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 
26 MODULE_AUTHOR("Azael Avalos <coproscefalo@gmail.com>");
27 MODULE_DESCRIPTION("Toshiba HDD Active Protection Sensor");
28 MODULE_LICENSE("GPL");
29 
30 struct toshiba_haps_dev {
31 	struct acpi_device *acpi_dev;
32 
33 	int protection_level;
34 };
35 
36 static struct toshiba_haps_dev *toshiba_haps;
37 
38 /* HAPS functions */
39 static 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 
52 static 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_debug("HDD protection level set to: %d\n", level);
63 
64 	return 0;
65 }
66 
67 /* sysfs files */
68 static 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 
76 static 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 }
103 static DEVICE_ATTR_RW(protection_level);
104 
105 static 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 }
127 static DEVICE_ATTR_WO(reset_protection);
128 
129 static struct attribute *haps_attributes[] = {
130 	&dev_attr_protection_level.attr,
131 	&dev_attr_reset_protection.attr,
132 	NULL,
133 };
134 
135 static const struct attribute_group haps_attr_group = {
136 	.attrs = haps_attributes,
137 };
138 
139 /*
140  * ACPI stuff
141  */
142 static void toshiba_haps_notify(struct acpi_device *device, u32 event)
143 {
144 	pr_debug("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 
151 static 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 */
162 static 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, &hdd_present);
172 	if (ACPI_FAILURE(status)) {
173 		pr_err("ACPI call to query HDD protection failed\n");
174 		return 0;
175 	}
176 
177 	if (!hdd_present) {
178 		pr_info("HDD protection not available or using SSD\n");
179 		return 0;
180 	}
181 
182 	return 1;
183 }
184 
185 static int toshiba_haps_add(struct acpi_device *acpi_dev)
186 {
187 	struct toshiba_haps_dev *haps;
188 	int ret;
189 
190 	if (toshiba_haps)
191 		return -EBUSY;
192 
193 	if (!toshiba_haps_available(acpi_dev->handle))
194 		return -ENODEV;
195 
196 	pr_info("Toshiba HDD Active Protection Sensor device\n");
197 
198 	haps = kzalloc(sizeof(struct toshiba_haps_dev), GFP_KERNEL);
199 	if (!haps)
200 		return -ENOMEM;
201 
202 	haps->acpi_dev = acpi_dev;
203 	haps->protection_level = 2;
204 	acpi_dev->driver_data = haps;
205 	dev_set_drvdata(&acpi_dev->dev, haps);
206 
207 	/* Set the protection level, currently at level 2 (Medium) */
208 	ret = toshiba_haps_protection_level(acpi_dev->handle, 2);
209 	if (ret != 0)
210 		return ret;
211 
212 	ret = sysfs_create_group(&acpi_dev->dev.kobj, &haps_attr_group);
213 	if (ret)
214 		return ret;
215 
216 	toshiba_haps = haps;
217 
218 	return 0;
219 }
220 
221 #ifdef CONFIG_PM_SLEEP
222 static int toshiba_haps_suspend(struct device *device)
223 {
224 	struct toshiba_haps_dev *haps;
225 	int ret;
226 
227 	haps = acpi_driver_data(to_acpi_device(device));
228 
229 	/* Deactivate the protection on suspend */
230 	ret = toshiba_haps_protection_level(haps->acpi_dev->handle, 0);
231 
232 	return ret;
233 }
234 
235 static int toshiba_haps_resume(struct device *device)
236 {
237 	struct toshiba_haps_dev *haps;
238 	int ret;
239 
240 	haps = acpi_driver_data(to_acpi_device(device));
241 
242 	/* Set the stored protection level */
243 	ret = toshiba_haps_protection_level(haps->acpi_dev->handle,
244 					    haps->protection_level);
245 
246 	/* Reset the protection on resume */
247 	ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);
248 	if (ret != 0)
249 		return ret;
250 
251 	return ret;
252 }
253 #endif
254 
255 static SIMPLE_DEV_PM_OPS(toshiba_haps_pm,
256 			 toshiba_haps_suspend, toshiba_haps_resume);
257 
258 static const struct acpi_device_id haps_device_ids[] = {
259 	{"TOS620A", 0},
260 	{"", 0},
261 };
262 MODULE_DEVICE_TABLE(acpi, haps_device_ids);
263 
264 static struct acpi_driver toshiba_haps_driver = {
265 	.name = "Toshiba HAPS",
266 	.owner = THIS_MODULE,
267 	.ids = haps_device_ids,
268 	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
269 	.ops = {
270 		.add =		toshiba_haps_add,
271 		.remove =	toshiba_haps_remove,
272 		.notify =	toshiba_haps_notify,
273 	},
274 	.drv.pm = &toshiba_haps_pm,
275 };
276 
277 module_acpi_driver(toshiba_haps_driver);
278