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1 | /* |
2 | * Marvell Armada 370/XP SoC timer handling. |
3 | * |
4 | * Copyright (C) 2012 Marvell |
5 | * |
6 | * Lior Amsalem <alior@marvell.com> |
7 | * Gregory CLEMENT <gregory.clement@free-electrons.com> |
8 | * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
9 | * |
10 | * This file is licensed under the terms of the GNU General Public |
11 | * License version 2. This program is licensed "as is" without any |
12 | * warranty of any kind, whether express or implied. |
13 | * |
14 | * Timer 0 is used as free-running clocksource, while timer 1 is |
15 | * used as clock_event_device. |
16 | */ |
17 | |
18 | #include <linux/init.h> |
19 | #include <linux/platform_device.h> |
20 | #include <linux/kernel.h> |
21 | #include <linux/clk.h> |
22 | #include <linux/timer.h> |
23 | #include <linux/clockchips.h> |
24 | #include <linux/interrupt.h> |
25 | #include <linux/of.h> |
26 | #include <linux/of_irq.h> |
27 | #include <linux/of_address.h> |
28 | #include <linux/irq.h> |
29 | #include <linux/module.h> |
30 | |
31 | #include <asm/sched_clock.h> |
32 | #include <asm/localtimer.h> |
33 | #include <linux/percpu.h> |
34 | /* |
35 | * Timer block registers. |
36 | */ |
37 | #define TIMER_CTRL_OFF 0x0000 |
38 | #define TIMER0_EN 0x0001 |
39 | #define TIMER0_RELOAD_EN 0x0002 |
40 | #define TIMER0_25MHZ 0x0800 |
41 | #define TIMER0_DIV(div) ((div) << 19) |
42 | #define TIMER1_EN 0x0004 |
43 | #define TIMER1_RELOAD_EN 0x0008 |
44 | #define TIMER1_25MHZ 0x1000 |
45 | #define TIMER1_DIV(div) ((div) << 22) |
46 | #define TIMER_EVENTS_STATUS 0x0004 |
47 | #define TIMER0_CLR_MASK (~0x1) |
48 | #define TIMER1_CLR_MASK (~0x100) |
49 | #define TIMER0_RELOAD_OFF 0x0010 |
50 | #define TIMER0_VAL_OFF 0x0014 |
51 | #define TIMER1_RELOAD_OFF 0x0018 |
52 | #define TIMER1_VAL_OFF 0x001c |
53 | |
54 | #define LCL_TIMER_EVENTS_STATUS 0x0028 |
55 | /* Global timers are connected to the coherency fabric clock, and the |
56 | below divider reduces their incrementing frequency. */ |
57 | #define TIMER_DIVIDER_SHIFT 5 |
58 | #define TIMER_DIVIDER (1 << TIMER_DIVIDER_SHIFT) |
59 | |
60 | /* |
61 | * SoC-specific data. |
62 | */ |
63 | static void __iomem *timer_base, *local_base; |
64 | static unsigned int timer_clk; |
65 | static bool timer25Mhz = true; |
66 | |
67 | /* |
68 | * Number of timer ticks per jiffy. |
69 | */ |
70 | static u32 ticks_per_jiffy; |
71 | |
72 | static struct clock_event_device __percpu **percpu_armada_370_xp_evt; |
73 | |
74 | static u32 notrace armada_370_xp_read_sched_clock(void) |
75 | { |
76 | return ~readl(timer_base + TIMER0_VAL_OFF); |
77 | } |
78 | |
79 | /* |
80 | * Clockevent handling. |
81 | */ |
82 | static int |
83 | armada_370_xp_clkevt_next_event(unsigned long delta, |
84 | struct clock_event_device *dev) |
85 | { |
86 | u32 u; |
87 | /* |
88 | * Clear clockevent timer interrupt. |
89 | */ |
90 | writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS); |
91 | |
92 | /* |
93 | * Setup new clockevent timer value. |
94 | */ |
95 | writel(delta, local_base + TIMER0_VAL_OFF); |
96 | |
97 | /* |
98 | * Enable the timer. |
99 | */ |
100 | u = readl(local_base + TIMER_CTRL_OFF); |
101 | u = ((u & ~TIMER0_RELOAD_EN) | TIMER0_EN | |
102 | TIMER0_DIV(TIMER_DIVIDER_SHIFT)); |
