projects/linux·blob assoc-array-fixes · refs

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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * arch/arm/mach-pxa/time.c
4 *
5 * PXA clocksource, clockevents, and OST interrupt handlers.
6 * Copyright (c) 2007 by Bill Gatliff <[email protected]>.
7 *
8 * Derived from Nicolas Pitre's PXA timer handler Copyright (c) 2001
9 * by MontaVista Software, Inc. (Nico, your code rocks!)
10 */
11
12#include <linux/kernel.h>
13#include <linux/init.h>
14#include <linux/interrupt.h>
15#include <linux/clk.h>
16#include <linux/clockchips.h>
17#include <linux/of_address.h>
18#include <linux/of_irq.h>
19#include <linux/sched/clock.h>
20#include <linux/sched_clock.h>
21
22#include <clocksource/pxa.h>
23
24#include <asm/div64.h>
25
26#define OSMR0 0x00 /* OS Timer 0 Match Register */
27#define OSMR1 0x04 /* OS Timer 1 Match Register */
28#define OSMR2 0x08 /* OS Timer 2 Match Register */
29#define OSMR3 0x0C /* OS Timer 3 Match Register */
30
31#define OSCR 0x10 /* OS Timer Counter Register */
32#define OSSR 0x14 /* OS Timer Status Register */
33#define OWER 0x18 /* OS Timer Watchdog Enable Register */
34#define OIER 0x1C /* OS Timer Interrupt Enable Register */
35
36#define OSSR_M3 (1 << 3) /* Match status channel 3 */
37#define OSSR_M2 (1 << 2) /* Match status channel 2 */
38#define OSSR_M1 (1 << 1) /* Match status channel 1 */
39#define OSSR_M0 (1 << 0) /* Match status channel 0 */
40
41#define OIER_E0 (1 << 0) /* Interrupt enable channel 0 */
42
43/*
44 * This is PXA's sched_clock implementation. This has a resolution
45 * of at least 308 ns and a maximum value of 208 days.
46 *
47 * The return value is guaranteed to be monotonic in that range as
48 * long as there is always less than 582 seconds between successive
49 * calls to sched_clock() which should always be the case in practice.
50 */
51
52#define timer_readl(reg) readl_relaxed(timer_base + (reg))
53#define timer_writel(val, reg) writel_relaxed((val), timer_base + (reg))
54
55static void __iomem *timer_base;
56
57static u64 notrace pxa_read_sched_clock(void)
58{
59 return timer_readl(OSCR);
60}
61
62
63#define MIN_OSCR_DELTA 16
64
65static irqreturn_t
66pxa_ost0_interrupt(int irq, void *dev_id)
67{
68 struct clock_event_device *c = dev_id;
69
70 /* Disarm the compare/match, signal the event. */
71 timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
72 timer_writel(OSSR_M0, OSSR);
73 c->event_handler(c);
74
75 return IRQ_HANDLED;
76}
77
78static int
79pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev)
80{
81 unsigned long next, oscr;
82
83 timer_writel(timer_readl(OIER) | OIER_E0, OIER);
84 next = timer_readl(OSCR) + delta;
85 timer_writel(next, OSMR0);
86 oscr = timer_readl(OSCR);
87
88 return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
89}
90
91static int pxa_osmr0_shutdown(struct clock_event_device *evt)
92{
93 /* initializing, released, or preparing for suspend */
94 timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
95 timer_writel(OSSR_M0, OSSR);
96 return 0;
97}
98
99#ifdef CONFIG_PM
100static unsigned long osmr[4], oier, oscr;
101
102static void pxa_timer_suspend(struct clock_event_device *cedev)
103{
104 osmr[0] = timer_readl(OSMR0);
105 osmr[1] = timer_readl(OSMR1);
106 osmr[2] = timer_readl(OSMR2);
107 osmr[3] = timer_readl(OSMR3);
108 oier = timer_readl(OIER);
109 oscr = timer_readl(OSCR);
110}
111
112static void pxa_timer_resume(struct clock_event_device *cedev)
113{
114 /*
115 * Ensure that we have at least MIN_OSCR_DELTA between match
116 * register 0 and the OSCR, to guarantee that we will receive
117 * the one-shot timer interrupt. We adjust OSMR0 in preference
118 * to OSCR to guarantee that OSCR is monotonically incrementing.
