From e58b7d623b4c8b4ec9317fa1bfdd27f6189f012c Mon Sep 17 00:00:00 2001
From: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Date: Mon, 6 Sep 2021 14:57:59 +0200
Subject: [PATCH] crc32: Abort generic_crc32 with error from target_mem_read

Use larger chunks for hosted to speed up. Send pure NULL as line keep-alive.
---
 src/crc32.c          | 51 +++++++++++++++++++++++++++++++++++++-------
 src/gdb_main.c       |  7 +++++-
 src/include/crc32.h  |  2 +-
 src/include/gdb_if.h |  2 ++
 4 files changed, 52 insertions(+), 10 deletions(-)

diff --git a/src/crc32.c b/src/crc32.c
index 63e3729..a56b994 100644
--- a/src/crc32.c
+++ b/src/crc32.c
@@ -20,6 +20,7 @@
 
 #include "general.h"
 #include "target.h"
+#include "gdb_if.h"
 
 #if !defined(STM32F0) && !defined(STM32F1) && !defined(STM32F2) && \
 	!defined(STM32F3) && !defined(STM32F4) && !defined(STM32F7) && \
@@ -97,14 +98,31 @@ static uint32_t crc32_calc(uint32_t crc, uint8_t data)
 	return (crc << 8) ^ crc32_table[((crc >> 24) ^ data) & 255];
 }
 
-uint32_t generic_crc32(target *t, uint32_t base, size_t len)
+int generic_crc32(target *t, uint32_t *crc_res, uint32_t base, size_t len)
 {
 	uint32_t crc = -1;
+#if PC_HOSTED == 1
+	/* Reading a 2 MByte on a H743 takes about 80 s@128, 28s @ 1k,
+	 * 22 s @ 4k and 21 s @ 64k
+	 */
+	uint8_t bytes[0x1000];
+	uint32_t start_time = platform_time_ms();
+#else
 	uint8_t bytes[128];
-
+#endif
+	uint32_t last_time = platform_time_ms();
 	while (len) {
+		uint32_t actual_time = platform_time_ms();
+		if ( actual_time > last_time + 1000) {
+			last_time = actual_time;
+			gdb_if_putchar(0, true);
+		}
 		size_t read_len = MIN(sizeof(bytes), len);
-		target_mem_read(t, bytes, base, read_len);
+		if (target_mem_read(t, bytes, base, read_len)) {
+			DEBUG_WARN("generic_crc32 error around address 0x%08" PRIx32 "\n",
+					   base);
+			return -1;
+		}
 
 		for (unsigned i = 0; i < read_len; i++)
 			crc = crc32_calc(crc, bytes[i]);
@@ -112,20 +130,32 @@ uint32_t generic_crc32(target *t, uint32_t base, size_t len)
 		base += read_len;
 		len -= read_len;
 	}
-	return crc;
+	DEBUG_WARN("%d ms\n", platform_time_ms() - start_time);
+	*crc_res = crc;
+	return 0;
 }
 #else
 #include <libopencm3/stm32/crc.h>
-uint32_t generic_crc32(target *t, uint32_t base, size_t len)
+int generic_crc32(target *t, uint32_t *crc_res, uint32_t base, size_t len)
 {
 	uint8_t bytes[128];
 	uint32_t crc;
 
 	CRC_CR |= CRC_CR_RESET;
 
+	uint32_t last_time = platform_time_ms();
 	while (len > 3) {
+		uint32_t actual_time = platform_time_ms();
+		if ( actual_time > last_time + 1000) {
+			last_time = actual_time;
+			gdb_if_putchar(0, true);
+		}
 		size_t read_len = MIN(sizeof(bytes), len) & ~3;
-		target_mem_read(t, bytes, base, read_len);
+		if (target_mem_read(t, bytes, base, read_len)) {
+			DEBUG_WARN("generic_crc32 error around address 0x%08" PRIx32 "\n",
+					   base);
+			return -1;
+		}
 
 		for (unsigned i = 0; i < read_len; i += 4)
 			CRC_DR = __builtin_bswap32(*(uint32_t*)(bytes+i));
@@ -136,7 +166,11 @@ uint32_t generic_crc32(target *t, uint32_t base, size_t len)
 
 	crc = CRC_DR;
 
-	target_mem_read(t, bytes, base, len);
+	if (target_mem_read(t, bytes, base, len)) {
+		DEBUG_WARN("generic_crc32 error around address 0x%08" PRIx32 "\n",
+				   base);
+		return -1;
+	}
 	uint8_t *data = bytes;
 	while (len--) {
 		crc ^= *data++ << 24;
@@ -147,7 +181,8 @@ uint32_t generic_crc32(target *t, uint32_t base, size_t len)
 				crc <<= 1;
 		}
 	}
-	return crc;
+	*crc_res = crc;
+	return 0;
 }
 #endif
 
diff --git a/src/gdb_main.c b/src/gdb_main.c
index 19bcc31..d453338 100644
--- a/src/gdb_main.c
+++ b/src/gdb_main.c
@@ -412,7 +412,12 @@ handle_q_packet(char *packet, int len)
 			gdb_putpacketz("E01");
 			return;
 		}
-		gdb_putpacket_f("C%lx", generic_crc32(cur_target, addr, alen));
+		uint32_t crc;
+		int res = generic_crc32(cur_target, &crc, addr, alen);
+		if (res)
+			gdb_putpacketz("E03");
+		else
+			gdb_putpacket_f("C%lx", crc);
 
 	} else {
 		DEBUG_GDB("*** Unsupported packet: %s\n", packet);
diff --git a/src/include/crc32.h b/src/include/crc32.h
index 4e0f729..7d9c65a 100644
--- a/src/include/crc32.h
+++ b/src/include/crc32.h
@@ -21,6 +21,6 @@
 #ifndef __CRC32_H
 #define __CRC32_H
 
-uint32_t generic_crc32(target *t, uint32_t base, int len);
+int generic_crc32(target *t, uint32_t *crc, uint32_t base, int len);
 
 #endif
diff --git a/src/include/gdb_if.h b/src/include/gdb_if.h
index eed1b9a..e301bdb 100644
--- a/src/include/gdb_if.h
+++ b/src/include/gdb_if.h
@@ -29,6 +29,8 @@ void gdb_usb_out_cb(usbd_device *dev, uint8_t ep);
 int gdb_if_init(void);
 unsigned char gdb_if_getchar(void);
 unsigned char gdb_if_getchar_to(int timeout);
+
+/* sending gdb_if_putchar(0, true) seems to work as keep alive */
 void gdb_if_putchar(unsigned char c, int flush);
 
 #endif