Merge pull request #2 from hathach/master

Pulling latest from source

5 files changed, 667 insertions, 690 deletions

diff --git a/src/class/msc/msc.h b/src/class/msc/msc.h
index cba8066b7..84b6e4d79 100644
--- a/src/class/msc/msc.h
+++ b/src/class/msc/msc.h
@@ -24,13 +24,6 @@
  * This file is part of the TinyUSB stack.
  */
 
-/** \ingroup group_class
- *  \defgroup ClassDriver_MSC MassStorage (MSC)
- *  @{ */
-
-/**  \defgroup ClassDriver_MSC_Common Common Definitions
- *  @{ */
-
 #ifndef _TUSB_MSC_H_
 #define _TUSB_MSC_H_
 
@@ -255,7 +248,7 @@ typedef struct TU_ATTR_PACKED
 
   uint8_t : 3;
   uint8_t disable_block_descriptor : 1;
-  uint8_t : 0;
+  uint8_t : 4;
 
   uint8_t page_code : 6;
   uint8_t page_control : 2;
@@ -387,6 +380,3 @@ TU_VERIFY_STATIC(sizeof(scsi_write10_t) == 10, "size is not correct");
 #endif
 
 #endif /* _TUSB_MSC_H_ */
-
-/// @}
-/// @}
diff --git a/src/class/msc/msc_device.c b/src/class/msc/msc_device.c
index 3ff0eba92..014e8b69e 100644
--- a/src/class/msc/msc_device.c
+++ b/src/class/msc/msc_device.c
@@ -28,13 +28,19 @@
 
 #if (TUSB_OPT_DEVICE_ENABLED && CFG_TUD_MSC)
 
-#include "common/tusb_common.h"
-#include "msc_device.h"
+#include "device/usbd.h"
 #include "device/usbd_pvt.h"
+#include "device/dcd.h"         // for faking dcd_event_xfer_complete
+
+#include "msc_device.h"
 
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF
 //--------------------------------------------------------------------+
+
+// Can be selectively disabled to reduce logging when troubleshooting other driver
+#define MSC_DEBUG   2
+
 enum
 {
   MSC_STAGE_CMD  = 0,
@@ -65,36 +71,30 @@ typedef struct
 }mscd_interface_t;
 
 CFG_TUSB_MEM_SECTION CFG_TUSB_MEM_ALIGN static mscd_interface_t _mscd_itf;
-CFG_TUSB_MEM_SECTION CFG_TUSB_MEM_ALIGN static uint8_t _mscd_buf[CFG_TUD_MSC_BUFSIZE];
+CFG_TUSB_MEM_SECTION CFG_TUSB_MEM_ALIGN static uint8_t _mscd_buf[CFG_TUD_MSC_EP_BUFSIZE];
 
 //--------------------------------------------------------------------+
 // INTERNAL OBJECT & FUNCTION DECLARATION
 //--------------------------------------------------------------------+
+static int32_t proc_builtin_scsi(uint8_t lun, uint8_t const scsi_cmd[16], uint8_t* buffer, uint32_t bufsize);
 static void proc_read10_cmd(uint8_t rhport, mscd_interface_t* p_msc);
 static void proc_write10_cmd(uint8_t rhport, mscd_interface_t* p_msc);
 
 static inline uint32_t rdwr10_get_lba(uint8_t const command[])
 {
-  // read10 & write10 has the same format
-  scsi_write10_t* p_rdwr10 = (scsi_write10_t*) command;
-
-  // copy first to prevent mis-aligned access
-  uint32_t lba;
-  memcpy(&lba, &p_rdwr10->lba, 4);
+  // use offsetof to avoid pointer to the odd/unaligned address
+  uint32_t const lba = tu_unaligned_read32(command + offsetof(scsi_write10_t, lba));
 
-  // lba is in Big Endian format
+  // lba is in Big Endian
   return tu_ntohl(lba);
 }
 
 static inline uint16_t rdwr10_get_blockcount(uint8_t const command[])
 {
-  // read10 & write10 has the same format
-  scsi_write10_t* p_rdwr10 = (scsi_write10_t*) command;
-
-  // copy first to prevent mis-aligned access
-  uint16_t block_count;
-  memcpy(&block_count, &p_rdwr10->block_count, 2);
+  // use offsetof to avoid pointer to the odd/misaligned address
+  uint16_t const block_count = tu_unaligned_read16(command + offsetof(scsi_write10_t, block_count));
 
+  // block count is in Big Endian
   return tu_ntohs(block_count);
 }
 
@@ -103,7 +103,7 @@ static inline uint16_t rdwr10_get_blockcount(uint8_t const command[])
 //--------------------------------------------------------------------+
 #if CFG_TUSB_DEBUG >= 2
 
-static lookup_entry_t const _msc_scsi_cmd_lookup[] =
+TU_ATTR_UNUSED static tu_lookup_entry_t const _msc_scsi_cmd_lookup[] =
 {
   { .key = SCSI_CMD_TEST_UNIT_READY              , .data = "Test Unit Ready" },
   { .key = SCSI_CMD_INQUIRY                      , .data = "Inquiry" },
@@ -118,7 +118,7 @@ static lookup_entry_t const _msc_scsi_cmd_lookup[] =
   { .key = SCSI_CMD_WRITE_10                     , .data = "Write10" }
 };
 
-static lookup_table_t const _msc_scsi_cmd_table =
+TU_ATTR_UNUSED static tu_lookup_table_t const _msc_scsi_cmd_table =
 {
   .count = TU_ARRAY_SIZE(_msc_scsi_cmd_lookup),
   .items = _msc_scsi_cmd_lookup
@@ -154,30 +154,43 @@ void mscd_reset(uint8_t rhport)
   tu_memclr(&_mscd_itf, sizeof(mscd_interface_t));
 }
 
-bool mscd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t *p_len)
+uint16_t mscd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t max_len)
 {
   // only support SCSI's BOT protocol
-  TU_ASSERT(MSC_SUBCLASS_SCSI == itf_desc->bInterfaceSubClass &&
-            MSC_PROTOCOL_BOT  == itf_desc->bInterfaceProtocol);
+  TU_VERIFY(TUSB_CLASS_MSC    == itf_desc->bInterfaceClass &&
+            MSC_SUBCLASS_SCSI == itf_desc->bInterfaceSubClass &&
+            MSC_PROTOCOL_BOT  == itf_desc->bInterfaceProtocol, 0);
 
-  mscd_interface_t * p_msc = &_mscd_itf;
+  // msc driver length is fixed
+  uint16_t const drv_len = sizeof(tusb_desc_interface_t) + 2*sizeof(tusb_desc_endpoint_t);
 
-  // Open endpoint pair
-  TU_ASSERT( usbd_open_edpt_pair(rhport, tu_desc_next(itf_desc), 2, TUSB_XFER_BULK, &p_msc->ep_out, &p_msc->ep_in) );
+  // Max length mus be at least 1 interface + 2 endpoints
+  TU_ASSERT(max_len >= drv_len, 0);
 
+  mscd_interface_t * p_msc = &_mscd_itf;
   p_msc->itf_num = itf_desc->bInterfaceNumber;
-  (*p_len) = sizeof(tusb_desc_interface_t) + 2*sizeof(tusb_desc_endpoint_t);
+
+  // Open endpoint pair
+  TU_ASSERT( usbd_open_edpt_pair(rhport, tu_desc_next(itf_desc), 2, TUSB_XFER_BULK, &p_msc->ep_out, &p_msc->ep_in), 0 );
 
   // Prepare for Command Block Wrapper
-  TU_ASSERT( usbd_edpt_xfer(rhport, p_msc->ep_out, (uint8_t*) &p_msc->cbw, sizeof(msc_cbw_t)) );
+  if ( !usbd_edpt_xfer(rhport, p_msc->ep_out, (uint8_t*) &p_msc->cbw, sizeof(msc_cbw_t)) )
+  {
+    TU_LOG_FAILED();
+    TU_BREAKPOINT();
+  }
 
-  return true;
+  return drv_len;
 }
 
-// Handle class control request
+// Invoked when a control transfer occurred on an interface of this class
+// Driver response accordingly to the request and the transfer stage (setup/data/ack)
 // return false to stall control endpoint (e.g unsupported request)
-bool mscd_control_request(uint8_t rhport, tusb_control_request_t const * p_request)
+bool mscd_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_request_t const * p_request)
 {
+  // nothing to do with DATA & ACK stage
+  if (stage != CONTROL_STAGE_SETUP) return true;
+
   // Handle class request only
   TU_VERIFY(p_request->bmRequestType_bit.type == TUSB_REQ_TYPE_CLASS);
 
@@ -207,190 +220,6 @@ bool mscd_control_request(uint8_t rhport, tusb_control_request_t const * p_reque
   return true;
 }
 
