xref: /openbmc/linux/arch/sparc/kernel/time_32.c (revision 3ddc8b84) 
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/platform_device.h>
37 
38 #include <asm/mc146818rtc.h>
39 #include <asm/oplib.h>
40 #include <asm/timex.h>
41 #include <asm/timer.h>
42 #include <asm/irq.h>
43 #include <asm/io.h>
44 #include <asm/idprom.h>
45 #include <asm/page.h>
46 #include <asm/pcic.h>
47 #include <asm/irq_regs.h>
48 #include <asm/setup.h>
49 
50 #include "kernel.h"
51 #include "irq.h"
52 
53 static __cacheline_aligned_in_smp DEFINE_SEQLOCK(timer_cs_lock);
54 static __volatile__ u64 timer_cs_internal_counter = 0;
55 static char timer_cs_enabled = 0;
56 
57 static struct clock_event_device timer_ce;
58 static char timer_ce_enabled = 0;
59 
60 #ifdef CONFIG_SMP
61 DEFINE_PER_CPU(struct clock_event_device, sparc32_clockevent);
62 #endif
63 
64 DEFINE_SPINLOCK(rtc_lock);
65 EXPORT_SYMBOL(rtc_lock);
66 
67 unsigned long profile_pc(struct pt_regs *regs)
68 {
69 	extern char __copy_user_begin[], __copy_user_end[];
70 	extern char __bzero_begin[], __bzero_end[];
71 
72 	unsigned long pc = regs->pc;
73 
74 	if (in_lock_functions(pc) ||
75 	    (pc >= (unsigned long) __copy_user_begin &&
76 	     pc < (unsigned long) __copy_user_end) ||
77 	    (pc >= (unsigned long) __bzero_begin &&
78 	     pc < (unsigned long) __bzero_end))
79 		pc = regs->u_regs[UREG_RETPC];
80 	return pc;
81 }
82 
83 EXPORT_SYMBOL(profile_pc);
84 
85 volatile u32 __iomem *master_l10_counter;
86 
87 irqreturn_t notrace timer_interrupt(int dummy, void *dev_id)
88 {
89 	if (timer_cs_enabled) {
90 		write_seqlock(&timer_cs_lock);
91 		timer_cs_internal_counter++;
92 		sparc_config.clear_clock_irq();
93 		write_sequnlock(&timer_cs_lock);
94 	} else {
95 		sparc_config.clear_clock_irq();
96 	}
97 
98 	if (timer_ce_enabled)
99 		timer_ce.event_handler(&timer_ce);
100 
101 	return IRQ_HANDLED;
102 }
103 
104 static int timer_ce_shutdown(struct clock_event_device *evt)
105 {
106 	timer_ce_enabled = 0;
107 	smp_mb();
108 	return 0;
109 }
110 
111 static int timer_ce_set_periodic(struct clock_event_device *evt)
112 {
113 	timer_ce_enabled = 1;
114 	smp_mb();
115 	return 0;
116 }
117 
118 static __init void setup_timer_ce(void)
119 {
120 	struct clock_event_device *ce = &timer_ce;
121 
122 	BUG_ON(smp_processor_id() != boot_cpu_id);
123 
124 	ce->name     = "timer_ce";
125 	ce->rating   = 100;
126 	ce->features = CLOCK_EVT_FEAT_PERIODIC;
127 	ce->set_state_shutdown = timer_ce_shutdown;
128 	ce->set_state_periodic = timer_ce_set_periodic;
129 	ce->tick_resume = timer_ce_set_periodic;
130 	ce->cpumask  = cpu_possible_mask;
131 	ce->shift    = 32;
132 	ce->mult     = div_sc(sparc_config.clock_rate, NSEC_PER_SEC,
133 	                      ce->shift);
134 	clockevents_register_device(ce);
135 }
136 
137 static unsigned int sbus_cycles_offset(void)
138 {
139 	u32 val, offset;
140 
141 	val = sbus_readl(master_l10_counter);
142 	offset = (val >> TIMER_VALUE_SHIFT) & TIMER_VALUE_MASK;
143 
144 	/* Limit hit? */
145 	if (val & TIMER_LIMIT_BIT)
146 		offset += sparc_config.cs_period;
147 
148 	return offset;
149 }
150 
151 static u64 timer_cs_read(struct clocksource *cs)
152 {
153 	unsigned int seq, offset;
154 	u64 cycles;
155 
156 	do {
157 		seq = read_seqbegin(&timer_cs_lock);
158 
159 		cycles = timer_cs_internal_counter;
160 		offset = sparc_config.get_cycles_offset();
161 	} while (read_seqretry(&timer_cs_lock, seq));
162 
163 	/* Count absolute cycles */
164 	cycles *= sparc_config.cs_period;
165 	cycles += offset;
166 
167 	return cycles;
168 }
169 
170 static struct clocksource timer_cs = {
171 	.name	= "timer_cs",
172 	.rating	= 100,
173 	.read	= timer_cs_read,
174 	.mask	= CLOCKSOURCE_MASK(64),
175 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
176 };
177 
178 static __init int setup_timer_cs(void)
179 {
180 	timer_cs_enabled = 1;
181 	return clocksource_register_hz(&timer_cs, sparc_config.clock_rate);
182 }
183 
184 #ifdef CONFIG_SMP
185 static int percpu_ce_shutdown(struct clock_event_device *evt)
186 {
187 	int cpu = cpumask_first(evt->cpumask);
188 
189 	sparc_config.load_profile_irq(cpu, 0);
190 	return 0;
191 }
192 
193 static int percpu_ce_set_periodic(struct clock_event_device *evt)
194 {
195 	int cpu = cpumask_first(evt->cpumask);
196 
197 	sparc_config.load_profile_irq(cpu, SBUS_CLOCK_RATE / HZ);
198 	return 0;
199 }
200 
201 static int percpu_ce_set_next_event(unsigned long delta,
202 				    struct clock_event_device *evt)
