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 <linux/acpi.h>
12#include <linux/wait.h>
13#include <linux/slab.h>
14#include <linux/delay.h>
15#include <linux/module.h>
16#include <linux/interrupt.h>
17#include "sbshc.h"
18
19#define PREFIX "ACPI: "
20
21#define ACPI_SMB_HC_CLASS	"smbus_host_ctl"
22#define ACPI_SMB_HC_DEVICE_NAME	"ACPI SMBus HC"
23
24struct acpi_smb_hc {
25	struct acpi_ec *ec;
26	struct mutex lock;
27	wait_queue_head_t wait;
28	u8 offset;
29	u8 query_bit;
30	smbus_alarm_callback callback;
31	void *context;
32	bool done;
33};
34
35static int acpi_smbus_hc_add(struct acpi_device *device);
36static int acpi_smbus_hc_remove(struct acpi_device *device);
37
38static const struct acpi_device_id sbs_device_ids[] = {
39	{"ACPI0001", 0},
40	{"ACPI0005", 0},
41	{"", 0},
42};
43
44MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
45
46static struct acpi_driver acpi_smb_hc_driver = {
47	.name = "smbus_hc",
48	.class = ACPI_SMB_HC_CLASS,
49	.ids = sbs_device_ids,
50	.ops = {
51		.add = acpi_smbus_hc_add,
52		.remove = acpi_smbus_hc_remove,
53		},
54};
55
56union acpi_smb_status {
57	u8 raw;
58	struct {
59		u8 status:5;
60		u8 reserved:1;
61		u8 alarm:1;
62		u8 done:1;
63	} fields;
64};
65
66enum acpi_smb_status_codes {
67	SMBUS_OK = 0,
68	SMBUS_UNKNOWN_FAILURE = 0x07,
69	SMBUS_DEVICE_ADDRESS_NACK = 0x10,
70	SMBUS_DEVICE_ERROR = 0x11,
71	SMBUS_DEVICE_COMMAND_ACCESS_DENIED = 0x12,
72	SMBUS_UNKNOWN_ERROR = 0x13,
73	SMBUS_DEVICE_ACCESS_DENIED = 0x17,
74	SMBUS_TIMEOUT = 0x18,
75	SMBUS_HOST_UNSUPPORTED_PROTOCOL = 0x19,
76	SMBUS_BUSY = 0x1a,
77	SMBUS_PEC_ERROR = 0x1f,
78};
79
80enum acpi_smb_offset {
81	ACPI_SMB_PROTOCOL = 0,	/* protocol, PEC */
82	ACPI_SMB_STATUS = 1,	/* status */
83	ACPI_SMB_ADDRESS = 2,	/* address */
84	ACPI_SMB_COMMAND = 3,	/* command */
85	ACPI_SMB_DATA = 4,	/* 32 data registers */
86	ACPI_SMB_BLOCK_COUNT = 0x24,	/* number of data bytes */
87	ACPI_SMB_ALARM_ADDRESS = 0x25,	/* alarm address */
88	ACPI_SMB_ALARM_DATA = 0x26,	/* 2 bytes alarm data */
89};
90
91static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
92{
93	return ec_read(hc->offset + address, data);
94}
95
96static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
97{
98	return ec_write(hc->offset + address, data);
99}
100
101static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
102{
103	if (wait_event_timeout(hc->wait, hc->done, msecs_to_jiffies(timeout)))
104		return 0;
105	return -ETIME;
106}
107
108static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
109				  u8 address, u8 command, u8 *data, u8 length)
110{
111	int ret = -EFAULT, i;
112	u8 temp, sz = 0;
113
114	if (!hc) {
115		printk(KERN_ERR PREFIX "host controller is not configured\n");
116		return ret;
117	}
118
119	mutex_lock(&hc->lock);
120	hc->done = false;
121	if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
122		goto end;
123	if (temp) {
124		ret = -EBUSY;
125		goto end;
126	}
127	smb_hc_write(hc, ACPI_SMB_COMMAND, command);
128	if (!(protocol & 0x01)) {
129		smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
130		for (i = 0; i < length; ++i)
131			smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
132	}
133	smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
134	smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
135	/*
136	 * Wait for completion. Save the status code, data size,
137	 * and data into the return package (if required by the protocol).
