/arch/ppc64/kernel/rtc.c

  1/*
  2 *	Real Time Clock interface for PPC64.
  3 *
  4 *	Based on rtc.c by Paul Gortmaker
  5 *
  6 *	This driver allows use of the real time clock
  7 *	from user space. It exports the /dev/rtc
  8 *	interface supporting various ioctl() and also the
  9 *	/proc/driver/rtc pseudo-file for status information.
 10 *
 11 * 	Interface does not support RTC interrupts nor an alarm.
 12 *
 13 *	This program is free software; you can redistribute it and/or
 14 *	modify it under the terms of the GNU General Public License
 15 *	as published by the Free Software Foundation; either version
 16 *	2 of the License, or (at your option) any later version.
 17 *
 18 *      1.0	Mike Corrigan:    IBM iSeries rtc support
 19 *      1.1	Dave Engebretsen: IBM pSeries rtc support
 20 */
 21
 22#define RTC_VERSION		"1.1"
 23
 24#include <linux/config.h>
 25#include <linux/module.h>
 26#include <linux/kernel.h>
 27#include <linux/types.h>
 28#include <linux/miscdevice.h>
 29#include <linux/ioport.h>
 30#include <linux/fcntl.h>
 31#include <linux/mc146818rtc.h>
 32#include <linux/init.h>
 33#include <linux/poll.h>
 34#include <linux/proc_fs.h>
 35#include <linux/spinlock.h>
 36#include <linux/bcd.h>
 37#include <linux/interrupt.h>
 38
 39#include <asm/io.h>
 40#include <asm/uaccess.h>
 41#include <asm/system.h>
 42#include <asm/time.h>
 43#include <asm/rtas.h>
 44
 45#include <asm/iSeries/LparData.h>
 46#include <asm/iSeries/mf.h>
 47#include <asm/machdep.h>
 48#include <asm/iSeries/ItSpCommArea.h>
 49
 50extern int piranha_simulator;
 51
 52/*
 53 *	We sponge a minor off of the misc major. No need slurping
 54 *	up another valuable major dev number for this. If you add
 55 *	an ioctl, make sure you don't conflict with SPARC's RTC
 56 *	ioctls.
 57 */
 58
 59static ssize_t rtc_read(struct file *file, char __user *buf,
 60			size_t count, loff_t *ppos);
 61
 62static int rtc_ioctl(struct inode *inode, struct file *file,
 63		     unsigned int cmd, unsigned long arg);
 64
 65static int rtc_read_proc(char *page, char **start, off_t off,
 66                         int count, int *eof, void *data);
 67
 68/*
 69 *	If this driver ever becomes modularised, it will be really nice
 70 *	to make the epoch retain its value across module reload...
 71 */
 72
 73static unsigned long epoch = 1900;	/* year corresponding to 0x00	*/
 74
 75static const unsigned char days_in_mo[] = 
 76{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 77
 78/*
 79 *	Now all the various file operations that we export.
 80 */
 81
 82static ssize_t rtc_read(struct file *file, char __user *buf,
 83			size_t count, loff_t *ppos)
 84{
 85	return -EIO;
 86}
 87
 88static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 89		     unsigned long arg)
 90{
 91	struct rtc_time wtime; 
 92
 93	switch (cmd) {
 94	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
 95	{
 96		memset(&wtime, 0, sizeof(struct rtc_time));
 97		ppc_md.get_rtc_time(&wtime);
 98		break;
 99	}
100	case RTC_SET_TIME:	/* Set the RTC */
101	{
102		struct rtc_time rtc_tm;
103		unsigned char mon, day, hrs, min, sec, leap_yr;
104		unsigned int yrs;
105
106		if (!capable(CAP_SYS_TIME))
107			return -EACCES;
108
109		if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
110				   sizeof(struct rtc_time)))
111			return -EFAULT;
112
113		yrs = rtc_tm.tm_year;
114		mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
115		day = rtc_tm.tm_mday;
116		hrs = rtc_tm.tm_hour;
117		min = rtc_tm.tm_min;
118		sec = rtc_tm.tm_sec;
119
120		if (yrs < 70)
121			return -EINVAL;
122
123		leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
124
125		if ((mon > 12) || (day == 0))
126			return -EINVAL;
127
128		if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
129			return -EINVAL;
130			
131		if ((hrs >= 24) || (min >= 60) || (sec >= 60))
132			return -EINVAL;
133
134		if ( yrs > 169 )
135			return -EINVAL;
136
137		ppc_md.set_rtc_time(&rtc_tm);
138		
139		return 0;
140	}
141	case RTC_EPOCH_READ:	/* Read the epoch.	*/
142	{
143		return put_user (epoch, (unsigned long __user *)arg);
144	}
145	case RTC_EPOCH_SET:	/* Set the epoch.	*/
146	{
147		/* 
148		 * There were no RTC clocks before 1900.
