[deliverable/linux.git] / drivers / char / ipmi / ipmi_kcs_sm.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/module.h>
#include <linux/moduleparam.h>
#include <linux/string.h>
#include <linux/jiffies.h>
#include <linux/ipmi_msgdefs.h>		/* for completion codes */
#include "ipmi_si_sm.h"

/* kcs_debug is a bit-field
 *	KCS_DEBUG_ENABLE -	turned on for now
 *	KCS_DEBUG_MSG    -	commands and their responses
 *	KCS_DEBUG_STATES -	state machine
 */
#define KCS_DEBUG_STATES	4
#define KCS_DEBUG_MSG		2
#define	KCS_DEBUG_ENABLE	1

static int kcs_debug;
module_param(kcs_debug, int, 0644);
MODULE_PARM_DESC(kcs_debug, "debug bitmask, 1=enable, 2=messages, 4=states");

/* The states the KCS driver may be in. */
enum kcs_states {
	/* The KCS interface is currently doing nothing. */
	KCS_IDLE,

	/*
	 * 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_START_OP,

	/* We have written a write cmd to the interface. */
	KCS_WAIT_WRITE_START,

	/* We are writing bytes to the interface. */
	KCS_WAIT_WRITE,

	/*
	 * We have written the write end cmd to the interface, and
	 * still need to write the last byte.
	 */
	KCS_WAIT_WRITE_END,

	/* We are waiting to read data from the interface. */
	KCS_WAIT_READ,

	/*
	 * State to transition to the error handler, this was added to
	 * the state machine in the spec to be sure IBF was there.
	 */
	KCS_ERROR0,

	/*
	 * First stage error handler, wait for the interface to
	 * respond.
	 */
	KCS_ERROR1,

	/*
	 * The abort cmd has been written, wait for the interface to
	 * respond.
	 */
	KCS_ERROR2,

	/*
	 * We wrote some data to the interface, wait for it to switch
	 * to read mode.
	 */
	KCS_ERROR3,

	/* The hardware failed to follow the state machine. */
	KCS_HOSED
};

#define MAX_KCS_READ_SIZE IPMI_MAX_MSG_LENGTH
#define MAX_KCS_WRITE_SIZE IPMI_MAX_MSG_LENGTH

/* Timeouts in microseconds. */
#define IBF_RETRY_TIMEOUT (5*USEC_PER_SEC)
#define OBF_RETRY_TIMEOUT (5*USEC_PER_SEC)
#define MAX_ERROR_RETRIES 10
#define ERROR0_OBF_WAIT_JIFFIES (2*HZ)

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;
	unsigned long  error0_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) {
		if (kcs_debug & KCS_DEBUG_ENABLE)
			printk(KERN_DEBUG "ipmi_kcs_sm: kcs hosed: %s\n",
			       reason);
		kcs->state = KCS_HOSED;
	} else {
		kcs->error0_timeout = jiffies + ERROR0_OBF_WAIT_JIFFIES;
		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) {
			kcs->obf_timeout = OBF_RETRY_TIMEOUT;
			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)
{
	unsigned int i;

	if (size < 2)
		return IPMI_REQ_LEN_INVALID_ERR;
	if (size > MAX_KCS_WRITE_SIZE)
		return IPMI_REQ_LEN_EXCEEDED_ERR;

	if ((kcs->state != KCS_IDLE) && (kcs->state != KCS_HOSED))
		return IPMI_NOT_IN_MY_STATE_ERR;

	if (kcs_debug & KCS_DEBUG_MSG) {
		printk(KERN_DEBUG "start_kcs_transaction -");
		for (i = 0; i < size; i++)
			printk(" %02x", (unsigned char) (data [i]));
		printk("\n");
	}
	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);

	if (kcs_debug & KCS_DEBUG_STATES)
		printk(KERN_DEBUG "KCS: State = %d, %x\n", kcs->state, status);

