arch/powerpc/platforms/powermac/time.c

   1 /*
   2  * Support for periodic interrupts (100 per second) and for getting
   3  * the current time from the RTC on Power Macintoshes.
   4  *
   5  * We use the decrementer register for our periodic interrupts.
   6  *
   7  * Paul Mackerras       August 1996.
   8  * Copyright (C) 1996 Paul Mackerras.
   9  * Copyright (C) 2003-2005 Benjamin Herrenschmidt.
  10  *
  11  */
  12 #include <linux/config.h>
  13 #include <linux/errno.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/param.h>
  17 #include <linux/string.h>
  18 #include <linux/mm.h>
  19 #include <linux/init.h>
  20 #include <linux/time.h>
  21 #include <linux/adb.h>
  22 #include <linux/cuda.h>
  23 #include <linux/pmu.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/hardirq.h>
  26 #include <linux/rtc.h>
  27
  28 #include <asm/sections.h>
  29 #include <asm/prom.h>
  30 #include <asm/system.h>
  31 #include <asm/io.h>
  32 #include <asm/pgtable.h>
  33 #include <asm/machdep.h>
  34 #include <asm/time.h>
  35 #include <asm/nvram.h>
  36
  37 #undef DEBUG
  38
  39 #ifdef DEBUG
  40 #define DBG(x...) printk(x)
  41 #else
  42 #define DBG(x...)
  43 #endif
  44
  45 /* Apparently the RTC stores seconds since 1 Jan 1904 */
  46 #define RTC_OFFSET      2082844800
  47
  48 /*
  49  * Calibrate the decrementer frequency with the VIA timer 1.
  50  */
  51 #define VIA_TIMER_FREQ_6        4700000 /* time 1 frequency * 6 */
  52
  53 /* VIA registers */
  54 #define RS              0x200           /* skip between registers */
  55 #define T1CL            (4*RS)          /* Timer 1 ctr/latch (low 8 bits) */
  56 #define T1CH            (5*RS)          /* Timer 1 counter (high 8 bits) */
  57 #define T1LL            (6*RS)          /* Timer 1 latch (low 8 bits) */
  58 #define T1LH            (7*RS)          /* Timer 1 latch (high 8 bits) */
  59 #define ACR             (11*RS)         /* Auxiliary control register */
  60 #define IFR             (13*RS)         /* Interrupt flag register */
  61
  62 /* Bits in ACR */
  63 #define T1MODE          0xc0            /* Timer 1 mode */
  64 #define T1MODE_CONT     0x40            /*  continuous interrupts */
  65
  66 /* Bits in IFR and IER */
  67 #define T1_INT          0x40            /* Timer 1 interrupt */
  68
  69 long __init pmac_time_init(void)
  70 {
  71 #ifdef CONFIG_NVRAM
  72         s32 delta = 0;
  73         int dst;
  74
  75         delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16;
  76         delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8;
  77         delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb);
  78         if (delta & 0x00800000UL)
  79                 delta |= 0xFF000000UL;
  80         dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0);
  81         printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60,
  82                 dst ? "on" : "off");
  83         return delta;
  84 #else
  85         return 0;
  86 #endif
  87 }
  88
  89 unsigned long pmac_get_boot_time(void)
  90 {
  91 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
  92         struct adb_request req;
  93         unsigned long now;
  94 #endif
  95
  96         /* Get the time from the RTC */
  97         switch (sys_ctrler) {
  98 #ifdef CONFIG_ADB_CUDA
  99         case SYS_CTRLER_CUDA:
 100                 if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
 101                         return 0;
 102                 while (!req.complete)
 103                         cuda_poll();
 104                 if (req.reply_len != 7)
 105                         printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n",
 106                                req.reply_len);
 107                 now = (req.reply[3] << 24) + (req.reply[4] << 16)
 108                         + (req.reply[5] << 8) + req.reply[6];
 109                 return now - RTC_OFFSET;
 110 #endif /* CONFIG_ADB_CUDA */
 111 #ifdef CONFIG_ADB_PMU
 112         case SYS_CTRLER_PMU:
 113                 if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0)
 114                         return 0;
 115                 while (!req.complete)
 116                         pmu_poll();
 117                 if (req.reply_len != 4)
 118                         printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n",
 119                                req.reply_len);
 120                 now = (req.reply[0] << 24) + (req.reply[1] << 16)
 121                         + (req.reply[2] << 8) + req.reply[3];
 122                 return now - RTC_OFFSET;
 123 #endif /* CONFIG_ADB_PMU */
 124         default: ;
 125         }
 126         return 0;
 127 }
 128
 129 void pmac_get_rtc_time(struct rtc_time *tm)
 130 {
 131         unsigned long now;
 132
 133         now = pmac_get_boot_time();
 134         to_tm(now, tm);
 135         tm->tm_year -= 1900;
 136         tm->tm_mon -= 1;                /* month is 0-based */
 137 }
 138
 139 int pmac_set_rtc_time(struct rtc_time *tm)
 140 {
 141         unsigned long nowtime;
 142 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
 143         struct adb_request req;
 144 #endif
 145
 146         nowtime = mktime(tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
 147                          tm->tm_hour, tm->tm_min, tm->tm_sec);
 148         nowtime += RTC_OFFSET;
 149
 150         switch (sys_ctrler) {
 151 #ifdef CONFIG_ADB_CUDA
 152         case SYS_CTRLER_CUDA:
 153                 if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
 154                                  nowtime >> 24, nowtime >> 16, nowtime >> 8,
 155                                  nowtime) < 0)
 156                         return 0;
 157                 while (!req.complete)
 158                         cuda_poll();
 159                 if ((req.reply_len != 3) && (req.reply_len != 7))
 160                         printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n",
 161                                req.reply_len);
 162                 return 1;
 163 #endif /* CONFIG_ADB_CUDA */
 164 #ifdef CONFIG_ADB_PMU
 165         case SYS_CTRLER_PMU:
 166                 if (pmu_request(&req, NULL, 5, PMU_SET_RTC,
 167                                 nowtime >> 24, nowtime >> 16, nowtime >> 8, nowtime) < 0)
 168                         return 0;
 169                 while (!req.complete)
 170                         pmu_poll();
 171                 if (req.reply_len != 0)
 172                         printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n",
 173                                req.reply_len);
 174                 return 1;
 175 #endif /* CONFIG_ADB_PMU */
 176         default:
 177                 return 0;
 178         }
 179 }
 180
 181 /*
 182  * Calibrate the decrementer register using VIA timer 1.
