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