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path: root/drivers/char/ipmi/ipmi_kcs_sm.c
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Diffstat (limited to 'drivers/char/ipmi/ipmi_kcs_sm.c')
-rw-r--r--drivers/char/ipmi/ipmi_kcs_sm.c500
1 files changed, 500 insertions, 0 deletions
diff --git a/drivers/char/ipmi/ipmi_kcs_sm.c b/drivers/char/ipmi/ipmi_kcs_sm.c
new file mode 100644
index 000000000000..48cce24329be
--- /dev/null
+++ b/drivers/char/ipmi/ipmi_kcs_sm.c
@@ -0,0 +1,500 @@
+/*
+ * 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/string.h>
+#include <linux/ipmi_msgdefs.h> /* for completion codes */
+#include "ipmi_si_sm.h"
+
+#define IPMI_KCS_VERSION "v33"
+
+/* 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
+
+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;
+};
+
+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) {
+#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 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) {
+ 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)
+{
+ 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;
+}
+
+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);
+
+#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 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) {
+ 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);
+ 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)
+{
+}
+
+struct si_sm_handlers kcs_smi_handlers =
+{
+ .version = IPMI_KCS_VERSION,
+ .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,
+};
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