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dcdbas.c

/*
 *  dcdbas.c: Dell Systems Management Base Driver
 *
 *  The Dell Systems Management Base Driver provides a sysfs interface for
 *  systems management software to perform System Management Interrupts (SMIs)
 *  and Host Control Actions (power cycle or power off after OS shutdown) on
 *  Dell systems.
 *
 *  See Documentation/dcdbas.txt for more information.
 *
 *  Copyright (C) 1995-2006 Dell Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License v2.0 as published by
 *  the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 */

#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mc146818rtc.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <asm/io.h>
#include <asm/semaphore.h>

#include "dcdbas.h"

#define DRIVER_NAME           "dcdbas"
#define DRIVER_VERSION        "5.6.0-3.2"
#define DRIVER_DESCRIPTION    "Dell Systems Management Base Driver"

static struct platform_device *dcdbas_pdev;

static u8 *smi_data_buf;
static dma_addr_t smi_data_buf_handle;
static unsigned long smi_data_buf_size;
static u32 smi_data_buf_phys_addr;
static DEFINE_MUTEX(smi_data_lock);

static unsigned int host_control_action;
static unsigned int host_control_smi_type;
static unsigned int host_control_on_shutdown;

/**
 * smi_data_buf_free: free SMI data buffer
 */
static void smi_data_buf_free(void)
{
      if (!smi_data_buf)
            return;

      dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
            __FUNCTION__, smi_data_buf_phys_addr, smi_data_buf_size);

      dma_free_coherent(&dcdbas_pdev->dev, smi_data_buf_size, smi_data_buf,
                    smi_data_buf_handle);
      smi_data_buf = NULL;
      smi_data_buf_handle = 0;
      smi_data_buf_phys_addr = 0;
      smi_data_buf_size = 0;
}

/**
 * smi_data_buf_realloc: grow SMI data buffer if needed
 */
static int smi_data_buf_realloc(unsigned long size)
{
      void *buf;
      dma_addr_t handle;

      if (smi_data_buf_size >= size)
            return 0;

      if (size > MAX_SMI_DATA_BUF_SIZE)
            return -EINVAL;

      /* new buffer is needed */
      buf = dma_alloc_coherent(&dcdbas_pdev->dev, size, &handle, GFP_KERNEL);
      if (!buf) {
            dev_dbg(&dcdbas_pdev->dev,
                  "%s: failed to allocate memory size %lu\n",
                  __FUNCTION__, size);
            return -ENOMEM;
      }
      /* memory zeroed by dma_alloc_coherent */

      if (smi_data_buf)
            memcpy(buf, smi_data_buf, smi_data_buf_size);

      /* free any existing buffer */
      smi_data_buf_free();

      /* set up new buffer for use */
      smi_data_buf = buf;
      smi_data_buf_handle = handle;
      smi_data_buf_phys_addr = (u32) virt_to_phys(buf);
      smi_data_buf_size = size;

      dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
            __FUNCTION__, smi_data_buf_phys_addr, smi_data_buf_size);

      return 0;
}

static ssize_t smi_data_buf_phys_addr_show(struct device *dev,
                                 struct device_attribute *attr,
                                 char *buf)
{
      return sprintf(buf, "%x\n", smi_data_buf_phys_addr);
}

static ssize_t smi_data_buf_size_show(struct device *dev,
                              struct device_attribute *attr,
                              char *buf)
{
      return sprintf(buf, "%lu\n", smi_data_buf_size);
}

static ssize_t smi_data_buf_size_store(struct device *dev,
                               struct device_attribute *attr,
                               const char *buf, size_t count)
{
      unsigned long buf_size;
      ssize_t ret;

      buf_size = simple_strtoul(buf, NULL, 10);

      /* make sure SMI data buffer is at least buf_size */
      mutex_lock(&smi_data_lock);
      ret = smi_data_buf_realloc(buf_size);
      mutex_unlock(&smi_data_lock);
      if (ret)
            return ret;

      return count;
}

static ssize_t smi_data_read(struct kobject *kobj,
                       struct bin_attribute *bin_attr,
                       char *buf, loff_t pos, size_t count)
{
      size_t max_read;
      ssize_t ret;

      mutex_lock(&smi_data_lock);

      if (pos >= smi_data_buf_size) {
            ret = 0;
            goto out;
      }

      max_read = smi_data_buf_size - pos;
      ret = min(max_read, count);
      memcpy(buf, smi_data_buf + pos, ret);
out:
      mutex_unlock(&smi_data_lock);
      return ret;
}

static ssize_t smi_data_write(struct kobject *kobj,
                        struct bin_attribute *bin_attr,
                        char *buf, loff_t pos, size_t count)
{
      ssize_t ret;

      if ((pos + count) > MAX_SMI_DATA_BUF_SIZE)
            return -EINVAL;

      mutex_lock(&smi_data_lock);

      ret = smi_data_buf_realloc(pos + count);
      if (ret)
            goto out;

      memcpy(smi_data_buf + pos, buf, count);
      ret = count;
out:
      mutex_unlock(&smi_data_lock);
      return ret;
}

static ssize_t host_control_action_show(struct device *dev,
                              struct device_attribute *attr,
                              char *buf)
{
      return sprintf(buf, "%u\n", host_control_action);
}

static ssize_t host_control_action_store(struct device *dev,
                               struct device_attribute *attr,
                               const char *buf, size_t count)
{
      ssize_t ret;

