drivers/i2c/busses/i2c-scmi.c

   1 /*
   2  * SMBus driver for ACPI SMBus CMI
   3  *
   4  * Copyright (C) 2009 Crane Cai <crane.cai@amd.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation version 2.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/kernel.h>
  14 #include <linux/stddef.h>
  15 #include <linux/init.h>
  16 #include <linux/i2c.h>
  17 #include <linux/acpi.h>
  18
  19 #define ACPI_SMBUS_HC_CLASS             "smbus"
  20 #define ACPI_SMBUS_HC_DEVICE_NAME       "cmi"
  21
  22 ACPI_MODULE_NAME("smbus_cmi");
  23
  24 struct smbus_methods_t {
  25         char *mt_info;
  26         char *mt_sbr;
  27         char *mt_sbw;
  28 };
  29
  30 struct acpi_smbus_cmi {
  31         acpi_handle handle;
  32         struct i2c_adapter adapter;
  33         u8 cap_info:1;
  34         u8 cap_read:1;
  35         u8 cap_write:1;
  36         struct smbus_methods_t *methods;
  37 };
  38
  39 static const struct smbus_methods_t smbus_methods = {
  40         .mt_info = "_SBI",
  41         .mt_sbr  = "_SBR",
  42         .mt_sbw  = "_SBW",
  43 };
  44
  45 /* Some IBM BIOSes omit the leading underscore */
  46 static const struct smbus_methods_t ibm_smbus_methods = {
  47         .mt_info = "SBI_",
  48         .mt_sbr  = "SBR_",
  49         .mt_sbw  = "SBW_",
  50 };
  51
  52 static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
  53         {"SMBUS01", (kernel_ulong_t)&smbus_methods},
  54         {ACPI_SMBUS_IBM_HID, (kernel_ulong_t)&ibm_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.pointer = data->block + 1;
 153                 }
 154                 break;
 155
 156         default:
 157                 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 158                 return -EOPNOTSUPP;
 159         }
 160
 161         if (read_write == I2C_SMBUS_READ) {
 162                 protocol |= ACPI_SMBUS_PRTCL_READ;
 163                 method = smbus_cmi->methods->mt_sbr;
 164                 input.count = 3;
 165         } else {
 166                 protocol |= ACPI_SMBUS_PRTCL_WRITE;
 167                 method = smbus_cmi->methods->mt_sbw;
 168                 input.count = 5;
 169         }
 170
 171         input.pointer = mt_params;
 172         mt_params[0].type = ACPI_TYPE_INTEGER;
 173         mt_params[0].integer.value = protocol;
 174         mt_params[1].type = ACPI_TYPE_INTEGER;
 175         mt_params[1].integer.value = addr;
 176         mt_params[2].type = ACPI_TYPE_INTEGER;
 177         mt_params[2].integer.value = command;
 178
 179         status = acpi_evaluate_object(smbus_cmi->handle, method, &input,
 180                                       &buffer);
 181         if (ACPI_FAILURE(status)) {
 182                 ACPI_ERROR((AE_INFO, "Evaluating %s: %i", method, status));
 183                 return -EIO;
 184         }
 185
 186         pkg = buffer.pointer;
 187         if (pkg && pkg->type == ACPI_TYPE_PACKAGE)
 188                 obj = pkg->package.elements;
 189         else {
 190                 ACPI_ERROR((AE_INFO, "Invalid argument type"));
 191                 result = -EIO;
 192                 goto out;
 193         }
 194         if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 195                 ACPI_ERROR((AE_INFO, "Invalid argument type"));
 196                 result = -EIO;
 197                 goto out;
 198         }
 199
 200         result = obj->integer.value;
 201         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s return status: %i\n",
 202                           method, result));
 203
 204         switch (result) {
 205         case ACPI_SMBUS_STATUS_OK:
 206                 result = 0;
 207                 break;
 208         case ACPI_SMBUS_STATUS_BUSY:
 209                 result = -EBUSY;
 210                 goto out;
 211         case ACPI_SMBUS_STATUS_TIMEOUT:
 212                 result = -ETIMEDOUT;
 213                 goto out;
 214         case ACPI_SMBUS_STATUS_DNAK:
 215                 result = -ENXIO;
 216                 goto out;
 217         default:
 218                 result = -EIO;
 219                 goto out;
 220         }
 221
 222         if (read_write == I2C_SMBUS_WRITE || size == I2C_SMBUS_QUICK)
 223                 goto out;
 224
 225         obj = pkg->package.elements + 1;
 226         if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 227                 ACPI_ERROR((AE_INFO, "Invalid argument type"));
 228                 result = -EIO;
 229                 goto out;
 230         }
 231
 232         len = obj->integer.value;
 233         obj = pkg->package.elements + 2;
 234         switch (size) {
 235         case I2C_SMBUS_BYTE:
 236         case I2C_SMBUS_BYTE_DATA:
 237         case I2C_SMBUS_WORD_DATA:
 238                 if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 239                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 240                         result = -EIO;
 241                         goto out;
 242                 }
 243                 if (len == 2)
 244                         data->word = obj->integer.value;
 245                 else
 246                         data->byte = obj->integer.value;
 247                 break;
 248         case I2C_SMBUS_BLOCK_DATA:
 249                 if (obj == NULL || obj->type != ACPI_TYPE_BUFFER) {
