diff options
Diffstat (limited to 'drivers/reset/core.c')
| -rw-r--r-- | drivers/reset/core.c | 1366 |
1 files changed, 1254 insertions, 112 deletions
diff --git a/drivers/reset/core.c b/drivers/reset/core.c index d1b6089a0ef8..0135dd0ae204 100644 --- a/drivers/reset/core.c +++ b/drivers/reset/core.c @@ -1,60 +1,121 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * Reset Controller framework * * Copyright 2013 Philipp Zabel, Pengutronix - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. */ + +#include <linux/acpi.h> +#include <linux/atomic.h> +#include <linux/auxiliary_bus.h> +#include <linux/cleanup.h> #include <linux/device.h> #include <linux/err.h> #include <linux/export.h> +#include <linux/gpio/driver.h> +#include <linux/gpio/machine.h> +#include <linux/gpio/property.h> +#include <linux/idr.h> #include <linux/kernel.h> +#include <linux/kref.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 DEFINE_MUTEX(reset_list_mutex); static LIST_HEAD(reset_controller_list); +/* Protects reset_gpio_lookup_list */ +static DEFINE_MUTEX(reset_gpio_lookup_mutex); +static LIST_HEAD(reset_gpio_lookup_list); +static DEFINE_IDA(reset_gpio_ida); + /** * struct reset_control - a reset control * @rcdev: a pointer to the reset controller device * this reset control belongs to + * @list: list entry for the rcdev's reset controller list * @id: ID of the reset controller in the reset * controller device + * @refcnt: Number of gets of this reset_control + * @acquired: Only one reset_control may be acquired for a given rcdev and id. + * @shared: Is this a shared (1), or an exclusive (0) reset_control? + * @array: Is this an array of reset controls (1)? + * @deassert_count: Number of times this reset line has been deasserted + * @triggered_count: Number of times this reset line has been reset. Currently + * only used for shared resets, which means that the value + * will be either 0 or 1. */ struct reset_control { struct reset_controller_dev *rcdev; - struct device *dev; + struct list_head list; unsigned int id; + struct kref refcnt; + bool acquired; + bool shared; + bool array; + atomic_t deassert_count; + atomic_t triggered_count; +}; + +/** + * struct reset_control_array - an array of reset controls + * @base: reset control for compatibility with reset control API functions + * @num_rstcs: number of reset controls + * @rstc: array of reset controls + */ +struct reset_control_array { + struct reset_control base; + unsigned int num_rstcs; + struct reset_control *rstc[] __counted_by(num_rstcs); +}; + +/** + * struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices + * @of_args: phandle to the reset controller with all the args like GPIO number + * @swnode: Software node containing the reference to the GPIO provider + * @list: list entry for the reset_gpio_lookup_list + */ +struct reset_gpio_lookup { + struct of_phandle_args of_args; + struct fwnode_handle *swnode; + struct list_head list; }; +static const char *rcdev_name(struct reset_controller_dev *rcdev) +{ + if (rcdev->dev) + return dev_name(rcdev->dev); + + if (rcdev->of_node) + return rcdev->of_node->full_name; + + if (rcdev->of_args) + return rcdev->of_args->np->full_name; + + return NULL; +} + /** * of_reset_simple_xlate - translate reset_spec to the reset line number * @rcdev: a pointer to the reset controller device * @reset_spec: reset line specifier as found in the device tree - * @flags: a flags pointer to fill in (optional) * - * This simple translation function should be used for reset controllers - * with 1:1 mapping, where reset lines can be indexed by number without gaps. + * This static translation function is used by default if of_xlate in + * :c:type:`reset_controller_dev` is not set. It is useful for all reset + * controllers with 1:1 mapping, where reset lines can be indexed by number + * without gaps. */ -int of_reset_simple_xlate(struct reset_controller_dev *rcdev, - const struct of_phandle_args *reset_spec) +static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, + const struct of_phandle_args *reset_spec) { - if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells)) - return -EINVAL; - if (reset_spec->args[0] >= rcdev->nr_resets) return -EINVAL; return reset_spec->args[0]; } -EXPORT_SYMBOL_GPL(of_reset_simple_xlate); /** * reset_controller_register - register a reset controller device @@ -62,14 +123,19 @@ EXPORT_SYMBOL_GPL(of_reset_simple_xlate); */ int reset_controller_register(struct reset_controller_dev *rcdev) { + if (rcdev->of_node && rcdev->of_args) + return -EINVAL; + if (!rcdev->of_xlate) { rcdev->of_reset_n_cells = 1; rcdev->of_xlate = of_reset_simple_xlate; } - mutex_lock(&reset_controller_list_mutex); + INIT_LIST_HEAD(&rcdev->reset_control_head); + + mutex_lock(&reset_list_mutex); list_add(&rcdev->list, &reset_controller_list); - mutex_unlock(&reset_controller_list_mutex); + mutex_unlock(&reset_list_mutex); return 0; } @@ -81,210 +147,1160 @@ EXPORT_SYMBOL_GPL(reset_controller_register); */ void reset_controller_unregister(struct reset_controller_dev *rcdev) { - mutex_lock(&reset_controller_list_mutex); + mutex_lock(&reset_list_mutex); list_del(&rcdev->list); - mutex_unlock(&reset_controller_list_mutex); + mutex_unlock(&reset_list_mutex); } EXPORT_SYMBOL_GPL(reset_controller_unregister); +static void devm_reset_controller_release(struct device *dev, void *res) +{ + reset_controller_unregister(*(struct reset_controller_dev **)res); +} + +/** + * devm_reset_controller_register - resource managed reset_controller_register() + * @dev: device that is registering this reset controller + * @rcdev: a pointer to the initialized reset controller device + * + * Managed reset_controller_register(). For reset controllers registered by + * this function, reset_controller_unregister() is automatically called on + * driver detach. See reset_controller_register() for more information. + */ +int devm_reset_controller_register(struct device *dev, + struct reset_controller_dev *rcdev) +{ + struct reset_controller_dev **rcdevp; + int ret; + + rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp), + GFP_KERNEL); + if (!rcdevp) + return -ENOMEM; + + ret = reset_controller_register(rcdev); + if (ret) { + devres_free(rcdevp); + return ret; + } + + *rcdevp = rcdev; + devres_add(dev, rcdevp); + + return ret; +} +EXPORT_SYMBOL_GPL(devm_reset_controller_register); + +static inline struct reset_control_array * +rstc_to_array(struct reset_control *rstc) { + return container_of(rstc, struct reset_control_array, base); +} + +static int reset_control_array_reset(struct reset_control_array *resets) +{ + int ret, i; + + for (i = 0; i < resets->num_rstcs; i++) { + ret = reset_control_reset(resets->rstc[i]); + if (ret) + return ret; + } + + return 0; +} + +static int reset_control_array_rearm(struct reset_control_array *resets) +{ + struct reset_control *rstc; + int i; + + for (i = 0; i < resets->num_rstcs; i++) { + rstc = resets->rstc[i]; + + if (!rstc) + continue; + + if (WARN_ON(IS_ERR(rstc))) + return -EINVAL; + + if (rstc->shared) { + if (WARN_ON(atomic_read(&rstc->deassert_count) != 0)) + return -EINVAL; + } else { + if (!rstc->acquired) + return -EPERM; + } + } + + for (i = 0; i < resets->num_rstcs; i++) { + rstc = resets->rstc[i]; + + if (rstc && rstc->shared) + WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0); + } + + return 0; +} + +static int reset_control_array_assert(struct reset_control_array *resets) +{ + int ret, i; + + for (i = 0; i < resets->num_rstcs; i++) { + ret = reset_control_assert(resets->rstc[i]); + if (ret) + goto err; + } + + return 0; + +err: + while (i--) + reset_control_deassert(resets->rstc[i]); + return ret; +} + +static int reset_control_array_deassert(struct reset_control_array *resets) +{ + int ret, i; + + for (i = 0; i < resets->num_rstcs; i++) { + ret = reset_control_deassert(resets->rstc[i]); + if (ret) + goto err; + } + + return 0; + +err: + while (i--) + reset_control_assert(resets->rstc[i]); + return ret; +} + +static int reset_control_array_acquire(struct reset_control_array *resets) +{ + unsigned int i; + int err; + + for (i = 0; i < resets->num_rstcs; i++) { + err = reset_control_acquire(resets->rstc[i]); + if (err < 0) + goto release; + } + + return 0; + +release: + while (i--) + reset_control_release(resets->rstc[i]); + + return err; +} + +static void reset_control_array_release(struct reset_control_array *resets) +{ + unsigned int i; + + for (i = 0; i < resets->num_rstcs; i++) + reset_control_release(resets->rstc[i]); +} + +static inline bool reset_control_is_array(struct reset_control *rstc) +{ + return rstc->array; +} + /** * reset_control_reset - reset the controlled device * @rstc: reset controller + * + * On a shared reset line the actual reset pulse is only triggered once for the + * lifetime of the reset_control instance: for all but the first caller this is + * a no-op. + * Consumers must not use reset_control_(de)assert on shared reset lines when + * reset_control_reset has been used. + * + * If rstc is NULL it is an optional reset and the function will just + * return 0. */ int reset_control_reset(struct reset_control *rstc) { - if (rstc->rcdev->ops->reset) - return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); + int ret; + + if (!rstc) + return 0; + + if (WARN_ON(IS_ERR(rstc))) + return -EINVAL; + + if (reset_control_is_array(rstc)) + return reset_control_array_reset(rstc_to_array(rstc)); + + if (!rstc->rcdev->ops->reset) + return -ENOTSUPP; + + if (rstc->shared) { + if (WARN_ON(atomic_read(&rstc->deassert_count) != 0)) + return -EINVAL; + + if (atomic_inc_return(&rstc->triggered_count) != 1) + return 0; + } else { + if (!rstc->acquired) + return -EPERM; + } + + ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); + if (rstc->shared && ret) + atomic_dec(&rstc->triggered_count); - return -ENOSYS; + return ret; } EXPORT_SYMBOL_GPL(reset_control_reset); /** + * reset_control_bulk_reset - reset the controlled devices in order + * @num_rstcs: number of entries in rstcs array + * @rstcs: array of struct reset_control_bulk_data with reset controls set + * + * Issue a reset on all provided reset controls, in order. + * + * See also: reset_control_reset() + */ +int reset_control_bulk_reset(int num_rstcs, + struct reset_control_bulk_data *rstcs) +{ + int ret, i; + + for (i = 0; i < num_rstcs; i++) { + ret = reset_control_reset(rstcs[i].rstc); + if (ret) + return ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(reset_control_bulk_reset); + +/** + * reset_control_rearm - allow shared reset line to be re-triggered" + * @rstc: reset controller + * + * On a shared reset line the actual reset pulse is only triggered once for the + * lifetime of the reset_control instance, except if this call is used. + * + * Calls to this function must be balanced with calls to reset_control_reset, + * a warning is thrown in case triggered_count ever dips below 0. + * + * Consumers must not use reset_control_(de)assert on shared reset lines when + * reset_control_reset or reset_control_rearm have been used. + * + * If rstc is NULL the function will just return 0. + */ +int reset_control_rearm(struct reset_control *rstc) +{ + if (!rstc) + return 0; + + if (WARN_ON(IS_ERR(rstc))) + return -EINVAL; + + if (reset_control_is_array(rstc)) + return reset_control_array_rearm(rstc_to_array(rstc)); + + if (rstc->shared) { + if (WARN_ON(atomic_read(&rstc->deassert_count) != 0)) + return -EINVAL; + + WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0); + } else { + if (!rstc->acquired) + return -EPERM; + } + + return 0; +} +EXPORT_SYMBOL_GPL(reset_control_rearm); + +/** * reset_control_assert - asserts the reset line * @rstc: reset controller + * + * Calling this on an exclusive reset controller guarantees that the reset + * will be asserted. When called on a shared reset controller the line may + * still be deasserted, as long as other users keep it so. + * + * For shared reset controls a driver cannot expect the hw's registers and + * internal state to be reset, but must be prepared for this to happen. + * Consumers must not use reset_control_reset on shared reset lines when + * reset_control_(de)assert has been used. + * + * If rstc is NULL it is an optional reset and the function will just + * return 0. */ int reset_control_assert(struct reset_control *rstc) { - if (rstc->rcdev->ops->assert) - return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); + if (!rstc) + return 0; + + if (WARN_ON(IS_ERR(rstc))) + return -EINVAL; + + if (reset_control_is_array(rstc)) + return reset_control_array_assert(rstc_to_array(rstc)); + + if (rstc->shared) { + if (WARN_ON(atomic_read(&rstc->triggered_count) != 0)) + return -EINVAL; + + if (WARN_ON(atomic_read(&rstc->deassert_count) == 0)) + return -EINVAL; + + if (atomic_dec_return(&rstc->deassert_count) != 0) + return 0; + + /* + * Shared reset controls allow the reset line to be in any state + * after this call, so doing nothing is a valid option. + */ + if (!rstc->rcdev->ops->assert) + return 0; + } else { + /* + * If the reset controller does not implement .assert(), there + * is no way to guarantee that the reset line is asserted after + * this call. + */ + if (!rstc->rcdev->ops->assert) + return -ENOTSUPP; + + if (!rstc->acquired) { + WARN(1, "reset %s (ID: %u) is not acquired\n", + rcdev_name(rstc->rcdev), rstc->id); + return -EPERM; + } + } - return -ENOSYS; + return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); } EXPORT_SYMBOL_GPL(reset_control_assert); /** + * reset_control_bulk_assert - asserts the reset lines in order + * @num_rstcs: number of entries in rstcs array + * @rstcs: array of struct reset_control_bulk_data with reset controls set + * + * Assert the reset lines for all provided reset controls, in order. + * If an assertion fails, already asserted resets are deasserted again. + * + * See also: reset_control_assert() + */ +int reset_control_bulk_assert(int num_rstcs, + struct reset_control_bulk_data *rstcs) +{ + int ret, i; + + for (i = 0; i < num_rstcs; i++) { + ret = reset_control_assert(rstcs[i].rstc); + if (ret) + goto err; + } + + return 0; + +err: + while (i--) + reset_control_deassert(rstcs[i].rstc); + return ret; +} +EXPORT_SYMBOL_GPL(reset_control_bulk_assert); + +/** * reset_control_deassert - deasserts the reset line * @rstc: reset controller + * + * After calling this function, the reset is guaranteed to be deasserted. + * Consumers must not use reset_control_reset on shared reset lines when + * reset_control_(de)assert has been used. + * + * If rstc is NULL it is an optional reset and the function will just + * return 0. */ int reset_control_deassert(struct reset_control *rstc) { - if (rstc->rcdev->ops->deassert) - return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); + if (!rstc) + return 0; - return -ENOSYS; + if (WARN_ON(IS_ERR(rstc))) + return -EINVAL; + + if (reset_control_is_array(rstc)) + return reset_control_array_deassert(rstc_to_array(rstc)); + + if (rstc->shared) { + if (WARN_ON(atomic_read(&rstc->triggered_count) != 0)) + return -EINVAL; + + if (atomic_inc_return(&rstc->deassert_count) != 1) + return 0; + } else { + if (!rstc->acquired) { + WARN(1, "reset %s (ID: %u) is not acquired\n", + rcdev_name(rstc->rcdev), rstc->id); + return -EPERM; + } + } + + /* + * If the reset controller does not implement .deassert(), we assume + * that it handles self-deasserting reset lines via .reset(). In that + * case, the reset lines are deasserted by default. If that is not the + * case, the reset controller driver should implement .deassert() and + * return -ENOTSUPP. + */ + if (!rstc->rcdev->ops->deassert) + return 0; + + return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); } 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 + * reset_control_bulk_deassert - deasserts the reset lines in reverse order + * @num_rstcs: number of entries in rstcs array + * @rstcs: array of struct reset_control_bulk_data with reset controls set + * + * Deassert the reset lines for all provided reset controls, in reverse order. + * If a deassertion fails, already deasserted resets are asserted again. + * + * See also: reset_control_deassert() + */ +int reset_control_bulk_deassert(int num_rstcs, + struct reset_control_bulk_data *rstcs) +{ + int ret, i; + + for (i = num_rstcs - 1; i >= 0; i--) { + ret = reset_control_deassert(rstcs[i].rstc); + if (ret) + goto err; + } + + return 0; + +err: + while (i < num_rstcs) + reset_control_assert(rstcs[i++].rstc); + return ret; +} +EXPORT_SYMBOL_GPL(reset_control_bulk_deassert); + +/** + * reset_control_status - returns a negative errno if not supported, a + * positive value if the reset line is asserted, or zero if the reset + * line is not asserted or if the desc is NULL (optional reset). + * @rstc: reset controller + */ +int reset_control_status(struct reset_control *rstc) +{ + if (!rstc) + return 0; + + if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc)) + return -EINVAL; + + if (rstc->rcdev->ops->status) + return rstc->rcdev->ops->status(rstc->rcdev, rstc->id); + + return -ENOTSUPP; +} +EXPORT_SYMBOL_GPL(reset_control_status); + +/** + * reset_control_acquire() - acquires a reset control for exclusive use + * @rstc: reset control * - * Returns a struct reset_control or IS_ERR() condition containing errno. + * This is used to explicitly acquire a reset control for exclusive use. Note + * that exclusive resets are requested as acquired by default. In order for a + * second consumer to be able to control the reset, the first consumer has to + * release it first. Typically the easiest way to achieve this is to call the + * reset_control_get_exclusive_released() to obtain an instance of the reset + * control. Such reset controls are not acquired by default. * - * Use of id names is optional. + * Consumers implementing shared access to an exclusive reset need to follow + * a specific protocol in order to work together. Before consumers can change + * a reset they must acquire exclusive access using reset_control_acquire(). + * After they are done operating the reset, they must release exclusive access + * with a call to reset_control_release(). Consumers are not granted exclusive + * access to the reset as long as another consumer hasn't released a reset. + * + * See also: reset_control_release() */ -struct reset_control *reset_control_get(struct device *dev, const char *id) +int reset_control_acquire(struct reset_control *rstc) { - struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER); - struct reset_controller_dev *r, *rcdev; + struct reset_control *rc; + + if (!rstc) + return 0; + + if (WARN_ON(IS_ERR(rstc))) + return -EINVAL; + + if (reset_control_is_array(rstc)) + return reset_control_array_acquire(rstc_to_array(rstc)); + + mutex_lock(&reset_list_mutex); + + if (rstc->acquired) { + mutex_unlock(&reset_list_mutex); + return 0; + } + + list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) { + if (rstc != rc && rstc->id == rc->id) { + if (rc->acquired) { + mutex_unlock(&reset_list_mutex); + return -EBUSY; + } + } + } + + rstc->acquired = true; + + mutex_unlock(&reset_list_mutex); + return 0; +} +EXPORT_SYMBOL_GPL(reset_control_acquire); + +/** + * reset_control_bulk_acquire - acquires reset controls for exclusive use + * @num_rstcs: number of entries in rstcs array + * @rstcs: array of struct reset_control_bulk_data with reset controls set + * + * This is used to explicitly acquire reset controls requested with + * reset_control_bulk_get_exclusive_release() for temporary exclusive use. + * + * See also: reset_control_acquire(), reset_control_bulk_release() + */ +int reset_control_bulk_acquire(int num_rstcs, + struct reset_control_bulk_data *rstcs) +{ + int ret, i; + + for (i = 0; i < num_rstcs; i++) { + ret = reset_control_acquire(rstcs[i].rstc); + if (ret) + goto err; + } + + return 0; + +err: + while (i--) + reset_control_release(rstcs[i].rstc); + return ret; +} +EXPORT_SYMBOL_GPL(reset_control_bulk_acquire); + +/** + * reset_control_release() - releases exclusive access to a reset control + * @rstc: reset control + * + * Releases exclusive access right to a reset control previously obtained by a + * call to