1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * SMBus driver for ACPI SMBus CMI
4 *
5 * Copyright (C) 2009 Crane Cai <crane.cai@amd.com>
6 */
7
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/kernel.h>
11#include <linux/stddef.h>
12#include <linux/i2c.h>
13#include <linux/acpi.h>
14
15#define ACPI_SMBUS_HC_CLASS		"smbus"
16#define ACPI_SMBUS_HC_DEVICE_NAME	"cmi"
17
18/* SMBUS HID definition as supported by Microsoft Windows */
19#define ACPI_SMBUS_MS_HID		"SMB0001"
20
21ACPI_MODULE_NAME("smbus_cmi");
22
23struct smbus_methods_t {
24	char *mt_info;
25	char *mt_sbr;
26	char *mt_sbw;
27};
28
29struct acpi_smbus_cmi {
30	acpi_handle handle;
31	struct i2c_adapter adapter;
32	u8 cap_info:1;
33	u8 cap_read:1;
34	u8 cap_write:1;
35	struct smbus_methods_t *methods;
36};
37
38static const struct smbus_methods_t smbus_methods = {
39	.mt_info = "_SBI",
40	.mt_sbr  = "_SBR",
41	.mt_sbw  = "_SBW",
42};
43
44/* Some IBM BIOSes omit the leading underscore */
45static const struct smbus_methods_t ibm_smbus_methods = {
46	.mt_info = "SBI_",
47	.mt_sbr  = "SBR_",
48	.mt_sbw  = "SBW_",
49};
50
51static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
52	{"SMBUS01", (kernel_ulong_t)&smbus_methods},
53	{ACPI_SMBUS_IBM_HID, (kernel_ulong_t)&ibm_smbus_methods},
54	{ACPI_SMBUS_MS_HID, (kernel_ulong_t)&smbus_methods},
55	{"", 0}
56};
57MODULE_DEVICE_TABLE(acpi, acpi_smbus_cmi_ids);
58
59#define ACPI_SMBUS_STATUS_OK			0x00
60#define ACPI_SMBUS_STATUS_FAIL			0x07
61#define ACPI_SMBUS_STATUS_DNAK			0x10
62#define ACPI_SMBUS_STATUS_DERR			0x11
63#define ACPI_SMBUS_STATUS_CMD_DENY		0x12
64#define ACPI_SMBUS_STATUS_UNKNOWN		0x13
65#define ACPI_SMBUS_STATUS_ACC_DENY		0x17
66#define ACPI_SMBUS_STATUS_TIMEOUT		0x18
67#define ACPI_SMBUS_STATUS_NOTSUP		0x19
68#define ACPI_SMBUS_STATUS_BUSY			0x1a
69#define ACPI_SMBUS_STATUS_PEC			0x1f
70
71#define ACPI_SMBUS_PRTCL_WRITE			0x00
72#define ACPI_SMBUS_PRTCL_READ			0x01
73#define ACPI_SMBUS_PRTCL_QUICK			0x02
74#define ACPI_SMBUS_PRTCL_BYTE			0x04
75#define ACPI_SMBUS_PRTCL_BYTE_DATA		0x06
76#define ACPI_SMBUS_PRTCL_WORD_DATA		0x08
77#define ACPI_SMBUS_PRTCL_BLOCK_DATA		0x0a
78
79
80static int
81acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
82		   char read_write, u8 command, int size,
83		   union i2c_smbus_data *data)
84{
85	int result = 0;
86	struct acpi_smbus_cmi *smbus_cmi = adap->algo_data;
87	unsigned char protocol;
88	acpi_status status = 0;
89	struct acpi_object_list input;
90	union acpi_object mt_params[5];
91	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
92	union acpi_object *obj;
93	union acpi_object *pkg;
94	char *method;
95	int len = 0;
96
97	dev_dbg(&adap->dev, "access size: %d %s\n", size,
98		(read_write) ? "READ" : "WRITE");
99	switch (size) {
100	case I2C_SMBUS_QUICK:
101		protocol = ACPI_SMBUS_PRTCL_QUICK;
102		command = 0;
103		if (read_write == I2C_SMBUS_WRITE) {
104			mt_params[3].type = ACPI_TYPE_INTEGER;
105			mt_params[3].integer.value = 0;
106			mt_params[4].type = ACPI_TYPE_INTEGER;
107			mt_params[4].integer.value = 0;
108		}
109		break;
110
111	case I2C_SMBUS_BYTE:
112		protocol = ACPI_SMBUS_PRTCL_BYTE;
