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author | Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> | 2010-03-08 00:42:32 +0000 |
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committer | Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> | 2010-03-08 00:42:32 +0000 |
commit | e8e369fcc38b374e8385e3415335bfcb87deb55f (patch) | |
tree | b0222eaf1d728eda3c988f504f6dd1d0fb5b3694 | |
parent | 7f0c3ec56b794313b8d23346f8b75bee711c739d (diff) | |
download | flashrom-e8e369fcc38b374e8385e3415335bfcb87deb55f.tar.gz flashrom-e8e369fcc38b374e8385e3415335bfcb87deb55f.tar.bz2 flashrom-e8e369fcc38b374e8385e3415335bfcb87deb55f.zip |
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>
-rw-r--r-- | flash.h | 6 | ||||
-rw-r--r-- | flashrom.c | 61 |
2 files changed, 67 insertions, 0 deletions
@@ -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); @@ -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. * |