xref: /openbmc/linux/arch/mips/sgi-ip27/ip27-timer.c (revision e887b245)
1 /*
2  * Copytight (C) 1999, 2000, 05, 06 Ralf Baechle (ralf@linux-mips.org)
3  * Copytight (C) 1999, 2000 Silicon Graphics, Inc.
4  */
5 #include <linux/bcd.h>
6 #include <linux/clockchips.h>
7 #include <linux/init.h>
8 #include <linux/kernel.h>
9 #include <linux/sched.h>
10 #include <linux/interrupt.h>
11 #include <linux/kernel_stat.h>
12 #include <linux/param.h>
13 #include <linux/time.h>
14 #include <linux/timex.h>
15 #include <linux/mm.h>
16 
17 #include <asm/time.h>
18 #include <asm/pgtable.h>
19 #include <asm/sgialib.h>
20 #include <asm/sn/ioc3.h>
21 #include <asm/m48t35.h>
22 #include <asm/sn/klconfig.h>
23 #include <asm/sn/arch.h>
24 #include <asm/sn/addrs.h>
25 #include <asm/sn/sn_private.h>
26 #include <asm/sn/sn0/ip27.h>
27 #include <asm/sn/sn0/hub.h>
28 
29 #define TICK_SIZE (tick_nsec / 1000)
30 
31 #if 0
32 static int set_rtc_mmss(unsigned long nowtime)
33 {
34 	int retval = 0;
35 	int real_seconds, real_minutes, cmos_minutes;
36 	struct m48t35_rtc *rtc;
37 	nasid_t nid;
38 
39 	nid = get_nasid();
40 	rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
41 							IOC3_BYTEBUS_DEV0);
42 
43 	rtc->control |= M48T35_RTC_READ;
44 	cmos_minutes = BCD2BIN(rtc->min);
45 	rtc->control &= ~M48T35_RTC_READ;
46 
47 	/*
48 	 * Since we're only adjusting minutes and seconds, don't interfere with
49 	 * hour overflow. This avoids messing with unknown time zones but
50 	 * requires your RTC not to be off by more than 15 minutes
51 	 */
52 	real_seconds = nowtime % 60;
53 	real_minutes = nowtime / 60;
54 	if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
55 		real_minutes += 30;	/* correct for half hour time zone */
56 	real_minutes %= 60;
57 
58 	if (abs(real_minutes - cmos_minutes) < 30) {
59 		real_seconds = BIN2BCD(real_seconds);
60 		real_minutes = BIN2BCD(real_minutes);
61 		rtc->control |= M48T35_RTC_SET;
62 		rtc->sec = real_seconds;
63 		rtc->min = real_minutes;
64 		rtc->control &= ~M48T35_RTC_SET;
65 	} else {
66 		printk(KERN_WARNING
67 		       "set_rtc_mmss: can't update from %d to %d\n",
68 		       cmos_minutes, real_minutes);
69 		retval = -1;
70 	}
71 
72 	return retval;
73 }
74 #endif
75 
76 /* Includes for ioc3_init().  */
77 #include <asm/sn/types.h>
78 #include <asm/sn/sn0/addrs.h>
79 #include <asm/sn/sn0/hubni.h>
80 #include <asm/sn/sn0/hubio.h>
81 #include <asm/pci/bridge.h>
82 
83 unsigned long read_persistent_clock(void)
84 {
85         unsigned int year, month, date, hour, min, sec;
86 	struct m48t35_rtc *rtc;
87 	nasid_t nid;
88 
89 	nid = get_nasid();
90 	rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
91 							IOC3_BYTEBUS_DEV0);
92 
93 	rtc->control |= M48T35_RTC_READ;
94 	sec = rtc->sec;
95 	min = rtc->min;
96 	hour = rtc->hour;
97 	date = rtc->date;
98 	month = rtc->month;
99 	year = rtc->year;
100 	rtc->control &= ~M48T35_RTC_READ;
101 
102         sec = BCD2BIN(sec);
103         min = BCD2BIN(min);
104         hour = BCD2BIN(hour);
105         date = BCD2BIN(date);
106         month = BCD2BIN(month);
107         year = BCD2BIN(year);
108 
109         year += 1970;
110 
111         return mktime(year, month, date, hour, min, sec);
112 }
113 
114 static int rt_set_next_event(unsigned long delta,
115 		struct clock_event_device *evt)
116 {
117 	unsigned int cpu = smp_processor_id();
118 	int slice = cputoslice(cpu) == 0;
119 	unsigned long cnt;
120 
121 	cnt = LOCAL_HUB_L(PI_RT_COUNT);
122 	cnt += delta;
123 	LOCAL_HUB_S(slice ? PI_RT_COMPARE_A : PI_RT_COMPARE_B, cnt);
124 
125 	return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
126 }
127 
128 static void rt_set_mode(enum clock_event_mode mode,
129 		struct clock_event_device *evt)
130 {
131 	switch (mode) {
132 	case CLOCK_EVT_MODE_PERIODIC:
133 		/* The only mode supported */
134 		break;
135 
136 	case CLOCK_EVT_MODE_UNUSED:
137 	case CLOCK_EVT_MODE_SHUTDOWN:
138 	case CLOCK_EVT_MODE_ONESHOT:
139 	case CLOCK_EVT_MODE_RESUME:
140 		/* Nothing to do  */
141 		break;
142 	}
143 }
144 
145 struct clock_event_device rt_clock_event_device = {
146 	.name		= "HUB-RT",
