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 <linux/dmi.h>
18#include "sbshc.h"
19
20#define PREFIX "ACPI: "
21
22#define ACPI_SMB_HC_CLASS	"smbus_host_ctl"
23#define ACPI_SMB_HC_DEVICE_NAME	"ACPI SMBus HC"
24
25struct acpi_smb_hc {
26	struct acpi_ec *ec;
27	struct mutex lock;
28	wait_queue_head_t wait;
29	u8 offset;
30	u8 query_bit;
31	smbus_alarm_callback callback;
32	void *context;
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 bool macbook;
92
93static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
94{
95	return ec_read(hc->offset + address, data);
96}
97
98static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
99{
100	return ec_write(hc->offset + address, data);
101}
102
103static inline int smb_check_done(struct acpi_smb_hc *hc)
104{
105	union acpi_smb_status status = {.raw = 0};
106	smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw);
107	return status.fields.done && (status.fields.status == SMBUS_OK);
108}
109
110static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
111{
112	if (wait_event_timeout(hc->wait, smb_check_done(hc),
113			       msecs_to_jiffies(timeout)))
114		return 0;
115	/*
116	 * After the timeout happens, OS will try to check the status of SMbus.
117	 * If the status is what OS expected, it will be regarded as the bogus
118	 * timeout.
119	 */
120	if (smb_check_done(hc))
121		return 0;
122	else
123		return -ETIME;
124}
125
126static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
127				  u8 address, u8 command, u8 *data, u8 length)
128{
129	int ret = -EFAULT, i;
130	u8 temp, sz = 0;
131
132	if (!hc) {
133		printk(KERN_ERR PREFIX "host controller is not configured\n");
134		return ret;
135	}
136
137	mutex_lock(&hc->lock);
138	if (macbook)
139		udelay(5);
140	if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
141		goto end;
142	if (temp) {
143		ret = -EBUSY;
144		goto end;
145	}
146	smb_hc_write(hc, ACPI_SMB_COMMAND, command);
147	if (!(protocol & 0x01)) {
148		smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
149		for (i = 0; i < length; ++i)
150			smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
151	}
152	smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
153	smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
154	/*
155	 * Wait for completion. Save the status code, data size,
156	 * and data into the return package (if required by the protocol).
157	 */
158	ret = wait_transaction_complete(hc, 1000);
159	if (ret || !(protocol & 0x01))
160		goto end;
161	switch (protocol) {
162	case SMBUS_RECEIVE_BYTE:
163	case SMBUS_READ_BYTE:
164		sz = 1;
165		break;
166	case SMBUS_READ_WORD:
167		sz = 2;
168		break;
169	case SMBUS_READ_BLOCK:
170		if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
171			ret = -EFAULT;
172			goto end;
173		}
174		sz &= 0x1f;
175		break;
176	}
177	for (i = 0; i < sz; ++i)
178		smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
179      end:
180	mutex_unlock(&hc->lock);
181	return ret;
182}
183
184int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
185		    u8 command, u8 *data)
186{
187	return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
188}
189
190EXPORT_SYMBOL_GPL(acpi_smbus_read);
191
192int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
193		     u8 command, u8 *data, u8 length)
194{
195	return acpi_smbus_transaction(hc, protocol, address, command, data, length);
196}
197
198EXPORT_SYMBOL_GPL(acpi_smbus_write);
199
200int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
201			         smbus_alarm_callback callback, void *context)
202{
203	mutex_lock(&hc->lock);
204	hc->callback = callback;
205	hc->context = context;
206	mutex_unlock(&hc->lock);
207	return 0;
208}
209
210EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
211
212int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
213{
214	mutex_lock(&hc->lock);
215	hc->callback = NULL;
216	hc->context = NULL;
217	mutex_unlock(&hc->lock);
218	return 0;
219}
220
221EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
222
223static inline void acpi_smbus_callback(void *context)
224{
225	struct acpi_smb_hc *hc = context;
226	if (hc->callback)
227		hc->callback(hc->context);
228}
229
230static int smbus_alarm(void *context)
231{
232	struct acpi_smb_hc *hc = context;
233	union acpi_smb_status status;
234	u8 address;
235	if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
236		return 0;
237	/* Check if it is only a completion notify */
238	if (status.fields.done)
239		wake_up(&hc->wait);
240	if (!status.fields.alarm)
241		return 0;
242	mutex_lock(&hc->lock);
243	smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
244	status.fields.alarm = 0;
245	smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
246	/* We are only interested in events coming from known devices */
247	switch (address >> 1) {
248		case ACPI_SBS_CHARGER:
249		case ACPI_SBS_MANAGER:
250		case ACPI_SBS_BATTERY:
251			acpi_os_execute(OSL_NOTIFY_HANDLER,
252					acpi_smbus_callback, hc);
253		default:;
254	}
255	mutex_unlock(&hc->lock);
256	return 0;
257}
258
259typedef int (*acpi_ec_query_func) (void *data);
260
261extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
262			      acpi_handle handle, acpi_ec_query_func func,
263			      void *data);
264
265static int macbook_dmi_match(const struct dmi_system_id *d)
266{
267	pr_debug("Detected MacBook, enabling workaround\n");
268	macbook = true;
269	return 0;
270}
271
272static struct dmi_system_id acpi_smbus_dmi_table[] = {
273	{ macbook_dmi_match, "Apple MacBook", {
274	  DMI_MATCH(DMI_BOARD_VENDOR, "Apple"),
275	  DMI_MATCH(DMI_PRODUCT_NAME, "MacBook") },
276	},
277	{ },
278};
279
280static int acpi_smbus_hc_add(struct acpi_device *device)
281{
282	int status;
283	unsigned long long val;
284	struct acpi_smb_hc *hc;
285
286	dmi_check_system(acpi_smbus_dmi_table);
287
288	if (!device)
289		return -EINVAL;
290
291	status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
292	if (ACPI_FAILURE(status)) {
293		printk(KERN_ERR PREFIX "error obtaining _EC.\n");
294		return -EIO;
295	}
296
297	strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
298	strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
299
300	hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
301	if (!hc)
302		return -ENOMEM;
303	mutex_init(&hc->lock);
304	init_waitqueue_head(&hc->wait);
305
306	hc->ec = acpi_driver_data(device->parent);
307	hc->offset = (val >> 8) & 0xff;
308	hc->query_bit = val & 0xff;
309	device->driver_data = hc;
310
311	acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
312	printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
313		hc->ec, hc->offset, hc->query_bit);
314
315	return 0;
316}
317
318extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
319
320static int acpi_smbus_hc_remove(struct acpi_device *device)
321{
322	struct acpi_smb_hc *hc;
323
324	if (!device)
325		return -EINVAL;
326
327	hc = acpi_driver_data(device);
328	acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
329	kfree(hc);
330	device->driver_data = NULL;
331	return 0;
332}
333
334module_acpi_driver(acpi_smb_hc_driver);
335
336MODULE_LICENSE("GPL");
337MODULE_AUTHOR("Alexey Starikovskiy");
338MODULE_DESCRIPTION("ACPI SMBus HC driver");
339