diff options
| -rw-r--r-- | libflash/blocklevel.c | 43 |
1 files changed, 40 insertions, 3 deletions
diff --git a/libflash/blocklevel.c b/libflash/blocklevel.c index 90bfffb..83823c5 100644 --- a/libflash/blocklevel.c +++ b/libflash/blocklevel.c @@ -17,6 +17,7 @@ #include <stdlib.h> #include <unistd.h> #include <stdio.h> +#include <stdbool.h> #include <errno.h> #include <string.h> @@ -161,6 +162,34 @@ int blocklevel_get_info(struct blocklevel_device *bl, const char **name, uint32_ return rc; } +/* + * Compare flash and memory to determine if: + * a) Erase must happen before write + * b) Flash and memory are identical + * c) Flash can simply be written to + * + * returns -1 for a + * returns 0 for b + * returns 1 for c + */ +static int blocklevel_flashcmp(const void *flash_buf, const void *mem_buf, uint32_t len) +{ + int i, same = true; + const uint8_t *f_buf, *m_buf; + + f_buf = flash_buf; + m_buf = mem_buf; + + for (i = 0; i < len; i++) { + if (m_buf[i] & ~f_buf[i]) + return -1; + if (same && (m_buf[i] != f_buf[i])) + same = false; + } + + return same ? 0 : 1; +} + int blocklevel_smart_write(struct blocklevel_device *bl, uint32_t pos, const void *buf, uint32_t len) { uint32_t erase_size; @@ -209,18 +238,26 @@ int blocklevel_smart_write(struct blocklevel_device *bl, uint32_t pos, const voi uint32_t erase_block = pos & ~(erase_size - 1); uint32_t block_offset = pos & (erase_size - 1); uint32_t size = erase_size > len ? len : erase_size; + int cmp; + + /* Write crosses an erase boundary, shrink the write to the boundary */ + if (erase_size < block_offset + size) { + size = erase_size - block_offset; + } rc = bl->read(bl, erase_block, erase_buf, erase_size); if (rc) goto out; - if (memcmp(erase_buf + block_offset, write_buf, size) != 0) { + cmp = blocklevel_flashcmp(erase_buf + block_offset, write_buf, size); + if (cmp != 0) { + if (cmp == -1) + bl->erase(bl, erase_block, erase_size); memcpy(erase_buf + block_offset, write_buf, size); - rc = bl->write(bl, erase_block, erase_buf + block_offset, size); + rc = bl->write(bl, erase_block, erase_buf, erase_size); if (rc) goto out; } - len -= size; pos += size; write_buf += size; |