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/*
* Copyright (c) 1994 John S. Dyson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice immediately at the beginning of the file, without modification,
* this list of conditions, and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Absolutely no warranty of function or purpose is made by the author
* John S. Dyson.
* 4. Modifications may be freely made to this file if the above conditions
* are met.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/proc.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_extern.h>
static void physwakeup __P((struct buf *bp));
int
physio(strategy, bp, dev, rw, minp, uio)
d_strategy_t *strategy;
struct buf *bp;
dev_t dev;
int rw;
u_int (*minp) __P((struct buf *bp));
struct uio *uio;
{
int i;
int bufflags = rw?B_READ:0;
int error;
int spl;
caddr_t sa;
int bp_alloc = (bp == 0);
struct buf *bpa;
/*
* keep the process from being swapped
*/
curproc->p_flag |= P_PHYSIO;
/* create and build a buffer header for a transfer */
bpa = (struct buf *)getpbuf();
if (!bp_alloc) {
spl = splbio();
while (bp->b_flags & B_BUSY) {
bp->b_flags |= B_WANTED;
tsleep((caddr_t)bp, PRIBIO, "physbw", 0);
}
bp->b_flags |= B_BUSY;
splx(spl);
} else {
bp = bpa;
}
/*
* get a copy of the kva from the physical buffer
*/
sa = bpa->b_data;
bp->b_proc = curproc;
bp->b_dev = dev;
error = bp->b_error = 0;
for(i=0;i<uio->uio_iovcnt;i++) {
while( uio->uio_iov[i].iov_len) {
bp->b_bcount = uio->uio_iov[i].iov_len;
bp->b_flags = B_BUSY | B_PHYS | B_CALL | bufflags;
bp->b_iodone = physwakeup;
bp->b_data = uio->uio_iov[i].iov_base;
bp->b_bcount = minp( bp);
if( minp != minphys)
bp->b_bcount = minphys( bp);
bp->b_bufsize = bp->b_bcount;
/*
* pass in the kva from the physical buffer
* for the temporary kernel mapping.
*/
bp->b_saveaddr = sa;
bp->b_blkno = btodb(uio->uio_offset);
if (uio->uio_segflg == UIO_USERSPACE) {
if (rw && !useracc(bp->b_data, bp->b_bufsize, B_WRITE)) {
error = EFAULT;
goto doerror;
}
if (!rw && !useracc(bp->b_data, bp->b_bufsize, B_READ)) {
error = EFAULT;
goto doerror;
}
/* bring buffer into kernel space */
vmapbuf(bp);
}
/* perform transfer */
(*strategy)(bp);
spl = splbio();
while ((bp->b_flags & B_DONE) == 0)
tsleep((caddr_t)bp, PRIBIO, "physstr", 0);
splx(spl);
/* release mapping into kernel space */
if (uio->uio_segflg == UIO_USERSPACE)
vunmapbuf(bp);
/*
* update the uio data
*/
{
int iolen = bp->b_bcount - bp->b_resid;
if (iolen == 0 && !(bp->b_flags & B_ERROR))
goto doerror; /* EOF */
uio->uio_iov[i].iov_len -= iolen;
uio->uio_iov[i].iov_base += iolen;
uio->uio_resid -= iolen;
uio->uio_offset += iolen;
}
/*
* check for an error
*/
if( bp->b_flags & B_ERROR) {
error = bp->b_error;
goto doerror;
}
}
}
doerror:
relpbuf(bpa);
if (!bp_alloc) {
bp->b_flags &= ~(B_BUSY|B_PHYS);
if( bp->b_flags & B_WANTED) {
bp->b_flags &= ~B_WANTED;
wakeup((caddr_t)bp);
}
}
/*
* allow the process to be swapped
*/
curproc->p_flag &= ~P_PHYSIO;
return (error);
}
u_int
minphys(struct buf *bp)
{
u_int maxphys = MAXPHYS;
if( ((vm_offset_t) bp->b_data) & PAGE_MASK) {
maxphys = MAXPHYS - PAGE_SIZE;
}
if( bp->b_bcount > maxphys) {
bp->b_bcount = maxphys;
}
return bp->b_bcount;
}
int
rawread(dev_t dev, struct uio *uio, int ioflag)
{
return (physio(cdevsw[major(dev)]->d_strategy, (struct buf *)NULL,
dev, 1, minphys, uio));
}
int
rawwrite(dev_t dev, struct uio *uio, int ioflag)
{
return (physio(cdevsw[major(dev)]->d_strategy, (struct buf *)NULL,
dev, 0, minphys, uio));
}
static void
physwakeup(bp)
struct buf *bp;
{
wakeup((caddr_t) bp);
bp->b_flags &= ~B_CALL;
}
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