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ipmi: ssif_bmc: Add SSIF BMC driver 

The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
in-band IPMI communication with their host in management (BMC) side.

Thanks Dan for the copy_from_user() fix in the link below.

Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
Message-Id: <20221004093106.1653317-2-quan@os.amperecomputing.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
This commit is contained in:
Quan Nguyen 2022-10-04 16:31:04 +07:00 committed by Corey Minyard
parent 9abf2313ad
commit dd2bc5cc9e
4 changed files with 902 additions and 0 deletions
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10
drivers/char/ipmi/Kconfig
View File

@ -169,6 +169,16 @@ config ASPEED_BT_IPMI_BMC
found on Aspeed SOCs (AST2400 and AST2500). The driver
implements the BMC side of the BT interface.
config SSIF_IPMI_BMC
tristate "SSIF IPMI BMC driver"
depends on I2C && I2C_SLAVE
help
This enables the IPMI SMBus system interface (SSIF) at the
management (BMC) side.
The driver implements the BMC side of the SMBus system
interface (SSIF).
config IPMB_DEVICE_INTERFACE
tristate 'IPMB Interface handler'
depends on I2C

1
drivers/char/ipmi/Makefile
View File

@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o

873
drivers/char/ipmi/ssif_bmc.c Normal file
View File

@ -0,0 +1,873 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* The driver for BMC side of SSIF interface
*
* Copyright (c) 2022, Ampere Computing LLC
*
*/
#include <linux/i2c.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/ipmi_ssif_bmc.h>
#define DEVICE_NAME "ipmi-ssif-host"
#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
/* A standard SMBus Transaction is limited to 32 data bytes */
#define MAX_PAYLOAD_PER_TRANSACTION 32
/* Transaction includes the address, the command, the length and the PEC byte */
#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
#define SSIF_IPMI_SINGLEPART_WRITE 0x2
#define SSIF_IPMI_SINGLEPART_READ 0x3
#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
#define SSIF_IPMI_MULTIPART_READ_START 0x3
#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
/*
* IPMI 2.0 Spec, section 12.7 SSIF Timing,
* Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
* Recover ssif_bmc from busy state if it takes up to 500ms
*/
#define RESPONSE_TIMEOUT 500 /* ms */
struct ssif_part_buffer {
u8 address;
u8 smbus_cmd;
u8 length;
u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
u8 pec;
u8 index;
};
/*
* SSIF internal states:
* SSIF_READY 0x00 : Ready state
* SSIF_START 0x01 : Start smbus transaction
* SSIF_SMBUS_CMD 0x02 : Received SMBus command
* SSIF_REQ_RECVING 0x03 : Receiving request
* SSIF_RES_SENDING 0x04 : Sending response
* SSIF_ABORTING 0x05 : Aborting state
*/
enum ssif_state {
SSIF_READY,
SSIF_START,
SSIF_SMBUS_CMD,
SSIF_REQ_RECVING,
SSIF_RES_SENDING,
SSIF_ABORTING,
SSIF_STATE_MAX
};
struct ssif_bmc_ctx {
struct i2c_client *client;
struct miscdevice miscdev;
int msg_idx;
bool pec_support;
/* ssif bmc spinlock */
spinlock_t lock;
wait_queue_head_t wait_queue;
u8 running;
enum ssif_state state;
/* Timeout waiting for response */
struct timer_list response_timer;
bool response_timer_inited;
/* Flag to identify a Multi-part Read Transaction */
bool is_singlepart_read;
u8 nbytes_processed;
u8 remain_len;
u8 recv_len;
/* Block Number of a Multi-part Read Transaction */
u8 block_num;
bool request_available;
bool response_in_progress;
bool busy;
bool aborting;
/* Buffer for SSIF Transaction part*/
struct ssif_part_buffer part_buf;
struct ipmi_ssif_msg response;
struct ipmi_ssif_msg request;
};
static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
