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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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SPDX-License-Identifier: GPL-2.0-or-later/* * Reset Controller framework * * Copyright 2013 Philipp Zabel, Pengutronix */
#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/fwnode.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/property.h>#include <linux/reset.h>#include <linux/reset-controller.h>#include <linux/slab.h>#include <linux/srcu.h>
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 * @srcu: protects the rcdev pointer from removal during consumer access * @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. * @lock: serializes the internals of reset_control_acquire() */struct reset_control { struct reset_controller_dev __rcu *rcdev; struct srcu_struct srcu; 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 mutex lock;};
/** * 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 * @ref_args: Reference 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 * @adev: Auxiliary device representing the reset controller */struct reset_gpio_lookup { struct fwnode_reference_args ref_args; struct fwnode_handle *swnode; struct list_head list; struct auxiliary_device adev;};
static const char *rcdev_name(struct reset_controller_dev *rcdev){ if (rcdev->dev) return dev_name(rcdev->dev);
if (rcdev->fwnode) return fwnode_get_name(rcdev->fwnode);
return NULL;}
/** * fwnode_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 firmware * * This static translation function is used by default if neither fwnode_xlate * not 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 fwnode_reset_simple_xlate(struct reset_controller_dev *rcdev, const struct fwnode_reference_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_node && rcdev->fwnode) || (rcdev->of_xlate && rcdev->fwnode_xlate)) return -EINVAL;
if (rcdev->of_node && !rcdev->fwnode) rcdev->fwnode = of_fwnode_handle(rcdev->of_node);
if (!rcdev->fwnode) { rcdev->fwnode = dev_fwnode(rcdev->dev); if (!rcdev->fwnode) return -EINVAL; }
if (rcdev->of_xlate) rcdev->fwnode_reset_n_cells = rcdev->of_reset_n_cells;
if (!rcdev->fwnode_xlate && !rcdev->of_xlate) { rcdev->fwnode_xlate = fwnode_reset_simple_xlate; rcdev->fwnode_reset_n_cells = 1; }
INIT_LIST_HEAD(&rcdev->reset_control_head); mutex_init(&rcdev->lock);
guard(mutex)(&reset_list_mutex);
list_add(&rcdev->list, &reset_controller_list);
return 0;}EXPORT_SYMBOL_GPL(reset_controller_register);
static void reset_controller_remove(struct reset_controller_dev *rcdev, struct reset_control *rstc){ lockdep_assert_held(&rcdev->lock);
list_del(&rstc->list); module_put(rcdev->owner); put_device(rcdev->dev);}
/** * 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){ struct reset_control *rstc, *pos;
scoped_guard(mutex, &reset_list_mutex) list_del(&rcdev->list);
scoped_guard(mutex, &rcdev->lock) { /* * Numb but don't free the remaining reset control handles that are * still held by consumers. */ list_for_each_entry_safe(rstc, pos, &rcdev->reset_control_head, list) { rcu_assign_pointer(rstc->rcdev, NULL); synchronize_srcu(&rstc->srcu); reset_controller_remove(rcdev, rstc); } }
mutex_destroy(&rcdev->lock);}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){ struct reset_controller_dev *rcdev; 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));
guard(srcu)(&rstc->srcu);
rcdev = srcu_dereference(rstc->rcdev, &rstc->srcu); if (!rcdev) return -ENODEV;
if (!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 = rcdev->ops->reset(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){ struct reset_controller_dev *rcdev;
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));
guard(srcu)(&rstc->srcu);
rcdev = srcu_dereference(rstc->rcdev, &rstc->srcu); if (!rcdev) return -ENODEV;
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 (!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 (!rcdev->ops->assert) return -ENOTSUPP;
if (!rstc->acquired) { WARN(1, "reset %s (ID: %u) is not acquired\n", rcdev_name(rcdev), rstc->id); return -EPERM; } }
return rcdev->ops->assert(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){ struct reset_controller_dev *rcdev;
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));