149		 */
150		if (arg < 1900)
151			return -EINVAL;
152
153		if (!capable(CAP_SYS_TIME))
154			return -EACCES;
155
156		epoch = arg;
157		return 0;
158	}
159	default:
160		return -EINVAL;
161	}
162	return copy_to_user((void __user *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
163}
164
165static int rtc_open(struct inode *inode, struct file *file)
166{
167	nonseekable_open(inode, file);
168	return 0;
169}
170
171static int rtc_release(struct inode *inode, struct file *file)
172{
173	return 0;
174}
175
176/*
177 *	The various file operations we support.
178 */
179static struct file_operations rtc_fops = {
180	.owner =	THIS_MODULE,
181	.llseek =	no_llseek,
182	.read =		rtc_read,
183	.ioctl =	rtc_ioctl,
184	.open =		rtc_open,
185	.release =	rtc_release,
186};
187
188static struct miscdevice rtc_dev = {
189	.minor =	RTC_MINOR,
190	.name =		"rtc",
191	.fops =		&rtc_fops
192};
193
194static int __init rtc_init(void)
195{
196	int retval;
197
198	retval = misc_register(&rtc_dev);
199	if(retval < 0)
200		return retval;
201
202#ifdef CONFIG_PROC_FS
203	if (create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)
204			== NULL) {
205		misc_deregister(&rtc_dev);
206		return -ENOMEM;
207	}
208#endif
209
210	printk(KERN_INFO "i/pSeries Real Time Clock Driver v" RTC_VERSION "\n");
211
212	return 0;
213}
214
215static void __exit rtc_exit (void)
216{
217	remove_proc_entry ("driver/rtc", NULL);
218	misc_deregister(&rtc_dev);
219}
220
221module_init(rtc_init);
222module_exit(rtc_exit);
223
224/*
225 *	Info exported via "/proc/driver/rtc".
226 */
227
228static int rtc_proc_output (char *buf)
229{
230	
231	char *p;
232	struct rtc_time tm;
233	
234	p = buf;
235
236	ppc_md.get_rtc_time(&tm);
237
238	/*
239	 * There is no way to tell if the luser has the RTC set for local
240	 * time or for Universal Standard Time (GMT). Probably local though.
241	 */
242	p += sprintf(p,
243		     "rtc_time\t: %02d:%02d:%02d\n"
244		     "rtc_date\t: %04d-%02d-%02d\n"
245	 	     "rtc_epoch\t: %04lu\n",
246		     tm.tm_hour, tm.tm_min, tm.tm_sec,
247		     tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
248
249	p += sprintf(p,
250		     "DST_enable\t: no\n"
251		     "BCD\t\t: yes\n"
252		     "24hr\t\t: yes\n" );
253
254	return  p - buf;
255}
256
257static int rtc_read_proc(char *page, char **start, off_t off,
258                         int count, int *eof, void *data)
259{
260        int len = rtc_proc_output (page);
261        if (len <= off+count) *eof = 1;
262        *start = page + off;
263        len -= off;
264        if (len>count) len = count;
265        if (len<0) len = 0;
266        return len;
267}
268
269#ifdef CONFIG_PPC_ISERIES
270/*
271 * Get the RTC from the virtual service processor
272 * This requires flowing LpEvents to the primary partition
273 */
274void iSeries_get_rtc_time(struct rtc_time *rtc_tm)
275{
276	if (piranha_simulator)
277		return;
278
279	mf_get_rtc(rtc_tm);
280	rtc_tm->tm_mon--;
281}
282
283/*
284 * Set the RTC in the virtual service processor
285 * This requires flowing LpEvents to the primary partition
286 */
287int iSeries_set_rtc_time(struct rtc_time *tm)
288{
289	mf_set_rtc(tm);
290	return 0;
291}
292
293void iSeries_get_boot_time(struct rtc_time *tm)
294{
295	unsigned long time;
296	static unsigned long lastsec = 1;
297
298	u32 dataWord1 = *((u32 *)(&xSpCommArea.xBcdTimeAtIplStart));
299	u32 dataWord2 = *(((u32 *)&(xSpCommArea.xBcdTimeAtIplStart)) + 1);
300	int year = 1970;
301	int year1 = ( dataWord1 >> 24 ) & 0x000000FF;
302	int year2 = ( dataWord1 >> 16 ) & 0x000000FF;
303	int sec = ( dataWord1 >> 8 ) & 0x000000FF;
304	int min = dataWord1 & 0x000000FF;
305	int hour = ( dataWord2 >> 24 ) & 0x000000FF;
306	int day = ( dataWord2 >> 8 ) & 0x000000FF;
307	int mon = dataWord2 & 0x000000FF;
308
309	if ( piranha_simulator )
310		return;
311
312	BCD_TO_BIN(sec);
313	BCD_TO_BIN(min);
314	BCD_TO_BIN(hour);
315	BCD_TO_BIN(day);
316	BCD_TO_BIN(mon);
317	BCD_TO_BIN(year1);
318	BCD_TO_BIN(year2);
319	year = year1 * 100 + year2;
320
321	time = mktime(year, mon, day, hour, min, sec);
322	time += ( jiffies / HZ );
323
324	/* Now THIS is a nasty hack!
