1 /* $NetBSD: shmif_busops.c,v 1.12 2014/09/17 04:20:58 ozaki-r Exp $ */
2
3 /*
4 * Copyright (c) 2009, 2010 Antti Kantee. All Rights Reserved.
5 *
6 * Development of this software was supported by The Nokia Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
18 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #ifdef _KERNEL
31 #include <sys/cdefs.h>
32 __KERNEL_RCSID(0, "$NetBSD: shmif_busops.c,v 1.12 2014/09/17 04:20:58 ozaki-r Exp $");
33 #else
34 #include <rump/rumpuser_port.h>
35 __RCSID("$NetBSD: shmif_busops.c,v 1.12 2014/09/17 04:20:58 ozaki-r Exp $");
36 #endif
37
38 #include <sys/param.h>
39
40 #ifndef _KERNEL
41 #include <assert.h>
42 #include <inttypes.h>
43 #include <stdbool.h>
44 #include <string.h>
45
46 #define KASSERT(a) assert(a)
47 #endif
48
49 #include "shmifvar.h"
50
51 uint32_t
shmif_advance(uint32_t oldoff,uint32_t delta)52 shmif_advance(uint32_t oldoff, uint32_t delta)
53 {
54 uint32_t newoff;
55
56 newoff = oldoff + delta;
57 if (newoff >= BUSMEM_DATASIZE)
58 newoff -= BUSMEM_DATASIZE;
59 return newoff;
60 }
61
62 uint32_t
shmif_busread(struct shmif_mem * busmem,void * dest,uint32_t off,size_t len,bool * wrap)63 shmif_busread(struct shmif_mem *busmem, void *dest, uint32_t off, size_t len,
64 bool *wrap)
65 {
66 size_t chunk;
67
68 KASSERT(len < (BUSMEM_DATASIZE/2) && off <= BUSMEM_DATASIZE);
69 chunk = MIN(len, BUSMEM_DATASIZE - off);
70 memcpy(dest, busmem->shm_data + off, chunk);
71 len -= chunk;
72
73 if (off + chunk == BUSMEM_DATASIZE)
74 *wrap = true;
75
76 if (len == 0) {
77 return (off + chunk) % BUSMEM_DATASIZE;
78 }
79
80 /* finish reading */
81 memcpy((uint8_t *)dest + chunk, busmem->shm_data, len);
82 return len;
83 }
84
85 void
shmif_advancefirst(struct shmif_mem * busmem,uint32_t off,size_t len)86 shmif_advancefirst(struct shmif_mem *busmem, uint32_t off, size_t len)
87 {
88
89 while (off <= busmem->shm_first + sizeof(struct shmif_pkthdr)
90 && off+len > busmem->shm_first) {
91 DPRINTF(("advancefirst: old offset %d, ", busmem->shm_first));
92 busmem->shm_first = shmif_nextpktoff(busmem, busmem->shm_first);
93 DPRINTF(("new offset: %d\n", busmem->shm_first));
94 }
95 }
96
97 uint32_t
shmif_buswrite(struct shmif_mem * busmem,uint32_t off,void * data,size_t len,bool * wrap)98 shmif_buswrite(struct shmif_mem *busmem, uint32_t off, void *data, size_t len,
99 bool *wrap)
100 {
101 size_t chunk;
102 bool filledbus;
103
104 KASSERT(len < (BUSMEM_DATASIZE/2) && off <= BUSMEM_DATASIZE);
105
106 chunk = MIN(len, BUSMEM_DATASIZE - off);
107 len -= chunk;
108 filledbus = (off+chunk == BUSMEM_DATASIZE);
109
110 shmif_advancefirst(busmem, off, chunk + (filledbus ? 1 : 0));
111
112 memcpy(busmem->shm_data + off, data, chunk);
113
114 DPRINTF(("buswrite: wrote %zu bytes to %d", chunk, off));
115
116 if (filledbus) {
117 *wrap = true;
118 }
119
120 if (len == 0) {
121 DPRINTF(("\n"));
122 return (off + chunk) % BUSMEM_DATASIZE;
123 }
124
125 DPRINTF((", wrapped bytes %zu to 0\n", len));
126
127 shmif_advancefirst(busmem, 0, len);
128
129 /* finish writing */
130 memcpy(busmem->shm_data, (uint8_t *)data + chunk, len);
131 return len;
132 }
133
134 uint32_t
shmif_nextpktoff(struct shmif_mem * busmem,uint32_t oldoff)135 shmif_nextpktoff(struct shmif_mem *busmem, uint32_t oldoff)
136 {
137 struct shmif_pkthdr sp;
138 bool dummy;
139
140 shmif_busread(busmem, &sp, oldoff, sizeof(sp), &dummy);
141 KASSERT(sp.sp_len < BUSMEM_DATASIZE);
142
143 return shmif_advance(oldoff, sizeof(sp) + sp.sp_len);
144 }
145