	/* 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_STATE) {
			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);
		status = read_status(kcs);
		if (GET_STATUS_OBF(status))
			/* controller isn't responding */
			if (time_before(jiffies, kcs->error0_timeout))
				return SI_SM_CALL_WITH_TICK_DELAY;
		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)
{
}

const 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,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* ipmi_kcs_sm.c
	3	*
	4	* State machine for handling IPMI KCS interfaces.
	5	*
	6	* Author: MontaVista Software, Inc.
	7	* Corey Minyard <minyard@mvista.com>
	8	* source@mvista.com
	9	*
	10	* Copyright 2002 MontaVista Software Inc.
	11	*
	12	* This program is free software; you can redistribute it and/or modify it
	13	* under the terms of the GNU General Public License as published by the
	14	* Free Software Foundation; either version 2 of the License, or (at your
	15	* option) any later version.
	16	*
	17	*
	18	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
	19	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	20	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	21	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	22	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
	23	* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
	24	* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	25	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
	26	* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
	27	* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	28	*
	29	* You should have received a copy of the GNU General Public License along
	30	* with this program; if not, write to the Free Software Foundation, Inc.,
	31	* 675 Mass Ave, Cambridge, MA 02139, USA.
	32	*/
	33
	34	/*
	35	* This state machine is taken from the state machine in the IPMI spec,
	36	* pretty much verbatim. If you have questions about the states, see
	37	* that document.
	38	*/
	39
	40	#include <linux/kernel.h> /* For printk. */
c4edff1c CM	41	#include <linux/module.h>
c4edff1c CM	42	#include <linux/moduleparam.h>
1da177e4	43	#include <linux/string.h>
c3e7e791	44	#include <linux/jiffies.h>
1da177e4 LT	45	#include <linux/ipmi_msgdefs.h> /* for completion codes */
	46	#include "ipmi_si_sm.h"
	47
c4edff1c CM	48	/* kcs_debug is a bit-field
	49	* KCS_DEBUG_ENABLE - turned on for now
	50	* KCS_DEBUG_MSG - commands and their responses
	51	* KCS_DEBUG_STATES - state machine
	52	*/
	53	#define KCS_DEBUG_STATES 4
	54	#define KCS_DEBUG_MSG 2
	55	#define KCS_DEBUG_ENABLE 1
1da177e4	56
c4edff1c CM	57	static int kcs_debug;
	58	module_param(kcs_debug, int, 0644);
	59	MODULE_PARM_DESC(kcs_debug, "debug bitmask, 1=enable, 2=messages, 4=states");
1da177e4 LT	60
	61	/* The states the KCS driver may be in. */
	62	enum kcs_states {
c305e3d3 CM	63	/* The KCS interface is currently doing nothing. */
	64	KCS_IDLE,
	65
	66	/*
	67	* We are starting an operation. The data is in the output
	68	* buffer, but nothing has been done to the interface yet. This
	69	* was added to the state machine in the spec to wait for the
	70	* initial IBF.
	71	*/
	72	KCS_START_OP,
	73
	74	/* We have written a write cmd to the interface. */
	75	KCS_WAIT_WRITE_START,
	76
	77	/* We are writing bytes to the interface. */
	78	KCS_WAIT_WRITE,
	79
	80	/*
