diff options
Diffstat (limited to 'drivers/reset/core.c')
| -rw-r--r-- | drivers/reset/core.c | 1289 |
1 files changed, 1289 insertions, 0 deletions
diff --git a/drivers/reset/core.c b/drivers/reset/core.c new file mode 100644 index 000000000..92cc13ef3 --- /dev/null +++ b/drivers/reset/core.c @@ -0,0 +1,1289 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Reset Controller framework + * + * Copyright 2013 Philipp Zabel, Pengutronix + */ +#include <linux/atomic.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/kref.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/acpi.h> +#include <linux/reset.h> +#include <linux/reset-controller.h> +#include <linux/slab.h> + +static DEFINE_MUTEX(reset_list_mutex); +static LIST_HEAD(reset_controller_list); + +static DEFINE_MUTEX(reset_lookup_mutex); +static LIST_HEAD(reset_lookup_list); + +/** + * 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 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[]; +}; + +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; + + 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 + * + * 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. + */ +static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, + const struct of_phandle_args *reset_spec) +{ + if (reset_spec->args[0] >= rcdev->nr_resets) + return -EINVAL; + + return reset_spec->args[0]; +} + +/** + * reset_controller_register - register a reset controller device + * @rcdev: a pointer to the initialized reset controller device + */ +int reset_controller_register(struct reset_controller_dev *rcdev) +{ + if (!rcdev->of_xlate) { + rcdev->of_reset_n_cells = 1; + rcdev->of_xlate = of_reset_simple_xlate; + } + + INIT_LIST_HEAD(&rcdev->reset_control_head); + + mutex_lock(&reset_list_mutex); + list_add(&rcdev->list, &reset_controller_list); + mutex_unlock(&reset_list_mutex); + + return 0; +} +EXPORT_SYMBOL_GPL(reset_controller_register); + +/** + * reset_controller_unregister - unregister a reset controller device + * @rcdev: a pointer to the reset controller device + */ +void reset_controller_unregister(struct reset_controller_dev *rcdev) +{ + mutex_lock(&reset_list_mutex); + list_del(&rcdev->list); + 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); + +/** + * reset_controller_add_lookup - register a set of lookup entries + * @lookup: array of reset lookup entries + * @num_entries: number of entries in the lookup array + */ +void reset_controller_add_lookup(struct reset_control_lookup *lookup, + unsigned int num_entries) +{ + struct reset_control_lookup *entry; + unsigned int i; + + mutex_lock(&reset_lookup_mutex); + for (i = 0; i < num_entries; i++) { + entry = &lookup[i]; + + if (!entry->dev_id || !entry->provider) { + pr_warn("%s(): reset lookup entry badly specified, skipping\n", + __func__); + continue; + } + + list_add_tail(&entry->list, &reset_lookup_list); + } + mutex_unlock(&reset_lookup_mutex); +} +EXPORT_SYMBOL_GPL(reset_controller_add_lookup); + +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) +{ + 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 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) + 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 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) + return 0; + + 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_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 + * + * 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. + * + * 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() + */ +int reset_control_acquire(struct reset_control *rstc) +{ + 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, bool shared, bool acquired) +{ + struct reset_control *rstc; + + lockdep_assert_held(&reset_list_mutex); + + 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; + + 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); + 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); +} + +struct reset_control * +__of_reset_control_get(struct device_node *node, const char *id, int index, + bool shared, bool optional, bool acquired) +{ + struct reset_control *rstc; + struct reset_controller_dev *r, *rcdev; + struct of_phandle_args args; + int rstc_id; + int ret; + + if (!node) + return ERR_PTR(-EINVAL); + + if (id) { + index = of_property_match_string(node, + "reset-names", id); + 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 == -EINVAL) + return ERR_PTR(ret); + if (ret) + return optional ? NULL : ERR_PTR(ret); + + mutex_lock(&reset_list_mutex); + rcdev = NULL; + list_for_each_entry(r, &reset_controller_list, list) { + if (args.np == r->of_node) { + rcdev = r; + break; + } + } + + if (!rcdev) { + rstc = ERR_PTR(-EPROBE_DEFER); + goto out; + } + + if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) { + rstc = ERR_PTR(-EINVAL); + goto out; + } + + rstc_id = rcdev->of_xlate(rcdev, &args); + if (rstc_id < 0) { + rstc = ERR_PTR(rstc_id); + goto out; + } + + /* reset_list_mutex also protects the rcdev's reset_control list */ + rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired); + +out: + mutex_unlock(&reset_list_mutex); + of_node_put(args.np); + + return rstc; +} +EXPORT_SYMBOL_GPL(__of_reset_control_get); + +static struct reset_controller_dev * +__reset_controller_by_name(const char *name) +{ + struct reset_controller_dev *rcdev; + + lockdep_assert_held(&reset_list_mutex); + + list_for_each_entry(rcdev, &reset_controller_list, list) { + if (!rcdev->dev) + continue; + + if (!strcmp(name, dev_name(rcdev->dev))) + return rcdev; + } + + return NULL; +} + +static struct reset_control * +__reset_control_get_from_lookup(struct device *dev, const char *con_id, + bool shared, bool optional, bool acquired) +{ + const struct reset_control_lookup *lookup; + struct reset_controller_dev *rcdev; + const char *dev_id = dev_name(dev); + struct reset_control *rstc = NULL; + + mutex_lock(&reset_lookup_mutex); + + list_for_each_entry(lookup, &reset_lookup_list, list) { + if (strcmp(lookup->dev_id, dev_id)) + continue; + + if ((!con_id && !lookup->con_id) || + ((con_id && lookup->con_id) && + !strcmp(con_id, lookup->con_id))) { + mutex_lock(&reset_list_mutex); + rcdev = __reset_controller_by_name(lookup->provider); + if (!rcdev) { + mutex_unlock(&reset_list_mutex); + mutex_unlock(&reset_lookup_mutex); + /* Reset provider may not be ready yet. */ + return ERR_PTR(-EPROBE_DEFER); + } + + rstc = __reset_control_get_internal(rcdev, + lookup->index, + shared, acquired); + mutex_unlock(&reset_list_mutex); + break; + } + } + + mutex_unlock(&reset_lookup_mutex); + + if (!rstc) + return optional ? NULL : ERR_PTR(-ENOENT); + + return rstc; +} + +struct reset_control *__reset_control_get(struct device *dev, const char *id, + int index, bool shared, bool optional, + bool acquired) +{ + if (WARN_ON(shared && acquired)) + return ERR_PTR(-EINVAL); + + if (dev->of_node) + return __of_reset_control_get(dev->of_node, id, index, shared, + optional, acquired); + + return __reset_control_get_from_lookup(dev, id, shared, optional, + acquired); +} +EXPORT_SYMBOL_GPL(__reset_control_get); + +int __reset_control_bulk_get(struct device *dev, int num_rstcs, + struct reset_control_bulk_data *rstcs, + bool shared, bool optional, bool acquired) +{ + int ret, i; + + for (i = 0; i < num_rstcs; i++) { + rstcs[i].rstc = __reset_control_get(dev, rstcs[i].id, 0, + shared, optional, acquired); + 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_OR_NULL(rstc)) + return; + + 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); +} + +struct reset_control * +__devm_reset_control_get(struct device *dev, const char *id, int index, + bool shared, bool optional, bool acquired) +{ + 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, index, shared, optional, acquired); + 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_get); + +struct reset_control_bulk_devres { + int num_rstcs; + struct reset_control_bulk_data *rstcs; +}; + +static void devm_reset_control_bulk_release(struct device *dev, void *res) +{ + struct reset_control_bulk_devres *devres = res; + + 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, + bool shared, bool optional, bool acquired) +{ + struct reset_control_bulk_devres *ptr; + int ret; + + ptr = devres_alloc(devm_reset_control_bulk_release, sizeof(*ptr), + GFP_KERNEL); + if (!ptr) + return -ENOMEM; + + ret = __reset_control_bulk_get(dev, num_rstcs, rstcs, shared, optional, acquired); + if (ret < 0) { + 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_bulk_get); + +/** + * __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(). + * This is useful for the common case of devices with single, dedicated reset + * lines. _RST firmware method will be called for devices with ACPI. + */ +int __device_reset(struct device *dev, bool optional) +{ + struct reset_control *rstc; + int ret; + +#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 + + rstc = __reset_control_get(dev, NULL, 0, 0, optional, true); + if (IS_ERR(rstc)) + return PTR_ERR(rstc); + + ret = reset_control_reset(rstc); + + reset_control_put(rstc); + + return ret; +} +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 + * @shared: whether reset controls are shared or not + * @optional: whether it is optional to get the reset controls + * @acquired: only one reset control may be acquired for a given controller + * and ID + * + * Returns pointer to allocated reset_control on success or error on failure + */ +struct reset_control * +of_reset_control_array_get(struct device_node *np, bool shared, bool optional, + bool acquired) +{ + 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); + + for (i = 0; i < num; i++) { + rstc = __of_reset_control_get(np, NULL, i, shared, optional, + acquired); + if (IS_ERR(rstc)) + goto err_rst; + resets->rstc[i] = rstc; + } + resets->num_rstcs = num; + 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 + * @shared: whether reset controls are shared or not + * @optional: whether it is optional to get the reset controls + * + * 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, bool shared, bool optional) +{ + 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, shared, optional, true); + 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); + +static int reset_control_get_count_from_lookup(struct device *dev) +{ + const struct reset_control_lookup *lookup; + const char *dev_id; + int count = 0; + + if (!dev) + return -EINVAL; + + dev_id = dev_name(dev); + mutex_lock(&reset_lookup_mutex); + + list_for_each_entry(lookup, &reset_lookup_list, list) { + if (!strcmp(lookup->dev_id, dev_id)) + count++; + } + + mutex_unlock(&reset_lookup_mutex); + + if (count == 0) + count = -ENOENT; + + return count; +} + +/** + * 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 reset_control_get_count_from_lookup(dev); +} +EXPORT_SYMBOL_GPL(reset_control_get_count); |