 250                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 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
 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
 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         union acpi_object *obj;
 301         acpi_status status;
 302
 303         if (!strcmp(name, smbus_cmi->methods->mt_info)) {
 304                 status = acpi_evaluate_object(smbus_cmi->handle,
 305                                         smbus_cmi->methods->mt_info,
 306                                         NULL, &buffer);
 307                 if (ACPI_FAILURE(status)) {
 308                         ACPI_ERROR((AE_INFO, "Evaluating %s: %i",
 309                                    smbus_cmi->methods->mt_info, status));
 310                         return -EIO;
 311                 }
 312
 313                 obj = buffer.pointer;
 314                 if (obj && obj->type == ACPI_TYPE_PACKAGE)
 315                         obj = obj->package.elements;
 316                 else {
 317                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 318                         kfree(buffer.pointer);
 319                         return -EIO;
 320                 }
 321
 322                 if (obj->type != ACPI_TYPE_INTEGER) {
 323                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 324                         kfree(buffer.pointer);
 325                         return -EIO;
 326                 } else
 327                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "SMBus CMI Version %x"
 328                                           "\n", (int)obj->integer.value));
 329
 330                 kfree(buffer.pointer);
 331                 smbus_cmi->cap_info = 1;
 332         } else if (!strcmp(name, smbus_cmi->methods->mt_sbr))
 333                 smbus_cmi->cap_read = 1;
 334         else if (!strcmp(name, smbus_cmi->methods->mt_sbw))
 335                 smbus_cmi->cap_write = 1;
 336         else
 337                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Unsupported CMI method: %s\n",
 338                                  name));
 339
 340         return 0;
 341 }
 342
 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
 359 static int acpi_smbus_cmi_add(struct acpi_device *device)
 360 {
 361         struct acpi_smbus_cmi *smbus_cmi;
 362         const struct acpi_device_id *id;
 363
 364         smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
 365         if (!smbus_cmi)
 366                 return -ENOMEM;
 367
 368         smbus_cmi->handle = device->handle;
 369         strcpy(acpi_device_name(device), ACPI_SMBUS_HC_DEVICE_NAME);
 370         strcpy(acpi_device_class(device), ACPI_SMBUS_HC_CLASS);
 371         device->driver_data = smbus_cmi;
 372         smbus_cmi->cap_info = 0;
 373         smbus_cmi->cap_read = 0;
 374         smbus_cmi->cap_write = 0;
 375
 376         for (id = acpi_smbus_cmi_ids; id->id[0]; id++)
 377                 if (!strcmp(id->id, acpi_device_hid(device)))
 378                         smbus_cmi->methods =
 379                                 (struct smbus_methods_t *) id->driver_data;
 380
 381         acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
 382                             acpi_smbus_cmi_query_methods, NULL, smbus_cmi, NULL);
 383
 384         if (smbus_cmi->cap_info == 0)
 385                 goto err;
 386
 387         snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
 388                 "SMBus CMI adapter %s",
 389                 acpi_device_name(device));
 390         smbus_cmi->adapter.owner = THIS_MODULE;
 391         smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
 392         smbus_cmi->adapter.algo_data = smbus_cmi;
 393         smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 394         smbus_cmi->adapter.dev.parent = &device->dev;
 395
 396         if (i2c_add_adapter(&smbus_cmi->adapter)) {
 397                 dev_err(&device->dev, "Couldn't register adapter!\n");
 398                 goto err;
 399         }
 400
 401         return 0;
 402
 403 err:
 404         kfree(smbus_cmi);
 405         device->driver_data = NULL;
 406         return -EIO;
 407 }
 408
 409 static int acpi_smbus_cmi_remove(struct acpi_device *device, int type)
 410 {
 411         struct acpi_smbus_cmi *smbus_cmi = acpi_driver_data(device);
 412
 413         i2c_del_adapter(&smbus_cmi->adapter);
 414         kfree(smbus_cmi);
 415         device->driver_data = NULL;
 416
 417         return 0;
 418 }
 419
 420 static struct acpi_driver acpi_smbus_cmi_driver = {
 421         .name = ACPI_SMBUS_HC_DEVICE_NAME,
 422         .class = ACPI_SMBUS_HC_CLASS,
 423         .ids = acpi_smbus_cmi_ids,
 424         .ops = {
 425                 .add = acpi_smbus_cmi_add,
 426                 .remove = acpi_smbus_cmi_remove,
 427         },
 428 };
 429
 430 static int __init acpi_smbus_cmi_init(void)
 431 {
 432         return acpi_bus_register_driver(&acpi_smbus_cmi_driver);
 433 }
 434
 435 static void __exit acpi_smbus_cmi_exit(void)
 436 {
 437         acpi_bus_unregister_driver(&acpi_smbus_cmi_driver);
 438 }
 439
 440 module_init(acpi_smbus_cmi_init);
 441 module_exit(acpi_smbus_cmi_exit);
 442
 443 MODULE_LICENSE("GPL");
 444 MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
 445 MODULE_DESCRIPTION("ACPI SMBus CMI driver");