| Message ID | 1282583922-984-1-git-send-email-khilman@deeprootsystems.com |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mon, Aug 23, 2010 at 11:18 AM, Kevin Hilman <khilman@deeprootsystems.com> wrote: > 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 <grant.likely@secretlab.ca> > Cc: Magnus Damm <magnus.damm@gmail.com> > Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Looks good to me. A handful of nitpicks below, I don't know if Greg will want you to respin for these or not. Feel free to add my acked-by line though: Acked-by: Grant Likely <grant.likely@secretlab.ca> > --- > drivers/base/platform.c | 35 +++++++++++++++++++++++++++++++++++ > include/linux/platform_device.h | 3 +++ > 2 files changed, 38 insertions(+), 0 deletions(-) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index c6c933f..e40a773 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -976,6 +976,41 @@ struct bus_type platform_bus_type = { > }; > EXPORT_SYMBOL_GPL(platform_bus_type); > > +/** > + * platform_bus_get_pm_ops: return pointer to busses dev_pm_ops Nit: first line of kerneldoc format should look like this: /** * 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(struct dev_pm_ops *pm) nit: const struct dev_pm_ops would be appropriate > +{ > + platform_bus_type.pm = pm; > +} > + > int __init platform_bus_init(void) > { > int error; > diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h > index d7ecad0..cd55d39 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 void __init platform_bus_set_pm_ops(struct dev_pm_ops *pm); The __init annotations should only appear in the .c file, not the header. Cheers, g. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/base/platform.c b/drivers/base/platform.c index c6c933f..e40a773 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -976,6 +976,41 @@ struct bus_type platform_bus_type = { }; 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(struct dev_pm_ops *pm) +{ + platform_bus_type.pm = pm; +} + int __init platform_bus_init(void) { int error; diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index d7ecad0..cd55d39 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 void __init platform_bus_set_pm_ops(struct dev_pm_ops *pm); + /* early platform driver interface */ struct early_platform_driver { const char *class_str;
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 <grant.likely@secretlab.ca> Cc: Magnus Damm <magnus.damm@gmail.com> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> --- drivers/base/platform.c | 35 +++++++++++++++++++++++++++++++++++ include/linux/platform_device.h | 3 +++ 2 files changed, 38 insertions(+), 0 deletions(-)