Reset controller changes for v4.7

- add support for shared reset controls
 - remove global variables from the lpc18xx driver
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Merge tag 'reset-for-4.7' of git://git.pengutronix.de/git/pza/linux into next/drivers

Reset controller changes for v4.7

- add support for shared reset controls
- remove global variables from the lpc18xx driver

* tag 'reset-for-4.7' of git://git.pengutronix.de/git/pza/linux:
  reset: lpc18xx: get rid of global variables for restart notifier
  reset: Add support for shared reset controls
  reset: Share struct reset_control between reset_control_get calls
  reset: Make [of_]reset_control_get[_foo] functions wrappers

Signed-off-by: Olof Johansson <olof@lixom.net>
This commit is contained in:
Olof Johansson 2016-04-13 11:11:11 -07:00
commit f8ed1e1a45
4 changed files with 291 additions and 142 deletions

View File

@ -8,6 +8,7 @@
* 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>
@ -18,19 +19,27 @@
#include <linux/reset-controller.h>
#include <linux/slab.h>
static DEFINE_MUTEX(reset_controller_list_mutex);
static DEFINE_MUTEX(reset_list_mutex);
static LIST_HEAD(reset_controller_list);
/**
* 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
*/
struct reset_control {
struct reset_controller_dev *rcdev;
struct list_head list;
unsigned int id;
unsigned int refcnt;
int shared;
atomic_t deassert_count;
};
/**
@ -62,9 +71,11 @@ int reset_controller_register(struct reset_controller_dev *rcdev)
rcdev->of_xlate = of_reset_simple_xlate;
}
mutex_lock(&reset_controller_list_mutex);
INIT_LIST_HEAD(&rcdev->reset_control_head);
mutex_lock(&reset_list_mutex);
list_add(&rcdev->list, &reset_controller_list);
mutex_unlock(&reset_controller_list_mutex);
mutex_unlock(&reset_list_mutex);
return 0;
}
@ -76,18 +87,23 @@ EXPORT_SYMBOL_GPL(reset_controller_register);
*/
void reset_controller_unregister(struct reset_controller_dev *rcdev)
{
mutex_lock(&reset_controller_list_mutex);
mutex_lock(&reset_list_mutex);
list_del(&rcdev->list);
mutex_unlock(&reset_controller_list_mutex);
mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_controller_unregister);
/**
* reset_control_reset - reset the controlled device
* @rstc: reset controller
*
* Calling this on a shared reset controller is an error.
*/
int reset_control_reset(struct reset_control *rstc)
{
if (WARN_ON(rstc->shared))
return -EINVAL;
if (rstc->rcdev->ops->reset)
return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
@ -98,26 +114,48 @@ 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.
*/
int reset_control_assert(struct reset_control *rstc)
{
if (rstc->rcdev->ops->assert)
return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
if (!rstc->rcdev->ops->assert)
return -ENOTSUPP;
if (rstc->shared) {
if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
return -EINVAL;
if (atomic_dec_return(&rstc->deassert_count) != 0)
return 0;
}
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.
*/
int reset_control_deassert(struct reset_control *rstc)
{
if (rstc->rcdev->ops->deassert)
return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
if (!rstc->rcdev->ops->deassert)
return -ENOTSUPP;
if (rstc->shared) {
if (atomic_inc_return(&rstc->deassert_count) != 1)
return 0;
}
return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
}
EXPORT_SYMBOL_GPL(reset_control_deassert);
@ -136,18 +174,54 @@ int reset_control_status(struct reset_control *rstc)
}
EXPORT_SYMBOL_GPL(reset_control_status);
/**
* of_reset_control_get_by_index - Lookup and obtain a reference to a reset
* controller by index.
* @node: device to be reset by the controller
* @index: index of the reset controller
*
* This is to be used to perform a list of resets for a device or power domain
* in whatever order. Returns a struct reset_control or IS_ERR() condition
* containing errno.
*/
struct reset_control *of_reset_control_get_by_index(struct device_node *node,
int index)
static struct reset_control *__reset_control_get(
struct reset_controller_dev *rcdev,
unsigned int index, int 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);
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;
rstc->refcnt = 1;
rstc->shared = shared;
return rstc;
}
static void __reset_control_put(struct reset_control *rstc)
{
lockdep_assert_held(&reset_list_mutex);
if (--rstc->refcnt)
return;
module_put(rstc->rcdev->owner);
list_del(&rstc->list);
kfree(rstc);
}
