xref: /openbmc/linux/arch/sparc/kernel/time_32.c (revision 4cfb9080) 
1 // SPDX-License-Identifier: GPL-2.0
2 /* linux/arch/sparc/kernel/time.c
3  *
4  * Copyright (C) 1995 David S. Miller (davem@davemloft.net)
5  * Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
6  *
7  * Chris Davis (cdavis@cois.on.ca) 03/27/1998
8  * Added support for the intersil on the sun4/4200
9  *
10  * Gleb Raiko (rajko@mech.math.msu.su) 08/18/1998
11  * Support for MicroSPARC-IIep, PCI CPU.
12  *
13  * This file handles the Sparc specific time handling details.
14  *
15  * 1997-09-10	Updated NTP code according to technical memorandum Jan '96
16  *		"A Kernel Model for Precision Timekeeping" by Dave Mills
17  */
18 #include <linux/errno.h>
19 #include <linux/module.h>
20 #include <linux/sched.h>
21 #include <linux/kernel.h>
22 #include <linux/param.h>
23 #include <linux/string.h>
24 #include <linux/mm.h>
25 #include <linux/interrupt.h>
26 #include <linux/time.h>
27 #include <linux/rtc/m48t59.h>
28 #include <linux/timex.h>
29 #include <linux/clocksource.h>
30 #include <linux/clockchips.h>
31 #include <linux/init.h>
32 #include <linux/pci.h>
33 #include <linux/ioport.h>
34 #include <linux/profile.h>
35 #include <linux/of.h>
36 #include <linux/of_device.h>
37 #include <linux/platform_device.h>
38 
39 #include <asm/mc146818rtc.h>
40 #include <asm/oplib.h>
41 #include <asm/timex.h>
42 #include <asm/timer.h>
43 #include <asm/irq.h>
44 #include <asm/io.h>
45 #include <asm/idprom.h>
46 #include <asm/page.h>
47 #include <asm/pcic.h>
48 #include <asm/irq_regs.h>
49 #include <asm/setup.h>
50 
51 #include "kernel.h"
52 #include "irq.h"
53 
54 static __cacheline_aligned_in_smp DEFINE_SEQLOCK(timer_cs_lock);
55 static __volatile__ u64 timer_cs_internal_counter = 0;
56 static char timer_cs_enabled = 0;
57 
58 static struct clock_event_device timer_ce;
59 static char timer_ce_enabled = 0;
60 
61 #ifdef CONFIG_SMP
62 DEFINE_PER_CPU(struct clock_event_device, sparc32_clockevent);
63 #endif
64 
65 DEFINE_SPINLOCK(rtc_lock);
66 EXPORT_SYMBOL(rtc_lock);
67 
68 unsigned long profile_pc(struct pt_regs *regs)
69 {
70 	extern char __copy_user_begin[], __copy_user_end[];
71 	extern char __bzero_begin[], __bzero_end[];
72 
73 	unsigned long pc = regs->pc;
74 
75 	if (in_lock_functions(pc) ||
76 	    (pc >= (unsigned long) __copy_user_begin &&
77 	     pc < (unsigned long) __copy_user_end) ||
78 	    (pc >= (unsigned long) __bzero_begin &&
79 	     pc < (unsigned long) __bzero_end))
80 		pc = regs->u_regs[UREG_RETPC];
81 	return pc;
82 }
83 
84 EXPORT_SYMBOL(profile_pc);
85 
86 volatile u32 __iomem *master_l10_counter;
87 
88 irqreturn_t notrace timer_interrupt(int dummy, void *dev_id)
89 {
90 	if (timer_cs_enabled) {
91 		write_seqlock(&timer_cs_lock);
92 		timer_cs_internal_counter++;
93 		sparc_config.clear_clock_irq();
94 		write_sequnlock(&timer_cs_lock);
95 	} else {
96 		sparc_config.clear_clock_irq();
97 	}
98 
99 	if (timer_ce_enabled)
100 		timer_ce.event_handler(&timer_ce);
101 
102 	return IRQ_HANDLED;
103 }
104 
105 static int timer_ce_shutdown(struct clock_event_device *evt)
106 {
107 	timer_ce_enabled = 0;
108 	smp_mb();
109 	return 0;
110 }
111 
112 static int timer_ce_set_periodic(struct clock_event_device *evt)
113 {
114 	timer_ce_enabled = 1;
115 	smp_mb();
116 	return 0;
117 }
118 
119 static __init void setup_timer_ce(void)
