Revert "device: simplify structure of handles array"

This reverts commit ec331c6.

Although it's a valid simplification under the assumption that we're
going to be padding the array out anyway, it would use extra ROM if we
fix the build system issues that are currently forcing gen_handles.py
to introduce extra padding in the handles arrays for linker pass 2.

On the (perhaps optimistic) assumption that we're going to fix the
build system, let's get rid of a commit that would get in the way. The
extra "complexity" in device_required_handles_get() is trivial.

This gets rid of a comment describing the linker passes, but the
structure of the comment is a bit misleading (and it contains
incorrect information for the results of pass 2: the terminator at the
end is DEVICE_HANDLE_ENDS, not DEVICE_HANDLE_NULL).

Signed-off-by: Martí Bolívar <[email protected]>

Author: mbolivar-nordic

include/device.h

@@ -479,7 +479,8 @@ device_required_handles_get(const struct device *dev,
 	if (rv != NULL) {
 		size_t i = 0;
 
-		while (rv[i] != DEVICE_HANDLE_SEP) {
+		while ((rv[i] != DEVICE_HANDLE_ENDS)
+		       && (rv[i] != DEVICE_HANDLE_SEP)) {
 			++i;
 		}
 		*count = i;
@@ -693,22 +694,6 @@ static inline bool device_is_ready(const struct device *dev)
  * in a distinct pass1 section (which will be replaced by
  * postprocessing).
  *
- * Before processing in gen_handles.py, the array format is:
- * {
- *     DEVICE_ORDINAL (or DEVICE_HANDLE_NULL if not a devicetree node),
- *     List of devicetree dependency ordinals (if any),
- *     DEVICE_HANDLE_SEP,
- *     List of injected dependency ordinals (if any),
- * }
- *
- * After processing in gen_handles.py, the format is updated to:
- * {
- *     List of existing devicetree dependency handles (if any),
- *     DEVICE_HANDLE_SEP,
- *     List of injected dependency ordinals (if any),
- *     DEVICE_HANDLE_NULL padding to original length (at least one)
- * }
- *
  * It is also (experimentally) necessary to provide explicit alignment
  * on each object. Otherwise x86-64 builds will introduce padding
  * between objects in the same input section in individual object

scripts/gen_handles.py

@@ -300,11 +300,10 @@ def main():
                         dep_paths.append(dn.path)
                     else:
                         dep_paths.append('(%s)' % dn.path)
-            # Force separator to signal start of injected dependencies
-            hdls.append(DEVICE_HANDLE_SEP)
             if len(hs.ext_deps) > 0:
                 # TODO: map these to something smaller?
                 ext_paths.extend(map(str, hs.ext_deps))
+                hdls.append(DEVICE_HANDLE_SEP)
                 hdls.extend(hs.ext_deps)
 
             # When CONFIG_USERSPACE is enabled the pre-built elf is