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 struct smbus_methods_t {
  22         char *mt_info;
  23         char *mt_sbr;
  24         char *mt_sbw;
  25 };
  26
  27 struct acpi_smbus_cmi {
  28         acpi_handle handle;
  29         struct i2c_adapter adapter;
  30         u8 cap_info:1;
  31         u8 cap_read:1;
  32         u8 cap_write:1;
  33         struct smbus_methods_t *methods;
  34 };
  35
  36 static const struct smbus_methods_t smbus_methods = {
  37         .mt_info = "_SBI",
  38         .mt_sbr  = "_SBR",
  39         .mt_sbw  = "_SBW",
  40 };
  41
  42 /* Some IBM BIOSes omit the leading underscore */
  43 static const struct smbus_methods_t ibm_smbus_methods = {
  44         .mt_info = "SBI_",
  45         .mt_sbr  = "SBR_",
  46         .mt_sbw  = "SBW_",
  47 };
  48
  49 static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
  50         {"SMBUS01", (kernel_ulong_t)&smbus_methods},
  51         {ACPI_SMBUS_IBM_HID, (kernel_ulong_t)&ibm_smbus_methods},
  52         {ACPI_SMBUS_MS_HID, (kernel_ulong_t)&smbus_methods},
  53         {"", 0}
  54 };
  55 MODULE_DEVICE_TABLE(acpi, acpi_smbus_cmi_ids);
  56
  57 #define ACPI_SMBUS_STATUS_OK                    0x00
  58 #define ACPI_SMBUS_STATUS_FAIL                  0x07
  59 #define ACPI_SMBUS_STATUS_DNAK                  0x10
  60 #define ACPI_SMBUS_STATUS_DERR                  0x11
  61 #define ACPI_SMBUS_STATUS_CMD_DENY              0x12
  62 #define ACPI_SMBUS_STATUS_UNKNOWN               0x13
  63 #define ACPI_SMBUS_STATUS_ACC_DENY              0x17
  64 #define ACPI_SMBUS_STATUS_TIMEOUT               0x18
  65 #define ACPI_SMBUS_STATUS_NOTSUP                0x19
  66 #define ACPI_SMBUS_STATUS_BUSY                  0x1a
  67 #define ACPI_SMBUS_STATUS_PEC                   0x1f
  68
  69 #define ACPI_SMBUS_PRTCL_WRITE                  0x00
  70 #define ACPI_SMBUS_PRTCL_READ                   0x01
  71 #define ACPI_SMBUS_PRTCL_QUICK                  0x02
  72 #define ACPI_SMBUS_PRTCL_BYTE                   0x04
  73 #define ACPI_SMBUS_PRTCL_BYTE_DATA              0x06
  74 #define ACPI_SMBUS_PRTCL_WORD_DATA              0x08
  75 #define ACPI_SMBUS_PRTCL_BLOCK_DATA             0x0a
  76
  77
  78 static int
  79 acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
  80                    char read_write, u8 command, int size,
  81                    union i2c_smbus_data *data)
  82 {
  83         int result = 0;
  84         struct acpi_smbus_cmi *smbus_cmi = adap->algo_data;
  85         unsigned char protocol;
  86         acpi_status status = 0;
  87         struct acpi_object_list input;
  88         union acpi_object mt_params[5];
  89         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  90         union acpi_object *obj;
  91         union acpi_object *pkg;
  92         char *method;
  93         int len = 0;
  94
  95         dev_dbg(&adap->dev, "access size: %d %s\n", size,
  96                 (read_write) ? "READ" : "WRITE");
  97         switch (size) {
  98         case I2C_SMBUS_QUICK:
  99                 protocol = ACPI_SMBUS_PRTCL_QUICK;
 100                 command = 0;
 101                 if (read_write == I2C_SMBUS_WRITE) {
 102                         mt_params[3].type = ACPI_TYPE_INTEGER;
 103                         mt_params[3].integer.value = 0;
 104                         mt_params[4].type = ACPI_TYPE_INTEGER;
 105                         mt_params[4].integer.value = 0;
 106                 }
 107                 break;
 108
 109         case I2C_SMBUS_BYTE:
 110                 protocol = ACPI_SMBUS_PRTCL_BYTE;
 111                 if (read_write == I2C_SMBUS_WRITE) {
 112                         mt_params[3].type = ACPI_TYPE_INTEGER;
 113                         mt_params[3].integer.value = 0;
 114                         mt_params[4].type = ACPI_TYPE_INTEGER;
 115                         mt_params[4].integer.value = 0;
 116                 } else {
 117                         command = 0;
 118                 }
 119                 break;
 120
 121         case I2C_SMBUS_BYTE_DATA:
 122                 protocol = ACPI_SMBUS_PRTCL_BYTE_DATA;
 123                 if (read_write == I2C_SMBUS_WRITE) {
