1/*-
2 * CAM request queue management definitions.
3 *
4 * Copyright (c) 1997 Justin T. Gibbs.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions, and the following disclaimer,
12 *    without modification, immediately at the beginning of the file.
13 * 2. The name of the author may not be used to endorse or promote products
14 *    derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
20 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#ifndef _CAM_CAM_QUEUE_H
32#define _CAM_CAM_QUEUE_H 1
33
34#ifdef _KERNEL
35
36#include <sys/queue.h>
37#include <cam/cam.h>
38
39/*
40 * This structure implements a heap based priority queue.  The queue
41 * assumes that the objects stored in it begin with a cam_qentry
42 * structure holding the priority information used to sort the objects.
43 * This structure is opaque to clients (outside of the XPT layer) to allow
44 * the implementation to change without affecting them.
45 */
46struct camq {
47	cam_pinfo **queue_array;
48	int	   array_size;
49	int	   entries;
50	u_int32_t  generation;
51	u_int32_t  qfrozen_cnt;
52};
53
54TAILQ_HEAD(ccb_hdr_tailq, ccb_hdr);
55LIST_HEAD(ccb_hdr_list, ccb_hdr);
56SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
57
58struct cam_ccbq {
59	struct	camq queue;
60	struct ccb_hdr_tailq	queue_extra_head;
61	int	queue_extra_entries;
62	int	devq_openings;
63	int	devq_allocating;
64	int	dev_openings;
65	int	dev_active;
66	int	held;
67};
68
69struct cam_ed;
70
71struct cam_devq {
72	struct	camq send_queue;
73	int	send_openings;
74	int	send_active;
75};
76
77
78struct cam_devq *cam_devq_alloc(int devices, int openings);
79
80int		 cam_devq_init(struct cam_devq *devq, int devices,
81			       int openings);
82
83void		 cam_devq_free(struct cam_devq *devq);
84
85u_int32_t	 cam_devq_resize(struct cam_devq *camq, int openings);
86
87/*
88 * Allocate a cam_ccb_queue structure and initialize it.
89 */
90struct cam_ccbq	*cam_ccbq_alloc(int openings);
91
92u_int32_t	cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
93
94int		cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
95
96void		cam_ccbq_free(struct cam_ccbq *ccbq);
97
98void		cam_ccbq_fini(struct cam_ccbq *ccbq);
99
100/*
101 * Allocate and initialize a cam_queue structure.
102 */
103struct camq	*camq_alloc(int size);
104
105/*
106 * Resize a cam queue
107 */
108u_int32_t	camq_resize(struct camq *queue, int new_size);
109
110/*
111 * Initialize a camq structure.  Return 0 on success, 1 on failure.
112 */
113int		camq_init(struct camq *camq, int size);
114
115/*
116 * Free a cam_queue structure.  This should only be called if a controller
117 * driver failes somehow during its attach routine or is unloaded and has
118 * obtained a cam_queue structure.
119 */
120void		camq_free(struct camq *queue);
121
122/*
123 * Finialize any internal storage or state of a cam_queue.
124 */
125void		camq_fini(struct camq *queue);
126
127/*
128 * cam_queue_insert: Given a CAM queue with at least one open spot,
129 * insert the new entry maintaining order.
130 */
131void		camq_insert(struct camq *queue, cam_pinfo *new_entry);
132
133/*
134 * camq_remove: Remove and arbitrary entry from the queue maintaining
135 * queue order.
136 */
137cam_pinfo	*camq_remove(struct camq *queue, int index);
138#define CAMQ_HEAD 1	/* Head of queue index */
139
140/* Index the first element in the heap */
141#define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
142
143/* Get the first element priority. */
144#define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ?			\
145			    ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
146
147/*
148 * camq_change_priority: Raise or lower the priority of an entry
149 * maintaining queue order.
150 */
151void		camq_change_priority(struct camq *queue, int index,
152				     u_int32_t new_priority);
153
154static __inline int
155cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq);
156
157static __inline void
158cam_ccbq_take_opening(struct cam_ccbq *ccbq);
159
160static __inline void
161cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb);
162
163static __inline void
164cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb);
165
166static __inline union ccb *
167cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index);
168
169static __inline void
170cam_ccbq_send_ccb(struct cam_ccbq *queue, union ccb *send_ccb);
171
172static __inline void
173cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb);
174
175static __inline void
176cam_ccbq_release_opening(struct cam_ccbq *ccbq);
177
178
179static __inline int
180cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
181{
182	return (ccbq->queue.entries + ccbq->queue_extra_entries);
183}
184
185static __inline void
186cam_ccbq_take_opening(struct cam_ccbq *ccbq)
187{
188	ccbq->devq_openings--;
189	ccbq->held++;
190}
191
192static __inline void
193cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
194{
195	struct ccb_hdr *old_ccb;
196	struct camq *queue = &ccbq->queue;
197
198	ccbq->held--;
199
200	/*
201	 * If queue is already full, try to resize.
202	 * If resize fail, push CCB with lowest priority out to the TAILQ.
203	 */
204	if (queue->entries == queue->array_size &&
205	    camq_resize(&ccbq->queue, queue->array_size * 2) != CAM_REQ_CMP) {
206		old_ccb = (struct ccb_hdr *)camq_remove(queue, queue->entries);
207		TAILQ_INSERT_HEAD(&ccbq->queue_extra_head, old_ccb,
208		    xpt_links.tqe);
209		old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
210		ccbq->queue_extra_entries++;
211	}
212
213	camq_insert(queue, &new_ccb->ccb_h.pinfo);
214}
215
216static __inline void
217cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
218{
219	struct ccb_hdr *cccb, *bccb;
220	struct camq *queue = &ccbq->queue;
221
222	/* If the CCB is on the TAILQ, remove it from there. */
223	if (ccb->ccb_h.pinfo.index == CAM_EXTRAQ_INDEX) {
224		TAILQ_REMOVE(&ccbq->queue_extra_head, &ccb->ccb_h,
225		    xpt_links.tqe);
226		ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
227		ccbq->queue_extra_entries--;
228		return;
229	}
230
231	camq_remove(queue, ccb->ccb_h.pinfo.index);
232
233	/*
234	 * If there are some CCBs on TAILQ, find the best one and move it
235	 * to the emptied space in the queue.
236	 */
237	bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
238	if (bccb == NULL)
239		return;
240	TAILQ_FOREACH(cccb, &ccbq->queue_extra_head, xpt_links.tqe) {
241		if (bccb->pinfo.priority > cccb->pinfo.priority ||
242		    (bccb->pinfo.priority == cccb->pinfo.priority &&
243		     GENERATIONCMP(bccb->pinfo.generation, >,
244		      cccb->pinfo.generation)))
245		        bccb = cccb;
246	}
247	TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
248	ccbq->queue_extra_entries--;
249	camq_insert(queue, &bccb->pinfo);
250}
251
252static __inline union ccb *
253cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
254{
255	return((union ccb *)ccbq->queue.queue_array[index]);
256}
257
258static __inline void
259cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
260{
261
262	send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
263	ccbq->dev_active++;
264	ccbq->dev_openings--;
265}
266
267static __inline void
268cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
269{
270
271	ccbq->dev_active--;
272	ccbq->dev_openings++;
273	ccbq->held++;
274}
275
276static __inline void
277cam_ccbq_release_opening(struct cam_ccbq *ccbq)
278{
279	ccbq->held--;
280	ccbq->devq_openings++;
281}
282
283#endif /* _KERNEL */
284#endif  /* _CAM_CAM_QUEUE_H */
285