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-rw-r--r--crypto/async_tx/async_tx.c294
1 files changed, 294 insertions, 0 deletions
diff --git a/crypto/async_tx/async_tx.c b/crypto/async_tx/async_tx.c
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+++ b/crypto/async_tx/async_tx.c
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+/*
+ * core routines for the asynchronous memory transfer/transform api
+ *
+ * Copyright © 2006, Intel Corporation.
+ *
+ * Dan Williams <dan.j.williams@intel.com>
+ *
+ * with architecture considerations by:
+ * Neil Brown <neilb@suse.de>
+ * Jeff Garzik <jeff@garzik.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+#include <linux/rculist.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/async_tx.h>
+
+#ifdef CONFIG_DMA_ENGINE
+static int __init async_tx_init(void)
+{
+ async_dmaengine_get();
+
+ printk(KERN_INFO "async_tx: api initialized (async)\n");
+
+ return 0;
+}
+
+static void __exit async_tx_exit(void)
+{
+ 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
+ * @submit: transaction dependency and submission modifiers
+ * @tx_type: transaction type
+ */
+struct dma_chan *
+__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))
+ return depend_tx->chan;
+ return async_dma_find_channel(tx_type);
+}
+EXPORT_SYMBOL_GPL(__async_tx_find_channel);
+#endif
+
+
+/**
+ * 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_channel_switch(struct dma_async_tx_descriptor *depend_tx,
+ struct dma_async_tx_descriptor *tx)
+{
+ struct dma_chan *chan = depend_tx->chan;
+ struct dma_device *device = chan->device;
+ struct dma_async_tx_descriptor *intr_tx = (void *) ~0;
+
+ /* first check to see if we can still append to depend_tx */
+ txd_lock(depend_tx);
+ if (txd_parent(depend_tx) && depend_tx->chan == tx->chan) {
+ txd_chain(depend_tx, tx);
+ intr_tx = NULL;
+ }
+ txd_unlock(depend_tx);
+
+ /* attached dependency, flush the parent channel */
+ if (!intr_tx) {
+ device->device_issue_pending(chan);
+ return;
+ }
+
+ /* 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;
+ /* safe to chain outside the lock since we know we are
+ * not submitted yet
+ */
+ txd_chain(intr_tx, tx);
+
+ /* check if we need to append */
+ txd_lock(depend_tx);
+ if (txd_parent(depend_tx)) {
+ txd_chain(depend_tx, intr_tx);
+ async_tx_ack(intr_tx);
+ intr_tx = NULL;
+ }
+ txd_unlock(depend_tx);
+
+ if (intr_tx) {
+ txd_clear_parent(intr_tx);
+ 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_COMPLETE)
+ panic("%s: DMA error waiting for depend_tx\n",
+ __func__);
+ tx->tx_submit(tx);
+ }
+}
+
+
+/**
+ * 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,
+ ASYNC_TX_CHANNEL_SWITCH,
+ ASYNC_TX_DIRECT_SUBMIT,
+};
+
+void
+async_tx_submit(struct dma_chan *chan, struct dma_async_tx_descriptor *tx,
+ struct async_submit_ctl *submit)
+{
+ 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;
+
+ /* 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(async_tx_test_ack(depend_tx) || txd_next(depend_tx) ||
+ txd_parent(tx));
+
+ /* the lock prevents async_tx_run_dependencies from missing
+ * the setting of ->next when ->parent != NULL
+ */
+ txd_lock(depend_tx);
+ if (txd_parent(depend_tx)) {
+ /* 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) {
+ txd_chain(depend_tx, 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;
+ }
+ txd_unlock(depend_tx);
+
+ 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:
+ txd_clear_parent(tx);
+ tx->tx_submit(tx);
+ break;
+ }
+ } else {
+ txd_clear_parent(tx);
+ tx->tx_submit(tx);
+ }
+
+ if (submit->flags & ASYNC_TX_ACK)
+ async_tx_ack(tx);
+
+ if (depend_tx)
+ async_tx_ack(depend_tx);
+}
+EXPORT_SYMBOL_GPL(async_tx_submit);
+
+/**
+ * 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(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;
+ device = chan->device;
+
+ /* see if we can schedule an interrupt
+ * otherwise poll for completion
+ */
+ if (device && !dma_has_cap(DMA_INTERRUPT, device->cap_mask))
+ device = NULL;
+
+ tx = device ? device->device_prep_dma_interrupt(chan, 0) : NULL;
+ } else
+ tx = NULL;
+
+ if (tx) {
+ pr_debug("%s: (async)\n", __func__);
+
+ async_tx_submit(chan, tx, submit);
+ } else {
+ pr_debug("%s: (sync)\n", __func__);
+
+ /* wait for any prerequisite operations */
+ async_tx_quiesce(&submit->depend_tx);
+
+ async_tx_sync_epilog(submit);
+ }
+
+ return tx;
+}
+EXPORT_SYMBOL_GPL(async_trigger_callback);
+
+/**
+ * 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_COMPLETE)
+ panic("%s: DMA error waiting for transaction\n",
+ __func__);
+ async_tx_ack(*tx);
+ *tx = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(async_tx_quiesce);
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("Asynchronous Bulk Memory Transactions API");
+MODULE_LICENSE("GPL");