driver core: platform_bus: allow runtime override of dev_pm_ops

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: Magnus Damm <magnus.damm@gmail.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

driver core: platform_bus: allow runtime override of dev_pm_ops
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: Magnus Damm <magnus.damm@gmail.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Kevin Hilman · Greg Kroah-Hartman
1 parent 1037246cac
Showing 2 changed files with 38 additions and 0 deletions Side-by-side Diff
drivers/base/platform.c
include/linux/platform_device.h
@@ -976,6 +976,41 @@
 };
 EXPORT_SYMBOL_GPL(platform_bus_type);
  
+/**
+ * platform_bus_get_pm_ops() - return pointer to busses dev_pm_ops
+ *
+ * This function can be used by platform code to get the current
+ * set of dev_pm_ops functions used by the platform_bus_type.
+ */
+const struct dev_pm_ops * __init platform_bus_get_pm_ops(void)
+{
+	return platform_bus_type.pm;
+}
+
+/**
+ * platform_bus_set_pm_ops() - update dev_pm_ops for the platform_bus_type
+ *
+ * @pm: pointer to new dev_pm_ops struct to be used for platform_bus_type
+ *
+ * Platform code can override the dev_pm_ops methods of
+ * platform_bus_type by using this function.  It is expected that
+ * platform code will first do a platform_bus_get_pm_ops(), then
+ * kmemdup it, then customize selected methods and pass a pointer to
+ * the new struct dev_pm_ops to this function.
+ *
+ * Since platform-specific code is customizing methods for *all*
+ * devices (not just platform-specific devices) it is expected that
+ * any custom overrides of these functions will keep existing behavior
+ * and simply extend it.  For example, any customization of the
+ * runtime PM methods should continue to call the pm_generic_*
+ * functions as the default ones do in addition to the
+ * platform-specific behavior.
+ */
+void __init platform_bus_set_pm_ops(const struct dev_pm_ops *pm)
+{
+	platform_bus_type.pm = pm;
+}
+
 int __init platform_bus_init(void)
 {
 	int error;
@@ -138,6 +138,9 @@
 					struct resource *res, unsigned int n_res,
 					const void *data, size_t size);
  
+extern const struct dev_pm_ops * platform_bus_get_pm_ops(void);
+extern void platform_bus_set_pm_ops(const struct dev_pm_ops *pm);
+
 /* early platform driver interface */
 struct early_platform_driver {
 	const char *class_str;
...	...	@@ -976,6 +976,41 @@
976	976	};
977	977	EXPORT_SYMBOL_GPL(platform_bus_type);
978	978
	979	+/**
	980	+ * platform_bus_get_pm_ops() - return pointer to busses dev_pm_ops
	981	+ *
	982	+ * This function can be used by platform code to get the current
	983	+ * set of dev_pm_ops functions used by the platform_bus_type.
	984	+ */
	985	+const struct dev_pm_ops * __init platform_bus_get_pm_ops(void)
	986	+{
	987	+ return platform_bus_type.pm;
	988	+}
	989	+
	990	+/**
	991	+ * platform_bus_set_pm_ops() - update dev_pm_ops for the platform_bus_type
	992	+ *
	993	+ * @pm: pointer to new dev_pm_ops struct to be used for platform_bus_type
	994	+ *
	995	+ * Platform code can override the dev_pm_ops methods of
	996	+ * platform_bus_type by using this function. It is expected that
	997	+ * platform code will first do a platform_bus_get_pm_ops(), then
	998	+ * kmemdup it, then customize selected methods and pass a pointer to
	999	+ * the new struct dev_pm_ops to this function.
	1000	+ *
	1001	+ * Since platform-specific code is customizing methods for all
	1002	+ * devices (not just platform-specific devices) it is expected that
	1003	+ * any custom overrides of these functions will keep existing behavior
	1004	+ * and simply extend it. For example, any customization of the
	1005	+ * runtime PM methods should continue to call the pm_generic_*
	1006	+ * functions as the default ones do in addition to the
	1007	+ * platform-specific behavior.
	1008	+ */
	1009	+void __init platform_bus_set_pm_ops(const struct dev_pm_ops *pm)
	1010	+{
	1011	+ platform_bus_type.pm = pm;
	1012	+}
	1013	+
979	1014	int __init platform_bus_init(void)
980	1015	{
981	1016	int error;
...	...	@@ -138,6 +138,9 @@
138	138	struct resource *res, unsigned int n_res,
139	139	const void *data, size_t size);
140	140
	141	+extern const struct dev_pm_ops * platform_bus_get_pm_ops(void);
	142	+extern void platform_bus_set_pm_ops(const struct dev_pm_ops *pm);
	143	+
141	144	/* early platform driver interface */
142	145	struct early_platform_driver {
143	146	const char *class_str;