1 files changed, 692 insertions, 0 deletions

diff --git a/drivers/char/ipmi/ipmi_bt_sm.c b/drivers/char/ipmi/ipmi_bt_sm.c
new file mode 100644
index 000000000..97d6856c9
--- /dev/null
+++ b/drivers/char/ipmi/ipmi_bt_sm.c
@@ -0,0 +1,692 @@
+// 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>
+ */
+
+#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 */
+};
+
+#define BT_CLR_WR_PTR	0x01	/* See IPMI 1.5 table 11.6.4 */
+#define BT_CLR_RD_PTR	0x02
+#define BT_H2B_ATN	0x04
+#define BT_B2H_ATN	0x08
+#define BT_SMS_ATN	0x10
+#define BT_OEM0		0x20
+#define BT_H_BUSY	0x40
+#define BT_B_BUSY	0x80
+
+/*
+ * Some bits are toggled on each write: write once to set it, once
+ * more to clear it; writing a zero does nothing.  To absolutely
+ * clear it, check its state and write if set.  This avoids the "get
+ * current then use as mask" scheme to modify one bit.  Note that the
+ * variable "bt" is hardcoded into these macros.
+ */
+
+#define BT_STATUS	bt->io->inputb(bt->io, 0)
+#define BT_CONTROL(x)	bt->io->outputb(bt->io, 0, x)
+
+#define BMC2HOST	bt->io->inputb(bt->io, 1)
+#define HOST2BMC(x)	bt->io->outputb(bt->io, 1, x)
+
+#define BT_INTMASK_R	bt->io->inputb(bt->io, 2)
+#define BT_INTMASK_W(x)	bt->io->outputb(bt->io, 2, x)
+
+/*
+ * Convenience routines for debugging.  These are not multi-open safe!
+ * Note the macros have hardcoded variables in them.
+ */
+
+static char *state2txt(unsigned char state)
+{
+	switch (state) {
+	case BT_STATE_IDLE:		return("IDLE");
+	case BT_STATE_XACTION_START:	return("XACTION");
+	case BT_STATE_WRITE_BYTES:	return("WR_BYTES");
+	case BT_STATE_WRITE_CONSUME:	return("WR_CONSUME");
+	case BT_STATE_READ_WAIT:	return("RD_WAIT");
+	case BT_STATE_CLEAR_B2H:	return("CLEAR_B2H");
+	case BT_STATE_READ_BYTES:	return("RD_BYTES");
+	case BT_STATE_RESET1:		return("RESET1");
+	case BT_STATE_RESET2:		return("RESET2");
+	case BT_STATE_RESET3:		return("RESET3");
+	case BT_STATE_RESTART:		return("RESTART");
+	case BT_STATE_LONG_BUSY:	return("LONG_BUSY");
+	}
+	return("BAD STATE");
+}
+#define STATE2TXT state2txt(bt->state)
+
+static char *status2txt(unsigned char status)
+{
+	/*
+	 * This cannot be called by two threads at the same time and
+	 * the buffer is always consumed immediately, so the static is
+	 * safe to use.