      /* make sure buffer is available for host control command */
      mutex_lock(&smi_data_lock);
      ret = smi_data_buf_realloc(sizeof(struct apm_cmd));
      mutex_unlock(&smi_data_lock);
      if (ret)
            return ret;

      host_control_action = simple_strtoul(buf, NULL, 10);
      return count;
}

static ssize_t host_control_smi_type_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
      return sprintf(buf, "%u\n", host_control_smi_type);
}

static ssize_t host_control_smi_type_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
{
      host_control_smi_type = simple_strtoul(buf, NULL, 10);
      return count;
}

static ssize_t host_control_on_shutdown_show(struct device *dev,
                                   struct device_attribute *attr,
                                   char *buf)
{
      return sprintf(buf, "%u\n", host_control_on_shutdown);
}

static ssize_t host_control_on_shutdown_store(struct device *dev,
                                    struct device_attribute *attr,
                                    const char *buf, size_t count)
{
      host_control_on_shutdown = simple_strtoul(buf, NULL, 10);
      return count;
}

/**
 * smi_request: generate SMI request
 *
 * Called with smi_data_lock.
 */
static int smi_request(struct smi_cmd *smi_cmd)
{
      cpumask_t old_mask;
      int ret = 0;

      if (smi_cmd->magic != SMI_CMD_MAGIC) {
            dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
                   __FUNCTION__);
            return -EBADR;
      }

      /* SMI requires CPU 0 */
      old_mask = current->cpus_allowed;
      set_cpus_allowed(current, cpumask_of_cpu(0));
      if (smp_processor_id() != 0) {
            dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
                  __FUNCTION__);
            ret = -EBUSY;
            goto out;
      }

      /* generate SMI */
      asm volatile (
            "outb %b0,%w1"
            : /* no output args */
            : "a" (smi_cmd->command_code),
              "d" (smi_cmd->command_address),
              "b" (smi_cmd->ebx),
              "c" (smi_cmd->ecx)
            : "memory"
      );

out:
      set_cpus_allowed(current, old_mask);
      return ret;
}

/**
 * smi_request_store:
 *
 * The valid values are:
 * 0: zero SMI data buffer
 * 1: generate calling interface SMI
 * 2: generate raw SMI
 *
 * User application writes smi_cmd to smi_data before telling driver
 * to generate SMI.
 */
static ssize_t smi_request_store(struct device *dev,
                         struct device_attribute *attr,
                         const char *buf, size_t count)
{
      struct smi_cmd *smi_cmd;
      unsigned long val = simple_strtoul(buf, NULL, 10);
      ssize_t ret;

      mutex_lock(&smi_data_lock);

      if (smi_data_buf_size < sizeof(struct smi_cmd)) {
            ret = -ENODEV;
            goto out;
      }
      smi_cmd = (struct smi_cmd *)smi_data_buf;

      switch (val) {
      case 2:
            /* Raw SMI */
            ret = smi_request(smi_cmd);
            if (!ret)
                  ret = count;
            break;
      case 1:
            /* Calling Interface SMI */
            smi_cmd->ebx = (u32) virt_to_phys(smi_cmd->command_buffer);
            ret = smi_request(smi_cmd);
            if (!ret)
                  ret = count;
            break;
      case 0:
            memset(smi_data_buf, 0, smi_data_buf_size);
            ret = count;
            break;
      default:
            ret = -EINVAL;
            break;
      }

out:
      mutex_unlock(&smi_data_lock);
      return ret;
}

/**
 * host_control_smi: generate host control SMI
 *
 * Caller must set up the host control command in smi_data_buf.
 */
static int host_control_smi(void)
{
      struct apm_cmd *apm_cmd;
      u8 *data;
      unsigned long flags;
      u32 num_ticks;
      s8 cmd_status;
      u8 index;

      apm_cmd = (struct apm_cmd *)smi_data_buf;
      apm_cmd->status = ESM_STATUS_CMD_UNSUCCESSFUL;

      switch (host_control_smi_type) {
      case HC_SMITYPE_TYPE1:
            spin_lock_irqsave(&rtc_lock, flags);
            /* write SMI data buffer physical address */
            data = (u8 *)&smi_data_buf_phys_addr;
            for (index = PE1300_CMOS_CMD_STRUCT_PTR;
                 index < (PE1300_CMOS_CMD_STRUCT_PTR + 4);
                 index++, data++) {
                  outb(index,
                       (CMOS_BASE_PORT + CMOS_PAGE2_INDEX_PORT_PIIX4));
                  outb(*data,
                       (CMOS_BASE_PORT + CMOS_PAGE2_DATA_PORT_PIIX4));
            }

