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/platform_device.h>
  10 #include <linux/slab.h>
  11 #include <linux/kernel.h>
  12 #include <linux/stddef.h>
  13 #include <linux/i2c.h>
  14 #include <linux/acpi.h>
  15
  16 /* SMBUS HID definition as supported by Microsoft Windows */
  17 #define ACPI_SMBUS_MS_HID               "SMB0001"
  18
  19 struct smbus_methods_t {
  20         char *mt_info;
  21         char *mt_sbr;
  22         char *mt_sbw;
  23 };
  24
  25 struct acpi_smbus_cmi {
  26         acpi_handle handle;
  27         struct i2c_adapter adapter;
  28         u8 cap_info:1;
  29         u8 cap_read:1;
  30         u8 cap_write:1;
  31         const struct smbus_methods_t *methods;
  32 };
  33
  34 static const struct smbus_methods_t smbus_methods = {
  35         .mt_info = "_SBI",
  36         .mt_sbr  = "_SBR",
  37         .mt_sbw  = "_SBW",
  38 };
  39
  40 /* Some IBM BIOSes omit the leading underscore */
  41 static const struct smbus_methods_t ibm_smbus_methods = {
  42         .mt_info = "SBI_",
  43         .mt_sbr  = "SBR_",
  44         .mt_sbw  = "SBW_",
  45 };
  46
  47 static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
  48         {"SMBUS01", (kernel_ulong_t)&smbus_methods},
  49         {ACPI_SMBUS_IBM_HID, (kernel_ulong_t)&ibm_smbus_methods},
  50         {ACPI_SMBUS_MS_HID, (kernel_ulong_t)&smbus_methods},
  51         {"", 0}
  52 };
  53 MODULE_DEVICE_TABLE(acpi, acpi_smbus_cmi_ids);
  54
  55 #define ACPI_SMBUS_STATUS_OK                    0x00
  56 #define ACPI_SMBUS_STATUS_FAIL                  0x07
  57 #define ACPI_SMBUS_STATUS_DNAK                  0x10
  58 #define ACPI_SMBUS_STATUS_DERR                  0x11
  59 #define ACPI_SMBUS_STATUS_CMD_DENY              0x12
  60 #define ACPI_SMBUS_STATUS_UNKNOWN               0x13
  61 #define ACPI_SMBUS_STATUS_ACC_DENY              0x17
  62 #define ACPI_SMBUS_STATUS_TIMEOUT               0x18
  63 #define ACPI_SMBUS_STATUS_NOTSUP                0x19
  64 #define ACPI_SMBUS_STATUS_BUSY                  0x1a
  65 #define ACPI_SMBUS_STATUS_PEC                   0x1f
  66
  67 #define ACPI_SMBUS_PRTCL_WRITE                  0x00
  68 #define ACPI_SMBUS_PRTCL_READ                   0x01
  69 #define ACPI_SMBUS_PRTCL_QUICK                  0x02
  70 #define ACPI_SMBUS_PRTCL_BYTE                   0x04
  71 #define ACPI_SMBUS_PRTCL_BYTE_DATA              0x06
  72 #define ACPI_SMBUS_PRTCL_WORD_DATA              0x08
  73 #define ACPI_SMBUS_PRTCL_BLOCK_DATA             0x0a
  74
  75
  76 static int
  77 acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
  78                    char read_write, u8 command, int size,
  79                    union i2c_smbus_data *data)
  80 {
  81         int result = 0;
  82         struct acpi_smbus_cmi *smbus_cmi = adap->algo_data;
  83         unsigned char protocol;
  84         acpi_status status = 0;
  85         struct acpi_object_list input;
  86         union acpi_object mt_params[5];
  87         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  88         union acpi_object *obj;
  89         union acpi_object *pkg;
  90         char *method;
  91         int len = 0;
  92
  93         dev_dbg(&adap->dev, "access size: %d %s\n", size,
  94                 (read_write) ? "READ" : "WRITE");
  95         switch (size) {
  96         case I2C_SMBUS_QUICK:
  97                 protocol = ACPI_SMBUS_PRTCL_QUICK;
  98                 command = 0;
  99                 if (read_write == I2C_SMBUS_WRITE) {
 100                         mt_params[3].type = ACPI_TYPE_INTEGER;
 101                         mt_params[3].integer.value = 0;
 102                         mt_params[4].type = ACPI_TYPE_INTEGER;
 103                         mt_params[4].integer.value = 0;
 104                 }
 105                 break;
 106
 107         case I2C_SMBUS_BYTE:
 108                 protocol = ACPI_SMBUS_PRTCL_BYTE;
 109                 if (read_write == I2C_SMBUS_WRITE) {
 110                         mt_params[3].type = ACPI_TYPE_INTEGER;
 111                         mt_params[3].integer.value = 0;
 112                         mt_params[4].type = ACPI_TYPE_INTEGER;
 113                         mt_params[4].integer.value = 0;
 114                 } else {
 115                         command = 0;
 116                 }
 117                 break;
 118
 119         case I2C_SMBUS_BYTE_DATA:
 120                 protocol = ACPI_SMBUS_PRTCL_BYTE_DATA;
 121                 if (read_write == I2C_SMBUS_WRITE) {
 122                         mt_params[3].type = ACPI_TYPE_INTEGER;