147 	.features	= CLOCK_EVT_FEAT_ONESHOT,
148 
149 	.rating		= 300,
150 	.set_next_event	= rt_set_next_event,
151 	.set_mode	= rt_set_mode,
152 };
153 
154 static void enable_rt_irq(unsigned int irq)
155 {
156 }
157 
158 static void disable_rt_irq(unsigned int irq)
159 {
160 }
161 
162 static struct irq_chip rt_irq_type = {
163 	.name		= "SN HUB RT timer",
164 	.ack		= disable_rt_irq,
165 	.mask		= disable_rt_irq,
166 	.mask_ack	= disable_rt_irq,
167 	.unmask		= enable_rt_irq,
168 	.eoi		= enable_rt_irq,
169 };
170 
171 unsigned int rt_timer_irq;
172 
173 static irqreturn_t ip27_rt_timer_interrupt(int irq, void *dev_id)
174 {
175 	struct clock_event_device *cd = &rt_clock_event_device;
176 	unsigned int cpu = smp_processor_id();
177 	int slice = cputoslice(cpu) == 0;
178 
179 	LOCAL_HUB_S(slice ? PI_RT_PEND_A : PI_RT_PEND_B, 0);	/* Ack  */
180 	cd->event_handler(cd);
181 
182 	return IRQ_HANDLED;
183 }
184 
185 static struct irqaction rt_irqaction = {
186 	.handler	= (irq_handler_t) ip27_rt_timer_interrupt,
187 	.flags		= IRQF_DISABLED,
188 	.mask		= CPU_MASK_NONE,
189 	.name		= "timer"
190 };
191 
192 /*
193  * This is a hack; we really need to figure these values out dynamically
194  *
195  * Since 800 ns works very well with various HUB frequencies, such as
196  * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
197  *
198  * Ralf: which clock rate is used to feed the counter?
199  */
200 #define NSEC_PER_CYCLE		800
201 #define CYCLES_PER_SEC		(NSEC_PER_SEC / NSEC_PER_CYCLE)
202 
203 static void __init ip27_rt_clock_event_init(void)
204 {
205 	struct clock_event_device *cd = &rt_clock_event_device;
206 	unsigned int cpu = smp_processor_id();
207 	int irq = allocate_irqno();
208 
209 	if (irq < 0)
210 		panic("Can't allocate interrupt number for timer interrupt");
211 
212 	rt_timer_irq = irq;
213 
214 	cd->irq			= irq,
215 	cd->cpumask		= cpumask_of_cpu(cpu),
216 
217 	/*
218 	 * Calculate the min / max delta
219 	 */
220 	cd->mult        	=
221 		div_sc((unsigned long) CYCLES_PER_SEC, NSEC_PER_SEC, 32);
222 	cd->shift               = 32;
223 	cd->max_delta_ns        = clockevent_delta2ns(0x7fffffff, cd);
224 	cd->min_delta_ns        = clockevent_delta2ns(0x300, cd);
225 	clockevents_register_device(cd);
226 
227 	set_irq_chip_and_handler(irq, &rt_irq_type, handle_percpu_irq);
228 	setup_irq(irq, &rt_irqaction);
229 }
230 
231 static cycle_t hub_rt_read(void)
232 {
233 	return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
234 }
235 
236 struct clocksource ht_rt_clocksource = {
237 	.name	= "HUB-RT",
238 	.rating	= 200,
239 	.read	= hub_rt_read,
240 	.mask	= CLOCKSOURCE_MASK(52),
241 	.shift	= 32,
242 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
243 };
244 
245 static void __init ip27_rt_clocksource_init(void)
246 {
247 	clocksource_register(&ht_rt_clocksource);
248 }
249 
250 void __init plat_time_init(void)
251 {
252 	ip27_rt_clock_event_init();
253 	ip27_rt_clocksource_init();
254 }
255 
256 void __init cpu_time_init(void)
257 {
258 	lboard_t *board;
259 	klcpu_t *cpu;
260 	int cpuid;
261 
262 	/* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
263 	board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
264 	if (!board)
265 		panic("Can't find board info for myself.");
266 
267 	cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
268 	cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
269 	if (!cpu)
270 		panic("No information about myself?");
271 
272 	printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
273 
274 	set_c0_status(SRB_TIMOCLK);
275 }
276 
277 void __init hub_rtc_init(cnodeid_t cnode)
278 {
279 	/*
280 	 * We only need to initialize the current node.
281 	 * If this is not the current node then it is a cpuless
282 	 * node and timeouts will not happen there.
283 	 */
284 	if (get_compact_nodeid() == cnode) {
285 		LOCAL_HUB_S(PI_RT_EN_A, 1);
286 		LOCAL_HUB_S(PI_RT_EN_B, 1);
287 		LOCAL_HUB_S(PI_PROF_EN_A, 0);
288 		LOCAL_HUB_S(PI_PROF_EN_B, 0);
289 		LOCAL_HUB_S(PI_RT_COUNT, 0);
290 		LOCAL_HUB_S(PI_RT_PEND_A, 0);
291 		LOCAL_HUB_S(PI_RT_PEND_B, 0);
292 	}
293 }
294