	81	* We have written the write end cmd to the interface, and
	82	* still need to write the last byte.
	83	*/
	84	KCS_WAIT_WRITE_END,
	85
	86	/* We are waiting to read data from the interface. */
	87	KCS_WAIT_READ,
	88
	89	/*
	90	* State to transition to the error handler, this was added to
	91	* the state machine in the spec to be sure IBF was there.
	92	*/
	93	KCS_ERROR0,
	94
	95	/*
	96	* First stage error handler, wait for the interface to
	97	* respond.
	98	*/
	99	KCS_ERROR1,
	100
	101	/*
	102	* The abort cmd has been written, wait for the interface to
	103	* respond.
	104	*/
	105	KCS_ERROR2,
	106
	107	/*
	108	* We wrote some data to the interface, wait for it to switch
	109	* to read mode.
	110	*/
	111	KCS_ERROR3,
	112
	113	/* The hardware failed to follow the state machine. */
	114	KCS_HOSED
1da177e4 LT	115	};
1da177e4 LT	116
5a1099ba CM	117	#define MAX_KCS_READ_SIZE IPMI_MAX_MSG_LENGTH
5a1099ba CM	118	#define MAX_KCS_WRITE_SIZE IPMI_MAX_MSG_LENGTH
1da177e4 LT	119
1da177e4 LT	120	/* Timeouts in microseconds. */
ccb3368c XX	121	#define IBF_RETRY_TIMEOUT (5*USEC_PER_SEC)
ccb3368c XX	122	#define OBF_RETRY_TIMEOUT (5*USEC_PER_SEC)
1da177e4	123	#define MAX_ERROR_RETRIES 10
c3e7e791	124	#define ERROR0_OBF_WAIT_JIFFIES (2*HZ)
1da177e4	125
c305e3d3	126	struct si_sm_data {
1da177e4 LT	127	enum kcs_states state;
	128	struct si_sm_io *io;
	129	unsigned char write_data[MAX_KCS_WRITE_SIZE];
	130	int write_pos;
	131	int write_count;
	132	int orig_write_count;
	133	unsigned char read_data[MAX_KCS_READ_SIZE];
	134	int read_pos;
	135	int truncated;
	136
	137	unsigned int error_retries;
	138	long ibf_timeout;
	139	long obf_timeout;
c3e7e791	140	unsigned long error0_timeout;
1da177e4 LT	141	};
	142
	143	static unsigned int init_kcs_data(struct si_sm_data *kcs,
	144	struct si_sm_io *io)
	145	{
	146	kcs->state = KCS_IDLE;
	147	kcs->io = io;
	148	kcs->write_pos = 0;
	149	kcs->write_count = 0;
	150	kcs->orig_write_count = 0;
	151	kcs->read_pos = 0;
	152	kcs->error_retries = 0;
	153	kcs->truncated = 0;
	154	kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
	155	kcs->obf_timeout = OBF_RETRY_TIMEOUT;
	156
	157	/* Reserve 2 I/O bytes. */
	158	return 2;
	159	}
	160
	161	static inline unsigned char read_status(struct si_sm_data *kcs)
	162	{
	163	return kcs->io->inputb(kcs->io, 1);
	164	}
	165
	166	static inline unsigned char read_data(struct si_sm_data *kcs)
	167	{
	168	return kcs->io->inputb(kcs->io, 0);
	169	}
	170
	171	static inline void write_cmd(struct si_sm_data *kcs, unsigned char data)
	172	{
	173	kcs->io->outputb(kcs->io, 1, data);
	174	}
	175
	176	static inline void write_data(struct si_sm_data *kcs, unsigned char data)
	177	{
	178	kcs->io->outputb(kcs->io, 0, data);
	179	}
	180
	181	/* Control codes. */
	182	#define KCS_GET_STATUS_ABORT 0x60
	183	#define KCS_WRITE_START 0x61
	184	#define KCS_WRITE_END 0x62
	185	#define KCS_READ_BYTE 0x68
	186
	187	/* Status bits. */
	188	#define GET_STATUS_STATE(status) (((status) >> 6) & 0x03)
	189	#define KCS_IDLE_STATE 0
	190	#define KCS_READ_STATE 1
	191	#define KCS_WRITE_STATE 2
	192	#define KCS_ERROR_STATE 3
	193	#define GET_STATUS_ATN(status) ((status) & 0x04)
	194	#define GET_STATUS_IBF(status) ((status) & 0x02)
	195	#define GET_STATUS_OBF(status) ((status) & 0x01)
	196
	197
	198	static inline void write_next_byte(struct si_sm_data *kcs)
	199	{