-// Invoked when class request DATA stage is finished.
-// return false to stall control endpoint (e.g Host send non-sense DATA)
-bool mscd_control_complete(uint8_t rhport, tusb_control_request_t const * request)
-{
-  (void) rhport;
-  (void) request;
-
-  // nothing to do
-  return true;
-}
-
-// return response's length (copied to buffer). Negative if it is not an built-in command or indicate Failed status (CSW)
-// In case of a failed status, sense key must be set for reason of failure
-int32_t proc_builtin_scsi(uint8_t lun, uint8_t const scsi_cmd[16], uint8_t* buffer, uint32_t bufsize)
-{
-  (void) bufsize; // TODO refractor later
-  int32_t resplen;
-
-  switch ( scsi_cmd[0] )
-  {
-    case SCSI_CMD_TEST_UNIT_READY:
-      resplen = 0;
-      if ( !tud_msc_test_unit_ready_cb(lun) )
-      {
-        // Failed status response
-        resplen = - 1;
-
-        // If sense key is not set by callback, default to Logical Unit Not Ready, Cause Not Reportable
-        if ( _mscd_itf.sense_key == 0 ) tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x04, 0x00);
-      }
-    break;
-
-    case SCSI_CMD_START_STOP_UNIT:
-      resplen = 0;
-
-      if (tud_msc_start_stop_cb)
-      {
-        scsi_start_stop_unit_t const * start_stop = (scsi_start_stop_unit_t const *) scsi_cmd;
-        if ( !tud_msc_start_stop_cb(lun, start_stop->power_condition, start_stop->start, start_stop->load_eject) )
-        {
-          // Failed status response
-          resplen = - 1;
-
-          // If sense key is not set by callback, default to Logical Unit Not Ready, Cause Not Reportable
-          if ( _mscd_itf.sense_key == 0 ) tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x04, 0x00);
-        }
-      }
-    break;
-
-    case SCSI_CMD_READ_CAPACITY_10:
-    {
-      uint32_t block_count;
-      uint32_t block_size;
-      uint16_t block_size_u16;
-
-      tud_msc_capacity_cb(lun, &block_count, &block_size_u16);
-      block_size = (uint32_t) block_size_u16;
-
-      // Invalid block size/count from callback, possibly unit is not ready
-      // stall this request, set sense key to NOT READY
-      if (block_count == 0 || block_size == 0)
-      {
-        resplen = -1;
-
-        // If sense key is not set by callback, default to Logical Unit Not Ready, Cause Not Reportable
-        if ( _mscd_itf.sense_key == 0 ) tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x04, 0x00);
-      }else
-      {
-        scsi_read_capacity10_resp_t read_capa10;
-
-        read_capa10.last_lba = tu_htonl(block_count-1);
-        read_capa10.block_size = tu_htonl(block_size);
-
-        resplen = sizeof(read_capa10);
-        memcpy(buffer, &read_capa10, resplen);
-      }
-    }
-    break;
-
-    case SCSI_CMD_READ_FORMAT_CAPACITY:
-    {
-      scsi_read_format_capacity_data_t read_fmt_capa =
-      {
-          .list_length     = 8,
-          .block_num       = 0,
-          .descriptor_type = 2, // formatted media
-          .block_size_u16  = 0
-      };
-
-      uint32_t block_count;
-      uint16_t block_size;
-
-      tud_msc_capacity_cb(lun, &block_count, &block_size);
-
-      // Invalid block size/count from callback, possibly unit is not ready
-      // stall this request, set sense key to NOT READY
-      if (block_count == 0 || block_size == 0)
-      {
-        resplen = -1;
-
-        // If sense key is not set by callback, default to Logical Unit Not Ready, Cause Not Reportable
-        if ( _mscd_itf.sense_key == 0 ) tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x04, 0x00);
-      }else
-      {
-        read_fmt_capa.block_num = tu_htonl(block_count);
-        read_fmt_capa.block_size_u16 = tu_htons(block_size);
-
-        resplen = sizeof(read_fmt_capa);
-        memcpy(buffer, &read_fmt_capa, resplen);
-      }
-    }
-    break;
-
-    case SCSI_CMD_INQUIRY:
-    {
-      scsi_inquiry_resp_t inquiry_rsp =
-      {
-          .is_removable         = 1,
-          .version              = 2,
-          .response_data_format = 2,
-      };
-
-      // vendor_id, product_id, product_rev is space padded string
-      memset(inquiry_rsp.vendor_id  , ' ', sizeof(inquiry_rsp.vendor_id));
-      memset(inquiry_rsp.product_id , ' ', sizeof(inquiry_rsp.product_id));
-      memset(inquiry_rsp.product_rev, ' ', sizeof(inquiry_rsp.product_rev));
-
-      tud_msc_inquiry_cb(lun, inquiry_rsp.vendor_id, inquiry_rsp.product_id, inquiry_rsp.product_rev);
-
-      resplen = sizeof(inquiry_rsp);
-      memcpy(buffer, &inquiry_rsp, resplen);
-    }
-    break;
-
-    case SCSI_CMD_MODE_SENSE_6:
-    {
-      scsi_mode_sense6_resp_t mode_resp =
-      {
-          .data_len = 3,
-          .medium_type = 0,
-          .write_protected = false,
-          .reserved = 0,
-          .block_descriptor_len = 0  // no block descriptor are included
-      };
-
-      bool writable = true;
-      if (tud_msc_is_writable_cb) {
-          writable = tud_msc_is_writable_cb(lun);
-      }
-      mode_resp.write_protected = !writable;
-
-      resplen = sizeof(mode_resp);
-      memcpy(buffer, &mode_resp, resplen);
-    }
-    break;
-
-    case SCSI_CMD_REQUEST_SENSE:
-    {
-      scsi_sense_fixed_resp_t sense_rsp =
-      {
-          .response_code = 0x70,
-          .valid         = 1
-      };
-
-      sense_rsp.add_sense_len = sizeof(scsi_sense_fixed_resp_t) - 8;
-
-      sense_rsp.sense_key           = _mscd_itf.sense_key;
-      sense_rsp.add_sense_code      = _mscd_itf.add_sense_code;
-      sense_rsp.add_sense_qualifier = _mscd_itf.add_sense_qualifier;
-
-      resplen = sizeof(sense_rsp);
-      memcpy(buffer, &sense_rsp, resplen);
-
-      // Clear sense data after copy
-      tud_msc_set_sense(lun, 0, 0, 0);
-    }
-    break;
-
-    default: resplen = -1; break;
-  }
-
-  return resplen;
-}
-
 bool mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes)
 {
   mscd_interface_t* p_msc = &_mscd_itf;
@@ -407,8 +236,8 @@ bool mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t
       TU_ASSERT( event == XFER_RESULT_SUCCESS &&
                  xferred_bytes == sizeof(msc_cbw_t) && p_cbw->signature == MSC_CBW_SIGNATURE );
 
-      TU_LOG2("  SCSI Command: %s\n", lookup_find(&_msc_scsi_cmd_table, p_cbw->command[0]));
-      // TU_LOG2_MEM(p_cbw, xferred_bytes, 2);
+      TU_LOG(MSC_DEBUG, "  SCSI Command: %s\r\n", tu_lookup_find(&_msc_scsi_cmd_table, p_cbw->command[0]));
+      // TU_LOG_MEM(MSC_DEBUG, p_cbw, xferred_bytes, 2);
 
       p_csw->signature    = MSC_CSW_SIGNATURE;
       p_csw->tag          = p_cbw->tag;
@@ -480,8 +309,8 @@ bool mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t
     break;
 
     case MSC_STAGE_DATA:
-      TU_LOG2("  SCSI Data\n");
-      //TU_LOG2_MEM(_mscd_buf, xferred_bytes, 2);
+      TU_LOG(MSC_DEBUG, "  SCSI Data\r\n");
+      //TU_LOG_MEM(MSC_DEBUG, _mscd_buf, xferred_bytes, 2);
 
       // OUT transfer, invoke callback if needed
       if ( !tu_bit_test(p_cbw->dir, 7) )
@@ -553,7 +382,7 @@ bool mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t
       else
       {
         // READ10 & WRITE10 Can be executed with large bulk of data e.g write 8K bytes (several flash write)
-        // We break it into multiple smaller command whose data size is up to CFG_TUD_MSC_BUFSIZE
+        // We break it into multiple smaller command whose data size is up to CFG_TUD_MSC_EP_BUFSIZE
         if (SCSI_CMD_READ_10 == p_cbw->command[0])
         {
           proc_read10_cmd(rhport, p_msc);
@@ -577,8 +406,26 @@ bool mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t
       // Wait for the Status phase to complete
       if( (ep_addr == p_msc->ep_in) && (xferred_bytes == sizeof(msc_csw_t)) )
       {
-        TU_LOG2("  SCSI Status: %u\n", p_csw->status);
-        // TU_LOG2_MEM(p_csw, xferred_bytes, 2);
+        TU_LOG(MSC_DEBUG, "  SCSI Status: %u\r\n", p_csw->status);
+        // TU_LOG_MEM(MSC_DEBUG, p_csw, xferred_bytes, 2);
+
+        // Invoke complete callback if defined
+        // Note: There is racing issue with samd51 + qspi flash testing with arduino
+        // if complete_cb() is invoked after queuing the status.
+        switch(p_cbw->command[0])
+        {
+          case SCSI_CMD_READ_10:
+            if ( tud_msc_read10_complete_cb ) tud_msc_read10_complete_cb(p_cbw->lun);
+          break;
+
+          case SCSI_CMD_WRITE_10:
+            if ( tud_msc_write10_complete_cb ) tud_msc_write10_complete_cb(p_cbw->lun);
+          break;
+
+          default:
+            if ( tud_msc_scsi_complete_cb ) tud_msc_scsi_complete_cb(p_cbw->lun, p_cbw->command);
+          break;
+        }
 
         // Move to default CMD stage
         p_msc->stage = MSC_STAGE_CMD;
@@ -603,22 +450,6 @@ bool mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t
     }
     else
     {
-      // Invoke complete callback if defined
-      switch(p_cbw->command[0])
-      {
-        case SCSI_CMD_READ_10:
-          if ( tud_msc_read10_complete_cb ) tud_msc_read10_complete_cb(p_cbw->lun);
-        break;
-
-        case SCSI_CMD_WRITE_10:
-          if ( tud_msc_write10_complete_cb ) tud_msc_write10_complete_cb(p_cbw->lun);
-        break;
-
-        default:
-          if ( tud_msc_scsi_complete_cb ) tud_msc_scsi_complete_cb(p_cbw->lun, p_cbw->command);
-        break;
-      }
-
       // Move to Status Sent stage
       p_msc->stage = MSC_STAGE_STATUS_SENT;
 