138	 */
139	ret = wait_transaction_complete(hc, 1000);
140	if (ret || !(protocol & 0x01))
141		goto end;
142	switch (protocol) {
143	case SMBUS_RECEIVE_BYTE:
144	case SMBUS_READ_BYTE:
145		sz = 1;
146		break;
147	case SMBUS_READ_WORD:
148		sz = 2;
149		break;
150	case SMBUS_READ_BLOCK:
151		if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
152			ret = -EFAULT;
153			goto end;
154		}
155		sz &= 0x1f;
156		break;
157	}
158	for (i = 0; i < sz; ++i)
159		smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
160      end:
161	mutex_unlock(&hc->lock);
162	return ret;
163}
164
165int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
166		    u8 command, u8 *data)
167{
168	return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
169}
170
171EXPORT_SYMBOL_GPL(acpi_smbus_read);
172
173int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
174		     u8 command, u8 *data, u8 length)
175{
176	return acpi_smbus_transaction(hc, protocol, address, command, data, length);
177}
178
179EXPORT_SYMBOL_GPL(acpi_smbus_write);
180
181int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
182			         smbus_alarm_callback callback, void *context)
183{
184	mutex_lock(&hc->lock);
185	hc->callback = callback;
186	hc->context = context;
187	mutex_unlock(&hc->lock);
188	return 0;
189}
190
191EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
192
193int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
194{
195	mutex_lock(&hc->lock);
196	hc->callback = NULL;
197	hc->context = NULL;
198	mutex_unlock(&hc->lock);
199	return 0;
200}
201
202EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
203
204static inline void acpi_smbus_callback(void *context)
205{
206	struct acpi_smb_hc *hc = context;
207	if (hc->callback)
208		hc->callback(hc->context);
209}
210
211static int smbus_alarm(void *context)
212{
213	struct acpi_smb_hc *hc = context;
214	union acpi_smb_status status;
215	u8 address;
216	if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
217		return 0;
218	/* Check if it is only a completion notify */
219	if (status.fields.done && status.fields.status == SMBUS_OK) {
220		hc->done = true;
221		wake_up(&hc->wait);
222	}
223	if (!status.fields.alarm)
224		return 0;
225	mutex_lock(&hc->lock);
226	smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
227	status.fields.alarm = 0;
228	smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
229	/* We are only interested in events coming from known devices */
230	switch (address >> 1) {
231		case ACPI_SBS_CHARGER:
232		case ACPI_SBS_MANAGER:
233		case ACPI_SBS_BATTERY:
234			acpi_os_execute(OSL_NOTIFY_HANDLER,
235					acpi_smbus_callback, hc);
236		default:;
237	}
238	mutex_unlock(&hc->lock);
239	return 0;
240}
241
242typedef int (*acpi_ec_query_func) (void *data);
243
244extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
245			      acpi_handle handle, acpi_ec_query_func func,
246			      void *data);
247
248static int acpi_smbus_hc_add(struct acpi_device *device)
249{
250	int status;
251	unsigned long long val;
252	struct acpi_smb_hc *hc;
253
254	if (!device)
255		return -EINVAL;
256
257	status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
258	if (ACPI_FAILURE(status)) {
259		printk(KERN_ERR PREFIX "error obtaining _EC.\n");
260		return -EIO;
261	}
262
263	strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
264	strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
265
266	hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
267	if (!hc)
268		return -ENOMEM;
269	mutex_init(&hc->lock);
270	init_waitqueue_head(&hc->wait);
271
272	hc->ec = acpi_driver_data(device->parent);
273	hc->offset = (val >> 8) & 0xff;
274	hc->query_bit = val & 0xff;
275	device->driver_data = hc;
276
277	acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
278	printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
279		hc->ec, hc->offset, hc->query_bit);
280
281	return 0;
282}
283
284extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
285
286static int acpi_smbus_hc_remove(struct acpi_device *device)
287{
288	struct acpi_smb_hc *hc;
289
290	if (!device)
291		return -EINVAL;
292
293	hc = acpi_driver_data(device);
294	acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
295	kfree(hc);
296	device->driver_data = NULL;
297	return 0;
298}
299
300module_acpi_driver(acpi_smb_hc_driver);
301
302MODULE_LICENSE("GPL");
303MODULE_AUTHOR("Alexey Starikovskiy");
304MODULE_DESCRIPTION("ACPI SMBus HC driver");
305