Adding support for U-Boot booting in Juno.

wlauto/utils/uboot.py

@@ -0,0 +1,116 @@
+
+#    Copyright 2014-2015 ARM Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+import re
+import time
+import logging
+
+from wlauto.utils.serial_port import TIMEOUT
+
+
+logger = logging.getLogger('U-Boot')
+
+
+class UbootMenu(object):
+    """
+    Allows navigating Das U-boot menu over serial (it relies on a pexpect connection).
+
+    """
+
+    option_regex = re.compile(r'^\[(\d+)\]\s+([^\r]+)\r\n', re.M)
+    prompt_regex = re.compile(r'^([^\r\n]+):\s*', re.M)
+    invalid_regex = re.compile(r'Invalid input \(max (\d+)\)', re.M)
+
+    load_delay = 1  # seconds
+    default_timeout = 60  # seconds
+
+    def __init__(self, conn, start_prompt='Hit any key to stop autoboot'):
+        """
+        :param conn: A serial connection as returned by ``pexect.spawn()``.
+        :param prompt: U-Boot menu prompt
+        :param start_prompt: The starting prompt to wait for during ``open()``.
+
+        """
+        self.conn = conn
+        self.conn.crlf = '\n\r'  # TODO: this has *got* to be a bug in U-Boot...
+        self.start_prompt = start_prompt
+        self.options = {}
+        self.prompt = None
+
+    def open(self, timeout=default_timeout):
+        """
+        "Open" the UEFI menu by sending an interrupt on STDIN after seeing the
+        starting prompt (configurable upon creation of the ``UefiMenu`` object.
+
+        """
+        self.conn.expect(self.start_prompt, timeout)
+        self.conn.sendline('')
+        time.sleep(self.load_delay)
+        self.conn.readline()  # garbage
+        self.conn.sendline('')
+        self.prompt = self.conn.readline().strip()
+
+    def getenv(self):
+        output = self.enter('printenv')
+        result = {}
+        for line in output.split('\n'):
+            if '=' in line:
+                variable, value = line.split('=', 1)
+                result[variable.strip()] = value.strip()
+        return result
+
+    def setenv(self, variable, value, force=False):
+        force_str = ' -f' if force else ''
+        if value is not None:
+            command = 'setenv{} {} {}'.format(force_str, variable, value)
+        else:
+            command = 'setenv{} {}'.format(force_str, variable)
+        return self.enter(command)
+
+    def boot(self):
+        self.write_characters('boot')
+
+    def nudge(self):
+        """Send a little nudge to ensure there is something to read. This is useful when you're not
+        sure if all out put from the serial has been read already."""
+        self.enter('')
+
+    def enter(self, value, delay=load_delay):
+        """Like ``select()`` except no resolution is performed -- the value is sent directly
+        to the serial connection."""
+        # Empty the buffer first, so that only response to the input about to
+        # be sent will be processed by subsequent commands.
+        value = str(value)
+        self.empty_buffer()
+        self.write_characters(value)
+        self.conn.expect(self.prompt, timeout=delay)
+        return self.conn.before
+
+    def write_characters(self, line):
+        line = line.rstrip('\r\n')
+        for c in line:
+            self.conn.send(c)
+            time.sleep(0.05)
+        self.conn.sendline('')
+
+    def empty_buffer(self):
+        try:
+            while True:
+                time.sleep(0.1)
+                self.conn.read_nonblocking(size=1024, timeout=0.1)
+        except TIMEOUT:
+            pass
+        self.conn.buffer = ''
+