platform/x86: Toshiba HDD Active Protection Sensor

/*

 * Toshiba HDD Active Protection Sensor (HAPS) driver

 *

 * Copyright (C) 2014 Azael Avalos <coproscefalo@gmail.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * 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.

 *

 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/types.h>

#include <linux/acpi.h>

MODULE_AUTHOR("Azael Avalos <coproscefalo@gmail.com>");

MODULE_DESCRIPTION("Toshiba HDD Active Protection Sensor");

MODULE_LICENSE("GPL");

struct toshiba_haps_dev {

	struct acpi_device *acpi_dev;

	int protection_level;

};

static struct toshiba_haps_dev *toshiba_haps;

/* HAPS functions */

static int toshiba_haps_reset_protection(acpi_handle handle)

{

	acpi_status status;

	status = acpi_evaluate_object(handle, "RSSS", NULL, NULL);

	if (ACPI_FAILURE(status)) {

		pr_err("Unable to reset the HDD protection\n");

		return -EIO;

	}

	return 0;

}

static int toshiba_haps_protection_level(acpi_handle handle, int level)

{

	acpi_status status;

	status = acpi_execute_simple_method(handle, "PTLV", level);

	if (ACPI_FAILURE(status)) {

		pr_err("Error while setting the protection level\n");

		return -EIO;

	}

	pr_info("HDD protection level set to: %d\n", level);

	return 0;

}

/* sysfs files */

static ssize_t protection_level_show(struct device *dev,

				     struct device_attribute *attr, char *buf)

{

	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);

	return sprintf(buf, "%i\n", haps->protection_level);

}

static ssize_t protection_level_store(struct device *dev,

				      struct device_attribute *attr,

				      const char *buf, size_t count)

{

	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);

	int level, ret;

	if (sscanf(buf, "%d", &level) != 1 || level < 0 || level > 3)

		return -EINVAL;

	/* Set the sensor level.

	 * Acceptable levels are:

	 * 0 - Disabled | 1 - Low | 2 - Medium | 3 - High

	 */

	ret = toshiba_haps_protection_level(haps->acpi_dev->handle, level);

	if (ret != 0)

		return ret;

	haps->protection_level = level;

	return count;

}

static ssize_t reset_protection_store(struct device *dev,

				      struct device_attribute *attr,

				      const char *buf, size_t count)

{

	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);

	int reset, ret;

	if (sscanf(buf, "%d", &reset) != 1 || reset != 1)

		return -EINVAL;

	/* Reset the protection interface */

	ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);

	if (ret != 0)

		return ret;

	return count;

}

static DEVICE_ATTR(protection_level, S_IRUGO | S_IWUSR,

		   protection_level_show, protection_level_store);

static DEVICE_ATTR(reset_protection, S_IWUSR, NULL, reset_protection_store);

static struct attribute *haps_attributes[] = {

	&dev_attr_protection_level.attr,

	&dev_attr_reset_protection.attr,

	NULL,

};

static struct attribute_group haps_attr_group = {

	.attrs = haps_attributes,

};

/*

 * ACPI stuff

 */

static void toshiba_haps_notify(struct acpi_device *device, u32 event)

{

	pr_info("Received event: 0x%x", event);

	acpi_bus_generate_netlink_event(device->pnp.device_class,

					dev_name(&device->dev),

					event, 0);

}

static int toshiba_haps_remove(struct acpi_device *device)

{

	sysfs_remove_group(&device->dev.kobj, &haps_attr_group);

	if (toshiba_haps)

		toshiba_haps = NULL;

	return 0;

}

/* Helper function */

static int toshiba_haps_available(acpi_handle handle)

{

	acpi_status status;

	u64 hdd_present;

	/*

	 * A non existent device as well as having (only)

	 * Solid State Drives can cause the call to fail.

	 */

	status = acpi_evaluate_integer(handle, "_STA", NULL,

				       &hdd_present);

	if (ACPI_FAILURE(status) || !hdd_present) {

		pr_info("HDD protection not available or using SSD\n");

		return 0;

	}

	return 1;

}

static int toshiba_haps_add(struct acpi_device *acpi_dev)

{

	struct toshiba_haps_dev *haps;

	int ret;

	if (toshiba_haps)

		return -EBUSY;

	if (!toshiba_haps_available(acpi_dev->handle))

		return -ENODEV;

	pr_info("Toshiba HDD Active Protection Sensor device\n");

	haps = kzalloc(sizeof(struct toshiba_haps_dev), GFP_KERNEL);

	if (!haps)

		return -ENOMEM;

	haps->acpi_dev = acpi_dev;

	haps->protection_level = 2;

	acpi_dev->driver_data = haps;

	dev_set_drvdata(&acpi_dev->dev, haps);

	/* Set the protection level, currently at level 2 (Medium) */

	ret = toshiba_haps_protection_level(acpi_dev->handle, 2);

	if (ret != 0)

		return ret;

	ret = sysfs_create_group(&acpi_dev->dev.kobj, &haps_attr_group);

	if (ret)

		return ret;

	toshiba_haps = haps;

	return 0;

}

#ifdef CONFIG_PM_SLEEP

static int toshiba_haps_suspend(struct device *device)

{

	struct toshiba_haps_dev *haps;

	int ret;

	haps = acpi_driver_data(to_acpi_device(device));

	/* Deactivate the protection on suspend */

	ret = toshiba_haps_protection_level(haps->acpi_dev->handle, 0);

	return ret;

}

static int toshiba_haps_resume(struct device *device)

{

	struct toshiba_haps_dev *haps;

	int ret;

	haps = acpi_driver_data(to_acpi_device(device));

	/* Set the stored protection level */

	ret = toshiba_haps_protection_level(haps->acpi_dev->handle,

					    haps->protection_level);

	/* Reset the protection on resume */

	ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);

	if (ret != 0)

		return ret;

	return ret;

}

#endif

static SIMPLE_DEV_PM_OPS(toshiba_haps_pm,

			 toshiba_haps_suspend, toshiba_haps_resume);

static const struct acpi_device_id haps_device_ids[] = {

	{"TOS620A", 0},

	{"", 0},

};

MODULE_DEVICE_TABLE(acpi, haps_device_ids);

static struct acpi_driver toshiba_haps_driver = {

	.name = "Toshiba HAPS",

	.owner = THIS_MODULE,

	.ids = haps_device_ids,

	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,

	.ops = {

		.add =		toshiba_haps_add,

		.remove =	toshiba_haps_remove,

		.notify =	toshiba_haps_notify,

	},

	.drv.pm = &toshiba_haps_pm,

};

module_acpi_driver(toshiba_haps_driver);