@@ -633,6 +464,180 @@ bool mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t
 /*------------------------------------------------------------------*/
 /* SCSI Command Process
  *------------------------------------------------------------------*/
+
+// return response's length (copied to buffer). Negative if it is not an built-in command or indicate Failed status (CSW)
+// In case of a failed status, sense key must be set for reason of failure
+static int32_t proc_builtin_scsi(uint8_t lun, uint8_t const scsi_cmd[16], uint8_t* buffer, uint32_t bufsize)
+{
+  (void) bufsize; // TODO refractor later
+  int32_t resplen;
+
+  switch ( scsi_cmd[0] )
+  {
+    case SCSI_CMD_TEST_UNIT_READY:
+      resplen = 0;
+      if ( !tud_msc_test_unit_ready_cb(lun) )
+      {
+        // Failed status response
+        resplen = - 1;
+
+        // If sense key is not set by callback, default to Logical Unit Not Ready, Cause Not Reportable
+        if ( _mscd_itf.sense_key == 0 ) tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x04, 0x00);
+      }
+    break;
+
+    case SCSI_CMD_START_STOP_UNIT:
+      resplen = 0;
+
+      if (tud_msc_start_stop_cb)
+      {
+        scsi_start_stop_unit_t const * start_stop = (scsi_start_stop_unit_t const *) scsi_cmd;
+        if ( !tud_msc_start_stop_cb(lun, start_stop->power_condition, start_stop->start, start_stop->load_eject) )
+        {
+          // Failed status response
+          resplen = - 1;
+
+          // If sense key is not set by callback, default to Logical Unit Not Ready, Cause Not Reportable
+          if ( _mscd_itf.sense_key == 0 ) tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x04, 0x00);
+        }
+      }
+    break;
+
+    case SCSI_CMD_READ_CAPACITY_10:
+    {
+      uint32_t block_count;
+      uint32_t block_size;
+      uint16_t block_size_u16;
+
+      tud_msc_capacity_cb(lun, &block_count, &block_size_u16);
+      block_size = (uint32_t) block_size_u16;
+
+      // Invalid block size/count from callback, possibly unit is not ready
+      // stall this request, set sense key to NOT READY
+      if (block_count == 0 || block_size == 0)
+      {
+        resplen = -1;
+
+        // If sense key is not set by callback, default to Logical Unit Not Ready, Cause Not Reportable
+        if ( _mscd_itf.sense_key == 0 ) tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x04, 0x00);
+      }else
+      {
+        scsi_read_capacity10_resp_t read_capa10;
+
+        read_capa10.last_lba = tu_htonl(block_count-1);
+        read_capa10.block_size = tu_htonl(block_size);
+
+        resplen = sizeof(read_capa10);
+        memcpy(buffer, &read_capa10, resplen);
+      }
+    }
+    break;
+
+    case SCSI_CMD_READ_FORMAT_CAPACITY:
+    {
+      scsi_read_format_capacity_data_t read_fmt_capa =
+      {
+          .list_length     = 8,
+          .block_num       = 0,
+          .descriptor_type = 2, // formatted media
+          .block_size_u16  = 0
+      };
+
+      uint32_t block_count;
+      uint16_t block_size;
+
+      tud_msc_capacity_cb(lun, &block_count, &block_size);
+
+      // Invalid block size/count from callback, possibly unit is not ready
+      // stall this request, set sense key to NOT READY
+      if (block_count == 0 || block_size == 0)
+      {
+        resplen = -1;
+
+        // If sense key is not set by callback, default to Logical Unit Not Ready, Cause Not Reportable
+        if ( _mscd_itf.sense_key == 0 ) tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x04, 0x00);
+      }else
+      {
+        read_fmt_capa.block_num = tu_htonl(block_count);
+        read_fmt_capa.block_size_u16 = tu_htons(block_size);
+
+        resplen = sizeof(read_fmt_capa);
+        memcpy(buffer, &read_fmt_capa, resplen);
+      }
+    }
+    break;
+
+    case SCSI_CMD_INQUIRY:
+    {
+      scsi_inquiry_resp_t inquiry_rsp =
+      {
+          .is_removable         = 1,
+          .version              = 2,
+          .response_data_format = 2,
+      };
+
+      // vendor_id, product_id, product_rev is space padded string
+      memset(inquiry_rsp.vendor_id  , ' ', sizeof(inquiry_rsp.vendor_id));
+      memset(inquiry_rsp.product_id , ' ', sizeof(inquiry_rsp.product_id));
+      memset(inquiry_rsp.product_rev, ' ', sizeof(inquiry_rsp.product_rev));
+
+      tud_msc_inquiry_cb(lun, inquiry_rsp.vendor_id, inquiry_rsp.product_id, inquiry_rsp.product_rev);
+
+      resplen = sizeof(inquiry_rsp);
+      memcpy(buffer, &inquiry_rsp, resplen);
+    }
+    break;
+
+    case SCSI_CMD_MODE_SENSE_6:
+    {
+      scsi_mode_sense6_resp_t mode_resp =
+      {
+          .data_len = 3,
+          .medium_type = 0,
+          .write_protected = false,
+          .reserved = 0,
+          .block_descriptor_len = 0  // no block descriptor are included
+      };
+
+      bool writable = true;
+      if (tud_msc_is_writable_cb) {
+          writable = tud_msc_is_writable_cb(lun);
+      }
+      mode_resp.write_protected = !writable;
+
+      resplen = sizeof(mode_resp);
+      memcpy(buffer, &mode_resp, resplen);
+    }
+    break;
+
+    case SCSI_CMD_REQUEST_SENSE:
+    {
+      scsi_sense_fixed_resp_t sense_rsp =
+      {
+          .response_code = 0x70,
+          .valid         = 1
+      };
+
+      sense_rsp.add_sense_len = sizeof(scsi_sense_fixed_resp_t) - 8;
+
+      sense_rsp.sense_key           = _mscd_itf.sense_key;
+      sense_rsp.add_sense_code      = _mscd_itf.add_sense_code;
+      sense_rsp.add_sense_qualifier = _mscd_itf.add_sense_qualifier;
+
+      resplen = sizeof(sense_rsp);
+      memcpy(buffer, &sense_rsp, resplen);
+
+      // Clear sense data after copy
+      tud_msc_set_sense(lun, 0, 0, 0);
+    }
+    break;
+
+    default: resplen = -1; break;
+  }
+
+  return resplen;
+}
+
 static void proc_read10_cmd(uint8_t rhport, mscd_interface_t* p_msc)
 {
   msc_cbw_t const * p_cbw = &p_msc->cbw;
diff --git a/src/class/msc/msc_device.h b/src/class/msc/msc_device.h
index 66180777e..8f90ef4ad 100644
--- a/src/class/msc/msc_device.h
+++ b/src/class/msc/msc_device.h
@@ -28,7 +28,6 @@
 #define _TUSB_MSC_DEVICE_H_
 
 #include "common/tusb_common.h"
-#include "device/usbd.h"
 #include "msc.h"
 
 #ifdef __cplusplus
@@ -38,59 +37,58 @@
 //--------------------------------------------------------------------+
 // Class Driver Configuration
 //--------------------------------------------------------------------+
-TU_VERIFY_STATIC(CFG_TUD_MSC_BUFSIZE < UINT16_MAX, "Size is not correct");
 
-#ifndef CFG_TUD_MSC_BUFSIZE
-  #error CFG_TUD_MSC_BUFSIZE must be defined, value of a block size should work well, the more the better
+#if !defined(CFG_TUD_MSC_EP_BUFSIZE) & defined(CFG_TUD_MSC_BUFSIZE)
+  // TODO warn user to use new name later on
+  // #warning CFG_TUD_MSC_BUFSIZE is renamed to CFG_TUD_MSC_EP_BUFSIZE, please update to use the new name
+  #define CFG_TUD_MSC_EP_BUFSIZE  CFG_TUD_MSC_BUFSIZE
 #endif
 
-/** \addtogroup ClassDriver_MSC
- *  @{
- * \defgroup MSC_Device Device
- *  @{ */
+#ifndef CFG_TUD_MSC_EP_BUFSIZE
+  #error CFG_TUD_MSC_EP_BUFSIZE must be defined, value of a block size should work well, the more the better
+#endif
+
+TU_VERIFY_STATIC(CFG_TUD_MSC_EP_BUFSIZE < UINT16_MAX, "Size is not correct");
+
+//--------------------------------------------------------------------+
+// Application API
+//--------------------------------------------------------------------+
 
+// Set SCSI sense response
 bool tud_msc_set_sense(uint8_t lun, uint8_t sense_key, uint8_t add_sense_code, uint8_t add_sense_qualifier);
 
 //--------------------------------------------------------------------+
 // Application Callbacks (WEAK is optional)
 //--------------------------------------------------------------------+
 
-/**
- * Invoked when received \ref SCSI_CMD_READ_10 command
- * \param[in]   lun         Logical unit number
- * \param[in]   lba         Logical Block Address to be read
- * \param[in]   offset      Byte offset from LBA
- * \param[out]  buffer      Buffer which application need to update with the response data.
- * \param[in]   bufsize     Requested bytes
- *
- * \return      Number of byte read, if it is less than requested bytes by \a \b bufsize. Tinyusb will transfer
- *              this amount first and invoked this again for remaining data.
- *
- * \retval      zero        Indicate application is not ready yet to response e.g disk I/O is not complete.
- *                          tinyusb will invoke this callback with the same parameters again some time later.
- *
- * \retval      negative    Indicate error e.g reading disk I/O. tinyusb will \b STALL the corresponding
- *                          endpoint and return failed status in command status wrapper phase.
- */
+// Invoked when received SCSI READ10 command
+// - Address = lba * BLOCK_SIZE + offset
+//   - offset is only needed if CFG_TUD_MSC_EP_BUFSIZE is smaller than BLOCK_SIZE.
+//
+// - Application fill the buffer (up to bufsize) with address contents and return number of read byte. If
+//   - read < bufsize : These bytes are transferred first and callback invoked again for remaining data.
+//
+//   - read == 0      : Indicate application is not ready yet e.g disk I/O busy.
+//                      Callback invoked again with the same parameters later on.
+//
+//   - read < 0       : Indicate application error e.g invalid address. This request will be STALLed
+//                      and return failed status in command status wrapper phase.
 int32_t tud_msc_read10_cb (uint8_t lun, uint32_t lba, uint32_t offset, void* buffer, uint32_t bufsize);
 