120 {
121 	struct clock_event_device *ce = &timer_ce;
122 
123 	BUG_ON(smp_processor_id() != boot_cpu_id);
124 
125 	ce->name     = "timer_ce";
126 	ce->rating   = 100;
127 	ce->features = CLOCK_EVT_FEAT_PERIODIC;
128 	ce->set_state_shutdown = timer_ce_shutdown;
129 	ce->set_state_periodic = timer_ce_set_periodic;
130 	ce->tick_resume = timer_ce_set_periodic;
131 	ce->cpumask  = cpu_possible_mask;
132 	ce->shift    = 32;
133 	ce->mult     = div_sc(sparc_config.clock_rate, NSEC_PER_SEC,
134 	                      ce->shift);
135 	clockevents_register_device(ce);
136 }
137 
138 static unsigned int sbus_cycles_offset(void)
139 {
140 	u32 val, offset;
141 
142 	val = sbus_readl(master_l10_counter);
143 	offset = (val >> TIMER_VALUE_SHIFT) & TIMER_VALUE_MASK;
144 
145 	/* Limit hit? */
146 	if (val & TIMER_LIMIT_BIT)
147 		offset += sparc_config.cs_period;
148 
149 	return offset;
150 }
151 
152 static u64 timer_cs_read(struct clocksource *cs)
153 {
154 	unsigned int seq, offset;
155 	u64 cycles;
156 
157 	do {
158 		seq = read_seqbegin(&timer_cs_lock);
159 
160 		cycles = timer_cs_internal_counter;
161 		offset = sparc_config.get_cycles_offset();
162 	} while (read_seqretry(&timer_cs_lock, seq));
163 
164 	/* Count absolute cycles */
165 	cycles *= sparc_config.cs_period;
166 	cycles += offset;
167 
168 	return cycles;
169 }
170 
171 static struct clocksource timer_cs = {
172 	.name	= "timer_cs",
173 	.rating	= 100,
174 	.read	= timer_cs_read,
175 	.mask	= CLOCKSOURCE_MASK(64),
176 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
177 };
178 
179 static __init int setup_timer_cs(void)
180 {
181 	timer_cs_enabled = 1;
182 	return clocksource_register_hz(&timer_cs, sparc_config.clock_rate);
183 }
184 
185 #ifdef CONFIG_SMP
186 static int percpu_ce_shutdown(struct clock_event_device *evt)
187 {
188 	int cpu = cpumask_first(evt->cpumask);
189 
190 	sparc_config.load_profile_irq(cpu, 0);
191 	return 0;
192 }
193 
194 static int percpu_ce_set_periodic(struct clock_event_device *evt)
195 {
196 	int cpu = cpumask_first(evt->cpumask);
197 
198 	sparc_config.load_profile_irq(cpu, SBUS_CLOCK_RATE / HZ);
199 	return 0;
200 }
201 
202 static int percpu_ce_set_next_event(unsigned long delta,
203 				    struct clock_event_device *evt)
204 {
205 	int cpu = cpumask_first(evt->cpumask);
206 	unsigned int next = (unsigned int)delta;
207 
208 	sparc_config.load_profile_irq(cpu, next);
209 	return 0;
210 }
211 
212 void register_percpu_ce(int cpu)
213 {
214 	struct clock_event_device *ce = &per_cpu(sparc32_clockevent, cpu);
215 	unsigned int features = CLOCK_EVT_FEAT_PERIODIC;
216 
217 	if (sparc_config.features & FEAT_L14_ONESHOT)
218 		features |= CLOCK_EVT_FEAT_ONESHOT;
219 
220 	ce->name           = "percpu_ce";
221 	ce->rating         = 200;
222 	ce->features       = features;
223 	ce->set_state_shutdown = percpu_ce_shutdown;
224 	ce->set_state_periodic = percpu_ce_set_periodic;
225 	ce->set_state_oneshot = percpu_ce_shutdown;
226 	ce->set_next_event = percpu_ce_set_next_event;
227 	ce->cpumask        = cpumask_of(cpu);
228 	ce->shift          = 32;
229 	ce->mult           = div_sc(sparc_config.clock_rate, NSEC_PER_SEC,
230 	                            ce->shift);
231 	ce->max_delta_ns   = clockevent_delta2ns(sparc_config.clock_rate, ce);
232 	ce->max_delta_ticks = (unsigned long)sparc_config.clock_rate;
