;
+	struct scsi_cdb_read_10 *cdb = &command.cdb.read10;
+
+	/* Issue READ (10) */
+	memset ( &command, 0, sizeof ( command ) );
+	cdb->opcode = SCSI_OPCODE_READ_10;
+	cdb->lba = cpu_to_be32 ( block );
+	cdb->len = cpu_to_be16 ( count );
+	command.data_in = buffer;
+	command.data_in_len = ( count * blockdev->blksize );
+	return scsi_command ( scsi, &command );
+}
+
+/**
+ * Read block from SCSI device using READ (16)
+ *
+ * @v blockdev		Block device
+ * @v block		LBA block number
+ * @v count		Block count
+ * @v buffer		Data buffer
+ * @ret rc		Return status code
+ */
+static int scsi_read_16 ( struct block_device *blockdev, uint64_t block,
+			  unsigned long count, userptr_t buffer ) {
 	struct scsi_device *scsi = block_to_scsi ( blockdev );
 	struct scsi_command command;
 	struct scsi_cdb_read_16 *cdb = &command.cdb.read16;
 }
 
 /**
- * Write block to SCSI device
+ * Write block to SCSI device using WRITE (10)
  *
  * @v blockdev		Block device
  * @v block		LBA block number
  * @v buffer		Data buffer
  * @ret rc		Return status code
  */
-static int scsi_write ( struct block_device *blockdev, uint64_t block,
-		        unsigned long count, userptr_t buffer ) {
+static int scsi_write_10 ( struct block_device *blockdev, uint64_t block,
+			   unsigned long count, userptr_t buffer ) {
+	struct scsi_device *scsi = block_to_scsi ( blockdev );
+	struct scsi_command command;
+	struct scsi_cdb_write_10 *cdb = &command.cdb.write10;
+
+	/* Issue WRITE (10) */
+	memset ( &command, 0, sizeof ( command ) );
+	cdb->opcode = SCSI_OPCODE_WRITE_10;
+	cdb->lba = cpu_to_be32 ( block );
+	cdb->len = cpu_to_be16 ( count );
+	command.data_out = buffer;
+	command.data_out_len = ( count * blockdev->blksize );
+	return scsi_command ( scsi, &command );
+}
+
+/**
+ * Write block to SCSI device using WRITE (16)
+ *
+ * @v blockdev		Block device
+ * @v block		LBA block number
+ * @v count		Block count
+ * @v buffer		Data buffer
+ * @ret rc		Return status code
+ */
+static int scsi_write_16 ( struct block_device *blockdev, uint64_t block,
+			   unsigned long count, userptr_t buffer ) {
 	struct scsi_device *scsi = block_to_scsi ( blockdev );
 	struct scsi_command command;
 	struct scsi_cdb_write_16 *cdb = &command.cdb.write16;
 }
 
 /**
- * Read capacity of SCSI device
+ * Initialise SCSI device
  *
- * @v blockdev		Block device
+ * @v scsi		SCSI device
  * @ret rc		Return status code
+ *
+ * Initialises a SCSI device.  The scsi_device::command and
+ * scsi_device::lun fields must already be filled in.  This function
+ * will configure scsi_device::blockdev, including issuing a READ
+ * CAPACITY call to determine the block size and total device size.
  */
-static int scsi_read_capacity ( struct block_device *blockdev ) {
+int init_scsidev ( struct scsi_device *scsi ) {
 	int rc;
 
 	/* Issue a theoretically extraneous READ CAPACITY (10)
 	 * (power-on occurred)" that some dumb targets insist on
 	 * sending as an error at start of day.
 	 */
-	scsi_read_capacity_10 ( blockdev );
+	scsi_read_capacity_10 ( &scsi->blockdev );
 
 	/* Try READ CAPACITY (10), which is a mandatory command, first. */
-	if ( ( rc = scsi_read_capacity_10 ( blockdev ) ) != 0 )
+	scsi->blockdev.read = scsi_read_10;
+	scsi->blockdev.write = scsi_write_10;
+	if ( ( rc = scsi_read_capacity_10 ( &scsi->blockdev ) ) != 0 )
 		return rc;
 
