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authorChris Leech <christopher.leech@intel.com>2006-05-23 20:18:44 -0400
committerDavid S. Miller <davem@sunset.davemloft.net>2006-06-18 00:18:43 -0400
commitc13c8260da3155f2cefb63b0d1b7dcdcb405c644 (patch)
treeecfe02fa44a423a948f5fb5ad76497da2bb7a402 /include/linux/dmaengine.h
parent427abfa28afedffadfca9dd8b067eb6d36bac53f (diff)
[I/OAT]: DMA memcpy subsystem
Provides an API for offloading memory copies to DMA devices Signed-off-by: Chris Leech <christopher.leech@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/dmaengine.h')
-rw-r--r--include/linux/dmaengine.h337
1 files changed, 337 insertions, 0 deletions
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
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1/*
2 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the Free
6 * Software Foundation; either version 2 of the License, or (at your option)
7 * any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 *
14 * You should have received a copy of the GNU General Public License along with
15 * this program; if not, write to the Free Software Foundation, Inc., 59
16 * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * The full GNU General Public License is included in this distribution in the
19 * file called COPYING.
20 */
21#ifndef DMAENGINE_H
22#define DMAENGINE_H
23#include <linux/config.h>
24#ifdef CONFIG_DMA_ENGINE
25
26#include <linux/device.h>
27#include <linux/uio.h>
28#include <linux/kref.h>
29#include <linux/completion.h>
30#include <linux/rcupdate.h>
31
32/**
33 * enum dma_event - resource PNP/power managment events
34 * @DMA_RESOURCE_SUSPEND: DMA device going into low power state
35 * @DMA_RESOURCE_RESUME: DMA device returning to full power
36 * @DMA_RESOURCE_ADDED: DMA device added to the system
37 * @DMA_RESOURCE_REMOVED: DMA device removed from the system
38 */
39enum dma_event {
40 DMA_RESOURCE_SUSPEND,
41 DMA_RESOURCE_RESUME,
42 DMA_RESOURCE_ADDED,
43 DMA_RESOURCE_REMOVED,
44};
45
46/**
47 * typedef dma_cookie_t
48 *
49 * if dma_cookie_t is >0 it's a DMA request cookie, <0 it's an error code
50 */
51typedef s32 dma_cookie_t;
52
53#define dma_submit_error(cookie) ((cookie) < 0 ? 1 : 0)
54
55/**
56 * enum dma_status - DMA transaction status
57 * @DMA_SUCCESS: transaction completed successfully
58 * @DMA_IN_PROGRESS: transaction not yet processed
59 * @DMA_ERROR: transaction failed
60 */
61enum dma_status {
62 DMA_SUCCESS,
63 DMA_IN_PROGRESS,
64 DMA_ERROR,
65};
66
67/**
68 * struct dma_chan_percpu - the per-CPU part of struct dma_chan
69 * @refcount: local_t used for open-coded "bigref" counting
70 * @memcpy_count: transaction counter
71 * @bytes_transferred: byte counter
72 */
73
74struct dma_chan_percpu {
75 local_t refcount;
76 /* stats */
77 unsigned long memcpy_count;
78 unsigned long bytes_transferred;
79};
80
81/**
82 * struct dma_chan - devices supply DMA channels, clients use them
83 * @client: ptr to the client user of this chan, will be NULL when unused
84 * @device: ptr to the dma device who supplies this channel, always !NULL
85 * @cookie: last cookie value returned to client
86 * @chan_id:
87 * @class_dev:
88 * @refcount: kref, used in "bigref" slow-mode
89 * @slow_ref:
90 * @rcu:
91 * @client_node: used to add this to the client chan list
92 * @device_node: used to add this to the device chan list
93 * @local: per-cpu pointer to a struct dma_chan_percpu
94 */
95struct dma_chan {
96 struct dma_client *client;
97 struct dma_device *device;
98 dma_cookie_t cookie;
99
100 /* sysfs */
101 int chan_id;
102 struct class_device class_dev;
103
104 struct kref refcount;
105 int slow_ref;
106 struct rcu_head rcu;
107
108 struct list_head client_node;
109 struct list_head device_node;
110 struct dma_chan_percpu *local;
111};
112
113void dma_chan_cleanup(struct kref *kref);
114
115static inline void dma_chan_get(struct dma_chan *chan)
116{
117 if (unlikely(chan->slow_ref))
118 kref_get(&chan->refcount);
119 else {
120 local_inc(&(per_cpu_ptr(chan->local, get_cpu())->refcount));
121 put_cpu();
122 }
123}
124
125static inline void dma_chan_put(struct dma_chan *chan)
126{
127 if (unlikely(chan->slow_ref))
128 kref_put(&chan->refcount, dma_chan_cleanup);
129 else {
130 local_dec(&(per_cpu_ptr(chan->local, get_cpu())->refcount));
131 put_cpu();
132 }
133}
134
135/*
136 * typedef dma_event_callback - function pointer to a DMA event callback
137 */
138typedef void (*dma_event_callback) (struct dma_client *client,
139 struct dma_chan *chan, enum dma_event event);
140
141/**
142 * struct dma_client - info on the entity making use of DMA services
143 * @event_callback: func ptr to call when something happens
144 * @chan_count: number of chans allocated
145 * @chans_desired: number of chans requested. Can be +/- chan_count
146 * @lock: protects access to the channels list
147 * @channels: the list of DMA channels allocated
148 * @global_node: list_head for global dma_client_list
149 */
150struct dma_client {
151 dma_event_callback event_callback;
152 unsigned int chan_count;
153 unsigned int chans_desired;
154
155 spinlock_t lock;
156 struct list_head channels;
157 struct list_head global_node;
158};
159
160/**
161 * struct dma_device - info on the entity supplying DMA services
162 * @chancnt: how many DMA channels are supported
163 * @channels: the list of struct dma_chan
164 * @global_node: list_head for global dma_device_list
165 * @refcount:
166 * @done:
167 * @dev_id:
168 * Other func ptrs: used to make use of this device's capabilities
169 */
170struct dma_device {
171
172 unsigned int chancnt;
173 struct list_head channels;
174 struct list_head global_node;
175
176 struct kref refcount;
177 struct completion done;
178
179 int dev_id;
180
181 int (*device_alloc_chan_resources)(struct dma_chan *chan);
182 void (*device_free_chan_resources)(struct dma_chan *chan);
183 dma_cookie_t (*device_memcpy_buf_to_buf)(struct dma_chan *chan,
184 void *dest, void *src, size_t len);
185 dma_cookie_t (*device_memcpy_buf_to_pg)(struct dma_chan *chan,
186 struct page *page, unsigned int offset, void *kdata,
187 size_t len);
188 dma_cookie_t (*device_memcpy_pg_to_pg)(struct dma_chan *chan,
189 struct page *dest_pg, unsigned int dest_off,
190 struct page *src_pg, unsigned int src_off, size_t len);
191 enum dma_status (*device_memcpy_complete)(struct dma_chan *chan,
192 dma_cookie_t cookie, dma_cookie_t *last,
193 dma_cookie_t *used);
194 void (*device_memcpy_issue_pending)(struct dma_chan *chan);
195};
196
197/* --- public DMA engine API --- */
198
199struct dma_client *dma_async_client_register(dma_event_callback event_callback);
200void dma_async_client_unregister(struct dma_client *client);
201void dma_async_client_chan_request(struct dma_client *client,
202 unsigned int number);
203
204/**
205 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
206 * @chan: DMA channel to offload copy to
207 * @dest: destination address (virtual)
208 * @src: source address (virtual)
209 * @len: length
210 *
211 * Both @dest and @src must be mappable to a bus address according to the
212 * DMA mapping API rules for streaming mappings.
