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1/*
2 * linux/arch/arm/mach-omap2/timer.c
3 *
4 * OMAP2 GP timer support.
5 *
6 * Copyright (C) 2009 Nokia Corporation
7 *
8 * Update to use new clocksource/clockevent layers
9 * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
10 * Copyright (C) 2007 MontaVista Software, Inc.
11 *
12 * Original driver:
13 * Copyright (C) 2005 Nokia Corporation
14 * Author: Paul Mundt <paul.mundt@nokia.com>
15 * Juha Yrjölä <juha.yrjola@nokia.com>
16 * OMAP Dual-mode timer framework support by Timo Teras
17 *
18 * Some parts based off of TI's 24xx code:
19 *
20 * Copyright (C) 2004-2009 Texas Instruments, Inc.
21 *
22 * Roughly modelled after the OMAP1 MPU timer code.
23 * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
24 *
25 * This file is subject to the terms and conditions of the GNU General Public
26 * License. See the file "COPYING" in the main directory of this archive
27 * for more details.
28 */
29#include <linux/clk.h>
30#include <linux/clocksource.h>
31
32#include "soc.h"
33#include "common.h"
34#include "control.h"
35#include "omap-secure.h"
36
37#define REALTIME_COUNTER_BASE 0x48243200
38#define INCREMENTER_NUMERATOR_OFFSET 0x10
39#define INCREMENTER_DENUMERATOR_RELOAD_OFFSET 0x14
40#define NUMERATOR_DENUMERATOR_MASK 0xfffff000
41
42static unsigned long arch_timer_freq;
43
44void set_cntfreq(void)
45{
46 omap_smc1(OMAP5_DRA7_MON_SET_CNTFRQ_INDEX, arch_timer_freq);
47}
48
49/*
50 * The realtime counter also called master counter, is a free-running
51 * counter, which is related to real time. It produces the count used
52 * by the CPU local timer peripherals in the MPU cluster. The timer counts
53 * at a rate of 6.144 MHz. Because the device operates on different clocks
54 * in different power modes, the master counter shifts operation between
55 * clocks, adjusting the increment per clock in hardware accordingly to
56 * maintain a constant count rate.
57 */
58static void __init realtime_counter_init(void)
59{
60 void __iomem *base;
61 static struct clk *sys_clk;
62 unsigned long rate;
63 unsigned int reg;
64 unsigned long long num, den;
65
66 base = ioremap(REALTIME_COUNTER_BASE, SZ_32);
67 if (!base) {
68 pr_err("%s: ioremap failed\n", __func__);
69 return;
70 }
71 sys_clk = clk_get(NULL, "sys_clkin");
72 if (IS_ERR(sys_clk)) {
73 pr_err("%s: failed to get system clock handle\n", __func__);
74 iounmap(base);
75 return;
76 }
77
78 rate = clk_get_rate(sys_clk);
79 clk_put(sys_clk);
80
81 if (soc_is_dra7xx()) {
82 /*
83 * Errata i856 says the 32.768KHz crystal does not start at
84 * power on, so the CPU falls back to an emulated 32KHz clock
85 * based on sysclk / 610 instead. This causes the master counter
86 * frequency to not be 6.144MHz but at sysclk / 610 * 375 / 2
87 * (OR sysclk * 75 / 244)
88 *
89 * This affects at least the DRA7/AM572x 1.0, 1.1 revisions.
90 * Of course any board built without a populated 32.768KHz
91 * crystal would also need this fix even if the CPU is fixed
92 * later.
93 *
94 * Either case can be detected by using the two speedselect bits
95 * If they are not 0, then the 32.768KHz clock driving the
96 * coarse counter that corrects the fine counter every time it
97 * ticks is actually rate/610 rather than 32.768KHz and we
98 * should compensate to avoid the 570ppm (at 20MHz, much worse
99 * at other rates) too fast system time.
