linux/drivers/reset/core.c

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/*
* Reset Controller framework
*
* Copyright 2013 Philipp Zabel, Pengutronix
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/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/reset.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
static DEFINE_MUTEX(reset_list_mutex);
static LIST_HEAD(reset_controller_list);
reset: add support for non-DT systems The reset framework only supports device-tree. There are some platforms however, which need to use it even in legacy, board-file based mode. An example of such architecture is the DaVinci family of SoCs which supports both device tree and legacy boot modes and we don't want to introduce any regressions. We're currently working on converting the platform from its hand-crafted clock API to using the common clock framework. Part of the overhaul will be representing the chip's power sleep controller's reset lines using the reset framework. This changeset extends the core reset code with a new reset lookup entry structure. It contains data allowing the reset core to associate reset lines with devices by comparing the dev_id and con_id strings. It also provides a function allowing drivers to register lookup entries with the framework. The new lookup function is only called as a fallback in case the of_node field is NULL and doesn't change anything for current users. Tested with a dummy reset driver with several lookup entries. An example lookup table registration from a driver can be found below: static struct reset_control_lookup foobar_reset_lookup[] = { RESET_LOOKUP("foo.0", "foo", 15), RESET_LOOKUP("bar.0", NULL, 5), }; foobar_probe() { ... reset_controller_add_lookup(&rcdev, foobar_reset_lookup, ARRAY_SIZE(foobar_reset_lookup)); ... } Cc: Sekhar Nori <nsekhar@ti.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: David Lechner <david@lechnology.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2018-02-28 13:08:57 +00:00
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
* @shared: Is this a shared (1), or an exclusive (0) reset_control?
* @deassert_cnt: 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 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[];
};
/**
* of_reset_simple_xlate - translate reset_spec to the reset line number
* @rcdev: a pointer to the reset controller device
* @reset_spec: reset line specifier as found in the device tree
* @flags: a flags pointer to fill in (optional)
*
* This simple translation function should be used for reset controllers
* with 1:1 mapping, where reset lines can be indexed by number without gaps.
*/
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) {
*rcdevp = rcdev;
devres_add(dev, rcdevp);
} else {
devres_free(rcdevp);
}
return ret;
}
EXPORT_SYMBOL_GPL(devm_reset_controller_register);
reset: add support for non-DT systems The reset framework only supports device-tree. There are some platforms however, which need to use it even in legacy, board-file based mode. An example of such architecture is the DaVinci family of SoCs which supports both device tree and legacy boot modes and we don't want to introduce any regressions. We're currently working on converting the platform from its hand-crafted clock API to using the common clock framework. Part of the overhaul will be representing the chip's power sleep controller's reset lines using the reset framework. This changeset extends the core reset code with a new reset lookup entry structure. It contains data allowing the reset core to associate reset lines with devices by comparing the dev_id and con_id strings. It also provides a function allowing drivers to register lookup entries with the framework. The new lookup function is only called as a fallback in case the of_node field is NULL and doesn't change anything for current users. Tested with a dummy reset driver with several lookup entries. An example lookup table registration from a driver can be found below: static struct reset_control_lookup foobar_reset_lookup[] = { RESET_LOOKUP("foo.0", "foo", 15), RESET_LOOKUP("bar.0", NULL, 5), }; foobar_probe() { ... reset_controller_add_lookup(&rcdev, foobar_reset_lookup, ARRAY_SIZE(foobar_reset_lookup)); ... } Cc: Sekhar Nori <nsekhar@ti.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: David Lechner <david@lechnology.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2018-02-28 13:08:57 +00:00
/**
* 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,
reset: add support for non-DT systems The reset framework only supports device-tree. There are some platforms however, which need to use it even in legacy, board-file based mode. An example of such architecture is the DaVinci family of SoCs which supports both device tree and legacy boot modes and we don't want to introduce any regressions. We're currently working on converting the platform from its hand-crafted clock API to using the common clock framework. Part of the overhaul will be representing the chip's power sleep controller's reset lines using the reset framework. This changeset extends the core reset code with a new reset lookup entry structure. It contains data allowing the reset core to associate reset lines with devices by comparing the dev_id and con_id strings. It also provides a function allowing drivers to register lookup entries with the framework. The new lookup function is only called as a fallback in case the of_node field is NULL and doesn't change anything for current users. Tested with a dummy reset driver with several lookup entries. An example lookup table registration from a driver can be found below: static struct reset_control_lookup foobar_reset_lookup[] = { RESET_LOOKUP("foo.0", "foo", 15), RESET_LOOKUP("bar.0", NULL, 5), }; foobar_probe() { ... reset_controller_add_lookup(&rcdev, foobar_reset_lookup, ARRAY_SIZE(foobar_reset_lookup)); ... } Cc: Sekhar Nori <nsekhar@ti.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: David Lechner <david@lechnology.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2018-02-28 13:08:57 +00:00
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",
reset: add support for non-DT systems The reset framework only supports device-tree. There are some platforms however, which need to use it even in legacy, board-file based mode. An example of such architecture is the DaVinci family of SoCs which supports both device tree and legacy boot modes and we don't want to introduce any regressions. We're currently working on converting the platform from its hand-crafted clock API to using the common clock framework. Part of the overhaul will be representing the chip's power sleep controller's reset lines using the reset framework. This changeset extends the core reset code with a new reset lookup entry structure. It contains data allowing the reset core to associate reset lines with devices by comparing the dev_id and con_id strings. It also provides a function allowing drivers to register lookup entries with the framework. The new lookup function is only called as a fallback in case the of_node field is NULL and doesn't change anything for current users. Tested with a dummy reset driver with several lookup entries. An example lookup table registration from a driver can be found below: static struct reset_control_lookup foobar_reset_lookup[] = { RESET_LOOKUP("foo.0", "foo", 15), RESET_LOOKUP("bar.0", NULL, 5), }; foobar_probe() { ... reset_controller_add_lookup(&rcdev, foobar_reset_lookup, ARRAY_SIZE(foobar_reset_lookup)); ... } Cc: Sekhar Nori <nsekhar@ti.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: David Lechner <david@lechnology.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2018-02-28 13:08:57 +00:00
__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_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 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;
}
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_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.
