1 /* $NetBSD: shmif_busops.c,v 1.6 2010/08/17 11:35:23 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 2009 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 #include <sys/cdefs.h> 31 __KERNEL_RCSID(0, "$NetBSD: shmif_busops.c,v 1.6 2010/08/17 11:35:23 pooka Exp $"); 32 33 #include <sys/param.h> 34 #include <sys/atomic.h> 35 36 #include "shmifvar.h" 37 38 #ifndef _KERNEL 39 #include <assert.h> 40 #define KASSERT(a) assert(a) 41 #else 42 #include <rump/rumpuser.h> 43 #endif 44 45 uint32_t 46 shmif_advance(uint32_t oldoff, uint32_t delta) 47 { 48 uint32_t newoff; 49 50 newoff = oldoff + delta; 51 if (newoff >= BUSMEM_DATASIZE) 52 newoff -= BUSMEM_DATASIZE; 53 return newoff; 54 } 55 56 uint32_t 57 shmif_busread(struct shmif_mem *busmem, void *dest, uint32_t off, size_t len, 58 bool *wrap) 59 { 60 size_t chunk; 61 62 KASSERT(len < (BUSMEM_DATASIZE/2) && off <= BUSMEM_DATASIZE); 63 chunk = MIN(len, BUSMEM_DATASIZE - off); 64 memcpy(dest, busmem->shm_data + off, chunk); 65 len -= chunk; 66 67 if (off + chunk == BUSMEM_DATASIZE) 68 *wrap = true; 69 70 if (len == 0) { 71 return (off + chunk) % BUSMEM_DATASIZE; 72 } 73 74 /* finish reading */ 75 memcpy((uint8_t *)dest + chunk, busmem->shm_data, len); 76 return len; 77 } 78 79 void 80 shmif_advancefirst(struct shmif_mem *busmem, uint32_t off, size_t len) 81 { 82 83 while (off <= busmem->shm_first + sizeof(struct shmif_pkthdr) 84 && off+len > busmem->shm_first) { 85 DPRINTF(("advancefirst: old offset %d, ", busmem->shm_first)); 86 busmem->shm_first = shmif_nextpktoff(busmem, busmem->shm_first); 87 DPRINTF(("new offset: %d\n", busmem->shm_first)); 88 } 89 } 90 91 uint32_t 92 shmif_buswrite(struct shmif_mem *busmem, uint32_t off, void *data, size_t len, 93 bool *wrap) 94 { 95 size_t chunk; 96 97 KASSERT(len < (BUSMEM_DATASIZE/2) && off <= BUSMEM_DATASIZE); 98 99 chunk = MIN(len, BUSMEM_DATASIZE - off); 100 len -= chunk; 101 102 shmif_advancefirst(busmem, off, chunk + (len ? 1 : 0)); 103 104 memcpy(busmem->shm_data + off, data, chunk); 105 106 DPRINTF(("buswrite: wrote %d bytes to %d", chunk, off)); 107 108 if (off + chunk == BUSMEM_DATASIZE) 109 *wrap = true; 110 111 if (len == 0) { 112 DPRINTF(("\n")); 113 return (off + chunk) % BUSMEM_DATASIZE; 114 } 115 116 DPRINTF((", wrapped bytes %d to 0\n", len)); 117 118 shmif_advancefirst(busmem, 0, len); 119 120 /* finish writing */ 121 memcpy(busmem->shm_data, (uint8_t *)data + chunk, len); 122 return len; 123 } 124 125 uint32_t 126 shmif_nextpktoff(struct shmif_mem *busmem, uint32_t oldoff) 127 { 128 struct shmif_pkthdr sp; 129 bool dummy; 130 131 shmif_busread(busmem, &sp, oldoff, sizeof(sp), &dummy); 132 KASSERT(sp.sp_len < BUSMEM_DATASIZE); 133 134 return shmif_advance(oldoff, sizeof(sp) + sp.sp_len); 135 } 136