I'm thinking that the lpc flash drivers calc_checksum should be retired.
In it's place a warning/info should be printed with the expected
checksum so that the user can manually write a checksum
or somehow arrange the developer host PC tools to come up
with the right checksum.
The LPC flash driver has the ability to calculate a checksum
that should be stored in a specific location in the flash (0x14).
(calc_checksum option)
However, this is a very awkward feature with surprising and
confusing effects.
Consider what happens when you write an image and try
to verify:
- an image is passed to the lpc driver
- the lpc flash driver writes the image, except that it
calculates a checksum
- verification in the higher layers now fails because
the flash driver didn't write what the flash write_image
command thought it was going to write
It gets a bit worse: the flash driver modifies the memory
passed in to the flash write fn.
Typical for C function prototypes, const isn't used here
in the API to make it clear that really that argument
is a write only argument.
The attached patch modifies the lpc flash driver not to
modify the input buffer, such that "flash fillX" exhibits
the verify error.
--
Øyvind Harboe
Embedded software and hardware consulting services
http://consulting.zylin.com
### Eclipse Workspace Patch 1.0
#P openocd
Index: src/flash/lpc2000.c
===================================================================
--- src/flash/lpc2000.c (revision 1576)
+++ src/flash/lpc2000.c (working copy)
@@ -2,6 +2,9 @@
* Copyright (C) 2005 by Dominic Rath *
* dominic.r...@gmx.de *
* *
+ * Copyright (C) 2009 by Ųyvind Harboe *
+ * oyvind.har...@zylin.com *
+ * *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
@@ -17,7 +20,6 @@
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
-
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
@@ -518,21 +520,6 @@
LOG_DEBUG("first_sector: %i, last_sector: %i", first_sector,
last_sector);
- /* check if exception vectors should be flashed */
- if ((offset == 0) && (count >= 0x20) && lpc2000_info->calc_checksum)
- {
- u32 checksum = 0;
- int i = 0;
- for (i = 0; i < 8; i++)
- {
- LOG_DEBUG("0x%2.2x: 0x%8.8x", i * 4, buf_get_u32(buffer
+ (i * 4), 0, 32));
- if (i != 5)
- checksum += buf_get_u32(buffer + (i * 4), 0,
32);
- }
- checksum = 0 - checksum;
- LOG_DEBUG("checksum: 0x%8.8x", checksum);
- buf_set_u32(buffer + 0x14, 0, 32, checksum);
- }
/* allocate a working area */
if (target_alloc_working_area(target, lpc2000_info->cmd51_max_buffer,
&download_area) != ERROR_OK)
@@ -577,25 +564,31 @@
if (retval != ERROR_OK)
break;
- if (bytes_remaining >= thisrun_bytes)
+ u8 *last_buffer = malloc(thisrun_bytes);
+
+ /* check if exception vectors should be flashed */
+ if ((offset+bytes_written == 0) && (thisrun_bytes >= 0x20) &&
lpc2000_info->calc_checksum)
{
- if ((retval = target_write_buffer(bank->target,
download_area->address, thisrun_bytes, buffer + bytes_written)) != ERROR_OK)
+ u32 checksum = 0;
+ int i = 0;
+ for (i = 0; i < 8; i++)
{
- retval = ERROR_FLASH_OPERATION_FAILED;
- break;
+ LOG_DEBUG("0x%2.2x: 0x%8.8x", i * 4,
buf_get_u32(buffer + (i * 4), 0, 32));
+ if (i != 5)
+ checksum += buf_get_u32(buffer + (i *
4), 0, 32);
}
- }
- else
- {
- u8 *last_buffer = malloc(thisrun_bytes);
- u32 i;
- memcpy(last_buffer, buffer + bytes_written,
bytes_remaining);
- for (i = bytes_remaining; i < thisrun_bytes; i++)
- last_buffer[i] = 0xff;
- target_write_buffer(bank->target,
download_area->address, thisrun_bytes, last_buffer);
- free(last_buffer);
+ checksum = 0 - checksum;
+ LOG_DEBUG("checksum: 0x%8.8x", checksum);
+ buf_set_u32(last_buffer + 0x14, 0, 32, checksum);
}
+ u32 i;
+ memcpy(last_buffer, buffer + bytes_written, bytes_remaining);
+ for (i = bytes_remaining; i < thisrun_bytes; i++)
+ last_buffer[i] = 0xff;
+ target_write_buffer(bank->target, download_area->address,
thisrun_bytes, last_buffer);
+ free(last_buffer);
+
LOG_DEBUG("writing 0x%x bytes to address 0x%x", thisrun_bytes,
bank->base + offset + bytes_written);
/* Write data */
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