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192.168.1.100 / T800 / 0b39b87cb0cd96fd68f16a6d004c85c06a954fb2 / . / src / kernel / linux / v4.19 / arch / mips / ralink / cevt-rt3352.c
blob: 92f284d2b80290cecffe2c0923fdd12c26430992 [file] [log] [blame]
xjb04a4022021-11-25 15:01:52 +0800[diff] [blame]1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2013 by John Crispin <john@phrozen.org>
7 */
8
9#include <linux/clockchips.h>
10#include <linux/clocksource.h>
11#include <linux/interrupt.h>
12#include <linux/reset.h>
13#include <linux/init.h>
14#include <linux/time.h>
15#include <linux/of.h>
16#include <linux/of_irq.h>
17#include <linux/of_address.h>
18
19#include <asm/mach-ralink/ralink_regs.h>
20
21#define SYSTICK_FREQ (50 * 1000)
22
23#define SYSTICK_CONFIG 0x00
24#define SYSTICK_COMPARE 0x04
25#define SYSTICK_COUNT 0x08
26
27/* route systick irq to mips irq 7 instead of the r4k-timer */
28#define CFG_EXT_STK_EN 0x2
29/* enable the counter */
30#define CFG_CNT_EN 0x1
31
32struct systick_device {
33 void __iomem *membase;
34 struct clock_event_device dev;
35 int irq_requested;
36 int freq_scale;
37};
38
39static int systick_set_oneshot(struct clock_event_device *evt);
40static int systick_shutdown(struct clock_event_device *evt);
41
42static int systick_next_event(unsigned long delta,
43 struct clock_event_device *evt)
44{
45 struct systick_device *sdev;
46 u32 count;
47
48 sdev = container_of(evt, struct systick_device, dev);
49 count = ioread32(sdev->membase + SYSTICK_COUNT);
50 count = (count + delta) % SYSTICK_FREQ;
51 iowrite32(count, sdev->membase + SYSTICK_COMPARE);
52
53 return 0;
54}
55
56static void systick_event_handler(struct clock_event_device *dev)
57{
58 /* noting to do here */
59}
60
61static irqreturn_t systick_interrupt(int irq, void *dev_id)
62{
63 struct clock_event_device *dev = (struct clock_event_device *) dev_id;
64
65 dev->event_handler(dev);
66
67 return IRQ_HANDLED;
68}
69
70static struct systick_device systick = {
71 .dev = {
72 /*
73 * cevt-r4k uses 300, make sure systick
74 * gets used if available
75 */
76 .rating = 310,
77 .features = CLOCK_EVT_FEAT_ONESHOT,
78 .set_next_event = systick_next_event,
79 .set_state_shutdown = systick_shutdown,
80 .set_state_oneshot = systick_set_oneshot,
81 .event_handler = systick_event_handler,
82 },
83};
84
85static struct irqaction systick_irqaction = {
86 .handler = systick_interrupt,
87 .flags = IRQF_PERCPU | IRQF_TIMER,
88 .dev_id = &systick.dev,
89};
90
91static int systick_shutdown(struct clock_event_device *evt)
92{
93 struct systick_device *sdev;
94
95 sdev = container_of(evt, struct systick_device, dev);
96
97 if (sdev->irq_requested)
98 free_irq(systick.dev.irq, &systick_irqaction);
99 sdev->irq_requested = 0;
100 iowrite32(0, systick.membase + SYSTICK_CONFIG);
101
102 return 0;
103}
104
105static int systick_set_oneshot(struct clock_event_device *evt)
106{
107 struct systick_device *sdev;
108
109 sdev = container_of(evt, struct systick_device, dev);
110
111 if (!sdev->irq_requested)
112 setup_irq(systick.dev.irq, &systick_irqaction);
113 sdev->irq_requested = 1;
114 iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN,
115 systick.membase + SYSTICK_CONFIG);
116
117 return 0;
118}
119
120static int __init ralink_systick_init(struct device_node *np)
121{
122 int ret;
123
124 systick.membase = of_iomap(np, 0);
125 if (!systick.membase)
126 return -ENXIO;
127
128 systick_irqaction.name = np->name;
129 systick.dev.name = np->name;
130 clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);
131 systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev);
132 systick.dev.max_delta_ticks = 0x7fff;
133 systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);
134 systick.dev.min_delta_ticks = 0x3;
135 systick.dev.irq = irq_of_parse_and_map(np, 0);
136 if (!systick.dev.irq) {
137 pr_err("%s: request_irq failed", np->name);
138 return -EINVAL;
139 }
140
141 ret = clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
142 SYSTICK_FREQ, 301, 16,
143 clocksource_mmio_readl_up);
144 if (ret)
145 return ret;
146
147 clockevents_register_device(&systick.dev);
148
149 pr_info("%s: running - mult: %d, shift: %d\n",
150 np->name, systick.dev.mult, systick.dev.shift);
151
152 return 0;
153}
154
155TIMER_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);