struct reset_control *__of_reset_control_get(struct device_node *node,
const char *id, int index, int shared)
{
struct reset_control *rstc;
struct reset_controller_dev *r, *rcdev;
@ -155,12 +229,22 @@ struct reset_control *of_reset_control_get_by_index(struct device_node *node,
int rstc_id;
int ret;
if (!node)
return ERR_PTR(-EINVAL);
if (id) {
index = of_property_match_string(node,
"reset-names", id);
if (index < 0)
return ERR_PTR(-ENOENT);
}
ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
index, &args);
if (ret)
return ERR_PTR(ret);
mutex_lock(&reset_controller_list_mutex);
mutex_lock(&reset_list_mutex);
rcdev = NULL;
list_for_each_entry(r, &reset_controller_list, list) {
if (args.np == r->of_node) {
@ -171,78 +255,29 @@ struct reset_control *of_reset_control_get_by_index(struct device_node *node,
of_node_put(args.np);
if (!rcdev) {
mutex_unlock(&reset_controller_list_mutex);
mutex_unlock(&reset_list_mutex);
return ERR_PTR(-EPROBE_DEFER);
}
if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
mutex_unlock(&reset_controller_list_mutex);
mutex_unlock(&reset_list_mutex);
return ERR_PTR(-EINVAL);
}
rstc_id = rcdev->of_xlate(rcdev, &args);
if (rstc_id < 0) {
mutex_unlock(&reset_controller_list_mutex);
mutex_unlock(&reset_list_mutex);
return ERR_PTR(rstc_id);
}
try_module_get(rcdev->owner);
mutex_unlock(&reset_controller_list_mutex);
/* reset_list_mutex also protects the rcdev's reset_control list */
rstc = __reset_control_get(rcdev, rstc_id, shared);
rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
if (!rstc) {
module_put(rcdev->owner);
return ERR_PTR(-ENOMEM);
}
rstc->rcdev = rcdev;
rstc->id = rstc_id;
mutex_unlock(&reset_list_mutex);
return rstc;
}
EXPORT_SYMBOL_GPL(of_reset_control_get_by_index);
/**
* of_reset_control_get - Lookup and obtain a reference to a reset controller.
* @node: device to be reset by the controller
* @id: reset line name
*
* Returns a struct reset_control or IS_ERR() condition containing errno.
*
* Use of id names is optional.
*/
struct reset_control *of_reset_control_get(struct device_node *node,
const char *id)
{
int index = 0;
if (id) {
index = of_property_match_string(node,
"reset-names", id);
if (index < 0)
return ERR_PTR(-ENOENT);
}
return of_reset_control_get_by_index(node, index);
}
EXPORT_SYMBOL_GPL(of_reset_control_get);
/**
* reset_control_get - Lookup and obtain a reference to a reset controller.
* @dev: device to be reset by the controller
* @id: reset line name
*
* Returns a struct reset_control or IS_ERR() condition containing errno.
*
* Use of id names is optional.
*/
struct reset_control *reset_control_get(struct device *dev, const char *id)
{
if (!dev)
return ERR_PTR(-EINVAL);
return of_reset_control_get(dev->of_node, id);
}
EXPORT_SYMBOL_GPL(reset_control_get);
EXPORT_SYMBOL_GPL(__of_reset_control_get);
/**
* reset_control_put - free the reset controller
@ -254,8 +289,9 @@ void reset_control_put(struct reset_control *rstc)
if (IS_ERR(rstc))
return;
module_put(rstc->rcdev->owner);
kfree(rstc);
mutex_lock(&reset_list_mutex);
__reset_control_put(rstc);
mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_control_put);
@ -264,16 +300,8 @@ static void devm_reset_control_release(struct device *dev, void *res)
reset_control_put(*(struct reset_control **)res);
}
/**
* devm_reset_control_get - resource managed reset_control_get()
* @dev: device to be reset by the controller
* @id: reset line name
*
* Managed reset_control_get(). For reset controllers returned from this
* function, reset_control_put() is called automatically on driver detach.
* See reset_control_get() for more information.
*/
struct reset_control *devm_reset_control_get(struct device *dev, const char *id)
struct reset_control *__devm_reset_control_get(struct device *dev,
const char *id, int index, int shared)
{
struct reset_control **ptr, *rstc;
@ -282,7 +310,8 @@ struct reset_control *devm_reset_control_get(struct device *dev, const char *id)
if (!ptr)
return ERR_PTR(-ENOMEM);
rstc = reset_control_get(dev, id);
rstc = __of_reset_control_get(dev ? dev->of_node : NULL,
id, index, shared);
if (!IS_ERR(rstc)) {
*ptr = rstc;
devres_add(dev, ptr);
@ -292,7 +321,7 @@ struct reset_control *devm_reset_control_get(struct device *dev, const char *id)
return rstc;
}
EXPORT_SYMBOL_GPL(devm_reset_control_get);
EXPORT_SYMBOL_GPL(__devm_reset_control_get);
/**
* device_reset - find reset controller associated with the device