113		if (read_write == I2C_SMBUS_WRITE) {
114			mt_params[3].type = ACPI_TYPE_INTEGER;
115			mt_params[3].integer.value = 0;
116			mt_params[4].type = ACPI_TYPE_INTEGER;
117			mt_params[4].integer.value = 0;
118		} else {
119			command = 0;
120		}
121		break;
122
123	case I2C_SMBUS_BYTE_DATA:
124		protocol = ACPI_SMBUS_PRTCL_BYTE_DATA;
125		if (read_write == I2C_SMBUS_WRITE) {
126			mt_params[3].type = ACPI_TYPE_INTEGER;
127			mt_params[3].integer.value = 1;
128			mt_params[4].type = ACPI_TYPE_INTEGER;
129			mt_params[4].integer.value = data->byte;
130		}
131		break;
132
133	case I2C_SMBUS_WORD_DATA:
134		protocol = ACPI_SMBUS_PRTCL_WORD_DATA;
135		if (read_write == I2C_SMBUS_WRITE) {
136			mt_params[3].type = ACPI_TYPE_INTEGER;
137			mt_params[3].integer.value = 2;
138			mt_params[4].type = ACPI_TYPE_INTEGER;
139			mt_params[4].integer.value = data->word;
140		}
141		break;
142
143	case I2C_SMBUS_BLOCK_DATA:
144		protocol = ACPI_SMBUS_PRTCL_BLOCK_DATA;
145		if (read_write == I2C_SMBUS_WRITE) {
146			len = data->block[0];
147			if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
148				return -EINVAL;
149			mt_params[3].type = ACPI_TYPE_INTEGER;
150			mt_params[3].integer.value = len;
151			mt_params[4].type = ACPI_TYPE_BUFFER;
152			mt_params[4].buffer.length = len;
153			mt_params[4].buffer.pointer = data->block + 1;
154		}
155		break;
156
157	default:
158		dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
159		return -EOPNOTSUPP;
160	}
161
162	if (read_write == I2C_SMBUS_READ) {
163		protocol |= ACPI_SMBUS_PRTCL_READ;
164		method = smbus_cmi->methods->mt_sbr;
165		input.count = 3;
166	} else {
167		protocol |= ACPI_SMBUS_PRTCL_WRITE;
168		method = smbus_cmi->methods->mt_sbw;
169		input.count = 5;
170	}
171
172	input.pointer = mt_params;
173	mt_params[0].type = ACPI_TYPE_INTEGER;
174	mt_params[0].integer.value = protocol;
175	mt_params[1].type = ACPI_TYPE_INTEGER;
176	mt_params[1].integer.value = addr;
177	mt_params[2].type = ACPI_TYPE_INTEGER;
178	mt_params[2].integer.value = command;
179
180	status = acpi_evaluate_object(smbus_cmi->handle, method, &input,
181				      &buffer);
182	if (ACPI_FAILURE(status)) {
183		acpi_handle_err(smbus_cmi->handle,
184				"Failed to evaluate %s: %i\n", method, status);
185		return -EIO;
186	}
187
188	pkg = buffer.pointer;
189	if (pkg && pkg->type == ACPI_TYPE_PACKAGE)
190		obj = pkg->package.elements;
191	else {
192		acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
193		result = -EIO;
194		goto out;
195	}
196	if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
197		acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
198		result = -EIO;
199		goto out;
200	}
201
202	result = obj->integer.value;
203	acpi_handle_debug(smbus_cmi->handle,  "%s return status: %i\n", method,
204			  result);
205
206	switch (result) {
207	case ACPI_SMBUS_STATUS_OK:
208		result = 0;
209		break;
210	case ACPI_SMBUS_STATUS_BUSY:
211		result = -EBUSY;
212		goto out;
213	case ACPI_SMBUS_STATUS_TIMEOUT:
214		result = -ETIMEDOUT;
215		goto out;
216	case ACPI_SMBUS_STATUS_DNAK:
217		result = -ENXIO;
218		goto out;
219	default:
220		result = -EIO;
221		goto out;
