In "Device Tree powered" systems, platform devices are usually
massively populated with of_platform_populate() call, executed
at some level of initcalls, either by generic architecture
or by platform-specific code.
There are situations though where certain devices must be
created (and bound with drivers) before all the others.
This presents a challenge, as devices created explicitly
would be created again by of_platform_populate().
This patch tries to solve that issue in a generic way,
adding a "populated" flag for a DT node description.
Once set, this device will never be created again via
of_* API, so of_platform_populate() will skip such nodes
(and its children) in a similar way to the non-available
ones.
Cc: devicetree@xxxxxxxxxxxxxxx
Signed-off-by: Pawel Moll <pawel.moll@xxxxxxx>
---
drivers/of/platform.c | 10 ++++++++--
include/linux/of.h | 1 +
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 404d1da..0ae757a 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -204,7 +204,8 @@ static struct platform_device *of_platform_device_create_pdata(
{
struct platform_device *dev;
- if (!of_device_is_available(np))
+ if (!of_device_is_available(np) ||
+ of_node_check_flag(np, OF_POPULATED))
return NULL;
dev = of_device_alloc(np, bus_id, parent);
@@ -230,6 +231,8 @@ static struct platform_device *of_platform_device_create_pdata(
return NULL;
}
+ of_node_set_flag(np, OF_POPULATED);
+
return dev;
}
@@ -262,7 +265,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
pr_debug("Creating amba device %s\n", node->full_name);
- if (!of_device_is_available(node))
+ if (!of_device_is_available(node) ||
+ of_node_check_flag(node, OF_POPULATED))
return NULL;
dev = amba_device_alloc(NULL, 0, 0);
@@ -305,6 +309,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
goto err_free;
}
+ of_node_set_flag(node, OF_POPULATED);
+
return dev;
err_free:
diff --git a/include/linux/of.h b/include/linux/of.h
index 3bad8d1..fd3aaee 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -197,6 +197,7 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size)
/* flag descriptions */
#define OF_DYNAMIC 1 /* node and properties were allocated via kmalloc */
#define OF_DETACHED 2 /* node has been detached from the device tree */
+#define OF_POPULATED 3 /* device already created for the node */
#define OF_IS_DYNAMIC(x) test_bit(OF_DYNAMIC, &x->_flags)
#define OF_MARK_DYNAMIC(x) set_bit(OF_DYNAMIC, &x->_flags)
--
1.9.1
--
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