diff options
Diffstat (limited to 'include/linux/hwspinlock.h')
| -rw-r--r-- | include/linux/hwspinlock.h | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h index 8390efc457eb..f85cef5452f2 100644 --- a/include/linux/hwspinlock.h +++ b/include/linux/hwspinlock.h @@ -27,6 +27,34 @@ struct hwspinlock; +/** + * struct hwspinlock_pdata - platform data for hwspinlock drivers + * @base_id: base id for this hwspinlock device + * + * hwspinlock devices provide system-wide hardware locks that are used + * by remote processors that have no other way to achieve synchronization. + * + * To achieve that, each physical lock must have a system-wide id number + * that is agreed upon, otherwise remote processors can't possibly assume + * they're using the same hardware lock. + * + * Usually boards have a single hwspinlock device, which provides several + * hwspinlocks, and in this case, they can be trivially numbered 0 to + * (num-of-locks - 1). + * + * In case boards have several hwspinlocks devices, a different base id + * should be used for each hwspinlock device (they can't all use 0 as + * a starting id!). + * + * This platform data structure should be used to provide the base id + * for each device (which is trivially 0 when only a single hwspinlock + * device exists). It can be shared between different platforms, hence + * its location. + */ +struct hwspinlock_pdata { + int base_id; +}; + #if defined(CONFIG_HWSPINLOCK) || defined(CONFIG_HWSPINLOCK_MODULE) int hwspin_lock_register(struct hwspinlock *lock); |