ia64/linux-2.6.18-xen.hg

view drivers/char/ds1302.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
1 /*!***************************************************************************
2 *!
3 *! FILE NAME : ds1302.c
4 *!
5 *! DESCRIPTION: Implements an interface for the DS1302 RTC
6 *!
7 *! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init, get_rtc_status
8 *!
9 *! ---------------------------------------------------------------------------
10 *!
11 *! (C) Copyright 1999, 2000, 2001 Axis Communications AB, LUND, SWEDEN
12 *!
13 *!***************************************************************************/
16 #include <linux/fs.h>
17 #include <linux/init.h>
18 #include <linux/mm.h>
19 #include <linux/module.h>
20 #include <linux/miscdevice.h>
21 #include <linux/delay.h>
22 #include <linux/bcd.h>
24 #include <asm/uaccess.h>
25 #include <asm/system.h>
26 #include <asm/io.h>
27 #include <asm/rtc.h>
28 #if defined(CONFIG_M32R)
29 #include <asm/m32r.h>
30 #endif
32 #define RTC_MAJOR_NR 121 /* local major, change later */
34 static const char ds1302_name[] = "ds1302";
36 /* Send 8 bits. */
37 static void
38 out_byte_rtc(unsigned int reg_addr, unsigned char x)
39 {
40 //RST H
41 outw(0x0001,(unsigned long)PLD_RTCRSTODT);
42 //write data
43 outw(((x<<8)|(reg_addr&0xff)),(unsigned long)PLD_RTCWRDATA);
44 //WE
45 outw(0x0002,(unsigned long)PLD_RTCCR);
46 //wait
47 while(inw((unsigned long)PLD_RTCCR));
49 //RST L
50 outw(0x0000,(unsigned long)PLD_RTCRSTODT);
52 }
54 static unsigned char
55 in_byte_rtc(unsigned int reg_addr)
56 {
57 unsigned char retval;
59 //RST H
60 outw(0x0001,(unsigned long)PLD_RTCRSTODT);
61 //write data
62 outw((reg_addr&0xff),(unsigned long)PLD_RTCRDDATA);
63 //RE
64 outw(0x0001,(unsigned long)PLD_RTCCR);
65 //wait
66 while(inw((unsigned long)PLD_RTCCR));
68 //read data
69 retval=(inw((unsigned long)PLD_RTCRDDATA) & 0xff00)>>8;
71 //RST L
72 outw(0x0000,(unsigned long)PLD_RTCRSTODT);
74 return retval;
75 }
77 /* Enable writing. */
79 static void
80 ds1302_wenable(void)
81 {
82 out_byte_rtc(0x8e,0x00);
83 }
85 /* Disable writing. */
87 static void
88 ds1302_wdisable(void)
89 {
90 out_byte_rtc(0x8e,0x80);
91 }
95 /* Read a byte from the selected register in the DS1302. */
97 unsigned char
98 ds1302_readreg(int reg)
99 {
100 unsigned char x;
102 x=in_byte_rtc((0x81 | (reg << 1))); /* read register */
104 return x;
105 }
107 /* Write a byte to the selected register. */
109 void
110 ds1302_writereg(int reg, unsigned char val)
111 {
112 ds1302_wenable();
113 out_byte_rtc((0x80 | (reg << 1)),val);
114 ds1302_wdisable();
115 }
117 void
118 get_rtc_time(struct rtc_time *rtc_tm)
119 {
120 unsigned long flags;
122 local_irq_save(flags);
123 local_irq_disable();
125 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
126 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
127 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
128 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
129 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
130 rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
132 local_irq_restore(flags);
134 BCD_TO_BIN(rtc_tm->tm_sec);
135 BCD_TO_BIN(rtc_tm->tm_min);
136 BCD_TO_BIN(rtc_tm->tm_hour);
137 BCD_TO_BIN(rtc_tm->tm_mday);
138 BCD_TO_BIN(rtc_tm->tm_mon);
139 BCD_TO_BIN(rtc_tm->tm_year);
141 /*
142 * Account for differences between how the RTC uses the values
143 * and how they are defined in a struct rtc_time;
144 */
146 if (rtc_tm->tm_year <= 69)
147 rtc_tm->tm_year += 100;
149 rtc_tm->tm_mon--;
150 }
152 static unsigned char days_in_mo[] =
153 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
155 /* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
157 static int
158 rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
159 unsigned long arg)
160 {
161 unsigned long flags;
163 switch(cmd) {
164 case RTC_RD_TIME: /* read the time/date from RTC */
165 {
166 struct rtc_time rtc_tm;
168 memset(&rtc_tm, 0, sizeof (struct rtc_time));
169 get_rtc_time(&rtc_tm);
170 if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
171 return -EFAULT;