guard(srcu)(&rstc->srcu);
rcdev = srcu_dereference(rstc->rcdev, &rstc->srcu); if (!rcdev) return -ENODEV;
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(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 (!rcdev->ops->deassert) return 0;
return rcdev->ops->deassert(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){ struct reset_controller_dev *rcdev;
if (!rstc) return 0;
if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc)) return -EINVAL;
guard(srcu)(&rstc->srcu);
rcdev = srcu_dereference(rstc->rcdev, &rstc->srcu); if (!rcdev) return -ENODEV;
if (rcdev->ops->status) return rcdev->ops->status(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_controller_dev *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));
guard(mutex)(&rstc->lock);
if (rstc->acquired) return 0;
guard(srcu)(&rstc->srcu);
rcdev = srcu_dereference(rstc->rcdev, &rstc->srcu); if (!rcdev) return -ENODEV;
scoped_guard(mutex, &rcdev->lock) { list_for_each_entry(rc, &rcdev->reset_control_head, list) { if (rstc != rc && rstc->id == rc->id) { if (rc->acquired) return -EBUSY; } } }
rstc->acquired = true;
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; int ret;
lockdep_assert_held(&rcdev->lock);
/* 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_obj(*rstc); if (!rstc) return ERR_PTR(-ENOMEM);
ret = init_srcu_struct(&rstc->srcu); if (ret) { kfree(rstc); return ERR_PTR(ret); }
if (!try_module_get(rcdev->owner)) { cleanup_srcu_struct(&rstc->srcu); kfree(rstc); return ERR_PTR(-ENODEV); }
rcu_assign_pointer(rstc->rcdev, rcdev); list_add(&rstc->list, &rcdev->reset_control_head); rstc->id = index; kref_init(&rstc->refcnt); mutex_init(&rstc->lock); 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); struct reset_controller_dev *rcdev;
lockdep_assert_held(&rstc->srcu);
rcdev = rcu_replace_pointer(rstc->rcdev, NULL, true); if (rcdev) { lockdep_assert_held(&rcdev->lock); reset_controller_remove(rcdev, rstc); }
mutex_destroy(&rstc->lock);}
static void reset_control_put_internal(struct reset_control *rstc){ struct reset_controller_dev *rcdev; int ret = 0;
if (IS_ERR_OR_NULL(rstc)) return;
scoped_guard(srcu, &rstc->srcu) { rcdev = srcu_dereference(rstc->rcdev, &rstc->srcu); if (!rcdev) /* Already released. */ return;
guard(mutex)(&rcdev->lock); ret = kref_put(&rstc->refcnt, __reset_control_release); }
if (ret) { synchronize_srcu(&rstc->srcu); cleanup_srcu_struct(&rstc->srcu); kfree(rstc); }}
static void reset_gpio_aux_device_release(struct device *dev){ WARN(1, "reset-gpio device %s should never have been removed", dev_name(dev));}
static int reset_create_gpio_aux_device(struct reset_gpio_lookup *rgpio_dev, struct device *parent){ struct auxiliary_device *adev = &rgpio_dev->adev; int ret, id;
id = ida_alloc(&reset_gpio_ida, GFP_KERNEL); if (id < 0) return -ENOMEM;
adev->id = id; adev->name = "gpio"; adev->dev.parent = parent; adev->dev.platform_data = &rgpio_dev->ref_args; adev->dev.release = reset_gpio_aux_device_release; device_set_node(&adev->dev, rgpio_dev->swnode);
ret = auxiliary_device_init(adev); if (ret) { ida_free(&reset_gpio_ida, id); return ret; }
ret = __auxiliary_device_add(adev, "reset"); if (ret) { auxiliary_device_uninit(adev); ida_free(&reset_gpio_ida, id); return ret; }
return 0;}
static void reset_gpio_add_devlink(struct fwnode_handle *fwnode, struct reset_gpio_lookup *rgpio_dev){ struct device *consumer;
/* * We must use get_dev_from_fwnode() and not ref_find_device_by_node() * because the latter only considers the platform bus while we want to * get consumers of any kind that can be associated with firmware * nodes: auxiliary, soundwire, etc. */ consumer = get_dev_from_fwnode(fwnode); if (consumer) { if (!device_link_add(consumer, &rgpio_dev->adev.dev, DL_FLAG_AUTOREMOVE_CONSUMER)) pr_warn("Failed to create a device link between reset-gpio and its consumer");
put_device(consumer); } /* * else { } * * TODO: If ever there's a case where we need to support shared * reset-gpios retrieved from a device node for which there's no * device present yet, this is where we'd set up a notifier waiting * for the device to appear in the system. This would be a lot of code * that would go unused for now so let's cross that bridge when and if * we get there. */}
