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(object: smbus_cmi->handle, pathname: method, parameter_objects: &input,
174 return_object_buffer: &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(objp: 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(object: smbus_cmi->handle,
303 pathname: smbus_cmi->methods->mt_info,
304 NULL, return_object_buffer: &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(objp: 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(objp: 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(objp: 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(object: handle, ACPI_SINGLE_NAME, ret_path_ptr: &buffer);
349
350 if (ACPI_SUCCESS(status))
351 acpi_smbus_cmi_add_cap(smbus_cmi, name: 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(pdev: device, data: 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, start_object: smbus_cmi->handle, max_depth: 1,
376 descending_callback: acpi_smbus_cmi_query_methods, NULL, context: smbus_cmi, NULL);
377
378 if (smbus_cmi->cap_info == 0) {
379 ret = -ENODEV;
380 goto err;
381 }
382
383 snprintf(buf: smbus_cmi->adapter.name, size: sizeof(smbus_cmi->adapter.name),
384 fmt: "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;
389 smbus_cmi->adapter.dev.parent = &device->dev;
390
391 ret = i2c_add_adapter(adap: &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(objp: 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(pdev: device);
407
408 i2c_del_adapter(adap: &smbus_cmi->adapter);
409 kfree(objp: smbus_cmi);
410}
411
412static struct platform_driver smbus_cmi_driver = {
413 .probe = smbus_cmi_probe,
414 .remove = 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

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source code of linux/drivers/i2c/busses/i2c-scmi.c