improved reliability using sector erase,write,verify retry

Author: emard

programmer/tinyprog/__init__.py

@@ -167,7 +167,7 @@ def _read_metadata(self):
         import math
         meta_roots = (
             [self._parse_json(self.prog.read_security_register_page(p).replace(b"\x00", b"").replace(b"\xff", b"")) for p in [1, 2, 3]] +
-            [self._parse_json(self.prog.read(int(math.pow(2, p) - (4 * 1024)), (4 * 1024)).replace(b"\x00", b"").replace(b"\xff", b"")) for p in [17, 18, 19, 20, 21, 22, 23, 24]]
+            [self._parse_json(self.prog.read(int(math.pow(2, p) - (4 * 1024)), (4 * 1024) - 256).replace(b"\x00", b"").replace(b"\xff", b"")) for p in [17, 18, 19, 20, 21, 22, 23, 24]]
         )
         meta_roots = [root for root in meta_roots if root is not None]
         if len(meta_roots) > 0:
@@ -273,11 +273,14 @@ def read(self, addr, length, disable_progress=True):
         with tqdm(desc="    Reading", unit="B", unit_scale=True, total=length, disable=disable_progress) as pbar:
             while length > 0:
                 read_length = min(255, length)
-                data += self.cmd(0x0b, addr, b'\x00', read_len=read_length)
-                self.progress(read_length)
-                addr += read_length
-                length -= read_length
-                pbar.update(read_length)
+                read_payload = self.cmd(0x0b, addr, b'\x00', read_len=read_length)
+                payload_length = len(read_payload)
+                if payload_length > 0:
+                  data += read_payload
+                  self.progress(payload_length)
+                  addr += payload_length
+                  length -= payload_length
+                  pbar.update(payload_length)
             return data
 
     def write_enable(self):
@@ -301,12 +304,32 @@ def _erase(self, addr, length):
         self.wait_while_busy()
 
     def erase(self, addr, length, disable_progress=True):
+        return self.program_sectors(addr, length, disable_progress)
+
+    # for each sector: erase,program,verify
+    # this programming is much more reliable than previous program()
+    # because each written sector will be verified and in case of
+    # error, retried several times
+    # if integer value is passed to data, this will erase that much bytes
+    def program_sectors(self, addr, data, disable_progress=True, verify_only=False, retry=10):
         possible_lengths = (1, 4 * 1024, 32 * 1024, 64 * 1024)
-
-        with tqdm(desc="    Erasing", unit="B", unit_scale=True, total=length, disable=disable_progress) as pbar:
-            while length > 0:
+        retries_remaining = retry
+        data_enable = False
+        description = "    Erasing"
+        try:
+          if len(data) > 0:
+            length = len(data)
+            description = "    Writing"
+            data_enable = True
+        except:
+          length = data # probably integer = number of bytes to erase
+        offset = 0
+        write_addr = addr + offset
+        if verify_only == False:
+          with tqdm(desc=description, unit="B", unit_scale=True, total=length, disable=disable_progress) as pbar:
+            while length > 0 and retries_remaining > 0:
                 erase_length = max(p for p in possible_lengths
-                                   if p <= length and addr % p == 0)
+                                   if p <= length and write_addr % p == 0)
 
                 if erase_length == 1:
                     # there are no opcode to erase that much
@@ -320,8 +343,8 @@ def erase(self, addr, length, disable_progress=True):
                     # +------------------+------------------+----------------+
                     #  <- start_length -> <- erase_length -> <- end_length ->
 
-                    start_addr = addr & 0xfff000
-                    start_length = addr & 0xfff
+                    start_addr = write_addr & 0xfff000
+                    start_length = write_addr & 0xfff
                     erase_length = min(0x1000 - start_length, length)
                     end_addr = start_addr + start_length + erase_length
                     end_length = start_addr + 0x1000 - end_addr
@@ -344,12 +367,38 @@ def erase(self, addr, length, disable_progress=True):
                 else:
                     # there is an opcode to erase that much data
                     self.progress(erase_length)
-                    self._erase(addr, erase_length)
+                    self._erase(write_addr, erase_length)
+
+                if data_enable:
+                    # write part of the data into erased place
+                    write_data = data[offset : offset + erase_length]
+                    self.write(write_addr, write_data)
+                    read_back = self.read(write_addr, erase_length)
+                else:
+                    # forces retry compare to succeed
+                    # todo: compare erased sector against 0xFF
+                    write_data = None
+                    read_back = None
 
                 # update
-                length -= erase_length
-                addr += erase_length
-                pbar.update(erase_length)
+                if read_back == write_data:
+                    length -= erase_length
+                    write_addr += erase_length
+                    offset += erase_length
+                    retries_remaining = retry
+                    pbar.update(erase_length)
+                else:
+                    retries_remaining -= 1
+
+        if data_enable:
+            read_back = self.read(addr, len(data), disable_progress=disable_progress)
+
+            if read_back == data:
+                self.progress("Success!")
+                return True
+            else:
+                self.progress("Failure!")
+                return False
 
     # don't use this directly, use the public "write" function instead
     def _write(self, addr, data):
@@ -416,4 +465,4 @@ def program_bitstream(self, addr, bitstream):
         self.progress("Waking up SPI flash")
         self.wake()
         self.progress(str(len(bitstream)) + " bytes to program")
-        return self.program(addr, bitstream)
+        return self.program_sectors(addr, bitstream, disable_progress=False)