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From fb7737e949e31d8a71acee6bbb670f32dbd2a2c0 Mon Sep 17 00:00:00 2001
From: Suman Anna <s-anna@ti.com>
Date: Wed, 4 Mar 2015 20:01:14 -0600
Subject: [PATCH] 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: Suman Anna <s-anna@ti.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
[small comment clarification]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
---
Documentation/hwspinlock.txt | 10 +++++
drivers/hwspinlock/hwspinlock_core.c | 79 ++++++++++++++++++++++++++++++++++++
include/linux/hwspinlock.h | 7 ++++
3 files changed, 96 insertions(+)
--- a/Documentation/hwspinlock.txt
+++ b/Documentation/hwspinlock.txt
@@ -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
--- a/drivers/hwspinlock/hwspinlock_core.c
+++ b/drivers/hwspinlock/hwspinlock_core.c
@@ -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 *
}
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;
--- a/include/linux/hwspinlock.h
+++ b/include/linux/hwspinlock.h
@@ -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 hwspin
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 *
{
}
+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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