diff options
| -rw-r--r-- | Documentation/hwspinlock.txt | 10 | ||||
| -rw-r--r-- | drivers/hwspinlock/hwspinlock_core.c | 79 | ||||
| -rw-r--r-- | include/linux/hwspinlock.h | 7 |
3 files changed, 96 insertions, 0 deletions
diff --git a/Documentation/hwspinlock.txt b/Documentation/hwspinlock.txt index 62f7d4ea6e26..61c1ee98e59f 100644 --- 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 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; diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h index 3343298e40e8..859d673d98c8 100644 --- 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 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; |