correct waklaround with only status IN

correct usb descriptor msc dual example to work with samg

examples/device/cdc_msc/src/usb_descriptors.c

@@ -95,7 +95,7 @@ enum
   #define EPNUM_MSC_IN      0x85
 
 #elif CFG_TUSB_MCU == OPT_MCU_SAMG
-  // SAMG doesn't support a same endpoint number with IN and OUT
+  // SAMG doesn't support a same endpoint number with different direction IN and OUT
   //    e.g EP1 OUT & EP1 IN cannot exist together
   #define EPNUM_CDC_NOTIF   0x81
   #define EPNUM_CDC_OUT     0x02

examples/device/msc_dual_lun/src/usb_descriptors.c

@@ -80,10 +80,20 @@ enum
 
 #if CFG_TUSB_MCU == OPT_MCU_LPC175X_6X || CFG_TUSB_MCU == OPT_MCU_LPC177X_8X || CFG_TUSB_MCU == OPT_MCU_LPC40XX
   // LPC 17xx and 40xx endpoint type (bulk/interrupt/iso) are fixed by its number
-  // 0 control, 1 In, 2 Bulk, 3 Iso, 4 In etc ...
+  //  0 control, 1 In, 2 Bulk, 3 Iso, 4 In, 5 Bulk etc ...
-  #define EPNUM_MSC   0x02
+  #define EPNUM_MSC_OUT   0x02
+  #define EPNUM_MSC_IN    0x82
+
+#elif CFG_TUSB_MCU == OPT_MCU_SAMG
+  // SAMG doesn't support a same endpoint number with different direction IN and OUT
+  //  e.g EP1 OUT & EP1 IN cannot exist together
+  #define EPNUM_MSC_OUT   0x01
+  #define EPNUM_MSC_IN    0x82
+
 #else
-  #define EPNUM_MSC   0x01
+  #define EPNUM_MSC_OUT   0x01
+  #define EPNUM_MSC_IN    0x81
+
 #endif
 
 uint8_t const desc_configuration[] =
@@ -92,7 +102,7 @@ uint8_t const desc_configuration[] =
   TUD_CONFIG_DESCRIPTOR(ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, TUSB_DESC_CONFIG_ATT_REMOTE_WAKEUP, 100),
 
   // Interface number, string index, EP Out & EP In address, EP size
-  TUD_MSC_DESCRIPTOR(ITF_NUM_MSC, 0, EPNUM_MSC, 0x80 | EPNUM_MSC, (CFG_TUSB_RHPORT0_MODE & OPT_MODE_HIGH_SPEED) ? 512 : 64),
+  TUD_MSC_DESCRIPTOR(ITF_NUM_MSC, 0, EPNUM_MSC_OUT, EPNUM_MSC_IN, (CFG_TUSB_RHPORT0_MODE & OPT_MODE_HIGH_SPEED) ? 512 : 64),
 };
 
 // Invoked when received GET CONFIGURATION DESCRIPTOR

src/portable/microchip/samg/dcd_samg.c

@@ -54,6 +54,7 @@ xfer_desc_t _dcd_xfer[EP_COUNT];
 // Indicate that DATA Toggle for Control Status is incorrect, which must always be DATA1 by USB Specs.
 // However SAMG DToggle is read-only, therefore we must duplicate the status phase ( D0 then D1 )
 // as walk-around to resolve this. The D0 status packet is likely to be discarded by USB Host safely.
+// Note: Only needed for IN Status e.g CDC_SET_LINE_CODING, since out data is sent by host
 volatile bool _walkaround_incorrect_dtoggle_control_status;
 
 void xfer_epsize_set(xfer_desc_t* xfer, uint16_t epsize)
@@ -255,46 +256,43 @@ bool dcd_edpt_xfer (uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t
   xfer_desc_t* xfer = &_dcd_xfer[epnum];
   xfer_begin(xfer, buffer, total_bytes);
 
