drivers/acpi/sbshc.c

   1 /*
   2  * SMBus driver for ACPI Embedded Controller (v0.1)
   3  *
   4  * Copyright (c) 2007 Alexey Starikovskiy
   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 <acpi/acpi_bus.h>
  12 #include <acpi/acpi_drivers.h>
  13 #include <acpi/actypes.h>
  14 #include <linux/wait.h>
  15 #include <linux/delay.h>
  16 #include <linux/interrupt.h>
  17 #include "sbshc.h"
  18
  19 #define ACPI_SMB_HC_CLASS       "smbus_host_controller"
  20 #define ACPI_SMB_HC_DEVICE_NAME "ACPI SMBus HC"
  21
  22 struct acpi_smb_hc {
  23         struct acpi_ec *ec;
  24         struct mutex lock;
  25         wait_queue_head_t wait;
  26         u8 offset;
  27         u8 query_bit;
  28         smbus_alarm_callback callback;
  29         void *context;
  30 };
  31
  32 static int acpi_smbus_hc_add(struct acpi_device *device);
  33 static int acpi_smbus_hc_remove(struct acpi_device *device, int type);
  34
  35 static const struct acpi_device_id sbs_device_ids[] = {
  36         {"ACPI0001", 0},
  37         {"ACPI0005", 0},
  38         {"", 0},
  39 };
  40
  41 MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
  42
  43 static struct acpi_driver acpi_smb_hc_driver = {
  44         .name = "smbus_hc",
  45         .class = ACPI_SMB_HC_CLASS,
  46         .ids = sbs_device_ids,
  47         .ops = {
  48                 .add = acpi_smbus_hc_add,
  49                 .remove = acpi_smbus_hc_remove,
  50                 },
  51 };
  52
  53 union acpi_smb_status {
  54         u8 raw;
  55         struct {
  56                 u8 status:5;
  57                 u8 reserved:1;
  58                 u8 alarm:1;
  59                 u8 done:1;
  60         } fields;
  61 };
  62
  63 enum acpi_smb_status_codes {
  64         SMBUS_OK = 0,
  65         SMBUS_UNKNOWN_FAILURE = 0x07,
  66         SMBUS_DEVICE_ADDRESS_NACK = 0x10,
  67         SMBUS_DEVICE_ERROR = 0x11,
  68         SMBUS_DEVICE_COMMAND_ACCESS_DENIED = 0x12,
  69         SMBUS_UNKNOWN_ERROR = 0x13,
  70         SMBUS_DEVICE_ACCESS_DENIED = 0x17,
  71         SMBUS_TIMEOUT = 0x18,
  72         SMBUS_HOST_UNSUPPORTED_PROTOCOL = 0x19,
  73         SMBUS_BUSY = 0x1a,
  74         SMBUS_PEC_ERROR = 0x1f,
  75 };
  76
  77 enum acpi_smb_offset {
  78         ACPI_SMB_PROTOCOL = 0,  /* protocol, PEC */
  79         ACPI_SMB_STATUS = 1,    /* status */
  80         ACPI_SMB_ADDRESS = 2,   /* address */
  81         ACPI_SMB_COMMAND = 3,   /* command */
  82         ACPI_SMB_DATA = 4,      /* 32 data registers */
  83         ACPI_SMB_BLOCK_COUNT = 0x24,    /* number of data bytes */
  84         ACPI_SMB_ALARM_ADDRESS = 0x25,  /* alarm address */
  85         ACPI_SMB_ALARM_DATA = 0x26,     /* 2 bytes alarm data */
  86 };
  87
  88 static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
  89 {
  90         return ec_read(hc->offset + address, data);
  91 }
  92
  93 static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
  94 {
  95         return ec_write(hc->offset + address, data);
  96 }
  97
  98 static inline int smb_check_done(struct acpi_smb_hc *hc)
  99 {
 100         union acpi_smb_status status = {.raw = 0};
 101         smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw);
 102         return status.fields.done && (status.fields.status == SMBUS_OK);
 103 }
 104
 105 static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
 106 {
 107         if (wait_event_timeout(hc->wait, smb_check_done(hc),
 108                                msecs_to_jiffies(timeout)))
 109                 return 0;
 110         /*
 111          * After the timeout happens, OS will try to check the status of SMbus.
 112          * If the status is what OS expected, it will be regarded as the bogus
 113          * timeout.
 114          */
 115         if (smb_check_done(hc))
 116                 return 0;
 117         else
 118                 return -ETIME;
 119 }
 120
 121 static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
 122                                   u8 address, u8 command, u8 *data, u8 length)
 123 {
 124         int ret = -EFAULT, i;
 125         u8 temp, sz = 0;
 126
 127         if (!hc) {
 128                 printk(KERN_ERR PREFIX "host controller is not configured\n");
 129                 return ret;
 130         }
 131
 132         mutex_lock(&hc->lock);
 133         if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
 134                 goto end;
 135         if (temp) {
 136                 ret = -EBUSY;
 137                 goto end;
 138         }
 139         smb_hc_write(hc, ACPI_SMB_COMMAND, command);
 140         if (!(protocol & 0x01)) {
 141                 smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
 142                 for (i = 0; i < length; ++i)
 143                         smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
 144         }
 145         smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
 146         smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
 147         /*
 148          * Wait for completion. Save the status code, data size,
 149          * and data into the return package (if required by the protocol).
