1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * SMBus driver for ACPI Embedded Controller (v0.1)
4 *
5 * Copyright (c) 2007 Alexey Starikovskiy
6 */
7
8 #define pr_fmt(fmt) "ACPI: " fmt
9
10 #include <linux/acpi.h>
11 #include <linux/wait.h>
12 #include <linux/slab.h>
13 #include <linux/delay.h>
14 #include <linux/module.h>
15 #include <linux/interrupt.h>
16 #include "sbshc.h"
17 #include "internal.h"
18
19 #define ACPI_SMB_HC_CLASS "smbus_host_ctl"
20 #define ACPI_SMB_HC_DEVICE_NAME "ACPI SMBus HC"
21
22 struct acpi_smb_hc {
23 struct acpi_ec *ec;
24 struct mutex lock;
25 wait_queue_head_t wait;
26 u8 offset;
27 u8 query_bit;
28 smbus_alarm_callback callback;
29 void *context;
30 bool done;
31 };
32
33 static int acpi_smbus_hc_add(struct acpi_device *device);
34 static void acpi_smbus_hc_remove(struct acpi_device *device);
35
36 static const struct acpi_device_id sbs_device_ids[] = {
37 {"ACPI0001", 0},
38 {"ACPI0005", 0},
39 {"", 0},
40 };
41
42 MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
43
44 static struct acpi_driver acpi_smb_hc_driver = {
45 .name = "smbus_hc",
46 .class = ACPI_SMB_HC_CLASS,
47 .ids = sbs_device_ids,
48 .ops = {
49 .add = acpi_smbus_hc_add,
50 .remove = acpi_smbus_hc_remove,
51 },
52 };
53
54 union acpi_smb_status {
55 u8 raw;
56 struct {
57 u8 status:5;
58 u8 reserved:1;
59 u8 alarm:1;
60 u8 done:1;
61 } fields;
62 };
63
64 enum acpi_smb_status_codes {
65 SMBUS_OK = 0,
66 SMBUS_UNKNOWN_FAILURE = 0x07,
67 SMBUS_DEVICE_ADDRESS_NACK = 0x10,
68 SMBUS_DEVICE_ERROR = 0x11,
69 SMBUS_DEVICE_COMMAND_ACCESS_DENIED = 0x12,
70 SMBUS_UNKNOWN_ERROR = 0x13,
71 SMBUS_DEVICE_ACCESS_DENIED = 0x17,
72 SMBUS_TIMEOUT = 0x18,
73 SMBUS_HOST_UNSUPPORTED_PROTOCOL = 0x19,
74 SMBUS_BUSY = 0x1a,
75 SMBUS_PEC_ERROR = 0x1f,
76 };
77
78 enum acpi_smb_offset {
79 ACPI_SMB_PROTOCOL = 0, /* protocol, PEC */
80 ACPI_SMB_STATUS = 1, /* status */
81 ACPI_SMB_ADDRESS = 2, /* address */
82 ACPI_SMB_COMMAND = 3, /* command */
83 ACPI_SMB_DATA = 4, /* 32 data registers */
84 ACPI_SMB_BLOCK_COUNT = 0x24, /* number of data bytes */
85 ACPI_SMB_ALARM_ADDRESS = 0x25, /* alarm address */
86 ACPI_SMB_ALARM_DATA = 0x26, /* 2 bytes alarm data */
87 };
88
smb_hc_read(struct acpi_smb_hc * hc,u8 address,u8 * data)89 static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
90 {
91 return ec_read(hc->offset + address, data);
92 }
93
smb_hc_write(struct acpi_smb_hc * hc,u8 address,u8 data)94 static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
95 {
96 return ec_write(hc->offset + address, data);
97 }
98
wait_transaction_complete(struct acpi_smb_hc * hc,int timeout)99 static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
100 {
101 if (wait_event_timeout(hc->wait, hc->done, msecs_to_jiffies(timeout)))
102 return 0;
103 return -ETIME;
104 }
105
acpi_smbus_transaction(struct acpi_smb_hc * hc,u8 protocol,u8 address,u8 command,u8 * data,u8 length)106 static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
107 u8 address, u8 command, u8 *data, u8 length)
108 {
109 int ret = -EFAULT, i;
110 u8 temp, sz = 0;
111
112 if (!hc) {
113 pr_err("host controller is not configured\n");
114 return ret;
115 }
116
117 mutex_lock(&hc->lock);
118 hc->done = false;
119 if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
120 goto end;
121 if (temp) {
122 ret = -EBUSY;
123 goto end;
124 }
125 smb_hc_write(hc, ACPI_SMB_COMMAND, command);
126 if (!(protocol & 0x01)) {
127 smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
128 for (i = 0; i < length; ++i)
129 smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
130 }
131 smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
132 smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
133 /*
134 * Wait for completion. Save the status code, data size,
135 * and data into the return package (if required by the protocol).
