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Commit fb7737e9 authored by Suman Anna's avatar Suman Anna Committed by Ohad Ben-Cohen
Browse files

hwspinlock/core: add device tree support 



This patch adds a new OF-friendly API of_hwspin_lock_get_id()
for hwspinlock clients to use/request locks from a hwspinlock
device instantiated through a device-tree blob. This new API
can be used by hwspinlock clients to get the id for a specific
lock using the phandle + args specifier, so that it can be
requested using the available hwspin_lock_request_specific()
API.

Signed-off-by: default avatarSuman Anna <s-anna@ti.com>
Reviewed-by: default avatarBjorn Andersson <bjorn.andersson@sonymobile.com>
[small comment clarification]
Signed-off-by: default avatarOhad Ben-Cohen <ohad@wizery.com>
parent 0ce8cf2f

Documentation/hwspinlock.txt

+10 −0
Original line number Diff line number Diff line
@@ -48,6 +48,16 @@ independent, drivers. 
     ids for predefined purposes.

     Should be called from a process context (might sleep).



  int of_hwspin_lock_get_id(struct device_node *np, int index);

   - retrieve the global lock id for an OF phandle-based specific lock.

     This function provides a means for DT users of a hwspinlock module

     to get the global lock id of a specific hwspinlock, so that it can

     be requested using the normal hwspin_lock_request_specific() API.

     The function returns a lock id number on success, -EPROBE_DEFER if

     the hwspinlock device is not yet registered with the core, or other

     error values.

     Should be called from a process context (might sleep).



  int hwspin_lock_free(struct hwspinlock *hwlock);

   - free a previously-assigned hwspinlock; returns 0 on success, or an

     appropriate error code on failure (e.g. -EINVAL if the hwspinlock

drivers/hwspinlock/hwspinlock_core.c

+79 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/hwspinlock.h>

#include <linux/pm_runtime.h>

#include <linux/mutex.h>

#include <linux/of.h>



#include "hwspinlock_internal.h"
@@ -257,6 +258,84 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) 
}

EXPORT_SYMBOL_GPL(__hwspin_unlock);



/**

 * of_hwspin_lock_simple_xlate - translate hwlock_spec to return a lock id

 * @bank: the hwspinlock device bank

 * @hwlock_spec: hwlock specifier as found in the device tree

 *

 * This is a simple translation function, suitable for hwspinlock platform

 * drivers that only has a lock specifier length of 1.

 *

 * Returns a relative index of the lock within a specified bank on success,

 * or -EINVAL on invalid specifier cell count.

 */

static inline int

of_hwspin_lock_simple_xlate(const struct of_phandle_args *hwlock_spec)

{

	if (WARN_ON(hwlock_spec->args_count != 1))

		return -EINVAL;



	return hwlock_spec->args[0];

}



/**

 * of_hwspin_lock_get_id() - get lock id for an OF phandle-based specific lock

 * @np: device node from which to request the specific hwlock

 * @index: index of the hwlock in the list of values

 *

 * This function provides a means for DT users of the hwspinlock module to

 * get the global lock id of a specific hwspinlock using the phandle of the

 * hwspinlock device, so that it can be requested using the normal

 * hwspin_lock_request_specific() API.

 *

 * Returns the global lock id number on success, -EPROBE_DEFER if the hwspinlock

 * device is not yet registered, -EINVAL on invalid args specifier value or an

 * appropriate error as returned from the OF parsing of the DT client node.

 */

int of_hwspin_lock_get_id(struct device_node *np, int index)

{

	struct of_phandle_args args;

	struct hwspinlock *hwlock;

	struct radix_tree_iter iter;

	void **slot;

	int id;

	int ret;



	ret = of_parse_phandle_with_args(np, "hwlocks", "#hwlock-cells", index,

					 &args);

	if (ret)

		return ret;



	/* Find the hwspinlock device: we need its base_id */

	ret = -EPROBE_DEFER;

	rcu_read_lock();

	radix_tree_for_each_slot(slot, &hwspinlock_tree, &iter, 0) {

		hwlock = radix_tree_deref_slot(slot);

		if (unlikely(!hwlock))

			continue;



		if (hwlock->bank->dev->of_node == args.np) {

			ret = 0;

			break;

		}

	}

	rcu_read_unlock();

	if (ret < 0)

		goto out;



	id = of_hwspin_lock_simple_xlate(&args);

	if (id < 0 || id >= hwlock->bank->num_locks) {

		ret = -EINVAL;

		goto out;

	}

	id += hwlock->bank->base_id;



out:

	of_node_put(args.np);

	return ret ? ret : id;

}

EXPORT_SYMBOL_GPL(of_hwspin_lock_get_id);



static int hwspin_lock_register_single(struct hwspinlock *hwlock, int id)

{

	struct hwspinlock *tmp;

include/linux/hwspinlock.h

+7 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#define HWLOCK_IRQ	0x02	/* Disable interrupts, don't save state */



struct device;

struct device_node;

struct hwspinlock;

struct hwspinlock_device;

struct hwspinlock_ops;
@@ -66,6 +67,7 @@ int hwspin_lock_unregister(struct hwspinlock_device *bank); 
struct hwspinlock *hwspin_lock_request(void);

struct hwspinlock *hwspin_lock_request_specific(unsigned int id);

int hwspin_lock_free(struct hwspinlock *hwlock);

int of_hwspin_lock_get_id(struct device_node *np, int index);

int hwspin_lock_get_id(struct hwspinlock *hwlock);

int __hwspin_lock_timeout(struct hwspinlock *, unsigned int, int,

							unsigned long *);
@@ -120,6 +122,11 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) 
{

}



static inline int of_hwspin_lock_get_id(struct device_node *np, int index)

{

	return 0;

}



static inline int hwspin_lock_get_id(struct hwspinlock *hwlock)

{

	return 0;