{
return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
}
static const char *state_to_string(enum ssif_state state)
{
switch (state) {
case SSIF_READY:
return "SSIF_READY";
case SSIF_START:
return "SSIF_START";
case SSIF_SMBUS_CMD:
return "SSIF_SMBUS_CMD";
case SSIF_REQ_RECVING:
return "SSIF_REQ_RECVING";
case SSIF_RES_SENDING:
return "SSIF_RES_SENDING";
case SSIF_ABORTING:
return "SSIF_ABORTING";
default:
return "SSIF_STATE_UNKNOWN";
}
}
/* Handle SSIF message that will be sent to user */
static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
struct ipmi_ssif_msg msg;
unsigned long flags;
ssize_t ret;
spin_lock_irqsave(&ssif_bmc->lock, flags);
while (!ssif_bmc->request_available) {
spin_unlock_irqrestore(&ssif_bmc->lock, flags);
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
ret = wait_event_interruptible(ssif_bmc->wait_queue,
ssif_bmc->request_available);
if (ret)
return ret;
spin_lock_irqsave(&ssif_bmc->lock, flags);
}
if (count < min_t(ssize_t,
sizeof_field(struct ipmi_ssif_msg, len) + ssif_bmc->request.len,
sizeof(struct ipmi_ssif_msg))) {
spin_unlock_irqrestore(&ssif_bmc->lock, flags);
ret = -EINVAL;
} else {
count = min_t(ssize_t,
sizeof_field(struct ipmi_ssif_msg, len) + ssif_bmc->request.len,
sizeof(struct ipmi_ssif_msg));
memcpy(&msg, &ssif_bmc->request, count);
ssif_bmc->request_available = false;
spin_unlock_irqrestore(&ssif_bmc->lock, flags);
ret = copy_to_user(buf, &msg, count);
}
return (ret < 0) ? ret : count;
}
/* Handle SSIF message that is written by user */
static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
loff_t *ppos)
{
struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
struct ipmi_ssif_msg msg;
unsigned long flags;
ssize_t ret;
if (count > sizeof(struct ipmi_ssif_msg))
return -EINVAL;
if (copy_from_user(&msg, buf, count))
return -EFAULT;
if (!msg.len || count < sizeof_field(struct ipmi_ssif_msg, len) + msg.len)
return -EINVAL;
spin_lock_irqsave(&ssif_bmc->lock, flags);
while (ssif_bmc->response_in_progress) {
spin_unlock_irqrestore(&ssif_bmc->lock, flags);
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
ret = wait_event_interruptible(ssif_bmc->wait_queue,
!ssif_bmc->response_in_progress);
if (ret)
return ret;
spin_lock_irqsave(&ssif_bmc->lock, flags);
}
/*
* The write must complete before the response timeout fired, otherwise
* the response is aborted and wait for next request
* Return -EINVAL if the response is aborted
*/
ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
if (ret)
goto exit;
del_timer(&ssif_bmc->response_timer);
ssif_bmc->response_timer_inited = false;
memcpy(&ssif_bmc->response, &msg, count);
ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
ssif_bmc->response_in_progress = true;
/* ssif_bmc not busy */
ssif_bmc->busy = false;
/* Clean old request buffer */
memset(&ssif_bmc->request, 0, sizeof(struct ipmi_ssif_msg));
exit:
spin_unlock_irqrestore(&ssif_bmc->lock, flags);
return (ret < 0) ? ret : count;
}
static int ssif_bmc_open(struct inode *inode, struct file *file)
{
struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
int ret = 0;
spin_lock_irq(&ssif_bmc->lock);
if (!ssif_bmc->running)
ssif_bmc->running = 1;
else
ret = -EBUSY;
spin_unlock_irq(&ssif_bmc->lock);
return ret;
}
static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
{
struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
__poll_t mask = 0;
poll_wait(file, &ssif_bmc->wait_queue, wait);
spin_lock_irq(&ssif_bmc->lock);
/* The request is available, userspace application can get the request */
if (ssif_bmc->request_available)
mask |= POLLIN;
spin_unlock_irq(&ssif_bmc->lock);
return mask;
}
