* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
+#include <linux/rculist.h>
#include <linux/kernel.h>
#include <linux/async_tx.h>
#ifdef CONFIG_DMA_ENGINE
-static enum dma_state_client
-dma_channel_add_remove(struct dma_client *client,
- struct dma_chan *chan, enum dma_state state);
-
-static struct dma_client async_tx_dma = {
- .event_callback = dma_channel_add_remove,
- /* .cap_mask == 0 defaults to all channels */
-};
-
-/**
- * dma_cap_mask_all - enable iteration over all operation types
- */
-static dma_cap_mask_t dma_cap_mask_all;
-
-/**
- * chan_ref_percpu - tracks channel allocations per core/opertion
- */
-struct chan_ref_percpu {
- struct dma_chan_ref *ref;
-};
-
-static int channel_table_initialized;
-static struct chan_ref_percpu *channel_table[DMA_TX_TYPE_END];
-
-/**
- * async_tx_lock - protect modification of async_tx_master_list and serialize
- * rebalance operations
- */
-static spinlock_t async_tx_lock;
-
-static LIST_HEAD(async_tx_master_list);
-
-/* async_tx_issue_pending_all - start all transactions on all channels */
-void async_tx_issue_pending_all(void)
-{
- struct dma_chan_ref *ref;
-
- rcu_read_lock();
- list_for_each_entry_rcu(ref, &async_tx_master_list, node)
- ref->chan->device->device_issue_pending(ref->chan);
- rcu_read_unlock();
-}
-EXPORT_SYMBOL_GPL(async_tx_issue_pending_all);
-
-/* dma_wait_for_async_tx - spin wait for a transcation to complete
- * @tx: transaction to wait on
- */
-enum dma_status
-dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
+static int __init async_tx_init(void)
{
- enum dma_status status;
- struct dma_async_tx_descriptor *iter;
- struct dma_async_tx_descriptor *parent;
-
- if (!tx)
- return DMA_SUCCESS;
-
- /* poll through the dependency chain, return when tx is complete */
- do {
- iter = tx;
-
- /* find the root of the unsubmitted dependency chain */
- while (iter->cookie == -EBUSY) {
- parent = iter->parent;
- if (parent && parent->cookie == -EBUSY)
- iter = iter->parent;
- else
- break;
- }
-
- status = dma_sync_wait(iter->chan, iter->cookie);
- } while (status == DMA_IN_PROGRESS || (iter != tx));
+ async_dmaengine_get();
- return status;
-}
-EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
-
-/* async_tx_run_dependencies - helper routine for dma drivers to process
- * (start) dependent operations on their target channel
- * @tx: transaction with dependencies
- */
-void
-async_tx_run_dependencies(struct dma_async_tx_descriptor *tx)
-{
- struct dma_async_tx_descriptor *dep_tx, *_dep_tx;
- struct dma_device *dev;
- struct dma_chan *chan;
+ printk(KERN_INFO "async_tx: api initialized (async)\n");
- list_for_each_entry_safe(dep_tx, _dep_tx, &tx->depend_list,
- depend_node) {
- chan = dep_tx->chan;
- dev = chan->device;
- /* we can't depend on ourselves */
- BUG_ON(chan == tx->chan);
- list_del(&dep_tx->depend_node);
- tx->tx_submit(dep_tx);
-
- /* we need to poke the engine as client code does not
- * know about dependency submission events
- */
- dev->device_issue_pending(chan);
- }
+ return 0;
}
-EXPORT_SYMBOL_GPL(async_tx_run_dependencies);
-static void
-free_dma_chan_ref(struct rcu_head *rcu)
+static void __exit async_tx_exit(void)
{
- struct dma_chan_ref *ref;
- ref = container_of(rcu, struct dma_chan_ref, rcu);
- kfree(ref);
+ async_dmaengine_put();
}
-static void
-init_dma_chan_ref(struct dma_chan_ref *ref, struct dma_chan *chan)
-{
- INIT_LIST_HEAD(&ref->node);
- INIT_RCU_HEAD(&ref->rcu);
- ref->chan = chan;
- atomic_set(&ref->count, 0);
-}
+module_init(async_tx_init);
+module_exit(async_tx_exit);
/**
- * get_chan_ref_by_cap - returns the nth channel of the given capability
- * defaults to returning the channel with the desired capability and the
- * lowest reference count if the index can not be satisfied
- * @cap: capability to match
- * @index: nth channel desired, passing -1 has the effect of forcing the
- * default return value
