Implement dcd_edpt_iso_xfer() for dcd_stm32_fsdev

Implemented a special copy strategy to copy directly from the FIFO. This
function, however, is untested and should be regarded as unreliable
until somebody was able to test it

src/portable/st/stm32_fsdev/dcd_stm32_fsdev.c

@@ -102,6 +102,7 @@
  */
 
 #include "tusb_option.h"
+#include "common/tusb_fifo.h"
 
 #if defined(STM32F102x6) || defined(STM32F102xB) || \
     defined(STM32F103x6) || defined(STM32F103xB) || \
@@ -165,6 +166,7 @@ TU_VERIFY_STATIC(((DCD_STM32_BTABLE_BASE) % 8) == 0, "BTABLE base must be aligne
 typedef struct
 {
   uint8_t * buffer;
+  tu_fifo_t * ff;
   uint16_t total_len;
   uint16_t queued_len;
   uint16_t pma_ptr;
@@ -195,7 +197,9 @@ static void dcd_pma_alloc_reset(void);
 static uint16_t dcd_pma_alloc(uint8_t ep_addr, size_t length);
 static void dcd_pma_free(uint8_t ep_addr);
 static bool dcd_write_packet_memory(uint16_t dst, const void *__restrict src, size_t wNBytes);
+static bool dcd_write_packet_memory_ff(tu_fifo_t * ff, uint16_t dst, uint16_t wNBytes);
 static bool dcd_read_packet_memory(void *__restrict dst, uint16_t src, size_t wNBytes);
+static bool dcd_read_packet_memory_ff(tu_fifo_t * ff, uint16_t src, uint16_t wNBytes);
 
 // Using a function due to better type checks
 // This seems better than having to do type casts everywhere else
@@ -476,8 +480,16 @@ static void dcd_ep_ctr_rx_handler(uint32_t wIstr)
 
     if (count != 0U)
     {
-      dcd_read_packet_memory(&(xfer->buffer[xfer->queued_len]),
-        *pcd_ep_rx_address_ptr(USB,EPindex), count);
+      if (xfer->ff)
+      {
+        dcd_read_packet_memory_ff(xfer->ff, *pcd_ep_rx_address_ptr(USB,EPindex), count);
+      }
+      else
+      {
+        dcd_read_packet_memory(&(xfer->buffer[xfer->queued_len]),
+                *pcd_ep_rx_address_ptr(USB,EPindex), count);
+      }
+
       xfer->queued_len = (uint16_t)(xfer->queued_len + count);
     }
 
@@ -804,7 +816,14 @@ static void dcd_transmit_packet(xfer_ctl_t * xfer, uint16_t ep_ix)
     len = xfer->max_packet_size;
   }
   uint16_t oldAddr = *pcd_ep_tx_address_ptr(USB,ep_ix);
-  dcd_write_packet_memory(oldAddr, &(xfer->buffer[xfer->queued_len]), len);
+  if (xfer->ff)
+  {
+    dcd_write_packet_memory_ff(xfer->ff, oldAddr, len);
+  }
+  else
+  {
+    dcd_write_packet_memory(oldAddr, &(xfer->buffer[xfer->queued_len]), len);
+  }
   xfer->queued_len = (uint16_t)(xfer->queued_len + len);
 
   pcd_set_ep_tx_cnt(USB,ep_ix,len);
@@ -821,6 +840,7 @@ bool dcd_edpt_xfer (uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t
   xfer_ctl_t * xfer = xfer_ctl_ptr(epnum,dir);
 
   xfer->buffer = buffer;
+  xfer->ff     = NULL;
   xfer->total_len = total_bytes;
   xfer->queued_len = 0;
 
@@ -847,6 +867,37 @@ bool dcd_edpt_xfer (uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t
   return true;
 }
 
+bool dcd_edpt_iso_xfer (uint8_t rhport, uint8_t ep_addr, tu_fifo_t * ff, uint16_t total_bytes)
+{
+  (void) rhport;
+
+  uint8_t const epnum = tu_edpt_number(ep_addr);
+  uint8_t const dir   = tu_edpt_dir(ep_addr);
+
+  xfer_ctl_t * xfer = xfer_ctl_ptr(epnum,dir);
+
+  xfer->buffer = NULL;
+  xfer->ff     = ff;
+  xfer->total_len = total_bytes;
+  xfer->queued_len = 0;
+
+  if ( dir == TUSB_DIR_OUT )
+  {
+    if(total_bytes > xfer->max_packet_size)
+    {
+      pcd_set_ep_rx_cnt(USB,epnum,xfer->max_packet_size);
+    } else {
+      pcd_set_ep_rx_cnt(USB,epnum,total_bytes);
+    }
+    pcd_set_ep_rx_status(USB, epnum, USB_EP_RX_VALID);
+  }
+  else // IN
+  {
+    dcd_transmit_packet(xfer,epnum);
+  }
+  return true;
+}
+
 void dcd_edpt_stall (uint8_t rhport, uint8_t ep_addr)
 {
   (void)rhport;
@@ -921,7 +972,52 @@ static bool dcd_write_packet_memory(uint16_t dst, const void *__restrict src, si
 }
 