static int ssif_bmc_release(struct inode *inode, struct file *file)
{
struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
spin_lock_irq(&ssif_bmc->lock);
ssif_bmc->running = 0;
spin_unlock_irq(&ssif_bmc->lock);
return 0;
}
/*
* System calls to device interface for user apps
*/
static const struct file_operations ssif_bmc_fops = {
.owner = THIS_MODULE,
.open = ssif_bmc_open,
.read = ssif_bmc_read,
.write = ssif_bmc_write,
.release = ssif_bmc_release,
.poll = ssif_bmc_poll,
};
/* Called with ssif_bmc->lock held. */
static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
{
/* Invalidate response in buffer to denote it having been sent. */
ssif_bmc->response.len = 0;
ssif_bmc->response_in_progress = false;
ssif_bmc->nbytes_processed = 0;
ssif_bmc->remain_len = 0;
ssif_bmc->busy = false;
memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
wake_up_all(&ssif_bmc->wait_queue);
}
static void response_timeout(struct timer_list *t)
{
struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
unsigned long flags;
spin_lock_irqsave(&ssif_bmc->lock, flags);
/* Do nothing if the response is in progress */
if (!ssif_bmc->response_in_progress) {
/* Recover ssif_bmc from busy */
ssif_bmc->busy = false;
ssif_bmc->response_timer_inited = false;
/* Set aborting flag */
ssif_bmc->aborting = true;
}
spin_unlock_irqrestore(&ssif_bmc->lock, flags);
}
/* Called with ssif_bmc->lock held. */
static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
{
/* set ssif_bmc to busy waiting for response */
ssif_bmc->busy = true;
/* Request message is available to process */
ssif_bmc->request_available = true;
/* Clean old response buffer */
memset(&ssif_bmc->response, 0, sizeof(struct ipmi_ssif_msg));
/* This is the new READ request.*/
wake_up_all(&ssif_bmc->wait_queue);
/* Armed timer to recover slave from busy state in case of no response */
if (!ssif_bmc->response_timer_inited) {
timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
ssif_bmc->response_timer_inited = true;
}
mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
}
static void calculate_response_part_pec(struct ssif_part_buffer *part)
{
u8 addr = part->address;
/* PEC - Start Read Address */
part->pec = i2c_smbus_pec(0, &addr, 1);
/* PEC - SSIF Command */
part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
/* PEC - Restart Write Address */
addr = addr | 0x01;
part->pec = i2c_smbus_pec(part->pec, &addr, 1);
part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
if (part->length)
part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
}
static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
{
struct ssif_part_buffer *part = &ssif_bmc->part_buf;
part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
part->length = (u8)ssif_bmc->response.len;
/* Clear the rest to 0 */
memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
}
static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
{
struct ssif_part_buffer *part = &ssif_bmc->part_buf;
u8 part_len = 0;
part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
switch (part->smbus_cmd) {
case SSIF_IPMI_MULTIPART_READ_START:
/*
* Read Start length is 32 bytes.
* Read Start transfer first 30 bytes of IPMI response
* and 2 special code 0x00, 0x01.
*/
ssif_bmc->nbytes_processed = 0;
ssif_bmc->block_num = 0;
part->length = MAX_PAYLOAD_PER_TRANSACTION;
part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
part->payload[0] = 0x00; /* Start Flag */
part->payload[1] = 0x01; /* Start Flag */
memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
break;
case SSIF_IPMI_MULTIPART_READ_MIDDLE:
/*
* IPMI READ Middle or READ End messages can carry up to 31 bytes
* IPMI data plus block number byte.
