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

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
......@@ -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
......
......@@ -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;
......
......@@ -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;
......
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