213 * Both @dest and @src must stay memory resident (kernel memory or locked
214 * user space pages)
215 */
216static inline dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
217 void *dest, void *src, size_t len)
218{
219 int cpu = get_cpu();
220 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
221 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
222 put_cpu();
223
224 return chan->device->device_memcpy_buf_to_buf(chan, dest, src, len);
225}
226
227/**
228 * dma_async_memcpy_buf_to_pg - offloaded copy
229 * @chan: DMA channel to offload copy to
230 * @page: destination page
231 * @offset: offset in page to copy to
232 * @kdata: source address (virtual)
233 * @len: length
234 *
235 * Both @page/@offset and @kdata must be mappable to a bus address according
236 * to the DMA mapping API rules for streaming mappings.
237 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
238 * locked user space pages)
239 */
240static inline dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,
241 struct page *page, unsigned int offset, void *kdata, size_t len)
242{
243 int cpu = get_cpu();
244 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
245 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
246 put_cpu();
247
248 return chan->device->device_memcpy_buf_to_pg(chan, page, offset,
249 kdata, len);
250}
251
252/**
253 * dma_async_memcpy_buf_to_pg - offloaded copy
254 * @chan: DMA channel to offload copy to
255 * @dest_page: destination page
256 * @dest_off: offset in page to copy to
257 * @src_page: source page
258 * @src_off: offset in page to copy from
259 * @len: length
260 *
261 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
262 * address according to the DMA mapping API rules for streaming mappings.
263 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
264 * (kernel memory or locked user space pages)
265 */
266static inline dma_cookie_t dma_async_memcpy_pg_to_pg(struct dma_chan *chan,
267 struct page *dest_pg, unsigned int dest_off, struct page *src_pg,
268 unsigned int src_off, size_t len)
269{
270 int cpu = get_cpu();
271 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
272 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
273 put_cpu();
274
275 return chan->device->device_memcpy_pg_to_pg(chan, dest_pg, dest_off,
276 src_pg, src_off, len);
277}
278
279/**
280 * dma_async_memcpy_issue_pending - flush pending copies to HW
281 * @chan:
282 *
283 * This allows drivers to push copies to HW in batches,
284 * reducing MMIO writes where possible.
285 */
286static inline void dma_async_memcpy_issue_pending(struct dma_chan *chan)
287{
288 return chan->device->device_memcpy_issue_pending(chan);
289}
290
291/**
292 * dma_async_memcpy_complete - poll for transaction completion
293 * @chan: DMA channel
294 * @cookie: transaction identifier to check status of
295 * @last: returns last completed cookie, can be NULL
296 * @used: returns last issued cookie, can be NULL
297 *
298 * If @last and @used are passed in, upon return they reflect the driver
299 * internal state and can be used with dma_async_is_complete() to check
300 * the status of multiple cookies without re-checking hardware state.
301 */
302static inline enum dma_status dma_async_memcpy_complete(struct dma_chan *chan,
303 dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
304{
305 return chan->device->device_memcpy_complete(chan, cookie, last, used);
306}
307
308/**
309 * dma_async_is_complete - test a cookie against chan state
310 * @cookie: transaction identifier to test status of
311 * @last_complete: last know completed transaction
312 * @last_used: last cookie value handed out
313 *
314 * dma_async_is_complete() is used in dma_async_memcpy_complete()
315 * the test logic is seperated for lightweight testing of multiple cookies
316 */
317static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
318 dma_cookie_t last_complete, dma_cookie_t last_used)
319{
320 if (last_complete <= last_used) {
321 if ((cookie <= last_complete) || (cookie > last_used))
322 return DMA_SUCCESS;
323 } else {
324 if ((cookie <= last_complete) && (cookie > last_used))
325 return DMA_SUCCESS;
326 }
327 return DMA_IN_PROGRESS;
328}
329
330
331/* --- DMA device --- */
332
333int dma_async_device_register(struct dma_device *device);
334void dma_async_device_unregister(struct dma_device *device);
335
336#endif /* CONFIG_DMA_ENGINE */
337#endif /* DMAENGINE_H */