OpenOCD connects, and sends some data that we receive.

1 files changed, 70 insertions, 0 deletions

diff --git a/riscv/remote_bitbang.h b/riscv/remote_bitbang.h
new file mode 100644
index 0000000..165cc40
--- /dev/null
+++ b/riscv/remote_bitbang.h
@@ -0,0 +1,70 @@
+#ifndef REMOTE_BITBANG_H
+#define REMOTE_BITBANG_H
+
+#include <stdint.h>
+
+class sim_t;
+
+template <typename T>
+class circular_buffer_t
+{
+public:
+  // The buffer can store capacity-1 data elements.
+  circular_buffer_t(unsigned int capacity) : data(new T[capacity]),
+      start(0), end(0), capacity(capacity) {}
+  circular_buffer_t() : start(0), end(0), capacity(0) {}
+  ~circular_buffer_t() { delete[] data; }
+
+  T *data;
+  unsigned int start;   // Data start, inclusive.
+  unsigned int end;     // Data end, exclusive.
+  unsigned int capacity;    // Size of the buffer.
+  unsigned int size() const;
+  bool empty() const { return start == end; }
+  bool full() const { return ((end+1) % capacity) == start; }
+  T entry(unsigned index) { return data[(start + index) % capacity]; }
+
+  // Return size and address of the block of RAM where more data can be copied
+  // to be added to the buffer.
+  unsigned int contiguous_empty_size() const;
+  T *contiguous_empty() { return data + end; }
+  void data_added(unsigned int bytes);
+
+  unsigned int contiguous_data_size() const;
+  T *contiguous_data() { return data + start; }
+  // Tell the buffer that some bytes were consumed from the start of the
+  // buffer.
+  void consume(unsigned int bytes);
+
+  void reset();
+
+  T operator[](unsigned int i) const { return data[(start + i) % capacity]; }
+
+  void append(const T *src, unsigned int count);
+};
+
+class remote_bitbang_t
+{
+public:
+  // Create a new server, listening for connections from localhost on the given
+  // port.
+  remote_bitbang_t(uint16_t port, sim_t *sim);
+
+  // Do a bit of work.
+  void tick();
+
+private:
+  int socket_fd;
+  int client_fd;
+  circular_buffer_t<uint8_t> recv_buf;
+  circular_buffer_t<uint8_t> send_buf;
+
+  // Check for a client connecting, and accept if there is one.
+  void accept();
+  // Read as much into recv_buf as possible.
+  void read();
+  // Write as much of send_buf as possible.
+  void write();
+};
+
+#endif