apps/system/ymodem: Optimized ymodem for burn during bootloader

If device automatically enters the ymodem rb mode when it starts up,
the PC tool does not need to send rb command anymore. Here, when a
specified number of consecutive 'C' are received, the subsequent
ymodem protocol content will continue.

Signed-off-by: wangxingxing <wangxingxing@xiaomi.com>

system/ymodem/sbrb.py

@@ -25,6 +25,7 @@ import io
 import os
 import sys
 import termios
+import time
 
 import serial
 
@@ -92,25 +93,31 @@ def ymodem_stdprogress(data):
 
 
 def ymodem_ser_read(size):
-    global fd_serial
-
     data = fd_serial.read(size)
     return data
 
 
 def ymodem_ser_write(data):
-    global fd_serial
     fd_serial.write(data)
     fd_serial.flush()
 
 
 def ymodem_ser_clear():
-    global fd_serial
-
     fd_serial.reset_input_buffer()
     fd_serial.reset_output_buffer()
 
 
+def ymodem_ser_recv_repeat_c(num, timeout):
+    except_data = b"C" * num
+    start_time = time.time()
+
+    while time.time() - start_time < timeout:
+        read_data = ymodem_ser_read(num)
+        if read_data == except_data:
+            return 0
+    return -1
+
+
 def calc_crc16(data, crc=0):
     crctable = [
         0x0000,
@@ -385,7 +392,7 @@ class ymodem:
         write=ymodem_stdwrite,
         progress=ymodem_stdprogress,
         clear=ymodem_stdclear,
-        timeout=100,
+        timeout=10,
         maxretry=RETRIESMAX,
         debug="",
         customsize=0,
@@ -452,15 +459,30 @@ class ymodem:
         return PACKET_SIZE
 
     def recv_cmd(self, cmd):
-        chunk = self.read(1)
-        if chunk == NAK:
-            return -EAGAIN
-        if chunk != cmd:
-            self.debug("should be " + binascii.hexlify(cmd).decode("utf-8"))
-            self.debug("but receive " + binascii.hexlify(chunk).decode("utf-8") + "\n")
-            return -EINVAL
-
-        return 0
+        start_time = time.time()
+        unexpected_buffer = b""
+        while time.time() - start_time < self.timeout:
+            chunk = self.read(1)
+            if chunk == cmd:
+                if unexpected_buffer:
+                    # try to decode to UTF-8
+                    decoded = unexpected_buffer.decode("utf-8", errors="replace")
+                    self.progress(f"Ignored unexpected text: {decoded}\n")
+                return 0
+            elif chunk == NAK:
+                if unexpected_buffer:
+                    decoded = unexpected_buffer.decode("utf-8", errors="replace")
+                    self.progress(f"Ignored unexpected text: {decoded}\n")
+                print("EAGAIN!!!")
+                return -EAGAIN
+            elif chunk == b"":
+                continue
+            else:
+                unexpected_buffer += chunk
+        if unexpected_buffer:
+            decoded = unexpected_buffer.decode("utf-8", errors="replace")
+            self.progress(f"Ignored unexpected text: {decoded}\n")
+        return -EINVAL
 
     def send_handshake(self):
         self.write(CRC)
@@ -686,7 +708,7 @@ class ymodem:
                     return -1
 
                 self.progress("recv ret %d\n" % ret)
-                self.debug("recv frist packet\n")
+                self.debug("recv first packet\n")
                 self.retries += 1
                 continue
 
@@ -807,6 +829,29 @@ if __name__ == "__main__":
         help="This opthin set max retry for transmission",
     )
 
+    parser.add_argument(
+        "-c",
+        "--countofc",
+        type=int,
+        default=0,
+        help="""
+            When this value is greater than 0, it means that the rb command is not sent to
+            device, but to receive a specified number of consecutive 'C'.
+            If do not receive continuous 'C', time out and exit.
+            """,
+    )
+
+    parser.add_argument(
+        "-w",
+        "--waitctimeout",
+        type=int,
+        default=30,
+        help="""
+            When the -c parameter is valid, this arg will determine whether it has timed out
+            while waiting for consecutive Cs. The unit is second.
+            """,
+    )
+
     parser.add_argument(
         "--debug", help="This opthin is save debug log on host", default=""
     )
@@ -821,19 +866,34 @@ if __name__ == "__main__":
             for i in args.recvfrom:
                 recvfile += i + " "
 
+            if args.kblocksize:
+                recvfile += "-k %d " % (args.kblocksize)
+
             fd_serial.write(("sb %s\r\n" % (recvfile)).encode())
             fd_serial.flush()
             tmp = fd_serial.read(len(("sb %s\r\n" % (recvfile)).encode()) - 1)
             fd_serial.reset_input_buffer()
         else:
-            if args.sendto:
-                cmd = ("rb -f %s\r\n" % (args.sendto[0])).encode()
+            if args.countofc:
+                ret = ymodem_ser_recv_repeat_c(args.countofc, args.waitctimeout)
+                if ret < 0:
+                    print("read C timeout")
+                    fd_serial.close()
+                    sys.exit(1)
             else:
-                cmd = ("rb\r\n").encode()
+                if args.sendto:
+                    cmd = ("rb -f %s" % args.sendto[0]).encode()
+                else:
+                    cmd = "rb".encode()
 
-            fd_serial.write(cmd)
-            fd_serial.flush()
-            fd_serial.read(len(cmd))
+                if args.kblocksize:
+                    cmd += (" -k %d" % args.kblocksize).encode()
+
+                cmd += b"\r\n"
+
+                fd_serial.write(cmd)
+                fd_serial.flush()
+                fd_serial.read(len(cmd))
 
             fd_serial.reset_input_buffer()
         sbrb = ymodem(