498 lines
13 KiB
C
498 lines
13 KiB
C
/*
|
|
* ipmi_kcs_sm.c
|
|
*
|
|
* State machine for handling IPMI KCS interfaces.
|
|
*
|
|
* Author: MontaVista Software, Inc.
|
|
* Corey Minyard <minyard@mvista.com>
|
|
* source@mvista.com
|
|
*
|
|
* Copyright 2002 MontaVista Software Inc.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the
|
|
* Free Software Foundation; either version 2 of the License, or (at your
|
|
* option) any later version.
|
|
*
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED ``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 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.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write to the Free Software Foundation, Inc.,
|
|
* 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
/*
|
|
* This state machine is taken from the state machine in the IPMI spec,
|
|
* pretty much verbatim. If you have questions about the states, see
|
|
* that document.
|
|
*/
|
|
|
|
#include <linux/kernel.h> /* For printk. */
|
|
#include <linux/string.h>
|
|
#include <linux/ipmi_msgdefs.h> /* for completion codes */
|
|
#include "ipmi_si_sm.h"
|
|
|
|
/* Set this if you want a printout of why the state machine was hosed
|
|
when it gets hosed. */
|
|
#define DEBUG_HOSED_REASON
|
|
|
|
/* Print the state machine state on entry every time. */
|
|
#undef DEBUG_STATE
|
|
|
|
/* The states the KCS driver may be in. */
|
|
enum kcs_states {
|
|
KCS_IDLE, /* The KCS interface is currently
|
|
doing nothing. */
|
|
KCS_START_OP, /* We are starting an operation. The
|
|
data is in the output buffer, but
|
|
nothing has been done to the
|
|
interface yet. This was added to
|
|
the state machine in the spec to
|
|
wait for the initial IBF. */
|
|
KCS_WAIT_WRITE_START, /* We have written a write cmd to the
|
|
interface. */
|
|
KCS_WAIT_WRITE, /* We are writing bytes to the
|
|
interface. */
|
|
KCS_WAIT_WRITE_END, /* We have written the write end cmd
|
|
to the interface, and still need to
|
|
write the last byte. */
|
|
KCS_WAIT_READ, /* We are waiting to read data from
|
|
the interface. */
|
|
KCS_ERROR0, /* State to transition to the error
|
|
handler, this was added to the
|
|
state machine in the spec to be
|
|
sure IBF was there. */
|
|
KCS_ERROR1, /* First stage error handler, wait for
|
|
the interface to respond. */
|
|
KCS_ERROR2, /* The abort cmd has been written,
|
|
wait for the interface to
|
|
respond. */
|
|
KCS_ERROR3, /* We wrote some data to the
|
|
interface, wait for it to switch to
|
|
read mode. */
|
|
KCS_HOSED /* The hardware failed to follow the
|
|
state machine. */
|
|
};
|
|
|
|
#define MAX_KCS_READ_SIZE 80
|
|
#define MAX_KCS_WRITE_SIZE 80
|
|
|
|
/* Timeouts in microseconds. */
|
|
#define IBF_RETRY_TIMEOUT 1000000
|
|
#define OBF_RETRY_TIMEOUT 1000000
|
|
#define MAX_ERROR_RETRIES 10
|
|
|
|
struct si_sm_data
|
|
{
|
|
enum kcs_states state;
|
|
struct si_sm_io *io;
|
|
unsigned char write_data[MAX_KCS_WRITE_SIZE];
|
|
int write_pos;
|
|
int write_count;
|
|
int orig_write_count;
|
|
unsigned char read_data[MAX_KCS_READ_SIZE];
|
|
int read_pos;
|
|
int truncated;
|
|
|
|
unsigned int error_retries;
|
|
long ibf_timeout;
|
|
long obf_timeout;
|
|
};
|
|
|
|
static unsigned int init_kcs_data(struct si_sm_data *kcs,
|