222	}
223
224	if (read_write == I2C_SMBUS_WRITE || size == I2C_SMBUS_QUICK)
225		goto out;
226
227	obj = pkg->package.elements + 1;
228	if (obj->type != ACPI_TYPE_INTEGER) {
229		acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
230		result = -EIO;
231		goto out;
232	}
233
234	len = obj->integer.value;
235	obj = pkg->package.elements + 2;
236	switch (size) {
237	case I2C_SMBUS_BYTE:
238	case I2C_SMBUS_BYTE_DATA:
239	case I2C_SMBUS_WORD_DATA:
240		if (obj->type != ACPI_TYPE_INTEGER) {
241			acpi_handle_err(smbus_cmi->handle,
242					"Invalid argument type\n");
243			result = -EIO;
244			goto out;
245		}
246		if (len == 2)
247			data->word = obj->integer.value;
248		else
249			data->byte = obj->integer.value;
250		break;
251	case I2C_SMBUS_BLOCK_DATA:
252		if (obj->type != ACPI_TYPE_BUFFER) {
253			acpi_handle_err(smbus_cmi->handle,
254					"Invalid argument type\n");
255			result = -EIO;
256			goto out;
257		}
258		if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
259			return -EPROTO;
260		data->block[0] = len;
261		memcpy(data->block + 1, obj->buffer.pointer, len);
262		break;
263	}
264
265out:
266	kfree(buffer.pointer);
267	dev_dbg(&adap->dev, "Transaction status: %i\n", result);
268	return result;
269}
270
271static u32 acpi_smbus_cmi_func(struct i2c_adapter *adapter)
272{
273	struct acpi_smbus_cmi *smbus_cmi = adapter->algo_data;
274	u32 ret;
275
276	ret = smbus_cmi->cap_read | smbus_cmi->cap_write ?
277		I2C_FUNC_SMBUS_QUICK : 0;
278
279	ret |= smbus_cmi->cap_read ?
280		(I2C_FUNC_SMBUS_READ_BYTE |
281		I2C_FUNC_SMBUS_READ_BYTE_DATA |
282		I2C_FUNC_SMBUS_READ_WORD_DATA |
283		I2C_FUNC_SMBUS_READ_BLOCK_DATA) : 0;
284
285	ret |= smbus_cmi->cap_write ?
286		(I2C_FUNC_SMBUS_WRITE_BYTE |
287		I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
288		I2C_FUNC_SMBUS_WRITE_WORD_DATA |
289		I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) : 0;
290
291	return ret;
292}
293
294static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
295	.smbus_xfer = acpi_smbus_cmi_access,
296	.functionality = acpi_smbus_cmi_func,
297};
298
299
300static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
301				  const char *name)
302{
303	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
304	struct acpi_handle *handle = smbus_cmi->handle;
305	union acpi_object *obj;
306	acpi_status status;
307
308	if (!strcmp(name, smbus_cmi->methods->mt_info)) {
309		status = acpi_evaluate_object(smbus_cmi->handle,
310					smbus_cmi->methods->mt_info,
311					NULL, &buffer);
312		if (ACPI_FAILURE(status)) {
313			acpi_handle_err(handle, "Failed to evaluate %s: %i\n",
314					smbus_cmi->methods->mt_info, status);
315			return -EIO;
316		}
317
318		obj = buffer.pointer;
319		if (obj && obj->type == ACPI_TYPE_PACKAGE)
320			obj = obj->package.elements;
321		else {
322			acpi_handle_err(handle, "Invalid argument type\n");
323			kfree(buffer.pointer);
324			return -EIO;
325		}
326
327		if (obj->type != ACPI_TYPE_INTEGER) {
328			acpi_handle_err(handle, "Invalid argument type\n");
329			kfree(buffer.pointer);
330			return -EIO;
331		} else
332			acpi_handle_debug(handle, "SMBus CMI Version %x\n",
