/*
* smbus_request_bus()
*
* Allocate the device to perform transfers.
*
* how : SMB_WAIT or SMB_DONTWAIT
*/
int
smbus_request_bus(device_t bus, device_t dev, int how)
{
struct smbus_softc *sc = (struct smbus_softc *)device_get_softc(bus);
int s, error = 0;
/* first, ask the underlying layers if the request is ok */
do {
error = SMBUS_CALLBACK(device_get_parent(bus),
SMB_REQUEST_BUS, (caddr_t)&how);
if (error)
error = smbus_poll(sc, how);
} while (error == EWOULDBLOCK);
while (!error) {
s = splhigh();
if (sc->owner && sc->owner != dev) {
splx(s);
error = smbus_poll(sc, how);
} else {
sc->owner = dev;
splx(s);
return (0);
}
/* free any allocated resource */
if (error)
SMBUS_CALLBACK(device_get_parent(bus), SMB_RELEASE_BUS,
(caddr_t)&how);
}
return (error);
}
/*
* smbus_release_bus()
*
* Release the device allocated with smbus_request_dev()
*/
int
smbus_release_bus(device_t bus, device_t dev)
{
struct smbus_softc *sc = (struct smbus_softc *)device_get_softc(bus);
int s, error;
/* first, ask the underlying layers if the release is ok */
error = SMBUS_CALLBACK(device_get_parent(bus), SMB_RELEASE_BUS, NULL);
if (error)
return (error);
s = splhigh();
if (sc->owner != dev) {
splx(s);
return (EACCES);
}
sc->owner = 0;
splx(s);
/* wakeup waiting processes */
wakeup(sc);
return (0);
}
/*
* smbus_request_bus()
*
* Allocate the device to perform transfers.
*
* how : SMB_WAIT or SMB_DONTWAIT
*/
int
smbus_request_bus(device_t bus, device_t dev, int how)
{
struct smbus_softc *sc = device_get_softc(bus);
device_t parent;
int error;
/* first, ask the underlying layers if the request is ok */
parent = device_get_parent(bus);
mtx_lock(&sc->lock);
do {
mtx_unlock(&sc->lock);
error = SMBUS_CALLBACK(parent, SMB_REQUEST_BUS, &how);
mtx_lock(&sc->lock);
if (error)
error = smbus_poll(sc, how);
} while (error == EWOULDBLOCK);
while (error == 0) {
if (sc->owner && sc->owner != dev)
error = smbus_poll(sc, how);
else {
sc->owner = dev;
break;
}
/* free any allocated resource */
if (error) {
mtx_unlock(&sc->lock);
SMBUS_CALLBACK(parent, SMB_RELEASE_BUS, &how);
return (error);
}
}
mtx_unlock(&sc->lock);
return (error);
}
/*
* smbus_release_bus()
*
* Release the device allocated with smbus_request_dev()
*/
int
smbus_release_bus(device_t bus, device_t dev)
{
struct smbus_softc *sc = device_get_softc(bus);
int error;
/* first, ask the underlying layers if the release is ok */
error = SMBUS_CALLBACK(device_get_parent(bus), SMB_RELEASE_BUS, NULL);
if (error)
return (error);
mtx_lock(&sc->lock);
if (sc->owner == dev) {
sc->owner = NULL;
/* wakeup waiting processes */
wakeup(sc);
} else
error = EACCES;
mtx_unlock(&sc->lock);
return (error);
}
