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