1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Time operations for IP22 machines. Original code may come from 7 * Ralf Baechle or David S. Miller (sorry guys, i'm really not sure) 8 * 9 * Copyright (C) 2001 by Ladislav Michl 10 * Copyright (C) 2003 Ralf Baechle (ralf@linux-mips.org) 11 */ 12 #include <linux/bcd.h> 13 #include <linux/ds1286.h> 14 #include <linux/init.h> 15 #include <linux/kernel.h> 16 #include <linux/interrupt.h> 17 #include <linux/kernel_stat.h> 18 #include <linux/time.h> 19 20 #include <asm/cpu.h> 21 #include <asm/mipsregs.h> 22 #include <asm/io.h> 23 #include <asm/irq.h> 24 #include <asm/time.h> 25 #include <asm/sgialib.h> 26 #include <asm/sgi/ioc.h> 27 #include <asm/sgi/hpc3.h> 28 #include <asm/sgi/ip22.h> 29 30 /* 31 * note that mktime uses month from 1 to 12 while to_tm 32 * uses 0 to 11. 33 */ 34 static unsigned long indy_rtc_get_time(void) 35 { 36 unsigned int yrs, mon, day, hrs, min, sec; 37 unsigned int save_control; 38 unsigned long flags; 39 40 spin_lock_irqsave(&rtc_lock, flags); 41 save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff; 42 hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE; 43 44 sec = BCD2BIN(hpc3c0->rtcregs[RTC_SECONDS] & 0xff); 45 min = BCD2BIN(hpc3c0->rtcregs[RTC_MINUTES] & 0xff); 46 hrs = BCD2BIN(hpc3c0->rtcregs[RTC_HOURS] & 0x3f); 47 day = BCD2BIN(hpc3c0->rtcregs[RTC_DATE] & 0xff); 48 mon = BCD2BIN(hpc3c0->rtcregs[RTC_MONTH] & 0x1f); 49 yrs = BCD2BIN(hpc3c0->rtcregs[RTC_YEAR] & 0xff); 50 51 hpc3c0->rtcregs[RTC_CMD] = save_control; 52 spin_unlock_irqrestore(&rtc_lock, flags); 53 54 if (yrs < 45) 55 yrs += 30; 56 if ((yrs += 40) < 70) 57 yrs += 100; 58 59 return mktime(yrs + 1900, mon, day, hrs, min, sec); 60 } 61 62 static int indy_rtc_set_time(unsigned long tim) 63 { 64 struct rtc_time tm; 65 unsigned int save_control; 66 unsigned long flags; 67 68 to_tm(tim, &tm); 69 70 tm.tm_mon += 1; /* tm_mon starts at zero */ 71 tm.tm_year -= 1940; 72 if (tm.tm_year >= 100) 73 tm.tm_year -= 100; 74 75 spin_lock_irqsave(&rtc_lock, flags); 76 save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff; 77 hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE; 78 79 hpc3c0->rtcregs[RTC_YEAR] = BIN2BCD(tm.tm_sec); 80 hpc3c0->rtcregs[RTC_MONTH] = BIN2BCD(tm.tm_mon); 81 hpc3c0->rtcregs[RTC_DATE] = BIN2BCD(tm.tm_mday); 82 hpc3c0->rtcregs[RTC_HOURS] = BIN2BCD(tm.tm_hour); 83 hpc3c0->rtcregs[RTC_MINUTES] = BIN2BCD(tm.tm_min); 84 hpc3c0->rtcregs[RTC_SECONDS] = BIN2BCD(tm.tm_sec); 85 hpc3c0->rtcregs[RTC_HUNDREDTH_SECOND] = 0; 86 87 hpc3c0->rtcregs[RTC_CMD] = save_control; 88 spin_unlock_irqrestore(&rtc_lock, flags); 89 90 return 0; 91 } 92 93 static unsigned long dosample(void) 94 { 95 u32 ct0, ct1; 96 volatile u8 msb, lsb; 97 98 /* Start the counter. */ 99 sgint->tcword = (SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL | 100 SGINT_TCWORD_MRGEN); 101 sgint->tcnt2 = SGINT_TCSAMP_COUNTER & 0xff; 102 sgint->tcnt2 = SGINT_TCSAMP_COUNTER >> 8; 103 104 /* Get initial counter invariant */ 105 ct0 = read_c0_count(); 106 107 /* Latch and spin until top byte of counter2 is zero */ 108 do { 109 sgint->tcword = SGINT_TCWORD_CNT2 | SGINT_TCWORD_CLAT; 110 lsb = sgint->tcnt2; 111 msb = sgint->tcnt2; 112 ct1 = read_c0_count(); 113 } while (msb); 114 115 /* Stop the counter. */ 116 sgint->tcword = (SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL | 117 SGINT_TCWORD_MSWST); 118 /* 119 * Return the difference, this is how far the r4k counter increments 120 * for every 1/HZ seconds. We round off the nearest 1 MHz of master 121 * clock (= 1000000 / HZ / 2). 