mpm: Factor out user EEPROM code into own module

Affects Magnesium and Rhodium classes, which where duplicating this
code.

1 files changed, 142 insertions, 0 deletions

diff --git a/mpm/python/usrp_mpm/user_eeprom.py b/mpm/python/usrp_mpm/user_eeprom.py
new file mode 100644
index 000000000..513ba1520
--- /dev/null
+++ b/mpm/python/usrp_mpm/user_eeprom.py
@@ -0,0 +1,142 @@
+#
+# Copyright 2018 Ettus Research, a National Instruments Company
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+"""
+User EEPROM via Bfrfs mixin class
+"""
+
+import threading
+from six import iterkeys, iteritems
+from usrp_mpm.mpmlog import get_logger
+from usrp_mpm.sys_utils.udev import get_eeprom_paths
+from usrp_mpm.bfrfs import BufferFS
+
+DEFAULT_EEPROM_BLOCK_SIZE = 1024 # bytes
+
+def _get_user_eeprom_info(rev, user_eeprom_map):
+    """
+    Return an EEPROM access map based on the rev. It picks an entry from
+    user_eeprom_map that matches the rev.
+    """
+    rev_for_lookup = rev
+    while rev_for_lookup not in user_eeprom_map:
+        if rev_for_lookup < 0:
+            raise RuntimeError("Could not find a user EEPROM map for "
+                               "revision %d!", rev)
+        rev_for_lookup -= 1
+    assert rev_for_lookup in user_eeprom_map, \
+            "Invalid EEPROM lookup rev!"
+    return user_eeprom_map[rev_for_lookup]
+
+
+class BfrfsEEPROM(object):
+    """
+    Mixin class to give classes user-EEPROM capabilities.
+    """
+    # This map describes how the user data is stored in EEPROM. If a dboard rev
+    # changes the way the EEPROM is used, we add a new entry. If a dboard rev
+    # is not found in the map, then we go backward until we find a suitable rev
+    user_eeprom = {}
+    # Note: the attributes are created by derived class (the class we are mixing
+    #       into), so all logs in the BfrfsEEPROM class will be under the
+    #       derived class's category, etc.
+    log = None
+    rev = None
+    slot_idx = None
+
+
+    def __init__(self):
+        # Sanity check on the attributes. These need to be set properly by the
+        # parent class.
+        assert self.user_eeprom
+        assert self.log is not None
+        assert self.rev is not None
+        assert self.slot_idx is not None
+        self.eeprom_fs, self.eeprom_path = self._init_user_eeprom(
+            _get_user_eeprom_info(self.rev, self.user_eeprom)
+        )
+
+
+    def _init_user_eeprom(self, eeprom_info):
+        """
+        Reads out user-data EEPROM, and intializes a BufferFS object from that.
+        """
+        self.log.trace("Initializing EEPROM user data...")
+        eeprom_paths = get_eeprom_paths(eeprom_info.get('label'))
+        self.log.trace("Found the following EEPROM paths: `{}'".format(
+            eeprom_paths))
+        eeprom_path = eeprom_paths[self.slot_idx]
+        self.log.trace("Selected EEPROM path: `{}'".format(eeprom_path))
+        user_eeprom_offset = eeprom_info.get('offset', 0)
+        self.log.trace("Selected EEPROM offset: %d", user_eeprom_offset)
+        user_eeprom_data = open(eeprom_path, 'rb').read()[user_eeprom_offset:]
+        self.log.trace("Total EEPROM size is: %d bytes", len(user_eeprom_data))
+        return BufferFS(
+            user_eeprom_data,
+            max_size=eeprom_info.get('max_size'),
+            alignment=eeprom_info.get('alignment', DEFAULT_EEPROM_BLOCK_SIZE),
+            log=self.log
+        ), eeprom_path
+
+    def get_user_eeprom_data(self):
+        """
+        Return a dict of blobs stored in the user data section of the EEPROM.
+        """
+        return {
+            blob_id: self.eeprom_fs.get_blob(blob_id)
+            for blob_id in iterkeys(self.eeprom_fs.entries)
+        }
+
+    def set_user_eeprom_data(self, eeprom_data):
+        """
+        Update the local EEPROM with the data from eeprom_data.
+
+        The actual writing to EEPROM can take some time, and is thus kicked
+        into a background task. Don't call set_user_eeprom_data() quickly in
+        succession. Also, while the background task is running, reading the
+        EEPROM is unavailable and MPM won't be able to reboot until it's
+        completed.
+        However, get_user_eeprom_data() will immediately return the correct
+        data after this method returns.
+        """
+        for blob_id, blob in iteritems(eeprom_data):
+            self.eeprom_fs.set_blob(blob_id, blob)
+        self.log.trace("Writing EEPROM info to `{}'".format(self.eeprom_path))
+        eeprom_offset = _get_user_eeprom_info(self.rev, self.user_eeprom)['offset']
+        def _write_to_eeprom_task(path, offset, data, log):
+            " Writer task: Actually write to file "
+            # Note: This can be sped up by only writing sectors that actually
+            # changed. To do so, this function would need to read out the
+            # current state of the file, do some kind of diff, and then seek()
+            # to the different sectors. When very large blobs are being
+            # written, it doesn't actually help all that much, of course,
+            # because in that case, we'd anyway be changing most of the EEPROM.
+            with open(path, 'r+b') as eeprom_file:
+                log.trace("Seeking forward to `{}'".format(offset))
+                eeprom_file.seek(eeprom_offset)
+                log.trace("Writing a total of {} bytes.".format(
+                    len(self.eeprom_fs.buffer)))
+                eeprom_file.write(data)
+                log.trace("EEPROM write complete.")
+        thread_id = "eeprom_writer_task_{}".format(self.slot_idx)
+        if any([x.name == thread_id for x in threading.enumerate()]):
+            # Should this be fatal?
+            self.log.warn("Another EEPROM writer thread is already active!")
+        writer_task = threading.Thread(
+            target=_write_to_eeprom_task,
+            args=(
+                self.eeprom_path,
+                eeprom_offset,
+                self.eeprom_fs.buffer,
+                self.log
+            ),
+            name=thread_id,
+        )
+        writer_task.start()
+        # Now return and let the copy finish on its own. The thread will detach
+        # and MPM won't terminate this process until the thread is complete.
+        # This does not stop anyone from killing this process (and the thread)
+        # while the EEPROM write is happening, though.
+        #