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/i2c.h>
  16 #include <linux/acpi.h>
  17
  18 #define ACPI_SMBUS_HC_CLASS             "smbus"
  19 #define ACPI_SMBUS_HC_DEVICE_NAME       "cmi"
  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         {"", 0}
  55 };
  56 MODULE_DEVICE_TABLE(acpi, acpi_smbus_cmi_ids);
  57
  58 #define ACPI_SMBUS_STATUS_OK                    0x00
  59 #define ACPI_SMBUS_STATUS_FAIL                  0x07
  60 #define ACPI_SMBUS_STATUS_DNAK                  0x10
  61 #define ACPI_SMBUS_STATUS_DERR                  0x11
  62 #define ACPI_SMBUS_STATUS_CMD_DENY              0x12
  63 #define ACPI_SMBUS_STATUS_UNKNOWN               0x13
  64 #define ACPI_SMBUS_STATUS_ACC_DENY              0x17
  65 #define ACPI_SMBUS_STATUS_TIMEOUT               0x18
  66 #define ACPI_SMBUS_STATUS_NOTSUP                0x19
  67 #define ACPI_SMBUS_STATUS_BUSY                  0x1a
  68 #define ACPI_SMBUS_STATUS_PEC                   0x1f
  69
  70 #define ACPI_SMBUS_PRTCL_WRITE                  0x00
  71 #define ACPI_SMBUS_PRTCL_READ                   0x01
  72 #define ACPI_SMBUS_PRTCL_QUICK                  0x02
  73 #define ACPI_SMBUS_PRTCL_BYTE                   0x04
  74 #define ACPI_SMBUS_PRTCL_BYTE_DATA              0x06
  75 #define ACPI_SMBUS_PRTCL_WORD_DATA              0x08
  76 #define ACPI_SMBUS_PRTCL_BLOCK_DATA             0x0a
  77
  78
  79 static int
  80 acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
  81                    char read_write, u8 command, int size,
  82                    union i2c_smbus_data *data)
  83 {
  84         int result = 0;
  85         struct acpi_smbus_cmi *smbus_cmi = adap->algo_data;
  86         unsigned char protocol;
  87         acpi_status status = 0;
  88         struct acpi_object_list input;
  89         union acpi_object mt_params[5];
  90         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  91         union acpi_object *obj;
  92         union acpi_object *pkg;
  93         char *method;
  94         int len = 0;
  95
  96         dev_dbg(&adap->dev, "access size: %d %s\n", size,
  97                 (read_write) ? "READ" : "WRITE");
  98         switch (size) {
  99         case I2C_SMBUS_QUICK:
 100                 protocol = ACPI_SMBUS_PRTCL_QUICK;
 101                 command = 0;
 102                 if (read_write == I2C_SMBUS_WRITE) {
 103                         mt_params[3].type = ACPI_TYPE_INTEGER;
 104                         mt_params[3].integer.value = 0;
 105                         mt_params[4].type = ACPI_TYPE_INTEGER;
 106                         mt_params[4].integer.value = 0;
 107                 }
 108                 break;
 109
 110         case I2C_SMBUS_BYTE:
 111                 protocol = ACPI_SMBUS_PRTCL_BYTE;
 112                 if (read_write == I2C_SMBUS_WRITE) {
 113                         mt_params[3].type = ACPI_TYPE_INTEGER;
 114                         mt_params[3].integer.value = 0;
 115                         mt_params[4].type = ACPI_TYPE_INTEGER;
 116                         mt_params[4].integer.value = 0;
 117                 } else {
 118                         command = 0;
 119                 }
 120                 break;
 121
 122         case I2C_SMBUS_BYTE_DATA:
 123                 protocol = ACPI_SMBUS_PRTCL_BYTE_DATA;
 124                 if (read_write == I2C_SMBUS_WRITE) {
 125                         mt_params[3].type = ACPI_TYPE_INTEGER;
 126                         mt_params[3].integer.value = 1;
 127                         mt_params[4].type = ACPI_TYPE_INTEGER;
 128                         mt_params[4].integer.value = data->byte;
 129                 }
 130                 break;
 131
 132         case I2C_SMBUS_WORD_DATA:
 133                 protocol = ACPI_SMBUS_PRTCL_WORD_DATA;
 134                 if (read_write == I2C_SMBUS_WRITE) {
 135                         mt_params[3].type = ACPI_TYPE_INTEGER;
 136                         mt_params[3].integer.value = 2;
 137                         mt_params[4].type = ACPI_TYPE_INTEGER;
 138                         mt_params[4].integer.value = data->word;
 139                 }
 140                 break;
 141
 142         case I2C_SMBUS_BLOCK_DATA:
 143                 protocol = ACPI_SMBUS_PRTCL_BLOCK_DATA;
 144                 if (read_write == I2C_SMBUS_WRITE) {
 145                         len = data->block[0];
 146                         if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 147                                 return -EINVAL;
 148                         mt_params[3].type = ACPI_TYPE_INTEGER;
 149                         mt_params[3].integer.value = len;