* return 0.
*
* 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;
}
return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
}
EXPORT_SYMBOL_GPL(reset_control_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.
* return 0.
*
* 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;
}
/*
* 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_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);
static struct reset_control *__reset_control_get_internal(
struct reset_controller_dev *rcdev,
unsigned int index, bool shared)
{
struct reset_control *rstc;
lockdep_assert_held(&reset_list_mutex);
list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
if (rstc->id == index) {
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);
try_module_get(rcdev->owner);
rstc->rcdev = rcdev;
list_add(&rstc->list, &rcdev->reset_control_head);
rstc->id = index;
kref_init(&rstc->refcnt);
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);
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)
{
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);
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;
}
reset: add support for non-DT systems The reset framework only supports device-tree. There are some platforms however, which need to use it even in legacy, board-file based mode. An example of such architecture is the DaVinci family of SoCs which supports both device tree and legacy boot modes and we don't want to introduce any regressions. We're currently working on converting the platform from its hand-crafted clock API to using the common clock framework. Part of the overhaul will be representing the chip's power sleep controller's reset lines using the reset framework. This changeset extends the core reset code with a new reset lookup entry structure. It contains data allowing the reset core to associate reset lines with devices by comparing the dev_id and con_id strings. It also provides a function allowing drivers to register lookup entries with the framework. The new lookup function is only called as a fallback in case the of_node field is NULL and doesn't change anything for current users. Tested with a dummy reset driver with several lookup entries. An example lookup table registration from a driver can be found below: static struct reset_control_lookup foobar_reset_lookup[] = { RESET_LOOKUP("foo.0", "foo", 15), RESET_LOOKUP("bar.0", NULL, 5), }; foobar_probe() { ... reset_controller_add_lookup(&rcdev, foobar_reset_lookup, ARRAY_SIZE(foobar_reset_lookup)); ... } Cc: Sekhar Nori <nsekhar@ti.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: David Lechner <david@lechnology.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2018-02-28 13:08:57 +00:00
static struct reset_control *
__reset_control_get_from_lookup(struct device *dev, const char *con_id,
bool shared, bool optional)
{
const struct reset_control_lookup *lookup;
struct reset_controller_dev *rcdev;
reset: add support for non-DT systems The reset framework only supports device-tree. There are some platforms however, which need to use it even in legacy, board-file based mode. An example of such architecture is the DaVinci family of SoCs which supports both device tree and legacy boot modes and we don't want to introduce any regressions. We're currently working on converting the platform from its hand-crafted clock API to using the common clock framework. Part of the overhaul will be representing the chip's power sleep controller's reset lines using the reset framework. This changeset extends the core reset code with a new reset lookup entry structure. It contains data allowing the reset core to associate reset lines with devices by comparing the dev_id and con_id strings. It also provides a function allowing drivers to register lookup entries with the framework. The new lookup function is only called as a fallback in case the of_node field is NULL and doesn't change anything for current users. Tested with a dummy reset driver with several lookup entries. An example lookup table registration from a driver can be found below: static struct reset_control_lookup foobar_reset_lookup[] = { RESET_LOOKUP("foo.0", "foo", 15), RESET_LOOKUP("bar.0", NULL, 5), }; foobar_probe() { ... reset_controller_add_lookup(&rcdev, foobar_reset_lookup, ARRAY_SIZE(foobar_reset_lookup)); ... } Cc: Sekhar Nori <nsekhar@ti.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: David Lechner <david@lechnology.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2018-02-28 13:08:57 +00:00
const char *dev_id = dev_name(dev);
struct reset_control *rstc = NULL;
if (!dev)
return ERR_PTR(-EINVAL);
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,