-/**
- * Invoked when received \ref SCSI_CMD_WRITE_10 command
- * \param[in]   lun         Logical unit number
- * \param[in]   lba         Logical Block Address to be write
- * \param[in]   offset      Byte offset from LBA
- * \param[out]  buffer      Buffer which holds written data.
- * \param[in]   bufsize     Requested bytes
- *
- * \return      Number of byte written, if it is less than requested bytes by \a \b bufsize. Tinyusb will proceed with
- *              other work and invoked this again with adjusted parameters.
- *
- * \retval      zero        Indicate application is not ready yet e.g disk I/O is not complete.
- *                          Tinyusb will invoke this callback with the same parameters again some time later.
- *
- * \retval      negative    Indicate error writing disk I/O. Tinyusb will \b STALL the corresponding
- *                          endpoint and return failed status in command status wrapper phase.
- */
+// Invoked when received SCSI WRITE10 command
+// - Address = lba * BLOCK_SIZE + offset
+//   - offset is only needed if CFG_TUD_MSC_EP_BUFSIZE is smaller than BLOCK_SIZE.
+//
+// - Application write data from buffer to address contents (up to bufsize) and return number of written byte. If
+//   - write < bufsize : callback invoked again with remaining data later on.
+//
+//   - write == 0      : Indicate application is not ready yet e.g disk I/O busy.
+//                       Callback invoked again with the same parameters later on.
+//
+//   - write < 0       : Indicate application error e.g invalid address. This request will be STALLed
+//                       and return failed status in command status wrapper phase.
+//
+// TODO change buffer to const uint8_t*
 int32_t tud_msc_write10_cb (uint8_t lun, uint32_t lba, uint32_t offset, uint8_t* buffer, uint32_t bufsize);
 
 // Invoked when received SCSI_CMD_INQUIRY
@@ -145,18 +143,14 @@ TU_ATTR_WEAK void tud_msc_scsi_complete_cb(uint8_t lun, uint8_t const scsi_cmd[1
 // Hook to make a mass storage device read-only. TODO remove
 TU_ATTR_WEAK bool tud_msc_is_writable_cb(uint8_t lun);
 
-/** @} */
-/** @} */
-
 //--------------------------------------------------------------------+
 // Internal Class Driver API
 //--------------------------------------------------------------------+
-void mscd_init             (void);
-void mscd_reset            (uint8_t rhport);
-bool mscd_open             (uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t *p_length);
-bool mscd_control_request  (uint8_t rhport, tusb_control_request_t const * p_request);
-bool mscd_control_complete (uint8_t rhport, tusb_control_request_t const * p_request);
-bool mscd_xfer_cb          (uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
+void     mscd_init            (void);
+void     mscd_reset           (uint8_t rhport);
+uint16_t mscd_open            (uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t max_len);
+bool     mscd_control_xfer_cb (uint8_t rhport, uint8_t stage, tusb_control_request_t const * p_request);
+bool     mscd_xfer_cb         (uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
 
 #ifdef __cplusplus
  }
diff --git a/src/class/msc/msc_host.c b/src/class/msc/msc_host.c
index e20969f57..f02f4550a 100644
--- a/src/class/msc/msc_host.c
+++ b/src/class/msc/msc_host.c
@@ -28,272 +28,354 @@
 
 #if TUSB_OPT_HOST_ENABLED & CFG_TUH_MSC
 
-//--------------------------------------------------------------------+
-// INCLUDE
-//--------------------------------------------------------------------+
-#include "common/tusb_common.h"
+#include "host/usbh.h"
+#include "host/usbh_classdriver.h"
+
 #include "msc_host.h"
 
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF
 //--------------------------------------------------------------------+
-CFG_TUSB_MEM_SECTION static msch_interface_t msch_data[CFG_TUSB_HOST_DEVICE_MAX];
+enum
+{
+  MSC_STAGE_IDLE = 0,
+  MSC_STAGE_CMD,
+  MSC_STAGE_DATA,
+  MSC_STAGE_STATUS,
+};
 
-//------------- Initalization Data -------------//
-static osal_semaphore_def_t msch_sem_def;
-static osal_semaphore_t msch_sem_hdl;
+typedef struct
+{
+  uint8_t itf_num;
+  uint8_t ep_in;
+  uint8_t ep_out;
 
-// buffer used to read scsi information when mounted, largest response data currently is inquiry
-CFG_TUSB_MEM_SECTION TU_ATTR_ALIGNED(4) static uint8_t msch_buffer[sizeof(scsi_inquiry_resp_t)];
+  uint8_t max_lun;
 
-//--------------------------------------------------------------------+
-// INTERNAL OBJECT & FUNCTION DECLARATION
-//--------------------------------------------------------------------+
+  volatile bool configured; // Receive SET_CONFIGURE
+  volatile bool mounted;    // Enumeration is complete
+
+  struct {
+    uint32_t block_size;
+    uint32_t block_count;
+  } capacity[CFG_TUH_MSC_MAXLUN];
+
+  //------------- SCSI -------------//
+  uint8_t stage;
+  void*   buffer;
+  tuh_msc_complete_cb_t complete_cb;
+
+  msc_cbw_t cbw;
+  msc_csw_t csw;
+}msch_interface_t;
+
+CFG_TUSB_MEM_SECTION static msch_interface_t _msch_itf[CFG_TUSB_HOST_DEVICE_MAX];
+
+// buffer used to read scsi information when mounted
+// largest response data currently is inquiry TODO Inquiry is not part of enum anymore
+CFG_TUSB_MEM_SECTION TU_ATTR_ALIGNED(4)
+static uint8_t _msch_buffer[sizeof(scsi_inquiry_resp_t)];
+
+static inline msch_interface_t* get_itf(uint8_t dev_addr)
+{
+  return &_msch_itf[dev_addr-1];
+}
 
 //--------------------------------------------------------------------+
 // PUBLIC API
 //--------------------------------------------------------------------+
-bool tuh_msc_is_mounted(uint8_t dev_addr)
+uint8_t tuh_msc_get_maxlun(uint8_t dev_addr)
 {
-  return  tuh_device_is_configured(dev_addr) && // is configured can be omitted
-          msch_data[dev_addr-1].is_initialized;
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  return p_msc->max_lun;
 }
 
-bool tuh_msc_is_busy(uint8_t dev_addr)
+uint32_t tuh_msc_get_block_count(uint8_t dev_addr, uint8_t lun)
 {
-  return  msch_data[dev_addr-1].is_initialized &&
-          hcd_edpt_busy(dev_addr, msch_data[dev_addr-1].ep_in);
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  return p_msc->capacity[lun].block_count;
 }
 
-uint8_t const* tuh_msc_get_vendor_name(uint8_t dev_addr)
+uint32_t tuh_msc_get_block_size(uint8_t dev_addr, uint8_t lun)
 {
-  return msch_data[dev_addr-1].is_initialized ? msch_data[dev_addr-1].vendor_id : NULL;
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  return p_msc->capacity[lun].block_size;
 }
 
-uint8_t const* tuh_msc_get_product_name(uint8_t dev_addr)
+bool tuh_msc_mounted(uint8_t dev_addr)
 {
-  return msch_data[dev_addr-1].is_initialized ? msch_data[dev_addr-1].product_id : NULL;
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  return p_msc->mounted;
 }
 
-tusb_error_t tuh_msc_get_capacity(uint8_t dev_addr, uint32_t* p_last_lba, uint32_t* p_block_size)
+bool tuh_msc_ready(uint8_t dev_addr)
 {
-  if ( !msch_data[dev_addr-1].is_initialized )   return TUSB_ERROR_MSCH_DEVICE_NOT_MOUNTED;
-  TU_ASSERT(p_last_lba != NULL && p_block_size != NULL, TUSB_ERROR_INVALID_PARA);
-
-  (*p_last_lba)   = msch_data[dev_addr-1].last_lba;
-  (*p_block_size) = (uint32_t) msch_data[dev_addr-1].block_size;
-
-  return TUSB_ERROR_NONE;
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  return p_msc->mounted && !usbh_edpt_busy(dev_addr, p_msc->ep_in);
 }
 
 //--------------------------------------------------------------------+
 // PUBLIC API: SCSI COMMAND
 //--------------------------------------------------------------------+
-static inline void msc_cbw_add_signature(msc_cbw_t *p_cbw, uint8_t lun)
+static inline void cbw_init(msc_cbw_t *cbw, uint8_t lun)
 {
-  p_cbw->signature  = MSC_CBW_SIGNATURE;
-  p_cbw->tag        = 0xCAFECAFE;
-  p_cbw->lun        = lun;
+  tu_memclr(cbw, sizeof(msc_cbw_t));
+  cbw->signature = MSC_CBW_SIGNATURE;
+  cbw->tag       = 0x54555342; // TUSB
+  cbw->lun       = lun;
 }
 
-static tusb_error_t msch_command_xfer(uint8_t dev_addr, msch_interface_t * p_msch, void* p_buffer)
+bool tuh_msc_scsi_command(uint8_t dev_addr, msc_cbw_t const* cbw, void* data, tuh_msc_complete_cb_t complete_cb)
 {
-  if ( NULL != p_buffer)
-  { // there is data phase
-    if (p_msch->cbw.dir & TUSB_DIR_IN_MASK)
-    {
-      TU_ASSERT( hcd_pipe_xfer(dev_addr, p_msch->ep_out, (uint8_t*) &p_msch->cbw, sizeof(msc_cbw_t), false), TUSB_ERROR_FAILED );
-      TU_ASSERT( hcd_pipe_queue_xfer(dev_addr, p_msch->ep_in , p_buffer, p_msch->cbw.total_bytes), TUSB_ERROR_FAILED );
-    }else
-    {
-      TU_ASSERT( hcd_pipe_queue_xfer(dev_addr, p_msch->ep_out, (uint8_t*) &p_msch->cbw, sizeof(msc_cbw_t)), TUSB_ERROR_FAILED );
-      TU_ASSERT( hcd_pipe_xfer(dev_addr, p_msch->ep_out , p_buffer, p_msch->cbw.total_bytes, false), TUSB_ERROR_FAILED );
-    }
-  }
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  TU_VERIFY(p_msc->configured);
 
-  TU_ASSERT( hcd_pipe_xfer(dev_addr, p_msch->ep_in , (uint8_t*) &p_msch->csw, sizeof(msc_csw_t), true), TUSB_ERROR_FAILED);
+  // TODO claim endpoint
 
-  return TUSB_ERROR_NONE;
-}
+  p_msc->cbw = *cbw;
+  p_msc->stage = MSC_STAGE_CMD;
+  p_msc->buffer = data;
+  p_msc->complete_cb = complete_cb;
 
-tusb_error_t tusbh_msc_inquiry(uint8_t dev_addr, uint8_t lun, uint8_t *p_data)
-{
-  msch_interface_t* p_msch = &msch_data[dev_addr-1];
+  TU_ASSERT(usbh_edpt_xfer(dev_addr, p_msc->ep_out, (uint8_t*) &p_msc->cbw, sizeof(msc_cbw_t)));
 