|
struct si_sm_io *io)
|
|
{
|
|
kcs->state = KCS_IDLE;
|
|
kcs->io = io;
|
|
kcs->write_pos = 0;
|
|
kcs->write_count = 0;
|
|
kcs->orig_write_count = 0;
|
|
kcs->read_pos = 0;
|
|
kcs->error_retries = 0;
|
|
kcs->truncated = 0;
|
|
kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
|
|
kcs->obf_timeout = OBF_RETRY_TIMEOUT;
|
|
|
|
/* Reserve 2 I/O bytes. */
|
|
return 2;
|
|
}
|
|
|
|
static inline unsigned char read_status(struct si_sm_data *kcs)
|
|
{
|
|
return kcs->io->inputb(kcs->io, 1);
|
|
}
|
|
|
|
static inline unsigned char read_data(struct si_sm_data *kcs)
|
|
{
|
|
return kcs->io->inputb(kcs->io, 0);
|
|
}
|
|
|
|
static inline void write_cmd(struct si_sm_data *kcs, unsigned char data)
|
|
{
|
|
kcs->io->outputb(kcs->io, 1, data);
|
|
}
|
|
|
|
static inline void write_data(struct si_sm_data *kcs, unsigned char data)
|
|
{
|
|
kcs->io->outputb(kcs->io, 0, data);
|
|
}
|
|
|
|
/* Control codes. */
|
|
#define KCS_GET_STATUS_ABORT 0x60
|
|
#define KCS_WRITE_START 0x61
|
|
#define KCS_WRITE_END 0x62
|
|
#define KCS_READ_BYTE 0x68
|
|
|
|
/* Status bits. */
|
|
#define GET_STATUS_STATE(status) (((status) >> 6) & 0x03)
|
|
#define KCS_IDLE_STATE 0
|
|
#define KCS_READ_STATE 1
|
|
#define KCS_WRITE_STATE 2
|
|
#define KCS_ERROR_STATE 3
|
|
#define GET_STATUS_ATN(status) ((status) & 0x04)
|
|
#define GET_STATUS_IBF(status) ((status) & 0x02)
|
|
#define GET_STATUS_OBF(status) ((status) & 0x01)
|
|
|
|
|
|
static inline void write_next_byte(struct si_sm_data *kcs)
|
|
{
|
|
write_data(kcs, kcs->write_data[kcs->write_pos]);
|
|
(kcs->write_pos)++;
|
|
(kcs->write_count)--;
|
|
}
|
|
|
|
static inline void start_error_recovery(struct si_sm_data *kcs, char *reason)
|
|
{
|
|
(kcs->error_retries)++;
|
|
if (kcs->error_retries > MAX_ERROR_RETRIES) {
|
|
#ifdef DEBUG_HOSED_REASON
|
|
printk("ipmi_kcs_sm: kcs hosed: %s\n", reason);
|
|
#endif
|
|
kcs->state = KCS_HOSED;
|
|
} else {
|
|
kcs->state = KCS_ERROR0;
|
|
}
|
|
}
|
|
|
|
static inline void read_next_byte(struct si_sm_data *kcs)
|
|
{
|
|
if (kcs->read_pos >= MAX_KCS_READ_SIZE) {
|
|
/* Throw the data away and mark it truncated. */
|
|
read_data(kcs);
|
|
kcs->truncated = 1;
|
|
} else {
|
|
kcs->read_data[kcs->read_pos] = read_data(kcs);
|
|
(kcs->read_pos)++;
|
|
}
|
|
write_data(kcs, KCS_READ_BYTE);
|
|
}
|
|
|
|
static inline int check_ibf(struct si_sm_data *kcs, unsigned char status,
|
|
long time)
|
|
{
|
|
if (GET_STATUS_IBF(status)) {
|
|
kcs->ibf_timeout -= time;
|
|
if (kcs->ibf_timeout < 0) {
|
|
start_error_recovery(kcs, "IBF not ready in time");
|
|
kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
|
|
return 1;
|
|
}
|
|
|
|
static inline int check_obf(struct si_sm_data *kcs, unsigned char status,
|
|
long time)
|
|
{
|
|
if (! GET_STATUS_OBF(status)) {
|
|
kcs->obf_timeout -= time;
|
|
if (kcs->obf_timeout < 0) {
|
|
start_error_recovery(kcs, "OBF not ready in time");
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
kcs->obf_timeout = OBF_RETRY_TIMEOUT;
|
|
return 1;
|
|
}
|
|
|
|
static void clear_obf(struct si_sm_data *kcs, unsigned char status)
|
|
{
|
|
if (GET_STATUS_OBF(status))
|
|
read_data(kcs);
|
|
}
|
|
|
|
static void restart_kcs_transaction(struct si_sm_data *kcs)
|
|
{
|
|
kcs->write_count = kcs->orig_write_count;
