From ffebd2076c6de67000fa90168a24e1bca6ba5ff8 Mon Sep 17 00:00:00 2001
From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Mon, 26 Aug 2019 17:15:01 +0200
Subject: [PATCH] bios/tools: allow disabling CRC check on serialboot (to
 speedup debug/loading large images when only serial is available)

---
 litex/soc/software/bios/boot.c | 32 ++++++++++++++++++--------------
 litex/soc/software/bios/sfl.h  |  1 +
 litex/tools/litex_term.py      | 34 ++++++++++++++++++++--------------
 3 files changed, 39 insertions(+), 28 deletions(-)

diff --git a/litex/soc/software/bios/boot.c b/litex/soc/software/bios/boot.c
index 2801202a88..41e179f49c 100644
--- a/litex/soc/software/bios/boot.c
+++ b/litex/soc/software/bios/boot.c
@@ -122,7 +122,7 @@ int serialboot(void)
 		int actualcrc;
 		int goodcrc;
 
-		/* Grab one frame */
+		/* Get one Frame */
 		frame.length = uart_read();
 		frame.crc[0] = uart_read();
 		frame.crc[1] = uart_read();
@@ -130,26 +130,29 @@ int serialboot(void)
 		for(i=0;i<frame.length;i++)
 			frame.payload[i] = uart_read();
 
-		/* Check CRC */
-		actualcrc = ((int)frame.crc[0] << 8)|(int)frame.crc[1];
-		goodcrc = crc16(&frame.cmd, frame.length+1);
-		if(actualcrc != goodcrc) {
-			failed++;
-			if(failed == MAX_FAILED) {
-				printf("Too many consecutive errors, aborting");
-				return 1;
+		/* Check Frame CRC (if CMD has a CRC) */
+		if (frame.cmd != SFL_CMD_LOAD_NO_CRC) {
+			actualcrc = ((int)frame.crc[0] << 8)|(int)frame.crc[1];
+			goodcrc = crc16(&frame.cmd, frame.length+1);
+			if(actualcrc != goodcrc) {
+				failed++;
+				if(failed == MAX_FAILED) {
+					printf("Too many consecutive errors, aborting");
+					return 1;
+				}
+				uart_write(SFL_ACK_CRCERROR);
+				continue;
 			}
-			uart_write(SFL_ACK_CRCERROR);
-			continue;
 		}
 
-		/* CRC OK */
+		/* Execute Frame CMD */
 		switch(frame.cmd) {
 			case SFL_CMD_ABORT:
 				failed = 0;
 				uart_write(SFL_ACK_SUCCESS);
 				return 1;
-			case SFL_CMD_LOAD: {
+			case SFL_CMD_LOAD:
+			case SFL_CMD_LOAD_NO_CRC: {
 				char *writepointer;
 
 				failed = 0;
@@ -160,7 +163,8 @@ int serialboot(void)
 					|((unsigned long)frame.payload[3] <<  0));
 				for(i=4;i<frame.length;i++)
 					*(writepointer++) = frame.payload[i];
-				uart_write(SFL_ACK_SUCCESS);
+				if (frame.cmd == SFL_CMD_LOAD)
+					uart_write(SFL_ACK_SUCCESS);
 				break;
 			}
 			case SFL_CMD_JUMP: {
diff --git a/litex/soc/software/bios/sfl.h b/litex/soc/software/bios/sfl.h
index d1338732e9..32041bd5bb 100644
--- a/litex/soc/software/bios/sfl.h
+++ b/litex/soc/software/bios/sfl.h
@@ -19,6 +19,7 @@ struct sfl_frame {
 #define SFL_CMD_ABORT		0x00
 #define SFL_CMD_LOAD		0x01
 #define SFL_CMD_JUMP		0x02
+#define SFL_CMD_LOAD_NO_CRC	0x03
 
 /* Replies */
 #define SFL_ACK_SUCCESS		'K'
diff --git a/litex/tools/litex_term.py b/litex/tools/litex_term.py
index 8e68a7bbfb..e96e3e0f77 100755
--- a/litex/tools/litex_term.py
+++ b/litex/tools/litex_term.py
@@ -55,9 +55,10 @@ def getkey(self):
 sfl_payload_length = 251
 
 # General commands
-sfl_cmd_abort = b"\x00"
-sfl_cmd_load  = b"\x01"
-sfl_cmd_jump  = b"\x02"
+sfl_cmd_abort       = b"\x00"
+sfl_cmd_load        = b"\x01"
+sfl_cmd_load_no_crc = b"\x03"
+sfl_cmd_jump        = b"\x02"
 
 # Replies
 sfl_ack_success  = b"K"
@@ -126,7 +127,7 @@ def encode(self):
 
 
 class LiteXTerm:
-    def __init__(self, serial_boot, kernel_image, kernel_address, json_images):
+    def __init__(self, serial_boot, kernel_image, kernel_address, json_images, no_crc):
         self.serial_boot = serial_boot
         assert not (kernel_image is not None and json_images is not None)
         self.mem_regions = {}
@@ -138,6 +139,7 @@ def __init__(self, serial_boot, kernel_image, kernel_address, json_images):
             self.mem_regions.update(json.load(f))
             self.boot_address = self.mem_regions[list(self.mem_regions.keys())[-1]]
             f.close()
+        self.no_crc = no_crc
 
         self.reader_alive = False
         self.writer_alive = False
@@ -176,15 +178,18 @@ def send_frame(self, frame):
         retry = 1
         while retry:
             self.port.write(frame.encode())
-            # Get the reply from the device
-            reply = self.port.read()
-            if reply == sfl_ack_success:
-                retry = 0
-            elif reply == sfl_ack_crcerror:
-                retry = 1
+            if not self.no_crc:
+                # Get the reply from the device
+                reply = self.port.read()
+                if reply == sfl_ack_success:
+                    retry = 0
+                elif reply == sfl_ack_crcerror:
+                    retry = 1
+                else:
+                    print("[LXTERM] Got unknown reply '{}' from the device, aborting.".format(reply))
+                    return 0
             else:
-                print("[LXTERM] Got unknown reply '{}' from the device, aborting.".format(reply))
-                return 0
+                retry = 0
         return 1
 
     def upload(self, filename, address):
@@ -202,7 +207,7 @@ def upload(self, filename, address):
             sys.stdout.flush()
             frame = SFLFrame()
             frame_data = data[:sfl_payload_length]
-            frame.cmd = sfl_cmd_load
+            frame.cmd = sfl_cmd_load if not self.no_crc else sfl_cmd_load_no_crc
             frame.payload = current_address.to_bytes(4, "big")
             frame.payload += frame_data
             if self.send_frame(frame) == 0:
@@ -332,12 +337,13 @@ def _get_args():
     parser.add_argument("--kernel", default=None, help="kernel image")
     parser.add_argument("--kernel-adr", default="0x40000000", help="kernel address")
     parser.add_argument("--images", default=None, help="json description of the images to load to memory")
+    parser.add_argument("--no-crc", default=False, action='store_true', help="disable CRC check (speedup serialboot)")
     return parser.parse_args()
 
 
 def main():
     args = _get_args()
-    term = LiteXTerm(args.serial_boot, args.kernel, args.kernel_adr, args.images)
+    term = LiteXTerm(args.serial_boot, args.kernel, args.kernel_adr, args.images, args.no_crc)
     term.open(args.port, int(float(args.speed)))
     term.console.configure()
     term.start()