100 */
101 reg = omap_ctrl_readl(DRA7_CTRL_CORE_BOOTSTRAP);
102 if (reg & DRA7_SPEEDSELECT_MASK) {
103 num = 75;
104 den = 244;
105 goto sysclk1_based;
106 }
107 }
108
109 /* Numerator/denumerator values refer TRM Realtime Counter section */
110 switch (rate) {
111 case 12000000:
112 num = 64;
113 den = 125;
114 break;
115 case 13000000:
116 num = 768;
117 den = 1625;
118 break;
119 case 19200000:
120 num = 8;
121 den = 25;
122 break;
123 case 20000000:
124 num = 192;
125 den = 625;
126 break;
127 case 26000000:
128 num = 384;
129 den = 1625;
130 break;
131 case 27000000:
132 num = 256;
133 den = 1125;
134 break;
135 case 38400000:
136 default:
137 /* Program it for 38.4 MHz */
138 num = 4;
139 den = 25;
140 break;
141 }
142
143sysclk1_based:
144 /* Program numerator and denumerator registers */
145 reg = readl_relaxed(base + INCREMENTER_NUMERATOR_OFFSET) &
146 NUMERATOR_DENUMERATOR_MASK;
147 reg |= num;
148 writel_relaxed(reg, base + INCREMENTER_NUMERATOR_OFFSET);
149
150 reg = readl_relaxed(base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET) &
151 NUMERATOR_DENUMERATOR_MASK;
152 reg |= den;
153 writel_relaxed(reg, base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET);
154
155 arch_timer_freq = DIV_ROUND_UP_ULL(rate * num, den);
156 set_cntfreq();
157
158 iounmap(base);
159}
160
161void __init omap5_realtime_timer_init(void)
162{
163 omap_clk_init();
164 realtime_counter_init();
165
166 timer_probe();
167}
1/*
2 * linux/arch/arm/mach-omap2/timer.c
3 *
4 * OMAP2 GP timer support.
5 *
6 * Copyright (C) 2009 Nokia Corporation
7 *
8 * Update to use new clocksource/clockevent layers
9 * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
10 * Copyright (C) 2007 MontaVista Software, Inc.
11 *
12 * Original driver:
13 * Copyright (C) 2005 Nokia Corporation
14 * Author: Paul Mundt <paul.mundt@nokia.com>
15 * Juha Yrjölä <juha.yrjola@nokia.com>
16 * OMAP Dual-mode timer framework support by Timo Teras
17 *
18 * Some parts based off of TI's 24xx code:
19 *
20 * Copyright (C) 2004-2009 Texas Instruments, Inc.
21 *
22 * Roughly modelled after the OMAP1 MPU timer code.
23 * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
24 *
25 * This file is subject to the terms and conditions of the GNU General Public
26 * License. See the file "COPYING" in the main directory of this archive
27 * for more details.
28 */
29#include <linux/init.h>
30#include <linux/time.h>
31#include <linux/interrupt.h>
32#include <linux/err.h>
33#include <linux/clk.h>
34#include <linux/delay.h>
35#include <linux/irq.h>
36#include <linux/clocksource.h>
37#include <linux/clockchips.h>
38#include <linux/slab.h>
39#include <linux/of.h>
40#include <linux/of_address.h>
41#include <linux/of_irq.h>
42#include <linux/platform_device.h>
43#include <linux/platform_data/dmtimer-omap.h>
44#include <linux/sched_clock.h>
45
46#include <asm/mach/time.h>
47#include <asm/smp_twd.h>
48
49#include "omap_hwmod.h"
50#include "omap_device.h"
51#include <plat/counter-32k.h>
52#include <plat/dmtimer.h>
53#include "omap-pm.h"
54
55#include "soc.h"
56#include "common.h"
57#include "control.h"
58#include "powerdomain.h"
59#include "omap-secure.h"
60
61#define REALTIME_COUNTER_BASE 0x48243200
62#define INCREMENTER_NUMERATOR_OFFSET 0x10
63#define INCREMENTER_DENUMERATOR_RELOAD_OFFSET 0x14
