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authorSuman Anna <s-anna@ti.com>2015-03-04 20:01:14 -0600
committerOhad Ben-Cohen <ohad@wizery.com>2015-05-02 09:54:30 +0300
commitfb7737e949e31d8a71acee6bbb670f32dbd2a2c0 (patch)
tree57ba40cfa05ca8a34211f3cbd97f77625beeed0a /drivers/hwspinlock
parent0ce8cf2f31d661a27b7656e791acacb86eb58739 (diff)
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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>
Diffstat (limited to 'drivers/hwspinlock')
-rw-r--r--drivers/hwspinlock/hwspinlock_core.c79
1 files changed, 79 insertions, 0 deletions
diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c
index 461a0d739d75..52f708bcf77f 100644
--- 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 *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;