gdb: connect will now fail if flash autoprobe fails

This stops GDB from launching with an empty memory map,
making gdb load w/flashing fail for no obvious reason.

The error message points in the direction of the gdb-attach
event that can be set up to issue a halt or "reset init"
which will put GDB in a well defined stated upon attach
and thus have a robust flash autoprobe.

Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

src/flash/nor/core.c

@@ -220,22 +220,25 @@ struct flash_bank *get_flash_bank_by_name(const char *name)
 	return NULL;
 }
 
-struct flash_bank *get_flash_bank_by_num(int num)
+int get_flash_bank_by_num(int num, struct flash_bank **bank)
 {
 	struct flash_bank *p = get_flash_bank_by_num_noprobe(num);
 	int retval;
 
 	if (p == NULL)
-		return NULL;
+	{
+		return ERROR_FAIL;
+	}
 
 	retval = p->driver->auto_probe(p);
 
 	if (retval != ERROR_OK)
 	{
 		LOG_ERROR("auto_probe failed %d\n", retval);
-		return NULL;
+		return retval;
 	}
-	return p;
+	*bank = p;
+	return ERROR_OK;
 }
 
 /* lookup flash bank by address */

src/flash/nor/core.h

@@ -157,9 +157,10 @@ struct flash_bank *get_flash_bank_by_name(const char *name);
 /**
  * Returns a flash bank by the specified flash_bank_s bank_number, @a num.
  * @param num The flash bank number.
- * @returns A struct flash_bank for flash bank @a num, or NULL
+ * @param bank returned bank if fn returns ERROR_OK
+ * @returns ERROR_OK if successful
  */
-struct flash_bank *get_flash_bank_by_num(int num);
+int get_flash_bank_by_num(int num, struct flash_bank **bank);
 /**
  * Retreives @a bank from a command argument, reporting errors parsing
  * the bank identifier or retreiving the specified bank.  The bank

src/flash/nor/tcl.c

@@ -42,13 +42,7 @@ COMMAND_HELPER(flash_command_get_bank, unsigned name_index,
 	unsigned bank_num;
 	COMMAND_PARSE_NUMBER(uint, name, bank_num);
 
-	*bank = get_flash_bank_by_num(bank_num);
-	if (!*bank)
-	{
-		command_print(CMD_CTX, "flash bank '%s' not found", name);
-		return ERROR_INVALID_ARGUMENTS;
-	}
-	return ERROR_OK;
+	return get_flash_bank_by_num(bank_num, bank);
 }
 
 
@@ -310,9 +304,12 @@ COMMAND_HANDLER(handle_flash_erase_command)
 	uint32_t last;
 
 	COMMAND_PARSE_NUMBER(u32, CMD_ARGV[0], bank_nr);
-	struct flash_bank *p = get_flash_bank_by_num(bank_nr);
-	if (!p)
-		return ERROR_OK;
+
+	struct flash_bank *p;
+	int retval;
+	retval = get_flash_bank_by_num(bank_nr, &p);
+	if (retval != ERROR_OK)
+		return retval;
 
 	COMMAND_PARSE_NUMBER(u32, CMD_ARGV[1], first);
 	if (strcmp(CMD_ARGV[2], "last") == 0)
@@ -320,7 +317,6 @@ COMMAND_HANDLER(handle_flash_erase_command)
 	else
 		COMMAND_PARSE_NUMBER(u32, CMD_ARGV[2], last);
 
-	int retval;
 	if ((retval = flash_check_sector_parameters(CMD_CTX,
 			first, last, p->num_sectors)) != ERROR_OK)
 		return retval;
@@ -350,9 +346,10 @@ COMMAND_HANDLER(handle_flash_protect_command)
 	uint32_t last;
 
 	COMMAND_PARSE_NUMBER(u32, CMD_ARGV[0], bank_nr);
-	struct flash_bank *p = get_flash_bank_by_num(bank_nr);
-	if (!p)
-		return ERROR_OK;
+	struct flash_bank *p;
+	int retval = get_flash_bank_by_num(bank_nr, &p);
+	if (retval != ERROR_OK)
+		return retval;
 
 	COMMAND_PARSE_NUMBER(u32, CMD_ARGV[1], first);
 	if (strcmp(CMD_ARGV[2], "last") == 0)
@@ -363,7 +360,6 @@ COMMAND_HANDLER(handle_flash_protect_command)
 	bool set;
 	COMMAND_PARSE_ON_OFF(CMD_ARGV[3], set);
 
-	int retval;
 	if ((retval = flash_check_sector_parameters(CMD_CTX,
 			first, last, p->num_sectors)) != ERROR_OK)
 		return retval;

src/server/gdb_server.c

@@ -855,6 +855,26 @@ static int gdb_new_connection(struct connection *connection)
 		gdb_putback_char(connection, initial_ack);
 	target_call_event_callbacks(gdb_service->target, TARGET_EVENT_GDB_ATTACH);
 
+	if (gdb_use_memory_map)
+	{
+		/* Connect must fail if the memory map can't be set up correctly.
+		 *
+		 * This will cause an auto_probe to be invoked, which is either
+		 * a no-op or it will fail when the target isn't ready(e.g. not halted).
+		 */
+		int i;
+		for (i = 0; i < flash_get_bank_count(); i++)
+		{
+			struct flash_bank *p;
+			retval = get_flash_bank_by_num(i, &p);
+			if (retval != ERROR_OK)
+			{
+				LOG_ERROR("Connect failed. Consider setting up a gdb-attach event for the target to prepare target for GDB connect.");
+				return retval;
+			}
+		}
+	}
+
 	gdb_actual_connections++;
 	LOG_DEBUG("New GDB Connection: %d, Target %s, state: %s",
 		  gdb_actual_connections,
@@ -1692,10 +1712,10 @@ static int gdb_memory_map(struct connection *connection,
 	banks = malloc(sizeof(struct flash_bank *)*flash_get_bank_count());
 
 	for (i = 0; i < flash_get_bank_count(); i++) {
-		p = get_flash_bank_by_num(i);
-		if (p == NULL) {
+		retval = get_flash_bank_by_num(i, &p);
+		if (retval != ERROR_OK)
+		{
 			free(banks);
-			retval = ERROR_FAIL;
 			gdb_send_error(connection, retval);
 			return retval;
 		}