Root/drivers/char/efirtc.c

1/*
2 * EFI Time Services Driver for Linux
3 *
4 * Copyright (C) 1999 Hewlett-Packard Co
5 * Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
6 *
7 * Based on skeleton from the drivers/char/rtc.c driver by P. Gortmaker
8 *
9 * This code provides an architected & portable interface to the real time
10 * clock by using EFI instead of direct bit fiddling. The functionalities are
11 * quite different from the rtc.c driver. The only way to talk to the device
12 * is by using ioctl(). There is a /proc interface which provides the raw
13 * information.
14 *
15 * Please note that we have kept the API as close as possible to the
16 * legacy RTC. The standard /sbin/hwclock program should work normally
17 * when used to get/set the time.
18 *
19 * NOTES:
20 * - Locking is required for safe execution of EFI calls with regards
21 * to interrupts and SMP.
22 *
23 * TODO (December 1999):
24 * - provide the API to set/get the WakeUp Alarm (different from the
25 * rtc.c alarm).
26 * - SMP testing
27 * - Add module support
28 */
29
30#include <linux/types.h>
31#include <linux/errno.h>
32#include <linux/miscdevice.h>
33#include <linux/module.h>
34#include <linux/init.h>
35#include <linux/rtc.h>
36#include <linux/proc_fs.h>
37#include <linux/efi.h>
38#include <linux/uaccess.h>
39
40
41#define EFI_RTC_VERSION "0.4"
42
43#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
44/*
45 * EFI Epoch is 1/1/1998
46 */
47#define EFI_RTC_EPOCH 1998
48
49static DEFINE_SPINLOCK(efi_rtc_lock);
50
51static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
52                            unsigned long arg);
53
54#define is_leap(year) \
55          ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
56
57static const unsigned short int __mon_yday[2][13] =
58{
59    /* Normal years. */
60    { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
61    /* Leap years. */
62    { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
63};
64
65/*
66 * returns day of the year [0-365]
67 */
68static inline int
69compute_yday(efi_time_t *eft)
70{
71    /* efi_time_t.month is in the [1-12] so, we need -1 */
72    return __mon_yday[is_leap(eft->year)][eft->month-1]+ eft->day -1;
73}
74/*
75 * returns day of the week [0-6] 0=Sunday
76 *
77 * Don't try to provide a year that's before 1998, please !
78 */
79static int
80compute_wday(efi_time_t *eft)
81{
82    int y;
83    int ndays = 0;
84
85    if ( eft->year < 1998 ) {
86        printk(KERN_ERR "efirtc: EFI year < 1998, invalid date\n");
87        return -1;
88    }
89
90    for(y=EFI_RTC_EPOCH; y < eft->year; y++ ) {
91        ndays += 365 + (is_leap(y) ? 1 : 0);
92    }
93    ndays += compute_yday(eft);
94
95    /*
96     * 4=1/1/1998 was a Thursday
97     */
98    return (ndays + 4) % 7;
99}
100
101static void
102convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)
103{
104
105    eft->year = wtime->tm_year + 1900;
106    eft->month = wtime->tm_mon + 1;
107    eft->day = wtime->tm_mday;
108    eft->hour = wtime->tm_hour;
109    eft->minute = wtime->tm_min;
110    eft->second = wtime->tm_sec;
111    eft->nanosecond = 0;
112    eft->daylight = wtime->tm_isdst ? EFI_ISDST: 0;
113    eft->timezone = EFI_UNSPECIFIED_TIMEZONE;
114}
115
116static void
117convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
118{
119    memset(wtime, 0, sizeof(*wtime));
120    wtime->tm_sec = eft->second;
121    wtime->tm_min = eft->minute;
122    wtime->tm_hour = eft->hour;
123    wtime->tm_mday = eft->day;
124    wtime->tm_mon = eft->month - 1;
125    wtime->tm_year = eft->year - 1900;
126
127    /* day of the week [0-6], Sunday=0 */
128    wtime->tm_wday = compute_wday(eft);
129
130    /* day in the year [1-365]*/
131    wtime->tm_yday = compute_yday(eft);
132
133
134    switch (eft->daylight & EFI_ISDST) {
135        case EFI_ISDST:
136            wtime->tm_isdst = 1;
137            break;
138        case EFI_TIME_ADJUST_DAYLIGHT:
139            wtime->tm_isdst = 0;
140            break;