 	/* If capacity range was exceeded (i.e. capacity.lba was
 	 * READ CAPACITY (16) instead.  READ CAPACITY (16) is not
 	 * mandatory, so we can't just use it straight off.
 	 */
-	if ( blockdev->blocks == 0 ) {
-		if ( ( rc = scsi_read_capacity_16 ( blockdev ) ) != 0 )
+	if ( scsi->blockdev.blocks == 0 ) {
+		scsi->blockdev.read = scsi_read_16;
+		scsi->blockdev.write = scsi_write_16;
+		if ( ( rc = scsi_read_capacity_16 ( &scsi->blockdev ) ) != 0 )
 			return rc;
 	}
 
 	return 0;
 }
-
-/**
- * Initialise SCSI device
- *
- * @v scsi		SCSI device
- * @ret rc		Return status code
- *
- * Initialises a SCSI device.  The scsi_device::command and
- * scsi_device::lun fields must already be filled in.  This function
- * will configure scsi_device::blockdev, including issuing a READ
- * CAPACITY call to determine the block size and total device size.
- */
-int init_scsidev ( struct scsi_device *scsi ) {
-	/** Fill in read and write methods, and get device capacity */
-	scsi->blockdev.read = scsi_read;
-	scsi->blockdev.write = scsi_write;
-	return scsi_read_capacity ( &scsi->blockdev );
-}

src/include/gpxe/scsi.h

  * @{
  */
 
+#define SCSI_OPCODE_READ_10		0x28	/**< READ (10) */
 #define SCSI_OPCODE_READ_16		0x88	/**< READ (16) */
+#define SCSI_OPCODE_WRITE_10		0x2a	/**< WRITE (10) */
 #define SCSI_OPCODE_WRITE_16		0x8a	/**< WRITE (16) */
 #define SCSI_OPCODE_READ_CAPACITY_10	0x25	/**< READ CAPACITY (10) */
 #define SCSI_OPCODE_SERVICE_ACTION_IN	0x9e	/**< SERVICE ACTION IN */
  * @{
  */
 
+/** A SCSI "READ (10)" CDB */
+struct scsi_cdb_read_10 {
+	/** Opcode (0x28) */
+	uint8_t opcode;
+	/** Flags */
+	uint8_t flags;
+	/** Start address
+	 *
+	 * This is a logical block number, in big-endian order.
+	 */
+	uint32_t lba;
+	/** Group number */
+	uint8_t group;
+	/** Transfer length
+	 *
+	 * This is a logical block count, in big-endian order.
+	 */
+	uint16_t len;
+	/** Control byte */
+	uint8_t control;
+} __attribute__ (( packed ));
+
 /** A SCSI "READ (16)" CDB */
 struct scsi_cdb_read_16 {
 	/** Opcode (0x88) */
 	uint8_t control;
 } __attribute__ (( packed ));
 
+/** A SCSI "WRITE (10)" CDB */
+struct scsi_cdb_write_10 {
+	/** Opcode (0x2a) */
+	uint8_t opcode;
+	/** Flags */
+	uint8_t flags;
+	/** Start address
+	 *
+	 * This is a logical block number, in big-endian order.
+	 */
+	uint32_t lba;
+	/** Group number */
+	uint8_t group;
+	/** Transfer length
+	 *
+	 * This is a logical block count, in big-endian order.
+	 */
+	uint16_t len;
+	/** Control byte */
+	uint8_t control;
+} __attribute__ (( packed ));
+
 /** A SCSI "WRITE (16)" CDB */
 struct scsi_cdb_write_16 {
 	/** Opcode (0x8a) */
 
 /** A SCSI Command Data Block */
 union scsi_cdb {
+	struct scsi_cdb_read_10 read10;
 	struct scsi_cdb_read_16 read16;
+	struct scsi_cdb_write_10 write10;
 	struct scsi_cdb_write_16 write16;
 	struct scsi_cdb_read_capacity_10 readcap10;
 	struct scsi_cdb_read_capacity_16 readcap16;