xref: /openbmc/linux/drivers/acpi/sbshc.c (revision f42b3800)
1 /*
2  * SMBus driver for ACPI Embedded Controller (v0.1)
3  *
4  * Copyright (c) 2007 Alexey Starikovskiy
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 version 2.
9  */
10 
11 #include <acpi/acpi_bus.h>
12 #include <acpi/acpi_drivers.h>
13 #include <acpi/actypes.h>
14 #include <linux/wait.h>
15 #include <linux/delay.h>
16 #include <linux/interrupt.h>
17 #include "sbshc.h"
18 
19 #define ACPI_SMB_HC_CLASS	"smbus_host_controller"
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 };
31 
32 static int acpi_smbus_hc_add(struct acpi_device *device);
33 static int acpi_smbus_hc_remove(struct acpi_device *device, int type);
34 
35 static const struct acpi_device_id sbs_device_ids[] = {
36 	{"ACPI0001", 0},
37 	{"ACPI0005", 0},
38 	{"", 0},
39 };
40 
41 MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
42 
43 static struct acpi_driver acpi_smb_hc_driver = {
44 	.name = "smbus_hc",
45 	.class = ACPI_SMB_HC_CLASS,
46 	.ids = sbs_device_ids,
47 	.ops = {
48 		.add = acpi_smbus_hc_add,
49 		.remove = acpi_smbus_hc_remove,
50 		},
51 };
52 
53 union acpi_smb_status {
54 	u8 raw;
55 	struct {
56 		u8 status:5;
57 		u8 reserved:1;
58 		u8 alarm:1;
59 		u8 done:1;
60 	} fields;
61 };
62 
63 enum acpi_smb_status_codes {
64 	SMBUS_OK = 0,
65 	SMBUS_UNKNOWN_FAILURE = 0x07,
66 	SMBUS_DEVICE_ADDRESS_NACK = 0x10,
67 	SMBUS_DEVICE_ERROR = 0x11,
68 	SMBUS_DEVICE_COMMAND_ACCESS_DENIED = 0x12,
69 	SMBUS_UNKNOWN_ERROR = 0x13,
70 	SMBUS_DEVICE_ACCESS_DENIED = 0x17,
71 	SMBUS_TIMEOUT = 0x18,
72 	SMBUS_HOST_UNSUPPORTED_PROTOCOL = 0x19,
73 	SMBUS_BUSY = 0x1a,
74 	SMBUS_PEC_ERROR = 0x1f,
75 };
76 
77 enum acpi_smb_offset {
78 	ACPI_SMB_PROTOCOL = 0,	/* protocol, PEC */
79 	ACPI_SMB_STATUS = 1,	/* status */
80 	ACPI_SMB_ADDRESS = 2,	/* address */
81 	ACPI_SMB_COMMAND = 3,	/* command */
82 	ACPI_SMB_DATA = 4,	/* 32 data registers */
83 	ACPI_SMB_BLOCK_COUNT = 0x24,	/* number of data bytes */
84 	ACPI_SMB_ALARM_ADDRESS = 0x25,	/* alarm address */
85 	ACPI_SMB_ALARM_DATA = 0x26,	/* 2 bytes alarm data */
86 };
87 
88 static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
89 {
90 	return ec_read(hc->offset + address, data);
91 }
92 
93 static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
94 {
95 	return ec_write(hc->offset + address, data);
96 }
97 
98 static inline int smb_check_done(struct acpi_smb_hc *hc)
99 {
100 	union acpi_smb_status status = {.raw = 0};
101 	smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw);
102 	return status.fields.done && (status.fields.status == SMBUS_OK);
103 }
104 
105 static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
106 {
107 	if (wait_event_timeout(hc->wait, smb_check_done(hc),
108 			       msecs_to_jiffies(timeout)))
109 		return 0;
110 	else
111 		return -ETIME;
112 }
113 
114 static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
115 				  u8 address, u8 command, u8 *data, u8 length)
116 {
117 	int ret = -EFAULT, i;
118 	u8 temp, sz = 0;
119 
120 	if (!hc) {
121 		printk(KERN_ERR PREFIX "host controller is not configured\n");
122 		return ret;
123 	}
124 
125 	mutex_lock(&hc->lock);
126 	if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
127 		goto end;
128 	if (temp) {
129 		ret = -EBUSY;
130 		goto end;
131 	}
132 	smb_hc_write(hc, ACPI_SMB_COMMAND, command);
133 	if (!(protocol & 0x01)) {
134 		smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
135 		for (i = 0; i < length; ++i)
136 			smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
137 	}
138 	smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
139 	smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
140 	/*
141 	 * Wait for completion. Save the status code, data size,
142 	 * and data into the return package (if required by the protocol).
