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142 lines
3.8 KiB
C
142 lines
3.8 KiB
C
/* $NetBSD: shmif_busops.c,v 1.9 2011/03/21 16:41:09 pooka Exp $ */
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/*
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* Copyright (c) 2009, 2010 Antti Kantee. All Rights Reserved.
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*
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* Development of this software was supported by The Nokia Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: shmif_busops.c,v 1.9 2011/03/21 16:41:09 pooka Exp $");
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#include <sys/param.h>
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#include <sys/atomic.h>
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#ifndef _KERNEL
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#include <assert.h>
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#include <stdbool.h>
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#include <string.h>
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#define KASSERT(a) assert(a)
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#else
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#include <rump/rumpuser.h>
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#endif
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#include "shmifvar.h"
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uint32_t
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shmif_advance(uint32_t oldoff, uint32_t delta)
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{
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uint32_t newoff;
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newoff = oldoff + delta;
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if (newoff >= BUSMEM_DATASIZE)
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newoff -= BUSMEM_DATASIZE;
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return newoff;
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}
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uint32_t
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shmif_busread(struct shmif_mem *busmem, void *dest, uint32_t off, size_t len,
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bool *wrap)
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{
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size_t chunk;
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KASSERT(len < (BUSMEM_DATASIZE/2) && off <= BUSMEM_DATASIZE);
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chunk = MIN(len, BUSMEM_DATASIZE - off);
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memcpy(dest, busmem->shm_data + off, chunk);
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len -= chunk;
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if (off + chunk == BUSMEM_DATASIZE)
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*wrap = true;
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if (len == 0) {
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return (off + chunk) % BUSMEM_DATASIZE;
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}
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/* finish reading */
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memcpy((uint8_t *)dest + chunk, busmem->shm_data, len);
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return len;
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}
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void
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shmif_advancefirst(struct shmif_mem *busmem, uint32_t off, size_t len)
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{
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while (off <= busmem->shm_first + sizeof(struct shmif_pkthdr)
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&& off+len > busmem->shm_first) {
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DPRINTF(("advancefirst: old offset %d, ", busmem->shm_first));
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busmem->shm_first = shmif_nextpktoff(busmem, busmem->shm_first);
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DPRINTF(("new offset: %d\n", busmem->shm_first));
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}
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}
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uint32_t
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shmif_buswrite(struct shmif_mem *busmem, uint32_t off, void *data, size_t len,
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bool *wrap)
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{
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size_t chunk;
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bool filledbus;
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KASSERT(len < (BUSMEM_DATASIZE/2) && off <= BUSMEM_DATASIZE);
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chunk = MIN(len, BUSMEM_DATASIZE - off);
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len -= chunk;
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filledbus = (off+chunk == BUSMEM_DATASIZE);
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shmif_advancefirst(busmem, off, chunk + (filledbus ? 1 : 0));
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memcpy(busmem->shm_data + off, data, chunk);
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DPRINTF(("buswrite: wrote %d bytes to %d", chunk, off));
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if (filledbus) {
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*wrap = true;
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}
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if (len == 0) {
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DPRINTF(("\n"));
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return (off + chunk) % BUSMEM_DATASIZE;
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}
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DPRINTF((", wrapped bytes %d to 0\n", len));
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shmif_advancefirst(busmem, 0, len);
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/* finish writing */
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memcpy(busmem->shm_data, (uint8_t *)data + chunk, len);
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return len;
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}
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uint32_t
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shmif_nextpktoff(struct shmif_mem *busmem, uint32_t oldoff)
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{
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struct shmif_pkthdr sp;
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bool dummy;
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shmif_busread(busmem, &sp, oldoff, sizeof(sp), &dummy);
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KASSERT(sp.sp_len < BUSMEM_DATASIZE);
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return shmif_advance(oldoff, sizeof(sp) + sp.sp_len);
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}
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