linux/drivers/reset/core.c
Clément Léger a05f87270e reset: core: add get_device()/put_device on rcdev
Since the rcdev structure is allocated by the reset controller drivers
themselves, they need to exists as long as there is a consumer. A call to
module_get() is already existing but that does not work when using
device-tree overlays. In order to guarantee that the underlying reset
controller device does not vanish while using it, add a get_device() call
when retrieving a reset control from a reset controller device and a
put_device() when releasing that control.

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240808154658.247873-8-herve.codina@bootlin.com
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2024-09-02 12:02:41 +02:00

1483 lines
37 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Reset Controller framework
*
* Copyright 2013 Philipp Zabel, Pengutronix
*/
#include <linux/atomic.h>
#include <linux/cleanup.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/machine.h>
#include <linux/idr.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/acpi.h>
#include <linux/platform_device.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);
/* 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 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
* @list: list entry for the reset_gpio_lookup_list
*/
struct reset_gpio_lookup {
struct of_phandle_args of_args;
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
*
* 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_node && rcdev->of_args)
return -EINVAL;
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;
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 int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
unsigned int gpio,
unsigned int of_flags)
{
const struct fwnode_handle *fwnode = of_fwnode_handle(np);
unsigned int lookup_flags;
const char *label_tmp;
/*
* 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.
*/
if (of_flags > GPIO_ACTIVE_LOW) {
pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
of_flags, gpio);
return -EINVAL;
}
struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
if (!gdev)
return -EPROBE_DEFER;
label_tmp = gpio_device_get_label(gdev);
if (!label_tmp)
return -EINVAL;
char *label __free(kfree) = kstrdup(label_tmp, GFP_KERNEL);
if (!label)
return -ENOMEM;
/* Size: one lookup entry plus sentinel */
struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2),
GFP_KERNEL);
if (!lookup)
return -ENOMEM;
lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id);
if (!lookup->dev_id)
return -ENOMEM;
lookup_flags = GPIO_PERSISTENT;
lookup_flags |= of_flags & GPIO_ACTIVE_LOW;
lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",
lookup_flags);
/* Not freed on success, because it is persisent subsystem data. */
gpiod_add_lookup_table(no_free_ptr(lookup));
return 0;
}
/*
* @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 reset_gpio_lookup *rgpio_dev;
struct platform_device *pdev;
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);
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 */
}
}
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;
}
ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0],
args->args[1]);
if (ret < 0)
goto err_kfree;
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);
pdev = platform_device_register_data(NULL, "reset-gpio", id,
&rgpio_dev->of_args,
sizeof(rgpio_dev->of_args));
ret = PTR_ERR_OR_ZERO(pdev);
if (ret)
goto err_put;
list_add(&rgpio_dev->list, &reset_gpio_lookup_list);
return 0;
err_put:
of_node_put(rgpio_dev->of_args.np);
err_kfree:
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,
bool shared, bool optional, bool acquired)
{
bool gpio_fallback = false;
struct reset_control *rstc;
struct reset_controller_dev *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) {
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 = 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;
}
}
mutex_lock(&reset_list_mutex);
rcdev = __reset_find_rcdev(&args, gpio_fallback);
if (!rcdev) {
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) {
rstc = ERR_PTR(rstc_id);
goto out_unlock;
}
/* reset_list_mutex also protects the rcdev's reset_control list */
rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
out_unlock:
mutex_unlock(&reset_list_mutex);
out_put:
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);
resets->num_rstcs = num;
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->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);