flash: add padded_value cmd

This adds support for setting the default value used when padding image
sections. Previously 0xff was used but some targets have an erased value
of 0x00.

Change-Id: If3df6fea3abf95b09daa3ff7be362acf991070ce
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/1635
Tested-by: jenkins

doc/openocd.texi

@@ -4862,6 +4862,12 @@ specifies "to the end of the flash bank".
 The @var{num} parameter is a value shown by @command{flash banks}.
 @end deffn
 
+@deffn Command {flash padded_value} num value
+Sets the default value used for padding any image sections, This should
+normally match the flash bank erased value. If not specified by this
+comamnd or the flash driver then it defaults to 0xff.
+@end deffn
+
 @anchor{program}
 @deffn Command {program} filename [verify] [reset] [offset]
 This is a helper script that simplifies using OpenOCD as a standalone

src/flash/nor/core.c

@@ -710,7 +710,7 @@ int flash_write_unlock(struct target *target, struct image *image,
 
 			/* see if we need to pad the section */
 			while (padding[section]--)
-				(buffer + buffer_size)[size_read++] = 0xff;
+				(buffer + buffer_size)[size_read++] = c->default_padded_value;
 
 			buffer_size += size_read;
 			section_offset += size_read;

src/flash/nor/core.h

@@ -87,6 +87,10 @@ struct flash_bank {
 	int chip_width; /**< Width of the chip in bytes (1,2,4 bytes) */
 	int bus_width; /**< Maximum bus width, in bytes (1,2,4 bytes) */
 
+	/** Default padded value used, normally this matches the  flash
+	 * erased value. Defaults to 0xFF. */
+	uint8_t default_padded_value;
+
 	/**
 	 * The number of sectors on this chip.  This value will
 	 * be set intially to 0, and the flash driver must set this to

src/flash/nor/tcl.c

@@ -605,6 +605,24 @@ void flash_set_dirty(void)
 	}
 }
 
+COMMAND_HANDLER(handle_flash_padded_value_command)
+{
+	if (CMD_ARGC != 2)
+		return ERROR_COMMAND_SYNTAX_ERROR;
+
+	struct flash_bank *p;
+	int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &p);
+	if (ERROR_OK != retval)
+		return retval;
+
+	COMMAND_PARSE_NUMBER(u8, CMD_ARGV[1], p->default_padded_value);
+
+	command_print(CMD_CTX, "Default padded value set to 0x%" PRIx8 " for flash bank %u", \
+			p->default_padded_value, p->bank_number);
+
+	return retval;
+}
+
 static const struct command_registration flash_exec_command_handlers[] = {
 	{
 		.name = "probe",
@@ -700,6 +718,13 @@ static const struct command_registration flash_exec_command_handlers[] = {
 		.help = "Turn protection on or off for a range of sectors "
 			"in a given flash bank.",
 	},
+	{
+		.name = "padded_value",
+		.handler = handle_flash_padded_value_command,
+		.mode = COMMAND_EXEC,
+		.usage = "bank_id value",
+		.help = "Set default flash padded value",
+	},
 	COMMAND_REGISTRATION_DONE
 };
 
@@ -712,7 +737,6 @@ static int flash_init_drivers(struct command_context *cmd_ctx)
 	return register_commands(cmd_ctx, parent, flash_exec_command_handlers);
 }
 
-
 COMMAND_HANDLER(handle_flash_bank_command)
 {
 	if (CMD_ARGC < 7) {
@@ -765,6 +789,7 @@ COMMAND_HANDLER(handle_flash_bank_command)
 	COMMAND_PARSE_NUMBER(u32, CMD_ARGV[2], c->size);
 	COMMAND_PARSE_NUMBER(int, CMD_ARGV[3], c->chip_width);
 	COMMAND_PARSE_NUMBER(int, CMD_ARGV[4], c->bus_width);
+	c->default_padded_value = 0xff;
 	c->num_sectors = 0;
 	c->sectors = NULL;
 	c->next = NULL;

src/flash/nor/virtual.c

@@ -46,6 +46,7 @@ static void virtual_update_bank_info(struct flash_bank *bank)
 	bank->size = master_bank->size;
 	bank->chip_width = master_bank->chip_width;
 	bank->bus_width = master_bank->bus_width;
+	bank->default_padded_value = master_bank->default_padded_value;
 	bank->num_sectors = master_bank->num_sectors;
 	bank->sectors = master_bank->sectors;
 }