freebsd-dev/tools/bus_space/bus_space.c
Marcel Moolenaar 0c2b180a35 Add a C libary and a Python module that implements an API similar
to bus_space(9) and that uses the proto(4) driver for talking to
hardware. If the I/O resource is a memory mapped I/O resource,
then mmap(2) will be attempted to avoid read(2)/write(2) overhead.

Sponsored by:	Juniper Networks, Inc.
2014-04-28 18:06:11 +00:00

264 lines
5.1 KiB
C

/*-
* Copyright (c) 2014 Marcel Moolenaar
* 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, 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include "bus_space.h"
#include "../../sys/dev/proto/proto_dev.h"
struct resource {
int rid;
int fd;
long addr;
long size;
off_t ofs;
caddr_t ptr;
};
static struct resource *ridtbl = NULL;
static int nrids = 0;
static int
rid_alloc(void)
{
void *newtbl;
int rid;
for (rid = 0; rid < nrids; rid++) {
if (ridtbl[rid].fd == -1)
break;
}
if (rid == nrids) {
nrids++;
newtbl = realloc(ridtbl, sizeof(struct resource) * nrids);
if (newtbl == NULL) {
nrids--;
return (-1);
} else
ridtbl = newtbl;
}
ridtbl[rid].fd = INT_MAX;
return (rid);
}
static struct resource *
rid_lookup(int rid)
{
struct resource *r;
if (rid < 0 || rid >= nrids) {
errno = EINVAL;
return (NULL);
}
r = ridtbl + rid;
if (r->fd == -1) {
errno = ENXIO;
return (NULL);
}
return (r);
}
int
bs_map(const char *dev)
{
struct proto_ioc_region region;
struct resource *r;
int rid;
rid = rid_alloc();
if (rid == -1)
return (-1);
r = rid_lookup(rid);
if (r == NULL)
return (-1);
r->fd = open(dev, O_RDWR);
if (r->fd == -1)
return (-1);
r->rid = -1;
if (ioctl(r->fd, PROTO_IOC_REGION, &region) == -1) {
close(r->fd);
r->fd = -1;
return (-1);
}
r->addr = region.address;
r->size = region.size;
r->ofs = 0;
r->ptr = mmap(NULL, r->size, PROT_READ | PROT_WRITE,
MAP_NOCORE | MAP_SHARED, r->fd, r->ofs);
return (rid);
}
int
bs_read(int rid, off_t ofs, void *buf, ssize_t bufsz)
{
struct resource *r;
volatile void *ptr;
off_t o;
ssize_t s;
r = rid_lookup(rid);
if (r == NULL)
return (0);
if (ofs < 0 || ofs > r->size - bufsz) {
errno = ESPIPE;
return (0);
}
ofs += r->ofs;
if (r->ptr != MAP_FAILED) {
ptr = r->ptr + ofs;
switch (bufsz) {
case 1:
*((uint8_t *)buf) = *((volatile uint8_t *)ptr);
break;
case 2:
*((uint16_t *)buf) = *((volatile uint16_t *)ptr);
break;
case 4:
*((uint32_t *)buf) = *((volatile uint32_t *)ptr);
break;
default:
errno = EIO;
return (0);
}
} else {
o = lseek(r->fd, ofs, SEEK_SET);
if (o != ofs)
return (0);
s = read(r->fd, buf, bufsz);
if (s != bufsz)
return (0);
}
return (1);
}
int
bs_subregion(int rid0, long ofs, long sz)
{
struct resource *r;
void *ptr0;
long addr0, ofs0;
int fd0, rid;
r = rid_lookup(rid0);
if (r == NULL)
return (-1);
if (ofs < 0 || sz < 1) {
errno = EINVAL;
return (-1);
}
if (ofs + sz > r->size) {
errno = ENOSPC;
return (-1);
}
fd0 = r->fd;
addr0 = r->addr;
ofs0 = r->ofs;
ptr0 = r->ptr;
rid = rid_alloc();
if (rid == -1)
return (-1);
r = rid_lookup(rid);
if (r == NULL)
return (-1);
r->rid = rid0;
r->fd = fd0;
r->addr = addr0 + ofs;
r->size = sz;
r->ofs = ofs0 + ofs;
r->ptr = ptr0;
return (rid);
}
int
bs_unmap(int rid)
{
struct resource *r;
r = rid_lookup(rid);
if (r == NULL)
return (0);
if (r->rid == -1) {
if (r->ptr != MAP_FAILED)
munmap(r->ptr, r->size);
close(r->fd);
}
r->fd = -1;
return (1);
}
int
bs_write(int rid, off_t ofs, void *buf, ssize_t bufsz)
{
struct resource *r;
volatile void *ptr;
off_t o;
ssize_t s;
r = rid_lookup(rid);
if (r == NULL)
return (0);
if (ofs < 0 || ofs > r->size - bufsz) {
errno = ESPIPE;
return (0);
}
ofs += r->ofs;
if (r->ptr != MAP_FAILED) {
ptr = r->ptr + ofs;
switch (bufsz) {
case 1:
*((volatile uint8_t *)ptr) = *((uint8_t *)buf);
break;
case 2:
*((volatile uint16_t *)ptr) = *((uint16_t *)buf);
break;
case 4:
*((volatile uint32_t *)ptr) = *((uint32_t *)buf);
break;
default:
errno = EIO;
return (0);
}
} else {
o = lseek(r->fd, ofs, SEEK_SET);
if (o != ofs)
return (0);
s = write(r->fd, buf, bufsz);
if (s != bufsz)
return (0);
}
return (1);
}