 150          */
 151         ret = wait_transaction_complete(hc, 1000);
 152         if (ret || !(protocol & 0x01))
 153                 goto end;
 154         switch (protocol) {
 155         case SMBUS_RECEIVE_BYTE:
 156         case SMBUS_READ_BYTE:
 157                 sz = 1;
 158                 break;
 159         case SMBUS_READ_WORD:
 160                 sz = 2;
 161                 break;
 162         case SMBUS_READ_BLOCK:
 163                 if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
 164                         ret = -EFAULT;
 165                         goto end;
 166                 }
 167                 sz &= 0x1f;
 168                 break;
 169         }
 170         for (i = 0; i < sz; ++i)
 171                 smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
 172       end:
 173         mutex_unlock(&hc->lock);
 174         return ret;
 175 }
 176
 177 int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
 178                     u8 command, u8 *data)
 179 {
 180         return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
 181 }
 182
 183 EXPORT_SYMBOL_GPL(acpi_smbus_read);
 184
 185 int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
 186                      u8 command, u8 *data, u8 length)
 187 {
 188         return acpi_smbus_transaction(hc, protocol, address, command, data, length);
 189 }
 190
 191 EXPORT_SYMBOL_GPL(acpi_smbus_write);
 192
 193 int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
 194                                  smbus_alarm_callback callback, void *context)
 195 {
 196         mutex_lock(&hc->lock);
 197         hc->callback = callback;
 198         hc->context = context;
 199         mutex_unlock(&hc->lock);
 200         return 0;
 201 }
 202
 203 EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
 204
 205 int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
 206 {
 207         mutex_lock(&hc->lock);
 208         hc->callback = NULL;
 209         hc->context = NULL;
 210         mutex_unlock(&hc->lock);
 211         return 0;
 212 }
 213
 214 EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
 215
 216 static inline void acpi_smbus_callback(void *context)
 217 {
 218         struct acpi_smb_hc *hc = context;
 219         if (hc->callback)
 220                 hc->callback(hc->context);
 221 }
 222
 223 static int smbus_alarm(void *context)
 224 {
 225         struct acpi_smb_hc *hc = context;
 226         union acpi_smb_status status;
 227         u8 address;
 228         if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
 229                 return 0;
 230         /* Check if it is only a completion notify */
 231         if (status.fields.done)
 232                 wake_up(&hc->wait);
 233         if (!status.fields.alarm)
 234                 return 0;
 235         mutex_lock(&hc->lock);
 236         smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
 237         status.fields.alarm = 0;
 238         smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
 239         /* We are only interested in events coming from known devices */
 240         switch (address >> 1) {
 241                 case ACPI_SBS_CHARGER:
 242                 case ACPI_SBS_MANAGER:
 243                 case ACPI_SBS_BATTERY:
 244                         acpi_os_execute(OSL_GPE_HANDLER,
 245                                         acpi_smbus_callback, hc);
 246                 default:;
 247         }
 248         mutex_unlock(&hc->lock);
 249         return 0;
 250 }
 251
 252 typedef int (*acpi_ec_query_func) (void *data);
 253
 254 extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
 255                               acpi_handle handle, acpi_ec_query_func func,
 256                               void *data);
 257
 258 static int acpi_smbus_hc_add(struct acpi_device *device)
 259 {
 260         int status;
 261         unsigned long long val;
 262         struct acpi_smb_hc *hc;
 263
 264         if (!device)
 265                 return -EINVAL;
 266
 267         status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
 268         if (ACPI_FAILURE(status)) {
 269                 printk(KERN_ERR PREFIX "error obtaining _EC.\n");
 270                 return -EIO;
 271         }
 272
 273         strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
 274         strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
 275
 276         hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
 277         if (!hc)
 278                 return -ENOMEM;
 279         mutex_init(&hc->lock);
 280         init_waitqueue_head(&hc->wait);
 281
 282         hc->ec = acpi_driver_data(device->parent);
 283         hc->offset = (val >> 8) & 0xff;
 284         hc->query_bit = val & 0xff;
 285         device->driver_data = hc;
 286
 287         acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
 288         printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
 289                 hc->ec, hc->offset, hc->query_bit);
 290
 291         return 0;
 292 }
 293
 294 extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
 295
 296 static int acpi_smbus_hc_remove(struct acpi_device *device, int type)
 297 {
 298         struct acpi_smb_hc *hc;
 299
 300         if (!device)
 301                 return -EINVAL;
 302
 303         hc = acpi_driver_data(device);
 304         acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
 305         kfree(hc);
 306         device->driver_data = NULL;
 307         return 0;
 308 }
 309
 310 static int __init acpi_smb_hc_init(void)
 311 {
 312         int result;
 313
 314         result = acpi_bus_register_driver(&acpi_smb_hc_driver);
 315         if (result < 0)
 316                 return -ENODEV;
 317         return 0;
 318 }
 319
 320 static void __exit acpi_smb_hc_exit(void)
 321 {
 322         acpi_bus_unregister_driver(&acpi_smb_hc_driver);
 323 }
 324
 325 module_init(acpi_smb_hc_init);
 326 module_exit(acpi_smb_hc_exit);
 327
 328 MODULE_LICENSE("GPL");
 329 MODULE_AUTHOR("Alexey Starikovskiy");
 330 MODULE_DESCRIPTION("ACPI SMBus HC driver");