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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 | /* * Support for periodic interrupts (100 per second) and for getting * the current time from the RTC on Power Macintoshes. * * We use the decrementer register for our periodic interrupts. * * Paul Mackerras August 1996. * Copyright (C) 1996 Paul Mackerras. */ #include <linux/config.h> #include <linux/errno.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/param.h> #include <linux/string.h> #include <linux/mm.h> #include <linux/init.h> #include <asm/adb.h> #include <asm/cuda.h> #include <asm/pmu.h> #include <asm/prom.h> #include <asm/system.h> #include <asm/io.h> #include <asm/pgtable.h> #include "time.h" /* Apparently the RTC stores seconds since 1 Jan 1904 */ #define RTC_OFFSET 2082844800 /* * Calibrate the decrementer frequency with the VIA timer 1. */ #define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */ /* VIA registers */ #define RS 0x200 /* skip between registers */ #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */ #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */ #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */ #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */ #define ACR (11*RS) /* Auxiliary control register */ #define IFR (13*RS) /* Interrupt flag register */ /* Bits in ACR */ #define T1MODE 0xc0 /* Timer 1 mode */ #define T1MODE_CONT 0x40 /* continuous interrupts */ /* Bits in IFR and IER */ #define T1_INT 0x40 /* Timer 1 interrupt */ __pmac unsigned long pmac_get_rtc_time(void) { struct adb_request req; /* Get the time from the RTC */ switch (adb_hardware) { case ADB_VIACUDA: if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0) return 0; while (!req.complete) cuda_poll(); if (req.reply_len != 7) printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n", req.reply_len); return (req.reply[3] << 24) + (req.reply[4] << 16) + (req.reply[5] << 8) + req.reply[6] - RTC_OFFSET; case ADB_VIAPMU: if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0) return 0; while (!req.complete) pmu_poll(); if (req.reply_len != 5) printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n", req.reply_len); return (req.reply[1] << 24) + (req.reply[2] << 16) + (req.reply[3] << 8) + req.reply[4] - RTC_OFFSET; default: return 0; } } int pmac_set_rtc_time(unsigned long nowtime) { return 0; } /* * Calibrate the decrementer register using VIA timer 1. * This is used both on powermacs and CHRP machines. */ __initfunc(int via_calibrate_decr(void)) { struct device_node *vias; volatile unsigned char *via; int count = VIA_TIMER_FREQ_6 / HZ; unsigned int dstart, dend; vias = find_devices("via-cuda"); if (vias == 0) vias = find_devices("via-pmu"); if (vias == 0) vias = find_devices("via"); if (vias == 0 || vias->n_addrs == 0) return 0; via = (volatile unsigned char *) ioremap(vias->addrs[0].address, vias->addrs[0].size); /* set timer 1 for continuous interrupts */ out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT); /* set the counter to a small value */ out_8(&via[T1CH], 2); /* set the latch to `count' */ out_8(&via[T1LL], count); out_8(&via[T1LH], count >> 8); /* wait until it hits 0 */ while ((in_8(&via[IFR]) & T1_INT) == 0) ; dstart = get_dec(); /* clear the interrupt & wait until it hits 0 again */ in_8(&via[T1CL]); while ((in_8(&via[IFR]) & T1_INT) == 0) ; dend = get_dec(); decrementer_count = (dstart - dend) / 6; count_period_num = 60; count_period_den = decrementer_count * 6 * HZ / 100000; printk(KERN_INFO "via_calibrate_decr: decrementer_count = %u (%u ticks)\n", decrementer_count, dstart - dend); return 1; } #ifdef CONFIG_PMAC_PBOOK /* * Reset the time after a sleep. */ static int time_sleep_notify(struct notifier_block *this, unsigned long event, void *x) { static unsigned long time_diff; switch (event) { case PBOOK_SLEEP: time_diff = xtime.tv_sec - pmac_get_rtc_time(); break; case PBOOK_WAKE: xtime.tv_sec = pmac_get_rtc_time() + time_diff; xtime.tv_usec = 0; set_dec(decrementer_count); last_rtc_update = xtime.tv_sec; break; } return NOTIFY_DONE; } static struct notifier_block time_sleep_notifier = { time_sleep_notify, NULL, 100 }; #endif /* CONFIG_PMAC_PBOOK */ /* * Query the OF and get the decr frequency. * This was taken from the pmac time_init() when merging the prep/pmac * time functions. */ __initfunc(void pmac_calibrate_decr(void)) { struct device_node *cpu; int freq, *fp, divisor; #ifdef CONFIG_PMAC_PBOOK notifier_chain_register(&sleep_notifier_list, &time_sleep_notifier); #endif /* CONFIG_PMAC_PBOOK */ if (via_calibrate_decr()) return; /* * The cpu node should have a timebase-frequency property * to tell us the rate at which the decrementer counts. */ cpu = find_type_devices("cpu"); if (cpu == 0) panic("can't find cpu node in time_init"); fp = (int *) get_property(cpu, "timebase-frequency", NULL); if (fp == 0) panic("can't get cpu timebase frequency"); freq = *fp * 60; /* try to make freq/1e6 an integer */ divisor = 60; printk("time_init: decrementer frequency = %d/%d\n", freq, divisor); decrementer_count = freq / HZ / divisor; count_period_num = divisor; count_period_den = freq / 1000000; } |