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