 /**
-  * @brief Copy a buffer from user memory area to packet memory area (PMA).
+  * @brief Copy from FIFO to packet memory area (PMA).
+  *        Uses byte-access of system memory and 16-bit access of packet memory
+  * @param   wNBytes no. of bytes to be copied.
+  * @retval None
+  */
+
+// THIS FUNCTION IS UNTESTED
+
+static bool dcd_write_packet_memory_ff(tu_fifo_t * ff, uint16_t dst, uint16_t wNBytes)
+{
+  // Since we copy from a ring buffer FIFO, a wrap might occur making it necessary to conduct two copies
+  // Check for first linear part
+  void *__restrict src;
+  uint16_t len = tu_fifo_get_linear_read_info(ff, 0, &src, wNBytes);  // We want to read from the FIFO
+  TU_VERIFY(len && dcd_write_packet_memory(dst, src, len));           // and write it into the PMA
+  tu_fifo_advance_read_pointer(ff, len);
+
+  // Check for wrapped part
+  if (len < wNBytes)
+  {
+    // Get remaining wrapped length
+    uint16_t len2 = tu_fifo_get_linear_read_info(ff, 0, &src, wNBytes - len);
+    TU_VERIFY(len2);
+
+    // Update destination pointer
+    dst += len;
+
+    // Since PMA is accessed 16-bit wise we need to handle the case when a 16 bit value was split
+    if (len % 2)    // If len is uneven there is a byte left to copy
+    {
+      // Since PMA can accessed only 16 bit-wise we copy the last byte again
+      tu_fifo_backward_read_pointer(ff, 1);                 // Move one byte back and copy two bytes for the PMA
+      pma[PMA_STRIDE*(dst>>1)] = tu_fifo_read_n(ff, 2);     // Since EP FIFOs must be of item size 1 this is safe to do
+      dst++;
+      len2--;
+    }
+
+    TU_VERIFY(dcd_write_packet_memory(dst, src, len2));
+    tu_fifo_advance_write_pointer(ff, len2);
+  }
+
+  return true;
+}
+
+/**
+  * @brief Copy a buffer from packet memory area (PMA) to user memory area.
   *        Uses byte-access of system memory and 16-bit access of packet memory
   * @param   wNBytes no. of bytes to be copied.
   * @retval None
@@ -955,5 +1051,49 @@ static bool dcd_read_packet_memory(void *__restrict dst, uint16_t src, size_t wN
   return true;
 }
 
+/**
+  * @brief Copy a buffer from user packet memory area (PMA) to FIFO.
+  *        Uses byte-access of system memory and 16-bit access of packet memory
+  * @param   wNBytes no. of bytes to be copied.
+  * @retval None
+  */
+
+// THIS FUNCTION IS UNTESTED
+
+static bool dcd_read_packet_memory_ff(tu_fifo_t * ff, uint16_t src, uint16_t wNBytes)
+{
+  // Since we copy into a ring buffer FIFO, a wrap might occur making it necessary to conduct two copies
+  // Check for first linear part
+  void *__restrict dst;
+  uint16_t len = tu_fifo_get_linear_write_info(ff, 0, &dst, wNBytes);
+  TU_VERIFY(len && dcd_read_packet_memory(dst, src, len));
+  tu_fifo_advance_write_pointer(ff, len);
+
+  // Check for wrapped part
+  if (len < wNBytes)
+  {
+    // Get remaining wrapped length
+    uint16_t len2 = tu_fifo_get_linear_write_info(ff, 0, &dst, wNBytes - len);
+    TU_VERIFY(len2);
+
+    // Update source pointer
+    src += len;
+
+    // Since PMA is accessed 16-bit wise we need to handle the case when a 16 bit value was split
+    if (len % 2)    // If len is uneven there is a byte left to copy
+    {
+      uint32_t temp = pma[PMA_STRIDE*(src>>1)];
+      *((uint8_t *)dst++) = ((temp >> 8) & 0xFF);
+      src++;
+      len2--;
+    }
+
+    TU_VERIFY(dcd_read_packet_memory(dst, src, len2));
+    tu_fifo_advance_write_pointer(ff, len2);
+  }
+
+  return true;
+}
+
 #endif