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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Time related functions for Hexagon architecture
4 *
5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
6 */
7
8#include <linux/init.h>
9#include <linux/delay.h>
10#include <linux/clockchips.h>
11#include <linux/clocksource.h>
12#include <linux/interrupt.h>
13#include <linux/err.h>
14#include <linux/platform_device.h>
15#include <linux/ioport.h>
16#include <linux/of.h>
17#include <linux/of_address.h>
18#include <linux/of_irq.h>
19#include <linux/module.h>
20
21#include <asm/hexagon_vm.h>
22#include <asm/time.h>
23
24#define TIMER_ENABLE BIT(0)
25
26/*
27 * For the clocksource we need:
28 * pcycle frequency (600MHz)
29 * For the loops_per_jiffy we need:
30 * thread/cpu frequency (100MHz)
31 * And for the timer, we need:
32 * sleep clock rate
33 */
34
35cycles_t pcycle_freq_mhz;
36cycles_t thread_freq_mhz;
37cycles_t sleep_clk_freq;
38
39/*
40 * 8x50 HDD Specs 5-8. Simulator co-sim not fixed until
41 * release 1.1, and then it's "adjustable" and probably not defaulted.
42 */
43#define RTOS_TIMER_INT 3
44#define RTOS_TIMER_REGS_ADDR 0xAB000000UL
45
46static struct resource rtos_timer_resources[] = {
47 {
48 .start = RTOS_TIMER_REGS_ADDR,
49 .end = RTOS_TIMER_REGS_ADDR+PAGE_SIZE-1,
50 .flags = IORESOURCE_MEM,
51 },
52};
53
54static struct platform_device rtos_timer_device = {
55 .name = "rtos_timer",
56 .id = -1,
57 .num_resources = ARRAY_SIZE(rtos_timer_resources),
58 .resource = rtos_timer_resources,
59};
60
61/* A lot of this stuff should move into a platform specific section. */
62struct adsp_hw_timer_struct {
63 u32 match; /* Match value */
64 u32 count;
65 u32 enable; /* [1] - CLR_ON_MATCH_EN, [0] - EN */
66 u32 clear; /* one-shot register that clears the count */
67};
68
69/* Look for "TCX0" for related constants. */
70static __iomem struct adsp_hw_timer_struct *rtos_timer;
71
72static u64 timer_get_cycles(struct clocksource *cs)
73{
74 return (u64) __vmgettime();
75}
76
77static struct clocksource hexagon_clocksource = {
78 .name = "pcycles",
79 .rating = 250,
80 .read = timer_get_cycles,
81 .mask = CLOCKSOURCE_MASK(64),
82 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
83};
84
85static int set_next_event(unsigned long delta, struct clock_event_device *evt)
86{
87 /* Assuming the timer will be disabled when we enter here. */
88
89 iowrite32(1, &rtos_timer->clear);
90 iowrite32(0, &rtos_timer->clear);
91
92 iowrite32(delta, &rtos_timer->match);
93 iowrite32(TIMER_ENABLE, &rtos_timer->enable);
94 return 0;
95}
96
97#ifdef CONFIG_SMP
98/* Broadcast mechanism */
99static void broadcast(const struct cpumask *mask)
100{
101 send_ipi(mask, IPI_TIMER);
102}
103#endif
104
105/* XXX Implement set_state_shutdown() */
106static struct clock_event_device hexagon_clockevent_dev = {
107 .name = "clockevent",
108 .features = CLOCK_EVT_FEAT_ONESHOT,
109 .rating = 400,
110 .irq = RTOS_TIMER_INT,
111 .set_next_event = set_next_event,
112#ifdef CONFIG_SMP
113 .broadcast = broadcast,
114#endif
115};
116
117#ifdef CONFIG_SMP
118static DEFINE_PER_CPU(struct clock_event_device, clock_events);
119
120void setup_percpu_clockdev(void)
121{
122 int cpu = smp_processor_id();
123 struct clock_event_device *ce_dev = &hexagon_clockevent_dev;
124 struct clock_event_device *dummy_clock_dev =
125 &per_cpu(clock_events, cpu);
