1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2012 Altera Corporation
4 * Copyright (c) 2011 Picochip Ltd., Jamie Iles
5 *
6 * Modified from mach-picoxcell/time.c
7 */
8 #include <linux/delay.h>
9 #include <linux/dw_apb_timer.h>
10 #include <linux/of.h>
11 #include <linux/of_address.h>
12 #include <linux/of_irq.h>
13 #include <linux/clk.h>
14 #include <linux/reset.h>
15 #include <linux/sched_clock.h>
16
timer_get_base_and_rate(struct device_node * np,void __iomem ** base,u32 * rate)17 static int __init timer_get_base_and_rate(struct device_node *np,
18 void __iomem **base, u32 *rate)
19 {
20 struct clk *timer_clk;
21 struct clk *pclk;
22 struct reset_control *rstc;
23 int ret;
24
25 *base = of_iomap(np, 0);
26
27 if (!*base)
28 panic("Unable to map regs for %pOFn", np);
29
30 /*
31 * Reset the timer if the reset control is available, wiping
32 * out the state the firmware may have left it
33 */
34 rstc = of_reset_control_get(np, NULL);
35 if (!IS_ERR(rstc)) {
36 reset_control_assert(rstc);
37 reset_control_deassert(rstc);
38 }
39
40 /*
41 * Not all implementations use a peripheral clock, so don't panic
42 * if it's not present
43 */
44 pclk = of_clk_get_by_name(np, "pclk");
45 if (!IS_ERR(pclk))
46 if (clk_prepare_enable(pclk))
47 pr_warn("pclk for %pOFn is present, but could not be activated\n",
48 np);
49
50 if (!of_property_read_u32(np, "clock-freq", rate) &&
51 !of_property_read_u32(np, "clock-frequency", rate))
52 return 0;
53
54 timer_clk = of_clk_get_by_name(np, "timer");
55 if (IS_ERR(timer_clk)) {
56 ret = PTR_ERR(timer_clk);
57 goto out_pclk_disable;
58 }
59
60 ret = clk_prepare_enable(timer_clk);
61 if (ret)
62 goto out_timer_clk_put;
63
64 *rate = clk_get_rate(timer_clk);
65 if (!(*rate)) {
66 ret = -EINVAL;
67 goto out_timer_clk_disable;
68 }
69
70 return 0;
71
72 out_timer_clk_disable:
73 clk_disable_unprepare(timer_clk);
74 out_timer_clk_put:
75 clk_put(timer_clk);
76 out_pclk_disable:
77 if (!IS_ERR(pclk)) {
78 clk_disable_unprepare(pclk);
79 clk_put(pclk);
80 }
81 iounmap(*base);
82 return ret;
83 }
84
add_clockevent(struct device_node * event_timer)85 static int __init add_clockevent(struct device_node *event_timer)
86 {
87 void __iomem *iobase;
88 struct dw_apb_clock_event_device *ced;
89 u32 irq, rate;
90 int ret = 0;
91
92 irq = irq_of_parse_and_map(event_timer, 0);
93 if (irq == 0)
94 panic("No IRQ for clock event timer");
95
96 ret = timer_get_base_and_rate(event_timer, &iobase, &rate);
97 if (ret)
98 return ret;
99
100 ced = dw_apb_clockevent_init(-1, event_timer->name, 300, iobase, irq,
101 rate);
102 if (!ced)
103 return -EINVAL;
104
105 dw_apb_clockevent_register(ced);
106
107 return 0;
108 }
109
110 static void __iomem *sched_io_base;
111 static u32 sched_rate;
112
add_clocksource(struct device_node * source_timer)113 static int __init add_clocksource(struct device_node *source_timer)
114 {
115 void __iomem *iobase;
116 struct dw_apb_clocksource *cs;
117 u32 rate;
118 int ret;
119
120 ret = timer_get_base_and_rate(source_timer, &iobase, &rate);
121 if (ret)
122 return ret;
123
124 cs = dw_apb_clocksource_init(300, source_timer->name, iobase, rate);
125 if (!cs)
126 return -EINVAL;
127
128 dw_apb_clocksource_start(cs);
129 dw_apb_clocksource_register(cs);
130
131 /*
132 * Fallback to use the clocksource as sched_clock if no separate
133 * timer is found. sched_io_base then points to the current_value
134 * register of the clocksource timer.
135 */
136 sched_io_base = iobase + 0x04;
137 sched_rate = rate;
138
139 return 0;
140 }
141
read_sched_clock(void)142 static u64 notrace read_sched_clock(void)
143 {
144 return ~readl_relaxed(sched_io_base);
145 }
146
147 static const struct of_device_id sptimer_ids[] __initconst = {
148 { .compatible = "picochip,pc3x2-rtc" },
149 { /* Sentinel */ },
150 };
151
init_sched_clock(void)152 static void __init init_sched_clock(void)
153 {
154 struct device_node *sched_timer;
155
156 sched_timer = of_find_matching_node(NULL, sptimer_ids);
157 if (sched_timer) {
158 timer_get_base_and_rate(sched_timer, &sched_io_base,
159 &sched_rate);
160 of_node_put(sched_timer);
161 }
162
163 sched_clock_register(read_sched_clock, 32, sched_rate);
164 }
165
166 #ifdef CONFIG_ARM
dw_apb_delay_timer_read(void)167 static unsigned long dw_apb_delay_timer_read(void)
168 {
169 return ~readl_relaxed(sched_io_base);
170 }
171
172 static struct delay_timer dw_apb_delay_timer = {
173 .read_current_timer = dw_apb_delay_timer_read,
174 };
175 #endif
176
177 static int num_called;
dw_apb_timer_init(struct device_node * timer)178 static int __init dw_apb_timer_init(struct device_node *timer)
179 {
180 int ret = 0;
181
182 switch (num_called) {
183 case 1:
184 pr_debug("%s: found clocksource timer\n", __func__);
185 ret = add_clocksource(timer);
186 if (ret)
187 return ret;
188 init_sched_clock();
189 #ifdef CONFIG_ARM
190 dw_apb_delay_timer.freq = sched_rate;
191 register_current_timer_delay(&dw_apb_delay_timer);
192 #endif
193 break;
194 default:
195 pr_debug("%s: found clockevent timer\n", __func__);
196 ret = add_clockevent(timer);
197 if (ret)
198 return ret;
199 break;
200 }
201
202 num_called++;
203
204 return 0;
205 }
206 TIMER_OF_DECLARE(pc3x2_timer, "picochip,pc3x2-timer", dw_apb_timer_init);
207 TIMER_OF_DECLARE(apb_timer_osc, "snps,dw-apb-timer-osc", dw_apb_timer_init);
208 TIMER_OF_DECLARE(apb_timer_sp, "snps,dw-apb-timer-sp", dw_apb_timer_init);
209 TIMER_OF_DECLARE(apb_timer, "snps,dw-apb-timer", dw_apb_timer_init);
210
