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freebsd-skq/sys/dev/iicbus/iicsmb.c
dumbbell fff41eb460 iicbus: Use device_delete_children() instead of explicit child removal 
If the bus is detached and deleted by a call to device_delete_child() or
device_delete_children() on a device higher in the tree, I²C children
were already detached and deleted. So the device_t pointer stored in sc
points to freed memory: we must not try to delete it again.

By using device_delete_children(), we let subr_bus.c figure out if there
are children to take care of.

While here, make sure iicbus_detach() and iicoc_detach() call
device_delete_children() too, to be safe.

Reviewed by:	jhb, imp
Approved by:	jhb, imp
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D3926
2015-10-20 19:52:59 +00:00

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/*-
* 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("$FreeBSD$");
/*
* I2C to SMB bridge
*
* Example:
*
* smb bttv
* \ /
* smbus
* / \
* iicsmb bti2c
* |
* iicbus
* / | \
* iicbb pcf ...
* |
* lpbb
*/
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
#include <dev/smbus/smbconf.h>
#include "iicbus_if.h"
#include "smbus_if.h"
struct iicsmb_softc {
#define SMB_WAITING_ADDR 0x0
#define SMB_WAITING_LOW 0x1
#define SMB_WAITING_HIGH 0x2
#define SMB_DONE 0x3
int state;
u_char devaddr; /* slave device address */
char low; /* low byte received first */
char high; /* high byte */
struct mtx lock;
device_t smbus;
};
static int iicsmb_probe(device_t);
static int iicsmb_attach(device_t);
static int iicsmb_detach(device_t);
static void iicsmb_identify(driver_t *driver, device_t parent);
static int iicsmb_intr(device_t dev, int event, char *buf);
static int iicsmb_callback(device_t dev, int index, void *data);
static int iicsmb_quick(device_t dev, u_char slave, int how);
static int iicsmb_sendb(device_t dev, u_char slave, char byte);
static int iicsmb_recvb(device_t dev, u_char slave, char *byte);
static int iicsmb_writeb(device_t dev, u_char slave, char cmd, char byte);
static int iicsmb_writew(device_t dev, u_char slave, char cmd, short word);
static int iicsmb_readb(device_t dev, u_char slave, char cmd, char *byte);
static int iicsmb_readw(device_t dev, u_char slave, char cmd, short *word);
static int iicsmb_pcall(device_t dev, u_char slave, char cmd, short sdata, short *rdata);
static int iicsmb_bwrite(device_t dev, u_char slave, char cmd, u_char count, char *buf);
static int iicsmb_bread(device_t dev, u_char slave, char cmd, u_char *count, char *buf);
static devclass_t iicsmb_devclass;
static device_method_t iicsmb_methods[] = {
/* device interface */
DEVMETHOD(device_identify, iicsmb_identify),
DEVMETHOD(device_probe, iicsmb_probe),
DEVMETHOD(device_attach, iicsmb_attach),
DEVMETHOD(device_detach, iicsmb_detach),
/* iicbus interface */
DEVMETHOD(iicbus_intr, iicsmb_intr),
/* smbus interface */
DEVMETHOD(smbus_callback, iicsmb_callback),
DEVMETHOD(smbus_quick, iicsmb_quick),
DEVMETHOD(smbus_sendb, iicsmb_sendb),
DEVMETHOD(smbus_recvb, iicsmb_recvb),
DEVMETHOD(smbus_writeb, iicsmb_writeb),
DEVMETHOD(smbus_writew, iicsmb_writew),
DEVMETHOD(smbus_readb, iicsmb_readb),
DEVMETHOD(smbus_readw, iicsmb_readw),
DEVMETHOD(smbus_pcall, iicsmb_pcall),
DEVMETHOD(smbus_bwrite, iicsmb_bwrite),
DEVMETHOD(smbus_bread, iicsmb_bread),
DEVMETHOD_END
};
static driver_t iicsmb_driver = {
"iicsmb",
iicsmb_methods,
sizeof(struct iicsmb_softc),
};
#define IICBUS_TIMEOUT 100 /* us */
static void
iicsmb_identify(driver_t *driver, device_t parent)
{
if (device_find_child(parent, "iicsmb", -1) == NULL)
BUS_ADD_CHILD(parent, 0, "iicsmb", -1);
