From 5d61b165c892853f2daf6220d2ec6577487e273a Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Wed, 25 Jul 2012 17:34:37 -0600 Subject: of: Allow busses with #size-cells=0 It's quite legitimate for a DT node to specify #size-cells=0. One example is a node that's used to collect a number of non-memory-mapped devices. In that scenario, there may be multiple child nodes with the same name (type) thus necessitating the use of unit addresses in node names, and reg properties: / { regulators { compatible = "simple-bus"; #address-cells = <1>; #size-cells = <0>; regulator@0 { compatible = "regulator-fixed"; reg = <0>; ... }; regulator@1 { compatible = "regulator-fixed"; reg = <1>; ... }; ... }; }; However, #size-cells=0 prevents translation of reg property values into the parent node's address space. In turn, this triggers the kernel to emit error messages during boot, such as: prom_parse: Bad cell count for /regulators/regulator@0 To prevent printing these error messages for legitimate DT content, a number of changes are made: 1) of_get_address()/of_get_pci_address() are modified only to validate the value of #address-cells, and not #size-cells. 2) of_can_translate_address() is added to indicate whether address translation is possible. 3) of_device_make_bus_id() is modified to name devices based on the translated address only where possible, and otherwise fall back to using the (first cell of the) raw untranslated address. 4) of_device_alloc() is modified to create memory resources for a device only if the address can be translated into the CPU's address space. Signed-off-by: Stephen Warren Signed-off-by: Rob Herring --- include/linux/of_address.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/of_address.h') diff --git a/include/linux/of_address.h b/include/linux/of_address.h index 01b925ad8d78..c3cdc1025c30 100644 --- a/include/linux/of_address.h +++ b/include/linux/of_address.h @@ -6,6 +6,7 @@ #ifdef CONFIG_OF_ADDRESS extern u64 of_translate_address(struct device_node *np, const __be32 *addr); +extern bool of_can_translate_address(struct device_node *dev); extern int of_address_to_resource(struct device_node *dev, int index, struct resource *r); extern struct device_node *of_find_matching_node_by_address( -- cgit v1.2.3