1// SPDX-License-Identifier: GPL-2.0
2// Copyright (C) 2005-2017 Andes Technology Corporation
3/*
4 *  Andestech ATCPIT100 Timer Device Driver Implementation
5 * Rick Chen, Andes Technology Corporation <rick@andestech.com>
6 *
7 */
8
9#include <linux/irq.h>
10#include <linux/clocksource.h>
11#include <linux/clockchips.h>
12#include <linux/interrupt.h>
13#include <linux/ioport.h>
14#include <linux/cpufreq.h>
15#include <linux/sched.h>
16#include <linux/sched_clock.h>
17#include <linux/of_address.h>
18#include <linux/of_irq.h>
19#include <linux/of_platform.h>
20#include "timer-of.h"
21#ifdef CONFIG_NDS32
22#include <asm/vdso_timer_info.h>
23#endif
24
25/*
26 * Definition of register offsets
27 */
28
29/* ID and Revision Register */
30#define ID_REV		0x0
31
32/* Configuration Register */
33#define CFG		0x10
34
35/* Interrupt Enable Register */
36#define INT_EN		0x14
37#define CH_INT_EN(c, i)	((1<<i)<<(4*c))
38#define CH0INT0EN	0x01
39
40/* Interrupt Status Register */
41#define INT_STA		0x18
42#define CH0INT0		0x01
43
44/* Channel Enable Register */
45#define CH_EN		0x1C
46#define CH0TMR0EN	0x1
47#define CH1TMR0EN	0x10
48
49/* Channel 0 , 1 Control Register */
50#define CH0_CTL		(0x20)
51#define CH1_CTL		(0x20 + 0x10)
52
53/* Channel clock source , bit 3 , 0:External clock , 1:APB clock */
54#define APB_CLK		BIT(3)
55
56/* Channel mode , bit 0~2 */
57#define TMR_32		0x1
58#define TMR_16		0x2
59#define TMR_8		0x3
60
61/* Channel 0 , 1 Reload Register */
62#define CH0_REL		(0x24)
63#define CH1_REL		(0x24 + 0x10)
64
65/* Channel 0 , 1 Counter Register */
66#define CH0_CNT		(0x28)
67#define CH1_CNT		(0x28 + 0x10)
68
69#define TIMER_SYNC_TICKS	3
70
71static void atcpit100_ch1_tmr0_en(void __iomem *base)
72{
73	writel(~0, base + CH1_REL);
74	writel(APB_CLK|TMR_32, base + CH1_CTL);
75}
76
77static void atcpit100_ch0_tmr0_en(void __iomem *base)
78{
79	writel(APB_CLK|TMR_32, base + CH0_CTL);
80}
81
82static void atcpit100_clkevt_time_setup(void __iomem *base, unsigned long delay)
83{
84	writel(delay, base + CH0_CNT);
85	writel(delay, base + CH0_REL);
86}
87
88static void atcpit100_timer_clear_interrupt(void __iomem *base)
89{
90	u32 val;
91
92	val = readl(base + INT_STA);
93	writel(val | CH0INT0, base + INT_STA);
94}
95
96static void atcpit100_clocksource_start(void __iomem *base)
97{
98	u32 val;
99
100	val = readl(base + CH_EN);
101	writel(val | CH1TMR0EN, base + CH_EN);
102}
103
104static void atcpit100_clkevt_time_start(void __iomem *base)
105{
106	u32 val;
107
108	val = readl(base + CH_EN);
109	writel(val | CH0TMR0EN, base + CH_EN);
110}
111
112static void atcpit100_clkevt_time_stop(void __iomem *base)
113{
114	u32 val;
115
116	atcpit100_timer_clear_interrupt(base);
117	val = readl(base + CH_EN);
118	writel(val & ~CH0TMR0EN, base + CH_EN);
119}
120
121static int atcpit100_clkevt_next_event(unsigned long evt,
122	struct clock_event_device *clkevt)
123{
124	u32 val;
125	struct timer_of *to = to_timer_of(clkevt);
126
127	val = readl(timer_of_base(to) + CH_EN);
128	writel(val & ~CH0TMR0EN, timer_of_base(to) + CH_EN);
129	writel(evt, timer_of_base(to) + CH0_REL);
130	writel(val | CH0TMR0EN, timer_of_base(to) + CH_EN);
131
132	return 0;
133}
134
135static int atcpit100_clkevt_set_periodic(struct clock_event_device *evt)
136{
137	struct timer_of *to = to_timer_of(evt);
138
139	atcpit100_clkevt_time_setup(timer_of_base(to), timer_of_period(to));