64#define NUMERATOR_DENUMERATOR_MASK 0xfffff000
65
66/* Clockevent code */
67
68static struct omap_dm_timer clkev;
69static struct clock_event_device clockevent_gpt;
70
71#ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
72static unsigned long arch_timer_freq;
73
74void set_cntfreq(void)
75{
76 omap_smc1(OMAP5_DRA7_MON_SET_CNTFRQ_INDEX, arch_timer_freq);
77}
78#endif
79
80static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
81{
82 struct clock_event_device *evt = &clockevent_gpt;
83
84 __omap_dm_timer_write_status(&clkev, OMAP_TIMER_INT_OVERFLOW);
85
86 evt->event_handler(evt);
87 return IRQ_HANDLED;
88}
89
90static struct irqaction omap2_gp_timer_irq = {
91 .name = "gp_timer",
92 .flags = IRQF_TIMER | IRQF_IRQPOLL,
93 .handler = omap2_gp_timer_interrupt,
94};
95
96static int omap2_gp_timer_set_next_event(unsigned long cycles,
97 struct clock_event_device *evt)
98{
99 __omap_dm_timer_load_start(&clkev, OMAP_TIMER_CTRL_ST,
100 0xffffffff - cycles, OMAP_TIMER_POSTED);
101
102 return 0;
103}
104
105static int omap2_gp_timer_shutdown(struct clock_event_device *evt)
106{
107 __omap_dm_timer_stop(&clkev, OMAP_TIMER_POSTED, clkev.rate);
108 return 0;
109}
110
111static int omap2_gp_timer_set_periodic(struct clock_event_device *evt)
112{
113 u32 period;
114
115 __omap_dm_timer_stop(&clkev, OMAP_TIMER_POSTED, clkev.rate);
116
117 period = clkev.rate / HZ;
118 period -= 1;
119 /* Looks like we need to first set the load value separately */
120 __omap_dm_timer_write(&clkev, OMAP_TIMER_LOAD_REG, 0xffffffff - period,
121 OMAP_TIMER_POSTED);
122 __omap_dm_timer_load_start(&clkev,
123 OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST,
124 0xffffffff - period, OMAP_TIMER_POSTED);
125 return 0;
126}
127
128static struct clock_event_device clockevent_gpt = {
129 .features = CLOCK_EVT_FEAT_PERIODIC |
130 CLOCK_EVT_FEAT_ONESHOT,
131 .rating = 300,
132 .set_next_event = omap2_gp_timer_set_next_event,
133 .set_state_shutdown = omap2_gp_timer_shutdown,
134 .set_state_periodic = omap2_gp_timer_set_periodic,
135 .set_state_oneshot = omap2_gp_timer_shutdown,
136 .tick_resume = omap2_gp_timer_shutdown,
137};
138
139static struct property device_disabled = {
140 .name = "status",
141 .length = sizeof("disabled"),
142 .value = "disabled",
143};
144
145static const struct of_device_id omap_timer_match[] __initconst = {
146 { .compatible = "ti,omap2420-timer", },
147 { .compatible = "ti,omap3430-timer", },
148 { .compatible = "ti,omap4430-timer", },
149 { .compatible = "ti,omap5430-timer", },
150 { .compatible = "ti,dm814-timer", },
151 { .compatible = "ti,dm816-timer", },
152 { .compatible = "ti,am335x-timer", },
153 { .compatible = "ti,am335x-timer-1ms", },
154 { }
155};
156
157/**
158 * omap_get_timer_dt - get a timer using device-tree
159 * @match - device-tree match structure for matching a device type
160 * @property - optional timer property to match
161 *
162 * Helper function to get a timer during early boot using device-tree for use
163 * as kernel system timer. Optionally, the property argument can be used to
164 * select a timer with a specific property. Once a timer is found then mark
165 * the timer node in device-tree as disabled, to prevent the kernel from
166 * registering this timer as a platform device and so no one else can use it.