122 */ 123 /*return (ct1 - ct0 + (500000/HZ/2)) / (500000/HZ) * (500000/HZ);*/ 124 return (ct1 - ct0) / (500000/HZ) * (500000/HZ); 125 } 126 127 /* 128 * Here we need to calibrate the cycle counter to at least be close. 129 */ 130 static __init void indy_time_init(void) 131 { 132 unsigned long r4k_ticks[3]; 133 unsigned long r4k_tick; 134 135 /* 136 * Figure out the r4k offset, the algorithm is very simple and works in 137 * _all_ cases as long as the 8254 counter register itself works ok (as 138 * an interrupt driving timer it does not because of bug, this is why 139 * we are using the onchip r4k counter/compare register to serve this 140 * purpose, but for r4k_offset calculation it will work ok for us). 141 * There are other very complicated ways of performing this calculation 142 * but this one works just fine so I am not going to futz around. ;-) 143 */ 144 printk(KERN_INFO "Calibrating system timer... "); 145 dosample(); /* Prime cache. */ 146 dosample(); /* Prime cache. */ 147 /* Zero is NOT an option. */ 148 do { 149 r4k_ticks[0] = dosample(); 150 } while (!r4k_ticks[0]); 151 do { 152 r4k_ticks[1] = dosample(); 153 } while (!r4k_ticks[1]); 154 155 if (r4k_ticks[0] != r4k_ticks[1]) { 156 printk("warning: timer counts differ, retrying... "); 157 r4k_ticks[2] = dosample(); 158 if (r4k_ticks[2] == r4k_ticks[0] 159 || r4k_ticks[2] == r4k_ticks[1]) 160 r4k_tick = r4k_ticks[2]; 161 else { 162 printk("disagreement, using average... "); 163 r4k_tick = (r4k_ticks[0] + r4k_ticks[1] 164 + r4k_ticks[2]) / 3; 165 } 166 } else 167 r4k_tick = r4k_ticks[0]; 168 169 printk("%d [%d.%04d MHz CPU]\n", (int) r4k_tick, 170 (int) (r4k_tick / (500000 / HZ)), 171 (int) (r4k_tick % (500000 / HZ))); 172 173 mips_hpt_frequency = r4k_tick * HZ; 174 } 175 176 /* Generic SGI handler for (spurious) 8254 interrupts */ 177 void indy_8254timer_irq(struct pt_regs *regs) 178 { 179 int irq = SGI_8254_0_IRQ; 180 ULONG cnt; 181 char c; 182 183 irq_enter(); 184 kstat_this_cpu.irqs[irq]++; 185 printk(KERN_ALERT "Oops, got 8254 interrupt.\n"); 186 ArcRead(0, &c, 1, &cnt); 187 ArcEnterInteractiveMode(); 188 irq_exit(); 189 } 190 191 void indy_r4k_timer_interrupt(struct pt_regs *regs) 192 { 193 int irq = SGI_TIMER_IRQ; 194 195 irq_enter(); 196 kstat_this_cpu.irqs[irq]++; 197 timer_interrupt(irq, NULL, regs); 198 irq_exit(); 199 } 200 201 extern int setup_irq(unsigned int irq, struct irqaction *irqaction); 202 203 static void indy_timer_setup(struct irqaction *irq) 204 { 205 /* over-write the handler, we use our own way */ 206 irq->handler = no_action; 207 208 /* setup irqaction */ 209 setup_irq(SGI_TIMER_IRQ, irq); 210 } 211 212 void __init ip22_time_init(void) 213 { 214 /* setup hookup functions */ 215 rtc_get_time = indy_rtc_get_time; 216 rtc_set_time = indy_rtc_set_time; 217 218 board_time_init = indy_time_init; 219 board_timer_setup = indy_timer_setup; 220 } 221