diff options
| author | Stephen Warren <swarren@nvidia.com> | 2012-07-25 17:34:37 -0600 |
|---|---|---|
| committer | Rob Herring <rob.herring@calxeda.com> | 2012-08-03 08:01:46 -0500 |
| commit | 5d61b165c892853f2daf6220d2ec6577487e273a (patch) | |
| tree | 3bcff9b185383c768b702461c1194cb8eb9d0002 /include/linux/of_address.h | |
| parent | 0d7614f09c1ebdbaa1599a5aba7593f147bf96ee (diff) | |
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.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/of_address.h b/include/linux/of_address.h index 01b925ad8d7..c3cdc1025c3 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( |