 123                         mt_params[3].integer.value = 1;
 124                         mt_params[4].type = ACPI_TYPE_INTEGER;
 125                         mt_params[4].integer.value = data->byte;
 126                 }
 127                 break;
 128
 129         case I2C_SMBUS_WORD_DATA:
 130                 protocol = ACPI_SMBUS_PRTCL_WORD_DATA;
 131                 if (read_write == I2C_SMBUS_WRITE) {
 132                         mt_params[3].type = ACPI_TYPE_INTEGER;
 133                         mt_params[3].integer.value = 2;
 134                         mt_params[4].type = ACPI_TYPE_INTEGER;
 135                         mt_params[4].integer.value = data->word;
 136                 }
 137                 break;
 138
 139         case I2C_SMBUS_BLOCK_DATA:
 140                 protocol = ACPI_SMBUS_PRTCL_BLOCK_DATA;
 141                 if (read_write == I2C_SMBUS_WRITE) {
 142                         len = data->block[0];
 143                         if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 144                                 return -EINVAL;
 145                         mt_params[3].type = ACPI_TYPE_INTEGER;
 146                         mt_params[3].integer.value = len;
 147                         mt_params[4].type = ACPI_TYPE_BUFFER;
 148                         mt_params[4].buffer.length = len;
 149                         mt_params[4].buffer.pointer = data->block + 1;
 150                 }
 151                 break;
 152
 153         default:
 154                 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 155                 return -EOPNOTSUPP;
 156         }
 157
 158         if (read_write == I2C_SMBUS_READ) {
 159                 protocol |= ACPI_SMBUS_PRTCL_READ;
 160                 method = smbus_cmi->methods->mt_sbr;
 161                 input.count = 3;
 162         } else {
 163                 protocol |= ACPI_SMBUS_PRTCL_WRITE;
 164                 method = smbus_cmi->methods->mt_sbw;
 165                 input.count = 5;
 166         }
 167
 168         input.pointer = mt_params;
 169         mt_params[0].type = ACPI_TYPE_INTEGER;
 170         mt_params[0].integer.value = protocol;
 171         mt_params[1].type = ACPI_TYPE_INTEGER;
 172         mt_params[1].integer.value = addr;
 173         mt_params[2].type = ACPI_TYPE_INTEGER;
 174         mt_params[2].integer.value = command;
 175
 176         status = acpi_evaluate_object(smbus_cmi->handle, method, &input,
 177                                       &buffer);
 178         if (ACPI_FAILURE(status)) {
 179                 acpi_handle_err(smbus_cmi->handle,
 180                                 "Failed to evaluate %s: %i\n", method, status);
 181                 return -EIO;
 182         }
 183
 184         pkg = buffer.pointer;
 185         if (pkg && pkg->type == ACPI_TYPE_PACKAGE)
 186                 obj = pkg->package.elements;
 187         else {
 188                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 189                 result = -EIO;
 190                 goto out;
 191         }
 192         if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 193                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 194                 result = -EIO;
 195                 goto out;
 196         }
 197
 198         result = obj->integer.value;
 199         acpi_handle_debug(smbus_cmi->handle,  "%s return status: %i\n", method,
 200                           result);
 201
 202         switch (result) {
 203         case ACPI_SMBUS_STATUS_OK:
 204                 result = 0;
 205                 break;
 206         case ACPI_SMBUS_STATUS_BUSY:
 207                 result = -EBUSY;
 208                 goto out;
 209         case ACPI_SMBUS_STATUS_TIMEOUT:
 210                 result = -ETIMEDOUT;
 211                 goto out;
 212         case ACPI_SMBUS_STATUS_DNAK:
 213                 result = -ENXIO;
 214                 goto out;
 215         default:
 216                 result = -EIO;
 217                 goto out;
 218         }
 219
 220         if (read_write == I2C_SMBUS_WRITE || size == I2C_SMBUS_QUICK)
 221                 goto out;
 222
 223         obj = pkg->package.elements + 1;
 224         if (obj->type != ACPI_TYPE_INTEGER) {
 225                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 226                 result = -EIO;
 227                 goto out;
 228         }
 229
 230         len = obj->integer.value;
 231         obj = pkg->package.elements + 2;
 232         switch (size) {
 233         case I2C_SMBUS_BYTE:
 234         case I2C_SMBUS_BYTE_DATA:
 235         case I2C_SMBUS_WORD_DATA:
 236                 if (obj->type != ACPI_TYPE_INTEGER) {
 237                         acpi_handle_err(smbus_cmi->handle,
 238                                         "Invalid argument type\n");
 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_handle_err(smbus_cmi->handle,
 250                                         "Invalid argument type\n");
 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         struct acpi_handle *handle = smbus_cmi->handle;
 301         union acpi_object *obj;
 302         acpi_status status;
 303
 304         if (!strcmp(name, smbus_cmi->methods->mt_info)) {
 305                 status = acpi_evaluate_object(smbus_cmi->handle,
 306                                         smbus_cmi->methods->mt_info,
 307                                         NULL, &buffer);
 308                 if (ACPI_FAILURE(status)) {
 309                         acpi_handle_err(handle, "Failed to evaluate %s: %i\n",
 310                                         smbus_cmi->methods->mt_info, status);
 311                         return -EIO;
 312                 }
 313
 314                 obj = buffer.pointer;
 315                 if (obj && obj->type == ACPI_TYPE_PACKAGE)
 316                         obj = obj->package.elements;
 317                 else {
 318                         acpi_handle_err(handle, "Invalid argument type\n");
 319                         kfree(buffer.pointer);
 320                         return -EIO;
 321                 }
 322
 323                 if (obj->type != ACPI_TYPE_INTEGER) {
 324                         acpi_handle_err(handle, "Invalid argument type\n");
 325                         kfree(buffer.pointer);
 326                         return -EIO;
 327                 } else
 328                         acpi_handle_debug(handle, "SMBus CMI Version %x\n",
 329                                           (int)obj->integer.value);
 330
 331                 kfree(buffer.pointer);
 332                 smbus_cmi->cap_info = 1;
 333         } else if (!strcmp(name, smbus_cmi->methods->mt_sbr))
 334                 smbus_cmi->cap_read = 1;
 335         else if (!strcmp(name, smbus_cmi->methods->mt_sbw))
 336                 smbus_cmi->cap_write = 1;
 337         else
 338                 acpi_handle_debug(handle, "Unsupported CMI method: %s\n", 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 smbus_cmi_probe(struct platform_device *device)
 360 {
 361         struct device *dev = &device->dev;
 362         struct acpi_smbus_cmi *smbus_cmi;
 363         int ret;
 364
 365         smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
 366         if (!smbus_cmi)
 367                 return -ENOMEM;
 368
 369         smbus_cmi->handle = ACPI_HANDLE(dev);
 370         smbus_cmi->methods = device_get_match_data(dev);
 371
 372         platform_set_drvdata(device, smbus_cmi);
 373
 374         smbus_cmi->cap_info = 0;
 375         smbus_cmi->cap_read = 0;
 376         smbus_cmi->cap_write = 0;
 377
 378         acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
 379                             acpi_smbus_cmi_query_methods, NULL, smbus_cmi, NULL);
 380
 381         if (smbus_cmi->cap_info == 0) {
 382                 ret = -ENODEV;
 383                 goto err;
 384         }
 385
 386         snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
 387                  "SMBus CMI adapter %s", dev_name(dev));
 388         smbus_cmi->adapter.owner = THIS_MODULE;
 389         smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
 390         smbus_cmi->adapter.algo_data = smbus_cmi;
 391         smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 392         smbus_cmi->adapter.dev.parent = &device->dev;
 393
 394         ret = i2c_add_adapter(&smbus_cmi->adapter);
 395         if (ret) {
 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         return ret;
 405 }
 406
 407 static void smbus_cmi_remove(struct platform_device *device)
 408 {
 409         struct acpi_smbus_cmi *smbus_cmi = platform_get_drvdata(device);
 410
 411         i2c_del_adapter(&smbus_cmi->adapter);
 412         kfree(smbus_cmi);
 413 }
 414
 415 static struct platform_driver smbus_cmi_driver = {
 416         .probe = smbus_cmi_probe,
 417         .remove_new = smbus_cmi_remove,
 418         .driver = {
 419                 .name   = "smbus_cmi",
 420                 .acpi_match_table = acpi_smbus_cmi_ids,
 421         },
 422 };
 423 module_platform_driver(smbus_cmi_driver);
 424
 425 MODULE_LICENSE("GPL");
 426 MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
 427 MODULE_DESCRIPTION("ACPI SMBus CMI driver");