+	 */
+	static char buf[40];
+
+	strcpy(buf, "[ ");
+	if (status & BT_B_BUSY)
+		strcat(buf, "B_BUSY ");
+	if (status & BT_H_BUSY)
+		strcat(buf, "H_BUSY ");
+	if (status & BT_OEM0)
+		strcat(buf, "OEM0 ");
+	if (status & BT_SMS_ATN)
+		strcat(buf, "SMS ");
+	if (status & BT_B2H_ATN)
+		strcat(buf, "B2H ");
+	if (status & BT_H2B_ATN)
+		strcat(buf, "H2B ");
+	strcat(buf, "]");
+	return buf;
+}
+#define STATUS2TXT status2txt(status)
+
+/* called externally at insmod time, and internally on cleanup */
+
+static unsigned int bt_init_data(struct si_sm_data *bt, struct si_sm_io *io)
+{
+	memset(bt, 0, sizeof(struct si_sm_data));
+	if (bt->io != io) {
+		/* external: one-time only things */
+		bt->io = io;
+		bt->seq = 0;
+	}
+	bt->state = BT_STATE_IDLE;	/* start here */
+	bt->complete = BT_STATE_IDLE;	/* end here */
+	bt->BT_CAP_req2rsp = BT_NORMAL_TIMEOUT * USEC_PER_SEC;
+	bt->BT_CAP_retries = BT_NORMAL_RETRY_LIMIT;
+	return 3; /* We claim 3 bytes of space; ought to check SPMI table */
+}
+
+/* Jam a completion code (probably an error) into a response */
+
+static void force_result(struct si_sm_data *bt, unsigned char completion_code)
+{
+	bt->read_data[0] = 4;				/* # following bytes */
+	bt->read_data[1] = bt->write_data[1] | 4;	/* Odd NetFn/LUN */
+	bt->read_data[2] = bt->write_data[2];		/* seq (ignored) */
+	bt->read_data[3] = bt->write_data[3];		/* Command */
+	bt->read_data[4] = completion_code;
+	bt->read_count = 5;
+}
+
+/* The upper state machine starts here */
+
+static int bt_start_transaction(struct si_sm_data *bt,
+				unsigned char *data,
+				unsigned int size)
+{
+	unsigned int i;
+
+	if (size < 2)
+		return IPMI_REQ_LEN_INVALID_ERR;
+	if (size > IPMI_MAX_MSG_LENGTH)
+		return IPMI_REQ_LEN_EXCEEDED_ERR;
+
+	if (bt->state == BT_STATE_LONG_BUSY)
+		return IPMI_NODE_BUSY_ERR;
+
+	if (bt->state != BT_STATE_IDLE)
+		return IPMI_NOT_IN_MY_STATE_ERR;
+
+	if (bt_debug & BT_DEBUG_MSG) {
+		printk(KERN_WARNING "BT: +++++++++++++++++ New command\n");
+		printk(KERN_WARNING "BT: NetFn/LUN CMD [%d data]:", size - 2);
+		for (i = 0; i < size; i ++)
+			printk(" %02x", data[i]);
+		printk("\n");
+	}
+	bt->write_data[0] = size + 1;	/* all data plus seq byte */
+	bt->write_data[1] = *data;	/* NetFn/LUN */
+	bt->write_data[2] = bt->seq++;
+	memcpy(bt->write_data + 3, data + 1, size - 1);
+	bt->write_count = size + 2;
+	bt->error_retries = 0;
+	bt->nonzero_status = 0;
+	bt->truncated = 0;
+	bt->state = BT_STATE_XACTION_START;
+	bt->timeout = bt->BT_CAP_req2rsp;
+	force_result(bt, IPMI_ERR_UNSPECIFIED);
+	return 0;
+}
+
+/*
+ * After the upper state machine has been told SI_SM_TRANSACTION_COMPLETE
+ * it calls this.  Strip out the length and seq bytes.
+ */
+
+static int bt_get_result(struct si_sm_data *bt,
+			 unsigned char *data,
+			 unsigned int length)
+{
+	int i, msg_len;
+
+	msg_len = bt->read_count - 2;		/* account for length & seq */
+	if (msg_len < 3 || msg_len > IPMI_MAX_MSG_LENGTH) {
+		force_result(bt, IPMI_ERR_UNSPECIFIED);
+		msg_len = 3;
+	}
+	data[0] = bt->read_data[1];
+	data[1] = bt->read_data[3];
+	if (length < msg_len || bt->truncated) {
+		data[2] = IPMI_ERR_MSG_TRUNCATED;
+		msg_len = 3;
+	} else
+		memcpy(data + 2, bt->read_data + 4, msg_len - 2);
+
+	if (bt_debug & BT_DEBUG_MSG) {
+		printk(KERN_WARNING "BT: result %d bytes:", msg_len);
+		for (i = 0; i < msg_len; i++)
+			printk(" %02x", data[i]);
+		printk("\n");
+	}
+	return msg_len;
+}
+
+/* This bit's functionality is optional */
+#define BT_BMC_HWRST	0x80
+
+static void reset_flags(struct si_sm_data *bt)
+{
+	if (bt_debug)
+		printk(KERN_WARNING "IPMI BT: flag reset %s\n",
+					status2txt(BT_STATUS));
+	if (BT_STATUS & BT_H_BUSY)
+		BT_CONTROL(BT_H_BUSY);	/* force clear */
+	BT_CONTROL(BT_CLR_WR_PTR);	/* always reset */
+	BT_CONTROL(BT_SMS_ATN);		/* always clear */
+	BT_INTMASK_W(BT_BMC_HWRST);
+}
+
+/*
+ * Get rid of an unwanted/stale response.  This should only be needed for
+ * BMCs that support multiple outstanding requests.