140	atcpit100_clkevt_time_start(timer_of_base(to));
141
142	return 0;
143}
144static int atcpit100_clkevt_shutdown(struct clock_event_device *evt)
145{
146	struct timer_of *to = to_timer_of(evt);
147
148	atcpit100_clkevt_time_stop(timer_of_base(to));
149
150	return 0;
151}
152static int atcpit100_clkevt_set_oneshot(struct clock_event_device *evt)
153{
154	struct timer_of *to = to_timer_of(evt);
155	u32 val;
156
157	writel(~0x0, timer_of_base(to) + CH0_REL);
158	val = readl(timer_of_base(to) + CH_EN);
159	writel(val | CH0TMR0EN, timer_of_base(to) + CH_EN);
160
161	return 0;
162}
163
164static irqreturn_t atcpit100_timer_interrupt(int irq, void *dev_id)
165{
166	struct clock_event_device *evt = (struct clock_event_device *)dev_id;
167	struct timer_of *to = to_timer_of(evt);
168
169	atcpit100_timer_clear_interrupt(timer_of_base(to));
170
171	evt->event_handler(evt);
172
173	return IRQ_HANDLED;
174}
175
176static struct timer_of to = {
177	.flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE,
178
179	.clkevt = {
180		.name = "atcpit100_tick",
181		.rating = 300,
182		.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
183		.set_state_shutdown = atcpit100_clkevt_shutdown,
184		.set_state_periodic = atcpit100_clkevt_set_periodic,
185		.set_state_oneshot = atcpit100_clkevt_set_oneshot,
186		.tick_resume = atcpit100_clkevt_shutdown,
187		.set_next_event = atcpit100_clkevt_next_event,
188		.cpumask = cpu_possible_mask,
189	},
190
191	.of_irq = {
192		.handler = atcpit100_timer_interrupt,
193		.flags = IRQF_TIMER | IRQF_IRQPOLL,
194	},
195
196	/*
197	 * FIXME: we currently only support clocking using PCLK
198	 * and using EXTCLK is not supported in the driver.
199	 */
200	.of_clk = {
201		.name = "PCLK",
202	}
203};
204
205static u64 notrace atcpit100_timer_sched_read(void)
206{
207	return ~readl(timer_of_base(&to) + CH1_CNT);
208}
209
210#ifdef CONFIG_NDS32
211static void fill_vdso_need_info(struct device_node *node)
212{
213	struct resource timer_res;
214	of_address_to_resource(node, 0, &timer_res);
215	timer_info.mapping_base = (unsigned long)timer_res.start;
216	timer_info.cycle_count_down = true;
217	timer_info.cycle_count_reg_offset = CH1_CNT;
218}
219#endif
220
221static int __init atcpit100_timer_init(struct device_node *node)
222{
223	int ret;
224	u32 val;
225	void __iomem *base;
226
227	ret = timer_of_init(node, &to);
228	if (ret)
229		return ret;
230
231	base = timer_of_base(&to);
232
233	sched_clock_register(atcpit100_timer_sched_read, 32,
234		timer_of_rate(&to));
235
236	ret = clocksource_mmio_init(base + CH1_CNT,
237		node->name, timer_of_rate(&to), 300, 32,
238		clocksource_mmio_readl_down);
239
240	if (ret) {
241		pr_err("Failed to register clocksource\n");
242		return ret;
243	}
244
245	/* clear channel 0 timer0 interrupt */
246	atcpit100_timer_clear_interrupt(base);
247
248	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
249					TIMER_SYNC_TICKS, 0xffffffff);
250	atcpit100_ch0_tmr0_en(base);
251	atcpit100_ch1_tmr0_en(base);
252	atcpit100_clocksource_start(base);
253	atcpit100_clkevt_time_start(base);
254
255	/* Enable channel 0 timer0 interrupt */
256	val = readl(base + INT_EN);
257	writel(val | CH0INT0EN, base + INT_EN);
258
259#ifdef CONFIG_NDS32
260	fill_vdso_need_info(node);
261#endif
262
263	return ret;
264}
265
266TIMER_OF_DECLARE(atcpit100, "andestech,atcpit100", atcpit100_timer_init);
267