}
static int
iicsmb_probe(device_t dev)
{
device_set_desc(dev, "SMBus over I2C bridge");
return (BUS_PROBE_NOWILDCARD);
}
static int
iicsmb_attach(device_t dev)
{
struct iicsmb_softc *sc = (struct iicsmb_softc *)device_get_softc(dev);
mtx_init(&sc->lock, "iicsmb", NULL, MTX_DEF);
sc->smbus = device_add_child(dev, "smbus", -1);
/* probe and attach the smbus */
bus_generic_attach(dev);
return (0);
}
static int
iicsmb_detach(device_t dev)
{
struct iicsmb_softc *sc = (struct iicsmb_softc *)device_get_softc(dev);
bus_generic_detach(dev);
device_delete_children(dev);
mtx_destroy(&sc->lock);
return (0);
}
/*
* iicsmb_intr()
*
* iicbus interrupt handler
*/
static int
iicsmb_intr(device_t dev, int event, char *buf)
{
struct iicsmb_softc *sc = (struct iicsmb_softc *)device_get_softc(dev);
mtx_lock(&sc->lock);
switch (event) {
case INTR_GENERAL:
case INTR_START:
sc->state = SMB_WAITING_ADDR;
break;
case INTR_STOP:
/* call smbus intr handler */
smbus_intr(sc->smbus, sc->devaddr,
sc->low, sc->high, SMB_ENOERR);
break;
case INTR_RECEIVE:
switch (sc->state) {
case SMB_DONE:
/* XXX too much data, discard */
printf("%s: too much data from 0x%x\n", __func__,
sc->devaddr & 0xff);
goto end;
case SMB_WAITING_ADDR:
sc->devaddr = (u_char)*buf;
sc->state = SMB_WAITING_LOW;
break;
case SMB_WAITING_LOW:
sc->low = *buf;
sc->state = SMB_WAITING_HIGH;
break;
case SMB_WAITING_HIGH:
sc->high = *buf;
sc->state = SMB_DONE;
break;
}
end:
break;
case INTR_TRANSMIT:
case INTR_NOACK:
break;
case INTR_ERROR:
switch (*buf) {
case IIC_EBUSERR:
smbus_intr(sc->smbus, sc->devaddr, 0, 0, SMB_EBUSERR);
break;
default:
printf("%s unknown error 0x%x!\n", __func__,
(int)*buf);
break;
}
break;
default:
panic("%s: unknown event (%d)!", __func__, event);
}
mtx_unlock(&sc->lock);
return (0);
}
static int
iicsmb_callback(device_t dev, int index, void *data)
{
device_t parent = device_get_parent(dev);
int error = 0;
int how;
switch (index) {
case SMB_REQUEST_BUS:
/* request underlying iicbus */
how = *(int *)data;
error = iicbus_request_bus(parent, dev, how);
break;
case SMB_RELEASE_BUS:
/* release underlying iicbus */
error = iicbus_release_bus(parent, dev);
break;
default:
error = EINVAL;
}
return (error);
}
static int
iicsmb_quick(device_t dev, u_char slave, int how)
{
device_t parent = device_get_parent(dev);
int error;
switch (how) {
case SMB_QWRITE:
error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT);
break;
case SMB_QREAD:
error = iicbus_start(parent, slave | LSB, IICBUS_TIMEOUT);
break;
default:
error = EINVAL;
break;
}
if (!error)
error = iicbus_stop(parent);
return (error);
}
static int
iicsmb_sendb(device_t dev, u_char slave, char byte)
{
device_t parent = device_get_parent(dev);
int error, sent;
error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT);
if (!error) {
error = iicbus_write(parent, &byte, 1, &sent, IICBUS_TIMEOUT);
iicbus_stop(parent);
}
return (error);
}
static int
iicsmb_recvb(device_t dev, u_char slave, char *byte)
{
device_t parent = device_get_parent(dev);
int error, read;
error = iicbus_start(parent, slave | LSB, 0);
if (!error) {
error = iicbus_read(parent, byte, 1, &read, IIC_LAST_READ, IICBUS_TIMEOUT);
iicbus_stop(parent);
}
return (error);
}
static int
iicsmb_writeb(device_t dev, u_char slave, char cmd, char byte)
{
device_t parent = device_get_parent(dev);
int error, sent;
error = iicbus_start(parent, slave & ~LSB, 0);
if (!error) {
if (!(error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
error = iicbus_write(parent, &byte, 1, &sent, IICBUS_TIMEOUT);
iicbus_stop(parent);
}
return (error);
}
static int
iicsmb_writew(device_t dev, u_char slave, char cmd, short word)