103 | writel(u, local_base + TIMER_CTRL_OFF); |
104 | |
105 | return 0; |
106 | } |
107 | |
108 | static void |
109 | armada_370_xp_clkevt_mode(enum clock_event_mode mode, |
110 | struct clock_event_device *dev) |
111 | { |
112 | u32 u; |
113 | |
114 | if (mode == CLOCK_EVT_MODE_PERIODIC) { |
115 | |
116 | /* |
117 | * Setup timer to fire at 1/HZ intervals. |
118 | */ |
119 | writel(ticks_per_jiffy - 1, local_base + TIMER0_RELOAD_OFF); |
120 | writel(ticks_per_jiffy - 1, local_base + TIMER0_VAL_OFF); |
121 | |
122 | /* |
123 | * Enable timer. |
124 | */ |
125 | |
126 | u = readl(local_base + TIMER_CTRL_OFF); |
127 | |
128 | writel((u | TIMER0_EN | TIMER0_RELOAD_EN | |
129 | TIMER0_DIV(TIMER_DIVIDER_SHIFT)), |
130 | local_base + TIMER_CTRL_OFF); |
131 | } else { |
132 | /* |
133 | * Disable timer. |
134 | */ |
135 | u = readl(local_base + TIMER_CTRL_OFF); |
136 | writel(u & ~TIMER0_EN, local_base + TIMER_CTRL_OFF); |
137 | |
138 | /* |
139 | * ACK pending timer interrupt. |
140 | */ |
141 | writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS); |
142 | } |
143 | } |
144 | |
145 | static struct clock_event_device armada_370_xp_clkevt = { |
146 | .name = "armada_370_xp_per_cpu_tick", |
147 | .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC, |
148 | .shift = 32, |
149 | .rating = 300, |
150 | .set_next_event = armada_370_xp_clkevt_next_event, |
151 | .set_mode = armada_370_xp_clkevt_mode, |
152 | }; |
153 | |
154 | static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id) |
155 | { |
156 | /* |
157 | * ACK timer interrupt and call event handler. |
158 | */ |
159 | struct clock_event_device *evt = *(struct clock_event_device **)dev_id; |
160 | |
161 | writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS); |
162 | evt->event_handler(evt); |
163 | |
164 | return IRQ_HANDLED; |
165 | } |
166 | |
167 | /* |
168 | * Setup the local clock events for a CPU. |
169 | */ |
170 | static int __cpuinit armada_370_xp_timer_setup(struct clock_event_device *evt) |
171 | { |
172 | u32 u; |
173 | int cpu = smp_processor_id(); |
174 | |
175 | /* Use existing clock_event for cpu 0 */ |
176 | if (!smp_processor_id()) |
177 | return 0; |
178 | |
179 | u = readl(local_base + TIMER_CTRL_OFF); |
180 | if (timer25Mhz) |
181 | writel(u | TIMER0_25MHZ, local_base + TIMER_CTRL_OFF); |
182 | else |
183 | writel(u & ~TIMER0_25MHZ, local_base + TIMER_CTRL_OFF); |
184 | |
185 | evt->name = armada_370_xp_clkevt.name; |
186 | evt->irq = armada_370_xp_clkevt.irq; |
187 | evt->features = armada_370_xp_clkevt.features; |
188 | evt->shift = armada_370_xp_clkevt.shift; |
189 | evt->rating = armada_370_xp_clkevt.rating, |
190 | evt->set_next_event = armada_370_xp_clkevt_next_event, |
191 | evt->set_mode = armada_370_xp_clkevt_mode, |
192 | evt->cpumask = cpumask_of(cpu); |
193 | |
194 | *__this_cpu_ptr(percpu_armada_370_xp_evt) = evt; |
195 | |
196 | clockevents_config_and_register(evt, timer_clk, 1, 0xfffffffe); |
197 | enable_percpu_irq(evt->irq, 0); |
198 | |
199 | return 0; |
200 | } |
201 | |
202 | static void armada_370_xp_timer_stop(struct clock_event_device *evt) |
203 | { |
204 | evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); |
205 | disable_percpu_irq(evt->irq); |
206 | } |
207 | |
