arch/m68k/atari/time.c

   1 /*
   2  * linux/arch/m68k/atari/time.c
   3  *
   4  * Atari time and real time clock stuff
   5  *
   6  * Assembled of parts of former atari/config.c 97-12-18 by Roman Hodek
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file COPYING in the main directory of this archive
  10  * for more details.
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/mc146818rtc.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/init.h>
  17 #include <linux/rtc.h>
  18 #include <linux/bcd.h>
  19 #include <linux/clocksource.h>
  20 #include <linux/delay.h>
  21 #include <linux/export.h>
  22
  23 #include <asm/atariints.h>
  24 #include <asm/machdep.h>
  25
  26 DEFINE_SPINLOCK(rtc_lock);
  27 EXPORT_SYMBOL_GPL(rtc_lock);
  28
  29 static u64 atari_read_clk(struct clocksource *cs);
  30
  31 static struct clocksource atari_clk = {
  32         .name   = "mfp",
  33         .rating = 100,
  34         .read   = atari_read_clk,
  35         .mask   = CLOCKSOURCE_MASK(32),
  36         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
  37 };
  38
  39 static u32 clk_total;
  40 static u8 last_timer_count;
  41
  42 static irqreturn_t mfp_timer_c_handler(int irq, void *dev_id)
  43 {
  44         unsigned long flags;
  45
  46         local_irq_save(flags);
  47         do {
  48                 last_timer_count = st_mfp.tim_dt_c;
  49         } while (last_timer_count == 1);
  50         clk_total += INT_TICKS;
  51         legacy_timer_tick(1);
  52         timer_heartbeat();
  53         local_irq_restore(flags);
  54
  55         return IRQ_HANDLED;
  56 }
  57
  58 void __init
  59 atari_sched_init(void)
  60 {
  61     /* set Timer C data Register */
  62     st_mfp.tim_dt_c = INT_TICKS;
  63     /* start timer C, div = 1:100 */
  64     st_mfp.tim_ct_cd = (st_mfp.tim_ct_cd & 15) | 0x60;
  65     /* install interrupt service routine for MFP Timer C */
  66     if (request_irq(IRQ_MFP_TIMC, mfp_timer_c_handler, IRQF_TIMER, "timer",
  67                     NULL))
  68         pr_err("Couldn't register timer interrupt\n");
  69
  70     clocksource_register_hz(&atari_clk, INT_CLK);
  71 }
  72
  73 /* ++andreas: gettimeoffset fixed to check for pending interrupt */
  74
  75 static u64 atari_read_clk(struct clocksource *cs)
  76 {
  77         unsigned long flags;
  78         u8 count;
  79         u32 ticks;
  80
  81         local_irq_save(flags);
  82         /* Ensure that the count is monotonically decreasing, even though
  83          * the result may briefly stop changing after counter wrap-around.
  84          */
  85         count = min(st_mfp.tim_dt_c, last_timer_count);
  86         last_timer_count = count;
  87
  88         ticks = INT_TICKS - count;
  89         ticks += clk_total;
  90         local_irq_restore(flags);
  91
  92         return ticks;
  93 }
  94
  95
  96 static void mste_read(struct MSTE_RTC *val)
  97 {
  98 #define COPY(v) val->v=(mste_rtc.v & 0xf)
  99         do {
 100                 COPY(sec_ones) ; COPY(sec_tens) ; COPY(min_ones) ;
 101                 COPY(min_tens) ; COPY(hr_ones) ; COPY(hr_tens) ;
 102                 COPY(weekday) ; COPY(day_ones) ; COPY(day_tens) ;
 103                 COPY(mon_ones) ; COPY(mon_tens) ; COPY(year_ones) ;
 104                 COPY(year_tens) ;
 105         /* prevent from reading the clock while it changed */
 106         } while (val->sec_ones != (mste_rtc.sec_ones & 0xf));
 107 #undef COPY
 108 }
 109
 110 static void mste_write(struct MSTE_RTC *val)
 111 {
 112 #define COPY(v) mste_rtc.v=val->v
 113         do {
 114                 COPY(sec_ones) ; COPY(sec_tens) ; COPY(min_ones) ;
 115                 COPY(min_tens) ; COPY(hr_ones) ; COPY(hr_tens) ;
 116                 COPY(weekday) ; COPY(day_ones) ; COPY(day_tens) ;
 117                 COPY(mon_ones) ; COPY(mon_tens) ; COPY(year_ones) ;
 118                 COPY(year_tens) ;
 119         /* prevent from writing the clock while it changed */
 120         } while (val->sec_ones != (mste_rtc.sec_ones & 0xf));
 121 #undef COPY
 122 }
 123
 124 #define RTC_READ(reg)                           \
 125     ({  unsigned char   __val;                  \
