/*
   *  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/gfp.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 "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
  ",
  		__func__, 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
  ",
  			__func__, 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
  ",
  		__func__, 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
  ", 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
  ", 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 file *filp, struct kobject *kobj,
  			     struct bin_attribute *bin_attr,
  			     char *buf, loff_t pos, size_t count)
  {
  	ssize_t ret;
  
  	mutex_lock(&smi_data_lock);
  	ret = memory_read_from_buffer(buf, count, &pos, smi_data_buf,
  					smi_data_buf_size);
  	mutex_unlock(&smi_data_lock);
  	return ret;
  }
  
  static ssize_t smi_data_write(struct file *filp, 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
  ", 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
  ", 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
  ", 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;
  }
  
  /**
   * dcdbas_smi_request: generate SMI request
   *
   * Called with smi_data_lock.
   */
  int dcdbas_smi_request(struct smi_cmd *smi_cmd)
  {
  	cpumask_var_t old_mask;
  	int ret = 0;
  
  	if (smi_cmd->magic != SMI_CMD_MAGIC) {
  		dev_info(&dcdbas_pdev->dev, "%s: invalid magic value
  ",
  			 __func__);
  		return -EBADR;
  	}
  
  	/* SMI requires CPU 0 */
  	if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
  		return -ENOMEM;
  
  	cpumask_copy(old_mask, &current->cpus_allowed);
  	set_cpus_allowed_ptr(current, cpumask_of(0));
  	if (smp_processor_id() != 0) {
  		dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0
  ",
  			__func__);
  		ret = -EBUSY;
  		goto out;
  	}
  
  	/* generate SMI */
  	/* inb to force posted write through and make SMI happen now */
  	asm volatile (
  		"outb %b0,%w1
  "
  		"inb %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_ptr(current, old_mask);
  	free_cpumask_var(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 = dcdbas_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 = dcdbas_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;
  }
  EXPORT_SYMBOL(dcdbas_smi_request);
  
  /**
   * 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
  ",
  			__func__, 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
  ", __func__);
  		return;
  	}
  
  	if (smi_data_buf_size < sizeof(struct apm_cmd)) {
  		dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small
  ",
  			__func__);
  		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...
  ");
  			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,
  	.bin_attrs = dcdbas_bin_attrs,
  };
  
  static int dcdbas_probe(struct platform_device *dev)
  {
  	int error;
  
  	host_control_action = HC_ACTION_NONE;
  	host_control_smi_type = HC_SMITYPE_NONE;
  
  	dcdbas_pdev = dev;
  
  	/*
  	 * BIOS SMI calls require buffer addresses be in 32-bit address space.
  	 * This is done by setting the DMA mask below.
  	 */
  	error = dma_set_coherent_mask(&dcdbas_pdev->dev, DMA_BIT_MASK(32));
  	if (error)
  		return error;
  
  	error = sysfs_create_group(&dev->dev.kobj, &dcdbas_attr_group);
  	if (error)
  		return error;
  
  	register_reboot_notifier(&dcdbas_reboot_nb);
  
  	dev_info(&dev->dev, "%s (version %s)
  ",
  		 DRIVER_DESCRIPTION, DRIVER_VERSION);
  
  	return 0;
  }
  
  static int dcdbas_remove(struct platform_device *dev)
  {
  	unregister_reboot_notifier(&dcdbas_reboot_nb);
  	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		= dcdbas_remove,
  };
  
  static const struct platform_device_info dcdbas_dev_info __initdata = {
  	.name		= DRIVER_NAME,
  	.id		= -1,
  	.dma_mask	= DMA_BIT_MASK(32),
  };
  
  static struct platform_device *dcdbas_pdev_reg;
  
  /**
   * dcdbas_init: initialize driver
   */
  static int __init dcdbas_init(void)
  {
  	int error;
  
  	error = platform_driver_register(&dcdbas_driver);
  	if (error)
  		return error;
  
  	dcdbas_pdev_reg = platform_device_register_full(&dcdbas_dev_info);
  	if (IS_ERR(dcdbas_pdev_reg)) {
  		error = PTR_ERR(dcdbas_pdev_reg);
  		goto err_unregister_driver;
  	}
  
  	return 0;
  
   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);
  
  	/*
  	 * 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.
  	 */
  	if (dcdbas_pdev)
  		smi_data_buf_free();
  	platform_device_unregister(dcdbas_pdev_reg);
  	platform_driver_unregister(&dcdbas_driver);
  }
  
  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");
  /* Any System or BIOS claiming to be by Dell */
  MODULE_ALIAS("dmi:*:[bs]vnD[Ee][Ll][Ll]*:*");