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 /* SMBUS HID definition as supported by Microsoft Windows */
  22 #define ACPI_SMBUS_MS_HID               "SMB0001"
  23
  24 ACPI_MODULE_NAME("smbus_cmi");
  25
  26 struct smbus_methods_t {
  27         char *mt_info;
  28         char *mt_sbr;
  29         char *mt_sbw;
  30 };
  31
  32 struct acpi_smbus_cmi {
  33         acpi_handle handle;
  34         struct i2c_adapter adapter;
  35         u8 cap_info:1;
  36         u8 cap_read:1;
  37         u8 cap_write:1;
  38         struct smbus_methods_t *methods;
  39 };
  40
  41 static const struct smbus_methods_t smbus_methods = {
  42         .mt_info = "_SBI",
  43         .mt_sbr  = "_SBR",
  44         .mt_sbw  = "_SBW",
  45 };
  46
  47 /* Some IBM BIOSes omit the leading underscore */
  48 static const struct smbus_methods_t ibm_smbus_methods = {
  49         .mt_info = "SBI_",
  50         .mt_sbr  = "SBR_",
  51         .mt_sbw  = "SBW_",
  52 };
  53
  54 static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
  55         {"SMBUS01", (kernel_ulong_t)&smbus_methods},
  56         {ACPI_SMBUS_IBM_HID, (kernel_ulong_t)&ibm_smbus_methods},
  57         {ACPI_SMBUS_MS_HID, (kernel_ulong_t)&smbus_methods},
  58         {"", 0}
  59 };
  60 MODULE_DEVICE_TABLE(acpi, acpi_smbus_cmi_ids);
  61
  62 #define ACPI_SMBUS_STATUS_OK                    0x00
  63 #define ACPI_SMBUS_STATUS_FAIL                  0x07
  64 #define ACPI_SMBUS_STATUS_DNAK                  0x10
  65 #define ACPI_SMBUS_STATUS_DERR                  0x11
  66 #define ACPI_SMBUS_STATUS_CMD_DENY              0x12
  67 #define ACPI_SMBUS_STATUS_UNKNOWN               0x13
  68 #define ACPI_SMBUS_STATUS_ACC_DENY              0x17
  69 #define ACPI_SMBUS_STATUS_TIMEOUT               0x18
  70 #define ACPI_SMBUS_STATUS_NOTSUP                0x19
  71 #define ACPI_SMBUS_STATUS_BUSY                  0x1a
  72 #define ACPI_SMBUS_STATUS_PEC                   0x1f
  73
  74 #define ACPI_SMBUS_PRTCL_WRITE                  0x00
  75 #define ACPI_SMBUS_PRTCL_READ                   0x01
  76 #define ACPI_SMBUS_PRTCL_QUICK                  0x02
  77 #define ACPI_SMBUS_PRTCL_BYTE                   0x04
  78 #define ACPI_SMBUS_PRTCL_BYTE_DATA              0x06
  79 #define ACPI_SMBUS_PRTCL_WORD_DATA              0x08
  80 #define ACPI_SMBUS_PRTCL_BLOCK_DATA             0x0a
  81
  82
  83 static int
  84 acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
  85                    char read_write, u8 command, int size,
  86                    union i2c_smbus_data *data)
  87 {
  88         int result = 0;
  89         struct acpi_smbus_cmi *smbus_cmi = adap->algo_data;
  90         unsigned char protocol;
  91         acpi_status status = 0;
  92         struct acpi_object_list input;
  93         union acpi_object mt_params[5];
  94         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  95         union acpi_object *obj;
  96         union acpi_object *pkg;
  97         char *method;
  98         int len = 0;
  99
 100         dev_dbg(&adap->dev, "access size: %d %s\n", size,
 101                 (read_write) ? "READ" : "WRITE");
 102         switch (size) {
 103         case I2C_SMBUS_QUICK:
 104                 protocol = ACPI_SMBUS_PRTCL_QUICK;
 105                 command = 0;
 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                 }
 112                 break;
 113
 114         case I2C_SMBUS_BYTE:
 115                 protocol = ACPI_SMBUS_PRTCL_BYTE;
 116                 if (read_write == I2C_SMBUS_WRITE) {
 117                         mt_params[3].type = ACPI_TYPE_INTEGER;
 118                         mt_params[3].integer.value = 0;
 119                         mt_params[4].type = ACPI_TYPE_INTEGER;
 120                         mt_params[4].integer.value = 0;
 121                 } else {
 122                         command = 0;
 123                 }
 124                 break;
 125
 126         case I2C_SMBUS_BYTE_DATA:
 127                 protocol = ACPI_SMBUS_PRTCL_BYTE_DATA;
 128                 if (read_write == I2C_SMBUS_WRITE) {
 129                         mt_params[3].type = ACPI_TYPE_INTEGER;
