Merge branch 'master' into ncm

5 files changed, 476 insertions, 519 deletions

diff --git a/src/class/msc/msc.h b/src/class/msc/msc.h
index cba8066b7..0bdc00692 100644
--- a/src/class/msc/msc.h
+++ b/src/class/msc/msc.h
@@ -255,7 +255,7 @@ 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;
diff --git a/src/class/msc/msc_device.c b/src/class/msc/msc_device.c
index f3f2e536e..194f4d3cb 100644
--- a/src/class/msc/msc_device.c
+++ b/src/class/msc/msc_device.c
@@ -71,6 +71,7 @@ CFG_TUSB_MEM_SECTION CFG_TUSB_MEM_ALIGN static uint8_t _mscd_buf[CFG_TUD_MSC_EP_
 //--------------------------------------------------------------------+
 // 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);
 
@@ -186,10 +187,14 @@ uint16_t mscd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint1
   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);
 
@@ -219,190 +224,6 @@ 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;
@@ -592,6 +413,24 @@ bool mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t
         TU_LOG2("  SCSI Status: %u\r\n", p_csw->status);
         // TU_LOG2_MEM(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;
 
@@ -615,24 +454,6 @@ bool mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t
     }
     else
     {
-      // 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 Status Sent stage
       p_msc->stage = MSC_STAGE_STATUS_SENT;
 
@@ -647,6 +468,180 @@ 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 3aa93ffd7..469f2f2f7 100644
--- a/src/class/msc/msc_device.h
+++ b/src/class/msc/msc_device.h
@@ -158,12 +158,11 @@ 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);
-uint16_t mscd_open             (uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t max_len);
-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 539e98376..02ca81e77 100644
--- a/src/class/msc/msc_host.c
+++ b/src/class/msc/msc_host.c
@@ -37,53 +37,63 @@
 //--------------------------------------------------------------------+
 // 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,
+};
+
+typedef struct
+{
+  uint8_t  itf_num;
+  uint8_t  ep_in;
+  uint8_t  ep_out;
+
+  uint8_t  max_lun;
 
-//------------- Initalization Data -------------//
-static osal_semaphore_def_t msch_sem_def;
-static osal_semaphore_t msch_sem_hdl;
+  volatile bool mounted;
+
+  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_data[CFG_TUSB_HOST_DEVICE_MAX];
 
 // 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)];
 
-//--------------------------------------------------------------------+
-// INTERNAL OBJECT & FUNCTION DECLARATION
-//--------------------------------------------------------------------+
+static inline msch_interface_t* get_itf(uint8_t dev_addr)
+{
+  return &msch_data[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)
+bool tuh_msc_mounted(uint8_t dev_addr)
 {
-  return  msch_data[dev_addr-1].is_initialized &&
-          hcd_edpt_busy(dev_addr, msch_data[dev_addr-1].ep_in);
-}
-
-uint8_t const* tuh_msc_get_vendor_name(uint8_t dev_addr)
-{
-  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);
 
-uint8_t const* tuh_msc_get_product_name(uint8_t dev_addr)
-{
-  return msch_data[dev_addr-1].is_initialized ? msch_data[dev_addr-1].product_id : NULL;
+  // is configured can be omitted
+  return tuh_device_is_configured(dev_addr) && 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_is_busy(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 && hcd_edpt_busy(dev_addr, p_msc->ep_in);
 }
 
 //--------------------------------------------------------------------+
@@ -92,131 +102,98 @@ tusb_error_t tuh_msc_get_capacity(uint8_t dev_addr, uint32_t* p_last_lba, uint32
 static inline void msc_cbw_add_signature(msc_cbw_t *p_cbw, uint8_t lun)
 {
   p_cbw->signature  = MSC_CBW_SIGNATURE;
-  p_cbw->tag        = 0xCAFECAFE;
+  p_cbw->tag        = 0x54555342; // TUSB
   p_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->mounted); // TODO part of the enumeration also use scsi command
 
-  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);
+  if ( !p_msc->mounted ) return false;
 
-  memcpy(p_msch->cbw.command, &cmd_inquiry, p_msch->cbw.cmd_len);
+  msc_cbw_t cbw = { 0 };
 
