From e467b6421435f467e274d4f25d62900e1e0e4286 Mon Sep 17 00:00:00 2001 From: Ohad Ben-Cohen Date: Mon, 5 Sep 2011 16:42:36 +0300 Subject: hwspinlock/core: simplify 'owner' handling Use struct device_driver's owner member instead of asking drivers to explicitly pass the owner again. This simplifies drivers and also save some memory, since there's no point now in maintaining a separate owner pointer per hwspinlock. Signed-off-by: Ohad Ben-Cohen --- Documentation/hwspinlock.txt | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/hwspinlock.txt b/Documentation/hwspinlock.txt index 7dcd1a4e726c..bbaa4649b637 100644 --- a/Documentation/hwspinlock.txt +++ b/Documentation/hwspinlock.txt @@ -256,18 +256,16 @@ underlying hwspinlock implementation using the hwspin_lock_register() API. * @ops: vendor-specific hwspinlock handlers * @id: a global, unique, system-wide, index of the lock. * @lock: initialized and used by hwspinlock core - * @owner: underlying implementation module, used to maintain module ref count */ struct hwspinlock { struct device *dev; const struct hwspinlock_ops *ops; int id; spinlock_t lock; - struct module *owner; }; -The underlying implementation is responsible to assign the dev, ops, id and -owner members. The lock member, OTOH, is initialized and used by the hwspinlock +The underlying implementation is responsible to assign the dev, ops and id +members. The lock member, OTOH, is initialized and used by the hwspinlock core. 6. Implementation callbacks -- cgit v1.2.3 From 93b465c2e186d96fb90012ba0f9372eb9952e732 Mon Sep 17 00:00:00 2001 From: Juan Gutierrez Date: Tue, 6 Sep 2011 09:30:16 +0300 Subject: hwspinlock/core: use a mutex to protect the radix tree Since we're using non-atomic radix tree allocations, we should be protecting the tree using a mutex and not a spinlock. Non-atomic allocations and process context locking is good enough, as the tree is manipulated only when locks are registered/ unregistered/requested/freed. The locks themselves are still protected by spinlocks of course, and mutexes are not involved in the locking/unlocking paths. Cc: Signed-off-by: Juan Gutierrez [ohad@wizery.com: rewrite the commit log, #include mutex.h, add minor commentary] [ohad@wizery.com: update register/unregister parts in hwspinlock.txt] Signed-off-by: Ohad Ben-Cohen --- Documentation/hwspinlock.txt | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) (limited to 'Documentation') diff --git a/Documentation/hwspinlock.txt b/Documentation/hwspinlock.txt index bbaa4649b637..9171f9120143 100644 --- a/Documentation/hwspinlock.txt +++ b/Documentation/hwspinlock.txt @@ -39,23 +39,20 @@ independent, drivers. in case an unused hwspinlock isn't available. Users of this API will usually want to communicate the lock's id to the remote core before it can be used to achieve synchronization. - Can be called from an atomic context (this function will not sleep) but - not from within interrupt context. + Should be called from a process context (might sleep). struct hwspinlock *hwspin_lock_request_specific(unsigned int id); - assign a specific hwspinlock id and return its address, or NULL if that hwspinlock is already in use. Usually board code will be calling this function in order to reserve specific hwspinlock ids for predefined purposes. - Can be called from an atomic context (this function will not sleep) but - not from within interrupt context. + 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 is already free). - Can be called from an atomic context (this function will not sleep) but - not from within interrupt context. + Should be called from a process context (might sleep). int hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int timeout); - lock a previously-assigned hwspinlock with a timeout limit (specified in @@ -232,15 +229,14 @@ int hwspinlock_example2(void) int hwspin_lock_register(struct hwspinlock *hwlock); - to be called from the underlying platform-specific implementation, in - order to register a new hwspinlock instance. Can be called from an atomic - context (this function will not sleep) but not from within interrupt - context. Returns 0 on success, or appropriate error code on failure. + order to register a new hwspinlock instance. Should be called from + a process context (this function might sleep). + Returns 0 on success, or