| Message ID | 1360776872-18584-3-git-send-email-p.zabel@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Feb 13, 2013 at 06:34:26PM +0100, Philipp Zabel wrote: > This adds a simple API for devices to request being reset > by separate reset controller hardware and implements the > reset signal device tree binding. > > Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> > Reviewed-by: Stephen Warren <swarren@nvidia.com> > --- > Changes since v1: > - Added missing header files. > - Fixed reset_controller_register comment. > - Added missing reset_controller_unregister. > - Made reset_control_reset/assert/deassert return -ENOSYS > if not implemented by the reset controller driver. > - Fixed reset_control_put to not access rstc after freeing it. > - Whitespace fixes > --- > drivers/Kconfig | 2 + > drivers/Makefile | 3 + > drivers/reset/Kconfig | 9 ++ > drivers/reset/Makefile | 1 + > drivers/reset/core.c | 238 ++++++++++++++++++++++++++++++++++++++ > include/linux/reset-controller.h | 39 +++++++ > include/linux/reset.h | 17 +++ > 7 files changed, 309 insertions(+) > create mode 100644 drivers/reset/Kconfig > create mode 100644 drivers/reset/Makefile > create mode 100644 drivers/reset/core.c > create mode 100644 include/linux/reset-controller.h > create mode 100644 include/linux/reset.h > > diff --git a/drivers/Kconfig b/drivers/Kconfig > index 202fa6d..847f8e3 100644 > --- a/drivers/Kconfig > +++ b/drivers/Kconfig > @@ -162,4 +162,6 @@ source "drivers/irqchip/Kconfig" > > source "drivers/ipack/Kconfig" > > +source "drivers/reset/Kconfig" > + > endmenu > diff --git a/drivers/Makefile b/drivers/Makefile > index 4af933d..682fb7c 100644 > --- a/drivers/Makefile > +++ b/drivers/Makefile > @@ -42,6 +42,9 @@ ifndef CONFIG_ARCH_USES_GETTIMEOFFSET > obj-y += clocksource/ > endif > > +# reset controllers early, since gpu drivers might rely on them to initialize > +obj-$(CONFIG_RESET_CONTROLLER) += reset/ > + > # tty/ comes before char/ so that the VT console is the boot-time > # default. > obj-y += tty/ > diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig > new file mode 100644 > index 0000000..66ac385 > --- /dev/null > +++ b/drivers/reset/Kconfig > @@ -0,0 +1,9 @@ > +menuconfig RESET_CONTROLLER > + bool "Reset Controller Support" > + help > + Generic Reset Controller support. > + > + This framework is designed to abstract reset handling of devices > + via GPIOs or SoC-internal reset controller modules. > + > + If unsure, say no. > diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile > new file mode 100644 > index 0000000..1e2d83f > --- /dev/null > +++ b/drivers/reset/Makefile > @@ -0,0 +1 @@ > +obj-$(CONFIG_RESET_CONTROLLER) += core.o > diff --git a/drivers/reset/core.c b/drivers/reset/core.c > new file mode 100644 > index 0000000..468f831 > --- /dev/null > +++ b/drivers/reset/core.c > @@ -0,0 +1,238 @@ > +#include <linux/device.h> > +#include <linux/err.h> > +#include <linux/export.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/reset.h> > +#include <linux/reset-controller.h> > +#include <linux/slab.h> > + > +static DEFINE_MUTEX(reset_controller_list_mutex); > +static LIST_HEAD(reset_controller_list); > + > +/** > + * struct reset_control - a reset control > + * I see two kerneldoc styles in the file. Some have new lines here while others do not. And @rcdev is missing. > + * @id: ID of the reset controller in the reset > + * controller device > + */ > +struct reset_control { > + struct reset_controller_dev *rcdev; > + unsigned int id; > +}; > + > +/** > + * reset_controller_register - register a reset controller device > + * > + * @rcdev: a pointer to struct reset_controller_dev > + */ > +int reset_controller_register(struct reset_controller_dev *rcdev) > +{ > + mutex_lock(&reset_controller_list_mutex); > + list_add(&rcdev->list, &reset_controller_list); > + mutex_unlock(&reset_controller_list_mutex); > + > + return 0; > +} I think we need EXPORT_SYMBOL_GPL on it, as the gpio-reset driver added in patch #8 which supports module build will need it. > + > +/** > + * reset_controller_unregister - unregister a