freebsd-skq/sys/dev/iicbus/iicbus.c
John Baldwin 313f8941e1 Add locking to the core iicbus(4) drivers:
- Add an sx lock to the iic(4) driver to serialize open(), close(), read(),
  and write and to protect sc_addr and sc_count in the softc.
- Use cdev->si_drv1 instead of using the minor number of the cdev to
  lookup the softc via newbus in iic(4).
- Store the device_t in the softc to avoid a similar detour via minor
  numbers in iic(4).
- Only add at most one instance of iic(4) and iicsmb(4) to each iicbus(4)
  instance, and do it in the child driver.
- Add a mutex to the iicbus(4) softc to synchronize the request/release bus
  stuff.
- Use __BUS_ACCESSOR() for IICBUS_ACCESSOR() instead of rolling our own.
- Add a mutex to the iicsmb(4) softc to protect softc state updated in the
  interrupt handler.
- Remove Giant from all the smbus methods in iicsmb(4) now that all the
  iicbus(4) backend is locked.
2008-08-04 21:03:06 +00:00

269 lines
6.4 KiB
C

/*-
* Copyright (c) 1998, 2001 Nicolas Souchu
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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("$FreeBSD$");
/*
* Autoconfiguration and support routines for the Philips serial I2C bus
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/bus.h>
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
#include "iicbus_if.h"
/* See comments below for why auto-scanning is a bad idea. */
#define SCAN_IICBUS 0
static int
iicbus_probe(device_t dev)
{
device_set_desc(dev, "Philips I2C bus");
return (0);
}
#if SCAN_IICBUS
static int
iic_probe_device(device_t dev, u_char addr)
{
int count;
char byte;
if ((addr & 1) == 0) {
/* is device writable? */
if (!iicbus_start(dev, (u_char)addr, 0)) {
iicbus_stop(dev);
return (1);
}
} else {
/* is device readable? */
if (!iicbus_block_read(dev, (u_char)addr, &byte, 1, &count))
return (1);
}
return (0);
}
#endif
/*
* We add all the devices which we know about.
* The generic attach routine will attach them if they are alive.
*/
static int
iicbus_attach(device_t dev)
{
#if SCAN_IICBUS
unsigned char addr;
#endif
struct iicbus_softc *sc = IICBUS_SOFTC(dev);
sc->dev = dev;
mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
iicbus_reset(dev, IIC_FASTEST, 0, NULL);
/* device probing is meaningless since the bus is supposed to be
* hot-plug. Moreover, some I2C chips do not appreciate random
* accesses like stop after start to fast, reads for less than
* x bytes...
*/
#if SCAN_IICBUS
printf("Probing for devices on iicbus%d:", device_get_unit(dev));
/* probe any devices */
for (addr = 16; addr < 240; addr++) {
if (iic_probe_device(dev, (u_char)addr)) {
printf(" <%x>", addr);
}
}
printf("\n");
#endif
bus_generic_probe(dev);
bus_enumerate_hinted_children(dev);
bus_generic_attach(dev);
return (0);
}
static int
iicbus_detach(device_t dev)
{
struct iicbus_softc *sc = IICBUS_SOFTC(dev);
iicbus_reset(dev, IIC_FASTEST, 0, NULL);
bus_generic_detach(dev);
mtx_destroy(&sc->lock);
return (0);
}
static int
iicbus_print_child(device_t dev, device_t child)
{
struct iicbus_ivar *devi = IICBUS_IVAR(child);
int retval = 0;
retval += bus_print_child_header(dev, child);
if (devi->addr != 0)
retval += printf(" at addr %#x", devi->addr);
retval += bus_print_child_footer(dev, child);
return (retval);
}
static void
iicbus_probe_nomatch(device_t bus, device_t child)
{
struct iicbus_ivar *devi = IICBUS_IVAR(child);
device_printf(bus, "<unknown card>");
printf(" at addr %#x\n", devi->addr);
return;
}
static int
iicbus_child_location_str(device_t bus, device_t child, char *buf,
size_t buflen)
{
struct iicbus_ivar *devi = IICBUS_IVAR(child);
snprintf(buf, buflen, "addr=%#x", devi->addr);
return (0);
}
static int
iicbus_child_pnpinfo_str(device_t bus, device_t child, char *buf,
size_t buflen)
{
*buf = '\0';
return (0);
}
static int
iicbus_read_ivar(device_t bus, device_t child, int which, u_char *result)
{
struct iicbus_ivar *devi = IICBUS_IVAR(child);
switch (which) {
default:
return (EINVAL);
case IICBUS_IVAR_ADDR:
*(uint32_t *)result = devi->addr;
break;
}
return (0);
}
static device_t
iicbus_add_child(device_t dev, int order, const char *name, int unit)
{
device_t child;
struct iicbus_ivar *devi;
child = device_add_child_ordered(dev, order, name, unit);
if (child == NULL)
return (child);
devi = malloc(sizeof(struct iicbus_ivar), M_DEVBUF, M_NOWAIT | M_ZERO);
if (devi == NULL) {
device_delete_child(dev, child);
return (0);
}
device_set_ivars(child, devi);
return (child);
}
static void
iicbus_hinted_child(device_t bus, const char *dname, int dunit)
{
device_t child;
struct iicbus_ivar *devi;
child = BUS_ADD_CHILD(bus, 0, dname, dunit);
devi = IICBUS_IVAR(child);
resource_int_value(dname, dunit, "addr", &devi->addr);
}
int
iicbus_generic_intr(device_t dev, int event, char *buf)
{
return (0);
}
int
iicbus_null_callback(device_t dev, int index, caddr_t data)
{
return (0);
}
int
iicbus_null_repeated_start(device_t dev, u_char addr)
{
return (IIC_ENOTSUPP);
}
static device_method_t iicbus_methods[] = {
/* device interface */
DEVMETHOD(device_probe, iicbus_probe),
DEVMETHOD(device_attach, iicbus_attach),
DEVMETHOD(device_detach, iicbus_detach),
/* bus interface */
DEVMETHOD(bus_add_child, iicbus_add_child),
DEVMETHOD(bus_driver_added, bus_generic_driver_added),
DEVMETHOD(bus_print_child, iicbus_print_child),
DEVMETHOD(bus_probe_nomatch, iicbus_probe_nomatch),
DEVMETHOD(bus_read_ivar, iicbus_read_ivar),
DEVMETHOD(bus_child_pnpinfo_str, iicbus_child_pnpinfo_str),
DEVMETHOD(bus_child_location_str, iicbus_child_location_str),
DEVMETHOD(bus_hinted_child, iicbus_hinted_child),
/* iicbus interface */
DEVMETHOD(iicbus_transfer, iicbus_transfer),
{ 0, 0 }
};
driver_t iicbus_driver = {
"iicbus",
iicbus_methods,
sizeof(struct iicbus_softc),
};
devclass_t iicbus_devclass;
MODULE_VERSION(iicbus, IICBUS_MODVER);