167 */
168static struct device_node * __init omap_get_timer_dt(const struct of_device_id *match,
169 const char *property)
170{
171 struct device_node *np;
172
173 for_each_matching_node(np, match) {
174 if (!of_device_is_available(np))
175 continue;
176
177 if (property && !of_get_property(np, property, NULL))
178 continue;
179
180 if (!property && (of_get_property(np, "ti,timer-alwon", NULL) ||
181 of_get_property(np, "ti,timer-dsp", NULL) ||
182 of_get_property(np, "ti,timer-pwm", NULL) ||
183 of_get_property(np, "ti,timer-secure", NULL)))
184 continue;
185
186 if (!of_device_is_compatible(np, "ti,omap-counter32k"))
187 of_add_property(np, &device_disabled);
188 return np;
189 }
190
191 return NULL;
192}
193
194/**
195 * omap_dmtimer_init - initialisation function when device tree is used
196 *
197 * For secure OMAP3/DRA7xx devices, timers with device type "timer-secure"
198 * cannot be used by the kernel as they are reserved. Therefore, to prevent the
199 * kernel registering these devices remove them dynamically from the device
200 * tree on boot.
201 */
202static void __init omap_dmtimer_init(void)
203{
204 struct device_node *np;
205
206 if (!cpu_is_omap34xx() && !soc_is_dra7xx())
207 return;
208
209 /* If we are a secure device, remove any secure timer nodes */
210 if ((omap_type() != OMAP2_DEVICE_TYPE_GP)) {
211 np = omap_get_timer_dt(omap_timer_match, "ti,timer-secure");
212 of_node_put(np);
213 }
214}
215
216/**
217 * omap_dm_timer_get_errata - get errata flags for a timer
218 *
219 * Get the timer errata flags that are specific to the OMAP device being used.
220 */
221static u32 __init omap_dm_timer_get_errata(void)
222{
223 if (cpu_is_omap24xx())
224 return 0;
225
226 return OMAP_TIMER_ERRATA_I103_I767;
227}
228
229static int __init omap_dm_timer_init_one(struct omap_dm_timer *timer,
230 const char *fck_source,
231 const char *property,
232 const char **timer_name,
233 int posted)
234{
235 char name[10]; /* 10 = sizeof("gptXX_Xck0") */
236 const char *oh_name = NULL;
237 struct device_node *np;
238 struct omap_hwmod *oh;
239 struct resource irq, mem;
240 struct clk *src;
241 int r = 0;
242
243 if (of_have_populated_dt()) {
244 np = omap_get_timer_dt(omap_timer_match, property);
245 if (!np)
246 return -ENODEV;
247
248 of_property_read_string_index(np, "ti,hwmods", 0, &oh_name);
249 if (!oh_name)
250 return -ENODEV;
251
252 timer->irq = irq_of_parse_and_map(np, 0);
253 if (!timer->irq)
254 return -ENXIO;
255
256 timer->io_base = of_iomap(np, 0);
257
258 of_node_put(np);
259 } else {
260 if (omap_dm_timer_reserve_systimer(timer->id))
261 return -ENODEV;
262
263 sprintf(name, "timer%d", timer->id);
264 oh_name = name;
265 }
266
267 oh = omap_hwmod_lookup(oh_name);
268 if (!oh)
269 return -ENODEV;
270
271 *timer_name = oh->name;
272
273 if (!of_have_populated_dt()) {
274 r = omap_hwmod_get_resource_byname(oh, IORESOURCE_IRQ, NULL,
275 &irq);
276 if (r)
277 return -ENXIO;
278 timer->irq = irq.start;
279
280 r = omap_hwmod_get_resource_byname(oh, IORESOURCE_MEM, NULL,
281 &mem);
282 if (r)
283 return -ENXIO;
284
285 /* Static mapping, never released */
286 timer->io_base = ioremap(mem.start, mem.end - mem.start);
287 }
288
289 if (!timer->io_base)
290 return -ENXIO;
291
292 omap_hwmod_setup_one(oh_name);