141        default:
142            wtime->tm_isdst = -1;
143    }
144}
145
146static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
147                            unsigned long arg)
148{
149
150    efi_status_t status;
151    unsigned long flags;
152    efi_time_t eft;
153    efi_time_cap_t cap;
154    struct rtc_time wtime;
155    struct rtc_wkalrm __user *ewp;
156    unsigned char enabled, pending;
157
158    switch (cmd) {
159        case RTC_UIE_ON:
160        case RTC_UIE_OFF:
161        case RTC_PIE_ON:
162        case RTC_PIE_OFF:
163        case RTC_AIE_ON:
164        case RTC_AIE_OFF:
165        case RTC_ALM_SET:
166        case RTC_ALM_READ:
167        case RTC_IRQP_READ:
168        case RTC_IRQP_SET:
169        case RTC_EPOCH_READ:
170        case RTC_EPOCH_SET:
171            return -EINVAL;
172
173        case RTC_RD_TIME:
174            spin_lock_irqsave(&efi_rtc_lock, flags);
175
176            status = efi.get_time(&eft, &cap);
177
178            spin_unlock_irqrestore(&efi_rtc_lock,flags);
179
180            if (status != EFI_SUCCESS) {
181                /* should never happen */
182                printk(KERN_ERR "efitime: can't read time\n");
183                return -EINVAL;
184            }
185
186            convert_from_efi_time(&eft, &wtime);
187
188             return copy_to_user((void __user *)arg, &wtime,
189                        sizeof (struct rtc_time)) ? - EFAULT : 0;
190
191        case RTC_SET_TIME:
192
193            if (!capable(CAP_SYS_TIME)) return -EACCES;
194
195            if (copy_from_user(&wtime, (struct rtc_time __user *)arg,
196                       sizeof(struct rtc_time)) )
197                return -EFAULT;
198
199            convert_to_efi_time(&wtime, &eft);
200
201            spin_lock_irqsave(&efi_rtc_lock, flags);
202
203            status = efi.set_time(&eft);
204
205            spin_unlock_irqrestore(&efi_rtc_lock,flags);
206
207            return status == EFI_SUCCESS ? 0 : -EINVAL;
208
209        case RTC_WKALM_SET:
210
211            if (!capable(CAP_SYS_TIME)) return -EACCES;
212
213            ewp = (struct rtc_wkalrm __user *)arg;
214
215            if ( get_user(enabled, &ewp->enabled)
216               || copy_from_user(&wtime, &ewp->time, sizeof(struct rtc_time)) )
217                return -EFAULT;
218
219            convert_to_efi_time(&wtime, &eft);
220
221            spin_lock_irqsave(&efi_rtc_lock, flags);
222            /*
223             * XXX Fixme:
224             * As of EFI 0.92 with the firmware I have on my
225             * machine this call does not seem to work quite
226             * right
227             */
228            status = efi.set_wakeup_time((efi_bool_t)enabled, &eft);
229
230            spin_unlock_irqrestore(&efi_rtc_lock,flags);
231
232            return status == EFI_SUCCESS ? 0 : -EINVAL;
233
234        case RTC_WKALM_RD:
235
236            spin_lock_irqsave(&efi_rtc_lock, flags);
237
238            status = efi.get_wakeup_time((efi_bool_t *)&enabled, (efi_bool_t *)&pending, &eft);
239
240            spin_unlock_irqrestore(&efi_rtc_lock,flags);
241
242            if (status != EFI_SUCCESS) return -EINVAL;
243
244            ewp = (struct rtc_wkalrm __user *)arg;
245
246            if ( put_user(enabled, &ewp->enabled)
247               || put_user(pending, &ewp->pending)) return -EFAULT;
248
249            convert_from_efi_time(&eft, &wtime);
250
251            return copy_to_user(&ewp->time, &wtime,
252                        sizeof(struct rtc_time)) ? -EFAULT : 0;
253    }
254    return -ENOTTY;
255}
256
257/*
258 * We enforce only one user at a time here with the open/close.
259 * Also clear the previous interrupt data on an open, and clean
260 * up things on a close.
261 */
262
263static int efi_rtc_open(struct inode *inode, struct file *file)
264{
265    /*
266     * nothing special to do here
267     * We do accept multiple open files at the same time as we
268     * synchronize on the per call operation.