333					  (int)obj->integer.value);
334
335		kfree(buffer.pointer);
336		smbus_cmi->cap_info = 1;
337	} else if (!strcmp(name, smbus_cmi->methods->mt_sbr))
338		smbus_cmi->cap_read = 1;
339	else if (!strcmp(name, smbus_cmi->methods->mt_sbw))
340		smbus_cmi->cap_write = 1;
341	else
342		acpi_handle_debug(handle, "Unsupported CMI method: %s\n", name);
343
344	return 0;
345}
346
347static acpi_status acpi_smbus_cmi_query_methods(acpi_handle handle, u32 level,
348			void *context, void **return_value)
349{
350	char node_name[5];
351	struct acpi_buffer buffer = { sizeof(node_name), node_name };
352	struct acpi_smbus_cmi *smbus_cmi = context;
353	acpi_status status;
354
355	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
356
357	if (ACPI_SUCCESS(status))
358		acpi_smbus_cmi_add_cap(smbus_cmi, node_name);
359
360	return AE_OK;
361}
362
363static int acpi_smbus_cmi_add(struct acpi_device *device)
364{
365	struct acpi_smbus_cmi *smbus_cmi;
366	const struct acpi_device_id *id;
367	int ret;
368
369	smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
370	if (!smbus_cmi)
371		return -ENOMEM;
372
373	smbus_cmi->handle = device->handle;
374	strcpy(acpi_device_name(device), ACPI_SMBUS_HC_DEVICE_NAME);
375	strcpy(acpi_device_class(device), ACPI_SMBUS_HC_CLASS);
376	device->driver_data = smbus_cmi;
377	smbus_cmi->cap_info = 0;
378	smbus_cmi->cap_read = 0;
379	smbus_cmi->cap_write = 0;
380
381	for (id = acpi_smbus_cmi_ids; id->id[0]; id++)
382		if (!strcmp(id->id, acpi_device_hid(device)))
383			smbus_cmi->methods =
384				(struct smbus_methods_t *) id->driver_data;
385
386	acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
387			    acpi_smbus_cmi_query_methods, NULL, smbus_cmi, NULL);
388
389	if (smbus_cmi->cap_info == 0) {
390		ret = -ENODEV;
391		goto err;
392	}
393
394	snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
395		"SMBus CMI adapter %s",
396		acpi_device_name(device));
397	smbus_cmi->adapter.owner = THIS_MODULE;
398	smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
399	smbus_cmi->adapter.algo_data = smbus_cmi;
400	smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
401	smbus_cmi->adapter.dev.parent = &device->dev;
402
403	ret = i2c_add_adapter(&smbus_cmi->adapter);
404	if (ret) {
405		dev_err(&device->dev, "Couldn't register adapter!\n");
406		goto err;
407	}
408
409	return 0;
410
411err:
412	kfree(smbus_cmi);
413	device->driver_data = NULL;
414	return ret;
415}
416
417static int acpi_smbus_cmi_remove(struct acpi_device *device)
418{
419	struct acpi_smbus_cmi *smbus_cmi = acpi_driver_data(device);
420
421	i2c_del_adapter(&smbus_cmi->adapter);
422	kfree(smbus_cmi);
423	device->driver_data = NULL;
424
425	return 0;
426}
427
428static struct acpi_driver acpi_smbus_cmi_driver = {
429	.name = ACPI_SMBUS_HC_DEVICE_NAME,
430	.class = ACPI_SMBUS_HC_CLASS,
431	.ids = acpi_smbus_cmi_ids,
432	.ops = {
433		.add = acpi_smbus_cmi_add,
434		.remove = acpi_smbus_cmi_remove,
435	},
436};
437module_acpi_driver(acpi_smbus_cmi_driver);
438
439MODULE_LICENSE("GPL");
440MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
441MODULE_DESCRIPTION("ACPI SMBus CMI driver");
442