linux-imx

// SPDX-License-Identifier: GPL-2.0+

/*

 *  ipmi_bt_sm.c

 *

 *  The state machine for an Open IPMI BT sub-driver under ipmi_si.c, part

 *  of the driver architecture at http://sourceforge.net/projects/openipmi 

 *

 *  Author: Rocky Craig <first.last@hp.com>

 */

​

#define DEBUG /* So dev_dbg() is always available. */

​

#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"

​

#define BT_DEBUG_OFF    0   /* Used in production */

#define BT_DEBUG_ENABLE 1   /* Generic messages */

#define BT_DEBUG_MSG    2   /* Prints all request/response buffers */

#define BT_DEBUG_STATES 4   /* Verbose look at state changes */

/*

 * BT_DEBUG_OFF must be zero to correspond to the default uninitialized

 * value

 */

​

static int bt_debug; /* 0 == BT_DEBUG_OFF */

​

module_param(bt_debug, int, 0644);

MODULE_PARM_DESC(bt_debug, "debug bitmask, 1=enable, 2=messages, 4=states");

​

/*

 * Typical "Get BT Capabilities" values are 2-3 retries, 5-10 seconds,

 * and 64 byte buffers.  However, one HP implementation wants 255 bytes of

 * buffer (with a documented message of 160 bytes) so go for the max.

 * Since the Open IPMI architecture is single-message oriented at this

 * stage, the queue depth of BT is of no concern.

 */

​

#define BT_NORMAL_TIMEOUT   5   /* seconds */

#define BT_NORMAL_RETRY_LIMIT   2

#define BT_RESET_DELAY      6   /* seconds after warm reset */

​

/*

 * States are written in chronological order and usually cover

 * multiple rows of the state table discussion in the IPMI spec.

 */

​

enum bt_states {

    BT_STATE_IDLE = 0,  /* Order is critical in this list */

    BT_STATE_XACTION_START,

    BT_STATE_WRITE_BYTES,

    BT_STATE_WRITE_CONSUME,

    BT_STATE_READ_WAIT,

    BT_STATE_CLEAR_B2H,

    BT_STATE_READ_BYTES,

    BT_STATE_RESET1,    /* These must come last */

    BT_STATE_RESET2,

    BT_STATE_RESET3,

    BT_STATE_RESTART,

    BT_STATE_PRINTME,

    BT_STATE_LONG_BUSY  /* BT doesn't get hosed :-) */

};

​

/*

 * Macros seen at the end of state "case" blocks.  They help with legibility

 * and debugging.

 */

​

#define BT_STATE_CHANGE(X, Y) { bt->state = X; return Y; }

​

#define BT_SI_SM_RETURN(Y)   { last_printed = BT_STATE_PRINTME; return Y; }

​

struct si_sm_data {

    enum bt_states  state;

    unsigned char   seq;        /* BT sequence number */

    struct si_sm_io *io;

    unsigned char   write_data[IPMI_MAX_MSG_LENGTH + 2]; /* +2 for memcpy */

    int     write_count;

    unsigned char   read_data[IPMI_MAX_MSG_LENGTH + 2]; /* +2 for memcpy */

    int     read_count;

    int     truncated;

    long        timeout;    /* microseconds countdown */

    int     error_retries;  /* end of "common" fields */

    int     nonzero_status; /* hung BMCs stay all 0 */

    enum bt_states  complete;   /* to divert the state machine */

    long        BT_CAP_req2rsp;

    int     BT_CAP_retries; /* Recommended retries */

};

​