more correct head/tail ptr implementation

corundum_bm/corundum_bm.cc

@@ -19,7 +19,9 @@ static void eth_send(void *data, size_t len);
 namespace corundum {
 
 DescRing::DescRing()
-    : active(false)
+    : _dmaAddr(0), _sizeLog(0), _size(0), _sizeMask(0),
+    _index(0), _headPtr(0), _tailPtr(0), _currTail(0),
+    active(false)
 {
 }
 
@@ -46,13 +48,13 @@ DescRing::index()
     return this->_index;
 }
 
-unsigned
+ptr_t
 DescRing::headPtr()
 {
     return this->_headPtr;
 }
 
-unsigned
+ptr_t
 DescRing::tailPtr()
 {
     return this->_tailPtr;
@@ -94,13 +96,13 @@ DescRing::setIndex(unsigned index)
 }
 
 void
-DescRing::setHeadPtr(unsigned ptr)
+DescRing::setHeadPtr(ptr_t ptr)
 {
     this->_headPtr = ptr;
 }
 
 void
-DescRing::setTailPtr(unsigned ptr)
+DescRing::setTailPtr(ptr_t ptr)
 {
     this->_tailPtr = ptr;
 }
@@ -126,11 +128,11 @@ TxRing::~TxRing()
 }
 
 void
-TxRing::setHeadPtr(unsigned ptr)
+TxRing::setHeadPtr(ptr_t ptr)
 {
     DescRing::setHeadPtr(ptr);
-    if (!empty()) {
-        unsigned index = (this->_headPtr - 1) & this->_sizeMask;
+    while (this->_currTail != this->_headPtr) {
+        unsigned index = this->_currTail & this->_sizeMask;
         addr_t dma_addr = this->_dmaAddr + index * DESC_SIZE;
         /* Issue DMA read */
         DMAOp *op = new DMAOp;
@@ -138,9 +140,10 @@ TxRing::setHeadPtr(unsigned ptr)
         op->dma_addr = dma_addr;
         op->len = DESC_SIZE;
         op->ring = this;
-        op->tag = this->_headPtr;
+        op->tag = this->_currTail;
         op->write = false;
         issue_dma_op(op);
+        this->_currTail++;
     }
 }
 
@@ -161,7 +164,8 @@ TxRing::dmaDone(DMAOp *op)
     case DMA_TYPE_MEM:
         eth_send(op->data, op->len);
         // TODO: assume in order transmission
-        this->_tailPtr = (unsigned)op->tag;
+        assert(this->_tailPtr == op->tag);
+        this->_tailPtr++;
         delete op;
         break;
     default:
@@ -307,7 +311,6 @@ Port::queueDisable()
     this->_queueEnable = false;
 }
 
-void queueDisable();
 Corundum::Corundum()
 {
     this->port.setId(0);

corundum_bm/corundum_bm.h

@@ -4,6 +4,7 @@
 
 typedef uint32_t reg_t;
 typedef uint64_t addr_t;
+typedef uint16_t ptr_t;
 
 #define REG_FW_ID                   0x0000
 #define REG_FW_VER                  0x0004
@@ -94,7 +95,6 @@ namespace corundum {
 
 #define DESC_SIZE 16
 #define MAX_DMA_LEN 2048
-#define HW_PTR_MASK 0xFFFF
 
 class DescRing;
 
@@ -127,15 +127,15 @@ public:
     addr_t dmaAddr();
     size_t sizeLog();
     unsigned index();
-    unsigned headPtr();
-    unsigned tailPtr();
+    ptr_t headPtr();
+    ptr_t tailPtr();
 
     void setDMALower(uint32_t addr);
     void setDMAUpper(uint32_t addr);
     void setSizeLog(size_t size_log);
     void setIndex(unsigned index);
-    virtual void setHeadPtr(unsigned ptr);
-    void setTailPtr(unsigned ptr);
+    virtual void setHeadPtr(ptr_t ptr);
+    void setTailPtr(ptr_t ptr);
 
     virtual void dmaDone(DMAOp *op);
 
@@ -147,8 +147,9 @@ protected:
     size_t _size;
     size_t _sizeMask;
     unsigned _index;
-    unsigned _headPtr;
-    unsigned _tailPtr;
+    ptr_t _headPtr;
+    ptr_t _tailPtr;
+    ptr_t _currTail;
     bool active;
 };
 
@@ -157,7 +158,7 @@ public:
     TxRing();
     ~TxRing();
 
-    virtual void setHeadPtr(unsigned ptr) override;
+    virtual void setHeadPtr(ptr_t ptr) override;
     virtual void dmaDone(DMAOp *op) override;
 };