293
294 /* After the dmtimer is using hwmod these clocks won't be needed */
295 timer->fclk = clk_get(NULL, omap_hwmod_get_main_clk(oh));
296 if (IS_ERR(timer->fclk))
297 return PTR_ERR(timer->fclk);
298
299 src = clk_get(NULL, fck_source);
300 if (IS_ERR(src))
301 return PTR_ERR(src);
302
303 WARN(clk_set_parent(timer->fclk, src) < 0,
304 "Cannot set timer parent clock, no PLL clock driver?");
305
306 clk_put(src);
307
308 omap_hwmod_enable(oh);
309 __omap_dm_timer_init_regs(timer);
310
311 if (posted)
312 __omap_dm_timer_enable_posted(timer);
313
314 /* Check that the intended posted configuration matches the actual */
315 if (posted != timer->posted)
316 return -EINVAL;
317
318 timer->rate = clk_get_rate(timer->fclk);
319 timer->reserved = 1;
320
321 return r;
322}
323
324#if !defined(CONFIG_SMP) && defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)
325void tick_broadcast(const struct cpumask *mask)
326{
327}
328#endif
329
330static void __init omap2_gp_clockevent_init(int gptimer_id,
331 const char *fck_source,
332 const char *property)
333{
334 int res;
335
336 clkev.id = gptimer_id;
337 clkev.errata = omap_dm_timer_get_errata();
338
339 /*
340 * For clock-event timers we never read the timer counter and
341 * so we are not impacted by errata i103 and i767. Therefore,
342 * we can safely ignore this errata for clock-event timers.
343 */
344 __omap_dm_timer_override_errata(&clkev, OMAP_TIMER_ERRATA_I103_I767);
345
346 res = omap_dm_timer_init_one(&clkev, fck_source, property,
347 &clockevent_gpt.name, OMAP_TIMER_POSTED);
348 BUG_ON(res);
349
350 omap2_gp_timer_irq.dev_id = &clkev;
351 setup_irq(clkev.irq, &omap2_gp_timer_irq);
352
353 __omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);
354
355 clockevent_gpt.cpumask = cpu_possible_mask;
356 clockevent_gpt.irq = omap_dm_timer_get_irq(&clkev);
357 clockevents_config_and_register(&clockevent_gpt, clkev.rate,
358 3, /* Timer internal resynch latency */
359 0xffffffff);
360
361 pr_info("OMAP clockevent source: %s at %lu Hz\n", clockevent_gpt.name,
362 clkev.rate);
363}
364
365/* Clocksource code */
366static struct omap_dm_timer clksrc;
367static bool use_gptimer_clksrc __initdata;
368
369/*
370 * clocksource
371 */
372static u64 clocksource_read_cycles(struct clocksource *cs)
373{
374 return (u64)__omap_dm_timer_read_counter(&clksrc,
375 OMAP_TIMER_NONPOSTED);
376}
377
378static struct clocksource clocksource_gpt = {
379 .rating = 300,
380 .read = clocksource_read_cycles,
381 .mask = CLOCKSOURCE_MASK(32),
382 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
383};
384
385static u64 notrace dmtimer_read_sched_clock(void)
386{
387 if (clksrc.reserved)
388 return __omap_dm_timer_read_counter(&clksrc,
389 OMAP_TIMER_NONPOSTED);
390
391 return 0;
392}
393
394static const struct of_device_id omap_counter_match[] __initconst = {
395 { .compatible = "ti,omap-counter32k", },
396 { }
397};
398
399/* Setup free-running counter for clocksource */
400static int __init __maybe_unused omap2_sync32k_clocksource_init(void)
401{
402 int ret;
403 struct device_node *np = NULL;
404 struct omap_hwmod *oh;
405 const char *oh_name = "counter_32k";
406
407 /*
408 * If device-tree is present, then search the DT blob
409 * to see if the 32kHz counter is supported.