203 {
204 	int cpu = cpumask_first(evt->cpumask);
205 	unsigned int next = (unsigned int)delta;
206 
207 	sparc_config.load_profile_irq(cpu, next);
208 	return 0;
209 }
210 
211 void register_percpu_ce(int cpu)
212 {
213 	struct clock_event_device *ce = &per_cpu(sparc32_clockevent, cpu);
214 	unsigned int features = CLOCK_EVT_FEAT_PERIODIC;
215 
216 	if (sparc_config.features & FEAT_L14_ONESHOT)
217 		features |= CLOCK_EVT_FEAT_ONESHOT;
218 
219 	ce->name           = "percpu_ce";
220 	ce->rating         = 200;
221 	ce->features       = features;
222 	ce->set_state_shutdown = percpu_ce_shutdown;
223 	ce->set_state_periodic = percpu_ce_set_periodic;
224 	ce->set_state_oneshot = percpu_ce_shutdown;
225 	ce->set_next_event = percpu_ce_set_next_event;
226 	ce->cpumask        = cpumask_of(cpu);
227 	ce->shift          = 32;
228 	ce->mult           = div_sc(sparc_config.clock_rate, NSEC_PER_SEC,
229 	                            ce->shift);
230 	ce->max_delta_ns   = clockevent_delta2ns(sparc_config.clock_rate, ce);
231 	ce->max_delta_ticks = (unsigned long)sparc_config.clock_rate;
232 	ce->min_delta_ns   = clockevent_delta2ns(100, ce);
233 	ce->min_delta_ticks = 100;
234 
235 	clockevents_register_device(ce);
236 }
237 #endif
238 
239 static unsigned char mostek_read_byte(struct device *dev, u32 ofs)
240 {
241 	struct platform_device *pdev = to_platform_device(dev);
242 	struct m48t59_plat_data *pdata = pdev->dev.platform_data;
243 
244 	return readb(pdata->ioaddr + ofs);
245 }
246 
247 static void mostek_write_byte(struct device *dev, u32 ofs, u8 val)
248 {
249 	struct platform_device *pdev = to_platform_device(dev);
250 	struct m48t59_plat_data *pdata = pdev->dev.platform_data;
251 
252 	writeb(val, pdata->ioaddr + ofs);
253 }
254 
255 static struct m48t59_plat_data m48t59_data = {
256 	.read_byte = mostek_read_byte,
257 	.write_byte = mostek_write_byte,
258 };
259 
260 /* resource is set at runtime */
261 static struct platform_device m48t59_rtc = {
262 	.name		= "rtc-m48t59",
263 	.id		= 0,
264 	.num_resources	= 1,
265 	.dev	= {
266 		.platform_data = &m48t59_data,
267 	},
268 };
269 
270 static int clock_probe(struct platform_device *op)
271 {
272 	struct device_node *dp = op->dev.of_node;
273 	const char *model = of_get_property(dp, "model", NULL);
274 
275 	if (!model)
276 		return -ENODEV;
277 
278 	/* Only the primary RTC has an address property */
279 	if (!of_property_present(dp, "address"))
280 		return -ENODEV;
281 
282 	m48t59_rtc.resource = &op->resource[0];
283 	if (!strcmp(model, "mk48t02")) {
284 		/* Map the clock register io area read-only */
285 		m48t59_data.ioaddr = of_ioremap(&op->resource[0], 0,
286 						2048, "rtc-m48t59");
287 		m48t59_data.type = M48T59RTC_TYPE_M48T02;
288 	} else if (!strcmp(model, "mk48t08")) {
289 		m48t59_data.ioaddr = of_ioremap(&op->resource[0], 0,
290 						8192, "rtc-m48t59");
291 		m48t59_data.type = M48T59RTC_TYPE_M48T08;
292 	} else
293 		return -ENODEV;
294 
295 	if (platform_device_register(&m48t59_rtc) < 0)
296 		printk(KERN_ERR "Registering RTC device failed\n");
297 
298 	return 0;
299 }
300 
301 static const struct of_device_id clock_match[] = {
302 	{
303 		.name = "eeprom",
304 	},
305 	{},
306 };
307 
308 static struct platform_driver clock_driver = {
309 	.probe		= clock_probe,
310 	.driver = {
311 		.name = "rtc",
312 		.of_match_table = clock_match,
313 	},
314 };
315 
316 
317 /* Probe for the mostek real time clock chip. */
318 static int __init clock_init(void)
319 {
320 	return platform_driver_register(&clock_driver);
321 }
322 /* Must be after subsys_initcall() so that busses are probed.  Must
323  * be before device_initcall() because things like the RTC driver
324  * need to see the clock registers.
325  */
326 fs_initcall(clock_init);
327 
328 static void __init sparc32_late_time_init(void)
329 {
330 	if (sparc_config.features & FEAT_L10_CLOCKEVENT)
331 		setup_timer_ce();
332 	if (sparc_config.features & FEAT_L10_CLOCKSOURCE)
333 		setup_timer_cs();
334 #ifdef CONFIG_SMP
335 	register_percpu_ce(smp_processor_id());
336 #endif
337 }
338 
339 static void __init sbus_time_init(void)
340 {
341 	sparc_config.get_cycles_offset = sbus_cycles_offset;
342 	sparc_config.init_timers();
343 }
344 
345 void __init time_init(void)
346 {
347 	sparc_config.features = 0;
348 	late_time_init = sparc32_late_time_init;
349 
350 	if (pcic_present())
351 		pci_time_init();
352 	else
353 		sbus_time_init();
354 }
355 
356