reset controller device > + * > + * @rcdev: a pointer to struct reset_controller_dev > + */ > +void reset_controller_unregister(struct reset_controller_dev *rcdev) > +{ > + mutex_lock(&reset_controller_list_mutex); > + list_del(&rcdev->list); > + mutex_unlock(&reset_controller_list_mutex); > +} Ditto > + > +/** > + * reset_control_reset - reset the controlled device > + * @rstc: reset controller > + */ > +int reset_control_reset(struct reset_control *rstc) > +{ > + if (rstc->rcdev->ops->reset) > + return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); > + > + return -ENOSYS; > +} > +EXPORT_SYMBOL_GPL(reset_control_reset); > + > +/** > + * reset_control_assert - asserts the reset line > + * @rstc: reset controller > + */ > +int reset_control_assert(struct reset_control *rstc) > +{ > + if (rstc->rcdev->ops->assert) > + return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); > + > + return -ENOSYS; > +} > +EXPORT_SYMBOL_GPL(reset_control_assert); > + > +/** > + * reset_control_deassert - deasserts the reset line > + * @rstc: reset controller > + */ > +int reset_control_deassert(struct reset_control *rstc) > +{ > + if (rstc->rcdev->ops->deassert) > + return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); > + > + return -ENOSYS; > +} > +EXPORT_SYMBOL_GPL(reset_control_deassert); > + > +/** > + * reset_control_get - Lookup and obtain a reference to a reset controller. > + * @dev: device to be reset by the controller > + * @id: reset line name > + * > + * Returns a struct reset_control or IS_ERR() condition containing errno. > + * > + * Use of id names is optional. > + */ > +struct reset_control *reset_control_get(struct device *dev, const char *id) > +{ > + struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER); > + struct reset_controller_dev *r, *rcdev; > + struct device_node *rcdev_node; > + struct of_phandle_args args; > + int rcdev_index; > + int ret; > + int i; > + > + if (!dev) > + return ERR_PTR(-EINVAL); > + > + rcdev_node = NULL; > + for (i = 0; rcdev_node == NULL; i++) { > + ret = of_parse_phandle_with_args(dev->of_node, "resets", > + "#reset-cells", i, &args); > + if (ret) > + return ERR_PTR(ret); > + of_node_put(args.np); > + if (args.args_count <= 0) > + return ERR_PTR(-EINVAL); > + > + if (id) { > + const char *reset_name; > + ret = of_property_read_string_index(dev->of_node, > + "reset-names", i, > + &reset_name); > + if (ret) > + return ERR_PTR(ret); > + if (strcmp(id, reset_name) != 0) > + continue; > + } > + > + rcdev_index = args.args[0]; > + rcdev_node = args.np; > + break; > + } I feel the block could be simplified a little bit by calling of_property_match_string(dev->of_node, "reset-names", id) to find the index that is needed by of_parse_phandle_with_args() call. You might want to take a look at of_clk_get_by_name() - drivers/clk/clkdev.c for example. > + > + mutex_lock(&reset_controller_list_mutex); > + rcdev = NULL; > + list_for_each_entry(r, &reset_controller_list, list) { > + if (rcdev_node == r->of_node) { > + rcdev = r; > + break; > + } > + } > + mutex_unlock(&reset_controller_list_mutex); > + > + if (!rcdev) > + return ERR_PTR(-ENODEV); > + > + try_module_get(rcdev->owner); > + > + rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); > + if (!rstc) > + return ERR_PTR(-ENOMEM); > + > + rstc->rcdev = rcdev; > + rstc->id = rcdev_index; > + > + return rstc; > +} > +EXPORT_SYMBOL_GPL(reset_control_get); > + > +/** > + * reset_control_put - free the reset controller > + * @reset: reset controller @rstc, not @reset. > + */ > + > +void reset_control_put(struct reset_control *rstc) > +{ > + if (IS_ERR(rstc)) > + return; > + > + module_put(rstc->rcdev->owner); > + kfree(rstc); > +} > +EXPORT_SYMBOL_GPL(reset_control_put); > + > +static void devm_reset_control_release(struct device *dev, void *res) > +{ > + reset_control_put(*(struct reset_control **)res); > +} > + > +/** > + * devm_reset_control_get - resource managed reset_control_get() > + * @dev: device to be reset by the controller > + * @id: reset line name > + * > + * Managed reset_control_get(). For reset controllers