136 */
137 ret = wait_transaction_complete(hc, 1000);
138 if (ret || !(protocol & 0x01))
139 goto end;
140 switch (protocol) {
141 case SMBUS_RECEIVE_BYTE:
142 case SMBUS_READ_BYTE:
143 sz = 1;
144 break;
145 case SMBUS_READ_WORD:
146 sz = 2;
147 break;
148 case SMBUS_READ_BLOCK:
149 if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
150 ret = -EFAULT;
151 goto end;
152 }
153 sz &= 0x1f;
154 break;
155 }
156 for (i = 0; i < sz; ++i)
157 smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
158 end:
159 mutex_unlock(&hc->lock);
160 return ret;
161 }
162
acpi_smbus_read(struct acpi_smb_hc * hc,u8 protocol,u8 address,u8 command,u8 * data)163 int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
164 u8 command, u8 *data)
165 {
166 return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
167 }
168
169 EXPORT_SYMBOL_GPL(acpi_smbus_read);
170
acpi_smbus_write(struct acpi_smb_hc * hc,u8 protocol,u8 address,u8 command,u8 * data,u8 length)171 int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
172 u8 command, u8 *data, u8 length)
173 {
174 return acpi_smbus_transaction(hc, protocol, address, command, data, length);
175 }
176
177 EXPORT_SYMBOL_GPL(acpi_smbus_write);
178
acpi_smbus_register_callback(struct acpi_smb_hc * hc,smbus_alarm_callback callback,void * context)179 int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
180 smbus_alarm_callback callback, void *context)
181 {
182 mutex_lock(&hc->lock);
183 hc->callback = callback;
184 hc->context = context;
185 mutex_unlock(&hc->lock);
186 return 0;
187 }
188
189 EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
190
acpi_smbus_unregister_callback(struct acpi_smb_hc * hc)191 int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
192 {
193 mutex_lock(&hc->lock);
194 hc->callback = NULL;
195 hc->context = NULL;
196 mutex_unlock(&hc->lock);
197 acpi_os_wait_events_complete();
198 return 0;
199 }
200
201 EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
202
acpi_smbus_callback(void * context)203 static inline void acpi_smbus_callback(void *context)
204 {
205 struct acpi_smb_hc *hc = context;
206 if (hc->callback)
207 hc->callback(hc->context);
208 }
209
smbus_alarm(void * context)210 static int smbus_alarm(void *context)
211 {
212 struct acpi_smb_hc *hc = context;
213 union acpi_smb_status status;
214 u8 address;
215 if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
216 return 0;
217 /* Check if it is only a completion notify */
218 if (status.fields.done && status.fields.status == SMBUS_OK) {
219 hc->done = true;
220 wake_up(&hc->wait);
221 }
222 if (!status.fields.alarm)
223 return 0;
224 mutex_lock(&hc->lock);
225 smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
226 status.fields.alarm = 0;
227 smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
228 /* We are only interested in events coming from known devices */
229 switch (address >> 1) {
230 case ACPI_SBS_CHARGER:
231 case ACPI_SBS_MANAGER:
232 case ACPI_SBS_BATTERY:
233 acpi_os_execute(OSL_NOTIFY_HANDLER,
234 acpi_smbus_callback, hc);
235 }
236 mutex_unlock(&hc->lock);
237 return 0;
238 }
239
acpi_smbus_hc_add(struct acpi_device * device)240 static int acpi_smbus_hc_add(struct acpi_device *device)
241 {
242 int status;
243 unsigned long long val;
244 struct acpi_smb_hc *hc;
245
246 if (!device)
247 return -EINVAL;
248
249 status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
250 if (ACPI_FAILURE(status)) {
251 pr_err("error obtaining _EC.\n");
252 return -EIO;
253 }
254
255 strscpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
256 strscpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
257
258 hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
259 if (!hc)
260 return -ENOMEM;
261 mutex_init(&hc->lock);
262 init_waitqueue_head(&hc->wait);
263
264 hc->ec = acpi_driver_data(acpi_dev_parent(device));
265 hc->offset = (val >> 8) & 0xff;
266 hc->query_bit = val & 0xff;
267 device->driver_data = hc;
268
269 acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
270 dev_info(&device->dev, "SBS HC: offset = 0x%0x, query_bit = 0x%0x\n",
271 hc->offset, hc->query_bit);
272
273 return 0;
274 }
275
acpi_smbus_hc_remove(struct acpi_device * device)276 static void acpi_smbus_hc_remove(struct acpi_device *device)
277 {
278 struct acpi_smb_hc *hc;
279
280 if (!device)
281 return;
282
283 hc = acpi_driver_data(device);
284 acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
285 acpi_os_wait_events_complete();
286 kfree(hc);
287 device->driver_data = NULL;
288 }
289
290 module_acpi_driver(acpi_smb_hc_driver);
291
292 MODULE_LICENSE("GPL");
293 MODULE_AUTHOR("Alexey Starikovskiy");
294 MODULE_DESCRIPTION("ACPI SMBus HC driver");
295