appropriate error code on failure. struct hwspinlock *hwspin_lock_unregister(unsigned int id); - to be called from the underlying vendor-specific implementation, in order to unregister an existing (and unused) hwspinlock instance. - Can be called from an atomic context (will not sleep) but not from - within interrupt context. + Should be called from a process context (this function might sleep). Returns the address of hwspinlock on success, or NULL on error (e.g. if the hwspinlock is sill in use). -- cgit v1.2.3 From 300bab9770e2bd10262bcc78e7249fdce2c74b38 Mon Sep 17 00:00:00 2001 From: Ohad Ben-Cohen Date: Tue, 6 Sep 2011 15:39:21 +0300 Subject: 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 --- Documentation/hwspinlock.txt | 58 +++++++++++++++++++++++++++++--------------- 1 file changed, 39 insertions(+), 19 deletions(-) (limited to 'Documentation') diff --git a/Documentation/hwspinlock.txt b/Documentation/hwspinlock.txt index 9171f9120143..a903ee5e9776 100644 --- a/Documentation/hwspinlock.txt +++ b/Documentation/hwspinlock.txt @@ -227,42 +227,62 @@ int hwspinlock_example2(void) 4. API for implementors - int hwspin_lock_register(struct hwspinlock *hwlock); + int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev, + const struct hwspinlock_ops *ops, int base_id, int num_locks); - to be called from the underlying platform-specific implementation, in - order to register a new hwspinlock instance. Should be called from - a process context (this function might sleep). + order to register a new hwspinlock device (which is usually a bank of + numerous locks). Should be called from a process context (this function + might sleep). Returns 0 on success, or appropriate error code on failure. - struct hwspinlock *hwspin_lock_unregister(unsigned int id); + int hwspin_lock_unregister(struct hwspinlock_device *bank); - to be called from the underlying vendor-specific implementation, in order - to unregister an existing (and unused) hwspinlock instance. + to unregister an hwspinlock device (which is usually a bank of numerous + locks). Should be called from a process context (this function might sleep). Returns the address of hwspinlock on success, or NULL on error (e.g. if the hwspinlock is sill in use). -5. struct hwspinlock +5. Important structs -This struct represents an hwspinlock instance. It is registered by the -underlying hwspinlock implementation using the hwspin_lock_register() API. +struct hwspinlock_device is a device which usually contains a bank +of hardware locks. It is registered by the underlying hwspinlock +implementation using the hwspin_lock_register() API. /** - * struct hwspinlock - vendor-specific hwspinlock implementation - * - * @dev: underlying device, will be used with runtime PM api - * @ops: vendor-specific hwspinlock handlers - * @id: a global, unique, system-wide, index of the lock. - * @lock: initialized and used by hwspinlock core + * struct hwspinlock_device - a device which usually spans numerous hwspinlocks + * @dev: underlying device, will be used to invoke runtime PM api + * @ops: platform-specific hwspinlock handlers + * @base_id: id index of the first lock in this device + * @num_locks: number of locks in this device + * @lock: dynamically allocated array of 'struct hwspinlock' */ -struct hwspinlock { +struct hwspinlock_device { struct device *dev; const struct hwspinlock_ops *ops; - int id; + int base_id; + int num_locks; + struct hwspinlock lock[0]; +}; + +struct hwspinlock_device contains an array of hwspinlock structs, each +of which represents a single hardware lock: + +/** + * struct hwspinlock - this struct represents a single hwspinlock instance + * @bank: the hwspinlock_device structure which owns this lock + * @lock: initialized and used by hwspinlock core + * @priv: private data, owned by the underlying platform-specific hwspinlock drv + */ +struct hwspinlock { + struct hwspinlock_device *bank; spinlock_t lock; + void *priv; }; -The underlying implementation is responsible to assign the dev, ops and id -members. The lock member, OTOH, is initialized and used by the hwspinlock -core. +When registering a bank of locks, the hwspinlock driver only needs to +set the priv members of the locks. The rest of the members are set and +initialized by the hwspinlock core itself. 6. Implementation callbacks -- cgit v1.2.3