410 */
411 if (of_have_populated_dt()) {
412 np = omap_get_timer_dt(omap_counter_match, NULL);
413 if (!np)
414 return -ENODEV;
415
416 of_property_read_string_index(np, "ti,hwmods", 0, &oh_name);
417 if (!oh_name)
418 return -ENODEV;
419 }
420
421 /*
422 * First check hwmod data is available for sync32k counter
423 */
424 oh = omap_hwmod_lookup(oh_name);
425 if (!oh || oh->slaves_cnt == 0)
426 return -ENODEV;
427
428 omap_hwmod_setup_one(oh_name);
429
430 ret = omap_hwmod_enable(oh);
431 if (ret) {
432 pr_warn("%s: failed to enable counter_32k module (%d)\n",
433 __func__, ret);
434 return ret;
435 }
436
437 if (!of_have_populated_dt()) {
438 void __iomem *vbase;
439
440 vbase = omap_hwmod_get_mpu_rt_va(oh);
441
442 ret = omap_init_clocksource_32k(vbase);
443 if (ret) {
444 pr_warn("%s: failed to initialize counter_32k as a clocksource (%d)\n",
445 __func__, ret);
446 omap_hwmod_idle(oh);
447 }
448 }
449 return ret;
450}
451
452static void __init omap2_gptimer_clocksource_init(int gptimer_id,
453 const char *fck_source,
454 const char *property)
455{
456 int res;
457
458 clksrc.id = gptimer_id;
459 clksrc.errata = omap_dm_timer_get_errata();
460
461 res = omap_dm_timer_init_one(&clksrc, fck_source, property,
462 &clocksource_gpt.name,
463 OMAP_TIMER_NONPOSTED);
464 BUG_ON(res);
465
466 __omap_dm_timer_load_start(&clksrc,
467 OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0,
468 OMAP_TIMER_NONPOSTED);
469 sched_clock_register(dmtimer_read_sched_clock, 32, clksrc.rate);
470
471 if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
472 pr_err("Could not register clocksource %s\n",
473 clocksource_gpt.name);
474 else
475 pr_info("OMAP clocksource: %s at %lu Hz\n",
476 clocksource_gpt.name, clksrc.rate);
477}
478
479static void __init __omap_sync32k_timer_init(int clkev_nr, const char *clkev_src,
480 const char *clkev_prop, int clksrc_nr, const char *clksrc_src,
481 const char *clksrc_prop, bool gptimer)
482{
483 omap_clk_init();
484 omap_dmtimer_init();
485 omap2_gp_clockevent_init(clkev_nr, clkev_src, clkev_prop);
486
487 /* Enable the use of clocksource="gp_timer" kernel parameter */
488 if (use_gptimer_clksrc || gptimer)
489 omap2_gptimer_clocksource_init(clksrc_nr, clksrc_src,
490 clksrc_prop);
491 else
492 omap2_sync32k_clocksource_init();
493}
494
495void __init omap_init_time(void)
496{
497 __omap_sync32k_timer_init(1, "timer_32k_ck", "ti,timer-alwon",
498 2, "timer_sys_ck", NULL, false);
499
500 clocksource_probe();
501}
502
503#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM43XX)
504void __init omap3_secure_sync32k_timer_init(void)
505{
506 __omap_sync32k_timer_init(12, "secure_32k_fck", "ti,timer-secure",
507 2, "timer_sys_ck", NULL, false);
508
509 clocksource_probe();
510}
511#endif /* CONFIG_ARCH_OMAP3 */
512
513#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) || \
514 defined(CONFIG_SOC_AM43XX)
515void __init omap3_gptimer_timer_init(void)
516{
517 __omap_sync32k_timer_init(2, "timer_sys_ck", NULL,
518 1, "timer_sys_ck", "ti,timer-alwon", true);
519 if (of_have_populated_dt())
520 clocksource_probe();
521}
522#endif
523
524#if defined(CONFIG_ARCH_OMAP4) || defined(CONFIG_SOC_OMAP5) || \
525 defined(CONFIG_SOC_DRA7XX)
526static void __init omap4_sync32k_timer_init(void)
527{
528 __omap_sync32k_timer_init(1, "timer_32k_ck", "ti,timer-alwon",
529 2, "sys_clkin_ck", NULL, false);
530}
531
532void __init omap4_local_timer_init(void)
533{
534 omap4_sync32k_timer_init();
535 clocksource_probe();
536}
537#endif
538
539#if defined(CONFIG_SOC_OMAP5) || defined(CONFIG_SOC_DRA7XX)
540
541/*
542 * The realtime counter also called master counter, is a free-running
543 * counter, which is related to real time. It produces the count used
544 * by the CPU local timer peripherals in the MPU cluster. The timer counts
545 * at a rate of 6.144 MHz. Because the device operates on different clocks
546 * in different power modes, the master counter shifts operation between
547 * clocks, adjusting the increment per clock in hardware accordingly to
548 * maintain a constant count rate.