 124                         mt_params[3].type = ACPI_TYPE_INTEGER;
 125                         mt_params[3].integer.value = 1;
 126                         mt_params[4].type = ACPI_TYPE_INTEGER;
 127                         mt_params[4].integer.value = data->byte;
 128                 }
 129                 break;
 130
 131         case I2C_SMBUS_WORD_DATA:
 132                 protocol = ACPI_SMBUS_PRTCL_WORD_DATA;
 133                 if (read_write == I2C_SMBUS_WRITE) {
 134                         mt_params[3].type = ACPI_TYPE_INTEGER;
 135                         mt_params[3].integer.value = 2;
 136                         mt_params[4].type = ACPI_TYPE_INTEGER;
 137                         mt_params[4].integer.value = data->word;
 138                 }
 139                 break;
 140
 141         case I2C_SMBUS_BLOCK_DATA:
 142                 protocol = ACPI_SMBUS_PRTCL_BLOCK_DATA;
 143                 if (read_write == I2C_SMBUS_WRITE) {
 144                         len = data->block[0];
 145                         if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 146                                 return -EINVAL;
 147                         mt_params[3].type = ACPI_TYPE_INTEGER;
 148                         mt_params[3].integer.value = len;
 149                         mt_params[4].type = ACPI_TYPE_BUFFER;
 150                         mt_params[4].buffer.length = len;
 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_handle_err(smbus_cmi->handle,
 182                                 "Failed to evaluate %s: %i\n", 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_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 191                 result = -EIO;
 192                 goto out;
 193         }
 194         if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 195                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 196                 result = -EIO;
 197                 goto out;
 198         }
 199
 200         result = obj->integer.value;
 201         acpi_handle_debug(smbus_cmi->handle,  "%s return status: %i\n", method,
 202                           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->type != ACPI_TYPE_INTEGER) {
 227                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 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->type != ACPI_TYPE_INTEGER) {
 239                         acpi_handle_err(smbus_cmi->handle,
 240                                         "Invalid argument type\n");
 241                         result = -EIO;
 242                         goto out;
 243                 }
 244                 if (len == 2)
 245                         data->word = obj->integer.value;
 246                 else
 247                         data->byte = obj->integer.value;
 248                 break;
 249         case I2C_SMBUS_BLOCK_DATA:
 250                 if (obj->type != ACPI_TYPE_BUFFER) {
 251                         acpi_handle_err(smbus_cmi->handle,
 252                                         "Invalid argument type\n");
 253                         result = -EIO;
 254                         goto out;
 255                 }
 256                 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 257                         return -EPROTO;
 258                 data->block[0] = len;
 259                 memcpy(data->block + 1, obj->buffer.pointer, len);
 260                 break;
 261         }
 262
 263 out:
 264         kfree(buffer.pointer);
 265         dev_dbg(&adap->dev, "Transaction status: %i\n", result);
 266         return result;
 267 }
 268
 269 static u32 acpi_smbus_cmi_func(struct i2c_adapter *adapter)
 270 {
 271         struct acpi_smbus_cmi *smbus_cmi = adapter->algo_data;
 272         u32 ret;
 273
 274         ret = smbus_cmi->cap_read | smbus_cmi->cap_write ?
 275                 I2C_FUNC_SMBUS_QUICK : 0;
 276
 277         ret |= smbus_cmi->cap_read ?
 278                 (I2C_FUNC_SMBUS_READ_BYTE |
 279                 I2C_FUNC_SMBUS_READ_BYTE_DATA |
 280                 I2C_FUNC_SMBUS_READ_WORD_DATA |
 281                 I2C_FUNC_SMBUS_READ_BLOCK_DATA) : 0;
 282
 283         ret |= smbus_cmi->cap_write ?
