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of: Allow busses with #size-cells=0

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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>
This commit is contained in:
Stephen Warren 2012-07-25 17:34:37 -06:00 committed by Rob Herring
parent 0d7614f09c
commit 5d61b165c8
3 changed files with 37 additions and 7 deletions
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27
drivers/of/address.c
View File

@ -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 @@ const __be32 *of_get_pci_address(struct device_node *dev, int bar_no, u64 *size,
}
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 @@ u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
}
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 @@ const __be32 *of_get_address(struct device_node *dev, int index, u64 *size,
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 */

10
drivers/of/platform.c
View File

@ -78,6 +78,7 @@ void of_device_make_bus_id(struct device *dev)
struct device_node *node = dev->of_node;
const u32 *reg;
u64 addr;
const __be32 *addrp;
int magic;
#ifdef CONFIG_PPC_DCR
@ -105,7 +106,15 @@ void of_device_make_bus_id(struct device *dev)
*/
reg = of_get_property(node, "reg", NULL);
if (reg) {
if (of_can_translate_address(node)) {
addr = of_translate_address(node, reg);
} else {
addrp = of_get_address(node, 0, NULL, NULL);
if (addrp)
addr = of_read_number(addrp, 1);
else
addr = OF_BAD_ADDR;
}
if (addr != OF_BAD_ADDR) {
dev_set_name(dev, "%llx.%s",
(unsigned long long)addr, node->name);
@ -140,6 +149,7 @@ struct platform_device *of_device_alloc(struct device_node *np,
return NULL;
/* count the io and irq resources */
if (of_can_translate_address(np))
while (of_address_to_resource(np, num_reg, &temp_res) == 0)
num_reg++;
num_irq = of_irq_count(np);

1
include/linux/of_address.h
View File

@ -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(