reset_control_acquire(). Until a consumer calls this function, no + * other consumers will be granted exclusive access. + * + * See also: reset_control_acquire() + */ +void reset_control_release(struct reset_control *rstc) +{ + if (!rstc || WARN_ON(IS_ERR(rstc))) + return; + + if (reset_control_is_array(rstc)) + reset_control_array_release(rstc_to_array(rstc)); + else + rstc->acquired = false; +} +EXPORT_SYMBOL_GPL(reset_control_release); + +/** + * reset_control_bulk_release() - releases exclusive access to reset controls + * @num_rstcs: number of entries in rstcs array + * @rstcs: array of struct reset_control_bulk_data with reset controls set + * + * Releases exclusive access right to reset controls previously obtained by a + * call to reset_control_bulk_acquire(). + * + * See also: reset_control_release(), reset_control_bulk_acquire() + */ +void reset_control_bulk_release(int num_rstcs, + struct reset_control_bulk_data *rstcs) +{ + int i; + + for (i = 0; i < num_rstcs; i++) + reset_control_release(rstcs[i].rstc); +} +EXPORT_SYMBOL_GPL(reset_control_bulk_release); + +static struct reset_control * +__reset_control_get_internal(struct reset_controller_dev *rcdev, + unsigned int index, enum reset_control_flags flags) +{ + bool shared = flags & RESET_CONTROL_FLAGS_BIT_SHARED; + bool acquired = flags & RESET_CONTROL_FLAGS_BIT_ACQUIRED; + struct reset_control *rstc; + + lockdep_assert_held(&reset_list_mutex); + + /* Expect callers to filter out OPTIONAL and DEASSERTED bits */ + if (WARN_ON(flags & ~(RESET_CONTROL_FLAGS_BIT_SHARED | + RESET_CONTROL_FLAGS_BIT_ACQUIRED))) + return ERR_PTR(-EINVAL); + + list_for_each_entry(rstc, &rcdev->reset_control_head, list) { + if (rstc->id == index) { + /* + * Allow creating a secondary exclusive reset_control + * that is initially not acquired for an already + * controlled reset line. + */ + if (!rstc->shared && !shared && !acquired) + break; + + if (WARN_ON(!rstc->shared || !shared)) + return ERR_PTR(-EBUSY); + + kref_get(&rstc->refcnt); + return rstc; + } + } + + rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); + if (!rstc) + return ERR_PTR(-ENOMEM); + + if (!try_module_get(rcdev->owner)) { + kfree(rstc); + return ERR_PTR(-ENODEV); + } + + rstc->rcdev = rcdev; + list_add(&rstc->list, &rcdev->reset_control_head); + rstc->id = index; + kref_init(&rstc->refcnt); + rstc->acquired = acquired; + rstc->shared = shared; + get_device(rcdev->dev); + + return rstc; +} + +static void __reset_control_release(struct kref *kref) +{ + struct reset_control *rstc = container_of(kref, struct reset_control, + refcnt); + + lockdep_assert_held(&reset_list_mutex); + + module_put(rstc->rcdev->owner); + + list_del(&rstc->list); + put_device(rstc->rcdev->dev); + kfree(rstc); +} + +static void __reset_control_put_internal(struct reset_control *rstc) +{ + lockdep_assert_held(&reset_list_mutex); + + if (IS_ERR_OR_NULL(rstc)) + return; + + kref_put(&rstc->refcnt, __reset_control_release); +} + +static void reset_gpio_aux_device_release(struct device *dev) +{ + struct auxiliary_device *adev = to_auxiliary_dev(dev); + + kfree(adev); +} + +static int reset_add_gpio_aux_device(struct device *parent, + struct fwnode_handle *swnode, + int id, void *pdata) +{ + struct auxiliary_device *adev; + int ret; + + adev = kzalloc(sizeof(*adev), GFP_KERNEL); + if (!adev) + return -ENOMEM; + + adev->id = id; + adev->name = "gpio"; + adev->dev.parent = parent; + adev->dev.platform_data = pdata; + adev->dev.release = reset_gpio_aux_device_release; + device_set_node(&adev->dev, swnode); + + ret = auxiliary_device_init(adev); + if (ret) { + kfree(adev); + return ret; + } + + ret = __auxiliary_device_add(adev, "reset"); + if (ret) { + auxiliary_device_uninit(adev); + kfree(adev); + return ret; + } + + return ret; +} + +/* + * @args: phandle to the GPIO provider with all the args like GPIO number + */ +static int __reset_add_reset_gpio_device(const struct of_phandle_args *args) +{ + struct property_entry properties[2] = { }; + unsigned int offset, of_flags, lflags; + struct reset_gpio_lookup *rgpio_dev; + struct device *parent; + int id, ret; + + /* + * Currently only #gpio-cells=2 is supported with the meaning of: + * args[0]: GPIO number + * args[1]: GPIO flags + * TODO: Handle other cases. + */ + if (args->args_count != 2) + return -ENOENT; + + /* + * Registering reset-gpio device might cause immediate + * bind, resulting in its probe() registering new reset controller thus + * taking reset_list_mutex lock via reset_controller_register(). + */ + lockdep_assert_not_held(&reset_list_mutex); + + offset = args->args[0]; + of_flags = args->args[1]; + + /* + * Later we map GPIO flags between OF and Linux, however not all + * constants from include/dt-bindings/gpio/gpio.h and + * include/linux/gpio/machine.h match each other. + * + * FIXME: Find a better way of translating OF flags to GPIO lookup + * flags. + */ + if (of_flags > GPIO_ACTIVE_LOW) { + pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n", + of_flags, offset); + return -EINVAL; + } + + struct