 150                         mt_params[4].type = ACPI_TYPE_BUFFER;
 151                         mt_params[4].buffer.pointer = data->block + 1;
 152                 }
 153                 break;
 154
 155         default:
 156                 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 157                 return -EOPNOTSUPP;
 158         }
 159
 160         if (read_write == I2C_SMBUS_READ) {
 161                 protocol |= ACPI_SMBUS_PRTCL_READ;
 162                 method = smbus_cmi->methods->mt_sbr;
 163                 input.count = 3;
 164         } else {
 165                 protocol |= ACPI_SMBUS_PRTCL_WRITE;
 166                 method = smbus_cmi->methods->mt_sbw;
 167                 input.count = 5;
 168         }
 169
 170         input.pointer = mt_params;
 171         mt_params[0].type = ACPI_TYPE_INTEGER;
 172         mt_params[0].integer.value = protocol;
 173         mt_params[1].type = ACPI_TYPE_INTEGER;
 174         mt_params[1].integer.value = addr;
 175         mt_params[2].type = ACPI_TYPE_INTEGER;
 176         mt_params[2].integer.value = command;
 177
 178         status = acpi_evaluate_object(smbus_cmi->handle, method, &input,
 179                                       &buffer);
 180         if (ACPI_FAILURE(status)) {
 181                 ACPI_ERROR((AE_INFO, "Evaluating %s: %i", method, status));
 182                 return -EIO;
 183         }
 184
 185         pkg = buffer.pointer;
 186         if (pkg && pkg->type == ACPI_TYPE_PACKAGE)
 187                 obj = pkg->package.elements;
 188         else {
 189                 ACPI_ERROR((AE_INFO, "Invalid argument type"));
 190                 result = -EIO;
 191                 goto out;
 192         }
 193         if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 194                 ACPI_ERROR((AE_INFO, "Invalid argument type"));
 195                 result = -EIO;
 196                 goto out;
 197         }
 198
 199         result = obj->integer.value;
 200         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s return status: %i\n",
 201                           method, result));
 202
 203         switch (result) {
 204         case ACPI_SMBUS_STATUS_OK:
 205                 result = 0;
 206                 break;
 207         case ACPI_SMBUS_STATUS_BUSY:
 208                 result = -EBUSY;
 209                 goto out;
 210         case ACPI_SMBUS_STATUS_TIMEOUT:
 211                 result = -ETIMEDOUT;
 212                 goto out;
 213         case ACPI_SMBUS_STATUS_DNAK:
 214                 result = -ENXIO;
 215                 goto out;
 216         default:
 217                 result = -EIO;
 218                 goto out;
 219         }
 220
 221         if (read_write == I2C_SMBUS_WRITE || size == I2C_SMBUS_QUICK)
 222                 goto out;
 223
 224         obj = pkg->package.elements + 1;
 225         if (obj->type != ACPI_TYPE_INTEGER) {
 226                 ACPI_ERROR((AE_INFO, "Invalid argument type"));
 227                 result = -EIO;
 228                 goto out;
 229         }
 230
 231         len = obj->integer.value;
 232         obj = pkg->package.elements + 2;
 233         switch (size) {
 234         case I2C_SMBUS_BYTE:
 235         case I2C_SMBUS_BYTE_DATA:
 236         case I2C_SMBUS_WORD_DATA:
 237                 if (obj->type != ACPI_TYPE_INTEGER) {
 238                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 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_ERROR((AE_INFO, "Invalid argument type"));
 250                         result = -EIO;
 251                         goto out;
 252                 }
 253                 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 254                         return -EPROTO;
 255                 data->block[0] = len;
 256                 memcpy(data->block + 1, obj->buffer.pointer, len);
 257                 break;
 258         }
 259
 260 out:
 261         kfree(buffer.pointer);
 262         dev_dbg(&adap->dev, "Transaction status: %i\n", result);
 263         return result;
 264 }
 265
 266 static u32 acpi_smbus_cmi_func(struct i2c_adapter *adapter)
 267 {
 268         struct acpi_smbus_cmi *smbus_cmi = adapter->algo_data;
 269         u32 ret;
 270
 271         ret = smbus_cmi->cap_read | smbus_cmi->cap_write ?
 272                 I2C_FUNC_SMBUS_QUICK : 0;
 273
 274         ret |= smbus_cmi->cap_read ?
 275                 (I2C_FUNC_SMBUS_READ_BYTE |
 276                 I2C_FUNC_SMBUS_READ_BYTE_DATA |
 277                 I2C_FUNC_SMBUS_READ_WORD_DATA |
 278                 I2C_FUNC_SMBUS_READ_BLOCK_DATA) : 0;
 279
 280         ret |= smbus_cmi->cap_write ?
