Refactor remote bitbang code.

1 files changed, 81 insertions, 0 deletions

diff --git a/riscv/jtag_dtm.h b/riscv/jtag_dtm.h
new file mode 100644
index 0000000..e425c8e
--- /dev/null
+++ b/riscv/jtag_dtm.h
@@ -0,0 +1,81 @@
+#ifndef JTAG_DTM_H
+#define JTAG_DTM_H
+
+#include <stdint.h>
+
+typedef enum {
+  TEST_LOGIC_RESET,
+  RUN_TEST_IDLE,
+  SELECT_DR_SCAN,
+  CAPTURE_DR,
+  SHIFT_DR,
+  EXIT1_DR,
+  PAUSE_DR,
+  EXIT2_DR,
+  UPDATE_DR,
+  SELECT_IR_SCAN,
+  CAPTURE_IR,
+  SHIFT_IR,
+  EXIT1_IR,
+  PAUSE_IR,
+  EXIT2_IR,
+  UPDATE_IR
+} jtag_state_t;
+
+class jtag_dtm_t
+{
+  static const unsigned idcode_ir = 1;
+  static const unsigned idcode_dr = 0xdeadbeef;
+  static const unsigned dtmcontrol_ir = 0x10;
+
+  public:
+    jtag_dtm_t() :
+      dtmcontrol(
+          (6 << 4) |        // abits
+          1                 // version
+          ),
+      state(TEST_LOGIC_RESET) {}
+
+    void reset() {
+      state = TEST_LOGIC_RESET;
+    }
+
+    void set_pins(bool tck, bool tms, bool tdi);
+
+    bool tdo() const { return _tdo; }
+
+  private:
+    bool _tck, _tms, _tdi, _tdo;
+    uint32_t ir;
+    const unsigned ir_length = 5;
+    uint64_t dr;
+    unsigned dr_length;
+
+    uint32_t dtmcontrol;
+
+    jtag_state_t state;
+
+    void capture_dr();
+    void update_dr();
+
+    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 }
+    };
+};
+
+#endif