+ */
+
+static void drain_BMC2HOST(struct si_sm_data *bt)
+{
+	int i, size;
+
+	if (!(BT_STATUS & BT_B2H_ATN)) 	/* Not signalling a response */
+		return;
+
+	BT_CONTROL(BT_H_BUSY);		/* now set */
+	BT_CONTROL(BT_B2H_ATN);		/* always clear */
+	BT_STATUS;			/* pause */
+	BT_CONTROL(BT_B2H_ATN);		/* some BMCs are stubborn */
+	BT_CONTROL(BT_CLR_RD_PTR);	/* always reset */
+	if (bt_debug)
+		printk(KERN_WARNING "IPMI BT: stale response %s; ",
+			status2txt(BT_STATUS));
+	size = BMC2HOST;
+	for (i = 0; i < size ; i++)
+		BMC2HOST;
+	BT_CONTROL(BT_H_BUSY);		/* now clear */
+	if (bt_debug)
+		printk("drained %d bytes\n", size + 1);
+}
+
+static inline void write_all_bytes(struct si_sm_data *bt)
+{
+	int i;
+
+	if (bt_debug & BT_DEBUG_MSG) {
+		printk(KERN_WARNING "BT: write %d bytes seq=0x%02X",
+			bt->write_count, bt->seq);
+		for (i = 0; i < bt->write_count; i++)
+			printk(" %02x", bt->write_data[i]);
+		printk("\n");
+	}
+	for (i = 0; i < bt->write_count; i++)
+		HOST2BMC(bt->write_data[i]);
+}
+
+static inline int read_all_bytes(struct si_sm_data *bt)
+{
+	unsigned int i;
+
+	/*
+	 * length is "framing info", minimum = 4: NetFn, Seq, Cmd, cCode.
+	 * Keep layout of first four bytes aligned with write_data[]
+	 */
+
+	bt->read_data[0] = BMC2HOST;
+	bt->read_count = bt->read_data[0];
+
+	if (bt->read_count < 4 || bt->read_count >= IPMI_MAX_MSG_LENGTH) {
+		if (bt_debug & BT_DEBUG_MSG)
+			printk(KERN_WARNING "BT: bad raw rsp len=%d\n",
+				bt->read_count);
+		bt->truncated = 1;
+		return 1;	/* let next XACTION START clean it up */
+	}
+	for (i = 1; i <= bt->read_count; i++)
+		bt->read_data[i] = BMC2HOST;
+	bt->read_count++;	/* Account internally for length byte */
+
+	if (bt_debug & BT_DEBUG_MSG) {
+		int max = bt->read_count;
+
+		printk(KERN_WARNING "BT: got %d bytes seq=0x%02X",
+			max, bt->read_data[2]);
+		if (max > 16)
+			max = 16;
+		for (i = 0; i < max; i++)
+			printk(KERN_CONT " %02x", bt->read_data[i]);
+		printk(KERN_CONT "%s\n", bt->read_count == max ? "" : " ...");
+	}
+
+	/* per the spec, the (NetFn[1], Seq[2], Cmd[3]) tuples must match */
+	if ((bt->read_data[3] == bt->write_data[3]) &&
+	    (bt->read_data[2] == bt->write_data[2]) &&
+	    ((bt->read_data[1] & 0xF8) == (bt->write_data[1] & 0xF8)))
+			return 1;
+
+	if (bt_debug & BT_DEBUG_MSG)
+		printk(KERN_WARNING "IPMI BT: bad packet: "
+		"want 0x(%02X, %02X, %02X) got (%02X, %02X, %02X)\n",
+		bt->write_data[1] | 0x04, bt->write_data[2], bt->write_data[3],
+		bt->read_data[1],  bt->read_data[2],  bt->read_data[3]);
+	return 0;
+}
+
+/* Restart if retries are left, or return an error completion code */
+
+static enum si_sm_result error_recovery(struct si_sm_data *bt,
+					unsigned char status,
+					unsigned char cCode)
+{
+	char *reason;
+
+	bt->timeout = bt->BT_CAP_req2rsp;
+
+	switch (cCode) {
+	case IPMI_TIMEOUT_ERR:
+		reason = "timeout";
+		break;
+	default:
+		reason = "internal error";
+		break;
+	}
+
+	printk(KERN_WARNING "IPMI BT: %s in %s %s ", 	/* open-ended line */
+		reason, STATE2TXT, STATUS2TXT);
+
+	/*
+	 * Per the IPMI spec, retries are based on the sequence number
+	 * known only to this module, so manage a restart here.