 281                 (I2C_FUNC_SMBUS_WRITE_BYTE |
 282                 I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
 283                 I2C_FUNC_SMBUS_WRITE_WORD_DATA |
 284                 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) : 0;
 285
 286         return ret;
 287 }
 288
 289 static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
 290         .smbus_xfer = acpi_smbus_cmi_access,
 291         .functionality = acpi_smbus_cmi_func,
 292 };
 293
 294
 295 static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
 296                                   const char *name)
 297 {
 298         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 299         union acpi_object *obj;
 300         acpi_status status;
 301
 302         if (!strcmp(name, smbus_cmi->methods->mt_info)) {
 303                 status = acpi_evaluate_object(smbus_cmi->handle,
 304                                         smbus_cmi->methods->mt_info,
 305                                         NULL, &buffer);
 306                 if (ACPI_FAILURE(status)) {
 307                         ACPI_ERROR((AE_INFO, "Evaluating %s: %i",
 308                                    smbus_cmi->methods->mt_info, status));
 309                         return -EIO;
 310                 }
 311
 312                 obj = buffer.pointer;
 313                 if (obj && obj->type == ACPI_TYPE_PACKAGE)
 314                         obj = obj->package.elements;
 315                 else {
 316                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 317                         kfree(buffer.pointer);
 318                         return -EIO;
 319                 }
 320
 321                 if (obj->type != ACPI_TYPE_INTEGER) {
 322                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 323                         kfree(buffer.pointer);
 324                         return -EIO;
 325                 } else
 326                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "SMBus CMI Version %x"
 327                                           "\n", (int)obj->integer.value));
 328
 329                 kfree(buffer.pointer);
 330                 smbus_cmi->cap_info = 1;
 331         } else if (!strcmp(name, smbus_cmi->methods->mt_sbr))
 332                 smbus_cmi->cap_read = 1;
 333         else if (!strcmp(name, smbus_cmi->methods->mt_sbw))
 334                 smbus_cmi->cap_write = 1;
 335         else
 336                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Unsupported CMI method: %s\n",
 337                                  name));
 338
 339         return 0;
 340 }
 341
 342 static acpi_status acpi_smbus_cmi_query_methods(acpi_handle handle, u32 level,
 343                         void *context, void **return_value)
 344 {
 345         char node_name[5];
 346         struct acpi_buffer buffer = { sizeof(node_name), node_name };
 347         struct acpi_smbus_cmi *smbus_cmi = context;
 348         acpi_status status;
 349
 350         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 351
 352         if (ACPI_SUCCESS(status))
 353                 acpi_smbus_cmi_add_cap(smbus_cmi, node_name);
 354
 355         return AE_OK;
 356 }
 357
 358 static int acpi_smbus_cmi_add(struct acpi_device *device)
 359 {
 360         struct acpi_smbus_cmi *smbus_cmi;
 361         const struct acpi_device_id *id;
 362
 363         smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
 364         if (!smbus_cmi)
 365                 return -ENOMEM;
 366
 367         smbus_cmi->handle = device->handle;
 368         strcpy(acpi_device_name(device), ACPI_SMBUS_HC_DEVICE_NAME);
 369         strcpy(acpi_device_class(device), ACPI_SMBUS_HC_CLASS);
 370         device->driver_data = smbus_cmi;
 371         smbus_cmi->cap_info = 0;
 372         smbus_cmi->cap_read = 0;
 373         smbus_cmi->cap_write = 0;
 374
 375         for (id = acpi_smbus_cmi_ids; id->id[0]; id++)
 376                 if (!strcmp(id->id, acpi_device_hid(device)))
 377                         smbus_cmi->methods =
 378                                 (struct smbus_methods_t *) id->driver_data;
 379
 380         acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
 381                             acpi_smbus_cmi_query_methods, NULL, smbus_cmi, NULL);
 382
 383         if (smbus_cmi->cap_info == 0)
 384                 goto err;
 385
 386         snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
 387                 "SMBus CMI adapter %s",
 388                 acpi_device_name(device));
 389         smbus_cmi->adapter.owner = THIS_MODULE;
 390         smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
 391         smbus_cmi->adapter.algo_data = smbus_cmi;
 392         smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 393         smbus_cmi->adapter.dev.parent = &device->dev;
 394
 395         if (i2c_add_adapter(&smbus_cmi->adapter)) {
 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         device->driver_data = NULL;
 405         return -EIO;
 406 }
 407
 408 static int acpi_smbus_cmi_remove(struct acpi_device *device)
 409 {
 410         struct acpi_smbus_cmi *smbus_cmi = acpi_driver_data(device);
 411
 412         i2c_del_adapter(&smbus_cmi->adapter);
 413         kfree(smbus_cmi);
 414         device->driver_data = NULL;
 415
 416         return 0;
 417 }
 418
 419 static struct acpi_driver acpi_smbus_cmi_driver = {
 420         .name = ACPI_SMBUS_HC_DEVICE_NAME,
 421         .class = ACPI_SMBUS_HC_CLASS,
 422         .ids = acpi_smbus_cmi_ids,
 423         .ops = {
 424                 .add = acpi_smbus_cmi_add,
 425                 .remove = acpi_smbus_cmi_remove,
 426         },
 427 };
 428 module_acpi_driver(acpi_smbus_cmi_driver);
 429
 430 MODULE_LICENSE("GPL");
 431 MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
 432 MODULE_DESCRIPTION("ACPI SMBus CMI driver");