OMAPDSS: VENC: fix NULL pointer dereference in DSS2 VENC sysfs debug attr on OMAP4
[zen-stable.git] / crypto / async_tx / async_tx.c
blob842120979374c9cfc0fd6810e577a3720d2c45ff
1 /*
2 * core routines for the asynchronous memory transfer/transform api
4 * Copyright © 2006, Intel Corporation.
6 * Dan Williams <dan.j.williams@intel.com>
8 * with architecture considerations by:
9 * Neil Brown <neilb@suse.de>
10 * Jeff Garzik <jeff@garzik.org>
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms and conditions of the GNU General Public License,
14 * version 2, as published by the Free Software Foundation.
16 * This program is distributed in the hope it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19 * more details.
21 * You should have received a copy of the GNU General Public License along with
22 * this program; if not, write to the Free Software Foundation, Inc.,
23 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
26 #include <linux/rculist.h>
27 #include <linux/module.h>
28 #include <linux/kernel.h>
29 #include <linux/async_tx.h>
31 #ifdef CONFIG_DMA_ENGINE
32 static int __init async_tx_init(void)
34 async_dmaengine_get();
36 printk(KERN_INFO "async_tx: api initialized (async)\n");
38 return 0;
41 static void __exit async_tx_exit(void)
43 async_dmaengine_put();
46 module_init(async_tx_init);
47 module_exit(async_tx_exit);
49 /**
50 * __async_tx_find_channel - find a channel to carry out the operation or let
51 * the transaction execute synchronously
52 * @submit: transaction dependency and submission modifiers
53 * @tx_type: transaction type
55 struct dma_chan *
56 __async_tx_find_channel(struct async_submit_ctl *submit,
57 enum dma_transaction_type tx_type)
59 struct dma_async_tx_descriptor *depend_tx = submit->depend_tx;
61 /* see if we can keep the chain on one channel */
62 if (depend_tx &&
63 dma_has_cap(tx_type, depend_tx->chan->device->cap_mask))
64 return depend_tx->chan;
65 return async_dma_find_channel(tx_type);
67 EXPORT_SYMBOL_GPL(__async_tx_find_channel);
68 #endif
71 /**
72 * async_tx_channel_switch - queue an interrupt descriptor with a dependency
73 * pre-attached.
74 * @depend_tx: the operation that must finish before the new operation runs
75 * @tx: the new operation
77 static void
78 async_tx_channel_switch(struct dma_async_tx_descriptor *depend_tx,
79 struct dma_async_tx_descriptor *tx)
81 struct dma_chan *chan = depend_tx->chan;
82 struct dma_device *device = chan->device;
83 struct dma_async_tx_descriptor *intr_tx = (void *) ~0;
85 /* first check to see if we can still append to depend_tx */
86 txd_lock(depend_tx);
87 if (txd_parent(depend_tx) && depend_tx->chan == tx->chan) {
88 txd_chain(depend_tx, tx);
89 intr_tx = NULL;
91 txd_unlock(depend_tx);
93 /* attached dependency, flush the parent channel */
94 if (!intr_tx) {
95 device->device_issue_pending(chan);
96 return;
99 /* see if we can schedule an interrupt
100 * otherwise poll for completion
102 if (dma_has_cap(DMA_INTERRUPT, device->cap_mask))
103 intr_tx = device->device_prep_dma_interrupt(chan, 0);
104 else
105 intr_tx = NULL;
107 if (intr_tx) {
108 intr_tx->callback = NULL;
109 intr_tx->callback_param = NULL;
110 /* safe to chain outside the lock since we know we are
111 * not submitted yet
113 txd_chain(intr_tx, tx);
115 /* check if we need to append */
116 txd_lock(depend_tx);
117 if (txd_parent(depend_tx)) {
118 txd_chain(depend_tx, intr_tx);
119 async_tx_ack(intr_tx);
120 intr_tx = NULL;
122 txd_unlock(depend_tx);
124 if (intr_tx) {
125 txd_clear_parent(intr_tx);
126 intr_tx->tx_submit(intr_tx);
127 async_tx_ack(intr_tx);
129 device->device_issue_pending(chan);
130 } else {
131 if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
132 panic("%s: DMA_ERROR waiting for depend_tx\n",
133 __func__);
134 tx->tx_submit(tx);
140 * submit_disposition - flags for routing an incoming operation
141 * @ASYNC_TX_SUBMITTED: we were able to append the new operation under the lock
142 * @ASYNC_TX_CHANNEL_SWITCH: when the lock is dropped schedule a channel switch
143 * @ASYNC_TX_DIRECT_SUBMIT: when the lock is dropped submit directly
145 * while holding depend_tx->lock we must avoid submitting new operations
146 * to prevent a circular locking dependency with drivers that already
147 * hold a channel lock when calling async_tx_run_dependencies.