+	 */
+	(bt->error_retries)++;
+	if (bt->error_retries < bt->BT_CAP_retries) {
+		printk("%d retries left\n",
+			bt->BT_CAP_retries - bt->error_retries);
+		bt->state = BT_STATE_RESTART;
+		return SI_SM_CALL_WITHOUT_DELAY;
+	}
+
+	printk(KERN_WARNING "failed %d retries, sending error response\n",
+	       bt->BT_CAP_retries);
+	if (!bt->nonzero_status)
+		printk(KERN_ERR "IPMI BT: stuck, try power cycle\n");
+
+	/* this is most likely during insmod */
+	else if (bt->seq <= (unsigned char)(bt->BT_CAP_retries & 0xFF)) {
+		printk(KERN_WARNING "IPMI: BT reset (takes 5 secs)\n");
+		bt->state = BT_STATE_RESET1;
+		return SI_SM_CALL_WITHOUT_DELAY;
+	}
+
+	/*
+	 * Concoct a useful error message, set up the next state, and
+	 * be done with this sequence.
+	 */
+
+	bt->state = BT_STATE_IDLE;
+	switch (cCode) {
+	case IPMI_TIMEOUT_ERR:
+		if (status & BT_B_BUSY) {
+			cCode = IPMI_NODE_BUSY_ERR;
+			bt->state = BT_STATE_LONG_BUSY;
+		}
+		break;
+	default:
+		break;
+	}
+	force_result(bt, cCode);
+	return SI_SM_TRANSACTION_COMPLETE;
+}
+
+/* Check status and (usually) take action and change this state machine. */
+
+static enum si_sm_result bt_event(struct si_sm_data *bt, long time)
+{
+	unsigned char status;
+	static enum bt_states last_printed = BT_STATE_PRINTME;
+	int i;
+
+	status = BT_STATUS;
+	bt->nonzero_status |= status;
+	if ((bt_debug & BT_DEBUG_STATES) && (bt->state != last_printed)) {
+		printk(KERN_WARNING "BT: %s %s TO=%ld - %ld \n",
+			STATE2TXT,
+			STATUS2TXT,
+			bt->timeout,
+			time);
+		last_printed = bt->state;
+	}
+
+	/*
+	 * Commands that time out may still (eventually) provide a response.
+	 * This stale response will get in the way of a new response so remove
+	 * it if possible (hopefully during IDLE).  Even if it comes up later
+	 * it will be rejected by its (now-forgotten) seq number.
+	 */
+
+	if ((bt->state < BT_STATE_WRITE_BYTES) && (status & BT_B2H_ATN)) {
+		drain_BMC2HOST(bt);
+		BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
+	}
+
+	if ((bt->state != BT_STATE_IDLE) &&
+	    (bt->state <  BT_STATE_PRINTME)) {
+		/* check timeout */
+		bt->timeout -= time;
+		if ((bt->timeout < 0) && (bt->state < BT_STATE_RESET1))
+			return error_recovery(bt,
+					      status,
+					      IPMI_TIMEOUT_ERR);
+	}
+
+	switch (bt->state) {
+
+	/*
+	 * Idle state first checks for asynchronous messages from another
+	 * channel, then does some opportunistic housekeeping.
