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>
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 7e262a6..7a07751 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -9,8 +9,8 @@
/* Max address size we deal with */
#define OF_MAX_ADDR_CELLS 4
-#define OF_CHECK_COUNTS(na, ns) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS && \
- (ns) > 0)
+#define OF_CHECK_ADDR_COUNT(na) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS)
+#define OF_CHECK_COUNTS(na, ns) (OF_CHECK_ADDR_COUNT(na) && (ns) > 0)
static struct of_bus *of_match_bus(struct device_node *np);
static int __of_address_to_resource(struct device_node *dev,
@@ -182,7 +182,7 @@
}
bus->count_cells(dev, &na, &ns);
of_node_put(parent);
- if (!OF_CHECK_COUNTS(na, ns))
+ if (!OF_CHECK_ADDR_COUNT(na))
return NULL;
/* Get "reg" or "assigned-addresses" property */
@@ -490,6 +490,25 @@
}
EXPORT_SYMBOL(of_translate_dma_address);
+bool of_can_translate_address(struct device_node *dev)
+{
+ struct device_node *parent;
+ struct of_bus *bus;
+ int na, ns;
+
+ parent = of_get_parent(dev);
+ if (parent == NULL)
+ return false;
+
+ bus = of_match_bus(parent);
+ bus->count_cells(dev, &na, &ns);
+
+ of_node_put(parent);
+
+ return OF_CHECK_COUNTS(na, ns);
+}
+EXPORT_SYMBOL(of_can_translate_address);
+
const __be32 *of_get_address(struct device_node *dev, int index, u64 *size,
unsigned int *flags)
{
@@ -506,7 +525,7 @@
bus = of_match_bus(parent);
bus->count_cells(dev, &na, &ns);
of_node_put(parent);
- if (!OF_CHECK_COUNTS(na, ns))
+ if (!OF_CHECK_ADDR_COUNT(na))
return NULL;
/* Get "reg" or "assigned-addresses" property */