Quelle  kcs_bmc_cdev_ipmi.c   Sprache: 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 __init kcs_bmc_ipmi_init(void)
{
 kcs_bmc_register_driver(&kcs_bmc_ipmi_driver);

 return 0;
}
module_init(kcs_bmc_ipmi_init);

static void __exit 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 ");
MODULE_AUTHOR("Andrew Jeffery ");
MODULE_DESCRIPTION("KCS BMC to handle the IPMI request from system software");