kcs_bmc_cdev_ipmi.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2015-2018, Intel Corporation.
*/
#define pr_fmt(fmt) "kcs-bmc: " fmt
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/ipmi_bmc.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "kcs_bmc_client.h"
/* Different phases of the KCS BMC module.
* KCS_PHASE_IDLE:
* BMC should not be expecting nor sending any data.
* KCS_PHASE_WRITE_START:
* BMC is receiving a WRITE_START command from system software.
* KCS_PHASE_WRITE_DATA:
* BMC is receiving a data byte from system software.
* KCS_PHASE_WRITE_END_CMD:
* BMC is waiting a last data byte from system software.
* KCS_PHASE_WRITE_DONE:
* BMC has received the whole request from system software.
* KCS_PHASE_WAIT_READ:
* BMC is waiting the response from the upper IPMI service.
* KCS_PHASE_READ:
* BMC is transferring the response to system software.
* KCS_PHASE_ABORT_ERROR1:
* BMC is waiting error status request from system software.
* KCS_PHASE_ABORT_ERROR2:
* BMC is waiting for idle status afer error from system software.
* KCS_PHASE_ERROR:
* BMC has detected a protocol violation at the interface level.
*/
enum kcs_ipmi_phases {
KCS_PHASE_IDLE,
KCS_PHASE_WRITE_START,
KCS_PHASE_WRITE_DATA,
KCS_PHASE_WRITE_END_CMD,
KCS_PHASE_WRITE_DONE,
KCS_PHASE_WAIT_READ,
KCS_PHASE_READ,
KCS_PHASE_ABORT_ERROR1,
KCS_PHASE_ABORT_ERROR2,
KCS_PHASE_ERROR
};
/* IPMI 2.0 - Table 9-4, KCS Interface Status Codes */
enum kcs_ipmi_errors {
KCS_NO_ERROR = 0x00,
KCS_ABORTED_BY_COMMAND = 0x01,
KCS_ILLEGAL_CONTROL_CODE = 0x02,
KCS_LENGTH_ERROR = 0x06,
KCS_UNSPECIFIED_ERROR = 0xFF
};
struct kcs_bmc_ipmi {
struct list_head entry;
struct kcs_bmc_client client;
spinlock_t lock;
enum kcs_ipmi_phases phase;
enum kcs_ipmi_errors error;
wait_queue_head_t queue;
bool data_in_avail;
int data_in_idx;
u8 *data_in;
int data_out_idx;
int data_out_len;
u8 *data_out;
struct mutex mutex;
u8 *kbuffer;
struct miscdevice miscdev;
};
#define DEVICE_NAME "ipmi-kcs"
#define KCS_MSG_BUFSIZ 1000
#define KCS_ZERO_DATA 0
/* IPMI 2.0 - Table 9-1, KCS Interface Status Register Bits */
#define KCS_STATUS_STATE(state) (state << 6)
#define KCS_STATUS_STATE_MASK GENMASK(7, 6)
#define KCS_STATUS_CMD_DAT BIT(3)
#define KCS_STATUS_SMS_ATN BIT(2)
#define KCS_STATUS_IBF BIT(1)
#define KCS_STATUS_OBF BIT(0)
/* IPMI 2.0 - Table 9-2, KCS Interface State Bits */
enum kcs_states {
IDLE_STATE = 0,
READ_STATE = 1,
WRITE_STATE = 2,
ERROR_STATE = 3,
};
/* IPMI 2.0 - Table 9-3, KCS Interface Control Codes */
#define KCS_CMD_GET_STATUS_ABORT 0x60
#define KCS_CMD_WRITE_START 0x61
#define KCS_CMD_WRITE_END 0x62
#define KCS_CMD_READ_BYTE 0x68
static inline void set_state(struct kcs_bmc_ipmi *priv, u8 state)
{
kcs_bmc_update_status(priv->client.dev, KCS_STATUS_STATE_MASK, KCS_STATUS_STATE(state));
}
static void kcs_bmc_ipmi_force_abort(struct kcs_bmc_ipmi *priv)
{
set_state(priv, ERROR_STATE);
kcs_bmc_read_data(priv->client.dev);
kcs_bmc_write_data(priv->client.dev, KCS_ZERO_DATA);
priv->phase = KCS_PHASE_ERROR;
priv->data_in_avail = false;
priv->data_in_idx = 0;
}
static void kcs_bmc_ipmi_handle_data(struct kcs_bmc_ipmi *priv)