325	* It ensures that the first two calls get different answers.  
326	* That way the loop in init_time (time.c) will not think
327	* the clock is stuck.
328	*/
329	if ( lastsec ) {
330		time -= lastsec;
331		--lastsec;
332	}
333
334	to_tm(time, tm); 
335	tm->tm_year -= 1900;
336	tm->tm_mon  -= 1;
337}
338#endif
339
340#ifdef CONFIG_PPC_RTAS
341#define MAX_RTC_WAIT 5000	/* 5 sec */
342#define RTAS_CLOCK_BUSY (-2)
343void pSeries_get_boot_time(struct rtc_time *rtc_tm)
344{
345	int ret[8];
346	int error, wait_time;
347	unsigned long max_wait_tb;
348
349	max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
350	do {
351		error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
352		if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
353			wait_time = rtas_extended_busy_delay_time(error);
354			/* This is boot time so we spin. */
355			udelay(wait_time*1000);
356			error = RTAS_CLOCK_BUSY;
357		}
358	} while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
359
360	if (error != 0 && printk_ratelimit()) {
361		printk(KERN_WARNING "error: reading the clock failed (%d)\n",
362			error);
363		return;
364	}
365
366	rtc_tm->tm_sec = ret[5];
367	rtc_tm->tm_min = ret[4];
368	rtc_tm->tm_hour = ret[3];
369	rtc_tm->tm_mday = ret[2];
370	rtc_tm->tm_mon = ret[1] - 1;
371	rtc_tm->tm_year = ret[0] - 1900;
372}
373
374/* NOTE: get_rtc_time will get an error if executed in interrupt context
375 * and if a delay is needed to read the clock.  In this case we just
376 * silently return without updating rtc_tm.
377 */
378void pSeries_get_rtc_time(struct rtc_time *rtc_tm)
379{
380        int ret[8];
381	int error, wait_time;
382	unsigned long max_wait_tb;
383
384	max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
385	do {
386		error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
387		if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
388			if (in_interrupt() && printk_ratelimit()) {
389				printk(KERN_WARNING "error: reading clock would delay interrupt\n");
390				return;	/* delay not allowed */
391			}
392			wait_time = rtas_extended_busy_delay_time(error);
393			set_current_state(TASK_INTERRUPTIBLE);
394			schedule_timeout(wait_time);
395			error = RTAS_CLOCK_BUSY;
396		}
397	} while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
398
399        if (error != 0 && printk_ratelimit()) {
400                printk(KERN_WARNING "error: reading the clock failed (%d)\n",
401		       error);
402		return;
403        }
404
405	rtc_tm->tm_sec = ret[5];
406	rtc_tm->tm_min = ret[4];
407	rtc_tm->tm_hour = ret[3];
408	rtc_tm->tm_mday = ret[2];
409	rtc_tm->tm_mon = ret[1] - 1;
410	rtc_tm->tm_year = ret[0] - 1900;
411}
412
413int pSeries_set_rtc_time(struct rtc_time *tm)
414{
415	int error, wait_time;
416	unsigned long max_wait_tb;
417
418	max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
419	do {
420	        error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
421				  tm->tm_year + 1900, tm->tm_mon + 1, 
422				  tm->tm_mday, tm->tm_hour, tm->tm_min, 
423				  tm->tm_sec, 0);
424		if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
425			if (in_interrupt())
426				return 1;	/* probably decrementer */
427			wait_time = rtas_extended_busy_delay_time(error);
428			set_current_state(TASK_INTERRUPTIBLE);
429			schedule_timeout(wait_time);
430			error = RTAS_CLOCK_BUSY;
431		}
432	} while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
433
434        if (error != 0 && printk_ratelimit())
435                printk(KERN_WARNING "error: setting the clock failed (%d)\n",
436		       error); 
437
438        return 0;
439}
440#endif