boards: up_squared_adsp: Add IPM terminal tool

Add tool which can access ADSP console over IPM using Python device
library and polling Doorbell registers.

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>

boards/xtensa/up_squared_adsp/tools/mbterm.py

@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2020 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+
+from time import sleep
+from mmap import mmap, ACCESS_COPY
+from ctypes import c_uint8
+
+from lib.device import Device
+import lib.registers as regs
+
+MBOX = 0x91281000
+LENGTH = 0x1000
+
+with open("/dev/mem", "rb") as f:
+    mem_map = mmap(f.fileno(), LENGTH, access=ACCESS_COPY, offset=MBOX)
+    mem = (c_uint8 * LENGTH).from_buffer(mem_map)
+
+def mailbox_poll_mem(dev):
+    while True:
+        if dev.dsp_hipct.value & regs.ADSP_IPC_HIPCT_BUSY:
+
+            # Use only id for passing character
+            line_len = dev.dsp_hipct.value & regs.ADSP_IPC_HIPCT_MSG
+
+            # Mask out internal bits
+            line_len &= 0x10FFFF
+
+            if line_len:
+                print(bytes(mem[:line_len]).decode())
+
+            # Clear interrupt
+            dev.dsp_hipct.value |= regs.ADSP_IPC_HIPCT_BUSY
+        else:
+            sleep(0.005)
+
+# Character passed in mailbox ID field
+def mailbox_poll_char(dev):
+    while True:
+        if dev.dsp_hipct.value & regs.ADSP_IPC_HIPCT_BUSY:
+
+            # Use only id for passing character
+            character = dev.dsp_hipct.value & regs.ADSP_IPC_HIPCT_MSG
+
+            # Get readable character
+            character &= 0x10FFFF
+
+            print('{}'.format(chr(character)), end='')
+
+            # Clear interrupt
+            dev.dsp_hipct.value |= regs.ADSP_IPC_HIPCT_BUSY
+        else:
+            sleep(0.005)
+
+
+if __name__ == "__main__":
+    # Clear Done if needed
+    #dev.dsp_hipct.value |= regs.ADSP_IPC_HIPCT_BUSY
+
+    # Use Device library for controlling registers
+    device = Device()
+    device.open_device()
+
+    mailbox_poll_mem(device)