-  //------------- Command Block Wrapper -------------//
-  msc_cbw_add_signature(&p_msch->cbw, lun);
-  p_msch->cbw.total_bytes = sizeof(scsi_inquiry_resp_t);
-  p_msch->cbw.dir        = TUSB_DIR_IN_MASK;
-  p_msch->cbw.cmd_len    = sizeof(scsi_inquiry_t);
+  return true;
+}
 
-  //------------- SCSI command -------------//
-  scsi_inquiry_t cmd_inquiry =
-  {
-      .cmd_code     = SCSI_CMD_INQUIRY,
-      .alloc_length = sizeof(scsi_inquiry_resp_t)
-  };
+bool tuh_msc_read_capacity(uint8_t dev_addr, uint8_t lun, scsi_read_capacity10_resp_t* response, tuh_msc_complete_cb_t complete_cb)
+{
+   msch_interface_t* p_msc = get_itf(dev_addr);
+   TU_VERIFY(p_msc->configured);
 
-  memcpy(p_msch->cbw.command, &cmd_inquiry, p_msch->cbw.cmd_len);
+  msc_cbw_t cbw;
+  cbw_init(&cbw, lun);
 
-  TU_ASSERT_ERR ( msch_command_xfer(dev_addr, p_msch, p_data) );
+  cbw.total_bytes = sizeof(scsi_read_capacity10_resp_t);
+  cbw.dir        = TUSB_DIR_IN_MASK;
+  cbw.cmd_len    = sizeof(scsi_read_capacity10_t);
+  cbw.command[0] = SCSI_CMD_READ_CAPACITY_10;
 
-  return TUSB_ERROR_NONE;
+  return tuh_msc_scsi_command(dev_addr, &cbw, response, complete_cb);
 }
 
-tusb_error_t tusbh_msc_read_capacity10(uint8_t dev_addr, uint8_t lun, uint8_t *p_data)
+bool tuh_msc_inquiry(uint8_t dev_addr, uint8_t lun, scsi_inquiry_resp_t* response, tuh_msc_complete_cb_t complete_cb)
 {
-  msch_interface_t* p_msch = &msch_data[dev_addr-1];
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  TU_VERIFY(p_msc->mounted);
 
-  //------------- Command Block Wrapper -------------//
-  msc_cbw_add_signature(&p_msch->cbw, lun);
-  p_msch->cbw.total_bytes = sizeof(scsi_read_capacity10_resp_t);
-  p_msch->cbw.dir        = TUSB_DIR_IN_MASK;
-  p_msch->cbw.cmd_len    = sizeof(scsi_read_capacity10_t);
+  msc_cbw_t cbw;
+  cbw_init(&cbw, lun);
 
-  //------------- SCSI command -------------//
-  scsi_read_capacity10_t cmd_read_capacity10 =
+  cbw.total_bytes = sizeof(scsi_inquiry_resp_t);
+  cbw.dir         = TUSB_DIR_IN_MASK;
+  cbw.cmd_len     = sizeof(scsi_inquiry_t);
+
+  scsi_inquiry_t const cmd_inquiry =
   {
-      .cmd_code                 = SCSI_CMD_READ_CAPACITY_10,
-      .lba                      = 0,
-      .partial_medium_indicator = 0
+    .cmd_code     = SCSI_CMD_INQUIRY,
+    .alloc_length = sizeof(scsi_inquiry_resp_t)
   };
+  memcpy(cbw.command, &cmd_inquiry, cbw.cmd_len);
+
+  return tuh_msc_scsi_command(dev_addr, &cbw, response, complete_cb);
+}
+
+bool tuh_msc_test_unit_ready(uint8_t dev_addr, uint8_t lun, tuh_msc_complete_cb_t complete_cb)
+{
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  TU_VERIFY(p_msc->configured);
 
-  memcpy(p_msch->cbw.command, &cmd_read_capacity10, p_msch->cbw.cmd_len);
+  msc_cbw_t cbw;
+  cbw_init(&cbw, lun);
 
-  TU_ASSERT_ERR ( msch_command_xfer(dev_addr, p_msch, p_data) );
+  cbw.total_bytes = 0;
+  cbw.dir         = TUSB_DIR_OUT;
+  cbw.cmd_len     = sizeof(scsi_test_unit_ready_t);
+  cbw.command[0]  = SCSI_CMD_TEST_UNIT_READY;
+  cbw.command[1]  = lun; // according to wiki TODO need verification
 
-  return TUSB_ERROR_NONE;
+  return tuh_msc_scsi_command(dev_addr, &cbw, NULL, complete_cb);
 }
 
-tusb_error_t tuh_msc_request_sense(uint8_t dev_addr, uint8_t lun, uint8_t *p_data)
+bool tuh_msc_request_sense(uint8_t dev_addr, uint8_t lun, void *resposne, tuh_msc_complete_cb_t complete_cb)
 {
-  (void) lun; // TODO [MSCH] multiple lun support
+  msc_cbw_t cbw;
+  cbw_init(&cbw, lun);
 
-  msch_interface_t* p_msch = &msch_data[dev_addr-1];
+  cbw.total_bytes = 18; // TODO sense response
+  cbw.dir         = TUSB_DIR_IN_MASK;
+  cbw.cmd_len     = sizeof(scsi_request_sense_t);
 
-  //------------- Command Block Wrapper -------------//
-  p_msch->cbw.total_bytes = 18;
-  p_msch->cbw.dir        = TUSB_DIR_IN_MASK;
-  p_msch->cbw.cmd_len    = sizeof(scsi_request_sense_t);
-
-  //------------- SCSI command -------------//
-  scsi_request_sense_t cmd_request_sense =
+  scsi_request_sense_t const cmd_request_sense =
   {
-      .cmd_code     = SCSI_CMD_REQUEST_SENSE,
-      .alloc_length = 18
+    .cmd_code     = SCSI_CMD_REQUEST_SENSE,
+    .alloc_length = 18
   };
 
-  memcpy(p_msch->cbw.command, &cmd_request_sense, p_msch->cbw.cmd_len);
-
-  TU_ASSERT_ERR ( msch_command_xfer(dev_addr, p_msch, p_data) );
+  memcpy(cbw.command, &cmd_request_sense, cbw.cmd_len);
 
-  return TUSB_ERROR_NONE;
+  return tuh_msc_scsi_command(dev_addr, &cbw, resposne, complete_cb);
 }
 
-tusb_error_t tuh_msc_test_unit_ready(uint8_t dev_addr, uint8_t lun,  msc_csw_t * p_csw)
+bool tuh_msc_read10(uint8_t dev_addr, uint8_t lun, void * buffer, uint32_t lba, uint16_t block_count, tuh_msc_complete_cb_t complete_cb)
+{
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  TU_VERIFY(p_msc->mounted);
+
+  msc_cbw_t cbw;
+  cbw_init(&cbw, lun);
+ 
+  cbw.total_bytes = block_count*p_msc->capacity[lun].block_size;
+  cbw.dir         = TUSB_DIR_IN_MASK;
+  cbw.cmd_len     = sizeof(scsi_read10_t);
+ 
+  scsi_read10_t const cmd_read10 =
+  {
+    .cmd_code    = SCSI_CMD_READ_10,
+    .lba         = tu_htonl(lba),
+    .block_count = tu_htons(block_count)
+  };
+ 
+  memcpy(cbw.command, &cmd_read10, cbw.cmd_len);
+ 
+  return tuh_msc_scsi_command(dev_addr, &cbw, buffer, complete_cb);
+}
+ 
+bool tuh_msc_write10(uint8_t dev_addr, uint8_t lun, void const * buffer, uint32_t lba, uint16_t block_count, tuh_msc_complete_cb_t complete_cb)
 {
-  msch_interface_t* p_msch = &msch_data[dev_addr-1];
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  TU_VERIFY(p_msc->mounted);
 
-  //------------- Command Block Wrapper -------------//
-  msc_cbw_add_signature(&p_msch->cbw, lun);
+  msc_cbw_t cbw;
+  cbw_init(&cbw, lun);
 
-  p_msch->cbw.total_bytes = 0; // Number of bytes
-  p_msch->cbw.dir        = TUSB_DIR_OUT;
-  p_msch->cbw.cmd_len    = sizeof(scsi_test_unit_ready_t);
+  cbw.total_bytes = block_count*p_msc->capacity[lun].block_size;
+  cbw.dir         = TUSB_DIR_OUT;
+  cbw.cmd_len     = sizeof(scsi_write10_t);
 
-  //------------- SCSI command -------------//
-  scsi_test_unit_ready_t cmd_test_unit_ready =
+  scsi_write10_t const cmd_write10 =
   {
-      .cmd_code = SCSI_CMD_TEST_UNIT_READY,
-      .lun      = lun // according to wiki
+    .cmd_code    = SCSI_CMD_WRITE_10,
+    .lba         = tu_htonl(lba),
+    .block_count = tu_htons(block_count)
   };
 
-  memcpy(p_msch->cbw.command, &cmd_test_unit_ready, p_msch->cbw.cmd_len);
-
-  // TODO MSCH refractor test uinit ready
-  TU_ASSERT( hcd_pipe_xfer(dev_addr, p_msch->ep_out, (uint8_t*) &p_msch->cbw, sizeof(msc_cbw_t), false), TUSB_ERROR_FAILED );
-  TU_ASSERT( hcd_pipe_xfer(dev_addr, p_msch->ep_in , (uint8_t*) p_csw, sizeof(msc_csw_t), true), TUSB_ERROR_FAILED );
+  memcpy(cbw.command, &cmd_write10, cbw.cmd_len);
 
-  return TUSB_ERROR_NONE;
+  return tuh_msc_scsi_command(dev_addr, &cbw, (void*) buffer, complete_cb);
 }
 