+	 */
+
+	case BT_STATE_IDLE:
+		if (status & BT_SMS_ATN) {
+			BT_CONTROL(BT_SMS_ATN);	/* clear it */
+			return SI_SM_ATTN;
+		}
+
+		if (status & BT_H_BUSY)		/* clear a leftover H_BUSY */
+			BT_CONTROL(BT_H_BUSY);
+
+		BT_SI_SM_RETURN(SI_SM_IDLE);
+
+	case BT_STATE_XACTION_START:
+		if (status & (BT_B_BUSY | BT_H2B_ATN))
+			BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
+		if (BT_STATUS & BT_H_BUSY)
+			BT_CONTROL(BT_H_BUSY);	/* force clear */
+		BT_STATE_CHANGE(BT_STATE_WRITE_BYTES,
+				SI_SM_CALL_WITHOUT_DELAY);
+
+	case BT_STATE_WRITE_BYTES:
+		if (status & BT_H_BUSY)
+			BT_CONTROL(BT_H_BUSY);	/* clear */
+		BT_CONTROL(BT_CLR_WR_PTR);
+		write_all_bytes(bt);
+		BT_CONTROL(BT_H2B_ATN);	/* can clear too fast to catch */
+		BT_STATE_CHANGE(BT_STATE_WRITE_CONSUME,
+				SI_SM_CALL_WITHOUT_DELAY);
+
+	case BT_STATE_WRITE_CONSUME:
+		if (status & (BT_B_BUSY | BT_H2B_ATN))
+			BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
+		BT_STATE_CHANGE(BT_STATE_READ_WAIT,
+				SI_SM_CALL_WITHOUT_DELAY);
+
+	/* Spinning hard can suppress B2H_ATN and force a timeout */
+
+	case BT_STATE_READ_WAIT:
+		if (!(status & BT_B2H_ATN))
+			BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
+		BT_CONTROL(BT_H_BUSY);		/* set */
+
+		/*
+		 * Uncached, ordered writes should just proceed serially but
+		 * some BMCs don't clear B2H_ATN with one hit.  Fast-path a
+		 * workaround without too much penalty to the general case.
+		 */
+
+		BT_CONTROL(BT_B2H_ATN);		/* clear it to ACK the BMC */
+		BT_STATE_CHANGE(BT_STATE_CLEAR_B2H,
+				SI_SM_CALL_WITHOUT_DELAY);
+
+	case BT_STATE_CLEAR_B2H:
+		if (status & BT_B2H_ATN) {
+			/* keep hitting it */
+			BT_CONTROL(BT_B2H_ATN);
+			BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
+		}
+		BT_STATE_CHANGE(BT_STATE_READ_BYTES,
+				SI_SM_CALL_WITHOUT_DELAY);
+
+	case BT_STATE_READ_BYTES:
+		if (!(status & BT_H_BUSY))
+			/* check in case of retry */
+			BT_CONTROL(BT_H_BUSY);
+		BT_CONTROL(BT_CLR_RD_PTR);	/* start of BMC2HOST buffer */
+		i = read_all_bytes(bt);		/* true == packet seq match */
+		BT_CONTROL(BT_H_BUSY);		/* NOW clear */
+		if (!i) 			/* Not my message */
+			BT_STATE_CHANGE(BT_STATE_READ_WAIT,
+					SI_SM_CALL_WITHOUT_DELAY);
+		bt->state = bt->complete;
+		return bt->state == BT_STATE_IDLE ?	/* where to next? */
+			SI_SM_TRANSACTION_COMPLETE :	/* normal */
+			SI_SM_CALL_WITHOUT_DELAY;	/* Startup magic */
+
+	case BT_STATE_LONG_BUSY:	/* For example: after FW update */
+		if (!(status & BT_B_BUSY)) {
+			reset_flags(bt);	/* next state is now IDLE */
+			bt_init_data(bt, bt->io);
+		}
+		return SI_SM_CALL_WITH_DELAY;	/* No repeat printing */
+
+	case BT_STATE_RESET1:
+		reset_flags(bt);
+		drain_BMC2HOST(bt);
+		BT_STATE_CHANGE(BT_STATE_RESET2,
+				SI_SM_CALL_WITH_DELAY);
+
+	case BT_STATE_RESET2:		/* Send a soft reset */
+		BT_CONTROL(BT_CLR_WR_PTR);
