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 struct smbus_methods_t {
  17         char *mt_info;
  18         char *mt_sbr;
  19         char *mt_sbw;
  20 };
  21
  22 struct acpi_smbus_cmi {
  23         acpi_handle handle;
  24         struct i2c_adapter adapter;
  25         u8 cap_info:1;
  26         u8 cap_read:1;
  27         u8 cap_write:1;
  28         const struct smbus_methods_t *methods;
  29 };
  30
  31 static const struct smbus_methods_t smbus_methods = {
  32         .mt_info = "_SBI",
  33         .mt_sbr  = "_SBR",
  34         .mt_sbw  = "_SBW",
  35 };
  36
  37 /* Some IBM BIOSes omit the leading underscore */
  38 static const struct smbus_methods_t ibm_smbus_methods = {
  39         .mt_info = "SBI_",
  40         .mt_sbr  = "SBR_",
  41         .mt_sbw  = "SBW_",
  42 };
  43
  44 static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
  45         {"SMBUS01", (kernel_ulong_t)&smbus_methods},
  46         {ACPI_SMBUS_IBM_HID, (kernel_ulong_t)&ibm_smbus_methods},
  47         {ACPI_SMBUS_MS_HID, (kernel_ulong_t)&smbus_methods},
  48         {"", 0}
  49 };
  50 MODULE_DEVICE_TABLE(acpi, acpi_smbus_cmi_ids);
  51
  52 #define ACPI_SMBUS_STATUS_OK                    0x00
  53 #define ACPI_SMBUS_STATUS_FAIL                  0x07
  54 #define ACPI_SMBUS_STATUS_DNAK                  0x10
  55 #define ACPI_SMBUS_STATUS_DERR                  0x11
  56 #define ACPI_SMBUS_STATUS_CMD_DENY              0x12
  57 #define ACPI_SMBUS_STATUS_UNKNOWN               0x13
  58 #define ACPI_SMBUS_STATUS_ACC_DENY              0x17
  59 #define ACPI_SMBUS_STATUS_TIMEOUT               0x18
  60 #define ACPI_SMBUS_STATUS_NOTSUP                0x19
  61 #define ACPI_SMBUS_STATUS_BUSY                  0x1a
  62 #define ACPI_SMBUS_STATUS_PEC                   0x1f
  63
  64 #define ACPI_SMBUS_PRTCL_WRITE                  0x00
  65 #define ACPI_SMBUS_PRTCL_READ                   0x01
  66 #define ACPI_SMBUS_PRTCL_QUICK                  0x02
  67 #define ACPI_SMBUS_PRTCL_BYTE                   0x04
  68 #define ACPI_SMBUS_PRTCL_BYTE_DATA              0x06
  69 #define ACPI_SMBUS_PRTCL_WORD_DATA              0x08
  70 #define ACPI_SMBUS_PRTCL_BLOCK_DATA             0x0a
  71
  72
  73 static int
  74 acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
  75                    char read_write, u8 command, int size,
  76                    union i2c_smbus_data *data)
  77 {
  78         int result = 0;
  79         struct acpi_smbus_cmi *smbus_cmi = adap->algo_data;
  80         unsigned char protocol;
  81         acpi_status status = 0;
  82         struct acpi_object_list input;
  83         union acpi_object mt_params[5];
  84         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  85         union acpi_object *obj;
  86         union acpi_object *pkg;
  87         char *method;
  88         int len = 0;
  89
  90         dev_dbg(&adap->dev, "access size: %d %s\n", size,
  91                 (read_write) ? "READ" : "WRITE");
  92         switch (size) {
  93         case I2C_SMBUS_QUICK:
  94                 protocol = ACPI_SMBUS_PRTCL_QUICK;
  95                 command = 0;
  96                 if (read_write == I2C_SMBUS_WRITE) {
  97                         mt_params[3].type = ACPI_TYPE_INTEGER;
  98                         mt_params[3].integer.value = 0;
  99                         mt_params[4].type = ACPI_TYPE_INTEGER;
 100                         mt_params[4].integer.value = 0;
 101                 }
 102                 break;
 103
 104         case I2C_SMBUS_BYTE:
 105                 protocol = ACPI_SMBUS_PRTCL_BYTE;
 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                 } else {
 112                         command = 0;
 113                 }
 114                 break;
 115
 116         case I2C_SMBUS_BYTE_DATA:
 117                 protocol = ACPI_SMBUS_PRTCL_BYTE_DATA;
 118                 if (read_write == I2C_SMBUS_WRITE) {
 119                         mt_params[3].type = ACPI_TYPE_INTEGER;
