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