119 */
120 if (osmr[0] - oscr < MIN_OSCR_DELTA)
121 osmr[0] += MIN_OSCR_DELTA;
122
123 timer_writel(osmr[0], OSMR0);
124 timer_writel(osmr[1], OSMR1);
125 timer_writel(osmr[2], OSMR2);
126 timer_writel(osmr[3], OSMR3);
127 timer_writel(oier, OIER);
128 timer_writel(oscr, OSCR);
129}
130#else
131#define pxa_timer_suspend NULL
132#define pxa_timer_resume NULL
133#endif
134
135static struct clock_event_device ckevt_pxa_osmr0 = {
136 .name = "osmr0",
137 .features = CLOCK_EVT_FEAT_ONESHOT,
138 .rating = 200,
139 .set_next_event = pxa_osmr0_set_next_event,
140 .set_state_shutdown = pxa_osmr0_shutdown,
141 .set_state_oneshot = pxa_osmr0_shutdown,
142 .suspend = pxa_timer_suspend,
143 .resume = pxa_timer_resume,
144};
145
146static int __init pxa_timer_common_init(int irq, unsigned long clock_tick_rate)
147{
148 int ret;
149
150 timer_writel(0, OIER);
151 timer_writel(OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3, OSSR);
152
153 sched_clock_register(pxa_read_sched_clock, 32, clock_tick_rate);
154
155 ckevt_pxa_osmr0.cpumask = cpumask_of(0);
156
157 ret = request_irq(irq, pxa_ost0_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
158 "ost0", &ckevt_pxa_osmr0);
159 if (ret) {
160 pr_err("Failed to setup irq\n");
161 return ret;
162 }
163
164 ret = clocksource_mmio_init(timer_base + OSCR, "oscr0", clock_tick_rate, 200,
165 32, clocksource_mmio_readl_up);
166 if (ret) {
167 pr_err("Failed to init clocksource\n");
168 return ret;
169 }
170
171 clockevents_config_and_register(&ckevt_pxa_osmr0, clock_tick_rate,
172 MIN_OSCR_DELTA * 2, 0x7fffffff);
173
174 return 0;
175}
176
177static int __init pxa_timer_dt_init(struct device_node *np)
178{
179 struct clk *clk;
180 int irq, ret;
181
182 /* timer registers are shared with watchdog timer */
183 timer_base = of_iomap(np, 0);
184 if (!timer_base) {
185 pr_err("%pOFn: unable to map resource\n", np);
186 return -ENXIO;
187 }
188
189 clk = of_clk_get(np, 0);
190 if (IS_ERR(clk)) {
191 pr_crit("%pOFn: unable to get clk\n", np);
192 return PTR_ERR(clk);
193 }
194
195 ret = clk_prepare_enable(clk);
196 if (ret) {
197 pr_crit("Failed to prepare clock\n");
198 return ret;
199 }
200
201 /* we are only interested in OS-timer0 irq */
202 irq = irq_of_parse_and_map(np, 0);
203 if (irq <= 0) {
204 pr_crit("%pOFn: unable to parse OS-timer0 irq\n", np);
205 return -EINVAL;
206 }
207
208 return pxa_timer_common_init(irq, clk_get_rate(clk));
209}
210TIMER_OF_DECLARE(pxa_timer, "marvell,pxa-timer", pxa_timer_dt_init);
211
212/*
213 * Legacy timer init for non device-tree boards.
214 */
215void __init pxa_timer_nodt_init(int irq, void __iomem *base)
216{
217 struct clk *clk;
218
219 timer_base = base;
220 clk = clk_get(NULL, "OSTIMER0");
221 if (clk && !IS_ERR(clk)) {
222 clk_prepare_enable(clk);
223 pxa_timer_common_init(irq, clk_get_rate(clk));
224 } else {
225 pr_crit("%s: unable to get clk\n", __func__);
226 }
227}