patch-2.4.21 linux-2.4.21/drivers/char/ipmi/ipmi_kcs_sm.c

• Lines: 486
• Date: 2003-06-13 07:51:33.000000000 -0700
• Orig file: linux-2.4.20/drivers/char/ipmi/ipmi_kcs_sm.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.20/drivers/char/ipmi/ipmi_kcs_sm.c linux-2.4.21/drivers/char/ipmi/ipmi_kcs_sm.c
@@ -0,0 +1,485 @@
+/*
+ * 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 <asm/io.h>
+#include <asm/string.h>		/* Gets rid of memcpy warning */
+
+#include "ipmi_kcs_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
+
+#define IPMI_ERR_MSG_TRUNCATED	0xc6
+#define IPMI_ERR_UNSPECIFIED	0xff
+
+struct kcs_data
+{
+	enum kcs_states state;
+	unsigned int    port;
+	unsigned char	*addr;
+	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;
+};
+
+void init_kcs_data(struct kcs_data *kcs, unsigned int port, unsigned char *addr)
+{
+	kcs->state = KCS_IDLE;
+	kcs->port = port;
+	kcs->addr = addr;
+	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;
+}
+
+/* Remember, init_one_kcs() insured port and addr can't both be set */
+
+static inline unsigned char read_status(struct kcs_data *kcs)
+{
+        if (kcs->port)
+		return inb(kcs->port + 1);
+        else
+		return readb(kcs->addr + 1);
+}
+
+static inline unsigned char read_data(struct kcs_data *kcs)
+{
+        if (kcs->port)
+		return inb(kcs->port + 0);
+        else
+		return readb(kcs->addr + 0);
+}
+
+static inline void write_cmd(struct kcs_data *kcs, unsigned char data)
+{
+        if (kcs->port)
+		outb(data, kcs->port + 1);
+        else
+		writeb(data, kcs->addr + 1);
+}
+
+static inline void write_data(struct kcs_data *kcs, unsigned char data)
+{
+        if (kcs->port)
+		outb(data, kcs->port + 0);
+        else
+		writeb(data, kcs->addr + 0);
+}
+
+/* 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 kcs_data *kcs)
+{
+	write_data(kcs, kcs->write_data[kcs->write_pos]);
+	(kcs->write_pos)++;
+	(kcs->write_count)--;
+}
+
+static inline void start_error_recovery(struct kcs_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 kcs_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 kcs_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 kcs_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 kcs_data *kcs, unsigned char status)
+{
+	if (GET_STATUS_OBF(status))
+		read_data(kcs);
+}
+
+static void restart_kcs_transaction(struct kcs_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);
+}
+
+int start_kcs_transaction(struct kcs_data *kcs, 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;
+}
+
+int kcs_get_result(struct kcs_data *kcs, unsigned char *data, 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. */
+enum kcs_result kcs_event(struct kcs_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 KCS_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 KCS_ATTN;
+		else
+			return KCS_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 KCS_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 KCS_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 KCS_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 KCS_CALL_WITH_DELAY;
+
+		clear_obf(kcs, status);
+		if (kcs->orig_write_count) {
+			restart_kcs_transaction(kcs);
+		} else {
+			kcs->state = KCS_IDLE;
+			return KCS_TRANSACTION_COMPLETE;
+		}
+		break;
+			
+	case KCS_HOSED:
+		break;
+	}
+
+	if (kcs->state == KCS_HOSED) {
+		init_kcs_data(kcs, kcs->port, kcs->addr);
+		return KCS_SM_HOSED;
+	}
+
+	return KCS_CALL_WITHOUT_DELAY;
+}
+
+int kcs_size(void)
+{
+	return sizeof(struct kcs_data);
+}