 126                 (void) atari_writeb(reg,&tt_rtc.regsel);        \
 127                 __val = tt_rtc.data;            \
 128                 __val;                          \
 129         })
 130
 131 #define RTC_WRITE(reg,val)                      \
 132     do {                                        \
 133                 atari_writeb(reg,&tt_rtc.regsel);       \
 134                 tt_rtc.data = (val);            \
 135         } while(0)
 136
 137
 138 #define HWCLK_POLL_INTERVAL     5
 139
 140 int atari_mste_hwclk( int op, struct rtc_time *t )
 141 {
 142     int hour, year;
 143     int hr24=0;
 144     struct MSTE_RTC val;
 145
 146     mste_rtc.mode=(mste_rtc.mode | 1);
 147     hr24=mste_rtc.mon_tens & 1;
 148     mste_rtc.mode=(mste_rtc.mode & ~1);
 149
 150     if (op) {
 151         /* write: prepare values */
 152
 153         val.sec_ones = t->tm_sec % 10;
 154         val.sec_tens = t->tm_sec / 10;
 155         val.min_ones = t->tm_min % 10;
 156         val.min_tens = t->tm_min / 10;
 157         hour = t->tm_hour;
 158         if (!hr24) {
 159             if (hour > 11)
 160                 hour += 20 - 12;
 161             if (hour == 0 || hour == 20)
 162                 hour += 12;
 163         }
 164         val.hr_ones = hour % 10;
 165         val.hr_tens = hour / 10;
 166         val.day_ones = t->tm_mday % 10;
 167         val.day_tens = t->tm_mday / 10;
 168         val.mon_ones = (t->tm_mon+1) % 10;
 169         val.mon_tens = (t->tm_mon+1) / 10;
 170         year = t->tm_year - 80;
 171         val.year_ones = year % 10;
 172         val.year_tens = year / 10;
 173         val.weekday = t->tm_wday;
 174         mste_write(&val);
 175         mste_rtc.mode=(mste_rtc.mode | 1);
 176         val.year_ones = (year % 4);     /* leap year register */
 177         mste_rtc.mode=(mste_rtc.mode & ~1);
 178     }
 179     else {
 180         mste_read(&val);
 181         t->tm_sec = val.sec_ones + val.sec_tens * 10;
 182         t->tm_min = val.min_ones + val.min_tens * 10;
 183         hour = val.hr_ones + val.hr_tens * 10;
 184         if (!hr24) {
 185             if (hour == 12 || hour == 12 + 20)
 186                 hour -= 12;
 187             if (hour >= 20)
 188                 hour += 12 - 20;
 189         }
 190         t->tm_hour = hour;
 191         t->tm_mday = val.day_ones + val.day_tens * 10;
 192         t->tm_mon  = val.mon_ones + val.mon_tens * 10 - 1;
 193         t->tm_year = val.year_ones + val.year_tens * 10 + 80;
 194         t->tm_wday = val.weekday;
 195     }
 196     return 0;
 197 }
 198
 199 int atari_tt_hwclk( int op, struct rtc_time *t )
 200 {
 201     int sec=0, min=0, hour=0, day=0, mon=0, year=0, wday=0;
 202     unsigned long       flags;
 203     unsigned char       ctrl;
 204     int pm = 0;
 205
 206     ctrl = RTC_READ(RTC_CONTROL); /* control registers are
 207                                    * independent from the UIP */
 208
 209     if (op) {
 210         /* write: prepare values */
 211
 212         sec  = t->tm_sec;
 213         min  = t->tm_min;
 214         hour = t->tm_hour;
 215         day  = t->tm_mday;
 216         mon  = t->tm_mon + 1;
 217         year = t->tm_year - atari_rtc_year_offset;
 218         wday = t->tm_wday + (t->tm_wday >= 0);
 219
 220         if (!(ctrl & RTC_24H)) {
 221             if (hour > 11) {
 222                 pm = 0x80;
 223                 if (hour != 12)
 224                     hour -= 12;
 225             }
 226             else if (hour == 0)
 227                 hour = 12;
 228         }
 229
 230         if (!(ctrl & RTC_DM_BINARY)) {
 231             sec = bin2bcd(sec);
 232             min = bin2bcd(min);
 233             hour = bin2bcd(hour);
 234             day = bin2bcd(day);
 235             mon = bin2bcd(mon);
 236             year = bin2bcd(year);
 237             if (wday >= 0)
 238                 wday = bin2bcd(wday);
 239         }
 240     }
 241
 242     /* Reading/writing the clock registers is a bit critical due to
 243      * the regular update cycle of the RTC. While an update is in
 244      * progress, registers 0..9 shouldn't be touched.
