nrf5x: clean up dcd, add comment

2 files changed, 73 insertions, 80 deletions

diff --git a/src/device/usbd.c b/src/device/usbd.c
index bf6aa665f..eac1a6a20 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -70,12 +70,10 @@ typedef struct {
   uint8_t itf2drv[16];  // map interface number to driver (0xff is invalid)

   uint8_t ep2drv[2][8]; // map endpoint to driver ( 0xff is invalid )

 

-

 }usbd_device_t;

 

 static usbd_device_t _usbd_dev;

 

-

 // Auto descriptor is enabled, descriptor set point to auto generated one

 #if CFG_TUD_DESC_AUTO

 extern tud_desc_set_t const _usbd_auto_desc_set;

diff --git a/src/portable/nordic/nrf5x/dcd_nrf5x.c b/src/portable/nordic/nrf5x/dcd_nrf5x.c
index fad96acf3..816ff62ae 100644
--- a/src/portable/nordic/nrf5x/dcd_nrf5x.c
+++ b/src/portable/nordic/nrf5x/dcd_nrf5x.c
@@ -64,9 +64,7 @@ enum
                       USBD_INTENCLR_ENDISOIN_Msk | USBD_INTEN_ENDISOOUT_Msk
 };
 
-/*------------------------------------------------------------------*/
-/* VARIABLE DECLARATION
- *------------------------------------------------------------------*/
+// Transfer descriptor
 typedef struct
 {
   uint8_t* buffer;
@@ -78,66 +76,23 @@ typedef struct
   // indicate packet is already ACK
   volatile bool data_received;
 
-} nom_xfer_t;
+} xfer_td_t;
 
-/*static*/ struct
+// Data for managing dcd
+static struct
 {
   // All 8 endpoints including control IN & OUT (offset 1)
-  nom_xfer_t xfer[8][2];
+  xfer_td_t xfer[8][2];
 
+  // Only one DMA can run at a time
   volatile bool dma_running;
 }_dcd;
 
-void bus_reset(void)
-{
-  for(int i=0; i<8; i++)
-  {
-    NRF_USBD->TASKS_STARTEPIN[i] = 0;
-    NRF_USBD->TASKS_STARTEPOUT[i] = 0;
-  }
-
-  NRF_USBD->TASKS_STARTISOIN  = 0;
-  NRF_USBD->TASKS_STARTISOOUT = 0;
-
-  tu_varclr(&_dcd);
-  _dcd.xfer[0][TUSB_DIR_IN].mps = MAX_PACKET_SIZE;
-  _dcd.xfer[0][TUSB_DIR_OUT].mps = MAX_PACKET_SIZE;
-}
-
 /*------------------------------------------------------------------*/
-/* Controller API
+/* Control / Bulk / Interrupt (CBI) Transfer
  *------------------------------------------------------------------*/
-bool dcd_init (uint8_t rhport)
-{
-  (void) rhport;
-  return true;
-}
-
-void dcd_connect (uint8_t rhport)
-{
-
-}
-void dcd_disconnect (uint8_t rhport)
-{
-
-}
-
-void dcd_set_address (uint8_t rhport, uint8_t dev_addr)
-{
-  (void) rhport;
-  // Set Address is automatically update by hw controller
-}
-
-void dcd_set_config (uint8_t rhport, uint8_t config_num)
-{
-  (void) rhport;
-  (void) config_num;
-  // Nothing to do
-}
 
-/*------------------------------------------------------------------*/
-/* Control
- *------------------------------------------------------------------*/
+// helper to start DMA
 static void edpt_dma_start(volatile uint32_t* reg_startep)
 {
   // Only one dma can be active
@@ -162,28 +117,23 @@ static void edpt_dma_start(volatile uint32_t* reg_startep)
   __ISB(); __DSB();
 }
 
+// DMA is complete
 static void edpt_dma_end(void)
 {
   TU_ASSERT(_dcd.dma_running, );
-
   _dcd.dma_running = false;
 }
 
-/*------------------------------------------------------------------*/
-/*
- *------------------------------------------------------------------*/
-
-static inline nom_xfer_t* get_td(uint8_t epnum, uint8_t dir)
+// helper getting td
+static inline xfer_td_t* get_td(uint8_t epnum, uint8_t dir)
 {
   return &_dcd.xfer[epnum][dir];
 }
 
-/*------------- Bulk/Int OUT transfer -------------*/
+/*------------- CBI OUT Transfer -------------*/
 
-/**
- * Prepare Bulk/Int out transaction, Endpoint start to accept/ACK Data
- * @param epnum
- */
+// Prepare for a CBI transaction OUT, call at the start
+// Allow ACK incoming data
 static void xact_out_prepare(uint8_t epnum)
 {
   if ( epnum == 0 )
@@ -200,9 +150,10 @@ static void xact_out_prepare(uint8_t epnum)
   __ISB(); __DSB();
 }
 
+// Start DMA to move data from Endpoint -> RAM
 static void xact_out_dma(uint8_t epnum)
 {
-  nom_xfer_t* xfer = get_td(epnum, TUSB_DIR_OUT);
+  xfer_td_t* xfer = get_td(epnum, TUSB_DIR_OUT);
 
   uint8_t const xact_len = NRF_USBD->SIZE.EPOUT[epnum];
 