 130                         mt_params[3].integer.value = 1;
 131                         mt_params[4].type = ACPI_TYPE_INTEGER;
 132                         mt_params[4].integer.value = data->byte;
 133                 }
 134                 break;
 135
 136         case I2C_SMBUS_WORD_DATA:
 137                 protocol = ACPI_SMBUS_PRTCL_WORD_DATA;
 138                 if (read_write == I2C_SMBUS_WRITE) {
 139                         mt_params[3].type = ACPI_TYPE_INTEGER;
 140                         mt_params[3].integer.value = 2;
 141                         mt_params[4].type = ACPI_TYPE_INTEGER;
 142                         mt_params[4].integer.value = data->word;
 143                 }
 144                 break;
 145
 146         case I2C_SMBUS_BLOCK_DATA:
 147                 protocol = ACPI_SMBUS_PRTCL_BLOCK_DATA;
 148                 if (read_write == I2C_SMBUS_WRITE) {
 149                         len = data->block[0];
 150                         if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 151                                 return -EINVAL;
 152                         mt_params[3].type = ACPI_TYPE_INTEGER;
 153                         mt_params[3].integer.value = len;
 154                         mt_params[4].type = ACPI_TYPE_BUFFER;
 155                         mt_params[4].buffer.length = len;
 156                         mt_params[4].buffer.pointer = data->block + 1;
 157                 }
 158                 break;
 159
 160         default:
 161                 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 162                 return -EOPNOTSUPP;
 163         }
 164
 165         if (read_write == I2C_SMBUS_READ) {
 166                 protocol |= ACPI_SMBUS_PRTCL_READ;
 167                 method = smbus_cmi->methods->mt_sbr;
 168                 input.count = 3;
 169         } else {
 170                 protocol |= ACPI_SMBUS_PRTCL_WRITE;
 171                 method = smbus_cmi->methods->mt_sbw;
 172                 input.count = 5;
 173         }
 174
 175         input.pointer = mt_params;
 176         mt_params[0].type = ACPI_TYPE_INTEGER;
 177         mt_params[0].integer.value = protocol;
 178         mt_params[1].type = ACPI_TYPE_INTEGER;
 179         mt_params[1].integer.value = addr;
 180         mt_params[2].type = ACPI_TYPE_INTEGER;
 181         mt_params[2].integer.value = command;
 182
 183         status = acpi_evaluate_object(smbus_cmi->handle, method, &input,
 184                                       &buffer);
 185         if (ACPI_FAILURE(status)) {
 186                 acpi_handle_err(smbus_cmi->handle,
 187                                 "Failed to evaluate %s: %i\n", method, status);
 188                 return -EIO;
 189         }
 190
 191         pkg = buffer.pointer;
 192         if (pkg && pkg->type == ACPI_TYPE_PACKAGE)
 193                 obj = pkg->package.elements;
 194         else {
 195                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 196                 result = -EIO;
 197                 goto out;
 198         }
 199         if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 200                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 201                 result = -EIO;
 202                 goto out;
 203         }
 204
 205         result = obj->integer.value;
 206         acpi_handle_debug(smbus_cmi->handle,  "%s return status: %i\n", method,
 207                           result);
 208
 209         switch (result) {
 210         case ACPI_SMBUS_STATUS_OK:
 211                 result = 0;
 212                 break;
 213         case ACPI_SMBUS_STATUS_BUSY:
 214                 result = -EBUSY;
 215                 goto out;
 216         case ACPI_SMBUS_STATUS_TIMEOUT:
 217                 result = -ETIMEDOUT;
 218                 goto out;
 219         case ACPI_SMBUS_STATUS_DNAK:
 220                 result = -ENXIO;
 221                 goto out;
 222         default:
 223                 result = -EIO;
 224                 goto out;
 225         }
 226
 227         if (read_write == I2C_SMBUS_WRITE || size == I2C_SMBUS_QUICK)
 228                 goto out;
 229
 230         obj = pkg->package.elements + 1;
 231         if (obj->type != ACPI_TYPE_INTEGER) {