549 */
550static void __init realtime_counter_init(void)
551{
552#ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
553 void __iomem *base;
554 static struct clk *sys_clk;
555 unsigned long rate;
556 unsigned int reg;
557 unsigned long long num, den;
558
559 base = ioremap(REALTIME_COUNTER_BASE, SZ_32);
560 if (!base) {
561 pr_err("%s: ioremap failed\n", __func__);
562 return;
563 }
564 sys_clk = clk_get(NULL, "sys_clkin");
565 if (IS_ERR(sys_clk)) {
566 pr_err("%s: failed to get system clock handle\n", __func__);
567 iounmap(base);
568 return;
569 }
570
571 rate = clk_get_rate(sys_clk);
572
573 if (soc_is_dra7xx()) {
574 /*
575 * Errata i856 says the 32.768KHz crystal does not start at
576 * power on, so the CPU falls back to an emulated 32KHz clock
577 * based on sysclk / 610 instead. This causes the master counter
578 * frequency to not be 6.144MHz but at sysclk / 610 * 375 / 2
579 * (OR sysclk * 75 / 244)
580 *
581 * This affects at least the DRA7/AM572x 1.0, 1.1 revisions.
582 * Of course any board built without a populated 32.768KHz
583 * crystal would also need this fix even if the CPU is fixed
584 * later.
585 *
586 * Either case can be detected by using the two speedselect bits
587 * If they are not 0, then the 32.768KHz clock driving the
588 * coarse counter that corrects the fine counter every time it
589 * ticks is actually rate/610 rather than 32.768KHz and we
590 * should compensate to avoid the 570ppm (at 20MHz, much worse
591 * at other rates) too fast system time.
592 */
593 reg = omap_ctrl_readl(DRA7_CTRL_CORE_BOOTSTRAP);
594 if (reg & DRA7_SPEEDSELECT_MASK) {
595 num = 75;
596 den = 244;
597 goto sysclk1_based;
598 }
599 }
600
601 /* Numerator/denumerator values refer TRM Realtime Counter section */
602 switch (rate) {
603 case 12000000:
604 num = 64;
605 den = 125;
606 break;
607 case 13000000:
608 num = 768;
609 den = 1625;
610 break;
611 case 19200000:
612 num = 8;
613 den = 25;
614 break;
615 case 20000000:
616 num = 192;
617 den = 625;
618 break;
619 case 26000000:
620 num = 384;
621 den = 1625;
622 break;
623 case 27000000:
624 num = 256;
625 den = 1125;
626 break;
627 case 38400000:
628 default:
629 /* Program it for 38.4 MHz */
630 num = 4;
631 den = 25;
632 break;
633 }
634
635sysclk1_based:
636 /* Program numerator and denumerator registers */
637 reg = readl_relaxed(base + INCREMENTER_NUMERATOR_OFFSET) &
638 NUMERATOR_DENUMERATOR_MASK;
639 reg |= num;
640 writel_relaxed(reg, base + INCREMENTER_NUMERATOR_OFFSET);
641
642 reg = readl_relaxed(base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET) &
643 NUMERATOR_DENUMERATOR_MASK;
644 reg |= den;
645 writel_relaxed(reg, base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET);
646
647 arch_timer_freq = DIV_ROUND_UP_ULL(rate * num, den);
648 set_cntfreq();
649
650 iounmap(base);
651#endif
652}
653
654void __init omap5_realtime_timer_init(void)
655{
656 omap4_sync32k_timer_init();
657 realtime_counter_init();
658
659 clocksource_probe();
660}
661#endif /* CONFIG_SOC_OMAP5 || CONFIG_SOC_DRA7XX */
662
663/**
664 * omap_timer_init - build and register timer device with an
665 * associated timer hwmod
666 * @oh: timer hwmod pointer to be used to build timer device
667 * @user: parameter that can be passed from calling hwmod API
668 *
669 * Called by omap_hwmod_for_each_by_class to register each of the timer
670 * devices present in the system. The number of timer devices is known
671 * by parsing through the hwmod database for a given class name. At the
672 * end of function call memory is allocated for timer device and it is
673 * registered to the framework ready to be proved by the driver.