233 	ce->min_delta_ns   = clockevent_delta2ns(100, ce);
234 	ce->min_delta_ticks = 100;
235 
236 	clockevents_register_device(ce);
237 }
238 #endif
239 
240 static unsigned char mostek_read_byte(struct device *dev, u32 ofs)
241 {
242 	struct platform_device *pdev = to_platform_device(dev);
243 	struct m48t59_plat_data *pdata = pdev->dev.platform_data;
244 
245 	return readb(pdata->ioaddr + ofs);
246 }
247 
248 static void mostek_write_byte(struct device *dev, u32 ofs, u8 val)
249 {
250 	struct platform_device *pdev = to_platform_device(dev);
251 	struct m48t59_plat_data *pdata = pdev->dev.platform_data;
252 
253 	writeb(val, pdata->ioaddr + ofs);
254 }
255 
256 static struct m48t59_plat_data m48t59_data = {
257 	.read_byte = mostek_read_byte,
258 	.write_byte = mostek_write_byte,
259 };
260 
261 /* resource is set at runtime */
262 static struct platform_device m48t59_rtc = {
263 	.name		= "rtc-m48t59",
264 	.id		= 0,
265 	.num_resources	= 1,
266 	.dev	= {
267 		.platform_data = &m48t59_data,
268 	},
269 };
270 
271 static int clock_probe(struct platform_device *op)
272 {
273 	struct device_node *dp = op->dev.of_node;
274 	const char *model = of_get_property(dp, "model", NULL);
275 
276 	if (!model)
277 		return -ENODEV;
278 
279 	/* Only the primary RTC has an address property */
280 	if (!of_property_present(dp, "address"))
281 		return -ENODEV;
282 
283 	m48t59_rtc.resource = &op->resource[0];
284 	if (!strcmp(model, "mk48t02")) {
285 		/* Map the clock register io area read-only */
286 		m48t59_data.ioaddr = of_ioremap(&op->resource[0], 0,
287 						2048, "rtc-m48t59");
288 		m48t59_data.type = M48T59RTC_TYPE_M48T02;
289 	} else if (!strcmp(model, "mk48t08")) {
290 		m48t59_data.ioaddr = of_ioremap(&op->resource[0], 0,
291 						8192, "rtc-m48t59");
292 		m48t59_data.type = M48T59RTC_TYPE_M48T08;
293 	} else
294 		return -ENODEV;
295 
296 	if (platform_device_register(&m48t59_rtc) < 0)
297 		printk(KERN_ERR "Registering RTC device failed\n");
298 
299 	return 0;
300 }
301 
302 static const struct of_device_id clock_match[] = {
303 	{
304 		.name = "eeprom",
305 	},
306 	{},
307 };
308 
309 static struct platform_driver clock_driver = {
310 	.probe		= clock_probe,
311 	.driver = {
312 		.name = "rtc",
313 		.of_match_table = clock_match,
314 	},
315 };
316 
317 
318 /* Probe for the mostek real time clock chip. */
319 static int __init clock_init(void)
320 {
321 	return platform_driver_register(&clock_driver);
322 }
323 /* Must be after subsys_initcall() so that busses are probed.  Must
324  * be before device_initcall() because things like the RTC driver
325  * need to see the clock registers.
326  */
327 fs_initcall(clock_init);
328 
329 static void __init sparc32_late_time_init(void)
330 {
331 	if (sparc_config.features & FEAT_L10_CLOCKEVENT)
332 		setup_timer_ce();
333 	if (sparc_config.features & FEAT_L10_CLOCKSOURCE)
334 		setup_timer_cs();
335 #ifdef CONFIG_SMP
336 	register_percpu_ce(smp_processor_id());
337 #endif
338 }
339 
340 static void __init sbus_time_init(void)
341 {
342 	sparc_config.get_cycles_offset = sbus_cycles_offset;
343 	sparc_config.init_timers();
344 }
345 
346 void __init time_init(void)
347 {
348 	sparc_config.features = 0;
349 	late_time_init = sparc32_late_time_init;
350 
351 	if (pcic_present())
352 		pci_time_init();
353 	else
354 		sbus_time_init();
355 }
356 
357