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authorStephen Warren <swarren@nvidia.com>2012-07-26 03:34:37 +0400
committerRob Herring <rob.herring@calxeda.com>2012-08-03 17:01:46 +0400
commit5d61b165c892853f2daf6220d2ec6577487e273a (patch)
tree3bcff9b185383c768b702461c1194cb8eb9d0002 /include/linux/of_address.h
parent0d7614f09c1ebdbaa1599a5aba7593f147bf96ee (diff)
downloadlinux-5d61b165c892853f2daf6220d2ec6577487e273a.tar.xz
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 <swarren@nvidia.com> Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Diffstat (limited to 'include/linux/of_address.h')
-rw-r--r--include/linux/of_address.h1
1 files changed, 1 insertions, 0 deletions
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(