126
127 memcpy(dummy_clock_dev, ce_dev, sizeof(*dummy_clock_dev));
128 INIT_LIST_HEAD(&dummy_clock_dev->list);
129
130 dummy_clock_dev->features = CLOCK_EVT_FEAT_DUMMY;
131 dummy_clock_dev->cpumask = cpumask_of(cpu);
132
133 clockevents_register_device(dummy_clock_dev);
134}
135
136/* Called from smp.c for each CPU's timer ipi call */
137void ipi_timer(void)
138{
139 int cpu = smp_processor_id();
140 struct clock_event_device *ce_dev = &per_cpu(clock_events, cpu);
141
142 ce_dev->event_handler(ce_dev);
143}
144#endif /* CONFIG_SMP */
145
146static irqreturn_t timer_interrupt(int irq, void *devid)
147{
148 struct clock_event_device *ce_dev = &hexagon_clockevent_dev;
149
150 iowrite32(0, &rtos_timer->enable);
151 ce_dev->event_handler(ce_dev);
152
153 return IRQ_HANDLED;
154}
155
156/*
157 * time_init_deferred - called by start_kernel to set up timer/clock source
158 *
159 * Install the IRQ handler for the clock, setup timers.
160 * This is done late, as that way, we can use ioremap().
161 *
162 * This runs just before the delay loop is calibrated, and
163 * is used for delay calibration.
164 */
165static void __init time_init_deferred(void)
166{
167 struct resource *resource = NULL;
168 struct clock_event_device *ce_dev = &hexagon_clockevent_dev;
169 unsigned long flag = IRQF_TIMER | IRQF_TRIGGER_RISING;
170
171 ce_dev->cpumask = cpu_all_mask;
172
173 resource = rtos_timer_device.resource;
174
175 /* ioremap here means this has to run later, after paging init */
176 rtos_timer = ioremap(resource->start, resource_size(resource));
177
178 if (!rtos_timer) {
179 release_mem_region(resource->start, resource_size(resource));
180 }
181 clocksource_register_khz(&hexagon_clocksource, pcycle_freq_mhz * 1000);
182
183 /* Note: the sim generic RTOS clock is apparently really 18750Hz */
184
185 /*
186 * Last arg is some guaranteed seconds for which the conversion will
187 * work without overflow.
188 */
189 clockevents_calc_mult_shift(ce_dev, sleep_clk_freq, 4);
190
191 ce_dev->max_delta_ns = clockevent_delta2ns(0x7fffffff, ce_dev);
192 ce_dev->max_delta_ticks = 0x7fffffff;
193 ce_dev->min_delta_ns = clockevent_delta2ns(0xf, ce_dev);
194 ce_dev->min_delta_ticks = 0xf;
195
196#ifdef CONFIG_SMP
197 setup_percpu_clockdev();
198#endif
199
200 clockevents_register_device(ce_dev);
201 if (request_irq(ce_dev->irq, timer_interrupt, flag, "rtos_timer", NULL))
202 pr_err("Failed to register rtos_timer interrupt\n");
203}
204
205void __init time_init(void)
206{
207 late_time_init = time_init_deferred;
208}
209
210void __delay(unsigned long cycles)
211{
212 unsigned long long start = __vmgettime();
213
214 while ((__vmgettime() - start) < cycles)
215 cpu_relax();
216}
217EXPORT_SYMBOL(__delay);
218
219/*
220 * This could become parametric or perhaps even computed at run-time,
221 * but for now we take the observed simulator jitter.
222 */
223static long long fudgefactor = 350; /* Maybe lower if kernel optimized. */
224
225void __udelay(unsigned long usecs)
226{
227 unsigned long long start = __vmgettime();
228 unsigned long long finish = (pcycle_freq_mhz * usecs) - fudgefactor;
229
230 while ((__vmgettime() - start) < finish)
231 cpu_relax(); /* not sure how this improves readability */
232}
233EXPORT_SYMBOL(__udelay);
234
235bool delay_read_timer(unsigned long *timer_val)
236{
237 *timer_val = __vmgettime();
238 return true;
239}