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@ -35,6 +35,7 @@
struct lpc18xx_rgu_data {
struct reset_controller_dev rcdev;
struct notifier_block restart_nb;
struct clk *clk_delay;
struct clk *clk_reg;
void __iomem *base;
@ -44,12 +45,13 @@ struct lpc18xx_rgu_data {
#define to_rgu_data(p) container_of(p, struct lpc18xx_rgu_data, rcdev)
static void __iomem *rgu_base;
static int lpc18xx_rgu_restart(struct notifier_block *this, unsigned long mode,
static int lpc18xx_rgu_restart(struct notifier_block *nb, unsigned long mode,
void *cmd)
{
writel(BIT(LPC18XX_RGU_CORE_RST), rgu_base + LPC18XX_RGU_CTRL0);
struct lpc18xx_rgu_data *rc = container_of(nb, struct lpc18xx_rgu_data,
restart_nb);
writel(BIT(LPC18XX_RGU_CORE_RST), rc->base + LPC18XX_RGU_CTRL0);
mdelay(2000);
pr_emerg("%s: unable to restart system\n", __func__);
@ -57,11 +59,6 @@ static int lpc18xx_rgu_restart(struct notifier_block *this, unsigned long mode,
return NOTIFY_DONE;
}
static struct notifier_block lpc18xx_rgu_restart_nb = {
.notifier_call = lpc18xx_rgu_restart,
.priority = 192,
};
/*
* The LPC18xx RGU has mostly self-deasserting resets except for the
* two reset lines going to the internal Cortex-M0 cores.
@ -205,8 +202,9 @@ static int lpc18xx_rgu_probe(struct platform_device *pdev)
goto dis_clks;
}
rgu_base = rc->base;
ret = register_restart_handler(&lpc18xx_rgu_restart_nb);
rc->restart_nb.priority = 192,
rc->restart_nb.notifier_call = lpc18xx_rgu_restart,
ret = register_restart_handler(&rc->restart_nb);
if (ret)
dev_warn(&pdev->dev, "failed to register restart handler\n");
@ -225,7 +223,7 @@ static int lpc18xx_rgu_remove(struct platform_device *pdev)
struct lpc18xx_rgu_data *rc = platform_get_drvdata(pdev);
int ret;
ret = unregister_restart_handler(&lpc18xx_rgu_restart_nb);
ret = unregister_restart_handler(&rc->restart_nb);
if (ret)
dev_warn(&pdev->dev, "failed to unregister restart handler\n");

