[flashrom] [commit] r927 - trunk
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svn at flashrom.org
Mon Mar 8 01:42:32 CET 2010
Author: hailfinger
Date: Mon Mar 8 01:42:32 2010
New Revision: 927
URL: http://flashrom.org/trac/coreboot/changeset/927
Log:
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.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
Acked-by: Sean Nelson <audiohacked at gmail.com>
Acked-by: David Hendricks <dhendrix at google.com>
Modified:
trunk/flash.h
trunk/flashrom.c
Modified: trunk/flash.h
==============================================================================
--- trunk/flash.h Sun Mar 7 23:29:28 2010 (r926)
+++ trunk/flash.h Mon Mar 8 01:42:32 2010 (r927)
@@ -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);
Modified: trunk/flashrom.c
==============================================================================
--- trunk/flashrom.c Sun Mar 7 23:29:28 2010 (r926)
+++ trunk/flashrom.c Mon Mar 8 01:42:32 2010 (r927)
@@ -620,6 +620,67 @@
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.
*
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