            /* first set status to -1 as called by spec */
            cmd_status = ESM_STATUS_CMD_UNSUCCESSFUL;
            outb((u8) cmd_status, PCAT_APM_STATUS_PORT);

            /* generate SMM call */
            outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
            spin_unlock_irqrestore(&rtc_lock, flags);

            /* wait a few to see if it executed */
            num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
            while ((cmd_status = inb(PCAT_APM_STATUS_PORT))
                   == ESM_STATUS_CMD_UNSUCCESSFUL) {
                  num_ticks--;
                  if (num_ticks == EXPIRED_TIMER)
                        return -ETIME;
            }
            break;

      case HC_SMITYPE_TYPE2:
      case HC_SMITYPE_TYPE3:
            spin_lock_irqsave(&rtc_lock, flags);
            /* write SMI data buffer physical address */
            data = (u8 *)&smi_data_buf_phys_addr;
            for (index = PE1400_CMOS_CMD_STRUCT_PTR;
                 index < (PE1400_CMOS_CMD_STRUCT_PTR + 4);
                 index++, data++) {
                  outb(index, (CMOS_BASE_PORT + CMOS_PAGE1_INDEX_PORT));
                  outb(*data, (CMOS_BASE_PORT + CMOS_PAGE1_DATA_PORT));
            }

            /* generate SMM call */
            if (host_control_smi_type == HC_SMITYPE_TYPE3)
                  outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
            else
                  outb(ESM_APM_CMD, PE1400_APM_CONTROL_PORT);

            /* restore RTC index pointer since it was written to above */
            CMOS_READ(RTC_REG_C);
            spin_unlock_irqrestore(&rtc_lock, flags);

            /* read control port back to serialize write */
            cmd_status = inb(PE1400_APM_CONTROL_PORT);

            /* wait a few to see if it executed */
            num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
            while (apm_cmd->status == ESM_STATUS_CMD_UNSUCCESSFUL) {
                  num_ticks--;
                  if (num_ticks == EXPIRED_TIMER)
                        return -ETIME;
            }
            break;

      default:
            dev_dbg(&dcdbas_pdev->dev, "%s: invalid SMI type %u\n",
                  __FUNCTION__, host_control_smi_type);
            return -ENOSYS;
      }

      return 0;
}

/**
 * dcdbas_host_control: initiate host control
 *
 * This function is called by the driver after the system has
 * finished shutting down if the user application specified a
 * host control action to perform on shutdown.  It is safe to
 * use smi_data_buf at this point because the system has finished
 * shutting down and no userspace apps are running.
 */
static void dcdbas_host_control(void)
{
      struct apm_cmd *apm_cmd;
      u8 action;

      if (host_control_action == HC_ACTION_NONE)
            return;

      action = host_control_action;
      host_control_action = HC_ACTION_NONE;

      if (!smi_data_buf) {
            dev_dbg(&dcdbas_pdev->dev, "%s: no SMI buffer\n", __FUNCTION__);
            return;
      }

      if (smi_data_buf_size < sizeof(struct apm_cmd)) {
            dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",
                  __FUNCTION__);
            return;
      }

      apm_cmd = (struct apm_cmd *)smi_data_buf;

      /* power off takes precedence */
      if (action & HC_ACTION_HOST_CONTROL_POWEROFF) {
            apm_cmd->command = ESM_APM_POWER_CYCLE;
            apm_cmd->reserved = 0;
            *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 0;
            host_control_smi();
      } else if (action & HC_ACTION_HOST_CONTROL_POWERCYCLE) {
            apm_cmd->command = ESM_APM_POWER_CYCLE;
            apm_cmd->reserved = 0;
            *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 20;
            host_control_smi();
      }
}

