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Write granularity is chip specific

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The following write granularities exist according to my datasheet
survey: - 1 bit. Each bit can be cleared individually. - 1 byte. A byte
can be written once. Further writes to an already written byte cause
the contents to be either undefined or to stay unchanged. - 128 bytes.
If less than 128 bytes are written, the rest will be erased. Each write
to a 128-byte region will trigger an automatic erase before anything is
written. Very uncommon behaviour. - 256 bytes. If less than 256 bytes
are written, the contents of the unwritten bytes are undefined.

Note that chips with default 256-byte writes, which keep the original
contents for unwritten bytes, have a granularity of 1 byte.

Handle 1-bit, 1-byte and 256-byte write granularity.

Corresponding to flashrom svn r927.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Sean Nelson <audiohacked@gmail.com>
Acked-by: David Hendricks <dhendrix@google.com>
This commit is contained in:
Carl-Daniel Hailfinger 2010-03-08 00:42:32 +00:00
parent 7f0c3ec56b
commit e8e369fcc3
2 changed files with 67 additions and 0 deletions
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6
flash.h
View File

@ -512,6 +512,11 @@ int dediprog_spi_send_command(unsigned int writecnt, unsigned int readcnt, const
int dediprog_spi_read(struct flashchip *flash, uint8_t *buf, int start, int len);
/* flashrom.c */
enum write_granularity {
write_gran_1bit,
write_gran_1byte,
write_gran_256bytes,
};
extern enum chipbustype buses_supported;
struct decode_sizes {
uint32_t parallel;
@ -538,6 +543,7 @@ int max(int a, int b);
char *extract_param(char **haystack, char *needle, char *delim);
int check_erased_range(struct flashchip *flash, int start, int len);
int verify_range(struct flashchip *flash, uint8_t *cmpbuf, int start, int len, char *message);
int need_erase(uint8_t *have, uint8_t *want, int len, enum write_granularity gran);
char *strcat_realloc(char *dest, const char *src);
void print_version(void);
int selfcheck(void);

61
flashrom.c
View File

@ -620,6 +620,67 @@ out_free:
return ret;
}
/**
* Check if the buffer @have can be programmed to the content of @want without
* erasing. This is only possible if all chunks of size @gran are either kept
* as-is or changed from an all-ones state to any other state.
* The following write granularities (enum @gran) are known:
* - 1 bit. Each bit can be cleared individually.
* - 1 byte. A byte can be written once. Further writes to an already written
* byte cause the contents to be either undefined or to stay unchanged.
* - 128 bytes. If less than 128 bytes are written, the rest will be
* erased. Each write to a 128-byte region will trigger an automatic erase
* before anything is written. Very uncommon behaviour and unsupported by
* this function.
* - 256 bytes. If less than 256 bytes are written, the contents of the
* unwritten bytes are undefined.
*
* @have buffer with current content
* @want buffer with desired content
* @len length of the verified area
* @gran write granularity (enum, not count)
* @return 0 if no erase is needed, 1 otherwise
*/
int need_erase(uint8_t *have, uint8_t *want, int len, enum write_granularity gran)
{
int result = 0;
int i, j, limit;
switch (gran) {
case write_gran_1bit:
for (i = 0; i < len; i++)
if ((have[i] & want[i]) != want[i]) {
result = 1;
break;
}
break;
case write_gran_1byte:
for (i = 0; i < len; i++)
if ((have[i] != want[i]) && (have[i] != 0xff)) {
result = 1;
break;
}
break;
case write_gran_256bytes:
for (j = 0; j < len / 256; j++) {
limit = min (256, len - j * 256);
/* Are have and want identical? */
if (!memcmp(have + j * 256, want + j * 256, limit))
continue;
/* have needs to be in erased state. */
for (i = 0; i < limit; i++)
if (have[i] != 0xff) {
result = 1;
break;
}
if (result)
break;
}
break;
}
return result;
}
/* This function generates various test patterns useful for testing controller
* and chip communication as well as chip behaviour.
*