+		HOST2BMC(3);		/* number of bytes following */
+		HOST2BMC(0x18);		/* NetFn/LUN == Application, LUN 0 */
+		HOST2BMC(42);		/* Sequence number */
+		HOST2BMC(3);		/* Cmd == Soft reset */
+		BT_CONTROL(BT_H2B_ATN);
+		bt->timeout = BT_RESET_DELAY * USEC_PER_SEC;
+		BT_STATE_CHANGE(BT_STATE_RESET3,
+				SI_SM_CALL_WITH_DELAY);
+
+	case BT_STATE_RESET3:		/* Hold off everything for a bit */
+		if (bt->timeout > 0)
+			return SI_SM_CALL_WITH_DELAY;
+		drain_BMC2HOST(bt);
+		BT_STATE_CHANGE(BT_STATE_RESTART,
+				SI_SM_CALL_WITH_DELAY);
+
+	case BT_STATE_RESTART:		/* don't reset retries or seq! */
+		bt->read_count = 0;
+		bt->nonzero_status = 0;
+		bt->timeout = bt->BT_CAP_req2rsp;
+		BT_STATE_CHANGE(BT_STATE_XACTION_START,
+				SI_SM_CALL_WITH_DELAY);
+
+	default:	/* should never occur */
+		return error_recovery(bt,
+				      status,
+				      IPMI_ERR_UNSPECIFIED);
+	}
+	return SI_SM_CALL_WITH_DELAY;
+}
+
+static int bt_detect(struct si_sm_data *bt)
+{
+	unsigned char GetBT_CAP[] = { 0x18, 0x36 };
+	unsigned char BT_CAP[8];
+	enum si_sm_result smi_result;
+	int rv;
+
+	/*
+	 * It's impossible for the BT status and interrupt registers 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.  The calling routine uses negative logic.
+	 */
+
+	if ((BT_STATUS == 0xFF) && (BT_INTMASK_R == 0xFF))
+		return 1;
+	reset_flags(bt);
+
+	/*
+	 * Try getting the BT capabilities here.
+	 */
+	rv = bt_start_transaction(bt, GetBT_CAP, sizeof(GetBT_CAP));
+	if (rv) {
+		dev_warn(bt->io->dev,
+			 "Can't start capabilities transaction: %d\n", rv);
+		goto out_no_bt_cap;
+	}
+
+	smi_result = SI_SM_CALL_WITHOUT_DELAY;
+	for (;;) {
+		if (smi_result == SI_SM_CALL_WITH_DELAY ||
+		    smi_result == SI_SM_CALL_WITH_TICK_DELAY) {
+			schedule_timeout_uninterruptible(1);
+			smi_result = bt_event(bt, jiffies_to_usecs(1));
+		} else if (smi_result == SI_SM_CALL_WITHOUT_DELAY) {
+			smi_result = bt_event(bt, 0);
+		} else
+			break;
+	}
+
+	rv = bt_get_result(bt, BT_CAP, sizeof(BT_CAP));
+	bt_init_data(bt, bt->io);
+	if (rv < 8) {
+		dev_warn(bt->io->dev, "bt cap response too short: %d\n", rv);
+		goto out_no_bt_cap;
+	}
+
+	if (BT_CAP[2]) {
+		dev_warn(bt->io->dev, "Error fetching bt cap: %x\n", BT_CAP[2]);
+out_no_bt_cap:
+		dev_warn(bt->io->dev, "using default values\n");
+	} else {
+		bt->BT_CAP_req2rsp = BT_CAP[6] * USEC_PER_SEC;
+		bt->BT_CAP_retries = BT_CAP[7];
+	}
+
+	dev_info(bt->io->dev, "req2rsp=%ld secs retries=%d\n",
+		 bt->BT_CAP_req2rsp / USEC_PER_SEC, bt->BT_CAP_retries);
+
+	return 0;
+}
+
+static void bt_cleanup(struct si_sm_data *bt)
+{
+}
+
+static int bt_size(void)
+{
+	return sizeof(struct si_sm_data);
+}
+
+const struct si_sm_handlers bt_smi_handlers = {
+	.init_data		= bt_init_data,
+	.start_transaction	= bt_start_transaction,
+	.get_result		= bt_get_result,
+	.event			= bt_event,
+	.detect			= bt_detect,
+	.cleanup		= bt_cleanup,
+	.size			= bt_size,
+};