rtio: raise input overflow exception

artiq/coredevice/runtime_exceptions.py

@@ -13,7 +13,8 @@ class OutOfMemory(RuntimeException):
 
 
 class RTIOUnderflow(RuntimeException):
-    """Raised when the CPU fails to submit a RTIO event early enough (with respect to the event's timestamp).
+    """Raised when the CPU fails to submit a RTIO event early enough
+    (with respect to the event's timestamp).
 
     """
     eid = 1
@@ -28,6 +29,14 @@ class RTIOSequenceError(RuntimeException):
     eid = 2
 
 
+class RTIOOverflow(RuntimeException):
+    """Raised when at least one event could not be registered into the RTIO
+    input FIFO because it was full (CPU not reading fast enough).
+
+    """
+    eid = 3
+
+
 exception_map = {e.eid: e for e in globals().values()
                  if inspect.isclass(e)
                  and issubclass(e, RuntimeException)

soc/runtime/exceptions.h

@@ -4,7 +4,8 @@
 enum {
 	EID_OUT_OF_MEMORY = 0,
 	EID_RTIO_UNDERFLOW = 1,
-	EID_RTIO_SEQUENCE_ERROR = 2
+	EID_RTIO_SEQUENCE_ERROR = 2,
+	EID_RTIO_OVERFLOW = 3,
 };
 
 int exception_setjmp(void *jb) __attribute__((returns_twice));

soc/runtime/rtio.c

@@ -59,6 +59,11 @@ long long int rtio_get(int channel)
 
     rtio_chan_sel_write(channel);
     while(rtio_i_readable_read() || (rtio_o_level_read() != 0)) {
+        if(rtio_i_overflow_read()) {
+            rtio_reset_logic_write(1);
+            rtio_reset_logic_write(0);
+            exception_raise(EID_RTIO_OVERFLOW);
+        }
         if(rtio_i_readable_read()) {
             r = rtio_i_timestamp_read();
             rtio_i_re_write(1);