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, ret;
82
83	if (sscanf(buf, "%d", &level) != 1 || level < 0 || level > 3)
84		return -EINVAL;
85
86	/* Set the sensor level.
87	 * Acceptable levels are:
88	 * 0 - Disabled | 1 - Low | 2 - Medium | 3 - High
89	 */
90	ret = toshiba_haps_protection_level(haps->acpi_dev->handle, level);
91	if (ret != 0)
92		return ret;
93
94	haps->protection_level = level;
95
96	return count;
97}
98
99static ssize_t reset_protection_store(struct device *dev,
100				      struct device_attribute *attr,
101				      const char *buf, size_t count)
102{
103	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);
104	int reset, ret;
105
106	if (sscanf(buf, "%d", &reset) != 1 || reset != 1)
107		return -EINVAL;
108
109	/* Reset the protection interface */
110	ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);
111	if (ret != 0)
112		return ret;
113
114	return count;
115}
116
117static DEVICE_ATTR(protection_level, S_IRUGO | S_IWUSR,
118		   protection_level_show, protection_level_store);
119static DEVICE_ATTR(reset_protection, S_IWUSR, NULL, reset_protection_store);
120
121static struct attribute *haps_attributes[] = {
122	&dev_attr_protection_level.attr,
123	&dev_attr_reset_protection.attr,
124	NULL,
125};
126
127static struct attribute_group haps_attr_group = {
128	.attrs = haps_attributes,
129};
130
131/*
132 * ACPI stuff
133 */
134static void toshiba_haps_notify(struct acpi_device *device, u32 event)
135{
136	pr_info("Received event: 0x%x", event);
137
138	acpi_bus_generate_netlink_event(device->pnp.device_class,
139					dev_name(&device->dev),
140					event, 0);
141}
142
143static int toshiba_haps_remove(struct acpi_device *device)
144{
145	sysfs_remove_group(&device->dev.kobj, &haps_attr_group);
146
147	if (toshiba_haps)
148		toshiba_haps = NULL;
149
150	return 0;
151}
152
153/* Helper function */
154static int toshiba_haps_available(acpi_handle handle)
155{
156	acpi_status status;
157	u64 hdd_present;
158
159	/*
160	 * A non existent device as well as having (only)
161	 * Solid State Drives can cause the call to fail.
162	 */
163	status = acpi_evaluate_integer(handle, "_STA", NULL,
164				       &hdd_present);
165	if (ACPI_FAILURE(status) || !hdd_present) {
166		pr_info("HDD protection not available or using SSD\n");
167		return 0;
168	}
169
170	return 1;
171}
172
173static int toshiba_haps_add(struct acpi_device *acpi_dev)
174{
175	struct toshiba_haps_dev *haps;
176	int ret;
177
178	if (toshiba_haps)
179		return -EBUSY;
180
181	if (!toshiba_haps_available(acpi_dev->handle))
182		return -ENODEV;
183
184	pr_info("Toshiba HDD Active Protection Sensor device\n");
185
186	haps = kzalloc(sizeof(struct toshiba_haps_dev), GFP_KERNEL);
187	if (!haps)
188		return -ENOMEM;
189
190	haps->acpi_dev = acpi_dev;
191	haps->protection_level = 2;
192	acpi_dev->driver_data = haps;
193	dev_set_drvdata(&acpi_dev->dev, haps);
194
195	/* Set the protection level, currently at level 2 (Medium) */
196	ret = toshiba_haps_protection_level(acpi_dev->handle, 2);
197	if (ret != 0)
198		return ret;
199
200	ret = sysfs_create_group(&acpi_dev->dev.kobj, &haps_attr_group);
201	if (ret)
202		return ret;
203
204	toshiba_haps = haps;
205
206	return 0;
207}
208
209#ifdef CONFIG_PM_SLEEP
210static int toshiba_haps_suspend(struct device *device)
211{
212	struct toshiba_haps_dev *haps;
213	int ret;
214
215	haps = acpi_driver_data(to_acpi_device(device));
216
217	/* Deactivate the protection on suspend */
218	ret = toshiba_haps_protection_level(haps->acpi_dev->handle, 0);
219
220	return ret;
221}
222
223static int toshiba_haps_resume(struct device *device)
224{
225	struct toshiba_haps_dev *haps;
226	int ret;
227
228	haps = acpi_driver_data(to_acpi_device(device));
229
230	/* Set the stored protection level */
231	ret = toshiba_haps_protection_level(haps->acpi_dev->handle,
232					    haps->protection_level);
233
234	/* Reset the protection on resume */
235	ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);
236	if (ret != 0)
237		return ret;
238
239	return ret;
240}
241#endif
242
243static SIMPLE_DEV_PM_OPS(toshiba_haps_pm,
244			 toshiba_haps_suspend, toshiba_haps_resume);
245
246static const struct acpi_device_id haps_device_ids[] = {
247	{"TOS620A", 0},
248	{"", 0},
249};
250MODULE_DEVICE_TABLE(acpi, haps_device_ids);
251
252static struct acpi_driver toshiba_haps_driver = {
253	.name = "Toshiba HAPS",
254	.owner = THIS_MODULE,
255	.ids = haps_device_ids,
256	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
257	.ops = {
258		.add =		toshiba_haps_add,
259		.remove =	toshiba_haps_remove,
260		.notify =	toshiba_haps_notify,
261	},
262	.drv.pm = &toshiba_haps_pm,
263};
264
265module_acpi_driver(toshiba_haps_driver);
266