{
device_t parent = device_get_parent(dev);
int error, sent;
char low = (char)(word & 0xff);
char high = (char)((word & 0xff00) >> 8);
error = iicbus_start(parent, slave & ~LSB, 0);
if (!error) {
if (!(error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
if (!(error = iicbus_write(parent, &low, 1, &sent, IICBUS_TIMEOUT)))
error = iicbus_write(parent, &high, 1, &sent, IICBUS_TIMEOUT);
iicbus_stop(parent);
}
return (error);
}
static int
iicsmb_readb(device_t dev, u_char slave, char cmd, char *byte)
{
device_t parent = device_get_parent(dev);
int error, sent, read;
if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
return (error);
if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_repeated_start(parent, slave | LSB, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_read(parent, byte, 1, &read, IIC_LAST_READ, IICBUS_TIMEOUT)))
goto error;
error:
iicbus_stop(parent);
return (error);
}
#define BUF2SHORT(low,high) \
((short)(((high) & 0xff) << 8) | (short)((low) & 0xff))
static int
iicsmb_readw(device_t dev, u_char slave, char cmd, short *word)
{
device_t parent = device_get_parent(dev);
int error, sent, read;
char buf[2];
if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
return (error);
if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_repeated_start(parent, slave | LSB, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_read(parent, buf, 2, &read, IIC_LAST_READ, IICBUS_TIMEOUT)))
goto error;
/* first, receive low, then high byte */
*word = BUF2SHORT(buf[0], buf[1]);
error:
iicbus_stop(parent);
return (error);
}
static int
iicsmb_pcall(device_t dev, u_char slave, char cmd, short sdata, short *rdata)
{
device_t parent = device_get_parent(dev);
int error, sent, read;
char buf[2];
if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
return (error);
if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
goto error;
/* first, send low, then high byte */
buf[0] = (char)(sdata & 0xff);
buf[1] = (char)((sdata & 0xff00) >> 8);
if ((error = iicbus_write(parent, buf, 2, &sent, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_repeated_start(parent, slave | LSB, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_read(parent, buf, 2, &read, IIC_LAST_READ, IICBUS_TIMEOUT)))
goto error;
/* first, receive low, then high byte */
*rdata = BUF2SHORT(buf[0], buf[1]);
error:
iicbus_stop(parent);
return (error);
}
static int
iicsmb_bwrite(device_t dev, u_char slave, char cmd, u_char count, char *buf)
{
device_t parent = device_get_parent(dev);
int error, sent;
if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_write(parent, buf, (int)count, &sent, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_stop(parent)))
goto error;
error:
return (error);
}
static int
iicsmb_bread(device_t dev, u_char slave, char cmd, u_char *count, char *buf)
{
device_t parent = device_get_parent(dev);
int error, sent, read;
if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
return (error);
if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_repeated_start(parent, slave | LSB, IICBUS_TIMEOUT)))
goto error;
if ((error = iicbus_read(parent, buf, (int)*count, &read,
IIC_LAST_READ, IICBUS_TIMEOUT)))
goto error;
*count = read;
error:
iicbus_stop(parent);
return (error);
}
DRIVER_MODULE(iicsmb, iicbus, iicsmb_driver, iicsmb_devclass, 0, 0);
DRIVER_MODULE(smbus, iicsmb, smbus_driver, smbus_devclass, 0, 0);
MODULE_DEPEND(iicsmb, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
MODULE_DEPEND(iicsmb, smbus, SMBUS_MINVER, SMBUS_PREFVER, SMBUS_MAXVER);
MODULE_VERSION(iicsmb, 1);
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