 284                 (I2C_FUNC_SMBUS_WRITE_BYTE |
 285                 I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
 286                 I2C_FUNC_SMBUS_WRITE_WORD_DATA |
 287                 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) : 0;
 288
 289         return ret;
 290 }
 291
 292 static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
 293         .smbus_xfer = acpi_smbus_cmi_access,
 294         .functionality = acpi_smbus_cmi_func,
 295 };
 296
 297
 298 static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
 299                                   const char *name)
 300 {
 301         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 302         struct acpi_handle *handle = smbus_cmi->handle;
 303         union acpi_object *obj;
 304         acpi_status status;
 305
 306         if (!strcmp(name, smbus_cmi->methods->mt_info)) {
 307                 status = acpi_evaluate_object(smbus_cmi->handle,
 308                                         smbus_cmi->methods->mt_info,
 309                                         NULL, &buffer);
 310                 if (ACPI_FAILURE(status)) {
 311                         acpi_handle_err(handle, "Failed to evaluate %s: %i\n",
 312                                         smbus_cmi->methods->mt_info, status);
 313                         return -EIO;
 314                 }
 315
 316                 obj = buffer.pointer;
 317                 if (obj && obj->type == ACPI_TYPE_PACKAGE)
 318                         obj = obj->package.elements;
 319                 else {
 320                         acpi_handle_err(handle, "Invalid argument type\n");
 321                         kfree(buffer.pointer);
 322                         return -EIO;
 323                 }
 324
 325                 if (obj->type != ACPI_TYPE_INTEGER) {
 326                         acpi_handle_err(handle, "Invalid argument type\n");
 327                         kfree(buffer.pointer);
 328                         return -EIO;
 329                 } else
 330                         acpi_handle_debug(handle, "SMBus CMI Version %x\n",
 331                                           (int)obj->integer.value);
 332
 333                 kfree(buffer.pointer);
 334                 smbus_cmi->cap_info = 1;
 335         } else if (!strcmp(name, smbus_cmi->methods->mt_sbr))
 336                 smbus_cmi->cap_read = 1;
 337         else if (!strcmp(name, smbus_cmi->methods->mt_sbw))
 338                 smbus_cmi->cap_write = 1;
 339         else
 340                 acpi_handle_debug(handle, "Unsupported CMI method: %s\n", name);
 341
 342         return 0;
 343 }
 344
 345 static acpi_status acpi_smbus_cmi_query_methods(acpi_handle handle, u32 level,
 346                         void *context, void **return_value)
 347 {
 348         char node_name[5];
 349         struct acpi_buffer buffer = { sizeof(node_name), node_name };
 350         struct acpi_smbus_cmi *smbus_cmi = context;
 351         acpi_status status;
 352
 353         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 354
 355         if (ACPI_SUCCESS(status))
 356                 acpi_smbus_cmi_add_cap(smbus_cmi, node_name);
 357
 358         return AE_OK;
 359 }
 360
 361 static int acpi_smbus_cmi_add(struct acpi_device *device)
 362 {
 363         struct acpi_smbus_cmi *smbus_cmi;
 364         const struct acpi_device_id *id;
 365         int ret;
 366
 367         smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
 368         if (!smbus_cmi)
 369                 return -ENOMEM;
 370
 371         smbus_cmi->handle = device->handle;
 372         strcpy(acpi_device_name(device), ACPI_SMBUS_HC_DEVICE_NAME);
 373         strcpy(acpi_device_class(device), ACPI_SMBUS_HC_CLASS);
 374         device->driver_data = smbus_cmi;
 375         smbus_cmi->cap_info = 0;
 376         smbus_cmi->cap_read = 0;
 377         smbus_cmi->cap_write = 0;
 378
 379         for (id = acpi_smbus_cmi_ids; id->id[0]; id++)
 380                 if (!strcmp(id->id, acpi_device_hid(device)))
 381                         smbus_cmi->methods =
 382                                 (struct smbus_methods_t *) id->driver_data;
 383
 384         acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
 385                             acpi_smbus_cmi_query_methods, NULL, smbus_cmi, NULL);
 386
 387         if (smbus_cmi->cap_info == 0) {
 388                 ret = -ENODEV;
 389                 goto err;
 390         }
 391
 392         snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
 393                 "SMBus CMI adapter %s",
 394                 acpi_device_name(device));
 395         smbus_cmi->adapter.owner = THIS_MODULE;
 396         smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
 397         smbus_cmi->adapter.algo_data = smbus_cmi;
 398         smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 399         smbus_cmi->adapter.dev.parent = &device->dev;
 400
 401         ret = i2c_add_adapter(&smbus_cmi->adapter);
 402         if (ret) {
 403                 dev_err(&device->dev, "Couldn't register adapter!\n");
 404                 goto err;
 405         }
 406
 407         return 0;
 408
 409 err:
 410         kfree(smbus_cmi);
 411         device->driver_data = NULL;
 412         return ret;
 413 }
 414
 415 static int acpi_smbus_cmi_remove(struct acpi_device *device)
 416 {
 417         struct acpi_smbus_cmi *smbus_cmi = acpi_driver_data(device);
 418
 419         i2c_del_adapter(&smbus_cmi->adapter);
 420         kfree(smbus_cmi);
 421         device->driver_data = NULL;
 422
 423         return 0;
 424 }
 425
 426 static struct acpi_driver acpi_smbus_cmi_driver = {
 427         .name = ACPI_SMBUS_HC_DEVICE_NAME,
 428         .class = ACPI_SMBUS_HC_CLASS,
 429         .ids = acpi_smbus_cmi_ids,
 430         .ops = {
 431                 .add = acpi_smbus_cmi_add,
 432                 .remove = acpi_smbus_cmi_remove,
 433         },
 434 };
 435 module_acpi_driver(acpi_smbus_cmi_driver);
 436
 437 MODULE_LICENSE("GPL");
 438 MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
 439 MODULE_DESCRIPTION("ACPI SMBus CMI driver");