+ * __async_tx_find_channel - find a channel to carry out the operation or let
+ * the transaction execute synchronously
+ * @submit: transaction dependency and submission modifiers
+ * @tx_type: transaction type
*/
-static struct dma_chan_ref *
-get_chan_ref_by_cap(enum dma_transaction_type cap, int index)
+struct dma_chan *
+__async_tx_find_channel(struct async_submit_ctl *submit,
+ enum dma_transaction_type tx_type)
{
- struct dma_chan_ref *ret_ref = NULL, *min_ref = NULL, *ref;
-
- rcu_read_lock();
- list_for_each_entry_rcu(ref, &async_tx_master_list, node)
- if (dma_has_cap(cap, ref->chan->device->cap_mask)) {
- if (!min_ref)
- min_ref = ref;
- else if (atomic_read(&ref->count) <
- atomic_read(&min_ref->count))
- min_ref = ref;
-
- if (index-- == 0) {
- ret_ref = ref;
- break;
- }
- }
- rcu_read_unlock();
-
- if (!ret_ref)
- ret_ref = min_ref;
-
- if (ret_ref)
- atomic_inc(&ret_ref->count);
+ struct dma_async_tx_descriptor *depend_tx = submit->depend_tx;
- return ret_ref;
+ /* see if we can keep the chain on one channel */
+ if (depend_tx &&
+ dma_has_cap(tx_type, depend_tx->chan->device->cap_mask))
+ return depend_tx->chan;
+ return async_dma_find_channel(tx_type);
}
+EXPORT_SYMBOL_GPL(__async_tx_find_channel);
+#endif
+
/**
- * async_tx_rebalance - redistribute the available channels, optimize
- * for cpu isolation in the SMP case, and opertaion isolation in the
- * uniprocessor case
+ * async_tx_channel_switch - queue an interrupt descriptor with a dependency
+ * pre-attached.
+ * @depend_tx: the operation that must finish before the new operation runs
+ * @tx: the new operation
*/
-static void async_tx_rebalance(void)
-{
- int cpu, cap, cpu_idx = 0;
- unsigned long flags;
-
- if (!channel_table_initialized)
- return;
-
- spin_lock_irqsave(&async_tx_lock, flags);
-
- /* undo the last distribution */
- for_each_dma_cap_mask(cap, dma_cap_mask_all)
- for_each_possible_cpu(cpu) {
- struct dma_chan_ref *ref =
- per_cpu_ptr(channel_table[cap], cpu)->ref;
- if (ref) {
- atomic_set(&ref->count, 0);
- per_cpu_ptr(channel_table[cap], cpu)->ref =
- NULL;
- }
- }
-
- for_each_dma_cap_mask(cap, dma_cap_mask_all)
- for_each_online_cpu(cpu) {
- struct dma_chan_ref *new;
- if (NR_CPUS > 1)
- new = get_chan_ref_by_cap(cap, cpu_idx++);
- else
- new = get_chan_ref_by_cap(cap, -1);
-
- per_cpu_ptr(channel_table[cap], cpu)->ref = new;
- }
-
- spin_unlock_irqrestore(&async_tx_lock, flags);
-}
-
-static enum dma_state_client
-dma_channel_add_remove(struct dma_client *client,
- struct dma_chan *chan, enum dma_state state)
+static void
+async_tx_channel_switch(struct dma_async_tx_descriptor *depend_tx,
+ struct dma_async_tx_descriptor *tx)
{
- unsigned long found, flags;
- struct dma_chan_ref *master_ref, *ref;
- enum dma_state_client ack = DMA_DUP; /* default: take no action */
-
- switch (state) {
- case DMA_RESOURCE_AVAILABLE:
- found = 0;
- rcu_read_lock();
- list_for_each_entry_rcu(ref, &async_tx_master_list, node)
- if (ref->chan == chan) {
- found = 1;
- break;
- }
- rcu_read_unlock();
-
- pr_debug("async_tx: dma resource available [%s]\n",
- found ? "old" : "new");
-
- if (!found)
- ack = DMA_ACK;
- else
- break;
+ struct dma_chan *chan = depend_tx->chan;
+ struct dma_device *device = chan->device;
+ struct dma_async_tx_descriptor *intr_tx = (void *) ~0;
- /* add the channel to the generic management list */
- master_ref = kmalloc(sizeof(*master_ref), GFP_KERNEL);
- if (master_ref) {
- /* keep a reference until async_tx is unloaded */
- dma_chan_get(chan);
- init_dma_chan_ref(master_ref, chan);
- spin_lock_irqsave(&async_tx_lock, flags);
- list_add_tail_rcu(&master_ref->node,
- &async_tx_master_list);
- spin_unlock_irqrestore(&async_tx_lock,
- flags);
- } else {
- printk(KERN_WARNING "async_tx: unable to create"
- " new master entry in response to"
- " a DMA_RESOURCE_ADDED event"
- " (-ENOMEM)\n");
- return 0;
- }
-
- async_tx_rebalance();
- break;
- case DMA_RESOURCE_REMOVED:
- found = 0;