-  // Control Endpoint direction and data toggle
+  if (dir == TUSB_DIR_OUT)
-  if (epnum == 0)
   {
-    // Transfer direction is opposite to one previously set on EP0
+    // Clear EP0 direction bit
-    // This transfer is Control Status Stage
+    if (epnum == 0) UDP->UDP_CSR[epnum] &= ~UDP_CSR_DIR_Msk;
-    if ( dir != tu_bit_test(UDP->UDP_CSR[epnum], UDP_CSR_DIR_Pos) )
-    {
-      // Set/Clear DIR bit accordingly
-      if (dir)
-      {
-        UDP->UDP_CSR[epnum] |= UDP_CSR_DIR_Msk;
-      }else
-      {
-        UDP->UDP_CSR[epnum] &= ~UDP_CSR_DIR_Msk;
-      }
 
-      // DATA Toggle is 0, USB Specs requires Status Stage must be DATA1
+    // Enable interrupt when starting OUT transfer
-      // Since SAMG DToggle is read-only, we mark this and implement a walk-around
+    if (epnum != 0) UDP->UDP_IER |= (1 << epnum);
-      if ( !(UDP->UDP_CSR[epnum] & UDP_CSR_DTGLE_Msk) )
-      {
-        TU_LOG2("Incorrect DATA TOGGLE, Control Status must be DATA1\n");
-
-        // DTGLE is read-only on SAMG, this statement has no effect
-        UDP->UDP_CSR[epnum] |= UDP_CSR_DTGLE_Msk;
-
-        _walkaround_incorrect_dtoggle_control_status = true;
-      }
-    }
   }
-
+  else
-
-  if (dir == TUSB_DIR_IN)
   {
-    // WALKROUND: duplicate IN transfer to send DATA1 status packet
+    if (epnum == 0)
-    if (_walkaround_incorrect_dtoggle_control_status)
     {
-      UDP->UDP_CSR[epnum] |= UDP_CSR_TXPKTRDY_Msk;
+      // Previous EP0 direction is OUT --> This transfer is ZLP control status.
-      while ( UDP->UDP_CSR[epnum] & UDP_CSR_TXPKTRDY_Msk ) {}
+      if ( !(UDP->UDP_CSR[epnum] & UDP_CSR_DIR_Msk) )
+      {
+        // Set EP0 dir bit
+        UDP->UDP_CSR[epnum] |= UDP_CSR_DIR_Msk;
 
-      _walkaround_incorrect_dtoggle_control_status = false;
+        // DATA Toggle is 0, USB Specs requires Status Stage must be DATA1
+        // Since SAMG DToggle is read-only, we mark this and implement the walk-around
+        if ( !(UDP->UDP_CSR[epnum] & UDP_CSR_DTGLE_Msk) )
+        {
+          TU_LOG2("Incorrect DATA TOGGLE, Control Status must be DATA1\n");
+
+          // DTGLE is read-only on SAMG, this statement has no effect
+          UDP->UDP_CSR[epnum] |= UDP_CSR_DTGLE_Msk;
+
+          // WALKROUND: duplicate IN transfer to send DATA1 status packet
+          // set flag for irq to skip reporting first incorrect packet
+          _walkaround_incorrect_dtoggle_control_status = true;
+
+          UDP->UDP_CSR[epnum] |= UDP_CSR_TXPKTRDY_Msk;
+          while ( UDP->UDP_CSR[epnum] & UDP_CSR_TXPKTRDY_Msk ) {}
+
+          _walkaround_incorrect_dtoggle_control_status = false;
+        }
+      }
     }
 
     xact_ep_write(epnum, xfer->buffer, xfer_packet_len(xfer));
@@ -302,11 +300,6 @@ bool dcd_edpt_xfer (uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t
     // TX ready for transfer
     UDP->UDP_CSR[epnum] |= UDP_CSR_TXPKTRDY_Msk;
   }
-  else
-  {
-    // Enable interrupt when starting OUT transfer
-    if (epnum != 0) UDP->UDP_IER |= (1 << epnum);
-  }
 
   return true;
 }
@@ -422,7 +415,7 @@ void dcd_isr(uint8_t rhport)
           UDP->UDP_CSR[epnum] |= UDP_CSR_TXPKTRDY_Msk;
         }else
         {
-          // WALKAROUND: Skip reporting this incorrect DATA Toggle status transfer
+          // WALKAROUND: Skip reporting this incorrect DATA Toggle status IN transfer
           if ( !(_walkaround_incorrect_dtoggle_control_status && (epnum == 0) && (xfer->actual_len == 0)) )
           {
             // xfer is complete