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 */
11
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/interrupt.h>
15 #include <linux/kernel_stat.h>
16 #include <linux/time.h>
17
18 #include <asm/cpu.h>
19 #include <asm/mipsregs.h>
20 #include <asm/io.h>
21 #include <asm/irq.h>
22 #include <asm/time.h>
23 #include <asm/ds1286.h>
24 #include <asm/sgialib.h>
25 #include <asm/sgi/ioc.h>
26 #include <asm/sgi/hpc3.h>
27 #include <asm/sgi/ip22.h>
28
29 /*
30 * note that mktime uses month from 1 to 12 while to_tm
31 * uses 0 to 11.
32 */
indy_rtc_get_time(void)33 static unsigned long indy_rtc_get_time(void)
34 {
35 unsigned int yrs, mon, day, hrs, min, sec;
36 unsigned int save_control;
37
38 save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff;
39 hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE;
40
41 sec = hpc3c0->rtcregs[RTC_SECONDS] & 0xff;
42 min = hpc3c0->rtcregs[RTC_MINUTES] & 0xff;
43 hrs = hpc3c0->rtcregs[RTC_HOURS] & 0x3f;
44 day = hpc3c0->rtcregs[RTC_DATE] & 0xff;
45 mon = hpc3c0->rtcregs[RTC_MONTH] & 0x1f;
46 yrs = hpc3c0->rtcregs[RTC_YEAR] & 0xff;
47
48 hpc3c0->rtcregs[RTC_CMD] = save_control;
49
50 BCD_TO_BIN(sec);
51 BCD_TO_BIN(min);
52 BCD_TO_BIN(hrs);
53 BCD_TO_BIN(day);
54 BCD_TO_BIN(mon);
55 BCD_TO_BIN(yrs);
56
57 if (yrs < 45)
58 yrs += 30;
59 if ((yrs += 40) < 70)
60 yrs += 100;
61
62 return mktime(yrs + 1900, mon, day, hrs, min, sec);
63 }
64
indy_rtc_set_time(unsigned long tim)65 static int indy_rtc_set_time(unsigned long tim)
66 {
67 struct rtc_time tm;
68 unsigned int save_control;
69
70 to_tm(tim, &tm);
71
72 tm.tm_mon += 1; /* tm_mon starts at zero */
73 tm.tm_year -= 1940;
74 if (tm.tm_year >= 100)
75 tm.tm_year -= 100;
76
77 BIN_TO_BCD(tm.tm_sec);
78 BIN_TO_BCD(tm.tm_min);
79 BIN_TO_BCD(tm.tm_hour);
80 BIN_TO_BCD(tm.tm_mday);
81 BIN_TO_BCD(tm.tm_mon);
82 BIN_TO_BCD(tm.tm_year);
83
84 save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff;
85 hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE;
86
87 hpc3c0->rtcregs[RTC_YEAR] = tm.tm_year;
88 hpc3c0->rtcregs[RTC_MONTH] = tm.tm_mon;
89 hpc3c0->rtcregs[RTC_DATE] = tm.tm_mday;
90 hpc3c0->rtcregs[RTC_HOURS] = tm.tm_hour;
91 hpc3c0->rtcregs[RTC_MINUTES] = tm.tm_min;
92 hpc3c0->rtcregs[RTC_SECONDS] = tm.tm_sec;
93 hpc3c0->rtcregs[RTC_HUNDREDTH_SECOND] = 0;
94
95 hpc3c0->rtcregs[RTC_CMD] = save_control;
96
97 return 0;
98 }
99
dosample(void)100 static unsigned long dosample(void)
101 {
102 u32 ct0, ct1;
103 volatile u8 msb, lsb;
104
105 /* Start the counter. */
106 sgint->tcword = (SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL |
107 SGINT_TCWORD_MRGEN);
108 sgint->tcnt2 = SGINT_TCSAMP_COUNTER & 0xff;
109 sgint->tcnt2 = SGINT_TCSAMP_COUNTER >> 8;
110
111 /* Get initial counter invariant */
112 ct0 = read_c0_count();
113
114 /* Latch and spin until top byte of counter2 is zero */
115 do {
116 sgint->tcword = SGINT_TCWORD_CNT2 | SGINT_TCWORD_CLAT;
117 lsb = sgint->tcnt2;
118 msb = sgint->tcnt2;
119 ct1 = read_c0_count();
120 } while (msb);
121
122 /* Stop the counter. */
123 sgint->tcword = (SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL |
124 SGINT_TCWORD_MSWST);
125 /*
126 * Return the difference, this is how far the r4k counter increments
127 * for every 1/HZ seconds. We round off the nearest 1 MHz of master
128 * clock (= 1000000 / HZ / 2).