*/
if (ssif_bmc->remain_len <= MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
/*
* This is READ End message
* Return length is the remaining response data length
* plus block number
* Block number 0xFF is to indicate this is last message
*
*/
/* Clean the buffer */
memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
part->length = ssif_bmc->remain_len + 1;
part_len = ssif_bmc->remain_len;
ssif_bmc->block_num = 0xFF;
part->payload[0] = ssif_bmc->block_num;
} else {
/*
* This is READ Middle message
* Response length is the maximum SMBUS transfer length
* Block number byte is incremented
* Return length is maximum SMBUS transfer length
*/
part->length = MAX_PAYLOAD_PER_TRANSACTION;
part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
part->payload[0] = ssif_bmc->block_num;
ssif_bmc->block_num++;
}
ssif_bmc->remain_len -= part_len;
memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
part_len);
break;
default:
/* Do not expect to go to this case */
dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
__func__, part->smbus_cmd);
break;
}
ssif_bmc->nbytes_processed += part_len;
}
static bool supported_read_cmd(u8 cmd)
{
if (cmd == SSIF_IPMI_SINGLEPART_READ ||
cmd == SSIF_IPMI_MULTIPART_READ_START ||
cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
return true;
return false;
}
static bool supported_write_cmd(u8 cmd)
{
if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
cmd == SSIF_IPMI_MULTIPART_WRITE_END)
return true;
return false;
}
/* Process the IPMI response that will be read by master */
static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
{
struct ssif_part_buffer *part = &ssif_bmc->part_buf;
/* msg_idx start from 0 */
if (part->index < part->length)
*val = part->payload[part->index];
else if (part->index == part->length && ssif_bmc->pec_support)
*val = part->pec;
else
*val = 0;
part->index++;
}
static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
{
/*
* The msg_idx must be 1 when first enter SSIF_REQ_RECVING state
* And it would never exceeded 36 bytes included the 32 bytes max payload +
* the address + the command + the len and the PEC.
*/
if (ssif_bmc->msg_idx < 1 || ssif_bmc->msg_idx > MAX_TRANSACTION)
return;
if (ssif_bmc->msg_idx == 1) {
ssif_bmc->part_buf.length = *val;
ssif_bmc->part_buf.index = 0;
} else {
ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
}
ssif_bmc->msg_idx++;
}
static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
{
struct ssif_part_buffer *part = &ssif_bmc->part_buf;
bool ret = true;
u8 cpec;
u8 addr;
if (part->index == part->length) {
/* PEC is not included */
ssif_bmc->pec_support = false;
ret = true;
goto exit;
}
if (part->index != part->length + 1) {
ret = false;
goto exit;
}
/* PEC is included */
ssif_bmc->pec_support = true;
part->pec = part->payload[part->length];
addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
cpec = i2c_smbus_pec(0, &addr, 1);
cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
cpec = i2c_smbus_pec(cpec, &part->length, 1);
/*
* As SMBus specification does not allow the length
* (byte count) in the Write-Block protocol to be zero.
* Therefore, it is illegal to have the last Middle
* transaction in the sequence carry 32-byte and have
* a length of ‘0’ in the End transaction.
* But some users may try to use this way and we should
* prevent ssif_bmc driver broken in this case.
*/
if (part->length)
cpec = i2c_smbus_pec(cpec, part->payload, part->length);
if (cpec != part->pec)
ret = false;
exit:
return ret;
}
static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
{
struct ssif_part_buffer *part = &ssif_bmc->part_buf;
unsigned int len;
switch (part->smbus_cmd) {
case SSIF_IPMI_SINGLEPART_WRITE:
/* save the whole part to request*/
ssif_bmc->request.len = part->length;
memcpy(ssif_bmc->request.payload, part->payload, part->length);
break;
case SSIF_IPMI_MULTIPART_WRITE_START:
ssif_bmc->request.len = 0;
fallthrough;
case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
case SSIF_IPMI_MULTIPART_WRITE_END:
len = ssif_bmc->request.len + part->length;
/* Do the bound check here, not allow the request len exceed 254 bytes */
