freebsd-nq/sys/dev/smbus/smbconf.c
John Baldwin 7048a99c30 Minor overhaul of SMBus support:
- Change smbus_callback() to pass a void * rather than caddr_t.
- Change smbus_bread() to pass a pointer to the count and have it be an
  in/out parameter.  The input is the size of the buffer (same as before),
  but on return it will contain the actual amount of data read back from
  the bus.  Note that this value may be larger than the input value.  It
  is up to the caller to treat this as an error if desired.
- Change the SMB_BREAD ioctl to write out the updated struct smbcmd which
  will contain the actual number of bytes read in the 'count' field.  To
  preserve the previous ABI, the old ioctl value is mapped to SMB_OLD_BREAD
  which doesn't copy the updated smbcmd back out to userland.  I doubt anyone
  actually used the old BREAD anyway as it was rediculous to do a bulk-read
  but not tell the using program how much data was actually read.
- Make the smbus driver and devclass public in the smbus module and
  push all the DRIVER_MODULE()'s for attaching the smbus driver to
  various foosmb drivers out into the foosmb modules.  This makes all
  the foosmb logic centralized and allows new foosmb modules to be
  self-contained w/o having to hack smbus.c everytime a new smbus driver
  is added.
- Add a new SMB_EINVAL error bit and use it in place of EINVAL to return
  an error for bad arguments (such as invalid counts for bread and bwrite).
- Map SMB bus error bits to EIO in smbus_error().
- Make the smbus driver call bus_generic_probe() and require child drivers
  such as smb(4) to create device_t's via identify routines.  Previously,
  smbus just created one anonymous device during attach, and if you had
  multiple drivers that could attach it was just random chance as to which
  driver got to probe for the sole device_t first.
- Add a mutex to the smbus(4) softc and use it in place of dummy splhigh()
  to protect the 'owner' field and perform necessary synchronization for
  smbus_request_bus() and smbus_release_bus().
- Change the bread() and bwrite() methods of alpm(4), amdpm(4), and
  viapm(4) to only perform a single transaction and not try to use a
  loop of multiple transactions for a large request.  The framing and
  commands to use for a large transaction depend on the upper-layer
  protocol (such as SSIF for IPMI over SMBus) from what I can tell, and the
  smb(4) driver never allowed bulk read/writes of more than 32-bytes
  anyway.  The other smb drivers only performed single transactions.
- Fix buffer overflows in the bread() methods of ichsmb(4), alpm(4),
  amdpm(4), amdsmb(4), intpm(4), and nfsmb(4).
- Use SMB_xxx errors in viapm(4).
- Destroy ichsmb(4)'s mutex after bus_generic_detach() to avoid problems
  from child devices making smb upcalls that would use the mutex during
  their detach methods.

MFC after:	1 week
Reviewed by:	jmg (mostly)
2006-09-11 20:52:41 +00:00

183 lines
4.1 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("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/bus.h>
#include <dev/smbus/smbconf.h>
#include <dev/smbus/smbus.h>
#include "smbus_if.h"
/*
* smbus_intr()
*/
void
smbus_intr(device_t bus, u_char devaddr, char low, char high, int error)
{
struct smbus_softc *sc = device_get_softc(bus);
/* call owner's intr routine */
mtx_lock(&sc->lock);
if (sc->owner)
SMBUS_INTR(sc->owner, devaddr, low, high, error);
mtx_unlock(&sc->lock);
}
/*
* smbus_error()
*
* Converts an smbus error to a unix error.
*/
int
smbus_error(int smb_error)
{
int error = 0;
if (smb_error == SMB_ENOERR)
return (0);
if (smb_error & (SMB_ENOTSUPP))
error = ENODEV;
else if (smb_error & (SMB_ENOACK))
error = ENXIO;
else if (smb_error & (SMB_ETIMEOUT))
error = EWOULDBLOCK;
else if (smb_error & (SMB_EBUSY))
error = EBUSY;
else if (smb_error & (SMB_EABORT | SMB_EBUSERR | SMB_ECOLLI))
error = EIO;
else
error = EINVAL;
return (error);
}
static int
smbus_poll(struct smbus_softc *sc, int how)
{
int error;
switch (how) {
case SMB_WAIT | SMB_INTR:
error = msleep(sc, &sc->lock, SMBPRI|PCATCH, "smbreq", 0);
break;
case SMB_WAIT | SMB_NOINTR:
error = msleep(sc, &sc->lock, SMBPRI, "smbreq", 0);
break;
default:
error = EWOULDBLOCK;
break;
}
return (error);
}
/*
* 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);
}