mpm: Add mpmutils module, includes poll_with_timeout

This is a convenience function for polling with sleeps and timeouts.

2 files changed, 41 insertions, 2 deletions

diff --git a/mpm/python/usrp_mpm/CMakeLists.txt b/mpm/python/usrp_mpm/CMakeLists.txt
index a90844956..ba640f7cc 100644
--- a/mpm/python/usrp_mpm/CMakeLists.txt
+++ b/mpm/python/usrp_mpm/CMakeLists.txt
@@ -27,11 +27,12 @@ SET(USRP_MPM_TOP_FILES
     ${CMAKE_CURRENT_SOURCE_DIR}/dtoverlay.py
     ${CMAKE_CURRENT_SOURCE_DIR}/eeprom.py
     ${CMAKE_CURRENT_SOURCE_DIR}/mpmlog.py
+    ${CMAKE_CURRENT_SOURCE_DIR}/mpmtypes.py
+    ${CMAKE_CURRENT_SOURCE_DIR}/mpmutils.py
+    ${CMAKE_CURRENT_SOURCE_DIR}/net.py
     ${CMAKE_CURRENT_SOURCE_DIR}/nijesdcore.py
     ${CMAKE_CURRENT_SOURCE_DIR}/rpc_server.py
     ${CMAKE_CURRENT_SOURCE_DIR}/sysfs_gpio.py
-    ${CMAKE_CURRENT_SOURCE_DIR}/mpmtypes.py
-    ${CMAKE_CURRENT_SOURCE_DIR}/net.py
     ${CMAKE_CURRENT_SOURCE_DIR}/uio.py
 )
 LIST(APPEND USRP_MPM_FILES ${USRP_MPM_TOP_FILES})
diff --git a/mpm/python/usrp_mpm/mpmutils.py b/mpm/python/usrp_mpm/mpmutils.py
new file mode 100644
index 000000000..ad4457419
--- /dev/null
+++ b/mpm/python/usrp_mpm/mpmutils.py
@@ -0,0 +1,38 @@
+#
+# Copyright 2017 Ettus Research, National Instruments Company
+#
+# SPDX-License-Identifier: GPL-3.0
+#
+"""
+Miscellaneous utilities for MPM
+"""
+
+import time
+
+def poll_with_timeout(state_check, timeout_ms, interval_ms):
+    """
+    Calls state_check() every interval_ms until it returns a positive value, or
+    until a timeout is exceeded.
+
+    Returns True if state_check() returned True within the timeout.
+
+    Arguments:
+    state_check -- Functor that returns a Boolean success value, and takes no
+                   arguments.
+    timeout_ms -- The total timeout in milliseconds. state_check() has to
+                  return True within this time.
+    interval_ms -- Sleep time between calls to state_check(). Note that if
+                   interval_ms is larger than timeout_ms, state_check() will be
+                   called exactly once, and then poll_with_timeout() will still
+                   sleep for interval_ms milliseconds. Typically, interval_ms
+                   should be chosen much smaller than timeout_ms, but not too
+                   small for this to become a busy loop.
+    """
+    max_time = time.time() + (float(timeout_ms) / 1000)
+    interval_s = float(interval_ms) / 1000
+    while time.time() < max_time:
+        if state_check():
+            return True
+        time.sleep(interval_s)
+    return False
+