Added plic functionality

CMakeLists.txt

@@ -15,7 +15,7 @@ set(GIT_SUBMODULE_BRANCH_sc-components ${GIT_BRANCH})
 set(GIT_SUBMODULE_BRANCH_dbt-core ${GIT_BRANCH})
 
 include(GNUInstallDirs)
-include(cmake/Submodules.cmake)
+include(Submodules)
 
 #enable_testing() 
 
@@ -33,7 +33,7 @@ find_package(Threads)
 find_package(Tcmalloc)
 
 set(PROJECT_3PARTY_DIRS external sr_report sr_signal)
-include(sc-components/cmake/clang-format.cmake)
+include(clang-format)
 
 add_subdirectory(external)
 add_subdirectory(dbt-core)

riscv.sc/incl/sysc/SiFive/platform.h

@@ -59,6 +59,8 @@ public:
     scc::memory<128_kB, 32> i_mem_ram;
     sc_core::sc_signal<sc_core::sc_time> s_clk;
     sc_core::sc_signal<bool> s_rst, s_mtime_int, s_msie_int;
+    sc_core::sc_vector<sc_core::sc_signal<bool>> s_global_int;
+    sc_core::sc_signal<bool> s_core_int;
 
     platform(sc_core::sc_module_name nm);
 

riscv.sc/incl/sysc/SiFive/plic.h

@@ -17,7 +17,8 @@
 #ifndef _PLIC_H_
 #define _PLIC_H_
 
-#include "scc/tlm_target.h"
+#include <scc/register.h>
+#include <scc/tlm_target.h>
 
 namespace sysc {
 
@@ -28,14 +29,27 @@ public:
     SC_HAS_PROCESS(plic);
     sc_core::sc_in<sc_core::sc_time> clk_i;
     sc_core::sc_in<bool> rst_i;
+    sc_core::sc_vector<sc_core::sc_in<bool>> global_interrupts_i;
+    sc_core::sc_out<bool> core_interrupt_o;
+    sc_core::sc_event raise_int_ev;
+    sc_core::sc_event clear_int_ev;
     plic(sc_core::sc_module_name nm);
-    virtual ~plic() override;
+    ~plic() override;
 
 protected:
     void clock_cb();
     void reset_cb();
+    void init_callbacks();
+
+    void global_int_port_cb();
+    void handle_pending_int();
+    void reset_pending_int(uint32_t irq);
+
+    void raise_core_interrupt();
+    void clear_core_interrupt();
     sc_core::sc_time clk;
     std::unique_ptr<plic_regs> regs;
+    std::function<bool(scc::sc_register<uint32_t>, uint32_t)> m_claim_complete_write_cb;
 };
 
 } /* namespace sysc */

riscv.sc/src/sysc/platform.cpp

@@ -39,7 +39,9 @@ platform::platform(sc_core::sc_module_name nm)
 , NAMED(i_mem_qspi)
 , NAMED(i_mem_ram)
 , NAMED(s_clk)
-, NAMED(s_rst) {
+, NAMED(s_rst)
+, NAMED(s_global_int, 256)
+, NAMED(s_core_int) {
     i_core_complex.initiator(i_router.target[0]);
     size_t i = 0;
     for (const auto &e : e300_plat_map) {
@@ -75,6 +77,8 @@ platform::platform(sc_core::sc_module_name nm)
     i_clint.mtime_int_o(s_mtime_int);
     i_clint.msip_int_o(s_msie_int);
 
+    i_plic.global_interrupts_i(s_global_int);
+    i_plic.core_interrupt_o(s_core_int);
     SC_THREAD(gen_reset);
 }
 

riscv.sc/src/sysc/plic.cpp

@@ -14,10 +14,11 @@
 // the License.
 ////////////////////////////////////////////////////////////////////////////////
 
