Write granularity is chip specific
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>
diff --git a/flash.h b/flash.h
index 2065b3a..34b04e6 100644
--- a/flash.h
+++ b/flash.h
@@ -512,6 +512,11 @@
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 @@
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);