-tusb_error_t  tuh_msc_read10(uint8_t dev_addr, uint8_t lun, void * p_buffer, uint32_t lba, uint16_t block_count)
+#if 0
+// MSC interface Reset (not used now)
+bool tuh_msc_reset(uint8_t dev_addr)
 {
-  msch_interface_t* p_msch = &msch_data[dev_addr-1];
-
-  //------------- Command Block Wrapper -------------//
-  msc_cbw_add_signature(&p_msch->cbw, lun);
-
-  p_msch->cbw.total_bytes = p_msch->block_size*block_count; // Number of bytes
-  p_msch->cbw.dir        = TUSB_DIR_IN_MASK;
-  p_msch->cbw.cmd_len    = sizeof(scsi_read10_t);
-
-  //------------- SCSI command -------------//
-  scsi_read10_t cmd_read10 =
+  tusb_control_request_t const new_request =
   {
-      .cmd_code    = SCSI_CMD_READ_10,
-      .lba         = tu_htonl(lba),
-      .block_count = tu_htons(block_count)
+    .bmRequestType_bit =
+    {
+      .recipient = TUSB_REQ_RCPT_INTERFACE,
+      .type      = TUSB_REQ_TYPE_CLASS,
+      .direction = TUSB_DIR_OUT
+    },
+    .bRequest = MSC_REQ_RESET,
+    .wValue   = 0,
+    .wIndex   = p_msc->itf_num,
+    .wLength  = 0
   };
+  TU_ASSERT( usbh_control_xfer( dev_addr, &new_request, NULL ) );
+}
+#endif
+
+//--------------------------------------------------------------------+
+// CLASS-USBH API
+//--------------------------------------------------------------------+
+void msch_init(void)
+{
+  tu_memclr(_msch_itf, sizeof(msch_interface_t)*CFG_TUSB_HOST_DEVICE_MAX);
+}
 
-  memcpy(p_msch->cbw.command, &cmd_read10, p_msch->cbw.cmd_len);
+void msch_close(uint8_t dev_addr)
+{
+  msch_interface_t* p_msc = get_itf(dev_addr);
 
-  TU_ASSERT_ERR ( msch_command_xfer(dev_addr, p_msch, p_buffer));
+  // invoke Application Callback
+  if (p_msc->mounted && tuh_msc_umount_cb) tuh_msc_umount_cb(dev_addr);
 
-  return TUSB_ERROR_NONE;
+  tu_memclr(p_msc, sizeof(msch_interface_t));
 }
 
-tusb_error_t tuh_msc_write10(uint8_t dev_addr, uint8_t lun, void const * p_buffer, uint32_t lba, uint16_t block_count)
+bool msch_xfer_cb(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes)
 {
-  msch_interface_t* p_msch = &msch_data[dev_addr-1];
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  msc_cbw_t const * cbw = &p_msc->cbw;
+  msc_csw_t       * csw = &p_msc->csw;
 
-  //------------- Command Block Wrapper -------------//
-  msc_cbw_add_signature(&p_msch->cbw, lun);
+  switch (p_msc->stage)
+  {
+    case MSC_STAGE_CMD:
+      // Must be Command Block
+      TU_ASSERT(ep_addr == p_msc->ep_out &&  event == XFER_RESULT_SUCCESS && xferred_bytes == sizeof(msc_cbw_t));
 
-  p_msch->cbw.total_bytes = p_msch->block_size*block_count; // Number of bytes
-  p_msch->cbw.dir        = TUSB_DIR_OUT;
-  p_msch->cbw.cmd_len    = sizeof(scsi_write10_t);
+      if ( cbw->total_bytes && p_msc->buffer )
+      {
+        // Data stage if any
+        p_msc->stage = MSC_STAGE_DATA;
 
-  //------------- SCSI command -------------//
-  scsi_write10_t cmd_write10 =
-  {
-      .cmd_code    = SCSI_CMD_WRITE_10,
-      .lba         = tu_htonl(lba),
-      .block_count = tu_htons(block_count)
-  };
+        uint8_t const ep_data = (cbw->dir & TUSB_DIR_IN_MASK) ? p_msc->ep_in : p_msc->ep_out;
+        TU_ASSERT(usbh_edpt_xfer(dev_addr, ep_data, p_msc->buffer, cbw->total_bytes));
+      }else
+      {
+        // Status stage
+        p_msc->stage = MSC_STAGE_STATUS;
+        TU_ASSERT(usbh_edpt_xfer(dev_addr, p_msc->ep_in, (uint8_t*) &p_msc->csw, sizeof(msc_csw_t)));
+      }
+    break;
 
-  memcpy(p_msch->cbw.command, &cmd_write10, p_msch->cbw.cmd_len);
+    case MSC_STAGE_DATA:
+      // Status stage
+      p_msc->stage = MSC_STAGE_STATUS;
+      TU_ASSERT(usbh_edpt_xfer(dev_addr, p_msc->ep_in, (uint8_t*) &p_msc->csw, sizeof(msc_csw_t)));
+    break;
 
-  TU_ASSERT_ERR ( msch_command_xfer(dev_addr, p_msch, (void*) p_buffer));
+    case MSC_STAGE_STATUS:
+      // SCSI op is complete
+      p_msc->stage = MSC_STAGE_IDLE;
 
-  return TUSB_ERROR_NONE;
+      if (p_msc->complete_cb) p_msc->complete_cb(dev_addr, cbw, csw);
+    break;
+
+    // unknown state
+    default: break;
+  }
+
+  return true;
 }
 
 //--------------------------------------------------------------------+
-// CLASS-USBH API (don't require to verify parameters)
+// MSC Enumeration
 //--------------------------------------------------------------------+
-void msch_init(void)
-{
-  tu_memclr(msch_data, sizeof(msch_interface_t)*CFG_TUSB_HOST_DEVICE_MAX);
-  msch_sem_hdl = osal_semaphore_create(&msch_sem_def);
-}
 
-bool msch_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t *p_length)
+static bool config_get_maxlun_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
+static bool config_test_unit_ready_complete(uint8_t dev_addr, msc_cbw_t const* cbw, msc_csw_t const* csw);
+static bool config_request_sense_complete(uint8_t dev_addr, msc_cbw_t const* cbw, msc_csw_t const* csw);
+static bool config_read_capacity_complete(uint8_t dev_addr, msc_cbw_t const* cbw, msc_csw_t const* csw);
+
+bool msch_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *desc_itf, uint16_t max_len)
 {
-  TU_VERIFY (MSC_SUBCLASS_SCSI == itf_desc->bInterfaceSubClass &&
-             MSC_PROTOCOL_BOT  == itf_desc->bInterfaceProtocol);
+  TU_VERIFY (MSC_SUBCLASS_SCSI == desc_itf->bInterfaceSubClass &&
+             MSC_PROTOCOL_BOT  == desc_itf->bInterfaceProtocol);
 
-  msch_interface_t* p_msc = &msch_data[dev_addr-1];
+  // msc driver length is fixed
+  uint16_t const drv_len = sizeof(tusb_desc_interface_t) + desc_itf->bNumEndpoints*sizeof(tusb_desc_endpoint_t);
+  TU_ASSERT(drv_len <= max_len);
 
-  //------------- Open Data Pipe -------------//
-  tusb_desc_endpoint_t const * ep_desc = (tusb_desc_endpoint_t const *) tu_desc_next(itf_desc);
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  tusb_desc_endpoint_t const * ep_desc = (tusb_desc_endpoint_t const *) tu_desc_next(desc_itf);
 
   for(uint32_t i=0; i<2; i++)
   {
-    TU_ASSERT(TUSB_DESC_ENDPOINT == ep_desc->bDescriptorType);
-    TU_ASSERT(TUSB_XFER_BULK == ep_desc->bmAttributes.xfer);
-
-    TU_ASSERT(hcd_edpt_open(rhport, dev_addr, ep_desc));
+    TU_ASSERT(TUSB_DESC_ENDPOINT == ep_desc->bDescriptorType && TUSB_XFER_BULK == ep_desc->bmAttributes.xfer);
+    TU_ASSERT(usbh_edpt_open(rhport, dev_addr, ep_desc));
 
     if ( tu_edpt_dir(ep_desc->bEndpointAddress) == TUSB_DIR_IN )
     {
@@ -306,108 +388,101 @@ bool msch_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *it
     ep_desc = (tusb_desc_endpoint_t const *) tu_desc_next(ep_desc);
   }
 
-  p_msc->itf_numr = itf_desc->bInterfaceNumber;
-  (*p_length) += sizeof(tusb_desc_interface_t) + 2*sizeof(tusb_desc_endpoint_t);
+  p_msc->itf_num = desc_itf->bInterfaceNumber;
 
-  //------------- Get Max Lun -------------//
-  tusb_control_request_t request = {
-        .bmRequestType_bit = { .recipient = TUSB_REQ_RCPT_INTERFACE, .type = TUSB_REQ_TYPE_CLASS, .direction = TUSB_DIR_IN },
-        .bRequest = MSC_REQ_GET_MAX_LUN,
-        .wValue = 0,
-        .wIndex = p_msc->itf_numr,
-        .wLength = 1
-  };
-  // TODO STALL means zero
-  TU_ASSERT( usbh_control_xfer( dev_addr, &request, msch_buffer ) );
-  p_msc->max_lun = msch_buffer[0];
-
-#if 0
-  //------------- Reset -------------//
-  request = (tusb_control_request_t) {
-        .bmRequestType_bit = { .recipient = TUSB_REQ_RCPT_INTERFACE, .type = TUSB_REQ_TYPE_CLASS, .direction = TUSB_DIR_OUT },
-        .bRequest = MSC_REQ_RESET,
-        .wValue = 0,
-        .wIndex = p_msc->itf_numr,
-        .wLength = 0
-  };
-  TU_ASSERT( usbh_control_xfer( dev_addr, &request, NULL ) );
-#endif
-
-  enum { SCSI_XFER_TIMEOUT = 2000 };
-  //------------- SCSI Inquiry -------------//
-  tusbh_msc_inquiry(dev_addr, 0, msch_buffer);
-  TU_ASSERT( osal_semaphore_wait(msch_sem_hdl, SCSI_XFER_TIMEOUT) );
+  return true;
+}
 
-  memcpy(p_msc->vendor_id , ((scsi_inquiry_resp_t*) msch_buffer)->vendor_id , 8);
-  memcpy(p_msc->product_id, ((scsi_inquiry_resp_t*) msch_buffer)->product_id, 16);
+bool msch_set_config(uint8_t dev_addr, uint8_t itf_num)
+{
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  TU_ASSERT(p_msc->itf_num == itf_num);
 