208 | static struct local_timer_ops armada_370_xp_local_timer_ops __cpuinitdata = { |
209 | .setup = armada_370_xp_timer_setup, |
210 | .stop = armada_370_xp_timer_stop, |
211 | }; |
212 | |
213 | void __init armada_370_xp_timer_init(void) |
214 | { |
215 | u32 u; |
216 | struct device_node *np; |
217 | int res; |
218 | |
219 | np = of_find_compatible_node(NULL, NULL, "marvell,armada-370-xp-timer"); |
220 | timer_base = of_iomap(np, 0); |
221 | WARN_ON(!timer_base); |
222 | local_base = of_iomap(np, 1); |
223 | |
224 | if (of_find_property(np, "marvell,timer-25Mhz", NULL)) { |
225 | /* The fixed 25MHz timer is available so let's use it */ |
226 | u = readl(local_base + TIMER_CTRL_OFF); |
227 | writel(u | TIMER0_25MHZ, |
228 | local_base + TIMER_CTRL_OFF); |
229 | u = readl(timer_base + TIMER_CTRL_OFF); |
230 | writel(u | TIMER0_25MHZ, |
231 | timer_base + TIMER_CTRL_OFF); |
232 | timer_clk = 25000000; |
233 | } else { |
234 | unsigned long rate = 0; |
235 | struct clk *clk = of_clk_get(np, 0); |
236 | WARN_ON(IS_ERR(clk)); |
237 | rate = clk_get_rate(clk); |
238 | u = readl(local_base + TIMER_CTRL_OFF); |
239 | writel(u & ~(TIMER0_25MHZ), |
240 | local_base + TIMER_CTRL_OFF); |
241 | |
242 | u = readl(timer_base + TIMER_CTRL_OFF); |
243 | writel(u & ~(TIMER0_25MHZ), |
244 | timer_base + TIMER_CTRL_OFF); |
245 | |
246 | timer_clk = rate / TIMER_DIVIDER; |
247 | timer25Mhz = false; |
248 | } |
249 | |
250 | /* |
251 | * We use timer 0 as clocksource, and private(local) timer 0 |
252 | * for clockevents |
253 | */ |
254 | armada_370_xp_clkevt.irq = irq_of_parse_and_map(np, 4); |
255 | |
256 | ticks_per_jiffy = (timer_clk + HZ / 2) / HZ; |
257 | |
258 | /* |
259 | * Set scale and timer for sched_clock. |
260 | */ |
261 | setup_sched_clock(armada_370_xp_read_sched_clock, 32, timer_clk); |
262 | |
263 | /* |
264 | * Setup free-running clocksource timer (interrupts |
265 | * disabled). |
266 | */ |
267 | writel(0xffffffff, timer_base + TIMER0_VAL_OFF); |
268 | writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF); |
269 | |
270 | u = readl(timer_base + TIMER_CTRL_OFF); |
271 | |
272 | writel((u | TIMER0_EN | TIMER0_RELOAD_EN | |
273 | TIMER0_DIV(TIMER_DIVIDER_SHIFT)), timer_base + TIMER_CTRL_OFF); |
274 | |
275 | clocksource_mmio_init(timer_base + TIMER0_VAL_OFF, |
276 | "armada_370_xp_clocksource", |
277 | timer_clk, 300, 32, clocksource_mmio_readl_down); |
278 | |
279 | /* Register the clockevent on the private timer of CPU 0 */ |
280 | armada_370_xp_clkevt.cpumask = cpumask_of(0); |
281 | clockevents_config_and_register(&armada_370_xp_clkevt, |
282 | timer_clk, 1, 0xfffffffe); |
283 | |
284 | percpu_armada_370_xp_evt = alloc_percpu(struct clock_event_device *); |
285 | |
286 | |
287 | /* |
288 | * Setup clockevent timer (interrupt-driven). |
289 | */ |
290 | *__this_cpu_ptr(percpu_armada_370_xp_evt) = &armada_370_xp_clkevt; |
291 | res = request_percpu_irq(armada_370_xp_clkevt.irq, |
292 | armada_370_xp_timer_interrupt, |
293 | armada_370_xp_clkevt.name, |
294 | percpu_armada_370_xp_evt); |
295 | if (!res) { |
296 | enable_percpu_irq(armada_370_xp_clkevt.irq, 0); |
297 | #ifdef CONFIG_LOCAL_TIMERS |
298 | local_timer_register(&armada_370_xp_local_timer_ops); |
299 | #endif |
300 | } |
301 | } |
302 |
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