hwspinlock/core: register a bank of hwspinlocks in a single API call

Hardware Spinlock devices usually contain numerous locks (known
devices today support between 32 to 256 locks).

Originally hwspinlock core required drivers to register (and later,
when needed, unregister) each lock separately.

That worked, but required hwspinlocks drivers to do a bit extra work
when they were probed/removed.

This patch changes hwspin_lock_{un}register() to allow a bank of
hwspinlocks to be {un}registered in a single invocation.

A new 'struct hwspinlock_device', which contains an array of 'struct
hwspinlock's is now being passed to the core upon registration (so
instead of wrapping each struct hwspinlock, a priv member has been added
to allow drivers to piggyback their private data with each hwspinlock).

While at it, several per-lock members were moved to be per-device:
1. struct device *dev
2. struct hwspinlock_ops *ops

In addition, now that the array of locks is handled by the core,
there's no reason to maintain a per-lock 'int id' member: the id of the
lock anyway equals to its index in the bank's array plus the bank's
base_id.
Remove this per-lock id member too, and instead use a simple pointers
arithmetic to derive it.

As a result of this change, hwspinlocks drivers are now simpler and smaller
(about %20 code reduction) and the memory footprint of the hwspinlock
framework is reduced.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h
index c246522a9551..08a2fee40659 100644
--- a/include/linux/hwspinlock.h
+++ b/include/linux/hwspinlock.h
@@ -20,12 +20,15 @@
 
 #include <linux/err.h>
 #include <linux/sched.h>
+#include <linux/device.h>
 
 /* hwspinlock mode argument */
 #define HWLOCK_IRQSTATE 0x01    /* Disable interrupts, save state */
 #define HWLOCK_IRQ      0x02    /* Disable interrupts, don't save state */
 
 struct hwspinlock;
+struct hwspinlock_device;
+struct hwspinlock_ops;
 
 /**
  * struct hwspinlock_pdata - platform data for hwspinlock drivers
@@ -57,8 +60,9 @@ struct hwspinlock_pdata {
 
 #if defined(CONFIG_HWSPINLOCK) || defined(CONFIG_HWSPINLOCK_MODULE)
 
-int hwspin_lock_register(struct hwspinlock *lock);
-struct hwspinlock *hwspin_lock_unregister(unsigned int id);
+int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev,
+                const struct hwspinlock_ops *ops, int base_id, int num_locks);
+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);