if (len > IPMI_SSIF_PAYLOAD_MAX) {
dev_warn(&ssif_bmc->client->dev,
"Warn: Request exceeded 254 bytes, aborting");
/* Request too long, aborting */
ssif_bmc->aborting = true;
} else {
memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
part->payload, part->length);
ssif_bmc->request.len += part->length;
}
break;
default:
/* Do not expect to go to this case */
dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
__func__, part->smbus_cmd);
break;
}
}
static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
{
/* SMBUS command can vary (single or multi-part) */
ssif_bmc->part_buf.smbus_cmd = *val;
ssif_bmc->msg_idx = 1;
memset(&ssif_bmc->part_buf.payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
/*
* The response maybe not come in-time, causing host SSIF driver
* to timeout and resend a new request. In such case check for
* pending response and clear it
*/
if (ssif_bmc->response_in_progress)
complete_response(ssif_bmc);
/* This is new request, flip aborting flag if set */
if (ssif_bmc->aborting)
ssif_bmc->aborting = false;
}
}
static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
{
if (ssif_bmc->state == SSIF_READY ||
ssif_bmc->state == SSIF_START ||
ssif_bmc->state == SSIF_REQ_RECVING ||
ssif_bmc->state == SSIF_RES_SENDING) {
dev_warn(&ssif_bmc->client->dev,
"Warn: %s unexpected READ REQUESTED in state=%s\n",
__func__, state_to_string(ssif_bmc->state));
ssif_bmc->state = SSIF_ABORTING;
*val = 0;
return;
} else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
ssif_bmc->part_buf.smbus_cmd);
ssif_bmc->aborting = true;
}
if (ssif_bmc->aborting)
ssif_bmc->state = SSIF_ABORTING;
else
ssif_bmc->state = SSIF_RES_SENDING;
}
ssif_bmc->msg_idx = 0;
/* Send 0 if there is nothing to send */
if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
*val = 0;
return;
}
if (ssif_bmc->is_singlepart_read)
set_singlepart_response_buffer(ssif_bmc);
else
set_multipart_response_buffer(ssif_bmc);
calculate_response_part_pec(&ssif_bmc->part_buf);
ssif_bmc->part_buf.index = 0;
*val = ssif_bmc->part_buf.length;
}
static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
{
if (ssif_bmc->state == SSIF_READY ||
ssif_bmc->state == SSIF_START ||
ssif_bmc->state == SSIF_REQ_RECVING ||
ssif_bmc->state == SSIF_SMBUS_CMD) {
dev_warn(&ssif_bmc->client->dev,
"Warn: %s unexpected READ PROCESSED in state=%s\n",
__func__, state_to_string(ssif_bmc->state));
ssif_bmc->state = SSIF_ABORTING;
*val = 0;
return;
}
/* Send 0 if there is nothing to send */
if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
*val = 0;
return;
}
handle_read_processed(ssif_bmc, val);
}
static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
{
if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
ssif_bmc->state = SSIF_START;
} else if (ssif_bmc->state == SSIF_START ||
ssif_bmc->state == SSIF_REQ_RECVING ||
ssif_bmc->state == SSIF_RES_SENDING) {
dev_warn(&ssif_bmc->client->dev,
"Warn: %s unexpected WRITE REQUEST in state=%s\n",
__func__, state_to_string(ssif_bmc->state));
ssif_bmc->state = SSIF_ABORTING;
return;
}
ssif_bmc->msg_idx = 0;
ssif_bmc->part_buf.address = *val;
}
static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
{
if (ssif_bmc->state == SSIF_READY ||
ssif_bmc->state == SSIF_RES_SENDING) {
dev_warn(&ssif_bmc->client->dev,
"Warn: %s unexpected WRITE RECEIVED in state=%s\n",
__func__, state_to_string(ssif_bmc->state));
ssif_bmc->state = SSIF_ABORTING;
} else if (ssif_bmc->state == SSIF_START) {
ssif_bmc->state = SSIF_SMBUS_CMD;
} else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
ssif_bmc->part_buf.smbus_cmd);
ssif_bmc->aborting = true;
}
if (ssif_bmc->aborting)
ssif_bmc->state = SSIF_ABORTING;
else
ssif_bmc->state = SSIF_REQ_RECVING;
}
/* This is response sending state */
if (ssif_bmc->state == SSIF_REQ_RECVING)
handle_write_received(ssif_bmc, val);
else if (ssif_bmc->state == SSIF_SMBUS_CMD)
process_smbus_cmd(ssif_bmc, val);
}
static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
{
if (ssif_bmc->state == SSIF_READY ||
ssif_bmc->state == SSIF_START ||
ssif_bmc->state == SSIF_SMBUS_CMD ||