View File

@ -31,6 +31,7 @@ struct of_phandle_args;
* @ops: a pointer to device specific struct reset_control_ops
* @owner: kernel module of the reset controller driver
* @list: internal list of reset controller devices
* @reset_control_head: head of internal list of requested reset controls
* @of_node: corresponding device tree node as phandle target
* @of_reset_n_cells: number of cells in reset line specifiers
* @of_xlate: translation function to translate from specifier as found in the
@ -41,6 +42,7 @@ struct reset_controller_dev {
const struct reset_control_ops *ops;
struct module *owner;
struct list_head list;
struct list_head reset_control_head;
struct device_node *of_node;
int of_reset_n_cells;
int (*of_xlate)(struct reset_controller_dev *rcdev,

View File

@ -1,8 +1,8 @@
#ifndef _LINUX_RESET_H_
#define _LINUX_RESET_H_
struct device;
struct device_node;
#include <linux/device.h>
struct reset_control;
#ifdef CONFIG_RESET_CONTROLLER
@ -12,9 +12,11 @@ int reset_control_assert(struct reset_control *rstc);
int reset_control_deassert(struct reset_control *rstc);
int reset_control_status(struct reset_control *rstc);
struct reset_control *reset_control_get(struct device *dev, const char *id);
struct reset_control *__of_reset_control_get(struct device_node *node,
const char *id, int index, int shared);
void reset_control_put(struct reset_control *rstc);
struct reset_control *devm_reset_control_get(struct device *dev, const char *id);
struct reset_control *__devm_reset_control_get(struct device *dev,
const char *id, int index, int shared);
int __must_check device_reset(struct device *dev);
@ -23,24 +25,6 @@ static inline int device_reset_optional(struct device *dev)
return device_reset(dev);
}
static inline struct reset_control *reset_control_get_optional(
struct device *dev, const char *id)
{
return reset_control_get(dev, id);
}
static inline struct reset_control *devm_reset_control_get_optional(
struct device *dev, const char *id)
{
return devm_reset_control_get(dev, id);
}
struct reset_control *of_reset_control_get(struct device_node *node,
const char *id);
struct reset_control *of_reset_control_get_by_index(
struct device_node *node, int index);
#else
static inline int reset_control_reset(struct reset_control *rstc)
@ -77,44 +61,180 @@ static inline int device_reset_optional(struct device *dev)
return -ENOTSUPP;
}
static inline struct reset_control *__must_check reset_control_get(
struct device *dev, const char *id)
static inline struct reset_control *__of_reset_control_get(
struct device_node *node,
const char *id, int index, int shared)
{
WARN_ON(1);
return ERR_PTR(-EINVAL);
}
static inline struct reset_control *__must_check devm_reset_control_get(
static inline struct reset_control *__devm_reset_control_get(
struct device *dev,
const char *id, int index, int shared)
{
return ERR_PTR(-EINVAL);
}
#endif /* CONFIG_RESET_CONTROLLER */
/**
* reset_control_get - Lookup and obtain an exclusive reference to a
* reset controller.
* @dev: device to be reset by the controller
* @id: reset line name
*
* Returns a struct reset_control or IS_ERR() condition containing errno.
* If this function is called more then once for the same reset_control it will
* return -EBUSY.
*
* See reset_control_get_shared for details on shared references to
* reset-controls.
*
* Use of id names is optional.
*/
static inline struct reset_control *__must_check reset_control_get(
struct device *dev, const char *id)
{
#ifndef CONFIG_RESET_CONTROLLER
WARN_ON(1);
return ERR_PTR(-EINVAL);
#endif
return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0);
}
static inline struct reset_control *reset_control_get_optional(
struct device *dev, const char *id)
{
return ERR_PTR(-ENOTSUPP);
return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0);
}
/**
* reset_control_get_shared - Lookup and obtain a shared reference to a
* reset controller.
* @dev: device to be reset by the controller
* @id: reset line name
*
* Returns a struct reset_control or IS_ERR() condition containing errno.
* This function is intended for use with reset-controls which are shared
* between hardware-blocks.
*
* When a reset-control is shared, the behavior of reset_control_assert /
* deassert is changed, the reset-core will keep track of a deassert_count