-#include "sysc/SiFive/plic.h"
+#include <sysc/SiFive/plic.h>
 
-#include "scc/utilities.h"
-#include "sysc/SiFive/gen/plic_regs.h"
+#include <scc/utilities.h>
+#include <scc/report.h>
+#include <sysc/SiFive/gen/plic_regs.h>
 
 namespace sysc {
 
@@ -26,8 +27,24 @@ plic::plic(sc_core::sc_module_name nm)
 , tlm_target<>(clk)
 , NAMED(clk_i)
 , NAMED(rst_i)
-, NAMEDD(plic_regs, regs) {
+, NAMED(global_interrupts_i, 256)
+, NAMED(core_interrupt_o)
+, NAMEDD(plic_regs, regs)
+
+{
     regs->registerResources(*this);
+    // register callbacks
+    init_callbacks();
+    regs->claim_complete.set_write_cb(m_claim_complete_write_cb);
+
+    // port callbacks
+    SC_METHOD(global_int_port_cb);
+    for (uint8_t i = 0; i < 255; i++) {
+        sensitive << global_interrupts_i[i].pos();
+    }
+    dont_initialize();
+
+    // register event callbacks
     SC_METHOD(clock_cb);
     sensitive << clk_i;
     SC_METHOD(reset_cb);
@@ -37,6 +54,16 @@ plic::plic(sc_core::sc_module_name nm)
 
 plic::~plic() {}
 
+void plic::init_callbacks() {
+    m_claim_complete_write_cb = [=](scc::sc_register<uint32_t> reg, uint32_t v) -> bool {
+        reg.put(v);
+        reset_pending_int(v);
+        // std::cout << "Value of register: 0x" << std::hex << reg << std::endl;
+        // todo: reset related interrupt and find next high-prio interrupt
+        return true;
+    };
+}
+
 void plic::clock_cb() { this->clk = clk_i.read(); }
 
 void plic::reset_cb() {
@@ -46,4 +73,86 @@ void plic::reset_cb() {
         regs->reset_stop();
 }
 
+// Functional handling of interrupts:
+// - global_int_port_cb()
+//   - set pending register bits
+//   - called by: incoming global_int
+// - handle_pending_int()
+//   - update claim register content
+//   - generate core-interrupt pulse
+//   - called by:
+//     - incoming global_int
+//     - complete-register write access
+// - reset_pending_int(int-id)
+//   - reset pending bit
+//   - call next handle_pending_int()
+//   - called by:
+//     - complete-reg write register content
+
+void plic::global_int_port_cb() {
+
+    // set related pending bit if enable is set for incoming global_interrupt
+
+    // todo: extend up to 255 bits (limited to 32 right now)
+    for (uint32_t i = 1; i < 32; i++) {
+        uint32_t enable_bits = regs->r_enabled;
+        bool enable = enable_bits & (0x1 << i); // read enable bit
+
+        if (enable && global_interrupts_i[i].read() == 1) {
+            regs->r_pending = regs->r_pending | (0x1 << i);
+            LOG(DEBUG) << "pending interrupt identified: " << i;
+        }
+    }
+
+    handle_pending_int();
+}
+
+void plic::handle_pending_int() {
+    // identify high-prio pending interrupt and raise a core-interrupt
+    uint32_t claim_int = 0;  // claim interrupt
+    uint32_t claim_prio = 0; // related priority (highest prio interrupt wins the race)
+    bool raise_int = 0;
+    uint32_t thold = regs->r_threshold.threshold; // threshold value
+
+    // todo: extend up to 255 bits (limited to 32 right now)
+    for (uint32_t i = 1; i < 32; i++) {
+        uint32_t pending_bits = regs->r_pending;
+        bool pending = (pending_bits & (0x1 << i)) ? true : false;
+        uint32_t prio = regs->r_priority[i - 1].priority; // read priority value
+
+        if (pending && thold < prio) {
+            regs->r_pending = regs->r_pending | (0x1 << i);
+            // below condition ensures implicitly that lowest id is selected in case of multiple identical
+            // priority-interrupts
+            if (prio > claim_prio) {
+                claim_prio = prio;
+                claim_int = i;
+                raise_int = 1;
+                LOG(DEBUG) << "pending interrupt activated: " << i;
+            }
+        }
+    }
+
+    if (raise_int) {
+        regs->r_claim_complete = claim_int;
+        core_interrupt_o.write(1);
+        // todo: evluate clock period
+    } else {
+        regs->r_claim_complete = 0;
+        LOG(DEBUG) << "no further pending interrupt.";
+    }
+}
+
+void plic::reset_pending_int(uint32_t irq) {
+    // todo: evaluate enable register (see spec)
+    // todo: make sure that pending is set, otherwise don't reset irq ... read spec.
+    LOG(INFO) << "reset pending interrupt: " << irq;
+    // reset related pending bit
+    regs->r_pending &= ~(0x1 << irq);
+    core_interrupt_o.write(0);
+
+    // evaluate next pending interrupt
+    handle_pending_int();
+}
+
 } /* namespace sysc */