	200	write_data(kcs, kcs->write_data[kcs->write_pos]);
	201	(kcs->write_pos)++;
	202	(kcs->write_count)--;
	203	}
	204
205	static inline void start_error_recovery(struct si_sm_data kcs, char reason)
206	{
207	(kcs->error_retries)++;
208	if (kcs->error_retries > MAX_ERROR_RETRIES) {
c4edff1c	209	if (kcs_debug & KCS_DEBUG_ENABLE)
c305e3d3 CM	210	printk(KERN_DEBUG "ipmi_kcs_sm: kcs hosed: %s\n",
c305e3d3 CM	211	reason);
1da177e4 LT	212	kcs->state = KCS_HOSED;
1da177e4 LT	213	} else {
c3e7e791	214	kcs->error0_timeout = jiffies + ERROR0_OBF_WAIT_JIFFIES;
1da177e4 LT	215	kcs->state = KCS_ERROR0;
	216	}
	217	}
	218
	219	static inline void read_next_byte(struct si_sm_data *kcs)
	220	{
	221	if (kcs->read_pos >= MAX_KCS_READ_SIZE) {
	222	/* Throw the data away and mark it truncated. */
	223	read_data(kcs);
	224	kcs->truncated = 1;
	225	} else {
	226	kcs->read_data[kcs->read_pos] = read_data(kcs);
	227	(kcs->read_pos)++;
	228	}
	229	write_data(kcs, KCS_READ_BYTE);
	230	}
	231
	232	static inline int check_ibf(struct si_sm_data *kcs, unsigned char status,
	233	long time)
	234	{
	235	if (GET_STATUS_IBF(status)) {
	236	kcs->ibf_timeout -= time;
	237	if (kcs->ibf_timeout < 0) {
	238	start_error_recovery(kcs, "IBF not ready in time");
	239	kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
	240	return 1;
	241	}
	242	return 0;
	243	}
	244	kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
	245	return 1;
	246	}
	247
	248	static inline int check_obf(struct si_sm_data *kcs, unsigned char status,
	249	long time)
	250	{
8a3628d5	251	if (!GET_STATUS_OBF(status)) {
1da177e4 LT	252	kcs->obf_timeout -= time;
1da177e4 LT	253	if (kcs->obf_timeout < 0) {
eb6d78ec CM	254	kcs->obf_timeout = OBF_RETRY_TIMEOUT;
	255	start_error_recovery(kcs, "OBF not ready in time");
	256	return 1;
1da177e4 LT	257	}
	258	return 0;
	259	}
	260	kcs->obf_timeout = OBF_RETRY_TIMEOUT;
	261	return 1;
	262	}
	263
	264	static void clear_obf(struct si_sm_data *kcs, unsigned char status)
	265	{
	266	if (GET_STATUS_OBF(status))
	267	read_data(kcs);
	268	}
	269
	270	static void restart_kcs_transaction(struct si_sm_data *kcs)
	271	{
	272	kcs->write_count = kcs->orig_write_count;
	273	kcs->write_pos = 0;
	274	kcs->read_pos = 0;
	275	kcs->state = KCS_WAIT_WRITE_START;
	276	kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
	277	kcs->obf_timeout = OBF_RETRY_TIMEOUT;
	278	write_cmd(kcs, KCS_WRITE_START);
	279	}
	280
	281	static int start_kcs_transaction(struct si_sm_data kcs, unsigned char data,
	282	unsigned int size)
	283	{
c4edff1c CM	284	unsigned int i;
c4edff1c CM	285
4d7cbac7 CM	286	if (size < 2)
	287	return IPMI_REQ_LEN_INVALID_ERR;
	288	if (size > MAX_KCS_WRITE_SIZE)
	289	return IPMI_REQ_LEN_EXCEEDED_ERR;
	290
	291	if ((kcs->state != KCS_IDLE) && (kcs->state != KCS_HOSED))
	292	return IPMI_NOT_IN_MY_STATE_ERR;
	293
c4edff1c CM	294	if (kcs_debug & KCS_DEBUG_MSG) {
c4edff1c CM	295	printk(KERN_DEBUG "start_kcs_transaction -");
c305e3d3	296	for (i = 0; i < size; i++)
c4edff1c	297	printk(" %02x", (unsigned char) (data [i]));
c305e3d3	298	printk("\n");
c4edff1c	299	}
1da177e4 LT	300	kcs->error_retries = 0;
	301	memcpy(kcs->write_data, data, size);
	302	kcs->write_count = size;
	303	kcs->orig_write_count = size;
	304	kcs->write_pos = 0;
	305	kcs->read_pos = 0;
	306	kcs->state = KCS_START_OP;
	307	kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
	308	kcs->obf_timeout = OBF_RETRY_TIMEOUT;
	309	return 0;
	310	}
	311
	312	static int get_kcs_result(struct si_sm_data kcs, unsigned char data,
	313	unsigned int length)
	314	{
	315	if (length < kcs->read_pos) {
	316	kcs->read_pos = length;
	317	kcs->truncated = 1;
	318	}
	319
	320	memcpy(data, kcs->read_data, kcs->read_pos);
	321
	322	if ((length >= 3) && (kcs->read_pos < 3)) {
	323	/* Guarantee that we return at least 3 bytes, with an
	324	error in the third byte if it is too short. */
	325	data[2] = IPMI_ERR_UNSPECIFIED;
	326	kcs->read_pos = 3;
	327	}
	328	if (kcs->truncated) {
c305e3d3 CM	329	/*
	330	* Report a truncated error. We might overwrite
	331	* another error, but that's too bad, the user needs
	332	* to know it was truncated.
	333	*/
1da177e4 LT	334	data[2] = IPMI_ERR_MSG_TRUNCATED;
	335	kcs->truncated = 0;
	336	}
	337
	338	return kcs->read_pos;
	339	}
	340
c305e3d3 CM	341	/*
	342	* This implements the state machine defined in the IPMI manual, see
	343	* that for details on how this works. Divide that flowchart into
	344	* sections delimited by "Wait for IBF" and this will become clear.
	345	*/
1da177e4 LT	346	static enum si_sm_result kcs_event(struct si_sm_data *kcs, long time)
	347	{
	348	unsigned char status;
	349	unsigned char state;
	350
	351	status = read_status(kcs);
	352
c4edff1c CM	353	if (kcs_debug & KCS_DEBUG_STATES)
	354	printk(KERN_DEBUG "KCS: State = %d, %x\n", kcs->state, status);
	355
1da177e4 LT	356	/* All states wait for ibf, so just do it here. */
	357	if (!check_ibf(kcs, status, time))
	358	return SI_SM_CALL_WITH_DELAY;
	359
	360	/* Just about everything looks at the KCS state, so grab that, too. */
	361	state = GET_STATUS_STATE(status);
	362
	363	switch (kcs->state) {
	364	case KCS_IDLE:
	365	/* If there's and interrupt source, turn it off. */
	366	clear_obf(kcs, status);
	367
	368	if (GET_STATUS_ATN(status))
	369	return SI_SM_ATTN;
	370	else
	371	return SI_SM_IDLE;
	372
	373	case KCS_START_OP:
d1da96aa	374	if (state != KCS_IDLE_STATE) {
1da177e4 LT	375	start_error_recovery(kcs,
	376	"State machine not idle at start");
	377	break;
	378	}
	379
	380	clear_obf(kcs, status);
	381	write_cmd(kcs, KCS_WRITE_START);
	382	kcs->state = KCS_WAIT_WRITE_START;
	383	break;
	384
	385	case KCS_WAIT_WRITE_START:
	386	if (state != KCS_WRITE_STATE) {
	387	start_error_recovery(
	388	kcs,
	389	"Not in write state at write start");
	390	break;
	391	}
	392	read_data(kcs);
	393	if (kcs->write_count == 1) {
	394	write_cmd(kcs, KCS_WRITE_END);
	395	kcs->state = KCS_WAIT_WRITE_END;
	396	} else {
	397	write_next_byte(kcs);
	398	kcs->state = KCS_WAIT_WRITE;
	399	}
	400	break;
	401
	402	case KCS_WAIT_WRITE:
	403	if (state != KCS_WRITE_STATE) {
	404	start_error_recovery(kcs,
	405	"Not in write state for write");
	406	break;
	407	}
	408	clear_obf(kcs, status);
	409	if (kcs->write_count == 1) {
	410	write_cmd(kcs, KCS_WRITE_END);
	411	kcs->state = KCS_WAIT_WRITE_END;
	412	} else {
	413	write_next_byte(kcs);
	414	}
	415	break;
c305e3d3	416
1da177e4 LT	417	case KCS_WAIT_WRITE_END:
	418	if (state != KCS_WRITE_STATE) {
	419	start_error_recovery(kcs,
c305e3d3 CM	420	"Not in write state"
c305e3d3 CM	421	" for write end");
1da177e4 LT	422	break;
	423	}
	424	clear_obf(kcs, status);
	425	write_next_byte(kcs);
	426	kcs->state = KCS_WAIT_READ;
	427	break;
	428
	429	case KCS_WAIT_READ:
	430	if ((state != KCS_READ_STATE) && (state != KCS_IDLE_STATE)) {
	431	start_error_recovery(
	432	kcs,
	433	"Not in read or idle in read state");
	434	break;
	435	}
	436
	437	if (state == KCS_READ_STATE) {
8a3628d5	438	if (!check_obf(kcs, status, time))
1da177e4 LT	439	return SI_SM_CALL_WITH_DELAY;
	440	read_next_byte(kcs);
	441	} else {
c305e3d3 CM	442	/*
	443	* We don't implement this exactly like the state
	444	* machine in the spec. Some broken hardware
	445	* does not write the final dummy byte to the
	446	* read register. Thus obf will never go high
	447	* here. We just go straight to idle, and we
	448	* handle clearing out obf in idle state if it
	449	* happens to come in.
	450	*/
1da177e4 LT	451	clear_obf(kcs, status);
	452	kcs->orig_write_count = 0;
	453	kcs->state = KCS_IDLE;
	454	return SI_SM_TRANSACTION_COMPLETE;
	455	}
	456	break;
	457
	458	case KCS_ERROR0:
	459	clear_obf(kcs, status);
c3e7e791	460	status = read_status(kcs);
c305e3d3 CM	461	if (GET_STATUS_OBF(status))
c305e3d3 CM	462	/* controller isn't responding */
c3e7e791 CM	463	if (time_before(jiffies, kcs->error0_timeout))
c3e7e791 CM	464	return SI_SM_CALL_WITH_TICK_DELAY;
1da177e4 LT	465	write_cmd(kcs, KCS_GET_STATUS_ABORT);
	466	kcs->state = KCS_ERROR1;
	467	break;
	468
	469	case KCS_ERROR1:
	470	clear_obf(kcs, status);
	471	write_data(kcs, 0);
	472	kcs->state = KCS_ERROR2;
	473	break;
c305e3d3	474
1da177e4 LT	475	case KCS_ERROR2:
	476	if (state != KCS_READ_STATE) {
	477	start_error_recovery(kcs,
	478	"Not in read state for error2");
	479	break;
	480	}
8a3628d5	481	if (!check_obf(kcs, status, time))
1da177e4 LT	482	return SI_SM_CALL_WITH_DELAY;
	483
	484	clear_obf(kcs, status);
	485	write_data(kcs, KCS_READ_BYTE);
	486	kcs->state = KCS_ERROR3;
	487	break;
c305e3d3	488
1da177e4 LT	489	case KCS_ERROR3:
	490	if (state != KCS_IDLE_STATE) {
	491	start_error_recovery(kcs,
	492	"Not in idle state for error3");
	493	break;
	494	}
	495
8a3628d5	496	if (!check_obf(kcs, status, time))
1da177e4 LT	497	return SI_SM_CALL_WITH_DELAY;
	498
	499	clear_obf(kcs, status);
	500	if (kcs->orig_write_count) {
	501	restart_kcs_transaction(kcs);
	502	} else {
	503	kcs->state = KCS_IDLE;
	504	return SI_SM_TRANSACTION_COMPLETE;
	505	}
	506	break;
c305e3d3	507
1da177e4 LT	508	case KCS_HOSED:
	509	break;
	510	}
	511
	512	if (kcs->state == KCS_HOSED) {
	513	init_kcs_data(kcs, kcs->io);
	514	return SI_SM_HOSED;
	515	}
	516
	517	return SI_SM_CALL_WITHOUT_DELAY;
	518	}
	519
	520	static int kcs_size(void)
	521	{
	522	return sizeof(struct si_sm_data);
	523	}
	524
	525	static int kcs_detect(struct si_sm_data *kcs)
	526	{
c305e3d3 CM	527	/*
	528	* It's impossible for the KCS status register to be all 1's,
	529	* (assuming a properly functioning, self-initialized BMC)
	530	* but that's what you get from reading a bogus address, so we
	531	* test that first.
	532	*/
1da177e4 LT	533	if (read_status(kcs) == 0xff)
	534	return 1;
	535
	536	return 0;
	537	}
	538
	539	static void kcs_cleanup(struct si_sm_data *kcs)
	540	{
	541	}
	542
81d02b7f	543	const struct si_sm_handlers kcs_smi_handlers = {
1da177e4 LT	544	.init_data = init_kcs_data,
	545	.start_transaction = start_kcs_transaction,
	546	.get_result = get_kcs_result,
	547	.event = kcs_event,
	548	.detect = kcs_detect,
	549	.cleanup = kcs_cleanup,
	550	.size = kcs_size,
	551	};