674 */
675static int __init omap_timer_init(struct omap_hwmod *oh, void *unused)
676{
677 int id;
678 int ret = 0;
679 char *name = "omap_timer";
680 struct dmtimer_platform_data *pdata;
681 struct platform_device *pdev;
682 struct omap_timer_capability_dev_attr *timer_dev_attr;
683
684 pr_debug("%s: %s\n", __func__, oh->name);
685
686 /* on secure device, do not register secure timer */
687 timer_dev_attr = oh->dev_attr;
688 if (omap_type() != OMAP2_DEVICE_TYPE_GP && timer_dev_attr)
689 if (timer_dev_attr->timer_capability == OMAP_TIMER_SECURE)
690 return ret;
691
692 pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
693 if (!pdata) {
694 pr_err("%s: No memory for [%s]\n", __func__, oh->name);
695 return -ENOMEM;
696 }
697
698 /*
699 * Extract the IDs from name field in hwmod database
700 * and use the same for constructing ids' for the
701 * timer devices. In a way, we are avoiding usage of
702 * static variable witin the function to do the same.
703 * CAUTION: We have to be careful and make sure the
704 * name in hwmod database does not change in which case
705 * we might either make corresponding change here or
706 * switch back static variable mechanism.
707 */
708 sscanf(oh->name, "timer%2d", &id);
709
710 if (timer_dev_attr)
711 pdata->timer_capability = timer_dev_attr->timer_capability;
712
713 pdata->timer_errata = omap_dm_timer_get_errata();
714 pdata->get_context_loss_count = omap_pm_get_dev_context_loss_count;
715
716 pdev = omap_device_build(name, id, oh, pdata, sizeof(*pdata));
717
718 if (IS_ERR(pdev)) {
719 pr_err("%s: Can't build omap_device for %s: %s.\n",
720 __func__, name, oh->name);
721 ret = -EINVAL;
722 }
723
724 kfree(pdata);
725
726 return ret;
727}
728
729/**
730 * omap2_dm_timer_init - top level regular device initialization
731 *
732 * Uses dedicated hwmod api to parse through hwmod database for
733 * given class name and then build and register the timer device.
734 */
735static int __init omap2_dm_timer_init(void)
736{
737 int ret;
738
739 /* If dtb is there, the devices will be created dynamically */
740 if (of_have_populated_dt())
741 return -ENODEV;
742
743 ret = omap_hwmod_for_each_by_class("timer", omap_timer_init, NULL);
744 if (unlikely(ret)) {
745 pr_err("%s: device registration failed.\n", __func__);
746 return -EINVAL;
747 }
748
749 return 0;
750}
751omap_arch_initcall(omap2_dm_timer_init);
752
753/**
754 * omap2_override_clocksource - clocksource override with user configuration
755 *
756 * Allows user to override default clocksource, using kernel parameter
757 * clocksource="gp_timer" (For all OMAP2PLUS architectures)
758 *
759 * Note that, here we are using same standard kernel parameter "clocksource=",
760 * and not introducing any OMAP specific interface.
761 */
762static int __init omap2_override_clocksource(char *str)
763{
764 if (!str)
765 return 0;
766 /*
767 * For OMAP architecture, we only have two options
768 * - sync_32k (default)
769 * - gp_timer (sys_clk based)
770 */
771 if (!strcmp(str, "gp_timer"))
772 use_gptimer_clksrc = true;
773
774 return 0;
775}
776early_param("clocksource", omap2_override_clocksource);