* and only (re-)assert the reset after reset_control_assert has been called
* as many times as reset_control_deassert was called. Also see the remark
* about shared reset-controls in the reset_control_assert docs.
*
* Calling reset_control_assert without first calling reset_control_deassert
* is not allowed on a shared reset control. Calling reset_control_reset is
* also not allowed on a shared reset control.
*
* Use of id names is optional.
*/
static inline struct reset_control *reset_control_get_shared(
struct device *dev, const char *id)
{
return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 1);
}
/**
* of_reset_control_get - Lookup and obtain an exclusive reference to a
* reset controller.
* @node: device to be reset by the controller
* @id: reset line name
*
* Returns a struct reset_control or IS_ERR() condition containing errno.
*
* Use of id names is optional.
*/
static inline struct reset_control *of_reset_control_get(
struct device_node *node, const char *id)
{
return __of_reset_control_get(node, id, 0, 0);
}
/**
* of_reset_control_get_by_index - Lookup and obtain an exclusive reference to
* a reset controller by index.
* @node: device to be reset by the controller
* @index: index of the reset controller
*
* This is to be used to perform a list of resets for a device or power domain
* in whatever order. Returns a struct reset_control or IS_ERR() condition
* containing errno.
*/
static inline struct reset_control *of_reset_control_get_by_index(
struct device_node *node, int index)
{
return __of_reset_control_get(node, NULL, index, 0);
}
/**
* devm_reset_control_get - resource managed reset_control_get()
* @dev: device to be reset by the controller
* @id: reset line name
*
* Managed reset_control_get(). For reset controllers returned from this
* function, reset_control_put() is called automatically on driver detach.
* See reset_control_get() for more information.
*/
static inline struct reset_control *__must_check devm_reset_control_get(
struct device *dev, const char *id)
{
#ifndef CONFIG_RESET_CONTROLLER
WARN_ON(1);
#endif
return __devm_reset_control_get(dev, id, 0, 0);
}
static inline struct reset_control *devm_reset_control_get_optional(
struct device *dev, const char *id)
{
return ERR_PTR(-ENOTSUPP);
return __devm_reset_control_get(dev, id, 0, 0);
}
static inline struct reset_control *of_reset_control_get(
struct device_node *node, const char *id)
/**
* devm_reset_control_get_by_index - resource managed reset_control_get
* @dev: device to be reset by the controller
* @index: index of the reset controller
*
* Managed reset_control_get(). For reset controllers returned from this
* function, reset_control_put() is called automatically on driver detach.
* See reset_control_get() for more information.
*/
static inline struct reset_control *devm_reset_control_get_by_index(
struct device *dev, int index)
{
return ERR_PTR(-ENOTSUPP);
return __devm_reset_control_get(dev, NULL, index, 0);
}
static inline struct reset_control *of_reset_control_get_by_index(
struct device_node *node, int index)
/**
* devm_reset_control_get_shared - resource managed reset_control_get_shared()
* @dev: device to be reset by the controller
* @id: reset line name
*
* Managed reset_control_get_shared(). For reset controllers returned from
* this function, reset_control_put() is called automatically on driver detach.
* See reset_control_get_shared() for more information.
*/
static inline struct reset_control *devm_reset_control_get_shared(
struct device *dev, const char *id)
{
return ERR_PTR(-ENOTSUPP);
return __devm_reset_control_get(dev, id, 0, 1);
}
#endif /* CONFIG_RESET_CONTROLLER */
/**
* devm_reset_control_get_shared_by_index - resource managed
* reset_control_get_shared
* @dev: device to be reset by the controller
* @index: index of the reset controller
*
* Managed reset_control_get_shared(). For reset controllers returned from
* this function, reset_control_put() is called automatically on driver detach.
* See reset_control_get_shared() for more information.
*/
static inline struct reset_control *devm_reset_control_get_shared_by_index(
struct device *dev, int index)
{
return __devm_reset_control_get(dev, NULL, index, 1);
}
#endif