 120                         mt_params[3].integer.value = 1;
 121                         mt_params[4].type = ACPI_TYPE_INTEGER;
 122                         mt_params[4].integer.value = data->byte;
 123                 }
 124                 break;
 125
 126         case I2C_SMBUS_WORD_DATA:
 127                 protocol = ACPI_SMBUS_PRTCL_WORD_DATA;
 128                 if (read_write == I2C_SMBUS_WRITE) {
 129                         mt_params[3].type = ACPI_TYPE_INTEGER;
 130                         mt_params[3].integer.value = 2;
 131                         mt_params[4].type = ACPI_TYPE_INTEGER;
 132                         mt_params[4].integer.value = data->word;
 133                 }
 134                 break;
 135
 136         case I2C_SMBUS_BLOCK_DATA:
 137                 protocol = ACPI_SMBUS_PRTCL_BLOCK_DATA;
 138                 if (read_write == I2C_SMBUS_WRITE) {
 139                         len = data->block[0];
 140                         if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 141                                 return -EINVAL;
 142                         mt_params[3].type = ACPI_TYPE_INTEGER;
 143                         mt_params[3].integer.value = len;
 144                         mt_params[4].type = ACPI_TYPE_BUFFER;
 145                         mt_params[4].buffer.length = len;
 146                         mt_params[4].buffer.pointer = data->block + 1;
 147                 }
 148                 break;
 149
 150         default:
 151                 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 152                 return -EOPNOTSUPP;
 153         }
 154
 155         if (read_write == I2C_SMBUS_READ) {
 156                 protocol |= ACPI_SMBUS_PRTCL_READ;
 157                 method = smbus_cmi->methods->mt_sbr;
 158                 input.count = 3;
 159         } else {
 160                 protocol |= ACPI_SMBUS_PRTCL_WRITE;
 161                 method = smbus_cmi->methods->mt_sbw;
 162                 input.count = 5;
 163         }
 164
 165         input.pointer = mt_params;
 166         mt_params[0].type = ACPI_TYPE_INTEGER;
 167         mt_params[0].integer.value = protocol;
 168         mt_params[1].type = ACPI_TYPE_INTEGER;
 169         mt_params[1].integer.value = addr;
 170         mt_params[2].type = ACPI_TYPE_INTEGER;
 171         mt_params[2].integer.value = command;
 172
 173         status = acpi_evaluate_object(smbus_cmi->handle, method, &input,
 174                                       &buffer);
 175         if (ACPI_FAILURE(status)) {
 176                 acpi_handle_err(smbus_cmi->handle,
 177                                 "Failed to evaluate %s: %i\n", method, status);
 178                 return -EIO;
 179         }
 180
 181         pkg = buffer.pointer;
 182         if (pkg && pkg->type == ACPI_TYPE_PACKAGE)
 183                 obj = pkg->package.elements;
 184         else {
 185                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 186                 result = -EIO;
 187                 goto out;
 188         }
 189         if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 190                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 191                 result = -EIO;
 192                 goto out;
 193         }
 194
 195         result = obj->integer.value;
 196         acpi_handle_debug(smbus_cmi->handle,  "%s return status: %i\n", method,
 197                           result);
 198
 199         switch (result) {
 200         case ACPI_SMBUS_STATUS_OK:
 201                 result = 0;
 202                 break;
 203         case ACPI_SMBUS_STATUS_BUSY:
 204                 result = -EBUSY;
 205                 goto out;
 206         case ACPI_SMBUS_STATUS_TIMEOUT:
 207                 result = -ETIMEDOUT;
 208                 goto out;
 209         case ACPI_SMBUS_STATUS_DNAK:
 210                 result = -ENXIO;
 211                 goto out;
 212         default:
 213                 result = -EIO;
 214                 goto out;
 215         }
 216
