From: Kevin Hilman <[email protected]>
Currently, the platform_bus allows customization of several of the
busses dev_pm_ops methods by using weak symbols so that platform code
can override them. The weak-symbol approach is not scalable when
wanting to support multiple platforms in a single kernel binary.
Instead, provide __init methods for platform code to customize the
dev_pm_ops methods at runtime.
NOTE: after these dynamic methods are merged, the weak symbols should
be removed from drivers/base/platform.c. AFAIK, this will only
affect SH and sh-mobile which should be converted to use this
runtime approach instead of the weak symbols. After SH &
sh-mobile are converted, the weak symobols could be removed.
Tested on OMAP3.
Cc: Grant Likely <[email protected]>
Cc: Magnus Damm <[email protected]>
Signed-off-by: Kevin Hilman <[email protected]>
---
drivers/base/platform.c | 16 ++++++++++++++++
include/linux/platform_device.h | 3 +++
2 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index c6c933f..a7d8a00 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -976,6 +976,22 @@ struct bus_type platform_bus_type = {
};
EXPORT_SYMBOL_GPL(platform_bus_type);
+const struct dev_pm_ops * __init platform_bus_get_pm_ops(void)
+{
+ struct bus_type *bus = &platform_bus_type;
+
+ return bus->pm;
+}
+
+int __init platform_bus_set_pm_ops(struct dev_pm_ops *pm)
+{
+ struct bus_type *bus = &platform_bus_type;
+
+ bus->pm = pm;
+
+ return 0;
+}
+
int __init platform_bus_init(void)
{
int error;
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index d7ecad0..4bce2c9 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -138,6 +138,9 @@ extern struct platform_device *platform_create_bundle(struct platform_driver *dr
struct resource *res, unsigned int n_res,
const void *data, size_t size);
+extern const struct dev_pm_ops * __init platform_bus_get_pm_ops(void);
+extern int __init platform_bus_set_pm_ops(struct dev_pm_ops *pm);
+
/* early platform driver interface */
struct early_platform_driver {
const char *class_str;
--
1.7.2.1
"Kevin Hilman" <[email protected]> wrote:
>From: Kevin Hilman <[email protected]>
>
>Currently, the platform_bus allows customization of several of the
>busses dev_pm_ops methods by using weak symbols so that platform code
>can override them. The weak-symbol approach is not scalable when
>wanting to support multiple platforms in a single kernel binary.
>
>Instead, provide __init methods for platform code to customize the
>dev_pm_ops methods at runtime.
>
>NOTE: after these dynamic methods are merged, the weak symbols should
> be removed from drivers/base/platform.c. AFAIK, this will only
> affect SH and sh-mobile which should be converted to use this
> runtime approach instead of the weak symbols. After SH &
> sh-mobile are converted, the weak symobols could be removed.
>
>Tested on OMAP3.
>
>Cc: Grant Likely <[email protected]>
>Cc: Magnus Damm <[email protected]>
>Signed-off-by: Kevin Hilman <[email protected]>
>---
> drivers/base/platform.c | 16 ++++++++++++++++
> include/linux/platform_device.h | 3 +++
> 2 files changed, 19 insertions(+), 0 deletions(-)
>
>diff --git a/drivers/base/platform.c b/drivers/base/platform.c
>index c6c933f..a7d8a00 100644
>--- a/drivers/base/platform.c
>+++ b/drivers/base/platform.c
>@@ -976,6 +976,22 @@ struct bus_type platform_bus_type = {
> };
> EXPORT_SYMBOL_GPL(platform_bus_type);
>
>+const struct dev_pm_ops * __init platform_bus_get_pm_ops(void)
>+{
>+ struct bus_type *bus = &platform_bus_type;
>+
>+ return bus->pm;
>+}
>+
>+int __init platform_bus_set_pm_ops(struct dev_pm_ops *pm)
>+{
>+ struct bus_type *bus = &platform_bus_type;
>+
>+ bus->pm = pm;
>+
>+ return 0;
>+}
>+
Looks okay to me, but these functions should have kerneldoc headers describing what they are, and more importantly, the constraints and what the acceptable use case is.
g.
> int __init platform_bus_init(void)
> {
> int error;
>diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
>index d7ecad0..4bce2c9 100644
>--- a/include/linux/platform_device.h
>+++ b/include/linux/platform_device.h
>@@ -138,6 +138,9 @@ extern struct platform_device *platform_create_bundle(struct platform_driver *dr
> struct resource *res, unsigned int n_res,
> const void *data, size_t size);
>
>+extern const struct dev_pm_ops * __init platform_bus_get_pm_ops(void);
>+extern int __init platform_bus_set_pm_ops(struct dev_pm_ops *pm);
>+
> /* early platform driver interface */
> struct early_platform_driver {
> const char *class_str;
>--
>1.7.2.1
>
--
Sent from my Android phone with K-9 Mail. Please excuse my brevity.
"Grant Likely" <[email protected]> wrote:
>
>
>"Kevin Hilman" <[email protected]> wrote:
>
>>From: Kevin Hilman <[email protected]>
>>
>>Currently, the platform_bus allows customization of several of the
>>busses dev_pm_ops methods by using weak symbols so that platform code
>>can override them. The weak-symbol approach is not scalable when
>>wanting to support multiple platforms in a single kernel binary.
>>
>>Instead, provide __init methods for platform code to customize the
>>dev_pm_ops methods at runtime.
>>
>>NOTE: after these dynamic methods are merged, the weak symbols should
>> be removed from drivers/base/platform.c. AFAIK, this will only
>> affect SH and sh-mobile which should be converted to use this
>> runtime approach instead of the weak symbols. After SH &
>> sh-mobile are converted, the weak symobols could be removed.
>>
>>Tested on OMAP3.
>>
>>Cc: Grant Likely <[email protected]>
>>Cc: Magnus Damm <[email protected]>
>>Signed-off-by: Kevin Hilman <[email protected]>
>>---
>> drivers/base/platform.c | 16 ++++++++++++++++
>> include/linux/platform_device.h | 3 +++
>> 2 files changed, 19 insertions(+), 0 deletions(-)
>>
>>diff --git a/drivers/base/platform.c b/drivers/base/platform.c
>>index c6c933f..a7d8a00 100644
>>--- a/drivers/base/platform.c
>>+++ b/drivers/base/platform.c
>>@@ -976,6 +976,22 @@ struct bus_type platform_bus_type = {
>> };
>> EXPORT_SYMBOL_GPL(platform_bus_type);
>>
>>+const struct dev_pm_ops * __init platform_bus_get_pm_ops(void)
>>+{
>>+ struct bus_type *bus = &platform_bus_type;
>>+
>>+ return bus->pm;
>>+}
>>+
>>+int __init platform_bus_set_pm_ops(struct dev_pm_ops *pm)
>>+{
>>+ struct bus_type *bus = &platform_bus_type;
>>+
>>+ bus->pm = pm;
>>+
>>+ return 0;
>>+}
>>+
Another (minor) note, these can be more concise. The set open function can have a void return, and bus = &platform_bus_type lines are unnecessary.
g.
>--
>Sent from my Android phone with K-9 Mail. Please excuse my brevity.
--
Sent from my Android phone with K-9 Mail. Please excuse my brevity.