this is tricky

linux/ipcore/PapbVcInterface.cpp

@@ -1,5 +1,6 @@
 #include <fsfw_hal/linux/uio/UioMapper.h>
 #include <linux/ipcore/PapbVcInterface.h>
+#include <unistd.h>
 
 #include "fsfw/serviceinterface/ServiceInterface.h"
 
@@ -15,7 +16,13 @@ PapbVcInterface::~PapbVcInterface() {}
 
 ReturnValue_t PapbVcInterface::initialize() {
   UioMapper uioMapper(uioFile, mapNum);
-  return uioMapper.getMappedAdress(&vcBaseReg, UioMapper::Permissions::WRITE_ONLY);
+  uint32_t* baseReg;
+  ReturnValue_t result = uioMapper.getMappedAdress(&baseReg, UioMapper::Permissions::WRITE_ONLY);
+  if (result != returnvalue::OK) {
+    return result;
+  }
+  vcBaseReg = baseReg;
+  return returnvalue::OK;
 }
 
 ReturnValue_t PapbVcInterface::write(const uint8_t* data, size_t size) {
@@ -24,27 +31,27 @@ ReturnValue_t PapbVcInterface::write(const uint8_t* data, size_t size) {
   }
   for (size_t idx = 0; idx < size; idx++) {
     if (pollPapbBusySignal() == returnvalue::OK) {
-      *(vcBaseReg + DATA_REG_OFFSET) = static_cast<uint32_t>(*(data + idx));
+      *(vcBaseReg + DATA_REG_OFFSET) = static_cast<uint32_t>(data[idx]);
     } else {
-      sif::warning << "PapbVcInterface::write: Only written " << idx << " of " << size << " data"
-                   << std::endl;
-      return returnvalue::FAILED;
+      abortPacketTransfer();
+      return DirectTmSinkIF::IS_BUSY;
     }
   }
   if (pollPapbBusySignal() == returnvalue::OK) {
-    endPacketTransfer();
+    completePacketTransfer();
   }
   return returnvalue::OK;
 }
 
 void PapbVcInterface::startPacketTransfer() { *vcBaseReg = CONFIG_START; }
 
-void PapbVcInterface::endPacketTransfer() { *vcBaseReg = CONFIG_END; }
+void PapbVcInterface::completePacketTransfer() { *vcBaseReg = CONFIG_END; }
 
 ReturnValue_t PapbVcInterface::pollPapbBusySignal() const {
   gpio::Levels papbBusyState = gpio::Levels::LOW;
-  ReturnValue_t result = returnvalue::OK;
+  ReturnValue_t result;
   uint32_t busyIdx = 0;
+  uint32_t delayCount = 0;
 
   while (true) {
     /** Check if PAPB interface is ready to receive data */
@@ -57,12 +64,17 @@ ReturnValue_t PapbVcInterface::pollPapbBusySignal() const {
     if (papbBusyState == gpio::Levels::HIGH) {
       return returnvalue::OK;
     }
-    if (busyIdx == 100) {
+    if (busyIdx == 3) {
+      usleep(100);
+      busyIdx = 0;
+      delayCount += 1;
+      continue;
+    }
+    if (delayCount == 1000) {
       return PAPB_BUSY;
     }
     busyIdx++;
   }
-
   return returnvalue::OK;
 }
 
@@ -104,3 +116,5 @@ ReturnValue_t PapbVcInterface::sendTestFrame() {
 
   return returnvalue::OK;
 }
+
+void PapbVcInterface::abortPacketTransfer() { *vcBaseReg = CONFIG_ABORT; }

linux/ipcore/PapbVcInterface.h

@@ -51,16 +51,21 @@ class PapbVcInterface : public VirtualChannelIF {
   /**
    * Configuration bits:
    * bit[1:0]: Size of data (1,2,3 or 4 bytes). 1 Byte <=> b00
-   * bit[2]: Set this bit to 1 to abort a transfered packet
+   * bit[2]: Set this bit to 1 to abort a transferred packet
    * bit[3]: Signals to VcInterface the start of a new telemetry packet
    */
-  static const uint32_t CONFIG_START = 0x8;
+  static constexpr uint32_t CONFIG_START = 0b00001000;
+
+  /**
+   * Abort a transferred packet.
+   */
+  static constexpr uint32_t CONFIG_ABORT = 0b00000100;
 
   /**
    * Writing this word to the VcInterface base address signals to the virtual channel interface
    * that a complete tm packet has been transferred.
    */
-  static const uint32_t CONFIG_END = 0x0;
+  static constexpr uint32_t CONFIG_END = 0x0;
 
   /**
    * Writing to this offset within the memory space of a virtual channel will insert data for
@@ -79,7 +84,7 @@ class PapbVcInterface : public VirtualChannelIF {
   std::string uioFile;
   int mapNum = 0;
 
-  uint32_t* vcBaseReg = nullptr;
+  volatile uint32_t* vcBaseReg = nullptr;
 
   uint32_t vcOffset = 0;
 
@@ -89,11 +94,13 @@ class PapbVcInterface : public VirtualChannelIF {
    */
   void startPacketTransfer();
 
+  void abortPacketTransfer();
+
   /**
    * @brief   This function sends the config byte to the virtual channel interface of the PTME
    *          IP Core to signal the end of a  packet transfer.
    */
-  void endPacketTransfer();
+  void completePacketTransfer();
 
   /**
    * @brief   This function reads the papb busy signal indicating whether the virtual channel