#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)
-{
- 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 */
- do {
- parent = iter->parent;
- if (!parent)
- break;
- else
- iter = parent;
- } while (parent);
-
- /* there is a small window for ->parent == NULL and
- * ->cookie == -EBUSY
- */
- while (iter->cookie == -EBUSY)
- cpu_relax();
-
- status = dma_sync_wait(iter->chan, iter->cookie);
- } while (status == DMA_IN_PROGRESS || (iter != tx));
-
- 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->next;
- struct dma_async_tx_descriptor *dep_next;
- struct dma_chan *chan;
-
- if (!dep)
- return;
-
- chan = dep->chan;
-
- /* keep submitting up until a channel switch is detected
- * in that case we will be called again as a result of
- * processing the interrupt from async_tx_channel_switch
- */
- for (; dep; dep = dep_next) {
- spin_lock_bh(&dep->lock);
- dep->parent = NULL;
- dep_next = dep->next;
- if (dep_next && dep_next->chan == chan)
- dep->next = NULL; /* ->next will be submitted */
- else
- dep_next = NULL; /* submit current dep and terminate */
- spin_unlock_bh(&dep->lock);
-
- dep->tx_submit(dep);
- }
-
- chan->device->device_issue_pending(chan);
-}
-EXPORT_SYMBOL_GPL(async_tx_run_dependencies);
-
-static void
-free_dma_chan_ref(struct rcu_head *rcu)
-{
- struct dma_chan_ref *ref;
- ref = container_of(rcu, struct dma_chan_ref, rcu);
- kfree(ref);
-}
-
-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);
-}
-
-/**
- * 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
- */
-static struct dma_chan_ref *
-get_chan_ref_by_cap(enum dma_transaction_type cap, int index)
-{
- 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);
-
- return ret_ref;
-}
-
-/**
- * async_tx_rebalance - redistribute the available channels, optimize
- * for cpu isolation in the SMP case, and opertaion isolation in the
- * uniprocessor case
- */
-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)
-{
- 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;
-
- /* 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(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;
-
- 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();
- }
-
- return ack;
-}
-
-static int __init
-async_tx_init(void)
+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;
- }
-
- channel_table_initialized = 1;
- dma_async_client_register(&async_tx_dma);
- dma_async_client_chan_request(&async_tx_dma);
+ async_dmaengine_get();
printk(KERN_INFO "async_tx: api initialized (async)\n");
return 0;
-err:
- printk(KERN_ERR "async_tx: initialization failure\n");
-
- while (--cap >= 0)
- free_percpu(channel_table[cap]);
-
- return 1;
}
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_dmaengine_put();
}
+module_init(async_tx_init);
+module_exit(async_tx_exit);
+
/**
* __async_tx_find_channel - find a channel to carry out the operation or let
* the transaction execute synchronously
- * @depend_tx: transaction dependency
+ * @submit: transaction dependency and submission modifiers
* @tx_type: transaction type
*/
struct dma_chan *
-__async_tx_find_channel(struct dma_async_tx_descriptor *depend_tx,
- enum dma_transaction_type tx_type)
+__async_tx_find_channel(struct async_submit_ctl *submit,
+ enum dma_transaction_type tx_type)
{
+ struct dma_async_tx_descriptor *depend_tx = submit->depend_tx;
+
/* see if we can keep the chain on one channel */
if (depend_tx &&
- dma_has_cap(tx_type, depend_tx->chan->device->cap_mask))
+ 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;
+ return async_dma_find_channel(tx_type);
}
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
async_tx_channel_switch(struct dma_async_tx_descriptor *depend_tx,
struct dma_async_tx_descriptor *tx)
{
- struct dma_chan *chan;
- struct dma_device *device;
+ struct dma_chan *chan = depend_tx->chan;
+ struct dma_device *device = chan->device;
struct dma_async_tx_descriptor *intr_tx = (void *) ~0;
+ #ifdef CONFIG_ASYNC_TX_DISABLE_CHANNEL_SWITCH
+ BUG();
+ #endif
+
/* 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) {
}
spin_unlock_bh(&depend_tx->lock);
- if (!intr_tx)
+ /* attached dependency, flush the parent channel */
+ if (!intr_tx) {
+ device->device_issue_pending(chan);
return;
-
- chan = depend_tx->chan;
- device = chan->device;
+ }
/* see if we can schedule an interrupt
* otherwise poll for completion
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",
/**
- * submit_disposition - 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.
+ * 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.
*/
enum submit_disposition {
ASYNC_TX_SUBMITTED,
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;
+
+ tx->callback = submit->cb_fn;
+ tx->callback_param = submit->cb_param;
if (depend_tx) {
enum submit_disposition s;
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 (tx) {
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", __func__);
/* wait for any prerequisite operations */
- async_tx_quiesce(&depend_tx);
+ async_tx_quiesce(&submit->depend_tx);
- async_tx_sync_epilog(cb_fn, cb_param);
+ async_tx_sync_epilog(submit);
}
return tx;
}
EXPORT_SYMBOL_GPL(async_tx_quiesce);
-module_init(async_tx_init);
-module_exit(async_tx_exit);
-
MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("Asynchronous Bulk Memory Transactions API");
MODULE_LICENSE("GPL");
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