1 files changed, 298 insertions, 0 deletions

diff --git a/usrp2/firmware/lib/dbsm.c b/usrp2/firmware/lib/dbsm.c
new file mode 100644
index 000000000..5e2042bed
--- /dev/null
+++ b/usrp2/firmware/lib/dbsm.c
@@ -0,0 +1,298 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2007,2008 Free Software Foundation, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Double Buffering State Machine
+ */
+
+#include "dbsm.h"
+#include "memory_map.h"
+#include "buffer_pool.h"
+#include "bool.h"
+#include "nonstdio.h"
+#include <stdlib.h>
+
+typedef enum {
+  BS_EMPTY,
+  BS_FILLING,
+  BS_FULL,
+  BS_EMPTYING,
+} buffer_state_t;
+
+buffer_state_t buffer_state[NBUFFERS];
+
+bool
+dbsm_nop_inspector(dbsm_t *sm, int buf_this)
+{
+  return false;
+}
+
+void
+dbsm_init(dbsm_t *sm, int buf0,
+	  const buf_cmd_args_t *recv, const buf_cmd_args_t *send,
+	  inspector_t inspect)
+{
+  if (buf0 & 0x1)	// must be even
+    abort();
+
+  sm->buf0 = buf0;
+  sm->running = false;
+  sm->recv_args = *recv;
+  sm->send_args = *send;
+
+  sm->rx_idle = true;
+  sm->tx_idle = true;
+
+  sm->inspect = inspect;
+
+  // How much to adjust the last_line register.
+  // It's 1 for everything but the ethernet.
+  sm->last_line_adj = recv->port == PORT_ETH ? 3 : 1;
+
+  buffer_state[sm->buf0] = BS_EMPTY;
+  buffer_state[sm->buf0 ^ 1] = BS_EMPTY;
+
+  sm->precomputed_receive_to_buf_ctrl_word[0] =
+    (BPC_READ
+     | BPC_BUFFER(sm->buf0)
+     | BPC_PORT(sm->recv_args.port)
+     | BPC_STEP(1)
+     | BPC_FIRST_LINE(sm->recv_args.first_line)
+     | BPC_LAST_LINE(sm->recv_args.last_line));
+    
+  sm->precomputed_receive_to_buf_ctrl_word[1] =
+    (BPC_READ
+     | BPC_BUFFER(sm->buf0 ^ 1)
+     | BPC_PORT(sm->recv_args.port)
+     | BPC_STEP(1)
+     | BPC_FIRST_LINE(sm->recv_args.first_line)
+     | BPC_LAST_LINE(sm->recv_args.last_line));
+    
+  sm->precomputed_send_from_buf_ctrl_word[0] =
+    (BPC_WRITE
+     | BPC_BUFFER(sm->buf0)
+     | BPC_PORT(sm->send_args.port)
+     | BPC_STEP(1)
+     | BPC_FIRST_LINE(sm->send_args.first_line)
+     | BPC_LAST_LINE(0));		// last line filled in at runtime
+    
+  sm->precomputed_send_from_buf_ctrl_word[1] =
+    (BPC_WRITE
+     | BPC_BUFFER(sm->buf0 ^ 1)
+     | BPC_PORT(sm->send_args.port)
+     | BPC_STEP(1)
+     | BPC_FIRST_LINE(sm->send_args.first_line)
+     | BPC_LAST_LINE(0));		// last line filled in at runtime
+    
+}
+
+static inline void
+dbsm_receive_to_buf(dbsm_t *sm, int bufno)
+{
+  buffer_pool_ctrl->ctrl = sm->precomputed_receive_to_buf_ctrl_word[bufno & 1];
+}
+
+static inline void
+dbsm_send_from_buf(dbsm_t *sm, int bufno)
+{
+  buffer_pool_ctrl->ctrl =
+    (sm->precomputed_send_from_buf_ctrl_word[bufno & 1]
+     | BPC_LAST_LINE(buffer_pool_status->last_line[bufno] - sm->last_line_adj));
+}
+
+void
+dbsm_start(dbsm_t *sm)
+{
+  // printf("dbsm_start: buf0 = %d, recv_port = %d\n", sm->buf0, sm->recv_args.port);
+
+  sm->running = true;
+
+  buffer_state[sm->buf0] = BS_EMPTY;
+  buffer_state[sm->buf0 ^ 1] = BS_EMPTY;
+
+  bp_clear_buf(sm->buf0);
+  bp_clear_buf(sm->buf0 ^ 1);
+
+  sm->tx_idle = true;
+  sm->rx_idle = false;
+  dbsm_receive_to_buf(sm, sm->buf0);
+  buffer_state[sm->buf0] = BS_FILLING;
+
+}
+
+
+void
+dbsm_stop(dbsm_t *sm)
+{
+  sm->running = false;
+  bp_clear_buf(sm->buf0);
+  bp_clear_buf(sm->buf0 ^ 1);
+  buffer_state[sm->buf0] = BS_EMPTY;
+  buffer_state[sm->buf0 ^ 1] = BS_EMPTY;
+}
+
+static void dbsm_process_helper(dbsm_t *sm, int buf_this);
+static void dbsm_error_helper(dbsm_t *sm, int buf_this);
+
+void
+dbsm_process_status(dbsm_t *sm, uint32_t status)
+{
+  if (!sm->running)
+    return;
+
+  if (status & (BPS_ERROR(sm->buf0) | BPS_ERROR(sm->buf0 ^ 1))){
+    putchar('E');
+    // Most likely an ethernet Rx error.  We just restart the transfer.