269     */
270    return 0;
271}
272
273static int efi_rtc_close(struct inode *inode, struct file *file)
274{
275    return 0;
276}
277
278/*
279 * The various file operations we support.
280 */
281
282static const struct file_operations efi_rtc_fops = {
283    .owner = THIS_MODULE,
284    .unlocked_ioctl = efi_rtc_ioctl,
285    .open = efi_rtc_open,
286    .release = efi_rtc_close,
287    .llseek = no_llseek,
288};
289
290static struct miscdevice efi_rtc_dev= {
291    EFI_RTC_MINOR,
292    "efirtc",
293    &efi_rtc_fops
294};
295
296/*
297 * We export RAW EFI information to /proc/driver/efirtc
298 */
299static int
300efi_rtc_get_status(char *buf)
301{
302    efi_time_t eft, alm;
303    efi_time_cap_t cap;
304    char *p = buf;
305    efi_bool_t enabled, pending;
306    unsigned long flags;
307
308    memset(&eft, 0, sizeof(eft));
309    memset(&alm, 0, sizeof(alm));
310    memset(&cap, 0, sizeof(cap));
311
312    spin_lock_irqsave(&efi_rtc_lock, flags);
313
314    efi.get_time(&eft, &cap);
315    efi.get_wakeup_time(&enabled, &pending, &alm);
316
317    spin_unlock_irqrestore(&efi_rtc_lock,flags);
318
319    p += sprintf(p,
320             "Time : %u:%u:%u.%09u\n"
321             "Date : %u-%u-%u\n"
322             "Daylight : %u\n",
323             eft.hour, eft.minute, eft.second, eft.nanosecond,
324             eft.year, eft.month, eft.day,
325             eft.daylight);
326
327    if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
328        p += sprintf(p, "Timezone : unspecified\n");
329    else
330        /* XXX fixme: convert to string? */
331        p += sprintf(p, "Timezone : %u\n", eft.timezone);
332        
333
334    p += sprintf(p,
335             "Alarm Time : %u:%u:%u.%09u\n"
336             "Alarm Date : %u-%u-%u\n"
337             "Alarm Daylight : %u\n"
338             "Enabled : %s\n"
339             "Pending : %s\n",
340             alm.hour, alm.minute, alm.second, alm.nanosecond,
341             alm.year, alm.month, alm.day,
342             alm.daylight,
343             enabled == 1 ? "yes" : "no",
344             pending == 1 ? "yes" : "no");
345
346    if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
347        p += sprintf(p, "Timezone : unspecified\n");
348    else
349        /* XXX fixme: convert to string? */
350        p += sprintf(p, "Timezone : %u\n", alm.timezone);
351
352    /*
353     * now prints the capabilities
354     */
355    p += sprintf(p,
356             "Resolution : %u\n"
357             "Accuracy : %u\n"
358             "SetstoZero : %u\n",
359              cap.resolution, cap.accuracy, cap.sets_to_zero);
360
361    return p - buf;
362}
363
364static int
365efi_rtc_read_proc(char *page, char **start, off_t off,
366                                 int count, int *eof, void *data)
367{
368        int len = efi_rtc_get_status(page);
369        if (len <= off+count) *eof = 1;
370        *start = page + off;
371        len -= off;
372        if (len>count) len = count;
373        if (len<0) len = 0;
374        return len;
375}
376
377static int __init
378efi_rtc_init(void)
379{
380    int ret;
381    struct proc_dir_entry *dir;
382
383    printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);
384
385    ret = misc_register(&efi_rtc_dev);
386    if (ret) {
387        printk(KERN_ERR "efirtc: can't misc_register on minor=%d\n",
388                EFI_RTC_MINOR);
389        return ret;
390    }
391
392    dir = create_proc_read_entry ("driver/efirtc", 0, NULL,
393                          efi_rtc_read_proc, NULL);
394    if (dir == NULL) {
395        printk(KERN_ERR "efirtc: can't create /proc/driver/efirtc.\n");
396        misc_deregister(&efi_rtc_dev);
397        return -1;
398    }
399    return 0;
400}
401
402static void __exit
403efi_rtc_exit(void)
404{
405    /* not yet used */
406}
407
408module_init(efi_rtc_init);
409module_exit(efi_rtc_exit);
410
411MODULE_LICENSE("GPL");
412

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