- spin_lock_irqsave(&async_tx_lock, flags);
- list_for_each_entry_rcu(ref, &async_tx_master_list, node)
- if (ref->chan == chan) {
- /* permit backing devices to go away */
- dma_chan_put(ref->chan);
- list_del_rcu(&ref->node);
- call_rcu(&ref->rcu, free_dma_chan_ref);
- found = 1;
- break;
- }
- spin_unlock_irqrestore(&async_tx_lock, flags);
-
- pr_debug("async_tx: dma resource removed [%s]\n",
- found ? "ours" : "not ours");
-
- if (found)
- ack = DMA_ACK;
- else
- break;
+ #ifdef CONFIG_ASYNC_TX_DISABLE_CHANNEL_SWITCH
+ BUG();
+ #endif
- async_tx_rebalance();
- break;
- case DMA_RESOURCE_SUSPEND:
- case DMA_RESOURCE_RESUME:
- printk(KERN_WARNING "async_tx: does not support dma channel"
- " suspend/resume\n");
- break;
- default:
- BUG();
+ /* first check to see if we can still append to depend_tx */
+ spin_lock_bh(&depend_tx->lock);
+ if (depend_tx->parent && depend_tx->chan == tx->chan) {
+ tx->parent = depend_tx;
+ depend_tx->next = tx;
+ intr_tx = NULL;
}
+ spin_unlock_bh(&depend_tx->lock);
- return ack;
-}
-
-static int __init
-async_tx_init(void)
-{
- enum dma_transaction_type cap;
-
- spin_lock_init(&async_tx_lock);
- bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
-
- /* an interrupt will never be an explicit operation type.
- * clearing this bit prevents allocation to a slot in 'channel_table'
- */
- clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
-
- for_each_dma_cap_mask(cap, dma_cap_mask_all) {
- channel_table[cap] = alloc_percpu(struct chan_ref_percpu);
- if (!channel_table[cap])
- goto err;
+ /* attached dependency, flush the parent channel */
+ if (!intr_tx) {
+ device->device_issue_pending(chan);
+ return;
}
- channel_table_initialized = 1;
- dma_async_client_register(&async_tx_dma);
- dma_async_client_chan_request(&async_tx_dma);
-
- printk(KERN_INFO "async_tx: api initialized (async)\n");
-
- return 0;
-err:
- printk(KERN_ERR "async_tx: initialization failure\n");
+ /* see if we can schedule an interrupt
+ * otherwise poll for completion
+ */
+ if (dma_has_cap(DMA_INTERRUPT, device->cap_mask))
+ intr_tx = device->device_prep_dma_interrupt(chan, 0);
+ else
+ intr_tx = NULL;
+
+ if (intr_tx) {
+ intr_tx->callback = NULL;
+ intr_tx->callback_param = NULL;
+ tx->parent = intr_tx;
+ /* safe to set ->next outside the lock since we know we are
+ * not submitted yet
+ */
+ intr_tx->next = tx;
- while (--cap >= 0)
- free_percpu(channel_table[cap]);
+ /* check if we need to append */
+ spin_lock_bh(&depend_tx->lock);
+ if (depend_tx->parent) {
+ intr_tx->parent = depend_tx;
+ depend_tx->next = intr_tx;
+ async_tx_ack(intr_tx);
+ intr_tx = NULL;
+ }
+ spin_unlock_bh(&depend_tx->lock);
- return 1;
+ if (intr_tx) {
+ intr_tx->parent = NULL;
+ intr_tx->tx_submit(intr_tx);
+ async_tx_ack(intr_tx);
+ }
+ device->device_issue_pending(chan);
+ } else {
+ if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
+ panic("%s: DMA_ERROR waiting for depend_tx\n",
+ __func__);
+ tx->tx_submit(tx);
+ }
}
-static void __exit async_tx_exit(void)
-{
- enum dma_transaction_type cap;
-
- channel_table_initialized = 0;
-
- for_each_dma_cap_mask(cap, dma_cap_mask_all)
- if (channel_table[cap])
- free_percpu(channel_table[cap]);
-
- dma_async_client_unregister(&async_tx_dma);
-}
/**
- * async_tx_find_channel - find a channel to carry out the operation or let
- * the transaction execute synchronously
- * @depend_tx: transaction dependency
- * @tx_type: transaction type
+ * submit_disposition - flags for routing an incoming operation
+ * @ASYNC_TX_SUBMITTED: we were able to append the new operation under the lock
+ * @ASYNC_TX_CHANNEL_SWITCH: when the lock is dropped schedule a channel switch
+ * @ASYNC_TX_DIRECT_SUBMIT: when the lock is dropped submit directly
+ *
+ * while holding depend_tx->lock we must avoid submitting new operations
+ * to prevent a circular locking dependency with drivers that already
+ * hold a channel lock when calling async_tx_run_dependencies.
*/
-struct dma_chan *
-async_tx_find_channel(struct dma_async_tx_descriptor *depend_tx,
- enum dma_transaction_type tx_type)
-{
- /* see if we can keep the chain on one channel */
- if (depend_tx &&
- dma_has_cap(tx_type, depend_tx->chan->device->cap_mask))
- return depend_tx->chan;
- else if (likely(channel_table_initialized)) {
- struct dma_chan_ref *ref;
- int cpu = get_cpu();
- ref = per_cpu_ptr(channel_table[tx_type], cpu)->ref;
- put_cpu();
- return ref ? ref->chan : NULL;
- } else
- return NULL;
-}
-EXPORT_SYMBOL_GPL(async_tx_find_channel);
-#else
-static int __init async_tx_init(void)
-{
- printk(KERN_INFO "async_tx: api initialized (sync-only)\n");
- return 0;
-}
-
-static void __exit async_tx_exit(void)
-{
- do { } while (0);
-}
-#endif
+enum submit_disposition {
+ ASYNC_TX_SUBMITTED,
+ ASYNC_TX_CHANNEL_SWITCH,
+ ASYNC_TX_DIRECT_SUBMIT,
+};
void
async_tx_submit(struct dma_chan *chan, struct dma_async_tx_descriptor *tx,
- enum async_tx_flags flags, struct dma_async_tx_descriptor *depend_tx,
- dma_async_tx_callback cb_fn, void *cb_param)
+ struct async_submit_ctl *submit)
{
- tx->callback = cb_fn;
- tx->callback_param = cb_param;
+ struct dma_async_tx_descriptor *depend_tx = submit->depend_tx;
- /* set this new tx to run after depend_tx if:
- * 1/ a dependency exists (depend_tx is !NULL)
- * 2/ the tx can not be submitted to the current channel
- */
- if (depend_tx && depend_tx->chan != chan) {
- /* if ack is already set then we cannot be sure
+ tx->callback = submit->cb_fn;
+ tx->callback_param = submit->cb_param;
+
+ if (depend_tx) {
+ enum submit_disposition s;
+
+ /* sanity check the dependency chain:
+ * 1/ if ack is already set then we cannot be sure
* we are referring to the correct operation
+ * 2/ dependencies are 1:1 i.e. two transactions can
+ * not depend on the same parent
*/
- BUG_ON(depend_tx->ack);
+ BUG_ON(async_tx_test_ack(depend_tx) || depend_tx->next ||
+ tx->parent);
- tx->parent = depend_tx;
+ /* the lock prevents async_tx_run_dependencies from missing
+ * the setting of ->next when ->parent != NULL
+ */
spin_lock_bh(&depend_tx->lock);
- list_add_tail(&tx->depend_node, &depend_tx->depend_list);
- if (depend_tx->cookie == 0) {
- struct dma_chan *dep_chan = depend_tx->chan;
- struct dma_device *dep_dev = dep_chan->device;
- dep_dev->device_dependency_added(dep_chan);
+ if (depend_tx->parent) {
+ /* we have a parent so we can not submit directly
+ * if we are staying on the same channel: append
+ * else: channel switch
+ */
+ if (depend_tx->chan == chan) {
+ tx->parent = depend_tx;
+ depend_tx->next = tx;
+ s = ASYNC_TX_SUBMITTED;
+ } else
+ s = ASYNC_TX_CHANNEL_SWITCH;
+ } else {
+ /* we do not have a parent so we may be able to submit
+ * directly if we are staying on the same channel
+ */
+ if (depend_tx->chan == chan)
+ s = ASYNC_TX_DIRECT_SUBMIT;
+ else
+ s = ASYNC_TX_CHANNEL_SWITCH;
}
spin_unlock_bh(&depend_tx->lock);
- /* schedule an interrupt to trigger the channel switch */
- async_trigger_callback(ASYNC_TX_ACK, depend_tx, NULL, NULL);
+ switch (s) {
+ case ASYNC_TX_SUBMITTED:
+ break;
+ case ASYNC_TX_CHANNEL_SWITCH:
+ async_tx_channel_switch(depend_tx, tx);