-  //------------- SCSI Read Capacity 10 -------------//
-  tusbh_msc_read_capacity10(dev_addr, 0, msch_buffer);
-  TU_ASSERT( osal_semaphore_wait(msch_sem_hdl, SCSI_XFER_TIMEOUT));
+  p_msc->configured = true;
 
-  // NOTE: my toshiba thumb-drive stall the first Read Capacity and require the sequence
-  // Read Capacity --> Stalled --> Clear Stall --> Request Sense --> Read Capacity (2) to work
-  if ( hcd_edpt_stalled(dev_addr, p_msc->ep_in) )
+  //------------- Get Max Lun -------------//
+  TU_LOG2("MSC Get Max Lun\r\n");
+  tusb_control_request_t request =
   {
-    // clear stall TODO abstract clear stall function
-    request = (tusb_control_request_t) {
-      .bmRequestType_bit = { .recipient = TUSB_REQ_RCPT_ENDPOINT, .type = TUSB_REQ_TYPE_STANDARD, .direction = TUSB_DIR_OUT },
-          .bRequest = TUSB_REQ_CLEAR_FEATURE,
-          .wValue = 0,
-          .wIndex = p_msc->ep_in,
-          .wLength = 0
-    };
-
-    TU_ASSERT(usbh_control_xfer( dev_addr, &request, NULL ));
-
-    hcd_edpt_clear_stall(dev_addr, p_msc->ep_in);
-    TU_ASSERT( osal_semaphore_wait(msch_sem_hdl, SCSI_XFER_TIMEOUT) ); // wait for SCSI status
+    .bmRequestType_bit =
+    {
+      .recipient = TUSB_REQ_RCPT_INTERFACE,
+      .type      = TUSB_REQ_TYPE_CLASS,
+      .direction = TUSB_DIR_IN
+    },
+    .bRequest = MSC_REQ_GET_MAX_LUN,
+    .wValue   = 0,
+    .wIndex   = itf_num,
+    .wLength  = 1
+  };
+  TU_ASSERT(tuh_control_xfer(dev_addr, &request, &p_msc->max_lun, config_get_maxlun_complete));
 
-    //------------- SCSI Request Sense -------------//
-    (void) tuh_msc_request_sense(dev_addr, 0, msch_buffer);
-    TU_ASSERT(osal_semaphore_wait(msch_sem_hdl, SCSI_XFER_TIMEOUT));
+  return true;
+}
 
-    //------------- Re-read SCSI Read Capactity -------------//
-    tusbh_msc_read_capacity10(dev_addr, 0, msch_buffer);
-    TU_ASSERT(osal_semaphore_wait(msch_sem_hdl, SCSI_XFER_TIMEOUT));
-  }
+static bool config_get_maxlun_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
+{
+  (void) request;
 
-  p_msc->last_lba   = tu_ntohl( ((scsi_read_capacity10_resp_t*)msch_buffer)->last_lba );
-  p_msc->block_size = (uint16_t) tu_ntohl( ((scsi_read_capacity10_resp_t*)msch_buffer)->block_size );
+  msch_interface_t* p_msc = get_itf(dev_addr);
 
-  p_msc->is_initialized = true;
+  // STALL means zero
+  p_msc->max_lun = (XFER_RESULT_SUCCESS == result) ? _msch_buffer[0] : 0;
+  p_msc->max_lun++; // MAX LUN is minus 1 by specs
 
-  tuh_msc_mounted_cb(dev_addr);
+  // TODO multiple LUN support
+  TU_LOG2("SCSI Test Unit Ready\r\n");
+  uint8_t const lun = 0;
+  tuh_msc_test_unit_ready(dev_addr, lun, config_test_unit_ready_complete);
 
   return true;
 }
 
-void msch_isr(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes)
+static bool config_test_unit_ready_complete(uint8_t dev_addr, msc_cbw_t const* cbw, msc_csw_t const* csw)
 {
-  msch_interface_t* p_msc = &msch_data[dev_addr-1];
-  if ( ep_addr == p_msc->ep_in )
+  if (csw->status == 0)
   {
-    if (p_msc->is_initialized)
-    {
-      tuh_msc_isr(dev_addr, event, xferred_bytes);
-    }else
-    { // still initializing under open subtask
-      osal_semaphore_post(msch_sem_hdl, true);
-    }
+    // Unit is ready, read its capacity
+    TU_LOG2("SCSI Read Capacity\r\n");
+    tuh_msc_read_capacity(dev_addr, cbw->lun, (scsi_read_capacity10_resp_t*) ((void*) _msch_buffer), config_read_capacity_complete);
+  }else
+  {
+    // Note: During enumeration, some device fails Test Unit Ready and require a few retries
+    // with Request Sense to start working !!
+    // TODO limit number of retries
+    TU_LOG2("SCSI Request Sense\r\n");
+    TU_ASSERT(tuh_msc_request_sense(dev_addr, cbw->lun, _msch_buffer, config_request_sense_complete));
   }
+
+  return true;
 }
 
-void msch_close(uint8_t dev_addr)
+static bool config_request_sense_complete(uint8_t dev_addr, msc_cbw_t const* cbw, msc_csw_t const* csw)
 {
-  tu_memclr(&msch_data[dev_addr-1], sizeof(msch_interface_t));
-  osal_semaphore_reset(msch_sem_hdl);
-
-  tuh_msc_unmounted_cb(dev_addr); // invoke Application Callback
+  TU_ASSERT(csw->status == 0);
+  TU_ASSERT(tuh_msc_test_unit_ready(dev_addr, cbw->lun, config_test_unit_ready_complete));
+  return true;
 }
 
-//--------------------------------------------------------------------+
-// INTERNAL & HELPER
-//--------------------------------------------------------------------+
+static bool config_read_capacity_complete(uint8_t dev_addr, msc_cbw_t const* cbw, msc_csw_t const* csw)
+{
+  TU_ASSERT(csw->status == 0);
 
+  msch_interface_t* p_msc = get_itf(dev_addr);
+
+  // Capacity response field: Block size and Last LBA are both Big-Endian
+  scsi_read_capacity10_resp_t* resp = (scsi_read_capacity10_resp_t*) ((void*) _msch_buffer);
+  p_msc->capacity[cbw->lun].block_count = tu_ntohl(resp->last_lba) + 1;
+  p_msc->capacity[cbw->lun].block_size = tu_ntohl(resp->block_size);
+
+  // Mark enumeration is complete
+  p_msc->mounted = true;
+  if (tuh_msc_mount_cb) tuh_msc_mount_cb(dev_addr);
+
+  // notify usbh that driver enumeration is complete
+  usbh_driver_set_config_complete(dev_addr, p_msc->itf_num);
+
+  return true;
+}
 
 #endif
diff --git a/src/class/msc/msc_host.h b/src/class/msc/msc_host.h
index 76cf86853..7718ad4fe 100644
--- a/src/class/msc/msc_host.h
+++ b/src/class/msc/msc_host.h
@@ -27,180 +27,93 @@
 #ifndef _TUSB_MSC_HOST_H_
 #define _TUSB_MSC_HOST_H_
 
-#include "common/tusb_common.h"
-#include "host/usbh.h"
 #include "msc.h"
 
 #ifdef __cplusplus
  extern "C" {
 #endif
 
-/** \addtogroup ClassDriver_MSC
- *  @{
- * \defgroup MSC_Host Host
- *  The interface API includes status checking function, data transferring function and callback functions
- *  @{ */
 //--------------------------------------------------------------------+
-// MASS STORAGE Application API
+// Class Driver Configuration
 //--------------------------------------------------------------------+
-/** \brief      Check if device supports MassStorage interface or not
- * \param[in]   dev_addr    device address
- * \retval      true if device supports
- * \retval      false if device does not support or is not mounted
- */
-bool          tuh_msc_is_mounted(uint8_t dev_addr);
 
-/** \brief      Check if the interface is currently busy or not
- * \param[in]   dev_addr device address
- * \retval      true if the interface is busy meaning the stack is still transferring/waiting data from/to device
- * \retval      false if the interface is not busy meaning the stack successfully transferred data from/to device
- * \note        This function is used to check if previous transfer is complete (success or error), so that the next transfer
- *              can be scheduled. User needs to make sure the corresponding interface is mounted (by \ref tuh_msc_is_mounted)
- *              before calling this function
- */
-bool          tuh_msc_is_busy(uint8_t dev_addr);
+#ifndef CFG_TUH_MSC_MAXLUN
+#define CFG_TUH_MSC_MAXLUN  4
+#endif
 
-/** \brief      Get SCSI vendor's name of MassStorage device
- * \param[in]   dev_addr device address
- * \return      pointer to vendor's name or NULL if specified device does not support MassStorage
- * \note        SCSI vendor's name is 8-byte length field in \ref scsi_inquiry_data_t. During enumeration, the stack has already
- *              retrieved (via SCSI INQUIRY) and store this information internally. There is no need for application to re-send SCSI INQUIRY
- *              command or allocate buffer for this.
- */
-uint8_t const* tuh_msc_get_vendor_name(uint8_t dev_addr);
+typedef bool (*tuh_msc_complete_cb_t)(uint8_t dev_addr, msc_cbw_t const* cbw, msc_csw_t const* csw);
 
-/** \brief      Get SCSI product's name of MassStorage device
- * \param[in]   dev_addr device address
- * \return      pointer to product's name or NULL if specified device does not support MassStorage
- * \note        SCSI product's name is 16-byte length field in \ref scsi_inquiry_data_t. During enumeration, the stack has already
- *              retrieved (via SCSI INQUIRY) and store this information internally. There is no need for application to re-send SCSI INQUIRY
- *              command or allocate buffer for this.
- */
-uint8_t const* tuh_msc_get_product_name(uint8_t dev_addr);
+//--------------------------------------------------------------------+
+// Application API
+//--------------------------------------------------------------------+
 