129 */
130 /*return (ct1 - ct0 + (500000/HZ/2)) / (500000/HZ) * (500000/HZ);*/
131 return (ct1 - ct0) / (500000/HZ) * (500000/HZ);
132 }
133
134 /*
135 * Here we need to calibrate the cycle counter to at least be close.
136 */
indy_time_init(void)137 void indy_time_init(void)
138 {
139 unsigned long r4k_ticks[3];
140 unsigned long r4k_tick;
141
142 /*
143 * Figure out the r4k offset, the algorithm is very simple and works in
144 * _all_ cases as long as the 8254 counter register itself works ok (as
145 * an interrupt driving timer it does not because of bug, this is why
146 * we are using the onchip r4k counter/compare register to serve this
147 * purpose, but for r4k_offset calculation it will work ok for us).
148 * There are other very complicated ways of performing this calculation
149 * but this one works just fine so I am not going to futz around. ;-)
150 */
151 printk(KERN_INFO "Calibrating system timer... ");
152 dosample(); /* Prime cache. */
153 dosample(); /* Prime cache. */
154 /* Zero is NOT an option. */
155 do {
156 r4k_ticks[0] = dosample();
157 } while (!r4k_ticks[0]);
158 do {
159 r4k_ticks[1] = dosample();
160 } while (!r4k_ticks[1]);
161
162 if (r4k_ticks[0] != r4k_ticks[1]) {
163 printk("warning: timer counts differ, retrying... ");
164 r4k_ticks[2] = dosample();
165 if (r4k_ticks[2] == r4k_ticks[0]
166 || r4k_ticks[2] == r4k_ticks[1])
167 r4k_tick = r4k_ticks[2];
168 else {
169 printk("disagreement, using average... ");
170 r4k_tick = (r4k_ticks[0] + r4k_ticks[1]
171 + r4k_ticks[2]) / 3;
172 }
173 } else
174 r4k_tick = r4k_ticks[0];
175
176 printk("%d [%d.%04d MHz CPU]\n", (int) r4k_tick,
177 (int) (r4k_tick / (500000 / HZ)),
178 (int) (r4k_tick % (500000 / HZ)));
179
180 mips_hpt_frequency = r4k_tick * HZ;
181 }
182
183 /* Generic SGI handler for (spurious) 8254 interrupts */
indy_8254timer_irq(struct pt_regs * regs)184 void indy_8254timer_irq(struct pt_regs *regs)
185 {
186 int cpu = smp_processor_id();
187 int irq = SGI_8254_0_IRQ;
188 ULONG cnt;
189 char c;
190
191 irq_enter(cpu, irq);
192 kstat.irqs[cpu][irq]++;
193 printk(KERN_ALERT "Oops, got 8254 interrupt.\n");
194 ArcRead(0, &c, 1, &cnt);
195 ArcEnterInteractiveMode();
196 irq_exit(cpu, irq);
197 }
198
indy_r4k_timer_interrupt(struct pt_regs * regs)199 void indy_r4k_timer_interrupt(struct pt_regs *regs)
200 {
201 int cpu = smp_processor_id();
202 int irq = SGI_TIMER_IRQ;
203
204 irq_enter(cpu, irq);
205 kstat.irqs[cpu][irq]++;
206 timer_interrupt(irq, NULL, regs);
207 irq_exit(cpu, irq);
208
209 if (softirq_pending(cpu))
210 do_softirq();
211 }
212
213 extern int setup_irq(unsigned int irq, struct irqaction *irqaction);
214
indy_timer_setup(struct irqaction * irq)215 static void indy_timer_setup(struct irqaction *irq)
216 {
217 /* over-write the handler, we use our own way */
218 irq->handler = no_action;
219
220 /* setup irqaction */
221 setup_irq(SGI_TIMER_IRQ, irq);
222 }
223
ip22_time_init(void)224 void __init ip22_time_init(void)
225 {
226 /* setup hookup functions */
227 rtc_get_time = indy_rtc_get_time;
228 rtc_set_time = indy_rtc_set_time;
229
230 board_time_init = indy_time_init;
231 board_timer_setup = indy_timer_setup;
232 }
233