documentation

README.md

@@ -27,6 +27,7 @@ Brief description of the modules:
 * Simulator: Top-level entity that builds & starts the simulation
 * BusCtrl: Simple bus manager
 * Trace: Simple trace peripheral
+* Timer: Simple IRQ programable real-time counter peripheral
 
 Helper classes:
 * Performance: Performance indicators stores here (singleton class)
@@ -90,9 +91,9 @@ In the asm directory there are some basic assembly examples.
 I "compile" one file with the follwing command:
 ```
 $ cd asm
-$ riscv32-unknown-linux-gnu-as  EternalLoop.asm -o EternalLoop.o
-$ riscv32-unknown-linux-gnu-ld -T ../my_linker_script.ld EternalLoop.o -o EternalLoop.elf
-$ objcopy -O ihex EternalLoop.elf EternalLoop.hex
+$ riscv32-unknown-elf-as  EternalLoop.asm -o EternalLoop.o
+$ riscv32-unknown-elf-ld -T ../my_linker_script.ld EternalLoop.o -o EternalLoop.elf
+$ riscv32-unknown-elf-objcopy -O ihex EternalLoop.elf EternalLoop.hex
 $ cd ..
 $ ./RISCV_SCTLM asm/EternalLoop.hex
 ```

inc/Timer.h

@@ -36,19 +36,36 @@ public:
     tlm_utils::simple_target_socket<Timer> socket;
     sc_out<bool> timer_irq;
 
-    // Constructor
+    /**
+     *
+     * @brief Constructor
+     * @param name module name
+     */
     Timer(sc_module_name name);
 
+    /**
+     * @brief Waits for event timer_event and triggers an IRQ
+     *
+     * Waits for event timer_event and triggers an IRQ (if it is not already
+     * triggered).
+     * After that, it posts the timer_event to 20 ns in the future to clear the IRQ
+     * line.
+     *
+     */
     void run();
 
-    // TLM-2 blocking transport method
+    /**
+     *
+     * @brief TLM-2.0 socket implementaiton
+     * @param trans TLM-2.0 transaction
+     * @param delay transactino delay time
+     */
     virtual void b_transport( tlm::tlm_generic_payload& trans, sc_time& delay );
 
 private:
-  sc_uint<64> m_mtime;
-  sc_uint<64> m_mtimecmp;
-  sc_event timer_event;
-  bool irq_value;
+  sc_uint<64> m_mtime;        /**< mtime register */
+  sc_uint<64> m_mtimecmp;     /**< mtimecmp register */
+  sc_event timer_event;       /**< event */
 };
 
 #endif

src/Timer.cpp

@@ -2,22 +2,16 @@
 
 SC_HAS_PROCESS(Timer);
 Timer::Timer(sc_module_name name): sc_module(name)
-  ,socket("timer_socket"), m_mtime(0), m_mtimecmp(0), irq_value(false) {
+  ,socket("timer_socket"), m_mtime(0), m_mtimecmp(0) {
 
     socket.register_b_transport(this, &Timer::b_transport);
 
     SC_THREAD(run);
   }
 
-/**
- * @brief Waits for event timer_event and triggers an IRQ
- *
- */
 void Timer::run() {
   while(true) {
 
-    // timer_event.notify( sc_time(10000, SC_NS) );
-
     wait(timer_event);
 
     if (timer_irq.read() == true) {
@@ -32,12 +26,6 @@ void Timer::run() {
   }
 }
 
-/**
- *
- * @brief TLM-2.0 socket implementaiton
- * @param trans TLM-2.0 transaction
- * @param delay transactino delay time
- */
 void Timer::b_transport( tlm::tlm_generic_payload& trans, sc_time& delay ) {
     tlm::tlm_command cmd = trans.get_command();
     sc_dt::uint64    addr = trans.get_address();
@@ -66,9 +54,6 @@ void Timer::b_transport( tlm::tlm_generic_payload& trans, sc_time& delay ) {
             m_mtimecmp.range(63,32) = aux_value;
             // notify needs relative time, mtimecmp works in absolute time
             notify_time = m_mtimecmp  - m_mtime;
-            // cout << "time: " << sc_core::sc_time_stamp()
-            //     << ": interrupt will be in " << dec << notify_time
-            //     << " ns" << endl;
             timer_event.notify( sc_time(notify_time, SC_NS) );
             break;
       }