path: root/drivers/char/ipmi/ipmi_smic_sm.c

/*
 * ipmi_smic_sm.c
 *
 * The state-machine driver for an IPMI SMIC driver
 *
 * It started as a copy of Corey Minyard's driver for the KSC interface
 * and the kernel patch "mmcdev-patch-245" by HP
 *
 * modified by:	Hannes Schulz <schulz@schwaar.com>
 *		ipmi@schwaar.com
 *
 *
 * Corey Minyard's driver for the KSC interface has the following
 * copyright notice:
 *   Copyright 2002 MontaVista Software Inc.
 *
 * the kernel patch "mmcdev-patch-245" by HP has the following
 * copyright notice:
 * (c) Copyright 2001 Grant Grundler (c) Copyright
 * 2001 Hewlett-Packard Company
 *
 *
 *  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.  */

#include <linux/kernel.h> /* For printk. */
#include <linux/string.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ipmi_msgdefs.h>		/* for completion codes */
#include "ipmi_si_sm.h"

/* smic_debug is a bit-field
 *	SMIC_DEBUG_ENABLE -	turned on for now
 *	SMIC_DEBUG_MSG -	commands and their responses
 *	SMIC_DEBUG_STATES -	state machine
*/
#define SMIC_DEBUG_STATES	4
#define SMIC_DEBUG_MSG		2
#define	SMIC_DEBUG_ENABLE	1

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

enum smic_states {
	SMIC_IDLE,
	SMIC_START_OP,
	SMIC_OP_OK,
	SMIC_WRITE_START,
	SMIC_WRITE_NEXT,
	SMIC_WRITE_END,
	SMIC_WRITE2READ,
	SMIC_READ_START,
	SMIC_READ_NEXT,
	SMIC_READ_END,
	SMIC_HOSED
};

#define MAX_SMIC_READ_SIZE 80
#define MAX_SMIC_WRITE_SIZE 80
#define SMIC_MAX_ERROR_RETRIES 3

/* Timeouts in microseconds. */
#define SMIC_RETRY_TIMEOUT (2*USEC_PER_SEC)

/* SMIC Flags Register Bits */
#define SMIC_RX_DATA_READY	0x80
#define SMIC_TX_DATA_READY	0x40

/*
 * SMIC_SMI and SMIC_EVM_DATA_AVAIL are only used by
 * a few systems, and then only by Systems Management
 * Interrupts, not by the OS.  Always ignore these bits.
 *
 */
#define SMIC_SMI		0x10
#define SMIC_EVM_DATA_AVAIL	0x08
#define SMIC_SMS_DATA_AVAIL	0x04
#define SMIC_FLAG_BSY		0x01

/* SMIC Error Codes */
#define	EC_NO_ERROR		0x00
#define	EC_ABORTED		0x01
#define	EC_ILLEGAL_CONTROL	0x02
#define	EC_NO_RESPONSE		0x03
#define	EC_ILLEGAL_COMMAND	0x04
#define	EC_BUFFER_FULL		0x05

struct si_sm_data {
	enum smic_states state;
	struct si_sm_io *io;
	unsigned char	 write_data[MAX_SMIC_WRITE_SIZE];
	int		 write_pos;
	int		 write_count;
	int		 orig_write_count;
	unsigned char	 read_data[MAX_SMIC_READ_SIZE];
	int		 read_pos;
	int		 truncated;
	unsigned int	 error_retries;
	long		 smic_timeout;
};

static unsigned int init_smic_data(struct si_sm_data *smic,
				   struct si_sm_io *io)
{
	smic->state = SMIC_IDLE;
	smic->io = io;
	smic->write_pos = 0;
	smic->write_count = 0;
	smic->orig_write_count = 0;
	smic->read_pos = 0;
	smic->error_retries = 0;
	smic->truncated = 0;
	smic->smic_timeout = SMIC_RETRY_TIMEOUT;

	/* We use 3 bytes of I/O. */
	return 3;
}

static int start_smic_transaction(struct si_sm_data *smic,
				  unsigned char *data, unsigned int size)
{
	unsigned int i;

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

	if ((smic->state != SMIC_IDLE) && (smic->state != SMIC_HOSED))
		return IPMI_NOT_IN_MY_STATE_ERR;

	if (smic_debug & SMIC_DEBUG_MSG) {
		printk(KERN_DEBUG "start_smic_transaction -");
		for (i = 0; i < size; i++)
			printk(" %02x", (unsigned char) data[i]);
		printk("\n");
	}
	smic->error_retries = 0;
	memcpy(smic->write_data, data, size);
	smic->write_count = size;
	smic->orig_write_count = size;
	smic->write_pos = 0;
	smic->read_pos = 0;
	smic->state = SMIC_START_OP;
	smic->smic_timeout = SMIC_RETRY_TIMEOUT;
	return 0;
}

static int smic_get_result(struct si_sm_data *smic,
			   unsigned char *data, unsigned int length)
{
	int i;

	if (smic_debug & SMIC_DEBUG_MSG) {
		printk(KERN_DEBUG "smic_get result -");
		for (i = 0; i < smic->read_pos; i++)
			printk(" %02x", smic->read_data[i]);
		printk("\n");
	}
	if (length < smic->read_pos) {
		smic->read_pos = length;
		smic->truncated = 1;
	}
	memcpy(data, smic->read_data, smic->read_pos);

	if ((length >= 3) && (smic->read_pos < 3)) {
		data[2] = IPMI_ERR_UNSPECIFIED;
		smic->read_pos = 3;
	}
	if (smic->truncated) {
		data[2] = IPMI_ERR_MSG_TRUNCATED;
		smic->truncated = 0;
	}
	return smic->read_pos;
}

static inline unsigned char read_smic_flags(struct si_sm_data *smic)
{
	return smic->io->inputb(smic->io, 2);
}

static inline unsigned char read_smic_status(struct si_sm_data *smic)
{
	return smic->io->inputb(smic->io, 1);
}

static inline unsigned char read_smic_data(struct si_sm_data *smic)
{
	return smic->io->inputb(smic->io, 0);
}

static inline void write_smic_flags(struct si_sm_data *smic,
				    unsigned char   flags)
{
	smic->io->outputb(smic->io, 2, flags);
}

static inline void write_smic_control(struct si_sm_data *smic,
				      unsigned char   control)
{
	smic->io->outputb(smic->io, 1, control);
}

static inline void write_si_sm_data(struct si_sm_data *smic,
				    unsigned char   data)
{
	smic->io->outputb(smic->io, 0, data);
}

static inline void start_error_recovery(struct si_sm_data *smic, char *reason)
{
	(smic->error_retries)++;
	if (smic->error_retries > SMIC_MAX_ERROR_RETRIES) {
		if (smic_debug & SMIC_DEBUG_ENABLE)
			printk(KERN_WARNING
			       "ipmi_smic_drv: smic hosed: %s\n", reason);
		smic->state = SMIC_HOSED;
	} else {
		smic->write_count = smic->orig_write_count;
		smic->write_pos = 0;
		smic->read_pos = 0;
		smic->state = SMIC_START_OP;
		smic->smic_timeout = SMIC_RETRY_TIMEOUT;
	}
}

static inline void write_next_byte(struct si_sm_data *smic)
{
	write_si_sm_data(smic, smic->write_data[smic->write_pos]);
	(smic->write_pos)++;
	(smic->write_count)--;
}

static inline void read_next_byte(struct si_sm_data *smic)
{
	if (smic->read_pos >= MAX_SMIC_READ_SIZE)