/**
 * dcdbas_reboot_notify: handle reboot notification for host control
 */
static int dcdbas_reboot_notify(struct notifier_block *nb, unsigned long code,
                        void *unused)
{
      switch (code) {
      case SYS_DOWN:
      case SYS_HALT:
      case SYS_POWER_OFF:
            if (host_control_on_shutdown) {
                  /* firmware is going to perform host control action */
                  printk(KERN_WARNING "Please wait for shutdown "
                         "action to complete...\n");
                  dcdbas_host_control();
            }
            break;
      }

      return NOTIFY_DONE;
}

static struct notifier_block dcdbas_reboot_nb = {
      .notifier_call = dcdbas_reboot_notify,
      .next = NULL,
      .priority = INT_MIN
};

static DCDBAS_BIN_ATTR_RW(smi_data);

static struct bin_attribute *dcdbas_bin_attrs[] = {
      &bin_attr_smi_data,
      NULL
};

static DCDBAS_DEV_ATTR_RW(smi_data_buf_size);
static DCDBAS_DEV_ATTR_RO(smi_data_buf_phys_addr);
static DCDBAS_DEV_ATTR_WO(smi_request);
static DCDBAS_DEV_ATTR_RW(host_control_action);
static DCDBAS_DEV_ATTR_RW(host_control_smi_type);
static DCDBAS_DEV_ATTR_RW(host_control_on_shutdown);

static struct attribute *dcdbas_dev_attrs[] = {
      &dev_attr_smi_data_buf_size.attr,
      &dev_attr_smi_data_buf_phys_addr.attr,
      &dev_attr_smi_request.attr,
      &dev_attr_host_control_action.attr,
      &dev_attr_host_control_smi_type.attr,
      &dev_attr_host_control_on_shutdown.attr,
      NULL
};

static struct attribute_group dcdbas_attr_group = {
      .attrs = dcdbas_dev_attrs,
};

static int __devinit dcdbas_probe(struct platform_device *dev)
{
      int i, error;

      host_control_action = HC_ACTION_NONE;
      host_control_smi_type = HC_SMITYPE_NONE;

      /*
       * BIOS SMI calls require buffer addresses be in 32-bit address space.
       * This is done by setting the DMA mask below.
       */
      dcdbas_pdev->dev.coherent_dma_mask = DMA_32BIT_MASK;
      dcdbas_pdev->dev.dma_mask = &dcdbas_pdev->dev.coherent_dma_mask;

      error = sysfs_create_group(&dev->dev.kobj, &dcdbas_attr_group);
      if (error)
            return error;

      for (i = 0; dcdbas_bin_attrs[i]; i++) {
            error = sysfs_create_bin_file(&dev->dev.kobj,
                                    dcdbas_bin_attrs[i]);
            if (error) {
                  while (--i >= 0)
                        sysfs_remove_bin_file(&dev->dev.kobj,
                                          dcdbas_bin_attrs[i]);
                  sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);
                  return error;
            }
      }

      register_reboot_notifier(&dcdbas_reboot_nb);

      dev_info(&dev->dev, "%s (version %s)\n",
             DRIVER_DESCRIPTION, DRIVER_VERSION);

      return 0;
}

static int __devexit dcdbas_remove(struct platform_device *dev)
{
      int i;

      unregister_reboot_notifier(&dcdbas_reboot_nb);
      for (i = 0; dcdbas_bin_attrs[i]; i++)
            sysfs_remove_bin_file(&dev->dev.kobj, dcdbas_bin_attrs[i]);
      sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);

      return 0;
}

static struct platform_driver dcdbas_driver = {
      .driver           = {
            .name = DRIVER_NAME,
            .owner      = THIS_MODULE,
      },
      .probe            = dcdbas_probe,
      .remove           = __devexit_p(dcdbas_remove),
};

/**
 * dcdbas_init: initialize driver
 */
static int __init dcdbas_init(void)
{
      int error;

      error = platform_driver_register(&dcdbas_driver);
      if (error)
            return error;

      dcdbas_pdev = platform_device_alloc(DRIVER_NAME, -1);
      if (!dcdbas_pdev) {
            error = -ENOMEM;
            goto err_unregister_driver;
      }

      error = platform_device_add(dcdbas_pdev);
      if (error)
            goto err_free_device;

      return 0;

 err_free_device:
      platform_device_put(dcdbas_pdev);
 err_unregister_driver:
      platform_driver_unregister(&dcdbas_driver);
      return error;
}

/**
 * dcdbas_exit: perform driver cleanup
 */
static void __exit dcdbas_exit(void)
{
      /*
       * make sure functions that use dcdbas_pdev are called
       * before platform_device_unregister
       */
      unregister_reboot_notifier(&dcdbas_reboot_nb);
      smi_data_buf_free();
      platform_device_unregister(dcdbas_pdev);
      platform_driver_unregister(&dcdbas_driver);

      /*
       * We have to free the buffer here instead of dcdbas_remove
       * because only in module exit function we can be sure that
       * all sysfs attributes belonging to this module have been
       * released.
       */
      smi_data_buf_free();
}

module_init(dcdbas_init);
module_exit(dcdbas_exit);

MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
MODULE_VERSION(DRIVER_VERSION);
MODULE_AUTHOR("Dell Inc.");
MODULE_LICENSE("GPL");


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