OpenOCD does a dmi read and gets dummy value back.

1 files changed, 93 insertions, 7 deletions

diff --git a/riscv/jtag_dtm.cc b/riscv/jtag_dtm.cc
index c099e33..5fcc303 100644
--- a/riscv/jtag_dtm.cc
+++ b/riscv/jtag_dtm.cc
@@ -1,6 +1,8 @@
 #include <stdio.h>
 
+#include "decode.h"
 #include "jtag_dtm.h"
+#include "debug_module.h"
 
 #if 1
 #  define D(x) x
@@ -8,7 +10,64 @@
 #  define D(x)
 #endif
 
+enum {
+  IR_IDCODE=1,
+  IR_DTMCONTROL=0x10,
+  IR_DBUS=0x11
+};
+
+#define DTMCONTROL_VERSION      0xf
+#define DTMCONTROL_ABITS        (0x3f << 4)
+#define DTMCONTROL_DBUSSTAT     (3<<10)
+#define DTMCONTROL_IDLE         (7<<12)
+#define DTMCONTROL_DBUSRESET    (1<<16)
+
+#define DBUS_OP                 3
+#define DBUS_DATA               (0xffffffffL<<2)
+#define DBUS_ADDRESS            ((1L<<(abits+34)) - (1L<<34))
+
+#define DBUS_OP_STATUS_SUCCESS	0
+#define DBUS_OP_STATUS_RESERVED	1
+#define DBUS_OP_STATUS_FAILED	2
+#define DBUS_OP_STATUS_BUSY	3
+
+#define DBUS_OP_NOP	        0
+#define DBUS_OP_READ	        1
+#define DBUS_OP_READ_WRITE	2
+#define DBUS_OP_RESERVED	3
+
+jtag_dtm_t::jtag_dtm_t(debug_module_t *dm) :
+  dm(dm),
+  dtmcontrol((abits << 4) | 1),
+  dbus(0),
+  state(TEST_LOGIC_RESET)
+{
+}
+
+void jtag_dtm_t::reset() {
+  state = TEST_LOGIC_RESET;
+}
+
 void jtag_dtm_t::set_pins(bool tck, bool tms, bool tdi) {
+  const jtag_state_t next[16][2] = {
+    /* TEST_LOGIC_RESET */    { RUN_TEST_IDLE, TEST_LOGIC_RESET },
+    /* RUN_TEST_IDLE */       { RUN_TEST_IDLE, SELECT_DR_SCAN },
+    /* SELECT_DR_SCAN */      { CAPTURE_DR, SELECT_IR_SCAN },
+    /* CAPTURE_DR */          { SHIFT_DR, EXIT1_DR },
+    /* SHIFT_DR */            { SHIFT_DR, EXIT1_DR },
+    /* EXIT1_DR */            { PAUSE_DR, UPDATE_DR },
+    /* PAUSE_DR */            { PAUSE_DR, EXIT2_DR },
+    /* EXIT2_DR */            { SHIFT_DR, UPDATE_DR },
+    /* UPDATE_DR */           { RUN_TEST_IDLE, SELECT_DR_SCAN },
+    /* SELECT_IR_SCAN */      { CAPTURE_IR, TEST_LOGIC_RESET },
+    /* CAPTURE_IR */          { SHIFT_IR, EXIT1_IR },
+    /* SHIFT_IR */            { SHIFT_IR, EXIT1_IR },
+    /* EXIT1_IR */            { PAUSE_IR, UPDATE_IR },
+    /* PAUSE_IR */            { PAUSE_IR, EXIT2_IR },
+    /* EXIT2_IR */            { SHIFT_IR, UPDATE_IR },
+    /* UPDATE_IR */           { RUN_TEST_IDLE, SELECT_DR_SCAN }
+  };
+
   if (!_tck && tck) {
     // Positive clock edge.
 
@@ -27,7 +86,7 @@ void jtag_dtm_t::set_pins(bool tck, bool tms, bool tdi) {
     state = next[state][_tms];
     switch (state) {
       case TEST_LOGIC_RESET:
-        ir = idcode_ir;
+        ir = IR_IDCODE;
         break;
       case CAPTURE_DR:
         capture_dr();
@@ -50,24 +109,29 @@ void jtag_dtm_t::set_pins(bool tck, bool tms, bool tdi) {
     }
   }
 
+  D(fprintf(stderr, "state=%2d, tdi=%d, tdo=%d, tms=%d, tck=%d, ir=0x%02x, dr=0x%lx\n",
+        state, _tdi, _tdo, _tms, _tck, ir, dr));
+
   _tck = tck;
   _tms = tms;
   _tdi = tdi;
-
-  D(fprintf(stderr, "state=%2d tck=%d tms=%d tdi=%d tdo=%d ir=0x%x dr=0x%lx\n",
-        state, _tck, _tms, _tdi, _tdo, ir, dr));
 }
 
 void jtag_dtm_t::capture_dr()
 {
   switch (ir) {
-    case idcode_ir:
-      dr = 0xdeadbeef;
+    case IR_IDCODE:
+      dr = idcode;
       dr_length = 32;
       break;
-    case dtmcontrol_ir:
+    case IR_DTMCONTROL:
       dr = dtmcontrol;
       dr_length = 32;
+      break;
+    case IR_DBUS:
+      dr = dbus;
+      dr_length = abits + 34;
+      break;
     default:
       D(fprintf(stderr, "Unsupported IR: 0x%x\n", ir));
       break;
@@ -78,4 +142,26 @@ void jtag_dtm_t::capture_dr()
 
 void jtag_dtm_t::update_dr()
 {
+  D(fprintf(stderr, "Update DR; IR=0x%x, DR=0x%lx (%d bits)\n",
+        ir, dr, dr_length));
+  switch (ir) {
+    case IR_DBUS:
+      {
+        unsigned op = get_field(dr, DBUS_OP);
+        uint32_t data = get_field(dr, DBUS_DATA);
+        unsigned address = get_field(dr, DBUS_ADDRESS);
+
+        dbus = dr;
+
+        if (op == DBUS_OP_READ || op == DBUS_OP_READ_WRITE) {
+          dbus = set_field(dbus, DBUS_DATA, dm->dmi_read(address));
+        }
+        if (op == DBUS_OP_READ_WRITE) {
+          dm->dmi_write(address, data);
+        }
+
+        dbus = set_field(dbus, DBUS_OP, DBUS_OP_STATUS_SUCCESS);
+      }
+      break;
+  }
 }