|
|
kcs->write_pos = 0;
|
|
kcs->read_pos = 0;
|
|
kcs->state = KCS_WAIT_WRITE_START;
|
|
kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
|
|
kcs->obf_timeout = OBF_RETRY_TIMEOUT;
|
|
write_cmd(kcs, KCS_WRITE_START);
|
|
}
|
|
|
|
static int start_kcs_transaction(struct si_sm_data *kcs, unsigned char *data,
|
|
unsigned int size)
|
|
{
|
|
if ((size < 2) || (size > MAX_KCS_WRITE_SIZE)) {
|
|
return -1;
|
|
}
|
|
|
|
if ((kcs->state != KCS_IDLE) && (kcs->state != KCS_HOSED)) {
|
|
return -2;
|
|
}
|
|
|
|
kcs->error_retries = 0;
|
|
memcpy(kcs->write_data, data, size);
|
|
kcs->write_count = size;
|
|
kcs->orig_write_count = size;
|
|
kcs->write_pos = 0;
|
|
kcs->read_pos = 0;
|
|
kcs->state = KCS_START_OP;
|
|
kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
|
|
kcs->obf_timeout = OBF_RETRY_TIMEOUT;
|
|
return 0;
|
|
}
|
|
|
|
static int get_kcs_result(struct si_sm_data *kcs, unsigned char *data,
|
|
unsigned int length)
|
|
{
|
|
if (length < kcs->read_pos) {
|
|
kcs->read_pos = length;
|
|
kcs->truncated = 1;
|
|
}
|
|
|
|
memcpy(data, kcs->read_data, kcs->read_pos);
|
|
|
|
if ((length >= 3) && (kcs->read_pos < 3)) {
|
|
/* Guarantee that we return at least 3 bytes, with an
|
|
error in the third byte if it is too short. */
|
|
data[2] = IPMI_ERR_UNSPECIFIED;
|
|
kcs->read_pos = 3;
|
|
}
|
|
if (kcs->truncated) {
|
|
/* Report a truncated error. We might overwrite
|
|
another error, but that's too bad, the user needs
|
|
to know it was truncated. */
|
|
data[2] = IPMI_ERR_MSG_TRUNCATED;
|
|
kcs->truncated = 0;
|
|
}
|
|
|
|
return kcs->read_pos;
|
|
}
|
|
|
|
/* This implements the state machine defined in the IPMI manual, see
|
|
that for details on how this works. Divide that flowchart into
|
|
sections delimited by "Wait for IBF" and this will become clear. */
|
|
static enum si_sm_result kcs_event(struct si_sm_data *kcs, long time)
|
|
{
|
|
unsigned char status;
|
|
unsigned char state;
|
|
|
|
status = read_status(kcs);
|
|
|
|
#ifdef DEBUG_STATE
|
|
printk(" State = %d, %x\n", kcs->state, status);
|
|
#endif
|
|
/* All states wait for ibf, so just do it here. */
|
|
if (!check_ibf(kcs, status, time))
|
|
return SI_SM_CALL_WITH_DELAY;
|
|
|
|
/* Just about everything looks at the KCS state, so grab that, too. */
|
|
state = GET_STATUS_STATE(status);
|
|
|
|
switch (kcs->state) {
|
|
case KCS_IDLE:
|
|
/* If there's and interrupt source, turn it off. */
|
|
clear_obf(kcs, status);
|
|
|
|
if (GET_STATUS_ATN(status))
|
|
return SI_SM_ATTN;
|
|
else
|
|
return SI_SM_IDLE;
|
|
|
|
case KCS_START_OP:
|
|
if (state != KCS_IDLE) {
|
|
start_error_recovery(kcs,
|
|
"State machine not idle at start");
|
|
break;
|
|
}
|
|
|
|
clear_obf(kcs, status);
|
|
write_cmd(kcs, KCS_WRITE_START);
|
|
kcs->state = KCS_WAIT_WRITE_START;
|
|
break;
|
|
|
|
case KCS_WAIT_WRITE_START:
|
|
if (state != KCS_WRITE_STATE) {
|
|
start_error_recovery(
|
|
kcs,
|
|
"Not in write state at write start");
|
|
break;
|
|
}
|
|
read_data(kcs);
|
|
if (kcs->write_count == 1) {
|
|
write_cmd(kcs, KCS_WRITE_END);
|
|
kcs->state = KCS_WAIT_WRITE_END;
|
|
} else {
|
|
write_next_byte(kcs);
|
|
kcs->state = KCS_WAIT_WRITE;
|
|
}
|
|
break;
|
|
|
|
case KCS_WAIT_WRITE:
|
|
if (state != KCS_WRITE_STATE) {
|
|