returned from this > + * function, reset_control_put() is called automatically on driver detach. > + * See reset_control_get() for more information. > + */ > +struct reset_control *devm_reset_control_get(struct device *dev, const char *id) > +{ > + struct reset_control **ptr, *rstc; > + > + ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), > + GFP_KERNEL); > + if (!ptr) > + return ERR_PTR(-ENOMEM); > + > + rstc = reset_control_get(dev, id); > + if (!IS_ERR(rstc)) { > + *ptr = rstc; > + devres_add(dev, ptr); > + } else { > + devres_free(ptr); > + } > + > + return rstc; > +} > +EXPORT_SYMBOL_GPL(devm_reset_control_get); > + > +/** > + * device_reset - find reset controller associated with the device > + * and perform reset > + * @dev: device to be reset by the controller > + * > + * Convenience wrapper for reset_control_get() and reset_control_reset(). > + * This is useful for the common case of devices with single, dedicated reset > + * lines. > + */ > +int device_reset(struct device *dev) > +{ > + struct reset_control *rstc; > + int ret; > + > + rstc = reset_control_get(dev, NULL); > + if (IS_ERR(rstc)) > + return PTR_ERR(rstc); > + > + ret = reset_control_reset(rstc); > + > + kfree(rstc); Shouldn't reset_control_put() be called here instead? > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(device_reset); > diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h > new file mode 100644 > index 0000000..4d38aa3 > --- /dev/null > +++ b/include/linux/reset-controller.h > @@ -0,0 +1,39 @@ > +#ifndef _LINUX_RESET_CONTROLLER_H_ > +#define _LINUX_RESET_CONTROLLER_H_ > + > +#include <linux/list.h> > + > +struct reset_controller_dev; > + > +/** > + * struct reset_control_ops > + * > + * @reset: for self-deasserting resets, does all necessary > + * things to reset the device > + * @assert: manually assert the reset line, if supported > + * @deassert: manually deassert the reset line, if supported > + */ > +struct reset_control_ops { > + int (*reset)(struct reset_controller_dev *rcdev, unsigned long id); > + int (*assert)(struct reset_controller_dev *rcdev, unsigned long id); > + int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id); > +}; > + > +struct module; > +struct device_node; > + > +/** > + * struct reset_controller - reset controller entity that might s/reset_controller/reset_controller_dev > + * provide multiple reset controls Kerneldoc of parameters are missing. Shawn > + */ > +struct reset_controller_dev { > + struct reset_control_ops *ops; > + struct module *owner; > + struct list_head list; > + struct device_node *of_node; > +}; > + > +int reset_controller_register(struct reset_controller_dev *rcdev); > +void reset_controller_unregister(struct reset_controller_dev *rcdev); > + > +#endif > diff --git a/include/linux/reset.h b/include/linux/reset.h > new file mode 100644 > index 0000000..c4119c5 > --- /dev/null > +++ b/include/linux/reset.h > @@ -0,0 +1,17 @@ > +#ifndef _LINUX_RESET_H_ > +#define _LINUX_RESET_H_ > + > +struct device; > +struct reset_control; > + > +int reset_control_reset(struct reset_control *rstc); > +int reset_control_assert(struct reset_control *rstc); > +int reset_control_deassert(struct reset_control *rstc); > + > +struct reset_control *reset_controlr_get(struct device *dev, const char *id); > +void reset_control_put(struct reset_control *rstc); > +struct reset_control *devm_reset_control_get(struct device *dev, const char *id); > + > +int device_reset(struct device *dev); > + > +#endif > -- > 1.7.10.4 >
