Change the kernel dev_t, representing a pointer to a specinfo structure,
[dragonfly.git] / sys / vm / device_pager.c
1 /*
2  * Copyright (c) 1990 University of Utah.
3  * Copyright (c) 1991, 1993
4  *      The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * the Systems Programming Group of the University of Utah Computer
8  * Science Department.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *      This product includes software developed by the University of
21  *      California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *      @(#)device_pager.c      8.1 (Berkeley) 6/11/93
39  * $FreeBSD: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $
40  * $DragonFly: src/sys/vm/device_pager.c,v 1.11 2006/09/10 01:26:41 dillon Exp $
41  */
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/conf.h>
46 #include <sys/mman.h>
47 #include <sys/device.h>
48 #include <sys/thread2.h>
49
50 #include <vm/vm.h>
51 #include <vm/vm_object.h>
52 #include <vm/vm_page.h>
53 #include <vm/vm_pager.h>
54 #include <vm/vm_zone.h>
55
56 static void dev_pager_init (void);
57 static vm_object_t dev_pager_alloc (void *, off_t, vm_prot_t, off_t);
58 static void dev_pager_dealloc (vm_object_t);
59 static int dev_pager_getpages (vm_object_t, vm_page_t *, int, int);
60 static void dev_pager_putpages (vm_object_t, vm_page_t *, int, 
61                 boolean_t, int *);
62 static boolean_t dev_pager_haspage (vm_object_t, vm_pindex_t, int *,
63                 int *);
64
65 /* list of device pager objects */
66 static struct pagerlst dev_pager_object_list;
67
68 static vm_zone_t fakepg_zone;
69 static struct vm_zone fakepg_zone_store;
70
71 static vm_page_t dev_pager_getfake (vm_paddr_t);
72 static void dev_pager_putfake (vm_page_t);
73
74 static int dev_pager_alloc_lock, dev_pager_alloc_lock_want;
75
76 struct pagerops devicepagerops = {
77         dev_pager_init,
78         dev_pager_alloc,
79         dev_pager_dealloc,
80         dev_pager_getpages,
81         dev_pager_putpages,
82         dev_pager_haspage,
83         NULL
84 };
85
86 static void
87 dev_pager_init(void)
88 {
89         TAILQ_INIT(&dev_pager_object_list);
90         fakepg_zone = &fakepg_zone_store;
91         zinitna(fakepg_zone, NULL, "DP fakepg", sizeof(struct vm_page), 0, 0, 2);
92 }
93
94 static vm_object_t
95 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff)
96 {
97         cdev_t dev;
98         vm_object_t object;
99         unsigned int npages;
100         vm_offset_t off;
101
102         /*
103          * Make sure this device can be mapped.
104          */
105         dev = handle;
106
107         /*
108          * Offset should be page aligned.
109          */
110         if (foff & PAGE_MASK)
111                 return (NULL);
112
113         size = round_page(size);
114
115         /*
116          * Check that the specified range of the device allows the desired
117          * protection.
118          *
119          * XXX assumes VM_PROT_* == PROT_*
120          */
121         npages = OFF_TO_IDX(size);
122         for (off = foff; npages--; off += PAGE_SIZE) {
123                 if (dev_dmmap(dev, off, (int)prot) == -1)
124                         return (NULL);
125         }
126
127         /*
128          * Lock to prevent object creation race condition.
129          */
130         while (dev_pager_alloc_lock) {
131                 dev_pager_alloc_lock_want++;
132                 tsleep(&dev_pager_alloc_lock, 0, "dvpall", 0);
133                 dev_pager_alloc_lock_want--;
134         }
135         dev_pager_alloc_lock = 1;
136
137         /*
138          * Look up pager, creating as necessary.
139          */
140         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
141         if (object == NULL) {
142                 /*
143                  * Allocate object and associate it with the pager.
144                  */
145                 object = vm_object_allocate(OBJT_DEVICE,
146                         OFF_TO_IDX(foff + size));
147                 object->handle = handle;
148                 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
149                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list);
150         } else {
151                 /*
152                  * Gain a reference to the object.
153                  */
154                 vm_object_reference(object);
155                 if (OFF_TO_IDX(foff + size) > object->size)
156                         object->size = OFF_TO_IDX(foff + size);
157         }
158
159         dev_pager_alloc_lock = 0;
160         if (dev_pager_alloc_lock_want)
161                 wakeup(&dev_pager_alloc_lock);
162
163         return (object);
164 }
165
166 static void
167 dev_pager_dealloc(vm_object_t object)
168 {
169         vm_page_t m;
170
171         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
172         /*
173          * Free up our fake pages.
174          */
175         while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
176                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
177                 dev_pager_putfake(m);
178         }
179 }
180
181 static int
182 dev_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
183 {
184         vm_offset_t offset;
185         vm_paddr_t paddr;
186         vm_page_t page;
187         cdev_t dev;
188         int prot;
189         int i;
190
191         dev = object->handle;
192         offset = m[reqpage]->pindex;
193         prot = PROT_READ;       /* XXX should pass in? */
194
195         paddr = pmap_phys_address(dev_dmmap(dev, (vm_offset_t) offset << PAGE_SHIFT, prot));
196         KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
197
198         if (m[reqpage]->flags & PG_FICTITIOUS) {
199                 /*
200                  * If the passed in reqpage page is a fake page, update it
201                  * with the new physical address.
202                  */
203                 m[reqpage]->phys_addr = paddr;
204         } else {
205                 /*
206                  * Replace the passed in reqpage page with our own fake page
207                  * and free up all the original pages.
208                  */
209                 page = dev_pager_getfake(paddr);
210                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
211                 crit_enter();
212                 vm_page_free(m[reqpage]);
213                 vm_page_insert(page, object, offset);
214                 crit_exit();
215         }
216         for (i = 0; i < count; i++) {
217                 if (i != reqpage)
218                         vm_page_free(m[i]);
219         }
220         return (VM_PAGER_OK);
221 }
222
223 static void
224 dev_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync,
225     int *rtvals)
226 {
227         panic("dev_pager_putpage called");
228 }
229
230 static boolean_t
231 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
232     int *after)
233 {
234         if (before != NULL)
235                 *before = 0;
236         if (after != NULL)
237                 *after = 0;
238         return (TRUE);
239 }
240
241 static vm_page_t
242 dev_pager_getfake(vm_paddr_t paddr)
243 {
244         vm_page_t m;
245
246         m = zalloc(fakepg_zone);
247
248         m->flags = PG_BUSY | PG_FICTITIOUS;
249         m->valid = VM_PAGE_BITS_ALL;
250         m->dirty = 0;
251         m->busy = 0;
252         m->queue = PQ_NONE;
253         m->object = NULL;
254
255         m->wire_count = 1;
256         m->hold_count = 0;
257         m->phys_addr = paddr;
258
259         return (m);
260 }
261
262 static void
263 dev_pager_putfake(vm_page_t m)
264 {
265         if (!(m->flags & PG_FICTITIOUS))
266                 panic("dev_pager_putfake: bad page");
267         KKASSERT(m->object == NULL);
268         zfree(fakepg_zone, m);
269 }
270