-/** \brief      Get SCSI Capacity of MassStorage device
- * \param[in]   dev_addr device address
- * \param[out]  p_last_lba Last Logical Block Address of device
- * \param[out]  p_block_size Block Size of device in bytes
- * \retval      pointer to product's name or NULL if specified device does not support MassStorage
- * \note        MassStorage's capacity can be computed by last LBA x block size (in bytes). During enumeration, the stack has already
- *              retrieved (via SCSI READ CAPACITY 10) and store this information internally. There is no need for application
- *              to re-send SCSI READ CAPACITY 10 command
- */
-tusb_error_t tuh_msc_get_capacity(uint8_t dev_addr, uint32_t* p_last_lba, uint32_t* p_block_size);
+// Check if device supports MassStorage interface.
+// This function true after tuh_msc_mounted_cb() and false after tuh_msc_unmounted_cb()
+bool tuh_msc_mounted(uint8_t dev_addr);
 
-/** \brief 			Perform SCSI READ 10 command to read data from MassStorage device
- * \param[in]		dev_addr	device address
- * \param[in]		lun       Targeted Logical Unit
- * \param[out]	p_buffer  Buffer used to store data read from device. Must be accessible by USB controller (see \ref CFG_TUSB_MEM_SECTION)
- * \param[in]		lba       Starting Logical Block Address to be read
- * \param[in]		block_count Number of Block to be read
- * \retval      TUSB_ERROR_NONE on success
- * \retval      TUSB_ERROR_INTERFACE_IS_BUSY if the interface is already transferring data with device
- * \retval      TUSB_ERROR_DEVICE_NOT_READY if device is not yet configured (by SET CONFIGURED request)
- * \retval      TUSB_ERROR_INVALID_PARA if input parameters are not correct
- * \note        This function is non-blocking and returns immediately. The result of USB transfer will be reported by the interface's callback function
- */
-tusb_error_t tuh_msc_read10 (uint8_t dev_addr, uint8_t lun, void * p_buffer, uint32_t lba, uint16_t block_count);
+// Check if the interface is currently ready or busy transferring data
+bool tuh_msc_ready(uint8_t dev_addr);
 
-/** \brief 			Perform SCSI WRITE 10 command to write data to MassStorage device
- * \param[in]		dev_addr	device address
- * \param[in]		lun       Targeted Logical Unit
- * \param[in]	  p_buffer  Buffer containing data. Must be accessible by USB controller (see \ref CFG_TUSB_MEM_SECTION)
- * \param[in]		lba       Starting Logical Block Address to be written
- * \param[in]		block_count Number of Block to be written
- * \retval      TUSB_ERROR_NONE on success
- * \retval      TUSB_ERROR_INTERFACE_IS_BUSY if the interface is already transferring data with device
- * \retval      TUSB_ERROR_DEVICE_NOT_READY if device is not yet configured (by SET CONFIGURED request)
- * \retval      TUSB_ERROR_INVALID_PARA if input parameters are not correct
- * \note        This function is non-blocking and returns immediately. The result of USB transfer will be reported by the interface's callback function
- */
-tusb_error_t tuh_msc_write10(uint8_t dev_addr, uint8_t lun, void const * p_buffer, uint32_t lba, uint16_t block_count);
+// Get Max Lun
+uint8_t tuh_msc_get_maxlun(uint8_t dev_addr);
 
-/** \brief 			Perform SCSI REQUEST SENSE command, used to retrieve sense data from MassStorage device
- * \param[in]		dev_addr	device address
- * \param[in]		lun       Targeted Logical Unit
- * \param[in]	  p_data    Buffer to store response's data from device. Must be accessible by USB controller (see \ref CFG_TUSB_MEM_SECTION)
- * \retval      TUSB_ERROR_NONE on success
- * \retval      TUSB_ERROR_INTERFACE_IS_BUSY if the interface is already transferring data with device
- * \retval      TUSB_ERROR_DEVICE_NOT_READY if device is not yet configured (by SET CONFIGURED request)
- * \retval      TUSB_ERROR_INVALID_PARA if input parameters are not correct
- * \note        This function is non-blocking and returns immediately. The result of USB transfer will be reported by the interface's callback function
- */
-tusb_error_t tuh_msc_request_sense(uint8_t dev_addr, uint8_t lun, uint8_t *p_data);
+// Get number of block
+uint32_t tuh_msc_get_block_count(uint8_t dev_addr, uint8_t lun);
 
-/** \brief 			Perform SCSI TEST UNIT READY command to test if MassStorage device is ready
- * \param[in]		dev_addr	device address
- * \param[in]		lun       Targeted Logical Unit
- * \retval      TUSB_ERROR_NONE on success
- * \retval      TUSB_ERROR_INTERFACE_IS_BUSY if the interface is already transferring data with device
- * \retval      TUSB_ERROR_DEVICE_NOT_READY if device is not yet configured (by SET CONFIGURED request)
- * \retval      TUSB_ERROR_INVALID_PARA if input parameters are not correct
- * \note        This function is non-blocking and returns immediately. The result of USB transfer will be reported by the interface's callback function
- */
-tusb_error_t tuh_msc_test_unit_ready(uint8_t dev_addr, uint8_t lun, msc_csw_t * p_csw); // TODO to be refractor
+// Get block size in bytes
+uint32_t tuh_msc_get_block_size(uint8_t dev_addr, uint8_t lun);
 
-//tusb_error_t  tusbh_msc_scsi_send(uint8_t dev_addr, uint8_t lun, bool is_direction_in,
-//                                  uint8_t const * p_command, uint8_t cmd_len,
-//                                  uint8_t * p_response, uint32_t resp_len);
+// Perform a full SCSI command (cbw, data, csw) in non-blocking manner.
+// Complete callback is invoked when SCSI op is complete.
+// return true if success, false if there is already pending operation.
+bool tuh_msc_scsi_command(uint8_t dev_addr, msc_cbw_t const* cbw, void* data, tuh_msc_complete_cb_t complete_cb);
 
-//------------- Application Callback -------------//
-/** \brief 			Callback function that will be invoked when a device with MassStorage interface is mounted
- * \param[in]	  dev_addr Address of newly mounted device
- * \note        This callback should be used by Application to set-up interface-related data
- */
-void tuh_msc_mounted_cb(uint8_t dev_addr);
+// Perform SCSI Inquiry command
+// Complete callback is invoked when SCSI op is complete.
+bool tuh_msc_inquiry(uint8_t dev_addr, uint8_t lun, scsi_inquiry_resp_t* response, tuh_msc_complete_cb_t complete_cb);
 
-/** \brief 			Callback function that will be invoked when a device with MassStorage interface is unmounted
- * \param[in] 	dev_addr Address of newly unmounted device
- * \note        This callback should be used by Application to tear-down interface-related data
- */
-void tuh_msc_unmounted_cb(uint8_t dev_addr);
+// Perform SCSI Test Unit Ready command
+// Complete callback is invoked when SCSI op is complete.
+bool tuh_msc_test_unit_ready(uint8_t dev_addr, uint8_t lun, tuh_msc_complete_cb_t complete_cb);
 
-/** \brief      Callback function that is invoked when an transferring event occurred
- * \param[in]		dev_addr	Address of device
- * \param[in]   event an value from \ref xfer_result_t
- * \param[in]   xferred_bytes Number of bytes transferred via USB bus
- * \note        event can be one of following
- *              - XFER_RESULT_SUCCESS : previously scheduled transfer completes successfully.
- *              - XFER_RESULT_FAILED   : previously scheduled transfer encountered a transaction error.
- *              - XFER_RESULT_STALLED : previously scheduled transfer is stalled by device.
- * \note
- */
-void tuh_msc_isr(uint8_t dev_addr, xfer_result_t event, uint32_t xferred_bytes);
+// Perform SCSI Request Sense 10 command
+// Complete callback is invoked when SCSI op is complete.
+bool tuh_msc_request_sense(uint8_t dev_addr, uint8_t lun, void *resposne, tuh_msc_complete_cb_t complete_cb);
 
+// Perform SCSI Read 10 command. Read n blocks starting from LBA to buffer
+// Complete callback is invoked when SCSI op is complete.
+bool  tuh_msc_read10(uint8_t dev_addr, uint8_t lun, void * buffer, uint32_t lba, uint16_t block_count, tuh_msc_complete_cb_t complete_cb);
 
-//--------------------------------------------------------------------+
-// Internal Class Driver API
-//--------------------------------------------------------------------+
-typedef struct
-{
-  uint8_t itf_numr;
-  uint8_t  ep_in;
-  uint8_t  ep_out;
+// Perform SCSI Write 10 command. Write n blocks starting from LBA to device
+// Complete callback is invoked when SCSI op is complete.
+bool tuh_msc_write10(uint8_t dev_addr, uint8_t lun, void const * buffer, uint32_t lba, uint16_t block_count, tuh_msc_complete_cb_t complete_cb);
 
-  uint8_t  max_lun;
-  uint16_t block_size;
-  uint32_t last_lba; // last logical block address
+// Perform SCSI Read Capacity 10 command
+// Complete callback is invoked when SCSI op is complete.
+// Note: during enumeration, host stack already carried out this request. Application can retrieve capacity by
+// simply call tuh_msc_get_block_count() and tuh_msc_get_block_size()
+bool tuh_msc_read_capacity(uint8_t dev_addr, uint8_t lun, scsi_read_capacity10_resp_t* response, tuh_msc_complete_cb_t complete_cb);
 
-  volatile bool is_initialized;
-  uint8_t vendor_id[8];
-  uint8_t product_id[16];
+//------------- Application Callback -------------//
 
-  msc_cbw_t cbw;
-  msc_csw_t csw;
-}msch_interface_t;
+// Invoked when a device with MassStorage interface is mounted
+TU_ATTR_WEAK void tuh_msc_mount_cb(uint8_t dev_addr);
 
-void msch_init(void);
-bool msch_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t *p_length);
-void msch_isr(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
-void msch_close(uint8_t dev_addr);
+// Invoked when a device with MassStorage interface is unmounted
+TU_ATTR_WEAK void tuh_msc_umount_cb(uint8_t dev_addr);
+
+//--------------------------------------------------------------------+
+// Internal Class Driver API
+//--------------------------------------------------------------------+
+
+void msch_init       (void);
+bool msch_open       (uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *desc_itf, uint16_t max_len);
+bool msch_set_config (uint8_t dev_addr, uint8_t itf_num);
+void msch_close      (uint8_t dev_addr);
+bool msch_xfer_cb    (uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
 
 #ifdef __cplusplus
  }
 #endif
 
 #endif /* _TUSB_MSC_HOST_H_ */
-
-/// @}
-/// @}