 232                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 233                 result = -EIO;
 234                 goto out;
 235         }
 236
 237         len = obj->integer.value;
 238         obj = pkg->package.elements + 2;
 239         switch (size) {
 240         case I2C_SMBUS_BYTE:
 241         case I2C_SMBUS_BYTE_DATA:
 242         case I2C_SMBUS_WORD_DATA:
 243                 if (obj->type != ACPI_TYPE_INTEGER) {
 244                         acpi_handle_err(smbus_cmi->handle,
 245                                         "Invalid argument type\n");
 246                         result = -EIO;
 247                         goto out;
 248                 }
 249                 if (len == 2)
 250                         data->word = obj->integer.value;
 251                 else
 252                         data->byte = obj->integer.value;
 253                 break;
 254         case I2C_SMBUS_BLOCK_DATA:
 255                 if (obj->type != ACPI_TYPE_BUFFER) {
 256                         acpi_handle_err(smbus_cmi->handle,
 257                                         "Invalid argument type\n");
 258                         result = -EIO;
 259                         goto out;
 260                 }
 261                 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 262                         return -EPROTO;
 263                 data->block[0] = len;
 264                 memcpy(data->block + 1, obj->buffer.pointer, len);
 265                 break;
 266         }
 267
 268 out:
 269         kfree(buffer.pointer);
 270         dev_dbg(&adap->dev, "Transaction status: %i\n", result);
 271         return result;
 272 }
 273
 274 static u32 acpi_smbus_cmi_func(struct i2c_adapter *adapter)
 275 {
 276         struct acpi_smbus_cmi *smbus_cmi = adapter->algo_data;
 277         u32 ret;
 278
 279         ret = smbus_cmi->cap_read | smbus_cmi->cap_write ?
 280                 I2C_FUNC_SMBUS_QUICK : 0;
 281
 282         ret |= smbus_cmi->cap_read ?
 283                 (I2C_FUNC_SMBUS_READ_BYTE |
 284                 I2C_FUNC_SMBUS_READ_BYTE_DATA |
 285                 I2C_FUNC_SMBUS_READ_WORD_DATA |
 286                 I2C_FUNC_SMBUS_READ_BLOCK_DATA) : 0;
 287
 288         ret |= smbus_cmi->cap_write ?
 289                 (I2C_FUNC_SMBUS_WRITE_BYTE |
 290                 I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
 291                 I2C_FUNC_SMBUS_WRITE_WORD_DATA |
 292                 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) : 0;
 293
 294         return ret;
 295 }
 296
 297 static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
 298         .smbus_xfer = acpi_smbus_cmi_access,
 299         .functionality = acpi_smbus_cmi_func,
 300 };
 301
 302
 303 static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
 304                                   const char *name)
 305 {
 306         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 307         struct acpi_handle *handle = smbus_cmi->handle;
 308         union acpi_object *obj;
 309         acpi_status status;
 310
 311         if (!strcmp(name, smbus_cmi->methods->mt_info)) {
 312                 status = acpi_evaluate_object(smbus_cmi->handle,
 313                                         smbus_cmi->methods->mt_info,
 314                                         NULL, &buffer);
 315                 if (ACPI_FAILURE(status)) {
 316                         acpi_handle_err(handle, "Failed to evaluate %s: %i\n",
 317                                         smbus_cmi->methods->mt_info, status);
 318                         return -EIO;
 319                 }
 320
 321                 obj = buffer.pointer;
 322                 if (obj && obj->type == ACPI_TYPE_PACKAGE)
 323                         obj = obj->package.elements;
 324                 else {
 325                         acpi_handle_err(handle, "Invalid argument type\n");
 326                         kfree(buffer.pointer);
 327                         return -EIO;
 328                 }
 329
 330                 if (obj->type != ACPI_TYPE_INTEGER) {
 331                         acpi_handle_err(handle, "Invalid argument type\n");