172 return 0;
173 }
175 case RTC_SET_TIME: /* set the RTC */
176 {
177 struct rtc_time rtc_tm;
178 unsigned char mon, day, hrs, min, sec, leap_yr;
179 unsigned int yrs;
181 if (!capable(CAP_SYS_TIME))
182 return -EPERM;
184 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
185 return -EFAULT;
187 yrs = rtc_tm.tm_year + 1900;
188 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
189 day = rtc_tm.tm_mday;
190 hrs = rtc_tm.tm_hour;
191 min = rtc_tm.tm_min;
192 sec = rtc_tm.tm_sec;
195 if ((yrs < 1970) || (yrs > 2069))
196 return -EINVAL;
198 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
200 if ((mon > 12) || (day == 0))
201 return -EINVAL;
203 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
204 return -EINVAL;
206 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
207 return -EINVAL;
209 if (yrs >= 2000)
210 yrs -= 2000; /* RTC (0, 1, ... 69) */
211 else
212 yrs -= 1900; /* RTC (70, 71, ... 99) */
214 BIN_TO_BCD(sec);
215 BIN_TO_BCD(min);
216 BIN_TO_BCD(hrs);
217 BIN_TO_BCD(day);
218 BIN_TO_BCD(mon);
219 BIN_TO_BCD(yrs);
221 local_irq_save(flags);
222 local_irq_disable();
223 CMOS_WRITE(yrs, RTC_YEAR);
224 CMOS_WRITE(mon, RTC_MONTH);
225 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
226 CMOS_WRITE(hrs, RTC_HOURS);
227 CMOS_WRITE(min, RTC_MINUTES);
228 CMOS_WRITE(sec, RTC_SECONDS);
229 local_irq_restore(flags);
231 /* Notice that at this point, the RTC is updated but
232 * the kernel is still running with the old time.
233 * You need to set that separately with settimeofday
234 * or adjtimex.
235 */
236 return 0;
237 }
239 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
240 {
241 int tcs_val;
243 if (!capable(CAP_SYS_TIME))
244 return -EPERM;
246 if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
247 return -EFAULT;
249 tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
250 ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
251 return 0;
252 }
253 default:
254 return -EINVAL;
255 }
256 }
258 int
259 get_rtc_status(char *buf)
260 {
261 char *p;
262 struct rtc_time tm;
264 p = buf;
266 get_rtc_time(&tm);
268 /*
269 * There is no way to tell if the luser has the RTC set for local
270 * time or for Universal Standard Time (GMT). Probably local though.
271 */
273 p += sprintf(p,
274 "rtc_time\t: %02d:%02d:%02d\n"
275 "rtc_date\t: %04d-%02d-%02d\n",
276 tm.tm_hour, tm.tm_min, tm.tm_sec,
277 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
279 return p - buf;
280 }
283 /* The various file operations we support. */
285 static const struct file_operations rtc_fops = {
286 .owner = THIS_MODULE,
287 .ioctl = rtc_ioctl,
288 };
290 /* Probe for the chip by writing something to its RAM and try reading it back. */
292 #define MAGIC_PATTERN 0x42
294 static int __init
295 ds1302_probe(void)
296 {
297 int retval, res, baur;
299 baur=(boot_cpu_data.bus_clock/(2*1000*1000));
301 printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur);
303 outw(0x0000,(unsigned long)PLD_RTCCR);
304 outw(0x0000,(unsigned long)PLD_RTCRSTODT);
305 outw(baur,(unsigned long)PLD_RTCBAUR);
307 /* Try to talk to timekeeper. */
309 ds1302_wenable();
310 /* write RAM byte 0 */
311 /* write something magic */
312 out_byte_rtc(0xc0,MAGIC_PATTERN);
314 /* read RAM byte 0 */
315 if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) {
316 char buf[100];
317 ds1302_wdisable();
318 printk("%s: RTC found.\n", ds1302_name);
319 get_rtc_status(buf);
320 printk(buf);
321 retval = 1;
322 } else {
323 printk("%s: RTC not found.\n", ds1302_name);
324 retval = 0;
325 }
327 return retval;
328 }
331 /* Just probe for the RTC and register the device to handle the ioctl needed. */
333 int __init
334 ds1302_init(void)
335 {
336 if (!ds1302_probe()) {
337 return -1;
338 }
339 return 0;
340 }
342 static int __init ds1302_register(void)
343 {
344 ds1302_init();
345 if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
346 printk(KERN_INFO "%s: unable to get major %d for rtc\n",
347 ds1302_name, RTC_MAJOR_NR);
348 return -1;
349 }
350 return 0;
351 }
353 module_init(ds1302_register);