gpio_device *gdev __free(gpio_device_put) = + gpio_device_find_by_fwnode(of_fwnode_handle(args->np)); + if (!gdev) + return -EPROBE_DEFER; + + guard(mutex)(&reset_gpio_lookup_mutex); + + list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) { + if (args->np == rgpio_dev->of_args.np) { + if (of_phandle_args_equal(args, &rgpio_dev->of_args)) + return 0; /* Already on the list, done */ + } + } + + lflags = GPIO_PERSISTENT | (of_flags & GPIO_ACTIVE_LOW); + parent = gpio_device_to_device(gdev); + properties[0] = PROPERTY_ENTRY_GPIO("reset-gpios", parent->fwnode, offset, lflags); + + id = ida_alloc(&reset_gpio_ida, GFP_KERNEL); + if (id < 0) + return id; + + /* Not freed on success, because it is persisent subsystem data. */ + rgpio_dev = kzalloc(sizeof(*rgpio_dev), GFP_KERNEL); + if (!rgpio_dev) { + ret = -ENOMEM; + goto err_ida_free; + } + + rgpio_dev->of_args = *args; + /* + * We keep the device_node reference, but of_args.np is put at the end + * of __of_reset_control_get(), so get it one more time. + * Hold reference as long as rgpio_dev memory is valid. + */ + of_node_get(rgpio_dev->of_args.np); + + rgpio_dev->swnode = fwnode_create_software_node(properties, NULL); + if (IS_ERR(rgpio_dev->swnode)) { + ret = PTR_ERR(rgpio_dev->swnode); + goto err_put_of_node; + } + + ret = reset_add_gpio_aux_device(parent, rgpio_dev->swnode, id, + &rgpio_dev->of_args); + if (ret) + goto err_del_swnode; + + list_add(&rgpio_dev->list, &reset_gpio_lookup_list); + + return 0; + +err_del_swnode: + fwnode_remove_software_node(rgpio_dev->swnode); +err_put_of_node: + of_node_put(rgpio_dev->of_args.np); + kfree(rgpio_dev); +err_ida_free: + ida_free(&reset_gpio_ida, id); + + return ret; +} + +static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args, + bool gpio_fallback) +{ + struct reset_controller_dev *rcdev; + + lockdep_assert_held(&reset_list_mutex); + + list_for_each_entry(rcdev, &reset_controller_list, list) { + if (gpio_fallback) { + if (rcdev->of_args && of_phandle_args_equal(args, + rcdev->of_args)) + return rcdev; + } else { + if (args->np == rcdev->of_node) + return rcdev; + } + } + + return NULL; +} + +struct reset_control * +__of_reset_control_get(struct device_node *node, const char *id, int index, + enum reset_control_flags flags) +{ + bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL; + bool gpio_fallback = false; + struct reset_control *rstc; + struct reset_controller_dev *rcdev; struct of_phandle_args args; - int index = 0; int rstc_id; int ret; - if (!dev) + if (!node) return ERR_PTR(-EINVAL); - if (id) - index = of_property_match_string(dev->of_node, + if (id) { + index = of_property_match_string(node, "reset-names", id); - ret = of_parse_phandle_with_args(dev->of_node, "resets", "#reset-cells", + if (index == -EILSEQ) + return ERR_PTR(index); + if (index < 0) + return optional ? NULL : ERR_PTR(-ENOENT); + } + + ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", index, &args); - if (ret) + if (ret == -EINVAL) return ERR_PTR(ret); + if (ret) { + if (!IS_ENABLED(CONFIG_RESET_GPIO)) + return optional ? NULL : ERR_PTR(ret); - mutex_lock(&reset_controller_list_mutex); - rcdev = NULL; - list_for_each_entry(r, &reset_controller_list, list) { - if (args.np == r->of_node) { - rcdev = r; - break; + /* + * There can be only one reset-gpio for regular devices, so + * don't bother with the "reset-gpios" phandle index. + */ + ret = of_parse_phandle_with_args(node, "reset-gpios", "#gpio-cells", + 0, &args); + if (ret) + return optional ? NULL : ERR_PTR(ret); + + gpio_fallback = true; + + ret = __reset_add_reset_gpio_device(&args); + if (ret) { + rstc = ERR_PTR(ret); + goto out_put; } } - of_node_put(args.np); + mutex_lock(&reset_list_mutex); + rcdev = __reset_find_rcdev(&args, gpio_fallback); if (!rcdev) { - mutex_unlock(&reset_controller_list_mutex); - return ERR_PTR(-ENODEV); + rstc = ERR_PTR(-EPROBE_DEFER); + goto out_unlock; + } + + if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) { + rstc = ERR_PTR(-EINVAL); + goto out_unlock; } rstc_id = rcdev->of_xlate(rcdev, &args); if (rstc_id < 0) { - mutex_unlock(&reset_controller_list_mutex); - return ERR_PTR(rstc_id); + rstc = ERR_PTR(rstc_id); + goto out_unlock; } - try_module_get(rcdev->owner); - mutex_unlock(&reset_controller_list_mutex); + flags &= ~RESET_CONTROL_FLAGS_BIT_OPTIONAL; - rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); - if (!rstc) { - module_put(rcdev->owner); - return ERR_PTR(-ENOMEM); - } + /* reset_list_mutex also protects the rcdev's reset_control list */ + rstc = __reset_control_get_internal(rcdev, rstc_id, flags); - rstc->dev = dev; - rstc->rcdev = rcdev; - rstc->id = rstc_id; +out_unlock: + mutex_unlock(&reset_list_mutex); +out_put: + of_node_put(args.np); return rstc; } -EXPORT_SYMBOL_GPL(reset_control_get); +EXPORT_SYMBOL_GPL(__of_reset_control_get); + +struct reset_control *__reset_control_get(struct device *dev, const char *id, + int index, enum reset_control_flags flags) +{ + bool shared = flags & RESET_CONTROL_FLAGS_BIT_SHARED; + bool acquired = flags & RESET_CONTROL_FLAGS_BIT_ACQUIRED; + bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL; + + if (WARN_ON(shared && acquired)) + return ERR_PTR(-EINVAL); + + if (dev->of_node) + return __of_reset_control_get(dev->of_node, id, index, flags); + + return optional ? NULL : ERR_PTR(-ENOENT); +} +EXPORT_SYMBOL_GPL(__reset_control_get); + +int __reset_control_bulk_get(struct device *dev, int num_rstcs, + struct reset_control_bulk_data *rstcs, + enum reset_control_flags flags) +{ + int ret, i; + + for (i = 0; i < num_rstcs; i++) { + rstcs[i].rstc = __reset_control_get(dev, rstcs[i].id, 0, flags); + if (IS_ERR(rstcs[i].rstc)) { + ret = PTR_ERR(rstcs[i].rstc); + goto err; + } + } + + return 0; + +err: + mutex_lock(&reset_list_mutex); + while (i--) + __reset_control_put_internal(rstcs[i].rstc); + mutex_unlock(&reset_list_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(__reset_control_bulk_get); + +static void reset_control_array_put(struct reset_control_array *resets) +{ + int i; + + mutex_lock(&reset_list_mutex); + for (i = 0; i < resets->num_rstcs; i++) + __reset_control_put_internal(resets->rstc[i]); + mutex_unlock(&reset_list_mutex); + kfree(resets); +} /** * reset_control_put - free the reset controller * @rstc: reset controller */ - void reset_control_put(struct reset_control *rstc) { - if (IS_ERR(rstc)) + if (IS_ERR_OR_NULL(rstc)) return; - module_put(rstc->rcdev->owner); - kfree(rstc); + if (reset_control_is_array(rstc)) { + reset_control_array_put(rstc_to_array(rstc)); + return; + } + + mutex_lock(&reset_list_mutex); + __reset_control_put_internal(rstc); + mutex_unlock(&reset_list_mutex); } EXPORT_SYMBOL_GPL(reset_control_put); +/** + * reset_control_bulk_put - free the reset controllers + * @num_rstcs: number of entries in rstcs array + * @rstcs: array of struct reset_control_bulk_data with reset controls set + */ +void reset_control_bulk_put(int num_rstcs, struct reset_control_bulk_data *rstcs) +{ + mutex_lock(&reset_list_mutex); + while (num_rstcs--) + __reset_control_put_internal(rstcs[num_rstcs].rstc); + mutex_unlock(&reset_list_mutex); +} +EXPORT_SYMBOL_GPL(reset_control_bulk_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) +static void devm_reset_control_release_deasserted(struct device *dev, void *res) +{ + struct reset_control *rstc = *(struct reset_control **)res; + + reset_control_assert(rstc); + reset_control_put(rstc); +} + +struct reset_control * +__devm_reset_control_get(struct device *dev, const char *id, int index, + enum reset_control_flags flags) { struct reset_control **ptr, *rstc; + bool deasserted = flags & RESET_CONTROL_FLAGS_BIT_DEASSERTED; - ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), + ptr = devres_alloc(deasserted ? devm_reset_control_release_deasserted : + 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 { + flags &= ~RESET_CONTROL_FLAGS_BIT_DEASSERTED; + + rstc = __reset_control_get(dev, id, index, flags); + if (IS_ERR_OR_NULL(rstc)) { devres_free(ptr); + return rstc; + } + + if (deasserted) { + int ret; + + ret = reset_control_deassert(rstc); + if (ret) { + reset_control_put(rstc); + devres_free(ptr); + return ERR_PTR(ret); + } } + *ptr = rstc; + devres_add(dev, ptr); + return rstc; } -EXPORT_SYMBOL_GPL(devm_reset_control_get); +EXPORT_SYMBOL_GPL(__devm_reset_control_get); + +struct reset_control_bulk_devres { + int num_rstcs; + struct reset_control_bulk_data *rstcs; +}; -static int devm_reset_control_match(struct device *dev, void *res, void *data) +static void devm_reset_control_bulk_release(struct device *dev, void *res) { - struct reset_control **rstc = res; - if (WARN_ON(!rstc || !*rstc)) - return 0; - return *rstc == data; + struct reset_control_bulk_devres *devres = res; + + reset_control_bulk_put(devres->num_rstcs, devres->rstcs); } -/** - * devm_reset_control_put - resource managed reset_control_put() - * @rstc: reset controller to free - * - * Deallocate a reset control allocated withd devm_reset_control_get(). - * This function will not need to be called normally, as devres will take - * care of freeing the resource. - */ -void devm_reset_control_put(struct reset_control *rstc) +static void devm_reset_control_bulk_release_deasserted(struct device *dev, void *res) { + struct reset_control_bulk_devres *devres = res; + + reset_control_bulk_assert(devres->num_rstcs, devres->rstcs); + reset_control_bulk_put(devres->num_rstcs, devres->rstcs); +} + +int __devm_reset_control_bulk_get(struct device *dev, int num_rstcs, + struct reset_control_bulk_data *rstcs, + enum reset_control_flags flags) +{ + struct reset_control_bulk_devres *ptr; + bool deasserted = flags & RESET_CONTROL_FLAGS_BIT_DEASSERTED; int ret; - ret = devres_release(rstc->dev, devm_reset_control_release, - devm_reset_control_match, rstc); - if (ret) - WARN_ON(ret); + ptr = devres_alloc(deasserted ? devm_reset_control_bulk_release_deasserted : + devm_reset_control_bulk_release, sizeof(*ptr), + GFP_KERNEL); + if (!ptr) + return -ENOMEM; + + flags &= ~RESET_CONTROL_FLAGS_BIT_DEASSERTED; + + ret = __reset_control_bulk_get(dev, num_rstcs, rstcs, flags); + if (ret < 0) { + devres_free(ptr); + return ret; + } + + if (deasserted) { + ret = reset_control_bulk_deassert(num_rstcs, rstcs); + if (ret) { + reset_control_bulk_put(num_rstcs, rstcs); + devres_free(ptr); + return ret; + } + } + + ptr->num_rstcs = num_rstcs; + ptr->rstcs = rstcs; + devres_add(dev, ptr); + + return 0; } -EXPORT_SYMBOL_GPL(devm_reset_control_put); +EXPORT_SYMBOL_GPL(__devm_reset_control_bulk_get); /** - * device_reset - find reset controller associated with the device - * and perform reset + * __device_reset - find reset controller associated with the device + * and perform reset * @dev: device to be reset by the controller + * @optional: whether it is optional to reset the device * - * Convenience wrapper for reset_control_get() and reset_control_reset(). + * Convenience wrapper for __reset_control_get() and reset_control_reset(). * This is useful for the common case of devices with single, dedicated reset - * lines. + * lines. _RST firmware method will be called for devices with ACPI. */ -int device_reset(struct device *dev) +int __device_reset(struct device *dev, bool optional) { + enum reset_control_flags flags; struct reset_control *rstc; int ret; - rstc = reset_control_get(dev, NULL); +#ifdef CONFIG_ACPI + acpi_handle handle = ACPI_HANDLE(dev); + + if (handle) { + if (!acpi_has_method(handle, "_RST")) + return optional ? 0 : -ENOENT; + if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, + NULL))) + return -EIO; + } +#endif + + flags = optional ? RESET_CONTROL_OPTIONAL_EXCLUSIVE : RESET_CONTROL_EXCLUSIVE; + rstc = __reset_control_get(dev, NULL, 0, flags); if (IS_ERR(rstc)) return PTR_ERR(rstc); @@ -294,4 +1310,130 @@ int device_reset(struct device *dev) return ret; } -EXPORT_SYMBOL_GPL(device_reset); +EXPORT_SYMBOL_GPL(__device_reset); + +/* + * APIs to manage an array of reset controls. + */ + +/** + * of_reset_control_get_count - Count number of resets available with a device + * + * @node: device node that contains 'resets'. + * + * Returns positive reset count on success, or error number on failure and + * on count being zero. + */ +static int of_reset_control_get_count(struct device_node *node) +{ + int count; + + if (!node) + return -EINVAL; + + count = of_count_phandle_with_args(node, "resets", "#reset-cells"); + if (count == 0) + count = -ENOENT; + + return count; +} + +/** + * of_reset_control_array_get - Get a list of reset controls using + * device node. + * + * @np: device node for the device that requests the reset controls array + * @flags: whether reset controls are shared, optional, acquired + * + * Returns pointer to allocated reset_control on success or error on failure + */ +struct reset_control * +of_reset_control_array_get(struct device_node *np, enum reset_control_flags flags) +{ + bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL; + struct reset_control_array *resets; + struct reset_control *rstc; + int num, i; + + num = of_reset_control_get_count(np); + if (num < 0) + return optional ? NULL : ERR_PTR(num); + + resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL); + if (!resets) + return ERR_PTR(-ENOMEM); + resets->num_rstcs = num; + + for (i = 0; i < num; i++) { + rstc = __of_reset_control_get(np, NULL, i, flags); + if (IS_ERR(rstc)) + goto err_rst; + resets->rstc[i] = rstc; + } + resets->base.array = true; + + return &resets->base; + +err_rst: + mutex_lock(&reset_list_mutex); + while (--i >= 0) + __reset_control_put_internal(resets->rstc[i]); + mutex_unlock(&reset_list_mutex); + + kfree(resets); + + return rstc; +} +EXPORT_SYMBOL_GPL(of_reset_control_array_get); + +/** + * devm_reset_control_array_get - Resource managed reset control array get + * + * @dev: device that requests the list of reset controls + * @flags: whether reset controls are shared, optional, acquired + * + * The reset control array APIs are intended for a list of resets + * that just have to be asserted or deasserted, without any + * requirements on the order. + * + * Returns pointer to allocated reset_control on success or error on failure + */ +struct reset_control * +devm_reset_control_array_get(struct device *dev, enum reset_control_flags flags) +{ + struct reset_control **ptr, *rstc; + + ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), + GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + rstc = of_reset_control_array_get(dev->of_node, flags); + if (IS_ERR_OR_NULL(rstc)) { + devres_free(ptr); + return rstc; + } + + *ptr = rstc; + devres_add(dev, ptr); + + return rstc; +} +EXPORT_SYMBOL_GPL(devm_reset_control_array_get); + +/** + * reset_control_get_count - Count number of resets available with a device + * + * @dev: device for which to return the number of resets + * + * Returns positive reset count on success, or error number on failure and + * on count being zero. + */ +int reset_control_get_count(struct device *dev) +{ + if (dev->of_node) + return of_reset_control_get_count(dev->of_node); + + return -ENOENT; +} +EXPORT_SYMBOL_GPL(reset_control_get_count); |