[RFC,1/9] dt: deps: dtc: Automatically add new property 'dependencies' which contains a list of referenced phandles

Commit Message

Alexander Holler May 27, 2014, 8:31 p.m. UTC

Am 27.05.2014 22:02, schrieb Grant Likely:
> On Mon, 19 May 2014 14:35:49 +0200, Alexander Holler <[e-mail]> wrote:

>> What's still questionable about the patches for dtc is if dependencies 
>> to devices and not just drivers should be included in the new property 
>> dependencies too. My current assumption is that all devices belonging to 
>> one and the same driver don't have dependencies between each other. In 
>> other words the order in which devices will be attached to one and the 
>> same driver isn't important. If that assumption is correct it would be 
>> possible to just attach all devices belonging to a driver after the 
>> driver was loaded (also I haven't that done in my patches).
> 
> There aren't really any guarantees here. It is perfectly valid to have
> two of the same device depending on the other, or even a device with a
> different driver between the two.
> 
> There's always going to be corner cases on the dependency chain. The
> question is whether or not it is worth trying to solve every concievable
> order, or if a partway solution is good enough.

Solving dependencies always happens automatically, with or without
dependencies inbetween devices. I just ignored dependencies between pure
devices (instead changed them into dependencies between drivers) because
I'm still not sure how to handle devices at all. Below is a diff ontop
my dtc-patches to include dependencies between devices too. As said, the
changes to do so are minimal. Of course, the graphs are a bit more
complex, because they then include devices too, but that isn't any
problem for the solving algorithm at all.


 				is_parent_of(target, source))
@@ -385,9 +387,9 @@ static int __init add_deps_lnx(struct device_node
*parent,

 	if (!__of_device_is_available(node))
 		return 0;
-	if (__of_get_property(node, "compatible", NULL)) {
+//	if (__of_get_property(node, "compatible", NULL)) {
 		if (!parent->phandle) {
-			if (__of_get_property(parent, "compatible", NULL))
+//			if (__of_get_property(parent, "compatible", NULL))
 				parent->phandle = 1 + order.max_phandle++;
 		}
 		if (!node->phandle)
@@ -425,7 +427,7 @@ static int __init add_deps_lnx(struct device_node
*parent,
 		if (unlikely(rc))
 			return rc;
 		parent = node; /* change the parent only if node is a driver */
-	}
+//	}
 	for_each_child_of_node(node, child) {
 		rc = add_deps_lnx(parent, child, print_dot);
 		if (unlikely(rc))

Patch

diff --git a/scripts/dtc/dependencies.c b/scripts/dtc/dependencies.c
index 06f447b..602ec01 100644
--- a/scripts/dtc/dependencies.c
+++ b/scripts/dtc/dependencies.c
@@ -66,8 +66,10 @@  static void add_deps(struct node *dt, struct node
*node, struct property *prop)
 			continue;
 		}

-		source = find_compatible_not_disabled(node);
-		target = find_compatible_not_disabled(refnode);
+		//source = find_compatible_not_disabled(node);
+		//target = find_compatible_not_disabled(refnode);
+		source = node;
+		target = refnode;
 		if (!source || !target || source == target ||
 				is_parent_of(source, target) ||