{
struct kcs_bmc_device *dev;
u8 data;
dev = priv->client.dev;
switch (priv->phase) {
case KCS_PHASE_WRITE_START:
priv->phase = KCS_PHASE_WRITE_DATA;
fallthrough;
case KCS_PHASE_WRITE_DATA:
if (priv->data_in_idx < KCS_MSG_BUFSIZ) {
set_state(priv, WRITE_STATE);
kcs_bmc_write_data(dev, KCS_ZERO_DATA);
priv->data_in[priv->data_in_idx++] = kcs_bmc_read_data(dev);
} else {
kcs_bmc_ipmi_force_abort(priv);
priv->error = KCS_LENGTH_ERROR;
}
break;
case KCS_PHASE_WRITE_END_CMD:
if (priv->data_in_idx < KCS_MSG_BUFSIZ) {
set_state(priv, READ_STATE);
priv->data_in[priv->data_in_idx++] = kcs_bmc_read_data(dev);
priv->phase = KCS_PHASE_WRITE_DONE;
priv->data_in_avail = true;
wake_up_interruptible(&priv->queue);
} else {
kcs_bmc_ipmi_force_abort(priv);
priv->error = KCS_LENGTH_ERROR;
}
break;
case KCS_PHASE_READ:
if (priv->data_out_idx == priv->data_out_len)
set_state(priv, IDLE_STATE);
data = kcs_bmc_read_data(dev);
if (data != KCS_CMD_READ_BYTE) {
set_state(priv, ERROR_STATE);
kcs_bmc_write_data(dev, KCS_ZERO_DATA);
break;
}
if (priv->data_out_idx == priv->data_out_len) {
kcs_bmc_write_data(dev, KCS_ZERO_DATA);
priv->phase = KCS_PHASE_IDLE;
break;
}
kcs_bmc_write_data(dev, priv->data_out[priv->data_out_idx++]);
break;
case KCS_PHASE_ABORT_ERROR1:
set_state(priv, READ_STATE);
kcs_bmc_read_data(dev);
kcs_bmc_write_data(dev, priv->error);
priv->phase = KCS_PHASE_ABORT_ERROR2;
break;
case KCS_PHASE_ABORT_ERROR2:
set_state(priv, IDLE_STATE);
kcs_bmc_read_data(dev);
kcs_bmc_write_data(dev, KCS_ZERO_DATA);
priv->phase = KCS_PHASE_IDLE;
break;
default:
kcs_bmc_ipmi_force_abort(priv);
break;
}
}
static void kcs_bmc_ipmi_handle_cmd(struct kcs_bmc_ipmi *priv)
{
u8 cmd;
set_state(priv, WRITE_STATE);
kcs_bmc_write_data(priv->client.dev, KCS_ZERO_DATA);
cmd = kcs_bmc_read_data(priv->client.dev);
switch (cmd) {
case KCS_CMD_WRITE_START:
priv->phase = KCS_PHASE_WRITE_START;
priv->error = KCS_NO_ERROR;
priv->data_in_avail = false;
priv->data_in_idx = 0;
break;
case KCS_CMD_WRITE_END:
if (priv->phase != KCS_PHASE_WRITE_DATA) {
kcs_bmc_ipmi_force_abort(priv);
break;
}
priv->phase = KCS_PHASE_WRITE_END_CMD;
break;
case KCS_CMD_GET_STATUS_ABORT:
if (priv->error == KCS_NO_ERROR)
priv->error = KCS_ABORTED_BY_COMMAND;
priv->phase = KCS_PHASE_ABORT_ERROR1;
priv->data_in_avail = false;
priv->data_in_idx = 0;
break;
default:
kcs_bmc_ipmi_force_abort(priv);
priv->error = KCS_ILLEGAL_CONTROL_CODE;
break;
}
}
static inline struct kcs_bmc_ipmi *client_to_kcs_bmc_ipmi(struct kcs_bmc_client *client)
{
return container_of(client, struct kcs_bmc_ipmi, client);
}
static irqreturn_t kcs_bmc_ipmi_event(struct kcs_bmc_client *client)
{
struct kcs_bmc_ipmi *priv;
u8 status;
int ret;
priv = client_to_kcs_bmc_ipmi(client);
if (!priv)
return IRQ_NONE;
spin_lock(&priv->lock);
status = kcs_bmc_read_status(client->dev);
if (status & KCS_STATUS_IBF) {
if (status & KCS_STATUS_CMD_DAT)
kcs_bmc_ipmi_handle_cmd(priv);
else
kcs_bmc_ipmi_handle_data(priv);
ret = IRQ_HANDLED;
} else {
ret = IRQ_NONE;
}
spin_unlock(&priv->lock);
return ret;
}
static const struct kcs_bmc_client_ops kcs_bmc_ipmi_client_ops = {