149 enum submit_disposition {
150 ASYNC_TX_SUBMITTED,
151 ASYNC_TX_CHANNEL_SWITCH,
152 ASYNC_TX_DIRECT_SUBMIT,
155 void
156 async_tx_submit(struct dma_chan *chan, struct dma_async_tx_descriptor *tx,
157 struct async_submit_ctl *submit)
159 struct dma_async_tx_descriptor *depend_tx = submit->depend_tx;
161 tx->callback = submit->cb_fn;
162 tx->callback_param = submit->cb_param;
164 if (depend_tx) {
165 enum submit_disposition s;
167 /* sanity check the dependency chain:
168 * 1/ if ack is already set then we cannot be sure
169 * we are referring to the correct operation
170 * 2/ dependencies are 1:1 i.e. two transactions can
171 * not depend on the same parent
173 BUG_ON(async_tx_test_ack(depend_tx) || txd_next(depend_tx) ||
174 txd_parent(tx));
176 /* the lock prevents async_tx_run_dependencies from missing
177 * the setting of ->next when ->parent != NULL
179 txd_lock(depend_tx);
180 if (txd_parent(depend_tx)) {
181 /* we have a parent so we can not submit directly
182 * if we are staying on the same channel: append
183 * else: channel switch
185 if (depend_tx->chan == chan) {
186 txd_chain(depend_tx, tx);
187 s = ASYNC_TX_SUBMITTED;
188 } else
189 s = ASYNC_TX_CHANNEL_SWITCH;
190 } else {
191 /* we do not have a parent so we may be able to submit
192 * directly if we are staying on the same channel
194 if (depend_tx->chan == chan)
195 s = ASYNC_TX_DIRECT_SUBMIT;
196 else
197 s = ASYNC_TX_CHANNEL_SWITCH;
199 txd_unlock(depend_tx);
201 switch (s) {
202 case ASYNC_TX_SUBMITTED:
203 break;
204 case ASYNC_TX_CHANNEL_SWITCH:
205 async_tx_channel_switch(depend_tx, tx);
206 break;
207 case ASYNC_TX_DIRECT_SUBMIT:
208 txd_clear_parent(tx);
209 tx->tx_submit(tx);
210 break;
212 } else {
213 txd_clear_parent(tx);
214 tx->tx_submit(tx);
217 if (submit->flags & ASYNC_TX_ACK)
218 async_tx_ack(tx);
220 if (depend_tx)
221 async_tx_ack(depend_tx);
223 EXPORT_SYMBOL_GPL(async_tx_submit);
226 * async_trigger_callback - schedules the callback function to be run
227 * @submit: submission and completion parameters
229 * honored flags: ASYNC_TX_ACK
231 * The callback is run after any dependent operations have completed.
233 struct dma_async_tx_descriptor *
234 async_trigger_callback(struct async_submit_ctl *submit)
236 struct dma_chan *chan;
237 struct dma_device *device;
238 struct dma_async_tx_descriptor *tx;
239 struct dma_async_tx_descriptor *depend_tx = submit->depend_tx;
241 if (depend_tx) {
242 chan = depend_tx->chan;
243 device = chan->device;
245 /* see if we can schedule an interrupt
246 * otherwise poll for completion
248 if (device && !dma_has_cap(DMA_INTERRUPT, device->cap_mask))
249 device = NULL;
251 tx = device ? device->device_prep_dma_interrupt(chan, 0) : NULL;
252 } else
253 tx = NULL;
255 if (tx) {
256 pr_debug("%s: (async)\n", __func__);
258 async_tx_submit(chan, tx, submit);
259 } else {
260 pr_debug("%s: (sync)\n", __func__);
262 /* wait for any prerequisite operations */
263 async_tx_quiesce(&submit->depend_tx);
265 async_tx_sync_epilog(submit);
268 return tx;
270 EXPORT_SYMBOL_GPL(async_trigger_callback);
273 * async_tx_quiesce - ensure tx is complete and freeable upon return
274 * @tx - transaction to quiesce
276 void async_tx_quiesce(struct dma_async_tx_descriptor **tx)
278 if (*tx) {
279 /* if ack is already set then we cannot be sure
280 * we are referring to the correct operation
282 BUG_ON(async_tx_test_ack(*tx));
283 if (dma_wait_for_async_tx(*tx) == DMA_ERROR)
284 panic("DMA_ERROR waiting for transaction\n");
285 async_tx_ack(*tx);
286 *tx = NULL;
289 EXPORT_SYMBOL_GPL(async_tx_quiesce);
291 MODULE_AUTHOR("Intel Corporation");
292 MODULE_DESCRIPTION("Asynchronous Bulk Memory Transactions API");
293 MODULE_LICENSE("GPL");