-  TU_ASSERT_ERR ( msch_command_xfer(dev_addr, p_msch, p_data) );
+  msc_cbw_add_signature(&cbw, lun);
+  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_scsi_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];
+  msc_cbw_t cbw = { 0 };
 
-  //------------- 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_add_signature(&cbw, lun);
+  cbw.total_bytes = sizeof(scsi_inquiry_resp_t);
+  cbw.dir         = TUSB_DIR_IN_MASK;
+  cbw.cmd_len     = sizeof(scsi_inquiry_t);
 
-  //------------- SCSI command -------------//
-  scsi_read_capacity10_t cmd_read_capacity10 =
+  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);
 
-  memcpy(p_msch->cbw.command, &cmd_read_capacity10, p_msch->cbw.cmd_len);
-
-  TU_ASSERT_ERR ( msch_command_xfer(dev_addr, p_msch, p_data) );
-
-  return TUSB_ERROR_NONE;
+  return tuh_msc_scsi_command(dev_addr, &cbw, response, complete_cb);
 }
 
-tusb_error_t tuh_msc_request_sense(uint8_t dev_addr, uint8_t lun, uint8_t *p_data)
+bool tuh_msc_test_unit_ready(uint8_t dev_addr, uint8_t lun, tuh_msc_complete_cb_t complete_cb)
 {
-  (void) lun; // TODO [MSCH] multiple lun support
+  msc_cbw_t cbw = { 0 };
+  msc_cbw_add_signature(&cbw, lun);
 
-  msch_interface_t* p_msch = &msch_data[dev_addr-1];
-
-  //------------- 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);
+  cbw.total_bytes = 0; // Number of bytes
+  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
 
-  //------------- SCSI command -------------//
-  scsi_request_sense_t cmd_request_sense =
-  {
-      .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) );
-
-  return TUSB_ERROR_NONE;
+  return tuh_msc_scsi_command(dev_addr, &cbw, NULL, 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_request_sense(uint8_t dev_addr, uint8_t lun, void *resposne, tuh_msc_complete_cb_t complete_cb)
 {
-  msch_interface_t* p_msch = &msch_data[dev_addr-1];
+  msc_cbw_t cbw = { 0 };
+  msc_cbw_add_signature(&cbw, lun);
 
-  //------------- Command Block Wrapper -------------//
-  msc_cbw_add_signature(&p_msch->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 = 18; // TODO sense response
+  cbw.dir        = TUSB_DIR_IN_MASK;
+  cbw.cmd_len    = sizeof(scsi_request_sense_t);
 
-  //------------- SCSI command -------------//
-  scsi_test_unit_ready_t cmd_test_unit_ready =
+  scsi_request_sense_t const cmd_request_sense =
   {
-      .cmd_code = SCSI_CMD_TEST_UNIT_READY,
-      .lun      = lun // according to wiki
+    .cmd_code     = SCSI_CMD_REQUEST_SENSE,
+    .alloc_length = 18
   };
 
-  memcpy(p_msch->cbw.command, &cmd_test_unit_ready, p_msch->cbw.cmd_len);
+  memcpy(cbw.command, &cmd_request_sense, 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 );
-
-  return TUSB_ERROR_NONE;
+  return tuh_msc_scsi_command(dev_addr, &cbw, resposne, complete_cb);
 }
 
+#if 0
+
 tusb_error_t  tuh_msc_read10(uint8_t dev_addr, uint8_t lun, void * p_buffer, uint32_t lba, uint16_t block_count)
 {
   msch_interface_t* p_msch = &msch_data[dev_addr-1];
@@ -229,7 +206,7 @@ tusb_error_t  tuh_msc_read10(uint8_t dev_addr, uint8_t lun, void * p_buffer, uin
   p_msch->cbw.cmd_len    = sizeof(scsi_read10_t);
 
