Revert "sequences: improve robustness of debug sequence execution (#1774)"

This reverts commit c33f374.

Implicitly clearing sticky error bits before executing the next DAP transfer can lead to unwanted side effects.
The debug sequence is responsible for doing that if required.

Author: RobertRostohar

pyocd/debug/sequences/functions.py

@@ -46,7 +46,6 @@ class DebugSequenceCommonFunctions(DebugSequenceFunctionsDelegate):
 
     def __init__(self) -> None:
         self._ap_cache: Dict[APAddressBase, MEM_AP] = {}
-        self._transfer_error_ignored = False
 
     @property
     def target(self) -> CoreSightTarget:
@@ -144,16 +143,8 @@ def _get_dp(self, ignore_apid: bool = False) -> DebugPort:
 
     def _get_ignore_errors(self) -> bool:
         """@brief Whether the debug sequence has set __errorcontrol to ignore faults."""
-        errcontrol = self.context.get_variable('__errorcontrol') & 1
-        if errcontrol:
-            self._transfer_error_ignored = True
-        return errcontrol
-
-    def _handle_ignore_errors(self) -> None:
-        """@brief Clear sticky error bits if transfer errors were ignored."""
-        if self._transfer_error_ignored:
-            self._get_dp().clear_sticky_err()
-            self._transfer_error_ignored = False
+        errcontrol = self.context.get_variable('__errorcontrol')
+        return (errcontrol & 1) == 1
 
     def sequence(self, name: str) -> None:
         # This call will raise if the named sequence is invalid. However, we should have already
@@ -179,7 +170,6 @@ def sequence(self, name: str) -> None:
 
     def read8(self, addr: int) -> int:
         try:
-            self._handle_ignore_errors()
             return self._get_mem_ap().read8(addr)
         except exceptions.TransferError as err:
             if self._get_ignore_errors():
@@ -190,7 +180,6 @@ def read8(self, addr: int) -> int:
 
     def read16(self, addr: int) -> int:
         try:
-            self._handle_ignore_errors()
             return self._get_mem_ap().read16(addr)
         except exceptions.TransferError as err:
             if self._get_ignore_errors():
@@ -201,7 +190,6 @@ def read16(self, addr: int) -> int:
 
     def read32(self, addr: int) -> int:
         try:
-            self._handle_ignore_errors()
             return self._get_mem_ap().read32(addr)
         except exceptions.TransferError as err:
             if self._get_ignore_errors():
@@ -212,7 +200,6 @@ def read32(self, addr: int) -> int:
 
     def read64(self, addr: int) -> int:
         try:
-            self._handle_ignore_errors()
             return self._get_mem_ap().read64(addr)
         except exceptions.TransferError as err:
             if self._get_ignore_errors():
@@ -223,7 +210,6 @@ def read64(self, addr: int) -> int:
 
     def readap(self, addr: int) -> int:
         try:
-            self._handle_ignore_errors()
             ap_addr = self._get_ap_addr()
             reg_addr = ap_addr.address | addr
             return self._get_dp().read_ap(reg_addr)
@@ -236,7 +222,6 @@ def readap(self, addr: int) -> int:
 
     def readaccessap(self, addr: int) -> int:
         try:
-            self._handle_ignore_errors()
             dp = self._get_dp(True)
             apacc = dp.apacc_memory_interface
             return apacc.read32(addr)
@@ -249,7 +234,6 @@ def readaccessap(self, addr: int) -> int:
 
     def readdp(self, addr: int) -> int:
         try:
-            self._handle_ignore_errors()
             return self._get_dp(True).read_dp(addr)
         except exceptions.TransferError as err:
             if self._get_ignore_errors():
@@ -260,7 +244,6 @@ def readdp(self, addr: int) -> int:
 
     def write8(self, addr: int, val: int) -> None:
         try:
-            self._handle_ignore_errors()
             self._get_mem_ap().write8(addr, val)
             self.target.flush()
         except exceptions.TransferError as err:
@@ -271,7 +254,6 @@ def write8(self, addr: int, val: int) -> None:
 
     def write16(self, addr: int, val: int) -> None:
         try:
-            self._handle_ignore_errors()
             self._get_mem_ap().write16(addr, val)
             self.target.flush()
         except exceptions.TransferError as err:
@@ -282,7 +264,6 @@ def write16(self, addr: int, val: int) -> None:
 
     def write32(self, addr: int, val: int) -> None:
         try:
-            self._handle_ignore_errors()
             self._get_mem_ap().write32(addr, val)
             self.target.flush()
         except exceptions.TransferError as err:
@@ -293,7 +274,6 @@ def write32(self, addr: int, val: int) -> None:
 
     def write64(self, addr: int, val: int) -> None:
         try:
-            self._handle_ignore_errors()
             self._get_mem_ap().write64(addr, val)
             self.target.flush()
         except exceptions.TransferError as err:
@@ -304,7 +284,6 @@ def write64(self, addr: int, val: int) -> None:
 
     def writeap(self, addr: int, val: int) -> None:
         try:
-            self._handle_ignore_errors()
             ap_addr = self._get_ap_addr()
             reg_addr = ap_addr.address | addr
             self._get_dp().write_ap(reg_addr, val)
@@ -317,7 +296,6 @@ def writeap(self, addr: int, val: int) -> None:
 
     def writeaccessap(self, addr: int, val: int) -> None:
         try:
-            self._handle_ignore_errors()
             dp = self._get_dp(True)
             apacc = dp.apacc_memory_interface
             apacc.write32(addr, val)
@@ -330,7 +308,6 @@ def writeaccessap(self, addr: int, val: int) -> None:
 
     def writedp(self, addr: int, val: int) -> None:
         try:
-            self._handle_ignore_errors()
             self._get_dp(True).write_dp(addr, val)
             self.target.flush()
         except exceptions.TransferError as err: