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Chris Leechc13c8262006-05-23 17:18:44 -07001/*
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
David Woodhouse1c0f16e2006-06-27 02:53:56 -070023
Chris Leechc13c8262006-05-23 17:18:44 -070024#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/**
Randy Dunlapfe4ada22006-07-03 19:44:51 -070047 * typedef dma_cookie_t - an opaque DMA cookie
Chris Leechc13c8262006-05-23 17:18:44 -070048 *
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
Randy Dunlapfe4ada22006-07-03 19:44:51 -070083 * @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
Chris Leechc13c8262006-05-23 17:18:44 -070085 * @cookie: last cookie value returned to client
Randy Dunlapfe4ada22006-07-03 19:44:51 -070086 * @chan_id: channel ID for sysfs
87 * @class_dev: class device for sysfs
Chris Leechc13c8262006-05-23 17:18:44 -070088 * @refcount: kref, used in "bigref" slow-mode
Randy Dunlapfe4ada22006-07-03 19:44:51 -070089 * @slow_ref: indicates that the DMA channel is free
90 * @rcu: the DMA channel's RCU head
Chris Leechc13c8262006-05-23 17:18:44 -070091 * @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
Randy Dunlapfe4ada22006-07-03 19:44:51 -0700165 * @refcount: reference count
166 * @done: IO completion struct
167 * @dev_id: unique device ID
168 * @device_alloc_chan_resources: allocate resources and return the
169 * number of allocated descriptors
170 * @device_free_chan_resources: release DMA channel's resources
171 * @device_memcpy_buf_to_buf: memcpy buf pointer to buf pointer
172 * @device_memcpy_buf_to_pg: memcpy buf pointer to struct page
173 * @device_memcpy_pg_to_pg: memcpy struct page/offset to struct page/offset
174 * @device_memcpy_complete: poll the status of an IOAT DMA transaction
175 * @device_memcpy_issue_pending: push appended descriptors to hardware
Chris Leechc13c8262006-05-23 17:18:44 -0700176 */
177struct dma_device {
178
179 unsigned int chancnt;
180 struct list_head channels;
181 struct list_head global_node;
182
183 struct kref refcount;
184 struct completion done;
185
186 int dev_id;
187
188 int (*device_alloc_chan_resources)(struct dma_chan *chan);
189 void (*device_free_chan_resources)(struct dma_chan *chan);
190 dma_cookie_t (*device_memcpy_buf_to_buf)(struct dma_chan *chan,
191 void *dest, void *src, size_t len);
192 dma_cookie_t (*device_memcpy_buf_to_pg)(struct dma_chan *chan,
193 struct page *page, unsigned int offset, void *kdata,
194 size_t len);
195 dma_cookie_t (*device_memcpy_pg_to_pg)(struct dma_chan *chan,
196 struct page *dest_pg, unsigned int dest_off,
197 struct page *src_pg, unsigned int src_off, size_t len);
198 enum dma_status (*device_memcpy_complete)(struct dma_chan *chan,
199 dma_cookie_t cookie, dma_cookie_t *last,
200 dma_cookie_t *used);
201 void (*device_memcpy_issue_pending)(struct dma_chan *chan);
202};
203
204/* --- public DMA engine API --- */
205
206struct dma_client *dma_async_client_register(dma_event_callback event_callback);
207void dma_async_client_unregister(struct dma_client *client);
208void dma_async_client_chan_request(struct dma_client *client,
209 unsigned int number);
210
211/**
212 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
213 * @chan: DMA channel to offload copy to
214 * @dest: destination address (virtual)
215 * @src: source address (virtual)
216 * @len: length
217 *
218 * Both @dest and @src must be mappable to a bus address according to the
219 * DMA mapping API rules for streaming mappings.
220 * Both @dest and @src must stay memory resident (kernel memory or locked
Randy Dunlapfe4ada22006-07-03 19:44:51 -0700221 * user space pages).
Chris Leechc13c8262006-05-23 17:18:44 -0700222 */
223static inline dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
224 void *dest, void *src, size_t len)
225{
226 int cpu = get_cpu();
227 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
228 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
229 put_cpu();
230
231 return chan->device->device_memcpy_buf_to_buf(chan, dest, src, len);
232}
233
234/**
Randy Dunlapfe4ada22006-07-03 19:44:51 -0700235 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
Chris Leechc13c8262006-05-23 17:18:44 -0700236 * @chan: DMA channel to offload copy to
237 * @page: destination page
238 * @offset: offset in page to copy to
239 * @kdata: source address (virtual)
240 * @len: length
241 *
242 * Both @page/@offset and @kdata must be mappable to a bus address according
243 * to the DMA mapping API rules for streaming mappings.
244 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
245 * locked user space pages)
246 */
247static inline dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,
248 struct page *page, unsigned int offset, void *kdata, size_t len)
249{
250 int cpu = get_cpu();
251 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
252 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
253 put_cpu();
254
255 return chan->device->device_memcpy_buf_to_pg(chan, page, offset,
256 kdata, len);
257}
258
259/**
Randy Dunlapfe4ada22006-07-03 19:44:51 -0700260 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
Chris Leechc13c8262006-05-23 17:18:44 -0700261 * @chan: DMA channel to offload copy to
Randy Dunlapfe4ada22006-07-03 19:44:51 -0700262 * @dest_pg: destination page
Chris Leechc13c8262006-05-23 17:18:44 -0700263 * @dest_off: offset in page to copy to
Randy Dunlapfe4ada22006-07-03 19:44:51 -0700264 * @src_pg: source page
Chris Leechc13c8262006-05-23 17:18:44 -0700265 * @src_off: offset in page to copy from
266 * @len: length
267 *
268 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
269 * address according to the DMA mapping API rules for streaming mappings.
270 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
Randy Dunlapfe4ada22006-07-03 19:44:51 -0700271 * (kernel memory or locked user space pages).
Chris Leechc13c8262006-05-23 17:18:44 -0700272 */
273static inline dma_cookie_t dma_async_memcpy_pg_to_pg(struct dma_chan *chan,
274 struct page *dest_pg, unsigned int dest_off, struct page *src_pg,
275 unsigned int src_off, size_t len)
276{
277 int cpu = get_cpu();
278 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
279 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
280 put_cpu();
281
282 return chan->device->device_memcpy_pg_to_pg(chan, dest_pg, dest_off,
283 src_pg, src_off, len);
284}
285
286/**
287 * dma_async_memcpy_issue_pending - flush pending copies to HW
Randy Dunlapfe4ada22006-07-03 19:44:51 -0700288 * @chan: target DMA channel
Chris Leechc13c8262006-05-23 17:18:44 -0700289 *
290 * This allows drivers to push copies to HW in batches,
291 * reducing MMIO writes where possible.
292 */
293static inline void dma_async_memcpy_issue_pending(struct dma_chan *chan)
294{
295 return chan->device->device_memcpy_issue_pending(chan);
296}
297
298/**
299 * dma_async_memcpy_complete - poll for transaction completion
300 * @chan: DMA channel
301 * @cookie: transaction identifier to check status of
302 * @last: returns last completed cookie, can be NULL
303 * @used: returns last issued cookie, can be NULL
304 *
305 * If @last and @used are passed in, upon return they reflect the driver
306 * internal state and can be used with dma_async_is_complete() to check
307 * the status of multiple cookies without re-checking hardware state.
308 */
309static inline enum dma_status dma_async_memcpy_complete(struct dma_chan *chan,
310 dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
311{
312 return chan->device->device_memcpy_complete(chan, cookie, last, used);
313}
314
315/**
316 * dma_async_is_complete - test a cookie against chan state
317 * @cookie: transaction identifier to test status of
318 * @last_complete: last know completed transaction
319 * @last_used: last cookie value handed out
320 *
321 * dma_async_is_complete() is used in dma_async_memcpy_complete()
322 * the test logic is seperated for lightweight testing of multiple cookies
323 */
324static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
325 dma_cookie_t last_complete, dma_cookie_t last_used)
326{
327 if (last_complete <= last_used) {
328 if ((cookie <= last_complete) || (cookie > last_used))
329 return DMA_SUCCESS;
330 } else {
331 if ((cookie <= last_complete) && (cookie > last_used))
332 return DMA_SUCCESS;
333 }
334 return DMA_IN_PROGRESS;
335}
336
337
338/* --- DMA device --- */
339
340int dma_async_device_register(struct dma_device *device);
341void dma_async_device_unregister(struct dma_device *device);
342
Chris Leechde5506e2006-05-23 17:50:37 -0700343/* --- Helper iov-locking functions --- */
344
345struct dma_page_list {
346 char *base_address;
347 int nr_pages;
348 struct page **pages;
349};
350
351struct dma_pinned_list {
352 int nr_iovecs;
353 struct dma_page_list page_list[0];
354};
355
356struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len);
357void dma_unpin_iovec_pages(struct dma_pinned_list* pinned_list);
358
359dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov,
360 struct dma_pinned_list *pinned_list, unsigned char *kdata, size_t len);
361dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
362 struct dma_pinned_list *pinned_list, struct page *page,
363 unsigned int offset, size_t len);
364
Chris Leechc13c8262006-05-23 17:18:44 -0700365#endif /* CONFIG_DMA_ENGINE */
366#endif /* DMAENGINE_H */