 183  * This is used both on powermacs and CHRP machines.
 184  */
 185 int __init
 186 via_calibrate_decr(void)
 187 {
 188         struct device_node *vias;
 189         volatile unsigned char __iomem *via;
 190         int count = VIA_TIMER_FREQ_6 / 100;
 191         unsigned int dstart, dend;
 192
 193         vias = find_devices("via-cuda");
 194         if (vias == 0)
 195                 vias = find_devices("via-pmu");
 196         if (vias == 0)
 197                 vias = find_devices("via");
 198         if (vias == 0 || vias->n_addrs == 0)
 199                 return 0;
 200         via = ioremap(vias->addrs[0].address, vias->addrs[0].size);
 201
 202         /* set timer 1 for continuous interrupts */
 203         out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
 204         /* set the counter to a small value */
 205         out_8(&via[T1CH], 2);
 206         /* set the latch to `count' */
 207         out_8(&via[T1LL], count);
 208         out_8(&via[T1LH], count >> 8);
 209         /* wait until it hits 0 */
 210         while ((in_8(&via[IFR]) & T1_INT) == 0)
 211                 ;
 212         dstart = get_dec();
 213         /* clear the interrupt & wait until it hits 0 again */
 214         in_8(&via[T1CL]);
 215         while ((in_8(&via[IFR]) & T1_INT) == 0)
 216                 ;
 217         dend = get_dec();
 218
 219         tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100);
 220         tb_to_us = mulhwu_scale_factor(dstart - dend, 60000);
 221
 222         printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %lu (%u ticks)\n",
 223                tb_ticks_per_jiffy, dstart - dend);
 224
 225         iounmap(via);
 226
 227         return 1;
 228 }
 229
 230 #ifdef CONFIG_PM
 231 /*
 232  * Reset the time after a sleep.
 233  */
 234 static int
 235 time_sleep_notify(struct pmu_sleep_notifier *self, int when)
 236 {
 237         static unsigned long time_diff;
 238         unsigned long flags;
 239         unsigned long seq;
 240         struct timespec tv;
 241
 242         switch (when) {
 243         case PBOOK_SLEEP_NOW:
 244                 do {
 245                         seq = read_seqbegin_irqsave(&xtime_lock, flags);
 246                         time_diff = xtime.tv_sec - pmac_get_boot_time();
 247                 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 248                 break;
 249         case PBOOK_WAKE:
 250                 tv.tv_sec = pmac_get_boot_time() + time_diff;
 251                 tv.tv_nsec = 0;
 252                 do_settimeofday(&tv);
 253                 break;
 254         }
 255         return PBOOK_SLEEP_OK;
 256 }
 257
 258 static struct pmu_sleep_notifier time_sleep_notifier = {
 259         time_sleep_notify, SLEEP_LEVEL_MISC,
 260 };
 261 #endif /* CONFIG_PM */
 262
 263 /*
 264  * Query the OF and get the decr frequency.
 265  * This was taken from the pmac time_init() when merging the prep/pmac
 266  * time functions.
 267  */
 268 void __init
 269 pmac_calibrate_decr(void)
 270 {
 271         struct device_node *cpu;
 272         unsigned int freq, *fp;
 273
 274 #ifdef CONFIG_PM
 275         pmu_register_sleep_notifier(&time_sleep_notifier);
 276 #endif /* CONFIG_PM */
 277
 278         /* We assume MacRISC2 machines have correct device-tree
 279          * calibration. That's better since the VIA itself seems
 280          * to be slightly off. --BenH
 281          */
 282         if (!machine_is_compatible("MacRISC2") &&
 283             !machine_is_compatible("MacRISC3") &&
 284             !machine_is_compatible("MacRISC4"))
 285                 if (via_calibrate_decr())
 286                         return;
 287
 288         /* Special case: QuickSilver G4s seem to have a badly calibrated
 289          * timebase-frequency in OF, VIA is much better on these. We should
 290          * probably implement calibration based on the KL timer on these
 291          * machines anyway... -BenH
 292          */
 293         if (machine_is_compatible("PowerMac3,5"))
 294                 if (via_calibrate_decr())
 295                         return;
 296         /*
 297          * The cpu node should have a timebase-frequency property
 298          * to tell us the rate at which the decrementer counts.
 299          */
 300         cpu = find_type_devices("cpu");
 301         if (cpu == 0)
 302                 panic("can't find cpu node in time_init");
 303         fp = (unsigned int *) get_property(cpu, "timebase-frequency", NULL);
 304         if (fp == 0)
 305                 panic("can't get cpu timebase frequency");
 306         freq = *fp;
 307         printk("time_init: decrementer frequency = %u.%.6u MHz\n",
 308                freq/1000000, freq%1000000);
 309         tb_ticks_per_jiffy = freq / HZ;
 310         tb_to_us = mulhwu_scale_factor(freq, 1000000);
 311 }