   //------------- SCSI command -------------//
-  scsi_read10_t cmd_read10 =
+  scsi_read10_t cmd_read10 =msch_sem_hdl
   {
       .cmd_code    = SCSI_CMD_READ_10,
       .lba         = tu_htonl(lba),
@@ -238,7 +215,7 @@ tusb_error_t  tuh_msc_read10(uint8_t dev_addr, uint8_t lun, void * p_buffer, uin
 
   memcpy(p_msch->cbw.command, &cmd_read10, p_msch->cbw.cmd_len);
 
-  TU_ASSERT_ERR ( msch_command_xfer(dev_addr, p_msch, p_buffer));
+  TU_ASSERT_ERR ( send_cbw(dev_addr, p_msch, p_buffer));
 
   return TUSB_ERROR_NONE;
 }
@@ -264,10 +241,32 @@ tusb_error_t tuh_msc_write10(uint8_t dev_addr, uint8_t lun, void const * p_buffe
 
   memcpy(p_msch->cbw.command, &cmd_write10, p_msch->cbw.cmd_len);
 
-  TU_ASSERT_ERR ( msch_command_xfer(dev_addr, p_msch, (void*) p_buffer));
+  TU_ASSERT_ERR ( send_cbw(dev_addr, p_msch, (void*) p_buffer));
 
   return TUSB_ERROR_NONE;
 }
+#endif
+
+#if 0
+// MSC interface Reset (not used now)
+bool tuh_msc_reset(uint8_t dev_addr)
+{
+  tusb_control_request_t const new_request =
+  {
+    .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 (don't require to verify parameters)
@@ -275,24 +274,83 @@ tusb_error_t tuh_msc_write10(uint8_t dev_addr, uint8_t lun, void const * p_buffe
 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);
 }
 
+void msch_close(uint8_t dev_addr)
+{
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  tu_memclr(p_msc, sizeof(msch_interface_t));
+  tuh_msc_unmounted_cb(dev_addr); // invoke Application Callback
+}
+
+bool msch_xfer_cb(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes)
+{
+  msch_interface_t* p_msc = get_itf(dev_addr);
+  msc_cbw_t const * cbw = &p_msc->cbw;
+  msc_csw_t       * csw = &p_msc->csw;
+
+  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));
+
+      if ( cbw->total_bytes && p_msc->buffer )
+      {
+        // Data stage if any
+        p_msc->stage = MSC_STAGE_DATA;
+
+        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;
+
+    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;
+
+    case MSC_STAGE_STATUS:
+      // SCSI op is complete
+      p_msc->stage = MSC_STAGE_IDLE;
+
+      if (p_msc->complete_cb) p_msc->complete_cb(dev_addr, cbw, csw);
+    break;
+
+    // unknown state
+    default: break;
+  }
+
+  return true;
+}
+
+//--------------------------------------------------------------------+
+// MSC Enumeration
+//--------------------------------------------------------------------+
+
+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);
+
 bool msch_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t *p_length)
 {
   TU_VERIFY (MSC_SUBCLASS_SCSI == itf_desc->bInterfaceSubClass &&
              MSC_PROTOCOL_BOT  == itf_desc->bInterfaceProtocol);
 
-  msch_interface_t* p_msc = &msch_data[dev_addr-1];
+  msch_interface_t* p_msc = get_itf(dev_addr);
 
   //------------- Open Data Pipe -------------//
   tusb_desc_endpoint_t const * ep_desc = (tusb_desc_endpoint_t const *) tu_desc_next(itf_desc);
 
   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(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 )
@@ -309,106 +367,78 @@ bool msch_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *it
   p_msc->itf_num = itf_desc->bInterfaceNumber;
   (*p_length) += sizeof(tusb_desc_interface_t) + 2*sizeof(tusb_desc_endpoint_t);
 
-  //------------- Get Max Lun -------------//
-  TU_LOG2("MSC Get Max Lun\r\n");
-  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_num,
-        .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_num,
-        .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) );
-
-  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);
+  return true;
+}
 
-  //------------- SCSI Read Capacity 10 -------------//
-  tusbh_msc_read_capacity10(dev_addr, 0, msch_buffer);
-  TU_ASSERT( osal_semaphore_wait(msch_sem_hdl, SCSI_XFER_TIMEOUT));
+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);
 