ssif_bmc->state == SSIF_ABORTING) {
dev_warn(&ssif_bmc->client->dev,
"Warn: %s unexpected SLAVE STOP in state=%s\n",
__func__, state_to_string(ssif_bmc->state));
ssif_bmc->state = SSIF_READY;
} else if (ssif_bmc->state == SSIF_REQ_RECVING) {
if (validate_request_part(ssif_bmc)) {
process_request_part(ssif_bmc);
if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
handle_request(ssif_bmc);
ssif_bmc->state = SSIF_READY;
} else {
/*
* A BMC that receives an invalid request drop the data for the write
* transaction and any further transactions (read or write) until
* the next valid read or write Start transaction is received
*/
dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
ssif_bmc->aborting = true;
}
} else if (ssif_bmc->state == SSIF_RES_SENDING) {
if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
/* Invalidate response buffer to denote it is sent */
complete_response(ssif_bmc);
ssif_bmc->state = SSIF_READY;
}
/* Reset message index */
ssif_bmc->msg_idx = 0;
}
/*
* Callback function to handle I2C slave events
*/
static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
{
unsigned long flags;
struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
int ret = 0;
spin_lock_irqsave(&ssif_bmc->lock, flags);
switch (event) {
case I2C_SLAVE_READ_REQUESTED:
on_read_requested_event(ssif_bmc, val);
break;
case I2C_SLAVE_WRITE_REQUESTED:
on_write_requested_event(ssif_bmc, val);
break;
case I2C_SLAVE_READ_PROCESSED:
on_read_processed_event(ssif_bmc, val);
break;
case I2C_SLAVE_WRITE_RECEIVED:
on_write_received_event(ssif_bmc, val);
break;
case I2C_SLAVE_STOP:
on_stop_event(ssif_bmc, val);
break;
default:
dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
break;
}
if (!ssif_bmc->aborting && ssif_bmc->busy)
ret = -EBUSY;
spin_unlock_irqrestore(&ssif_bmc->lock, flags);
return ret;
}
static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
struct ssif_bmc_ctx *ssif_bmc;
int ret;
ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
if (!ssif_bmc)
return -ENOMEM;
spin_lock_init(&ssif_bmc->lock);
init_waitqueue_head(&ssif_bmc->wait_queue);
ssif_bmc->request_available = false;
ssif_bmc->response_in_progress = false;
ssif_bmc->busy = false;
ssif_bmc->response_timer_inited = false;
/* Register misc device interface */
ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
ssif_bmc->miscdev.name = DEVICE_NAME;
ssif_bmc->miscdev.fops = &ssif_bmc_fops;
ssif_bmc->miscdev.parent = &client->dev;
ret = misc_register(&ssif_bmc->miscdev);
if (ret)
return ret;
ssif_bmc->client = client;
ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
/* Register I2C slave */
i2c_set_clientdata(client, ssif_bmc);
ret = i2c_slave_register(client, ssif_bmc_cb);
if (ret)
misc_deregister(&ssif_bmc->miscdev);
return ret;
}
static void ssif_bmc_remove(struct i2c_client *client)
{
struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
i2c_slave_unregister(client);
misc_deregister(&ssif_bmc->miscdev);
}
static const struct of_device_id ssif_bmc_match[] = {
{ .compatible = "ssif-bmc" },
{ },
};
MODULE_DEVICE_TABLE(of, ssif_bmc_match);
static const struct i2c_device_id ssif_bmc_id[] = {
{ DEVICE_NAME, 0 },
{ },
};
MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
static struct i2c_driver ssif_bmc_driver = {
.driver = {
.name = DEVICE_NAME,
.of_match_table = ssif_bmc_match,
},
.probe = ssif_bmc_probe,
.remove = ssif_bmc_remove,
.id_table = ssif_bmc_id,
};
module_i2c_driver(ssif_bmc_driver);
MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
MODULE_LICENSE("GPL");

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include/uapi/linux/ipmi_ssif_bmc.h Normal file
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/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note*/
/*
* Copyright (c) 2022, Ampere Computing LLC.
*/
#ifndef _UAPI_LINUX_IPMI_SSIF_BMC_H
#define _UAPI_LINUX_IPMI_SSIF_BMC_H
#include <linux/types.h>
/* Max length of ipmi ssif message included netfn and cmd field */
#define IPMI_SSIF_PAYLOAD_MAX 254
struct ipmi_ssif_msg {
unsigned int len;
__u8 payload[IPMI_SSIF_PAYLOAD_MAX];
};
#endif /* _UAPI_LINUX_IPMI_SSIF_BMC_H */