start_error_recovery(kcs,
|
|
"Not in write state for write");
|
|
break;
|
|
}
|
|
clear_obf(kcs, status);
|
|
if (kcs->write_count == 1) {
|
|
write_cmd(kcs, KCS_WRITE_END);
|
|
kcs->state = KCS_WAIT_WRITE_END;
|
|
} else {
|
|
write_next_byte(kcs);
|
|
}
|
|
break;
|
|
|
|
case KCS_WAIT_WRITE_END:
|
|
if (state != KCS_WRITE_STATE) {
|
|
start_error_recovery(kcs,
|
|
"Not in write state for write end");
|
|
break;
|
|
}
|
|
clear_obf(kcs, status);
|
|
write_next_byte(kcs);
|
|
kcs->state = KCS_WAIT_READ;
|
|
break;
|
|
|
|
case KCS_WAIT_READ:
|
|
if ((state != KCS_READ_STATE) && (state != KCS_IDLE_STATE)) {
|
|
start_error_recovery(
|
|
kcs,
|
|
"Not in read or idle in read state");
|
|
break;
|
|
}
|
|
|
|
if (state == KCS_READ_STATE) {
|
|
if (! check_obf(kcs, status, time))
|
|
return SI_SM_CALL_WITH_DELAY;
|
|
read_next_byte(kcs);
|
|
} else {
|
|
/* We don't implement this exactly like the state
|
|
machine in the spec. Some broken hardware
|
|
does not write the final dummy byte to the
|
|
read register. Thus obf will never go high
|
|
here. We just go straight to idle, and we
|
|
handle clearing out obf in idle state if it
|
|
happens to come in. */
|
|
clear_obf(kcs, status);
|
|
kcs->orig_write_count = 0;
|
|
kcs->state = KCS_IDLE;
|
|
return SI_SM_TRANSACTION_COMPLETE;
|
|
}
|
|
break;
|
|
|
|
case KCS_ERROR0:
|
|
clear_obf(kcs, status);
|
|
write_cmd(kcs, KCS_GET_STATUS_ABORT);
|
|
kcs->state = KCS_ERROR1;
|
|
break;
|
|
|
|
case KCS_ERROR1:
|
|
clear_obf(kcs, status);
|
|
write_data(kcs, 0);
|
|
kcs->state = KCS_ERROR2;
|
|
break;
|
|
|
|
case KCS_ERROR2:
|
|
if (state != KCS_READ_STATE) {
|
|
start_error_recovery(kcs,
|
|
"Not in read state for error2");
|
|
break;
|
|
}
|
|
if (! check_obf(kcs, status, time))
|
|
return SI_SM_CALL_WITH_DELAY;
|
|
|
|
clear_obf(kcs, status);
|
|
write_data(kcs, KCS_READ_BYTE);
|
|
kcs->state = KCS_ERROR3;
|
|
break;
|
|
|
|
case KCS_ERROR3:
|
|
if (state != KCS_IDLE_STATE) {
|
|
start_error_recovery(kcs,
|
|
"Not in idle state for error3");
|
|
break;
|
|
}
|
|
|
|
if (! check_obf(kcs, status, time))
|
|
return SI_SM_CALL_WITH_DELAY;
|
|
|
|
clear_obf(kcs, status);
|
|
if (kcs->orig_write_count) {
|
|
restart_kcs_transaction(kcs);
|
|
} else {
|
|
kcs->state = KCS_IDLE;
|
|
return SI_SM_TRANSACTION_COMPLETE;
|
|
}
|
|
break;
|
|
|
|
case KCS_HOSED:
|
|
break;
|
|
}
|
|
|
|
if (kcs->state == KCS_HOSED) {
|
|
init_kcs_data(kcs, kcs->io);
|
|
return SI_SM_HOSED;
|
|
}
|
|
|
|
return SI_SM_CALL_WITHOUT_DELAY;
|
|
}
|
|
|
|
static int kcs_size(void)
|
|
{
|
|
return sizeof(struct si_sm_data);
|
|
}
|
|
|
|
static int kcs_detect(struct si_sm_data *kcs)
|
|
{
|
|
/* It's impossible for the KCS status register to be all 1's,
|
|
(assuming a properly functioning, self-initialized BMC)
|
|
but that's what you get from reading a bogus address, so we
|
|
test that first. */
|
|
if (read_status(kcs) == 0xff)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void kcs_cleanup(struct si_sm_data *kcs)
|
|
{
|
|
}
|
|
|
|
struct si_sm_handlers kcs_smi_handlers =
|
|
{
|
|
.init_data = init_kcs_data,
|
|
.start_transaction = start_kcs_transaction,
|
|
.get_result = get_kcs_result,
|
|
.event = kcs_event,
|
|
.detect = kcs_detect,
|
|
.cleanup = kcs_cleanup,
|
|
.size = kcs_size,
|
|
};
|