dcdbas.c

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		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");