.event = kcs_bmc_ipmi_event,
};
static inline struct kcs_bmc_ipmi *to_kcs_bmc(struct file *filp)
{
return container_of(filp->private_data, struct kcs_bmc_ipmi, miscdev);
}
static int kcs_bmc_ipmi_open(struct inode *inode, struct file *filp)
{
struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
return kcs_bmc_enable_device(priv->client.dev, &priv->client);
}
static __poll_t kcs_bmc_ipmi_poll(struct file *filp, poll_table *wait)
{
struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
__poll_t mask = 0;
poll_wait(filp, &priv->queue, wait);
spin_lock_irq(&priv->lock);
if (priv->data_in_avail)
mask |= EPOLLIN;
spin_unlock_irq(&priv->lock);
return mask;
}
static ssize_t kcs_bmc_ipmi_read(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
bool data_avail;
size_t data_len;
ssize_t ret;
if (!(filp->f_flags & O_NONBLOCK))
wait_event_interruptible(priv->queue,
priv->data_in_avail);
mutex_lock(&priv->mutex);
spin_lock_irq(&priv->lock);
data_avail = priv->data_in_avail;
if (data_avail) {
data_len = priv->data_in_idx;
memcpy(priv->kbuffer, priv->data_in, data_len);
}
spin_unlock_irq(&priv->lock);
if (!data_avail) {
ret = -EAGAIN;
goto out_unlock;
}
if (count < data_len) {
pr_err("channel=%u with too large data : %zu\n",
priv->client.dev->channel, data_len);
spin_lock_irq(&priv->lock);
kcs_bmc_ipmi_force_abort(priv);
spin_unlock_irq(&priv->lock);
ret = -EOVERFLOW;
goto out_unlock;
}
if (copy_to_user(buf, priv->kbuffer, data_len)) {
ret = -EFAULT;
goto out_unlock;
}
ret = data_len;
spin_lock_irq(&priv->lock);
if (priv->phase == KCS_PHASE_WRITE_DONE) {
priv->phase = KCS_PHASE_WAIT_READ;
priv->data_in_avail = false;
priv->data_in_idx = 0;
} else {
ret = -EAGAIN;
}
spin_unlock_irq(&priv->lock);
out_unlock:
mutex_unlock(&priv->mutex);
return ret;
}
static ssize_t kcs_bmc_ipmi_write(struct file *filp, const char __user *buf,
size_t count, loff_t *ppos)
{
struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
ssize_t ret;
/* a minimum response size '3' : netfn + cmd + ccode */
if (count < 3 || count > KCS_MSG_BUFSIZ)
return -EINVAL;
mutex_lock(&priv->mutex);
if (copy_from_user(priv->kbuffer, buf, count)) {
ret = -EFAULT;
goto out_unlock;
}
spin_lock_irq(&priv->lock);
if (priv->phase == KCS_PHASE_WAIT_READ) {
priv->phase = KCS_PHASE_READ;
priv->data_out_idx = 1;
priv->data_out_len = count;
memcpy(priv->data_out, priv->kbuffer, count);
kcs_bmc_write_data(priv->client.dev, priv->data_out[0]);
ret = count;
} else {
ret = -EINVAL;
}
spin_unlock_irq(&priv->lock);
out_unlock:
mutex_unlock(&priv->mutex);
return ret;
}
static long kcs_bmc_ipmi_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
long ret = 0;
spin_lock_irq(&priv->lock);
switch (cmd) {
case IPMI_BMC_IOCTL_SET_SMS_ATN:
kcs_bmc_update_status(priv->client.dev, KCS_STATUS_SMS_ATN, KCS_STATUS_SMS_ATN);
break;
case IPMI_BMC_IOCTL_CLEAR_SMS_ATN:
kcs_bmc_update_status(priv->client.dev, KCS_STATUS_SMS_ATN, 0);
break;
case IPMI_BMC_IOCTL_FORCE_ABORT:
kcs_bmc_ipmi_force_abort(priv);
break;
default:
ret = -EINVAL;
break;
}
spin_unlock_irq(&priv->lock);
return ret;
}