/* TODO: move it out into drivers/base/ */static bool fwnode_reference_args_equal(const struct fwnode_reference_args *left, const struct fwnode_reference_args *right){ return left->fwnode == right->fwnode && left->nargs == right->nargs && !memcmp(left->args, right->args, sizeof(left->args[0]) * left->nargs);}
/* * @np: OF-node associated with the consumer * @args: Reference to the GPIO provider with all the args like GPIO number */static int __reset_add_reset_gpio_device(struct fwnode_handle *fwnode, const struct fwnode_reference_args *args){ struct property_entry properties[3] = { }; unsigned int offset, flags, lflags; struct reset_gpio_lookup *rgpio_dev; struct device *parent; int ret, prop = 0;
/* * 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->nargs != 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]; 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 (flags > GPIO_ACTIVE_LOW) { pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n", flags, offset); return -EINVAL; }
struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(args->fwnode); if (!gdev) return -EPROBE_DEFER;
guard(mutex)(&reset_gpio_lookup_mutex);
list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) { if (fwnode_reference_args_equal(args, &rgpio_dev->ref_args)) { /* * Already on the list, create the device link * and stop here. */ reset_gpio_add_devlink(fwnode, rgpio_dev); return 0; } }
lflags = GPIO_PERSISTENT | (flags & GPIO_ACTIVE_LOW); parent = gpio_device_to_device(gdev); properties[prop++] = PROPERTY_ENTRY_STRING("compatible", "reset-gpio"); properties[prop++] = PROPERTY_ENTRY_GPIO("reset-gpios", parent->fwnode, offset, lflags);
/* Not freed on success, because it is persisent subsystem data. */ rgpio_dev = kzalloc_obj(*rgpio_dev); if (!rgpio_dev) return -ENOMEM;
rgpio_dev->ref_args = *args; /* * We keep the fwnode_handle reference, but ref_args.fwnode is put at * the end of __fwnode_reset_control_get(), so get it one more time. * Hold reference as long as rgpio_dev memory is valid. */ fwnode_handle_get(rgpio_dev->ref_args.fwnode);
rgpio_dev->swnode = fwnode_create_software_node(properties, NULL); if (IS_ERR(rgpio_dev->swnode)) { ret = PTR_ERR(rgpio_dev->swnode); goto err_put_fwnode; }
ret = reset_create_gpio_aux_device(rgpio_dev, parent); if (ret) goto err_del_swnode;
reset_gpio_add_devlink(fwnode, rgpio_dev); list_add(&rgpio_dev->list, &reset_gpio_lookup_list);
return 0;
err_del_swnode: fwnode_remove_software_node(rgpio_dev->swnode);err_put_fwnode: fwnode_handle_put(rgpio_dev->ref_args.fwnode); kfree(rgpio_dev);
return ret;}
static struct reset_controller_dev *__reset_find_rcdev(const struct fwnode_reference_args *args, bool gpio_fallback){ struct fwnode_reference_args *rc_args; struct reset_controller_dev *rcdev;
lockdep_assert_held(&reset_list_mutex);
list_for_each_entry(rcdev, &reset_controller_list, list) { if (gpio_fallback && rcdev->dev && device_is_compatible(rcdev->dev, "reset-gpio")) { rc_args = dev_get_platdata(rcdev->dev);
if (fwnode_reference_args_equal(args, rc_args)) return rcdev; } else { if (args->fwnode == rcdev->fwnode) return rcdev; } }
return NULL;}
struct reset_control *__fwnode_reset_control_get(struct fwnode_handle *fwnode, 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 = ERR_PTR(-EINVAL); struct reset_controller_dev *rcdev; struct fwnode_reference_args args; struct of_phandle_args of_args; int rstc_id = -EINVAL; int ret;
if (!fwnode) return ERR_PTR(-EINVAL);
if (id) { index = fwnode_property_match_string(fwnode, "reset-names", id); if (index == -EILSEQ) return ERR_PTR(index); if (index < 0) return optional ? NULL : ERR_PTR(-ENOENT); }
ret = fwnode_property_get_reference_args(fwnode, "resets", "#reset-cells", 0, index, &args); if (ret == -EINVAL) return ERR_PTR(ret); if (ret) { if (!IS_ENABLED(CONFIG_RESET_GPIO)) return optional ? NULL : ERR_PTR(ret);
/* * There can be only one reset-gpio for regular devices, so * don't bother with the "reset-gpios" phandle index. */ ret = fwnode_property_get_reference_args(fwnode, "reset-gpios", "#gpio-cells", 0, 0, &args); if (ret) return optional ? NULL : ERR_PTR(ret);
gpio_fallback = true;
ret = __reset_add_reset_gpio_device(fwnode, &args); if (ret) { fwnode_handle_put(args.fwnode); return ERR_PTR(ret); } }
guard(mutex)(&reset_list_mutex);
