1 files changed, 120 insertions, 0 deletions
diff --git a/src/generic/serial_irq.c b/src/generic/serial_irq.c
new file mode 100644
index 00000000..79eaad7f
--- /dev/null
+++ b/src/generic/serial_irq.c
@@ -0,0 +1,120 @@
+// Generic interrupt based serial uart helper code
+//
+// Copyright (C) 2016-2018  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include <string.h> // memmove
+#include "autoconf.h" // CONFIG_SERIAL_BAUD
+#include "board/io.h" // readb
+#include "board/irq.h" // irq_save
+#include "board/misc.h" // console_sendf
+#include "board/pgm.h" // READP
+#include "command.h" // DECL_CONSTANT
+#include "sched.h" // sched_wake_tasks
+#include "serial_irq.h" // serial_enable_tx_irq
+
+static char receive_buf[192];
+static uint8_t receive_pos;
+static char transmit_buf[96];
+static uint8_t transmit_pos, transmit_max;
+
+DECL_CONSTANT(SERIAL_BAUD, CONFIG_SERIAL_BAUD);
+
+// Rx interrupt - store read data
+void
+serial_rx_byte(uint_fast8_t data)
+{
+    if (data == MESSAGE_SYNC)
+        sched_wake_tasks();
+    if (receive_pos >= sizeof(receive_buf))
+        // Serial overflow - ignore it as crc error will force retransmit
+        return;
+    receive_buf[receive_pos++] = data;
+}
+
+// Tx interrupt - get next byte to transmit
+int
+serial_get_tx_byte(uint8_t *pdata)
+{
+    if (transmit_pos >= transmit_max)
+        return -1;
+    *pdata = transmit_buf[transmit_pos++];
+    return 0;
+}
+
+// Remove from the receive buffer the given number of bytes
+static void
+console_pop_input(uint_fast8_t len)
+{
+    uint_fast8_t copied = 0;
+    for (;;) {
+        uint_fast8_t rpos = readb(&receive_pos);
+        uint_fast8_t needcopy = rpos - len;
+        if (needcopy) {
+            memmove(&receive_buf[copied], &receive_buf[copied + len]
+                    , needcopy - copied);
+            copied = needcopy;
+            sched_wake_tasks();
+        }
+        irqstatus_t flag = irq_save();
+        if (rpos != readb(&receive_pos)) {
+            // Raced with irq handler - retry
+            irq_restore(flag);
+            continue;
+        }
+        receive_pos = needcopy;
+        irq_restore(flag);
+        break;
+    }
+}
+
+// Process any incoming commands
+void
+console_task(void)
+{
+    uint_fast8_t rpos = readb(&receive_pos);
+    uint8_t pop_count;
+    int8_t ret = command_find_block(receive_buf, rpos, &pop_count);
+    if (ret > 0)
+        command_dispatch(receive_buf, pop_count);
+    if (ret)
+        console_pop_input(pop_count);
+}
+DECL_TASK(console_task);
+
+// Encode and transmit a "response" message
+void
+console_sendf(const struct command_encoder *ce, va_list args)
+{
+    // Verify space for message
+    uint_fast8_t tpos = readb(&transmit_pos), tmax = readb(&transmit_max);
+    if (tpos >= tmax) {
+        tpos = tmax = 0;
+        writeb(&transmit_max, 0);
+        writeb(&transmit_pos, 0);
+    }
+    uint_fast8_t max_size = READP(ce->max_size);
+    if (tmax + max_size > sizeof(transmit_buf)) {
+        if (tmax + max_size - tpos > sizeof(transmit_buf))
+            // Not enough space for message
+            return;
+        // Disable TX irq and move buffer
+        writeb(&transmit_max, 0);
+        tpos = readb(&transmit_pos);
+        tmax -= tpos;
+        memmove(&transmit_buf[0], &transmit_buf[tpos], tmax);
+        writeb(&transmit_pos, 0);
+        writeb(&transmit_max, tmax);
+        serial_enable_tx_irq();
+    }
+
+    // Generate message
+    char *buf = &transmit_buf[tmax];
+    uint8_t msglen = command_encodef(buf, ce, args);
+    command_add_frame(buf, msglen);
+
+    // Start message transmit
+    writeb(&transmit_max, tmax + msglen);
+    serial_enable_tx_irq();
+}