runners: nrf: Default to ERASE_NONE for the nRF54L series

The Nordic nRF54L series ICs use RRAM instead of flash. This implies
that erasing the internal storage before writing the new firmware is not
required anymore (unlike NOR flash, which does).
Note that RRAM on nRF54L devices is not physically paged, and paging is
only artificially provided, with a page size of 4096 bytes, for an easier
transition of nRF52 software to nRF54L devices.
In order to speed up the flashing operation and avoiding doing wasteful
write operations on the RRAM, default to ERASE_NONE for ICs in these
series.
A new ``--erase-pages`` command-line switch has been added to allow
users to keep erasing the pages that will be written to the firmware.

Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>

Author: carlescufi

doc/releases/migration-guide-4.2.rst

@@ -38,6 +38,15 @@ Boards
   nRF Util can be found
   `here <https://docs.nordicsemi.com/bundle/nrfutil/page/README.html>`_.
 
+* All boards based on a Nordic IC of the nRF54L series now default to not
+  erasing any part of the internal storage when flashing. If you'd like to
+  revert to the previous default of erasing the pages that will be written to by
+  the firmware to be flashed you can use the new ``--erase-pages`` command-line
+  switch when invoking ``west flash``.
+  Note that RRAM on nRF54L devices is not physically paged, and paging is
+  only artificially provided, with a page size of 4096 bytes, for an easier
+  transition of nRF52 software to nRF54L devices.
+
 * The config option :kconfig:option:`CONFIG_NATIVE_POSIX_SLOWDOWN_TO_REAL_TIME` has been deprecated
   in favor of :kconfig:option:`CONFIG_NATIVE_SIM_SLOWDOWN_TO_REAL_TIME`.
 

scripts/west_commands/runners/nrf_common.py

@@ -79,7 +79,8 @@ class NrfBinaryRunner(ZephyrBinaryRunner):
     '''Runner front-end base class for nrf tools.'''
 
     def __init__(self, cfg, family, softreset, pinreset, dev_id, erase=False,
-                 reset=True, tool_opt=None, force=False, recover=False):
+                 erase_pages=False, reset=True, tool_opt=None, force=False,
+                 recover=False):
         super().__init__(cfg)
         self.hex_ = cfg.hex_file
         # The old --nrf-family options takes upper-case family names
@@ -88,6 +89,7 @@ def __init__(self, cfg, family, softreset, pinreset, dev_id, erase=False,
         self.pinreset = pinreset
         self.dev_id = dev_id
         self.erase = bool(erase)
+        self.erase_pages = bool(erase_pages)
         self.reset = bool(reset)
         self.force = force
         self.recover = bool(recover)
@@ -137,6 +139,9 @@ def do_add_parser(cls, parser):
                             help='''erase all user available non-volatile
                             memory and disable read back protection before
                             flashing (erases flash for both cores on nRF53)''')
+        parser.add_argument('--erase-pages', required=False,
+                            action='store_true', dest='erase_pages',
+                            help='erase pages to be used by the firmware')
 
         parser.set_defaults(reset=True)
 
@@ -413,9 +418,13 @@ def program_hex(self):
         else:
             if self.erase:
                 erase_arg = 'ERASE_ALL'
+            elif self.family == 'nrf54l' and not self.erase_pages:
+                erase_arg = 'ERASE_NONE'
             else:
                 erase_arg = 'ERASE_RANGES_TOUCHED_BY_FIRMWARE'
 
+        self.logger.debug(f'Erase type: {erase_arg}')
+
         xip_ranges = {
             'nrf52': (0x12000000, 0x19FFFFFF),
             'nrf53': (0x10000000, 0x1FFFFFFF),
@@ -424,7 +433,9 @@ def program_hex(self):
         if self.family in xip_ranges:
             xip_start, xip_end = xip_ranges[self.family]
             if self.hex_refers_region(xip_start, xip_end):
-                ext_mem_erase_opt = erase_arg
+                # Default to pages for the external memory
+                ext_mem_erase_opt = erase_arg if erase_arg == 'ERASE_ALL' else \
+                                    'ERASE_RANGES_TOUCHED_BY_FIRMWARE'
 
         self.op_program(self.hex_, erase_arg, ext_mem_erase_opt, defer=True, core=core)
         self.flush(force=False)
@@ -517,6 +528,16 @@ def do_run(self, command, **kwargs):
             raise RuntimeError('Options --softreset and --pinreset are mutually '
                                'exclusive.')
 