static int kcs_bmc_ipmi_release(struct inode *inode, struct file *filp)
{
struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
kcs_bmc_ipmi_force_abort(priv);
kcs_bmc_disable_device(priv->client.dev, &priv->client);
return 0;
}
static const struct file_operations kcs_bmc_ipmi_fops = {
.owner = THIS_MODULE,
.open = kcs_bmc_ipmi_open,
.read = kcs_bmc_ipmi_read,
.write = kcs_bmc_ipmi_write,
.release = kcs_bmc_ipmi_release,
.poll = kcs_bmc_ipmi_poll,
.unlocked_ioctl = kcs_bmc_ipmi_ioctl,
};
static DEFINE_SPINLOCK(kcs_bmc_ipmi_instances_lock);
static LIST_HEAD(kcs_bmc_ipmi_instances);
static int kcs_bmc_ipmi_add_device(struct kcs_bmc_device *kcs_bmc)
{
struct kcs_bmc_ipmi *priv;
int rc;
priv = devm_kzalloc(kcs_bmc->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
spin_lock_init(&priv->lock);
mutex_init(&priv->mutex);
init_waitqueue_head(&priv->queue);
priv->client.dev = kcs_bmc;
priv->client.ops = &kcs_bmc_ipmi_client_ops;
priv->data_in = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
priv->data_out = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
priv->kbuffer = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
priv->miscdev.minor = MISC_DYNAMIC_MINOR;
priv->miscdev.name = devm_kasprintf(kcs_bmc->dev, GFP_KERNEL, "%s%u", DEVICE_NAME,
kcs_bmc->channel);
if (!priv->data_in || !priv->data_out || !priv->kbuffer || !priv->miscdev.name)
return -EINVAL;
priv->miscdev.fops = &kcs_bmc_ipmi_fops;
rc = misc_register(&priv->miscdev);
if (rc) {
dev_err(kcs_bmc->dev, "Unable to register device: %d\n", rc);
return rc;
}
spin_lock_irq(&kcs_bmc_ipmi_instances_lock);
list_add(&priv->entry, &kcs_bmc_ipmi_instances);
spin_unlock_irq(&kcs_bmc_ipmi_instances_lock);
dev_info(kcs_bmc->dev, "Initialised IPMI client for channel %d", kcs_bmc->channel);
return 0;
}
static int kcs_bmc_ipmi_remove_device(struct kcs_bmc_device *kcs_bmc)
{
struct kcs_bmc_ipmi *priv = NULL, *pos;
spin_lock_irq(&kcs_bmc_ipmi_instances_lock);
list_for_each_entry(pos, &kcs_bmc_ipmi_instances, entry) {
if (pos->client.dev == kcs_bmc) {
priv = pos;
list_del(&pos->entry);
break;
}
}
spin_unlock_irq(&kcs_bmc_ipmi_instances_lock);
if (!priv)
return -ENODEV;
misc_deregister(&priv->miscdev);
kcs_bmc_disable_device(priv->client.dev, &priv->client);
devm_kfree(kcs_bmc->dev, priv->kbuffer);
devm_kfree(kcs_bmc->dev, priv->data_out);
devm_kfree(kcs_bmc->dev, priv->data_in);
devm_kfree(kcs_bmc->dev, priv);
return 0;
}
static const struct kcs_bmc_driver_ops kcs_bmc_ipmi_driver_ops = {
.add_device = kcs_bmc_ipmi_add_device,
.remove_device = kcs_bmc_ipmi_remove_device,
};
static struct kcs_bmc_driver kcs_bmc_ipmi_driver = {
.ops = &kcs_bmc_ipmi_driver_ops,
};
static int kcs_bmc_ipmi_init(void)
{
kcs_bmc_register_driver(&kcs_bmc_ipmi_driver);
return 0;
}
module_init(kcs_bmc_ipmi_init);
static void kcs_bmc_ipmi_exit(void)
{
kcs_bmc_unregister_driver(&kcs_bmc_ipmi_driver);
}
module_exit(kcs_bmc_ipmi_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Haiyue Wang <haiyue.wang@linux.intel.com>");
MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
MODULE_DESCRIPTION("KCS BMC to handle the IPMI request from system software");