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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/char/ipmi/ipmi_kcs_sm.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/char/ipmi/ipmi_kcs_sm.c')
-rw-r--r-- | drivers/char/ipmi/ipmi_kcs_sm.c | 500 |
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, +}; |