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Linux/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 <linux/acpi.h>
 12 #include <linux/wait.h>
 13 #include <linux/slab.h>
 14 #include <linux/delay.h>
 15 #include <linux/module.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);
 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)
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 module_acpi_driver(acpi_smb_hc_driver);
313 
314 MODULE_LICENSE("GPL");
315 MODULE_AUTHOR("Alexey Starikovskiy");
316 MODULE_DESCRIPTION("ACPI SMBus HC driver");
317 

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