drivers/i2c/busses/i2c-scmi.c

   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
  21 ACPI_MODULE_NAME("smbus_cmi");
  22
  23 struct smbus_methods_t {
  24         char *mt_info;
  25         char *mt_sbr;
  26         char *mt_sbw;
  27 };
  28
  29 struct 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
  38 static 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 */
  45 static const struct smbus_methods_t ibm_smbus_methods = {
  46         .mt_info = "SBI_",
  47         .mt_sbr  = "SBR_",
  48         .mt_sbw  = "SBW_",
  49 };
  50
  51 static 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 };
  57 MODULE_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
  80 static int
  81 acpi_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
 265 out:
 266         kfree(buffer.pointer);
 267         dev_dbg(&adap->dev, "Transaction status: %i\n", result);
 268         return result;
 269 }
 270
 271 static 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
 294 static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
 295         .smbus_xfer = acpi_smbus_cmi_access,
 296         .functionality = acpi_smbus_cmi_func,
 297 };
 298
 299
 300 static 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
 347 static 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
 363 static 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
 411 err:
 412         kfree(smbus_cmi);
 413         device->driver_data = NULL;
 414         return ret;
 415 }
 416
 417 static 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
 428 static 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 };
 437 module_acpi_driver(acpi_smbus_cmi_driver);
 438
 439 MODULE_LICENSE("GPL");
 440 MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
 441 MODULE_DESCRIPTION("ACPI SMBus CMI driver");