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