debug: debug_stream: Access debug slot directly using cavstool.py

Access debug slot directly using cavstool.py, by specifying the debug
slot number where the debug_stream data is transferred.

Adds one command line parameter for selecting the debug slot directly
and adds an alternative mainloop for polling the slot through
cavstool.py direct access.

The commit also adds quite a few data consistency checks and error
handling improvements as with the direct memory access its much more
likely to get inconsistent data when the DSP is booting up, and code
needs to be robust enough not to crash in such a situation. Also the
logging messages about those checks failing has been lowered so that
they are not too noisy.

Signed-off-by: Jyri Sarha <jyri.sarha@linux.intel.com>

Author: Jyri Sarha

tools/debug_stream/debug_stream.py

@@ -18,6 +18,7 @@
 )
 
 DEBUG_STREAM_PAYLOAD_MAGIC = 0x1ED15EED
+DEBUG_SLOT_SIZE = 4096
 
 # TODO: python construct would probably be cleaner than ctypes structs
 
@@ -286,7 +287,7 @@ def catch_up(self, slot):
         self.decode_past_records(slot, circ.w_ptr, circ.next_seqno)
         self.prev_w_ptr = circ.w_ptr
         self.prev_seqno = circ.next_seqno - 1
-        logging.info("seqno %u w_ptr %u", self.prev_seqno, self.prev_w_ptr)
+        logging.debug("seqno %u w_ptr %u", self.prev_seqno, self.prev_w_ptr)
 
     def decode_past_records(self, slot, pos, seqno):
         """
@@ -373,7 +374,7 @@ class DebugStreamDecoder:
     Class for decoding debug-stream slot contents
     """
 
-    file_size = 4096  # ADSP debug slot size
+    file_size = DEBUG_SLOT_SIZE
     file = None
     slot = None
     descs = []
@@ -393,6 +394,12 @@ def update_slot(self):
         self.file.seek(0)
         self.slot = self.file.read(self.file_size)
 
+    def set_slot(self, buf):
+        """
+        Update slot contents
+        """
+        self.slot = buf
+
     def get_descriptors(self):
         """
         Read the core specific descriptors and initialize core
@@ -403,15 +410,26 @@ def get_descriptors(self):
             return False
         hdr = ctypes.cast(self.slot, ctypes.POINTER(DebugStreamSlotHdr))
         if hdr.contents.hdr.magic != DEBUG_STREAM_PAYLOAD_MAGIC:
-            logging.warning("Debug Slot has bad magic 0x%08x", hdr.contents.hdr.magic)
+            logging.info("Debug Slot has bad magic 0x%08x", hdr.contents.hdr.magic)
             return False
         num_sections = hdr.contents.num_sections
         if num_sections == len(self.descs):
             return True
+        if num_sections > 32:
+            logging.info("Suspiciously many sections %u", num_sections)
+            return False
         hsize = ctypes.sizeof(DebugStreamSlotHdr)
         self.descs = (DebugStreamSectionDescriptor * num_sections).from_buffer_copy(
             self.slot, hsize
         )
+        for i in range(len(self.descs)):
+            if (self.descs[i].core_id > 32 or
+                self.descs[i].buf_words > DEBUG_SLOT_SIZE // WSIZE or
+                self.descs[i].offset > DEBUG_SLOT_SIZE):
+             logging.info("Suspicious descriptor %u values %u %u %u", i,
+                          self.descs[i].core_id, self.descs[i].buf_words,
+                          self.descs[i].offest)
+             return False
         self.circdec = [
             CircularBufferDecoder(self.descs[i], i, self.rec_printer)
             for i in range(len(self.descs))
@@ -473,6 +491,37 @@ def reset(self):
         self.file = None
         self.slot = None
 
+def cavstool_main_loop(my_args):
+    import cavstool
+    try:
+        (hda, sd, dsp, hda_ostream_id) = cavstool.map_regs(True)
+    except Exception as e:
+        logging.error("Could not map device in sysfs; run as root?")
+        logging.error(e)
+        sys.exit(1)
+
+    decoder = DebugStreamDecoder()
+    while True:
+        if not cavstool.fw_is_alive(dsp):
+            cavstool.wait_fw_entered(dsp, timeout_s=None)
+        try:
+            offset = cavstool.debug_slot_offset(my_args.direct_access_slot);
+            buf = cavstool.win_read(offset, 0, DEBUG_SLOT_SIZE)
+            decoder.set_slot(buf)
+            if not decoder.get_descriptors():
+                time.sleep(my_args.update_interval)
+                continue
+            decoder.catch_up_all()
+            while True:
+                if decoder.poll():
+                    time.sleep(my_args.update_interval)
+                buf = cavstool.win_read(offset, 0, DEBUG_SLOT_SIZE)
+                decoder.set_slot(buf)
+                if not decoder.check_slot():
+                    break
+        except Exception as e:
+            logging.error("%s failure: %s", type(e), e.args)
+            continue
 
 def main_f(my_args):
     """
@@ -483,6 +532,8 @@ def main_f(my_args):
     about the host CPU load. That is why there where no synchronous mechanism
     done and the host simply polls for new records.
     """
+    if my_args.direct_access_slot >= 0:
+	    return cavstool_main_loop(my_args)
     decoder = DebugStreamDecoder()
     prev_error = None
     while True:
@@ -491,7 +542,8 @@ def main_f(my_args):
                 decoder.set_file(file)
                 decoder.update_slot()
                 if not decoder.get_descriptors():
-                    break
+                    time.sleep(my_args.update_interval)
+                    continue
                 decoder.catch_up_all()
                 while True:
                     if decoder.poll():
@@ -527,6 +579,13 @@ def parse_params():
         help="File to read the DebugStream data from, default /sys/kernel/debug/sof/debug_stream",
         default="/sys/kernel/debug/sof/debug_stream",
     )
+    parser.add_argument(
+        "-c",
+        "--direct-access-slot",
+        help="Access specified debug window slot directly, no need for debugfs file",
+        type=int,
+        default=-1,
+    )
     parsed_args = parser.parse_args()
     return parsed_args