reset: add support for non-DT systems The reset framework only supports device-tree. There are some platforms however, which need to use it even in legacy, board-file based mode. An example of such architecture is the DaVinci family of SoCs which supports both device tree and legacy boot modes and we don't want to introduce any regressions. We're currently working on converting the platform from its hand-crafted clock API to using the common clock framework. Part of the overhaul will be representing the chip's power sleep controller's reset lines using the reset framework. This changeset extends the core reset code with a new reset lookup entry structure. It contains data allowing the reset core to associate reset lines with devices by comparing the dev_id and con_id strings. It also provides a function allowing drivers to register lookup entries with the framework. The new lookup function is only called as a fallback in case the of_node field is NULL and doesn't change anything for current users. Tested with a dummy reset driver with several lookup entries. An example lookup table registration from a driver can be found below: static struct reset_control_lookup foobar_reset_lookup[] = { RESET_LOOKUP("foo.0", "foo", 15), RESET_LOOKUP("bar.0", NULL, 5), }; foobar_probe() { ... reset_controller_add_lookup(&rcdev, foobar_reset_lookup, ARRAY_SIZE(foobar_reset_lookup)); ... } Cc: Sekhar Nori <nsekhar@ti.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: David Lechner <david@lechnology.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2018-02-28 13:08:57 +00:00
lookup->index,
shared);
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)
{
if (dev->of_node)
return __of_reset_control_get(dev->of_node, id, index, shared,
optional);
reset: add support for non-DT systems The reset framework only supports device-tree. There are some platforms however, which need to use it even in legacy, board-file based mode. An example of such architecture is the DaVinci family of SoCs which supports both device tree and legacy boot modes and we don't want to introduce any regressions. We're currently working on converting the platform from its hand-crafted clock API to using the common clock framework. Part of the overhaul will be representing the chip's power sleep controller's reset lines using the reset framework. This changeset extends the core reset code with a new reset lookup entry structure. It contains data allowing the reset core to associate reset lines with devices by comparing the dev_id and con_id strings. It also provides a function allowing drivers to register lookup entries with the framework. The new lookup function is only called as a fallback in case the of_node field is NULL and doesn't change anything for current users. Tested with a dummy reset driver with several lookup entries. An example lookup table registration from a driver can be found below: static struct reset_control_lookup foobar_reset_lookup[] = { RESET_LOOKUP("foo.0", "foo", 15), RESET_LOOKUP("bar.0", NULL, 5), }; foobar_probe() { ... reset_controller_add_lookup(&rcdev, foobar_reset_lookup, ARRAY_SIZE(foobar_reset_lookup)); ... } Cc: Sekhar Nori <nsekhar@ti.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: David Lechner <david@lechnology.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2018-02-28 13:08:57 +00:00
return __reset_control_get_from_lookup(dev, id, shared, optional);
}
EXPORT_SYMBOL_GPL(__reset_control_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);
}
/**
* 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);
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)
{
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);
if (!IS_ERR(rstc)) {
*ptr = rstc;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return rstc;
}
EXPORT_SYMBOL_GPL(__devm_reset_control_get);
/**
* device_reset - find reset controller associated with the device
* and perform reset
* @dev: device to be reset by the controller
* @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.
*/
int __device_reset(struct device *dev, bool optional)
{
struct reset_control *rstc;
int ret;
rstc = __reset_control_get(dev, NULL, 0, 0, optional);
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
*
* Returns pointer to allocated reset_control_array on success or
* error on failure
*/
struct reset_control *
of_reset_control_array_get(struct device_node *np, bool shared, bool optional)
{
struct reset_control_array *resets;
struct reset_control *rstc;
int num, i;
num = of_reset_control_get_count(np);
if (num < 0)
return optional ? NULL : ERR_PTR(num);
treewide: Use struct_size() for kmalloc()-family One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); This patch makes the changes for kmalloc()-family (and kvmalloc()-family) uses. It was done via automatic conversion with manual review for the "CHECKME" non-standard cases noted below, using the following Coccinelle script: // pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len * // sizeof *pkey_cache->table, GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // Same pattern, but can't trivially locate the trailing element name, // or variable name. @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; expression SOMETHING, COUNT, ELEMENT; @@ - alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP) + alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-05-08 20:45:50 +00:00
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);
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_array on success or
* error on failure
*/
struct reset_control *
devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
{
struct reset_control **devres;
struct reset_control *rstc;
devres = devres_alloc(devm_reset_control_release, sizeof(*devres),
GFP_KERNEL);
if (!devres)
return ERR_PTR(-ENOMEM);
rstc = of_reset_control_array_get(dev->of_node, shared, optional);
if (IS_ERR(rstc)) {
devres_free(devres);
return rstc;
}
*devres = rstc;
devres_add(dev, devres);
return rstc;
}
EXPORT_SYMBOL_GPL(devm_reset_control_array_get);