diff --git a/drivers/Kconfig b/drivers/Kconfig index 202fa6d..847f8e3 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -162,4 +162,6 @@ source "drivers/irqchip/Kconfig" source "drivers/ipack/Kconfig" +source "drivers/reset/Kconfig" + endmenu diff --git a/drivers/Makefile b/drivers/Makefile index 4af933d..682fb7c 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -42,6 +42,9 @@ ifndef CONFIG_ARCH_USES_GETTIMEOFFSET obj-y += clocksource/ endif +# reset controllers early, since gpu drivers might rely on them to initialize +obj-$(CONFIG_RESET_CONTROLLER) += reset/ + # tty/ comes before char/ so that the VT console is the boot-time # default. obj-y += tty/ diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig new file mode 100644 index 0000000..66ac385 --- /dev/null +++ b/drivers/reset/Kconfig @@ -0,0 +1,9 @@ +menuconfig RESET_CONTROLLER + bool "Reset Controller Support" + help + Generic Reset Controller support. + + This framework is designed to abstract reset handling of devices + via GPIOs or SoC-internal reset controller modules. + + If unsure, say no. diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile new file mode 100644 index 0000000..1e2d83f --- /dev/null +++ b/drivers/reset/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_RESET_CONTROLLER) += core.o diff --git a/drivers/reset/core.c b/drivers/reset/core.c new file mode 100644 index 0000000..468f831 --- /dev/null +++ b/drivers/reset/core.c @@ -0,0 +1,238 @@ +#include <linux/device.h> +#include <linux/err.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/reset.h> +#include <linux/reset-controller.h> +#include <linux/slab.h> + +static DEFINE_MUTEX(reset_controller_list_mutex); +static LIST_HEAD(reset_controller_list); + +/** + * struct reset_control - a reset control + * + * @id: ID of the reset controller in the reset + * controller device + */ +struct reset_control { + struct reset_controller_dev *rcdev; + unsigned int id; +}; + +/** + * reset_controller_register - register a reset controller device + * + * @rcdev: a pointer to struct reset_controller_dev + */ +int reset_controller_register(struct reset_controller_dev *rcdev) +{ + mutex_lock(&reset_controller_list_mutex); + list_add(&rcdev->list, &reset_controller_list); + mutex_unlock(&reset_controller_list_mutex); + + return 0; +} + +/** + * reset_controller_unregister - unregister a reset controller device + * + * @rcdev: a pointer to struct reset_controller_dev + */ +void reset_controller_unregister(struct reset_controller_dev *rcdev) +{ + mutex_lock(&reset_controller_list_mutex); + list_del(&rcdev->list); + mutex_unlock(&reset_controller_list_mutex); +} + +/** + * reset_control_reset - reset the controlled device + * @rstc: reset controller + */ +int reset_control_reset(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->reset) + return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_reset); + +/** + * reset_control_assert - asserts the reset line + * @rstc: reset controller + */ +int reset_control_assert(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->assert) + return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_assert); + +/** + * reset_control_deassert - deasserts the reset line + * @rstc: reset controller + */ +int reset_control_deassert(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->deassert) + return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_deassert); + +/** + * reset_control_get - Lookup and obtain a reference to a reset controller. + * @dev: device to be reset by the controller + * @id: reset line name + * + * Returns a struct reset_control or IS_ERR() condition containing errno. + * + * Use of id names is optional. + */ +struct reset_control *reset_control_get(struct device *dev, const char *id) +{ + struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER); + struct reset_controller_dev *r, *rcdev; + struct device_node *rcdev_node; + struct of_phandle_args args; + int rcdev_index; + int ret; + int i; + + if (!dev) + return ERR_PTR(-EINVAL); + + rcdev_node = NULL; + for (i = 0; rcdev_node == NULL; i++) { + ret = of_parse_phandle_with_args(dev->of_node, "resets", + "#reset-cells", i, &args); + if (ret) + return ERR_PTR(ret); + of_node_put(args.np); + if (args.args_count <= 0) + return ERR_PTR(-EINVAL); + + if (id) { + const char *reset_name; + ret = of_property_read_string_index(dev->of_node, + "reset-names", i, + &reset_name); + if (ret) + return ERR_PTR(ret); + if (strcmp(id, reset_name) != 0) + continue; + } + + rcdev_index = args.args[0]; + rcdev_node = args.np; + break; + } + + mutex_lock(&reset_controller_list_mutex); + rcdev = NULL; + list_for_each_entry(r, &reset_controller_list, list) { + if (rcdev_node == r->of_node) { + rcdev = r; + break; + } + } + mutex_unlock(&reset_controller_list_mutex); + + if (!rcdev) + return ERR_PTR(-ENODEV); + + try_module_get(rcdev->owner); + + rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); + if (!rstc) + return ERR_PTR(-ENOMEM); + + rstc->rcdev = rcdev; + rstc->id = rcdev_index; + + return rstc; +} +EXPORT_SYMBOL_GPL(reset_control_get); + +/** + * reset_control_put - free the reset controller + * @reset: reset controller + */ + +void reset_control_put(struct reset_control *rstc) +{ + if (IS_ERR(rstc)) + return; + + module_put(rstc->rcdev->owner); + kfree(rstc); +} +EXPORT_SYMBOL_GPL(reset_control_put); + +static void devm_reset_control_release(struct device *dev, void *res) +{ + reset_control_put(*(struct reset_control **)res); +} + +/** + * devm_reset_control_get - resource managed reset_control_get() + * @dev: device to be reset by the controller + * @id: reset line name + * + * Managed reset_control_get(). For reset controllers returned from this + * function, reset_control_put() is called automatically on driver detach. + * See reset_control_get() for more information. + */ +struct reset_control *devm_reset_control_get(struct device *dev, const char *id) +{ + struct reset_control **ptr, *rstc; + + ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), + GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + rstc = reset_control_get(dev, id); + if (!IS_ERR(rstc)) { + *ptr = rstc; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return rstc; +} +EXPORT_SYMBOL_GPL(devm_reset_control_get); + +/** + * device_reset - find reset controller associated with the device + * and perform reset + * @dev: device to be reset by the controller + * + * Convenience wrapper for reset_control_get() and reset_control_reset(). + * This is useful for the common case of devices with single, dedicated reset + * lines. + */ +int device_reset(struct device *dev) +{ + struct reset_control *rstc; + int ret; + + rstc = reset_control_get(dev, NULL); + if (IS_ERR(rstc)) + return PTR_ERR(rstc); + + ret = reset_control_reset(rstc); + + kfree(rstc); + + return ret; +} +EXPORT_SYMBOL_GPL(device_reset); diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h new file mode 100644 index 0000000..4d38aa3 --- /dev/null +++ b/include/linux/reset-controller.h @@ -0,0 +1,39 @@ +#ifndef _LINUX_RESET_CONTROLLER_H_ +#define _LINUX_RESET_CONTROLLER_H_ + +#include <linux/list.h> + +struct reset_controller_dev; + +/** + * struct reset_control_ops + * + * @reset: for self-deasserting resets, does all necessary + * things to reset the device + * @assert: manually assert the reset line, if supported + * @deassert: manually deassert the reset line, if supported + */ +struct reset_control_ops { + int (*reset)(struct reset_controller_dev *rcdev, unsigned long id); + int (*assert)(struct reset_controller_dev *rcdev, unsigned long id); + int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id); +}; + +struct module; +struct device_node; + +/** + * struct reset_controller - reset controller entity that might + * provide multiple reset controls + */ +struct reset_controller_dev { + struct reset_control_ops *ops; + struct module *owner; + struct list_head list; + struct device_node *of_node; +}; + +int reset_controller_register(struct reset_controller_dev *rcdev); +void reset_controller_unregister(struct reset_controller_dev *rcdev); + +#endif diff --git a/include/linux/reset.h b/include/linux/reset.h new file mode 100644 index 0000000..c4119c5 --- /dev/null +++ b/include/linux/reset.h @@ -0,0 +1,17 @@ +#ifndef _LINUX_RESET_H_ +#define _LINUX_RESET_H_ + +struct device; +struct reset_control; + +int reset_control_reset(struct reset_control *rstc); +int reset_control_assert(struct reset_control *rstc); +int reset_control_deassert(struct reset_control *rstc); + +struct reset_control *reset_controlr_get(struct device *dev, const char *id); +void reset_control_put(struct reset_control *rstc); +struct reset_control *devm_reset_control_get(struct device *dev, const char *id); + +int device_reset(struct device *dev); + +#endif