 332                         kfree(buffer.pointer);
 333                         return -EIO;
 334                 } else
 335                         acpi_handle_debug(handle, "SMBus CMI Version %x\n",
 336                                           (int)obj->integer.value);
 337
 338                 kfree(buffer.pointer);
 339                 smbus_cmi->cap_info = 1;
 340         } else if (!strcmp(name, smbus_cmi->methods->mt_sbr))
 341                 smbus_cmi->cap_read = 1;
 342         else if (!strcmp(name, smbus_cmi->methods->mt_sbw))
 343                 smbus_cmi->cap_write = 1;
 344         else
 345                 acpi_handle_debug(handle, "Unsupported CMI method: %s\n", name);
 346
 347         return 0;
 348 }
 349
 350 static acpi_status acpi_smbus_cmi_query_methods(acpi_handle handle, u32 level,
 351                         void *context, void **return_value)
 352 {
 353         char node_name[5];
 354         struct acpi_buffer buffer = { sizeof(node_name), node_name };
 355         struct acpi_smbus_cmi *smbus_cmi = context;
 356         acpi_status status;
 357
 358         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 359
 360         if (ACPI_SUCCESS(status))
 361                 acpi_smbus_cmi_add_cap(smbus_cmi, node_name);
 362
 363         return AE_OK;
 364 }
 365
 366 static int acpi_smbus_cmi_add(struct acpi_device *device)
 367 {
 368         struct acpi_smbus_cmi *smbus_cmi;
 369         const struct acpi_device_id *id;
 370         int ret;
 371
 372         smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
 373         if (!smbus_cmi)
 374                 return -ENOMEM;
 375
 376         smbus_cmi->handle = device->handle;
 377         strcpy(acpi_device_name(device), ACPI_SMBUS_HC_DEVICE_NAME);
 378         strcpy(acpi_device_class(device), ACPI_SMBUS_HC_CLASS);
 379         device->driver_data = smbus_cmi;
 380         smbus_cmi->cap_info = 0;
 381         smbus_cmi->cap_read = 0;
 382         smbus_cmi->cap_write = 0;
 383
 384         for (id = acpi_smbus_cmi_ids; id->id[0]; id++)
 385                 if (!strcmp(id->id, acpi_device_hid(device)))
 386                         smbus_cmi->methods =
 387                                 (struct smbus_methods_t *) id->driver_data;
 388
 389         acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
 390                             acpi_smbus_cmi_query_methods, NULL, smbus_cmi, NULL);
 391
 392         if (smbus_cmi->cap_info == 0) {
 393                 ret = -ENODEV;
 394                 goto err;
 395         }
 396
 397         snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
 398                 "SMBus CMI adapter %s",
 399                 acpi_device_name(device));
 400         smbus_cmi->adapter.owner = THIS_MODULE;
 401         smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
 402         smbus_cmi->adapter.algo_data = smbus_cmi;
 403         smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 404         smbus_cmi->adapter.dev.parent = &device->dev;
 405
 406         ret = i2c_add_adapter(&smbus_cmi->adapter);
 407         if (ret) {
 408                 dev_err(&device->dev, "Couldn't register adapter!\n");
 409                 goto err;
 410         }
 411
 412         return 0;
 413
 414 err:
 415         kfree(smbus_cmi);
 416         device->driver_data = NULL;
 417         return ret;
 418 }
 419
 420 static int acpi_smbus_cmi_remove(struct acpi_device *device)
 421 {
 422         struct acpi_smbus_cmi *smbus_cmi = acpi_driver_data(device);
 423
 424         i2c_del_adapter(&smbus_cmi->adapter);
 425         kfree(smbus_cmi);
 426         device->driver_data = NULL;
 427
 428         return 0;
 429 }
 430
 431 static struct acpi_driver acpi_smbus_cmi_driver = {
 432         .name = ACPI_SMBUS_HC_DEVICE_NAME,
 433         .class = ACPI_SMBUS_HC_CLASS,
 434         .ids = acpi_smbus_cmi_ids,
 435         .ops = {
 436                 .add = acpi_smbus_cmi_add,
 437                 .remove = acpi_smbus_cmi_remove,
 438         },
 439 };
 440 module_acpi_driver(acpi_smbus_cmi_driver);
 441
 442 MODULE_LICENSE("GPL");
 443 MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
 444 MODULE_DESCRIPTION("ACPI SMBus CMI driver");