rcdev = __reset_find_rcdev(&args, gpio_fallback); if (!rcdev) { rstc = ERR_PTR(-EPROBE_DEFER); goto out_put; }
if (WARN_ON(args.nargs != rcdev->fwnode_reset_n_cells)) { rstc = ERR_PTR(-EINVAL); goto out_put; }
if (rcdev->of_xlate && is_of_node(fwnode)) { ret = of_parse_phandle_with_args(to_of_node(fwnode), gpio_fallback ? "reset-gpios" : "resets", gpio_fallback ? "#gpio-cells" : "#reset-cells", gpio_fallback ? 0 : index, &of_args); if (ret) { rstc = ERR_PTR(ret); goto out_put; }
rstc_id = rcdev->of_xlate(rcdev, &of_args); of_node_put(of_args.np); } else if (rcdev->fwnode_xlate) { rstc_id = rcdev->fwnode_xlate(rcdev, &args); } if (rstc_id < 0) { rstc = ERR_PTR(rstc_id); goto out_put; }
flags &= ~RESET_CONTROL_FLAGS_BIT_OPTIONAL;
scoped_guard(mutex, &rcdev->lock) rstc = __reset_control_get_internal(rcdev, rstc_id, flags);
out_put: fwnode_handle_put(args.fwnode);
return rstc;}EXPORT_SYMBOL_GPL(__fwnode_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; struct fwnode_handle *fwnode = dev_fwnode(dev);
if (WARN_ON(shared && acquired)) return ERR_PTR(-EINVAL);
if (fwnode) return __fwnode_reset_control_get(fwnode, 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: while (i--) reset_control_put_internal(rstcs[i].rstc);
return ret;}EXPORT_SYMBOL_GPL(__reset_control_bulk_get);
static void reset_control_array_put(struct reset_control_array *resets){ int i;
for (i = 0; i < resets->num_rstcs; i++) reset_control_put_internal(resets->rstc[i]); 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; }
reset_control_put_internal(rstc);}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){ while (num_rstcs--) reset_control_put_internal(rstcs[num_rstcs].rstc);}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);}
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(deasserted ? devm_reset_control_release_deasserted : devm_reset_control_release, sizeof(*ptr), GFP_KERNEL); if (!ptr) return ERR_PTR(-ENOMEM);
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);
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);}
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;
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_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){ enum reset_control_flags flags; 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
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);
ret = reset_control_reset(rstc);
reset_control_put(rstc);
return ret;}EXPORT_SYMBOL_GPL(__device_reset);
/* * APIs to manage an array of reset controls. */
/** * fwnode_reset_control_get_count - Count number of resets available with a device * * @fwnode: firmware node that contains 'resets'. * * Returns positive reset count on success, or error number on failure and * on count being zero. */static int fwnode_reset_control_get_count(struct fwnode_handle *fwnode){ struct fwnode_reference_args args; int count = 0, ret;
if (!fwnode) return -EINVAL;
for (;;) { ret = fwnode_property_get_reference_args(fwnode, "resets", "#reset-cells", 0, count, &args); if (ret) { if (ret == -ENOENT) break;
return ret; }
fwnode_handle_put(args.fwnode); count++; }
if (count == 0) count = -ENOENT;
return count;}
/** * fwnode_reset_control_array_get - Get a list of reset controls using * a firmware node. * * @fwnode: firmware 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 *fwnode_reset_control_array_get(struct fwnode_handle *fwnode, 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 = fwnode_reset_control_get_count(fwnode); if (num < 0) return optional ? NULL : ERR_PTR(num);
resets = kzalloc_flex(*resets, rstc, num); if (!resets) return ERR_PTR(-ENOMEM); resets->num_rstcs = num;
for (i = 0; i < num; i++) { rstc = __fwnode_reset_control_get(fwnode, NULL, i, flags); if (IS_ERR(rstc)) goto err_rst; resets->rstc[i] = rstc; } resets->base.array = true;
return &resets->base;
err_rst: while (--i >= 0) reset_control_put_internal(resets->rstc[i]);
kfree(resets);
return rstc;}EXPORT_SYMBOL_GPL(fwnode_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 = fwnode_reset_control_array_get(dev_fwnode(dev), 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){ struct fwnode_handle *fwnode = dev_fwnode(dev);
if (fwnode) return fwnode_reset_control_get_count(fwnode);
return -ENOENT;}EXPORT_SYMBOL_GPL(reset_control_get_count);