+    if (status & (BPS_ERROR(sm->buf0)))
+      dbsm_error_helper(sm, sm->buf0);
+
+    if (status & (BPS_ERROR(sm->buf0 ^ 1)))
+      dbsm_error_helper(sm, sm->buf0 ^ 1);
+  }
+
+  if (status & BPS_DONE(sm->buf0))
+    dbsm_process_helper(sm, sm->buf0);
+
+  if (status & BPS_DONE(sm->buf0 ^ 1))
+    dbsm_process_helper(sm, sm->buf0 ^ 1);
+}
+
+static void
+dbsm_process_helper(dbsm_t *sm, int buf_this)
+{
+  int buf_other = buf_this ^ 1;
+
+  if (1){
+    bp_clear_buf(buf_this);
+
+    if (buffer_state[buf_this] == BS_FILLING){
+      buffer_state[buf_this] = BS_FULL;
+      //
+      // does s/w handle this packet?
+      //
+      if (sm->inspect(sm, buf_this)){
+	// s/w handled the packet; refill the buffer
+	dbsm_receive_to_buf(sm, buf_this);
+	buffer_state[buf_this] = BS_FILLING;
+      }
+
+      else {	// s/w didn't handle this; pass it on
+
+	if(buffer_state[buf_other] == BS_EMPTY){
+	  dbsm_receive_to_buf(sm, buf_other);
+	  buffer_state[buf_other] = BS_FILLING;
+	}
+	else
+	  sm->rx_idle = true;
+
+	if (sm->tx_idle){
+	  sm->tx_idle = false;
+	  dbsm_send_from_buf(sm, buf_this);
+	  buffer_state[buf_this] = BS_EMPTYING;
+	}
+      }
+    }
+    else {  // buffer was emptying
+      buffer_state[buf_this] = BS_EMPTY;
+      if (sm->rx_idle){
+	sm->rx_idle = false;
+	dbsm_receive_to_buf(sm, buf_this);
+	buffer_state[buf_this] = BS_FILLING;
+      }
+      if (buffer_state[buf_other] == BS_FULL){
+	dbsm_send_from_buf(sm, buf_other);
+	buffer_state[buf_other] = BS_EMPTYING;
+      }
+      else
+	sm->tx_idle = true;
+    }
+  }
+}
+
+static void
+dbsm_error_helper(dbsm_t *sm, int buf_this)
+{
+  bp_clear_buf(buf_this);		// clears ERROR flag
+
+  if (buffer_state[buf_this] == BS_FILLING){
+    dbsm_receive_to_buf(sm, buf_this);	  // restart the xfer
+  }
+  else { // buffer was emptying
+    dbsm_send_from_buf(sm, buf_this);	  // restart the xfer
+  }
+}
+
+/*
+ * Handle DSP Tx underrun
+ */
+void
+dbsm_handle_tx_underrun(dbsm_t *sm)
+{
+  // clear the DSP Tx state machine
+  dsp_tx_regs->clear_state = 1;
+
+  // If there's a buffer that's empyting, clear it & flush xfer
+
+  if (buffer_state[sm->buf0] == BS_EMPTYING){
+    bp_clear_buf(sm->buf0);
+    dsp_tx_regs->clear_state = 1;	// flush partial packet
+    // drop frame in progress on ground.  Pretend it finished
+    dbsm_process_helper(sm, sm->buf0);
+  }
+  else if (buffer_state[sm->buf0 ^ 1] == BS_EMPTYING){
+    bp_clear_buf(sm->buf0 ^ 1);
+    dsp_tx_regs->clear_state = 1;	// flush partial packet
+    // drop frame in progress on ground.  Pretend it finished
+    dbsm_process_helper(sm, sm->buf0 ^ 1);
+  }
+}
+
+/*
+ * Handle DSP Rx overrun
+ */
+void
+dbsm_handle_rx_overrun(dbsm_t *sm)
+{
+  dsp_rx_regs->clear_state = 1;
+
+  // If there's a buffer that's filling, clear it.
+  // Any restart will be the job of the caller.
+  
+  if (buffer_state[sm->buf0] == BS_FILLING)
+    bp_clear_buf(sm->buf0);
+
+  if (buffer_state[sm->buf0 ^1] == BS_FILLING)
+    bp_clear_buf(sm->buf0 ^ 1);
+}
+
+void 
+dbsm_wait_for_opening(dbsm_t *sm)
+{
+  if (buffer_state[sm->buf0] == BS_EMPTYING){
+    // wait for xfer to complete
+    int mask = BPS_DONE(sm->buf0) | BPS_ERROR(sm->buf0) | BPS_IDLE(sm->buf0);
+    while ((buffer_pool_status->status & mask) == 0)
+      ;
+  }
+  else if (buffer_state[sm->buf0 ^ 1] == BS_EMPTYING){
+    // wait for xfer to complete
+    int mask = BPS_DONE(sm->buf0 ^ 1) | BPS_ERROR(sm->buf0 ^ 1) | BPS_IDLE(sm->buf0 ^ 1);
+    while ((buffer_pool_status->status & mask) == 0)
+      ;
+  }
+}