+ break;
+ case ASYNC_TX_DIRECT_SUBMIT:
+ tx->parent = NULL;
+ tx->tx_submit(tx);
+ break;
+ }
} else {
tx->parent = NULL;
tx->tx_submit(tx);
}
- if (flags & ASYNC_TX_ACK)
+ if (submit->flags & ASYNC_TX_ACK)
async_tx_ack(tx);
- if (depend_tx && (flags & ASYNC_TX_DEP_ACK))
+ if (depend_tx)
async_tx_ack(depend_tx);
}
EXPORT_SYMBOL_GPL(async_tx_submit);
/**
- * async_trigger_callback - schedules the callback function to be run after
- * any dependent operations have been completed.
- * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
- * @depend_tx: 'callback' requires the completion of this transaction
- * @cb_fn: function to call after depend_tx completes
- * @cb_param: parameter to pass to the callback routine
+ * async_trigger_callback - schedules the callback function to be run
+ * @submit: submission and completion parameters
+ *
+ * honored flags: ASYNC_TX_ACK
+ *
+ * The callback is run after any dependent operations have completed.
*/
struct dma_async_tx_descriptor *
-async_trigger_callback(enum async_tx_flags flags,
- struct dma_async_tx_descriptor *depend_tx,
- dma_async_tx_callback cb_fn, void *cb_param)
+async_trigger_callback(struct async_submit_ctl *submit)
{
struct dma_chan *chan;
struct dma_device *device;
struct dma_async_tx_descriptor *tx;
+ struct dma_async_tx_descriptor *depend_tx = submit->depend_tx;
if (depend_tx) {
chan = depend_tx->chan;
if (device && !dma_has_cap(DMA_INTERRUPT, device->cap_mask))
device = NULL;
- tx = device ? device->device_prep_dma_interrupt(chan) : NULL;
+ tx = device ? device->device_prep_dma_interrupt(chan, 0) : NULL;
} else
tx = NULL;
if (tx) {
- pr_debug("%s: (async)\n", __FUNCTION__);
+ pr_debug("%s: (async)\n", __func__);
- async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
+ async_tx_submit(chan, tx, submit);
} else {
- pr_debug("%s: (sync)\n", __FUNCTION__);
+ pr_debug("%s: (sync)\n", __func__);
/* wait for any prerequisite operations */
- if (depend_tx) {
- /* if ack is already set then we cannot be sure
- * we are referring to the correct operation
- */
- BUG_ON(depend_tx->ack);
- if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
- panic("%s: DMA_ERROR waiting for depend_tx\n",
- __FUNCTION__);
- }
+ async_tx_quiesce(&submit->depend_tx);
- async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
+ async_tx_sync_epilog(submit);
}
return tx;
}
EXPORT_SYMBOL_GPL(async_trigger_callback);
-module_init(async_tx_init);
-module_exit(async_tx_exit);
+/**
+ * async_tx_quiesce - ensure tx is complete and freeable upon return
+ * @tx - transaction to quiesce
+ */
+void async_tx_quiesce(struct dma_async_tx_descriptor **tx)
+{
+ if (*tx) {
+ /* if ack is already set then we cannot be sure
+ * we are referring to the correct operation
+ */
+ BUG_ON(async_tx_test_ack(*tx));
+ if (dma_wait_for_async_tx(*tx) == DMA_ERROR)
+ panic("DMA_ERROR waiting for transaction\n");
+ async_tx_ack(*tx);
+ *tx = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(async_tx_quiesce);
MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("Asynchronous Bulk Memory Transactions API");
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff