1/*
  2 * Toshiba HDD Active Protection Sensor (HAPS) driver
  3 *
  4 * Copyright (C) 2014 Azael Avalos <coproscefalo@gmail.com>
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License as published by
  8 * the Free Software Foundation; either version 2 of the License, or
  9 * (at your option) any later version.
 10 *
 11 * This program is distributed in the hope that it will be useful,
 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14 * GNU General Public License for more details.
 15 *
 16 */
 17
 18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 19
 20#include <linux/kernel.h>
 21#include <linux/module.h>
 22#include <linux/init.h>
 23#include <linux/types.h>
 24#include <linux/acpi.h>
 25
 26MODULE_AUTHOR("Azael Avalos <coproscefalo@gmail.com>");
 27MODULE_DESCRIPTION("Toshiba HDD Active Protection Sensor");
 28MODULE_LICENSE("GPL");
 29
 30struct toshiba_haps_dev {
 31	struct acpi_device *acpi_dev;
 32
 33	int protection_level;
 34};
 35
 36static struct toshiba_haps_dev *toshiba_haps;
 37
 38/* HAPS functions */
 39static int toshiba_haps_reset_protection(acpi_handle handle)
 40{
 41	acpi_status status;
 42
 43	status = acpi_evaluate_object(handle, "RSSS", NULL, NULL);
 44	if (ACPI_FAILURE(status)) {
 45		pr_err("Unable to reset the HDD protection\n");
 46		return -EIO;
 47	}
 48
 49	return 0;
 50}
 51
 52static int toshiba_haps_protection_level(acpi_handle handle, int level)
 53{
 54	acpi_status status;
 55
 56	status = acpi_execute_simple_method(handle, "PTLV", level);
 57	if (ACPI_FAILURE(status)) {
 58		pr_err("Error while setting the protection level\n");
 59		return -EIO;
 60	}
 61
 62	pr_info("HDD protection level set to: %d\n", level);
 63
 64	return 0;
 65}
 66
 67/* sysfs files */
 68static ssize_t protection_level_show(struct device *dev,
 69				     struct device_attribute *attr, char *buf)
 70{
 71	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);
 72
 73	return sprintf(buf, "%i\n", haps->protection_level);
 74}
 75
 76static ssize_t protection_level_store(struct device *dev,
 77				      struct device_attribute *attr,
 78				      const char *buf, size_t count)
 79{
 80	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);
 81	int level;
 82	int ret;
 83
 84	ret = kstrtoint(buf, 0, &level);
 85	if (ret)
 86		return ret;
 87	/*
 88	 * Check for supported levels, which can be:
 89	 * 0 - Disabled | 1 - Low | 2 - Medium | 3 - High
 90	 */
 91	if (level < 0 || level > 3)
 92		return -EINVAL;
 93
 94	/* Set the sensor level */
 95	ret = toshiba_haps_protection_level(haps->acpi_dev->handle, level);
 96	if (ret != 0)
 97		return ret;
 98
 99	haps->protection_level = level;
100
101	return count;
102}
103static DEVICE_ATTR_RW(protection_level);
104
105static ssize_t reset_protection_store(struct device *dev,
106				      struct device_attribute *attr,
107				      const char *buf, size_t count)
108{
109	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);
110	int reset;
111	int ret;
112
113	ret = kstrtoint(buf, 0, &reset);
114	if (ret)
115		return ret;
116	/* The only accepted value is 1 */
117	if (reset != 1)
118		return -EINVAL;
119
120	/* Reset the protection interface */
121	ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);
122	if (ret != 0)
123		return ret;
124
125	return count;
126}
127static DEVICE_ATTR_WO(reset_protection);
128
129static struct attribute *haps_attributes[] = {
130	&dev_attr_protection_level.attr,
131	&dev_attr_reset_protection.attr,
132	NULL,
133};
134
135static struct attribute_group haps_attr_group = {
136	.attrs = haps_attributes,
137};
138
139/*
140 * ACPI stuff
141 */
142static void toshiba_haps_notify(struct acpi_device *device, u32 event)
143{
144	pr_info("Received event: 0x%x", event);
145
146	acpi_bus_generate_netlink_event(device->pnp.device_class,
147					dev_name(&device->dev),
148					event, 0);
149}
150
151static int toshiba_haps_remove(struct acpi_device *device)
152{
153	sysfs_remove_group(&device->dev.kobj, &haps_attr_group);
154
155	if (toshiba_haps)
156		toshiba_haps = NULL;
157
158	return 0;
159}
160
161/* Helper function */
162static int toshiba_haps_available(acpi_handle handle)
163{
164	acpi_status status;
165	u64 hdd_present;
166
167	/*
168	 * A non existent device as well as having (only)
169	 * Solid State Drives can cause the call to fail.
170	 */
171	status = acpi_evaluate_integer(handle, "_STA", NULL,
172				       &hdd_present);
173	if (ACPI_FAILURE(status) || !hdd_present) {
174		pr_info("HDD protection not available or using SSD\n");
175		return 0;
176	}
177
178	return 1;
179}
180
181static int toshiba_haps_add(struct acpi_device *acpi_dev)
182{
183	struct toshiba_haps_dev *haps;
184	int ret;
185
186	if (toshiba_haps)
187		return -EBUSY;
188
189	if (!toshiba_haps_available(acpi_dev->handle))
190		return -ENODEV;
191
192	pr_info("Toshiba HDD Active Protection Sensor device\n");
193
194	haps = kzalloc(sizeof(struct toshiba_haps_dev), GFP_KERNEL);
195	if (!haps)
196		return -ENOMEM;
197
198	haps->acpi_dev = acpi_dev;
199	haps->protection_level = 2;
200	acpi_dev->driver_data = haps;
201	dev_set_drvdata(&acpi_dev->dev, haps);
202
203	/* Set the protection level, currently at level 2 (Medium) */
204	ret = toshiba_haps_protection_level(acpi_dev->handle, 2);
205	if (ret != 0)
206		return ret;
207
208	ret = sysfs_create_group(&acpi_dev->dev.kobj, &haps_attr_group);
209	if (ret)
210		return ret;
211
212	toshiba_haps = haps;
213
214	return 0;
215}
216
217#ifdef CONFIG_PM_SLEEP
218static int toshiba_haps_suspend(struct device *device)
219{
220	struct toshiba_haps_dev *haps;
221	int ret;
222
223	haps = acpi_driver_data(to_acpi_device(device));
224
225	/* Deactivate the protection on suspend */
226	ret = toshiba_haps_protection_level(haps->acpi_dev->handle, 0);
227
228	return ret;
229}
230
231static int toshiba_haps_resume(struct device *device)
232{
233	struct toshiba_haps_dev *haps;
234	int ret;
235
236	haps = acpi_driver_data(to_acpi_device(device));
237
238	/* Set the stored protection level */
239	ret = toshiba_haps_protection_level(haps->acpi_dev->handle,
240					    haps->protection_level);
241
242	/* Reset the protection on resume */
243	ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);
244	if (ret != 0)
245		return ret;
246
247	return ret;
248}
249#endif
250
251static SIMPLE_DEV_PM_OPS(toshiba_haps_pm,
252			 toshiba_haps_suspend, toshiba_haps_resume);
253
254static const struct acpi_device_id haps_device_ids[] = {
255	{"TOS620A", 0},
256	{"", 0},
257};
258MODULE_DEVICE_TABLE(acpi, haps_device_ids);
259
260static struct acpi_driver toshiba_haps_driver = {
261	.name = "Toshiba HAPS",
262	.owner = THIS_MODULE,
263	.ids = haps_device_ids,
264	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
265	.ops = {
266		.add =		toshiba_haps_add,
267		.remove =	toshiba_haps_remove,
268		.notify =	toshiba_haps_notify,
269	},
270	.drv.pm = &toshiba_haps_pm,
271};
272
273module_acpi_driver(toshiba_haps_driver);