svn commit: r271190 - head/sys/dev/ofw

[Ian Lepore]

On Sat, 2014-09-06 at 08:39 -0700, Nathan Whitehorn wrote:
> On 09/06/14 08:34, Ian Lepore wrote:
> > On Sat, 2014-09-06 at 08:25 -0700, Nathan Whitehorn wrote:
> >> What is this for? The way the specification works here explicitly
> >> requires this fallback.
> >> -Nathan
> >>
> > It's for determining whether there is an entry in the device<->xref
> > list.  If a node has no xref phandle property there will be no entry for
> > it in the list and thus no way to record or retrieve a device
> > association.  I found myself coding the "if it has a phandle, or an
> > ibm,phandle, or a linux,phandle" incantation, then realized that all
> > that figuring-out work was done at init time when the xref list is
> > built, I just needed a way to get the result.
> 
> This isn't true. On most but not all real OF systems, which use, or will 
> use, the same mechanism, there is no distinction between "regular" and 
> "cross-reference" phandles and device tree cross-references still exist 
> with no explicit phandle property. So registering a device without a 
> phandle property has to to work, and has to fall back to the regular 
> phandle 100% of the time.
> 

Oh.  That wasn't clear when you helped me last week with the xref list
stuff.  I'll have to rework that a bit to meet the requirements you list
above.

-- Ian

> What may be true is that no single device tree has a mixture of implicit 
> and explicit cross-reference handles, so you could set a flag or 
> something. But it's probably not worth it. Do you have a concrete 
> example where you cared about this?
> -Nathan
> 
> > -- Ian
> >
> >> On 09/06/14 08:11, Ian Lepore wrote:
> >>> Author: ian
> >>> Date: Sat Sep  6 15:11:35 2014
> >>> New Revision: 271190
> >>> URL: http://svnweb.freebsd.org/changeset/base/271190
> >>>
> >>> Log:
> >>>     Add OF_xref_from_node_strict() which returns -1 if there is no xref handle
> >>>     for the node.  The default routine returns the untranslated handle, which
> >>>     is sometimes useful, but sometimes you really need to know there's no
> >>>     entry in the xref<->node<->device translation table.
> >>>
> >>> Modified:
> >>>     head/sys/dev/ofw/openfirm.c
> >>>     head/sys/dev/ofw/openfirm.h
> >>>
> >>> Modified: head/sys/dev/ofw/openfirm.c
> >>> ==============================================================================
> >>> --- head/sys/dev/ofw/openfirm.c	Sat Sep  6 13:21:07 2014	(r271189)
> >>> +++ head/sys/dev/ofw/openfirm.c	Sat Sep  6 15:11:35 2014	(r271190)
> >>> @@ -554,15 +554,15 @@ OF_node_from_xref(phandle_t xref)
> >>>    	return (node);
> >>>    }
> >>>    
> >>> -phandle_t
> >>> -OF_xref_from_node(phandle_t node)
> >>> +static phandle_t
> >>> +xref_from_node(phandle_t node, phandle_t notfoundvalue)
> >>>    {
> >>>    	struct xrefinfo *xi;
> >>>    	phandle_t xref;
> >>>    
> >>>    	if (xref_init_done) {
> >>>    		if ((xi = xrefinfo_find(node, FIND_BY_NODE)) == NULL)
> >>> -			return (node);
> >>> +			return (notfoundvalue);
> >>>    		return (xi->xref);
> >>>    	}
> >>>    
> >>> @@ -570,10 +570,24 @@ OF_xref_from_node(phandle_t node)
> >>>    	    -1 && OF_getencprop(node, "ibm,phandle", &xref,
> >>>    	    sizeof(xref)) == -1 && OF_getencprop(node,
> >>>    	    "linux,phandle", &xref, sizeof(xref)) == -1)
> >>> -		return (node);
> >>> +		return (notfoundvalue);
> >>>    	return (xref);
> >>>    }
> >>>    
> >>> +phandle_t
> >>> +OF_xref_from_node(phandle_t node)
> >>> +{
> >>> +
> >>> +	return (xref_from_node(node, node));
> >>> +}
> >>> +
> >>> +phandle_t
> >>> +OF_xref_from_node_strict(phandle_t node)
> >>> +{
> >>> +
> >>> +	return (xref_from_node(node, -1));
> >>> +}
> >>> +
> >>>    device_t
> >>>    OF_device_from_xref(phandle_t xref)
> >>>    {
> >>>
> >>> Modified: head/sys/dev/ofw/openfirm.h
> >>> ==============================================================================
> >>> --- head/sys/dev/ofw/openfirm.h	Sat Sep  6 13:21:07 2014	(r271189)
> >>> +++ head/sys/dev/ofw/openfirm.h	Sat Sep  6 15:11:35 2014	(r271190)
> >>> @@ -128,10 +128,12 @@ ssize_t		OF_package_to_path(phandle_t no
> >>>     * Some OF implementations (IBM, FDT) have a concept of effective phandles
> >>>     * used for device-tree cross-references. Given one of these, returns the
> >>>     * real phandle. If one can't be found (or running on OF implementations
> >>> - * without this property), returns its input.
> >>> + * without this property), OF_xref_from_node() returns its input, while the
> >>> + * strict version returns -1.
> >>>     */
> >>>    phandle_t	OF_node_from_xref(phandle_t xref);
> >>>    phandle_t	OF_xref_from_node(phandle_t node);
> >>> +phandle_t	OF_xref_from_node_strict(phandle_t node);
> >>>    
> >>>    /*
> >>>     * When properties contain references to other nodes using xref handles it is
> >>>
> >
> 
>