at91samd: Bail early if trying to erase protected sector

Bail early if trying to erase protected sector and also do not double-erase already
erased sectors.

Change-Id: Ic2d39af48c3b8e10e78d52dd978b9bc01f671c6a
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-on: http://openocd.zylin.com/2026


Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

src/flash/nor/at91samd.c

@@ -360,6 +360,12 @@ static int samd_erase(struct flash_bank *bank, int first, int last)
 
 	/* For each sector to be erased */
 	for (int s = first; s <= last; s++) {
+		if (bank->sectors[s].is_protected) {
+			LOG_ERROR("SAMD: failed to erase sector %d. That sector is write-protected", s);
+			return ERROR_FLASH_OPERATION_FAILED;
+		}
+
+		if (!bank->sectors[s].is_erased) {
 			/* For each row in that sector */
 			for (int r = s * rows_in_sector; r < (s + 1) * rows_in_sector; r++) {
 				res = samd_erase_row(bank, r * chip->page_size * 4);
@@ -371,6 +377,7 @@ static int samd_erase(struct flash_bank *bank, int first, int last)
 
 			bank->sectors[s].is_erased = 1;
 		}
+	}
 
 	return ERROR_OK;
 }