freebsd-skq/sys/dev/iicbus/iicsmb.c
Allan Jude 11ba8488b8 iicsmb: Request the bus recursively in bread()
ipmi_ssif will `smbus_request_bus()` to do multiple smbus requests
(which requests the iicbus), and then here in `bread()` we also need to
request the bus because `bread()` takes multiple transactions.
This causes deadlock as it's waiting for the bus it already has without
`IIC_RECURSIVE`.

Sponsored by:	Ampere Computing LLC
Submitted by:	Klara Inc.
Reviewed by:	imp
Differential Revision:	https://reviews.freebsd.org/D28742
2021-02-23 20:06:16 +00:00

483 lines
11 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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/smb.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),
};
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
iic2smb_error(int error)
{
switch (error) {
case IIC_NOERR:
return (SMB_ENOERR);
case IIC_EBUSERR:
return (SMB_EBUSERR);
case IIC_ENOACK:
return (SMB_ENOACK);
case IIC_ETIMEOUT:
return (SMB_ETIMEOUT);
case IIC_EBUSBSY:
return (SMB_EBUSY);
case IIC_ESTATUS:
return (SMB_EBUSERR);
case IIC_EUNDERFLOW:
return (SMB_EBUSERR);
case IIC_EOVERFLOW:
return (SMB_EBUSERR);
case IIC_ENOTSUPP:
return (SMB_ENOTSUPP);
case IIC_ENOADDR:
return (SMB_EBUSERR);
case IIC_ERESOURCE:
return (SMB_EBUSERR);
default:
return (SMB_EBUSERR);
}
}
#define TRANSFER_MSGS(dev, msgs) iicbus_transfer(dev, msgs, nitems(msgs))
static int
iicsmb_quick(device_t dev, u_char slave, int how)
{
struct iic_msg msgs[] = {
{ slave, how == SMB_QWRITE ? IIC_M_WR : IIC_M_RD, 0, NULL },
};
int error;
switch (how) {
case SMB_QWRITE:
case SMB_QREAD:
break;
default:
return (SMB_EINVAL);
}
error = TRANSFER_MSGS(dev, msgs);
return (iic2smb_error(error));
}
static int
iicsmb_sendb(device_t dev, u_char slave, char byte)
{
struct iic_msg msgs[] = {
{ slave, IIC_M_WR, 1, &byte },
};
int error;
error = TRANSFER_MSGS(dev, msgs);
return (iic2smb_error(error));
}
static int
iicsmb_recvb(device_t dev, u_char slave, char *byte)
{
struct iic_msg msgs[] = {
{ slave, IIC_M_RD, 1, byte },
};
int error;
error = TRANSFER_MSGS(dev, msgs);
return (iic2smb_error(error));
}
static int
iicsmb_writeb(device_t dev, u_char slave, char cmd, char byte)
{
uint8_t bytes[] = { cmd, byte };
struct iic_msg msgs[] = {
{ slave, IIC_M_WR, nitems(bytes), bytes },
};
int error;
error = TRANSFER_MSGS(dev, msgs);
return (iic2smb_error(error));
}
static int
iicsmb_writew(device_t dev, u_char slave, char cmd, short word)
{
uint8_t bytes[] = { cmd, word & 0xff, word >> 8 };
struct iic_msg msgs[] = {
{ slave, IIC_M_WR, nitems(bytes), bytes },
};
int error;
error = TRANSFER_MSGS(dev, msgs);
return (iic2smb_error(error));
}
static int
iicsmb_readb(device_t dev, u_char slave, char cmd, char *byte)
{
struct iic_msg msgs[] = {
{ slave, IIC_M_WR | IIC_M_NOSTOP, 1, &cmd },
{ slave, IIC_M_RD, 1, byte },
};
int error;
error = TRANSFER_MSGS(dev, msgs);
return (iic2smb_error(error));
}
static int
iicsmb_readw(device_t dev, u_char slave, char cmd, short *word)
{
uint8_t buf[2];
struct iic_msg msgs[] = {
{ slave, IIC_M_WR | IIC_M_NOSTOP, 1, &cmd },
{ slave, IIC_M_RD, nitems(buf), buf },
};
int error;
error = TRANSFER_MSGS(dev, msgs);
if (error == 0)
*word = ((uint16_t)buf[1] << 8) | buf[0];
return (iic2smb_error(error));
}
static int
iicsmb_pcall(device_t dev, u_char slave, char cmd, short sdata, short *rdata)
{
uint8_t in[3] = { cmd, sdata & 0xff, sdata >> 8 };
uint8_t out[2];
struct iic_msg msgs[] = {
{ slave, IIC_M_WR | IIC_M_NOSTOP, nitems(in), in },
{ slave, IIC_M_RD, nitems(out), out },
};
int error;
error = TRANSFER_MSGS(dev, msgs);
if (error == 0)
*rdata = ((uint16_t)out[1] << 8) | out[0];
return (iic2smb_error(error));
}
static int
iicsmb_bwrite(device_t dev, u_char slave, char cmd, u_char count, char *buf)
{
uint8_t bytes[2] = { cmd, count };
struct iic_msg msgs[] = {
{ slave, IIC_M_WR | IIC_M_NOSTOP, nitems(bytes), bytes },
{ slave, IIC_M_WR | IIC_M_NOSTART, count, buf },
};
int error;
if (count > SMB_MAXBLOCKSIZE || count == 0)
return (SMB_EINVAL);
error = TRANSFER_MSGS(dev, msgs);
return (iic2smb_error(error));
}
static int
iicsmb_bread(device_t dev, u_char slave, char cmd, u_char *count, char *buf)
{
struct iic_msg msgs[] = {
{ slave, IIC_M_WR | IIC_M_NOSTOP, 1, &cmd },
{ slave, IIC_M_RD | IIC_M_NOSTOP, 1, count },
};
struct iic_msg block_msg[] = {
{ slave, IIC_M_RD | IIC_M_NOSTART, 0, buf },
};
device_t parent = device_get_parent(dev);
int error;
/* Have to do this because the command is split in two transfers. */
error = iicbus_request_bus(parent, dev, IIC_WAIT | IIC_RECURSIVE);
if (error == 0)
error = TRANSFER_MSGS(dev, msgs);
if (error == 0) {
/*
* If the slave offers an empty or a too long reply,
* read one byte to generate the stop or abort.
*/
if (*count > SMB_MAXBLOCKSIZE || *count == 0)
block_msg[0].len = 1;
else
block_msg[0].len = *count;
error = TRANSFER_MSGS(dev, block_msg);
if (*count > SMB_MAXBLOCKSIZE || *count == 0)
error = SMB_EINVAL;
}
(void)iicbus_release_bus(parent, dev);
return (iic2smb_error(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);