 217         if (read_write == I2C_SMBUS_WRITE || size == I2C_SMBUS_QUICK)
 218                 goto out;
 219
 220         obj = pkg->package.elements + 1;
 221         if (obj->type != ACPI_TYPE_INTEGER) {
 222                 acpi_handle_err(smbus_cmi->handle, "Invalid argument type\n");
 223                 result = -EIO;
 224                 goto out;
 225         }
 226
 227         len = obj->integer.value;
 228         obj = pkg->package.elements + 2;
 229         switch (size) {
 230         case I2C_SMBUS_BYTE:
 231         case I2C_SMBUS_BYTE_DATA:
 232         case I2C_SMBUS_WORD_DATA:
 233                 if (obj->type != ACPI_TYPE_INTEGER) {
 234                         acpi_handle_err(smbus_cmi->handle,
 235                                         "Invalid argument type\n");
 236                         result = -EIO;
 237                         goto out;
 238                 }
 239                 if (len == 2)
 240                         data->word = obj->integer.value;
 241                 else
 242                         data->byte = obj->integer.value;
 243                 break;
 244         case I2C_SMBUS_BLOCK_DATA:
 245                 if (obj->type != ACPI_TYPE_BUFFER) {
 246                         acpi_handle_err(smbus_cmi->handle,
 247                                         "Invalid argument type\n");
 248                         result = -EIO;
 249                         goto out;
 250                 }
 251                 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 252                         return -EPROTO;
 253                 data->block[0] = len;
 254                 memcpy(data->block + 1, obj->buffer.pointer, len);
 255                 break;
 256         }
 257
 258 out:
 259         kfree(buffer.pointer);
 260         dev_dbg(&adap->dev, "Transaction status: %i\n", result);
 261         return result;
 262 }
 263
 264 static u32 acpi_smbus_cmi_func(struct i2c_adapter *adapter)
 265 {
 266         struct acpi_smbus_cmi *smbus_cmi = adapter->algo_data;
 267         u32 ret;
 268
 269         ret = smbus_cmi->cap_read | smbus_cmi->cap_write ?
 270                 I2C_FUNC_SMBUS_QUICK : 0;
 271
 272         ret |= smbus_cmi->cap_read ?
 273                 (I2C_FUNC_SMBUS_READ_BYTE |
 274                 I2C_FUNC_SMBUS_READ_BYTE_DATA |
 275                 I2C_FUNC_SMBUS_READ_WORD_DATA |
 276                 I2C_FUNC_SMBUS_READ_BLOCK_DATA) : 0;
 277
 278         ret |= smbus_cmi->cap_write ?
 279                 (I2C_FUNC_SMBUS_WRITE_BYTE |
 280                 I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
 281                 I2C_FUNC_SMBUS_WRITE_WORD_DATA |
 282                 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) : 0;
 283
 284         return ret;
 285 }
 286
 287 static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
 288         .smbus_xfer = acpi_smbus_cmi_access,
 289         .functionality = acpi_smbus_cmi_func,
 290 };
 291
 292
 293 static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
 294                                   const char *name)
 295 {
 296         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 297         struct acpi_handle *handle = smbus_cmi->handle;
 298         union acpi_object *obj;
 299         acpi_status status;
 300
 301         if (!strcmp(name, smbus_cmi->methods->mt_info)) {
 302                 status = acpi_evaluate_object(smbus_cmi->handle,
 303                                         smbus_cmi->methods->mt_info,
 304                                         NULL, &buffer);
 305                 if (ACPI_FAILURE(status)) {
 306                         acpi_handle_err(handle, "Failed to evaluate %s: %i\n",
 307                                         smbus_cmi->methods->mt_info, status);
 308                         return -EIO;
 309                 }
 310
 311                 obj = buffer.pointer;
 312                 if (obj && obj->type == ACPI_TYPE_PACKAGE)
 313                         obj = obj->package.elements;
 314                 else {