@@ -216,16 +167,13 @@ static void xact_out_dma(uint8_t epnum)
   xfer->actual_len += xact_len;
 }
 
+/*------------- CBI IN Transfer -------------*/
 
-/*------------- Bulk/Int IN transfer -------------*/
-
-/**
- * Prepare Bulk/Int in transaction, use DMA to transfer data from Memory -> Endpoint
- * @param epnum
- */
+// Prepare for a CBI transaction IN, call at the start
+// it start DMA to transfer data from RAM -> Endpoint
 static void xact_in_prepare(uint8_t epnum)
 {
-  nom_xfer_t* xfer = get_td(epnum, TUSB_DIR_IN);
+  xfer_td_t* xfer = get_td(epnum, TUSB_DIR_IN);
 
   // Each transaction is up to Max Packet Size
   uint8_t const xact_len = tu_min16(xfer->total_len - xfer->actual_len, xfer->mps);
@@ -238,6 +186,37 @@ static void xact_in_prepare(uint8_t epnum)
   edpt_dma_start(&NRF_USBD->TASKS_STARTEPIN[epnum]);
 }
 
+//--------------------------------------------------------------------+
+// Tinyusb DCD API
+//--------------------------------------------------------------------+
+bool dcd_init (uint8_t rhport)
+{
+  (void) rhport;
+  return true;
+}
+
+void dcd_connect (uint8_t rhport)
+{
+
+}
+void dcd_disconnect (uint8_t rhport)
+{
+
+}
+
+void dcd_set_address (uint8_t rhport, uint8_t dev_addr)
+{
+  (void) rhport;
+  // Set Address is automatically update by hw controller
+}
+
+void dcd_set_config (uint8_t rhport, uint8_t config_num)
+{
+  (void) rhport;
+  (void) config_num;
+  // Nothing to do
+}
+
 bool dcd_edpt_open (uint8_t rhport, tusb_desc_endpoint_t const * desc_edpt)
 {
   (void) rhport;
@@ -268,7 +247,7 @@ bool dcd_edpt_xfer (uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t
   uint8_t const epnum = edpt_number(ep_addr);
   uint8_t const dir   = edpt_dir(ep_addr);
 
-  nom_xfer_t* xfer = get_td(epnum, dir);
+  xfer_td_t* xfer = get_td(epnum, dir);
 
   xfer->buffer     = buffer;
   xfer->total_len  = total_bytes;
@@ -352,14 +331,30 @@ bool dcd_edpt_busy (uint8_t rhport, uint8_t ep_addr)
   uint8_t const epnum = edpt_number(ep_addr);
   uint8_t const dir   = edpt_dir(ep_addr);
 
-  nom_xfer_t* xfer = get_td(epnum, dir);
+  xfer_td_t* xfer = get_td(epnum, dir);
 
   return xfer->actual_len < xfer->total_len;
 }
 
 /*------------------------------------------------------------------*/
-/*
+/* Interrupt Handler
  *------------------------------------------------------------------*/
+void bus_reset(void)
+{
+  for(int i=0; i<8; i++)
+  {
+    NRF_USBD->TASKS_STARTEPIN[i] = 0;
+    NRF_USBD->TASKS_STARTEPOUT[i] = 0;
+  }
+
+  NRF_USBD->TASKS_STARTISOIN  = 0;
+  NRF_USBD->TASKS_STARTISOOUT = 0;
+
+  tu_varclr(&_dcd);
+  _dcd.xfer[0][TUSB_DIR_IN].mps = MAX_PACKET_SIZE;
+  _dcd.xfer[0][TUSB_DIR_OUT].mps = MAX_PACKET_SIZE;
+}
+
 void USBD_IRQHandler(void)
 {
   uint32_t const inten  = NRF_USBD->INTEN;
@@ -448,7 +443,7 @@ void USBD_IRQHandler(void)
   {
     if ( BIT_TEST_(int_status, USBD_INTEN_ENDEPOUT0_Pos+epnum))
     {
-      nom_xfer_t* xfer = get_td(epnum, TUSB_DIR_OUT);
+      xfer_td_t* xfer = get_td(epnum, TUSB_DIR_OUT);
       uint8_t const xact_len = NRF_USBD->EPOUT[epnum].AMOUNT;
 
       // Data in endpoint has been consumed
@@ -488,7 +483,7 @@ void USBD_IRQHandler(void)
     {
       if ( BIT_TEST_(data_status, epnum ) || ( epnum == 0 && is_control_in) )
       {
-        nom_xfer_t* xfer = get_td(epnum, TUSB_DIR_IN);
+        xfer_td_t* xfer = get_td(epnum, TUSB_DIR_IN);
 
         xfer->actual_len += NRF_USBD->EPIN[epnum].MAXCNT;
 
@@ -509,7 +504,7 @@ void USBD_IRQHandler(void)
     {
       if ( BIT_TEST_(data_status, 16+epnum ) || ( epnum == 0 && is_control_out) )
       {
-        nom_xfer_t* xfer = get_td(epnum, TUSB_DIR_OUT);
+        xfer_td_t* xfer = get_td(epnum, TUSB_DIR_OUT);
 
         if (xfer->actual_len < xfer->total_len)
         {