143 	 */
144 	ret = wait_transaction_complete(hc, 1000);
145 	if (ret || !(protocol & 0x01))
146 		goto end;
147 	switch (protocol) {
148 	case SMBUS_RECEIVE_BYTE:
149 	case SMBUS_READ_BYTE:
150 		sz = 1;
151 		break;
152 	case SMBUS_READ_WORD:
153 		sz = 2;
154 		break;
155 	case SMBUS_READ_BLOCK:
156 		if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
157 			ret = -EFAULT;
158 			goto end;
159 		}
160 		sz &= 0x1f;
161 		break;
162 	}
163 	for (i = 0; i < sz; ++i)
164 		smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
165       end:
166 	mutex_unlock(&hc->lock);
167 	return ret;
168 }
169 
170 int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
171 		    u8 command, u8 *data)
172 {
173 	return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
174 }
175 
176 EXPORT_SYMBOL_GPL(acpi_smbus_read);
177 
178 int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
179 		     u8 command, u8 *data, u8 length)
180 {
181 	return acpi_smbus_transaction(hc, protocol, address, command, data, length);
182 }
183 
184 EXPORT_SYMBOL_GPL(acpi_smbus_write);
185 
186 int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
187 			         smbus_alarm_callback callback, void *context)
188 {
189 	mutex_lock(&hc->lock);
190 	hc->callback = callback;
191 	hc->context = context;
192 	mutex_unlock(&hc->lock);
193 	return 0;
194 }
195 
196 EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
197 
198 int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
199 {
200 	mutex_lock(&hc->lock);
201 	hc->callback = NULL;
202 	hc->context = NULL;
203 	mutex_unlock(&hc->lock);
204 	return 0;
205 }
206 
207 EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
208 
209 static inline void acpi_smbus_callback(void *context)
210 {
211 	struct acpi_smb_hc *hc = context;
212 	if (hc->callback)
213 		hc->callback(hc->context);
214 }
215 
216 static int smbus_alarm(void *context)
217 {
218 	struct acpi_smb_hc *hc = context;
219 	union acpi_smb_status status;
220 	u8 address;
221 	if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
222 		return 0;
223 	/* Check if it is only a completion notify */
224 	if (status.fields.done)
225 		wake_up(&hc->wait);
226 	if (!status.fields.alarm)
227 		return 0;
228 	mutex_lock(&hc->lock);
229 	smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
230 	status.fields.alarm = 0;
231 	smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
232 	/* We are only interested in events coming from known devices */
233 	switch (address >> 1) {
234 		case ACPI_SBS_CHARGER:
235 		case ACPI_SBS_MANAGER:
236 		case ACPI_SBS_BATTERY:
237 			acpi_os_execute(OSL_GPE_HANDLER,
238 					acpi_smbus_callback, hc);
239 		default:;
240 	}
241 	mutex_unlock(&hc->lock);
242 	return 0;
243 }
244 
245 typedef int (*acpi_ec_query_func) (void *data);
246 
247 extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
248 			      acpi_handle handle, acpi_ec_query_func func,
249 			      void *data);
250 
251 static int acpi_smbus_hc_add(struct acpi_device *device)
252 {
253 	int status;
254 	unsigned long val;
255 	struct acpi_smb_hc *hc;
256 
257 	if (!device)
258 		return -EINVAL;
259 
260 	status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
261 	if (ACPI_FAILURE(status)) {
262 		printk(KERN_ERR PREFIX "error obtaining _EC.\n");
263 		return -EIO;
264 	}
265 
266 	strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
267 	strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
268 
269 	hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
270 	if (!hc)
271 		return -ENOMEM;
272 	mutex_init(&hc->lock);
273 	init_waitqueue_head(&hc->wait);
274 
275 	hc->ec = acpi_driver_data(device->parent);
276 	hc->offset = (val >> 8) & 0xff;
277 	hc->query_bit = val & 0xff;
278 	acpi_driver_data(device) = hc;
279 
280 	acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
281 	printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
282 		hc->ec, hc->offset, hc->query_bit);
283 
284 	return 0;
285 }
286 
287 extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
288 
289 static int acpi_smbus_hc_remove(struct acpi_device *device, int type)
290 {
291 	struct acpi_smb_hc *hc;
292 
293 	if (!device)
294 		return -EINVAL;
295 
296 	hc = acpi_driver_data(device);
297 	acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
298 	kfree(hc);
299 	acpi_driver_data(device) = NULL;
300 	return 0;
301 }
302 
303 static int __init acpi_smb_hc_init(void)
304 {
305 	int result;
306 
307 	result = acpi_bus_register_driver(&acpi_smb_hc_driver);
308 	if (result < 0)
309 		return -ENODEV;
310 	return 0;
311 }
312 
313 static void __exit acpi_smb_hc_exit(void)
314 {
315 	acpi_bus_unregister_driver(&acpi_smb_hc_driver);
316 }
317 
318 module_init(acpi_smb_hc_init);
319 module_exit(acpi_smb_hc_exit);
320 
321 MODULE_LICENSE("GPL");
322 MODULE_AUTHOR("Alexey Starikovskiy");
323 MODULE_DESCRIPTION("ACPI SMBus HC driver");
324