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-rw-r--r--firmware/microblaze/lib/dbsm.c297
1 files changed, 297 insertions, 0 deletions
diff --git a/firmware/microblaze/lib/dbsm.c b/firmware/microblaze/lib/dbsm.c
new file mode 100644
index 000000000..9d66ec39c
--- /dev/null
+++ b/firmware/microblaze/lib/dbsm.c
@@ -0,0 +1,297 @@
+/* -*- 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 <stdbool.h>
+#include "nonstdio.h"
+#include <stdlib.h>
+
+typedef enum {
+ BS_EMPTY,
+ BS_FILLING,
+ BS_FULL,
+ BS_EMPTYING,
+} buffer_state_t;
+
+static 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;
+ sm->last_line_adj = 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;
+
+ 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
+ sr_tx_ctrl->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);
+ sr_tx_ctrl->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);
+ sr_tx_ctrl->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)
+{
+ sr_rx_ctrl->clear_overrun = 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)
+ ;
+ }
+}
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