Add command to erase all flash memory regions

Changes in v4:

- Replaced phex call with hex_string.

Changes in v3:

- Addressed comments by Pedro.
- Output of memory region size now in hex format.
- Misc formatting fixups.
- Addressed Simon's comments on formatting.
- Adjusted command text in the manual entry.
- Fixed up ChangeLog.
- Renamed flash_erase_all_command to flash_erase_command.

Changes in v2:

- Added NEWS entry.
- Fixed long lines.
- Address printing with paddress.

Years ago we contributed flash programming patches upstream.  The following
patch is a leftover one that complements that functionality by adding a new
command to erase all reported flash memory blocks.

The command is most useful when we're dealing with flash-enabled targets
(mostly bare-metal) and we need to reset the board for some reason.

The wiping out of flash memory regions should help the target come up with a
known clean state from which the user can load a new image and resume
debugging. It is convenient enough to do this from the debugger, and there is
also an MI command to expose this functionality to the IDE's.

gdb/doc/ChangeLog:

2017-01-20  Mike Wrighton  <mike_wrighton@codesourcery.com>
	    Luis Machado  <lgustavo@codesourcery.com>

	* gdb.texinfo (-target-flash-erase): New MI command description.
	(flash-erase): New CLI command description.

gdb/ChangeLog:

2017-01-20  Mike Wrighton  <mike_wrighton@codesourcery.com>
	    Luis Machado  <lgustavo@codesourcery.com>

	* NEWS (New commands): Mention flash-erase.
	(New MI commands): Mention target-flash-erase.
	* mi/mi-cmds.c (mi_cmd_target_flash_erase): Add target-flash-erase MI
	command.
	* mi/mi-cmds.h (mi_cmd_target_flash_erase): New declaration.
	* mi/mi-main.c (mi_cmd_target_flash_erase): New function.
	* target.c (flash_erase_command): New function.
	(initialize_targets): Add new flash-erase command.
	* target.h (flash_erase_command): New declaration.

1 files changed, 49 insertions, 0 deletions

diff --git a/gdb/target.c b/gdb/target.c
index be7367c4c9..3c409f0f61 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -3943,6 +3943,52 @@ do_monitor_command (char *cmd,
   target_rcmd (cmd, gdb_stdtarg);
 }
 
+/* Erases all the memory regions marked as flash.  CMD and FROM_TTY are
+   ignored.  */
+
+void
+flash_erase_command (char *cmd, int from_tty)
+{
+  /* Used to communicate termination of flash operations to the target.  */
+  bool found_flash_region = false;
+  struct mem_region *m;
+  struct gdbarch *gdbarch = target_gdbarch ();
+
+  VEC(mem_region_s) *mem_regions = target_memory_map ();
+
+  /* Iterate over all memory regions.  */
+  for (int i = 0; VEC_iterate (mem_region_s, mem_regions, i, m); i++)
+    {
+      /* Fetch the memory attribute.  */
+      struct mem_attrib *attrib = &m->attrib;
+
+      /* Is this a flash memory region?  */
+      if (attrib->mode == MEM_FLASH)
+        {
+          found_flash_region = true;
+          target_flash_erase (m->lo, m->hi - m->lo);
+
+	  struct cleanup *cleanup_tuple
+	      = make_cleanup_ui_out_tuple_begin_end (current_uiout,
+						     "erased-regions");
+
+          current_uiout->message (_("Erasing flash memory region at address "));
+          current_uiout->field_fmt ("address", "%s", paddress (gdbarch,
+								 m->lo));
+          current_uiout->message (", size = ");
+          current_uiout->field_fmt ("size", "%s", hex_string (m->hi - m->lo));
+          current_uiout->message ("\n");
+          do_cleanups (cleanup_tuple);
+        }
+    }
+
+  /* Did we do any flash operations?  If so, we need to finalize them.  */
+  if (found_flash_region)
+    target_flash_done ();
+  else
+    current_uiout->message (_("No flash memory regions found.\n"));
+}
+
 /* Print the name of each layers of our target stack.  */
 
 static void
@@ -4233,6 +4279,9 @@ Otherwise, any attempt to interrupt or stop will be ignored."),
 			   set_target_permissions, NULL,
 			   &setlist, &showlist);
 
+  add_com ("flash-erase", no_class, flash_erase_command,
+           _("Erase all flash memory regions."));
+
   add_setshow_boolean_cmd ("auto-connect-native-target", class_support,
 			   &auto_connect_native_target, _("\
 Set whether GDB may automatically connect to the native target."), _("\