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