summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--flash.h6
-rw-r--r--flashrom.c61
2 files changed, 67 insertions, 0 deletions
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_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);
diff --git a/flashrom.c b/flashrom.c
index 03d3bd5..6a91089 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -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.
*
OpenPOWER on IntegriCloud