-  // 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");
+  tuh_msc_test_unit_ready(dev_addr, 0, 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);
-    }
+    msch_interface_t* p_msc = get_itf(dev_addr);
+
+    usbh_driver_set_config_complete(dev_addr, p_msc->itf_num);
+
+    // Unit is ready, Enumeration is complete
+    p_msc->mounted = true;
+    tuh_msc_mounted_cb(dev_addr);
+  }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_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
-//--------------------------------------------------------------------+
-
-
 #endif
diff --git a/src/class/msc/msc_host.h b/src/class/msc/msc_host.h
index 959294adf..5913350b8 100644
--- a/src/class/msc/msc_host.h
+++ b/src/class/msc/msc_host.h
@@ -40,15 +40,16 @@
  * \defgroup MSC_Host Host
  *  The interface API includes status checking function, data transferring function and callback functions
  *  @{ */
+
+typedef bool (*tuh_msc_complete_cb_t)(uint8_t dev_addr, msc_cbw_t const* cbw, msc_csw_t const* csw);
+
 //--------------------------------------------------------------------+
-// MASS STORAGE Application API
+// Application API
 //--------------------------------------------------------------------+
-/** \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);
+
+// 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      Check if the interface is currently busy or not
  * \param[in]   dev_addr device address
@@ -60,35 +61,27 @@ bool          tuh_msc_is_mounted(uint8_t dev_addr);
  */
 bool          tuh_msc_is_busy(uint8_t dev_addr);
 
-/** \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);
+// Get Max Lun
+uint8_t tuh_msc_get_maxlun(uint8_t dev_addr);
 
-/** \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);
+// Carry out a full SCSI command (cbw, data, csw) in non-blocking manner.
+// `complete_cb` 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);
 
-/** \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);
+// Carry out SCSI INQUIRY command in non-blocking manner.
+bool tuh_msc_scsi_inquiry(uint8_t dev_addr, uint8_t lun, scsi_inquiry_resp_t* response, tuh_msc_complete_cb_t complete_cb);
+
+// Carry out SCSI REQUEST SENSE (10) command in non-blocking manner.
+bool tuh_msc_test_unit_ready(uint8_t dev_addr, uint8_t lun, tuh_msc_complete_cb_t complete_cb);
 
+// Carry out SCSI REQUEST SENSE (10) command in non-blocking manner.
+bool tuh_msc_request_sense(uint8_t dev_addr, uint8_t lun, void *resposne, tuh_msc_complete_cb_t complete_cb);
+
+// Carry out SCSI READ CAPACITY (10) command in non-blocking manner.
+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);
+
+#if 0
 /** \brief 			Perform SCSI READ 10 command to read data from MassStorage device
  * \param[in]		dev_addr	device address
  * \param[in]		lun       Targeted Logical Unit
@@ -116,84 +109,24 @@ tusb_error_t tuh_msc_read10 (uint8_t dev_addr, uint8_t lun, void * p_buffer, uin
  * \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);
-
-/** \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);
-
-/** \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
-
-//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);
+#endif
 
 //------------- 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
- */
+
+// Invoked when a device with MassStorage interface is mounted
 void tuh_msc_mounted_cb(uint8_t dev_addr);
 
-/** \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
- */
+// Invoked when a device with MassStorage interface is unmounted
 void tuh_msc_unmounted_cb(uint8_t dev_addr);
 
-/** \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);
-
-
 //--------------------------------------------------------------------+
 // Internal Class Driver API
 //--------------------------------------------------------------------+
-typedef struct
-{
-  uint8_t  itf_num;
-  uint8_t  ep_in;
-  uint8_t  ep_out;
-
-  uint8_t  max_lun;
-  uint16_t block_size;
-  uint32_t last_lba; // last logical block address
-
-  volatile bool is_initialized;
-  uint8_t vendor_id[8];
-  uint8_t product_id[16];
-
-  msc_cbw_t cbw;
-  msc_csw_t csw;
-}msch_interface_t;
 
 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);
+bool msch_set_config(uint8_t dev_addr, uint8_t itf_num);
+bool msch_xfer_cb(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
 void msch_close(uint8_t dev_addr);
 
 #ifdef __cplusplus