 245      * The problem is solved like that: If an update is currently in
 246      * progress (the UIP bit is set), the process sleeps for a while
 247      * (50ms). This really should be enough, since the update cycle
 248      * normally needs 2 ms.
 249      * If the UIP bit reads as 0, we have at least 244 usecs until the
 250      * update starts. This should be enough... But to be sure,
 251      * additionally the RTC_SET bit is set to prevent an update cycle.
 252      */
 253
 254     while( RTC_READ(RTC_FREQ_SELECT) & RTC_UIP ) {
 255         if (in_atomic() || irqs_disabled())
 256             mdelay(1);
 257         else
 258             schedule_timeout_interruptible(HWCLK_POLL_INTERVAL);
 259     }
 260
 261     local_irq_save(flags);
 262     RTC_WRITE( RTC_CONTROL, ctrl | RTC_SET );
 263     if (!op) {
 264         sec  = RTC_READ( RTC_SECONDS );
 265         min  = RTC_READ( RTC_MINUTES );
 266         hour = RTC_READ( RTC_HOURS );
 267         day  = RTC_READ( RTC_DAY_OF_MONTH );
 268         mon  = RTC_READ( RTC_MONTH );
 269         year = RTC_READ( RTC_YEAR );
 270         wday = RTC_READ( RTC_DAY_OF_WEEK );
 271     }
 272     else {
 273         RTC_WRITE( RTC_SECONDS, sec );
 274         RTC_WRITE( RTC_MINUTES, min );
 275         RTC_WRITE( RTC_HOURS, hour + pm);
 276         RTC_WRITE( RTC_DAY_OF_MONTH, day );
 277         RTC_WRITE( RTC_MONTH, mon );
 278         RTC_WRITE( RTC_YEAR, year );
 279         if (wday >= 0) RTC_WRITE( RTC_DAY_OF_WEEK, wday );
 280     }
 281     RTC_WRITE( RTC_CONTROL, ctrl & ~RTC_SET );
 282     local_irq_restore(flags);
 283
 284     if (!op) {
 285         /* read: adjust values */
 286
 287         if (hour & 0x80) {
 288             hour &= ~0x80;
 289             pm = 1;
 290         }
 291
 292         if (!(ctrl & RTC_DM_BINARY)) {
 293             sec = bcd2bin(sec);
 294             min = bcd2bin(min);
 295             hour = bcd2bin(hour);
 296             day = bcd2bin(day);
 297             mon = bcd2bin(mon);
 298             year = bcd2bin(year);
 299             wday = bcd2bin(wday);
 300         }
 301
 302         if (!(ctrl & RTC_24H)) {
 303             if (!pm && hour == 12)
 304                 hour = 0;
 305             else if (pm && hour != 12)
 306                 hour += 12;
 307         }
 308
 309         t->tm_sec  = sec;
 310         t->tm_min  = min;
 311         t->tm_hour = hour;
 312         t->tm_mday = day;
 313         t->tm_mon  = mon - 1;
 314         t->tm_year = year + atari_rtc_year_offset;
 315         t->tm_wday = wday - 1;
 316     }
 317
 318     return( 0 );
 319 }
 320
 321 /*
 322  * Local variables:
 323  *  c-indent-level: 4
 324  *  tab-width: 8
 325  * End:
 326  */