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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 <linux/dmi.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);
 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 bool macbook;
 92 
 93 static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
 94 {
 95         return ec_read(hc->offset + address, data);
 96 }
 97 
 98 static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
 99 {
100         return ec_write(hc->offset + address, data);
101 }
102 
103 static inline int smb_check_done(struct acpi_smb_hc *hc)
104 {
105         union acpi_smb_status status = {.raw = 0};
106         smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw);
107         return status.fields.done && (status.fields.status == SMBUS_OK);
108 }
109 
110 static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
111 {
112         if (wait_event_timeout(hc->wait, smb_check_done(hc),
113                                msecs_to_jiffies(timeout)))
114                 return 0;
115         /*
116          * After the timeout happens, OS will try to check the status of SMbus.
117          * If the status is what OS expected, it will be regarded as the bogus
118          * timeout.
119          */
120         if (smb_check_done(hc))
121                 return 0;
122         else
123                 return -ETIME;
124 }
125 
126 static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
127                                   u8 address, u8 command, u8 *data, u8 length)
128 {
129         int ret = -EFAULT, i;
130         u8 temp, sz = 0;
131 
132         if (!hc) {
133                 printk(KERN_ERR PREFIX "host controller is not configured\n");
134                 return ret;
135         }
136 
137         mutex_lock(&hc->lock);
138         if (macbook)
139                 udelay(5);
140         if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
141                 goto end;
142         if (temp) {
143                 ret = -EBUSY;
144                 goto end;
145         }
146         smb_hc_write(hc, ACPI_SMB_COMMAND, command);
147         if (!(protocol & 0x01)) {
148                 smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
149                 for (i = 0; i < length; ++i)
150                         smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
151         }
152         smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
153         smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
154         /*
155          * Wait for completion. Save the status code, data size,
156          * and data into the return package (if required by the protocol).
157          */
158         ret = wait_transaction_complete(hc, 1000);
159         if (ret || !(protocol & 0x01))
160                 goto end;
161         switch (protocol) {
162         case SMBUS_RECEIVE_BYTE:
163         case SMBUS_READ_BYTE:
164                 sz = 1;
165                 break;
166         case SMBUS_READ_WORD:
167                 sz = 2;
168                 break;
169         case SMBUS_READ_BLOCK:
170                 if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
171                         ret = -EFAULT;
172                         goto end;
173                 }
174                 sz &= 0x1f;
175                 break;
176         }
177         for (i = 0; i < sz; ++i)
178                 smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
179       end:
180         mutex_unlock(&hc->lock);
181         return ret;
182 }
183 
184 int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
185                     u8 command, u8 *data)
186 {
187         return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
188 }
189 
190 EXPORT_SYMBOL_GPL(acpi_smbus_read);
191 
192 int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
193                      u8 command, u8 *data, u8 length)
194 {
195         return acpi_smbus_transaction(hc, protocol, address, command, data, length);
196 }
197 
198 EXPORT_SYMBOL_GPL(acpi_smbus_write);
199 
200 int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
201                                  smbus_alarm_callback callback, void *context)
202 {
203         mutex_lock(&hc->lock);
204         hc->callback = callback;
205         hc->context = context;
206         mutex_unlock(&hc->lock);
207         return 0;
208 }
209 
210 EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
211 
212 int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
213 {
214         mutex_lock(&hc->lock);
215         hc->callback = NULL;
216         hc->context = NULL;
217         mutex_unlock(&hc->lock);
218         return 0;
219 }
220 
221 EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
222 
223 static inline void acpi_smbus_callback(void *context)
224 {
225         struct acpi_smb_hc *hc = context;
226         if (hc->callback)
227                 hc->callback(hc->context);
228 }
229 
230 static int smbus_alarm(void *context)
231 {
232         struct acpi_smb_hc *hc = context;
233         union acpi_smb_status status;
234         u8 address;
235         if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
236                 return 0;
237         /* Check if it is only a completion notify */
238         if (status.fields.done)
239                 wake_up(&hc->wait);
240         if (!status.fields.alarm)
241                 return 0;
242         mutex_lock(&hc->lock);
243         smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
244         status.fields.alarm = 0;
245         smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
246         /* We are only interested in events coming from known devices */
247         switch (address >> 1) {
248                 case ACPI_SBS_CHARGER:
249                 case ACPI_SBS_MANAGER:
250                 case ACPI_SBS_BATTERY:
251                         acpi_os_execute(OSL_NOTIFY_HANDLER,
252                                         acpi_smbus_callback, hc);
253                 default:;
254         }
255         mutex_unlock(&hc->lock);
256         return 0;
257 }
258 
259 typedef int (*acpi_ec_query_func) (void *data);
260 
261 extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
262                               acpi_handle handle, acpi_ec_query_func func,
263                               void *data);
264 
265 static int macbook_dmi_match(const struct dmi_system_id *d)
266 {
267         pr_debug("Detected MacBook, enabling workaround\n");
268         macbook = true;
269         return 0;
270 }
271 
272 static struct dmi_system_id acpi_smbus_dmi_table[] = {
273         { macbook_dmi_match, "Apple MacBook", {
274           DMI_MATCH(DMI_BOARD_VENDOR, "Apple"),
275           DMI_MATCH(DMI_PRODUCT_NAME, "MacBook") },
276         },
277         { },
278 };
279 
280 static int acpi_smbus_hc_add(struct acpi_device *device)
281 {
282         int status;
283         unsigned long long val;
284         struct acpi_smb_hc *hc;
285 
286         dmi_check_system(acpi_smbus_dmi_table);
287 
288         if (!device)
289                 return -EINVAL;
290 
291         status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
292         if (ACPI_FAILURE(status)) {
293                 printk(KERN_ERR PREFIX "error obtaining _EC.\n");
294                 return -EIO;
295         }
296 
297         strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
298         strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
299 
300         hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
301         if (!hc)
302                 return -ENOMEM;
303         mutex_init(&hc->lock);
304         init_waitqueue_head(&hc->wait);
305 
306         hc->ec = acpi_driver_data(device->parent);
307         hc->offset = (val >> 8) & 0xff;
308         hc->query_bit = val & 0xff;
309         device->driver_data = hc;
310 
311         acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
312         printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
313                 hc->ec, hc->offset, hc->query_bit);
314 
315         return 0;
316 }
317 
318 extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
319 
320 static int acpi_smbus_hc_remove(struct acpi_device *device)
321 {
322         struct acpi_smb_hc *hc;
323 
324         if (!device)
325                 return -EINVAL;
326 
327         hc = acpi_driver_data(device);
328         acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
329         kfree(hc);
330         device->driver_data = NULL;
331         return 0;
332 }
333 
334 module_acpi_driver(acpi_smb_hc_driver);
335 
336 MODULE_LICENSE("GPL");
337 MODULE_AUTHOR("Alexey Starikovskiy");
338 MODULE_DESCRIPTION("ACPI SMBus HC driver");
339 

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