 315                         acpi_handle_err(handle, "Invalid argument type\n");
 316                         kfree(buffer.pointer);
 317                         return -EIO;
 318                 }
 319
 320                 if (obj->type != ACPI_TYPE_INTEGER) {
 321                         acpi_handle_err(handle, "Invalid argument type\n");
 322                         kfree(buffer.pointer);
 323                         return -EIO;
 324                 } else
 325                         acpi_handle_debug(handle, "SMBus CMI Version %x\n",
 326                                           (int)obj->integer.value);
 327
 328                 kfree(buffer.pointer);
 329                 smbus_cmi->cap_info = 1;
 330         } else if (!strcmp(name, smbus_cmi->methods->mt_sbr))
 331                 smbus_cmi->cap_read = 1;
 332         else if (!strcmp(name, smbus_cmi->methods->mt_sbw))
 333                 smbus_cmi->cap_write = 1;
 334         else
 335                 acpi_handle_debug(handle, "Unsupported CMI method: %s\n", name);
 336
 337         return 0;
 338 }
 339
 340 static acpi_status acpi_smbus_cmi_query_methods(acpi_handle handle, u32 level,
 341                         void *context, void **return_value)
 342 {
 343         char node_name[5];
 344         struct acpi_buffer buffer = { sizeof(node_name), node_name };
 345         struct acpi_smbus_cmi *smbus_cmi = context;
 346         acpi_status status;
 347
 348         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 349
 350         if (ACPI_SUCCESS(status))
 351                 acpi_smbus_cmi_add_cap(smbus_cmi, node_name);
 352
 353         return AE_OK;
 354 }
 355
 356 static int smbus_cmi_probe(struct platform_device *device)
 357 {
 358         struct device *dev = &device->dev;
 359         struct acpi_smbus_cmi *smbus_cmi;
 360         int ret;
 361
 362         smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
 363         if (!smbus_cmi)
 364                 return -ENOMEM;
 365
 366         smbus_cmi->handle = ACPI_HANDLE(dev);
 367         smbus_cmi->methods = device_get_match_data(dev);
 368
 369         platform_set_drvdata(device, smbus_cmi);
 370
 371         smbus_cmi->cap_info = 0;
 372         smbus_cmi->cap_read = 0;
 373         smbus_cmi->cap_write = 0;
 374
 375         acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
 376                             acpi_smbus_cmi_query_methods, NULL, smbus_cmi, NULL);
 377
 378         if (smbus_cmi->cap_info == 0) {
 379                 ret = -ENODEV;
 380                 goto err;
 381         }
 382
 383         snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
 384                  "SMBus CMI adapter %s", dev_name(dev));
 385         smbus_cmi->adapter.owner = THIS_MODULE;
 386         smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
 387         smbus_cmi->adapter.algo_data = smbus_cmi;
 388         smbus_cmi->adapter.class = I2C_CLASS_HWMON;
 389         smbus_cmi->adapter.dev.parent = &device->dev;
 390
 391         ret = i2c_add_adapter(&smbus_cmi->adapter);
 392         if (ret) {
 393                 dev_err(&device->dev, "Couldn't register adapter!\n");
 394                 goto err;
 395         }
 396
 397         return 0;
 398
 399 err:
 400         kfree(smbus_cmi);
 401         return ret;
 402 }
 403
 404 static void smbus_cmi_remove(struct platform_device *device)
 405 {
 406         struct acpi_smbus_cmi *smbus_cmi = platform_get_drvdata(device);
 407
 408         i2c_del_adapter(&smbus_cmi->adapter);
 409         kfree(smbus_cmi);
 410 }
 411
 412 static struct platform_driver smbus_cmi_driver = {
 413         .probe = smbus_cmi_probe,
 414         .remove_new = smbus_cmi_remove,
 415         .driver = {
 416                 .name   = "smbus_cmi",
 417                 .acpi_match_table = acpi_smbus_cmi_ids,
 418         },
 419 };
 420 module_platform_driver(smbus_cmi_driver);
 421
 422 MODULE_LICENSE("GPL");
 423 MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
 424 MODULE_DESCRIPTION("ACPI SMBus CMI driver");