flash/nor/stm32l4x: use flash infrastructure to align write

The original code paded the write chunk with random bytes by overrunning
the buffer. An user can easily regard the random bytes to
be a programming error.

Change-Id: Ib0f47b5bc406bc6a7c32f3d929bf324a17c7c1e1
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/5359
Tested-by: jenkins
Reviewed-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>

diff --git a/src/flash/nor/stm32l4x.c b/src/flash/nor/stm32l4x.c
index 3d1537756074466676a9bd6fde6e4cd0d32ddae5..1b54193c2fe818e65514325dcc334899d59ff89b 100644 (file)
--- a/src/flash/nor/stm32l4x.c
+++ b/src/flash/nor/stm32l4x.c
@@ -278,6 +278,10 @@ FLASH_BANK_COMMAND_HANDLER(stm32l4_flash_bank_command)
                return ERROR_FAIL; /* Checkme: What better error to use?*/
        bank->driver_priv = stm32l4_info;
 
+       /* The flash write must be aligned to a double word (8-bytes) boundary.
+        * Ask the flash infrastructure to ensure required alignment */
+       bank->write_start_alignment = bank->write_end_alignment = 8;
+
        stm32l4_info->probed = 0;
 
        return ERROR_OK;
@@ -679,30 +683,15 @@ static int stm32l4_write(struct flash_bank *bank, const uint8_t *buffer,
                return ERROR_TARGET_NOT_HALTED;
        }
 
-       if (offset & 0x7) {
-               LOG_WARNING("offset 0x%" PRIx32 " breaks required 8-byte alignment",
-                                       offset);
-               return ERROR_FLASH_DST_BREAKS_ALIGNMENT;
-       }
-
-       if (count & 0x7) {
-               LOG_WARNING("Padding %d bytes to keep 8-byte write size",
-                                       count & 7);
-               count = (count + 7) & ~7;
-               /* This pads the write chunk with random bytes by overrunning the
-                * write buffer. Padding with the erased pattern 0xff is purely
-                * cosmetical, as 8-byte flash words are ECC secured and the first
-                * write will program the ECC bits. A second write would need
-                * to reprogramm these ECC bits.
-                * But this can only be done after erase!
-                */
-       }
+       /* The flash write must be aligned to a double word (8-bytes) boundary.
+        * The flash infrastructure ensures it, do just a security check */
+       assert(offset % 8 == 0);
+       assert(count % 8 == 0);
 
        retval = stm32l4_unlock_reg(bank);
        if (retval != ERROR_OK)
                return retval;
 
-       /* Only full double words (8-byte) can be programmed*/
        retval = stm32l4_write_block(bank, buffer, offset, count / 2);
        if (retval != ERROR_OK) {
                LOG_WARNING("block write failed");