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