1// SPDX-License-Identifier: GPL-2.0+
2//
3// Copyright 2017-2019 NXP
4
5#include <linux/interrupt.h>
6#include <linux/clockchips.h>
7#include <linux/slab.h>
8
9#include "timer-of.h"
10
11#define CMP_OFFSET 0x10000
12#define RD_OFFSET 0x20000
13
14#define CNTCV_LO 0x8
15#define CNTCV_HI 0xc
16#define CMPCV_LO (CMP_OFFSET + 0x20)
17#define CMPCV_HI (CMP_OFFSET + 0x24)
18#define CMPCR (CMP_OFFSET + 0x2c)
19#define CNTCV_LO_IMX95 (RD_OFFSET + 0x8)
20#define CNTCV_HI_IMX95 (RD_OFFSET + 0xc)
21
22#define SYS_CTR_EN 0x1
23#define SYS_CTR_IRQ_MASK 0x2
24
25#define SYS_CTR_CLK_DIV 0x3
26
27struct sysctr_private {
28 u32 cmpcr;
29 u32 lo_off;
30 u32 hi_off;
31};
32
33static void sysctr_timer_enable(struct clock_event_device *evt, bool enable)
34{
35 struct timer_of *to = to_timer_of(clkevt: evt);
36 struct sysctr_private *priv = to->private_data;
37 void __iomem *base = timer_of_base(to);
38
39 writel(val: enable ? priv->cmpcr | SYS_CTR_EN : priv->cmpcr, addr: base + CMPCR);
40}
41
42static void sysctr_irq_acknowledge(struct clock_event_device *evt)
43{
44 /*
45 * clear the enable bit(EN =0) will clear
46 * the status bit(ISTAT = 0), then the interrupt
47 * signal will be negated(acknowledged).
48 */
49 sysctr_timer_enable(evt, enable: false);
50}
51
52static inline u64 sysctr_read_counter(struct clock_event_device *evt)
53{
54 struct timer_of *to = to_timer_of(clkevt: evt);
55 struct sysctr_private *priv = to->private_data;
56 void __iomem *base = timer_of_base(to);
57 u32 cnt_hi, tmp_hi, cnt_lo;
58
59 do {
60 cnt_hi = readl_relaxed(base + priv->hi_off);
61 cnt_lo = readl_relaxed(base + priv->lo_off);
62 tmp_hi = readl_relaxed(base + priv->hi_off);
63 } while (tmp_hi != cnt_hi);
64
65 return ((u64) cnt_hi << 32) | cnt_lo;
66}
67
68static int sysctr_set_next_event(unsigned long delta,
69 struct clock_event_device *evt)
70{
71 struct timer_of *to = to_timer_of(clkevt: evt);
72 void __iomem *base = timer_of_base(to);
73 u32 cmp_hi, cmp_lo;
74 u64 next;
75
76 sysctr_timer_enable(evt, enable: false);
77
78 next = sysctr_read_counter(evt);
79
80 next += delta;
81
82 cmp_hi = (next >> 32) & 0x00fffff;
83 cmp_lo = next & 0xffffffff;
84
85 writel_relaxed(cmp_hi, base + CMPCV_HI);
86 writel_relaxed(cmp_lo, base + CMPCV_LO);
87
88 sysctr_timer_enable(evt, enable: true);
89
90 return 0;
91}
92
93static int sysctr_set_state_oneshot(struct clock_event_device *evt)
94{
95 return 0;
96}
97
98static int sysctr_set_state_shutdown(struct clock_event_device *evt)
99{
100 sysctr_timer_enable(evt, enable: false);
101
102 return 0;
103}
104
105static irqreturn_t sysctr_timer_interrupt(int irq, void *dev_id)
106{
107 struct clock_event_device *evt = dev_id;
108
109 sysctr_irq_acknowledge(evt);
110
111 evt->event_handler(evt);
112
113 return IRQ_HANDLED;
114}
115
116static struct timer_of to_sysctr = {
117 .flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE,
118 .clkevt = {
119 .name = "i.MX system counter timer",
120 .features = CLOCK_EVT_FEAT_ONESHOT |
121 CLOCK_EVT_FEAT_DYNIRQ,
122 .set_state_oneshot = sysctr_set_state_oneshot,
123 .set_next_event = sysctr_set_next_event,
124 .set_state_shutdown = sysctr_set_state_shutdown,
125 .rating = 200,
126 },
127 .of_irq = {
128 .handler = sysctr_timer_interrupt,
129 .flags = IRQF_TIMER,
130 },
131 .of_clk = {
132 .name = "per",
133 },
134};
135
136static int __init __sysctr_timer_init(struct device_node *np)
137{
138 struct sysctr_private *priv;
139 void __iomem *base;
140 int ret;
141
142 priv = kzalloc(sizeof(struct sysctr_private), GFP_KERNEL);
143 if (!priv)
144 return -ENOMEM;
145
146 ret = timer_of_init(np, to: &to_sysctr);
147 if (ret) {
148 kfree(objp: priv);
149 return ret;
150 }
151
152 if (!of_property_read_bool(np, propname: "nxp,no-divider")) {
153 /* system counter clock is divided by 3 internally */
154 to_sysctr.of_clk.rate /= SYS_CTR_CLK_DIV;
155 }
156
157 to_sysctr.clkevt.cpumask = cpu_possible_mask;
158 to_sysctr.private_data = priv;
159
160 base = timer_of_base(to: &to_sysctr);
161 priv->cmpcr = readl(addr: base + CMPCR) & ~SYS_CTR_EN;
162
163 return 0;
164}
165
166static int __init sysctr_timer_init(struct device_node *np)
167{
168 struct sysctr_private *priv;
169 int ret;
170
171 ret = __sysctr_timer_init(np);
172 if (ret)
173 return ret;
174
175 priv = to_sysctr.private_data;
176 priv->lo_off = CNTCV_LO;
177 priv->hi_off = CNTCV_HI;
178
179 clockevents_config_and_register(dev: &to_sysctr.clkevt,
180 freq: timer_of_rate(to: &to_sysctr),
181 min_delta: 0xff, max_delta: 0x7fffffff);
182
183 return 0;
184}
185
186static int __init sysctr_timer_imx95_init(struct device_node *np)
187{
188 struct sysctr_private *priv;
189 int ret;
190
191 ret = __sysctr_timer_init(np);
192 if (ret)
193 return ret;
194
195 priv = to_sysctr.private_data;
196 priv->lo_off = CNTCV_LO_IMX95;
197 priv->hi_off = CNTCV_HI_IMX95;
198
199 clockevents_config_and_register(dev: &to_sysctr.clkevt,
200 freq: timer_of_rate(to: &to_sysctr),
201 min_delta: 0xff, max_delta: 0x7fffffff);
202
203 return 0;
204}
205
206TIMER_OF_DECLARE(sysctr_timer, "nxp,sysctr-timer", sysctr_timer_init);
207TIMER_OF_DECLARE(sysctr_timer_imx95, "nxp,imx95-sysctr-timer", sysctr_timer_imx95_init);
208

source code of linux/drivers/clocksource/timer-imx-sysctr.c