1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Toshiba HDD Active Protection Sensor (HAPS) driver
4 *
5 * Copyright (C) 2014 Azael Avalos <coproscefalo@gmail.com>
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/types.h>
14#include <linux/acpi.h>
15
16MODULE_AUTHOR("Azael Avalos <coproscefalo@gmail.com>");
17MODULE_DESCRIPTION("Toshiba HDD Active Protection Sensor");
18MODULE_LICENSE("GPL");
19
20struct toshiba_haps_dev {
21	struct acpi_device *acpi_dev;
22
23	int protection_level;
24};
25
26static struct toshiba_haps_dev *toshiba_haps;
27
28/* HAPS functions */
29static int toshiba_haps_reset_protection(acpi_handle handle)
30{
31	acpi_status status;
32
33	status = acpi_evaluate_object(handle, "RSSS", NULL, NULL);
34	if (ACPI_FAILURE(status)) {
35		pr_err("Unable to reset the HDD protection\n");
36		return -EIO;
37	}
38
39	return 0;
40}
41
42static int toshiba_haps_protection_level(acpi_handle handle, int level)
43{
44	acpi_status status;
45
46	status = acpi_execute_simple_method(handle, "PTLV", level);
47	if (ACPI_FAILURE(status)) {
48		pr_err("Error while setting the protection level\n");
49		return -EIO;
50	}
51
52	pr_debug("HDD protection level set to: %d\n", level);
53
54	return 0;
55}
56
57/* sysfs files */
58static ssize_t protection_level_show(struct device *dev,
59				     struct device_attribute *attr, char *buf)
60{
61	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);
62
63	return sprintf(buf, "%i\n", haps->protection_level);
64}
65
66static ssize_t protection_level_store(struct device *dev,
67				      struct device_attribute *attr,
68				      const char *buf, size_t count)
69{
70	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);
71	int level;
72	int ret;
73
74	ret = kstrtoint(buf, 0, &level);
75	if (ret)
76		return ret;
77	/*
78	 * Check for supported levels, which can be:
79	 * 0 - Disabled | 1 - Low | 2 - Medium | 3 - High
80	 */
81	if (level < 0 || level > 3)
82		return -EINVAL;
83
84	/* Set the sensor level */
85	ret = toshiba_haps_protection_level(haps->acpi_dev->handle, level);
86	if (ret != 0)
87		return ret;
88
89	haps->protection_level = level;
90
91	return count;
92}
93static DEVICE_ATTR_RW(protection_level);
94
95static ssize_t reset_protection_store(struct device *dev,
96				      struct device_attribute *attr,
97				      const char *buf, size_t count)
98{
99	struct toshiba_haps_dev *haps = dev_get_drvdata(dev);
100	int reset;
101	int ret;
102
103	ret = kstrtoint(buf, 0, &reset);
104	if (ret)
105		return ret;
106	/* The only accepted value is 1 */
107	if (reset != 1)
108		return -EINVAL;
109
110	/* Reset the protection interface */
111	ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);
112	if (ret != 0)
113		return ret;
114
115	return count;
116}
117static DEVICE_ATTR_WO(reset_protection);
118
119static struct attribute *haps_attributes[] = {
120	&dev_attr_protection_level.attr,
121	&dev_attr_reset_protection.attr,
122	NULL,
123};
124
125static const struct attribute_group haps_attr_group = {
126	.attrs = haps_attributes,
127};
128
129/*
130 * ACPI stuff
131 */
132static void toshiba_haps_notify(struct acpi_device *device, u32 event)
133{
134	pr_debug("Received event: 0x%x\n", event);
135
136	acpi_bus_generate_netlink_event(device->pnp.device_class,
137					dev_name(&device->dev),
138					event, 0);
139}
140
141static void toshiba_haps_remove(struct acpi_device *device)
142{
143	sysfs_remove_group(&device->dev.kobj, &haps_attr_group);
144
145	if (toshiba_haps)
146		toshiba_haps = NULL;
147}
148
149/* Helper function */
150static int toshiba_haps_available(acpi_handle handle)
151{
152	acpi_status status;
153	u64 hdd_present;
154
155	/*
156	 * A non existent device as well as having (only)
157	 * Solid State Drives can cause the call to fail.
158	 */
159	status = acpi_evaluate_integer(handle, "_STA", NULL, &hdd_present);
160	if (ACPI_FAILURE(status)) {
161		pr_err("ACPI call to query HDD protection failed\n");
162		return 0;
163	}
164
165	if (!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