[RFC] early init and DT platform devices allocation/registration
Hiroshi Doyu
hdoyu at nvidia.com
Fri Jun 28 18:49:15 EST 2013
Grant Likely <grant.likely at secretlab.ca> wrote @ Wed, 26 Jun 2013 12:03:20 +0200:
> On Wed, Jun 26, 2013 at 7:00 AM, Hiroshi Doyu <hdoyu at nvidia.com> wrote:
> > Grant Likely <grant.likely at secretlab.ca> wrote @ Tue, 25 Jun 2013 19:52:33 +0200:
> >
> >> > Here's my workaround. I need to call of_detach_node() with OF_DYNAMIC
> >> > to avoid duplicated device registration.
> >>
> >> Gah! my eyes!
> >>
> >> Don't do that. It is incredibly problematic. Look at inhibiting
> >> duplicate device creation instead.
> >
> > I may not follow this thread correctly, but could anyone point out the
> > above "inhibiting duplicate device creation" if there's already such
> > solution?
>
> No, the solution doesn't exist yet, but it wouldn't be hard to
> implement. What you need to do is to add a struct device pointer to
> struct device_node, and set the pointer to the struct device when
> of_platform_device_create creates a device. (it would also need to be
> set for early_platform_device creation, but that's not something that
> should affect you). You would also add a check to
> of_platform_device_create to check if the device pointer is already
> set. If it is, then skip creation of the device.
Implemented as Grant suggested. At least this works for our case,
where IOMMU needs to be instanciated earlier than other device[1].
early_platform_device case still need to be covered.
[1] https://lists.ozlabs.org/pipermail/devicetree-discuss/2013-June/036685.html
>From da563c72f7fc37fedd4b7e3a957f41a484a19788 Mon Sep 17 00:00:00 2001
From: Hiroshi Doyu <hdoyu at nvidia.com>
Date: Fri, 28 Jun 2013 11:43:20 +0300
Subject: [PATCH RFC 1/1] of: dev_node has struct device pointer
To prevent of_platform_populate() from trying to populate duplicate
devices if a device has been already populated.
Signed-off-by: Hiroshi Doyu <hdoyu at nvidia.com>
---
drivers/of/base.c | 23 +++++++++++++++++++++++
drivers/of/platform.c | 8 ++++++++
include/linux/of.h | 16 ++++++++++++++++
3 files changed, 47 insertions(+)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 5c54279..99062dd 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -230,6 +230,29 @@ const void *of_get_property(const struct device_node *np, const char *name,
}
EXPORT_SYMBOL(of_get_property);
+struct device *of_get_device(const struct device_node *node)
+{
+ struct device *dev;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&devtree_lock, flags);
+ dev = node->dev;
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+ return dev;
+}
+EXPORT_SYMBOL(of_get_device);
+
+void of_set_device(struct device_node *node, struct device *dev)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&devtree_lock, flags);
+ node->dev = dev;
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+}
+EXPORT_SYMBOL(of_set_device);
+
/** Checks if the given "compat" string matches one of the strings in
* the device's "compatible" property
*/
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index e0a6514..a8f6b09 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -203,10 +203,17 @@ struct platform_device *of_platform_device_create_pdata(
struct device *parent)
{
struct platform_device *dev;
+ struct device *tmp;
if (!of_device_is_available(np))
return NULL;
+ tmp = of_get_device(np);
+ if (tmp) {
+ dev_info(tmp, "Already populated\n");
+ return to_platform_device(tmp);
+ }
+
dev = of_device_alloc(np, bus_id, parent);
if (!dev)
return NULL;
@@ -228,6 +235,7 @@ struct platform_device *of_platform_device_create_pdata(
return NULL;
}
+ of_set_device(np, &dev->dev);
return dev;
}
diff --git a/include/linux/of.h b/include/linux/of.h
index 1fd08ca..b548522 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -60,6 +60,9 @@ struct device_node {
struct kref kref;
unsigned long _flags;
void *data;
+
+ struct device *dev; /* Set only after populated */
+
#if defined(CONFIG_SPARC)
const char *path_component_name;
unsigned int unique_id;
@@ -268,6 +271,8 @@ extern const void *of_get_property(const struct device_node *node,
int *lenp);
#define for_each_property_of_node(dn, pp) \
for (pp = dn->properties; pp != NULL; pp = pp->next)
+extern struct device *of_get_device(const struct device_node *node);
+extern void of_set_device(struct device_node *node, struct device *dev);
extern int of_n_addr_cells(struct device_node *np);
extern int of_n_size_cells(struct device_node *np);
@@ -459,6 +464,17 @@ static inline const void *of_get_property(const struct device_node *node,
return NULL;
}
+static inline struct device *of_get_device(const struct device_node *node)
+{
+ return NULL;
+}
+
+static inline void of_set_device(const struct device_node *node,
+ struct device *dev);
+{
+ return -ENOSYS;
+}
+
static inline int of_property_read_u64(const struct device_node *np,
const char *propname, u64 *out_value)
{
--
1.7.9.5
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