+        if self.erase and self.erase_pages:
+            raise RuntimeError('Options --erase and --erase-pages are mutually '
+                               'exclusive.')
+
+        self.ensure_family()
+
+        if self.family != 'nrf54l' and self.erase_pages:
+            raise RuntimeError('Option --erase-pages can only be used with the '
+                               'nRF54L family.')
+
         self.ensure_output('hex')
         if IntelHex is None:
             raise RuntimeError('Python dependency intelhex was missing; '
@@ -527,7 +548,6 @@ def do_run(self, command, **kwargs):
             self.hex_contents.loadfile(self.hex_, format='hex')
 
         self.ensure_snr()
-        self.ensure_family()
 
         self.ops = deque()
 

scripts/west_commands/runners/nrfjprog.py

@@ -18,11 +18,11 @@ class NrfJprogBinaryRunner(NrfBinaryRunner):
     '''Runner front-end for nrfjprog.'''
 
     def __init__(self, cfg, family, softreset, pinreset, dev_id, erase=False,
-                 reset=True, tool_opt=None, force=False, recover=False,
-                 qspi_ini=None):
+                 erase_pages=False, reset=True, tool_opt=None, force=False,
+                 recover=False, qspi_ini=None):
 
-        super().__init__(cfg, family, softreset, pinreset, dev_id, erase, reset,
-                         tool_opt, force, recover)
+        super().__init__(cfg, family, softreset, pinreset, dev_id, erase,
+                         erase_pages, reset, tool_opt, force, recover)
 
         self.qspi_ini = qspi_ini
 
@@ -46,7 +46,7 @@ def tool_opt_help(cls) -> str:
     def do_create(cls, cfg, args):
         return NrfJprogBinaryRunner(cfg, args.nrf_family, args.softreset,
                                     args.pinreset, args.dev_id, erase=args.erase,
-                                    reset=args.reset,
+                                    erase_pages=args.erase_pages, reset=args.reset,
                                     tool_opt=args.tool_opt, force=args.force,
                                     recover=args.recover, qspi_ini=args.qspi_ini)
     @classmethod

scripts/west_commands/runners/nrfutil.py

@@ -17,11 +17,11 @@ class NrfUtilBinaryRunner(NrfBinaryRunner):
     '''Runner front-end for nrfutil.'''
 
     def __init__(self, cfg, family, softreset, pinreset, dev_id, erase=False,
-                 reset=True, tool_opt=None, force=False, recover=False,
-                 suit_starter=False, ext_mem_config_file=None):
+                 erase_pages=False, reset=True, tool_opt=None, force=False,
+                 recover=False, suit_starter=False, ext_mem_config_file=None):
 
-        super().__init__(cfg, family, softreset, pinreset, dev_id, erase, reset,
-                         tool_opt, force, recover)
+        super().__init__(cfg, family, softreset, pinreset, dev_id, erase,
+                         erase_pages, reset, tool_opt, force, recover)
 
         self.suit_starter = suit_starter
         self.ext_mem_config_file = ext_mem_config_file
@@ -50,7 +50,7 @@ def tool_opt_help(cls) -> str:
     def do_create(cls, cfg, args):
         return NrfUtilBinaryRunner(cfg, args.nrf_family, args.softreset,
                                    args.pinreset, args.dev_id, erase=args.erase,
-                                   reset=args.reset,
+                                   erase_pages=args.erase_pages, reset=args.reset,
                                    tool_opt=args.tool_opt, force=args.force,
                                    recover=args.recover,
                                    suit_starter=args.suit_manifest_starter,
@@ -66,7 +66,6 @@ def do_add_parser(cls, parser):
                             dest='ext_mem_config_file',
                             help='path to an JSON file with external memory configuration')
 
-
     def _exec(self, args):
         jout_all = []