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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 * Clocksource driver for Armada 370 and Armada XP SoC.
19 * This driver implements one compatible string for each SoC, given
20 * each has its own characteristics:
21 *
22 * * Armada 370 has no 25 MHz fixed timer.
23 *
24 * * Armada XP cannot work properly without such 25 MHz fixed timer as
25 * doing otherwise leads to using a clocksource whose frequency varies
26 * when doing cpufreq frequency changes.
27 *
28 * See Documentation/devicetree/bindings/timer/marvell,armada-370-xp-timer.txt
29 */
30
31#include <linux/init.h>
32#include <linux/platform_device.h>
33#include <linux/kernel.h>
34#include <linux/clk.h>
35#include <linux/cpu.h>
36#include <linux/timer.h>
37#include <linux/clockchips.h>
38#include <linux/interrupt.h>
39#include <linux/of.h>
40#include <linux/of_irq.h>
41#include <linux/of_address.h>
42#include <linux/irq.h>
43#include <linux/module.h>
44#include <linux/sched_clock.h>
45#include <linux/percpu.h>
46#include <linux/syscore_ops.h>
47
48#include <asm/delay.h>
49
50/*
51 * Timer block registers.
52 */
53#define TIMER_CTRL_OFF 0x0000
54#define TIMER0_EN BIT(0)
55#define TIMER0_RELOAD_EN BIT(1)
56#define TIMER0_25MHZ BIT(11)
57#define TIMER0_DIV(div) ((div) << 19)
58#define TIMER1_EN BIT(2)
59#define TIMER1_RELOAD_EN BIT(3)
60#define TIMER1_25MHZ BIT(12)
61#define TIMER1_DIV(div) ((div) << 22)
62#define TIMER_EVENTS_STATUS 0x0004
63#define TIMER0_CLR_MASK (~0x1)
64#define TIMER1_CLR_MASK (~0x100)
65#define TIMER0_RELOAD_OFF 0x0010
66#define TIMER0_VAL_OFF 0x0014
67#define TIMER1_RELOAD_OFF 0x0018
68#define TIMER1_VAL_OFF 0x001c
69
70#define LCL_TIMER_EVENTS_STATUS 0x0028
71/* Global timers are connected to the coherency fabric clock, and the
72 below divider reduces their incrementing frequency. */
73#define TIMER_DIVIDER_SHIFT 5
74#define TIMER_DIVIDER (1 << TIMER_DIVIDER_SHIFT)
75
76/*
77 * SoC-specific data.
78 */
79static void __iomem *timer_base, *local_base;
80static unsigned int timer_clk;
81static bool timer25Mhz = true;
82static u32 enable_mask;
83
84/*
85 * Number of timer ticks per jiffy.
86 */
87static u32 ticks_per_jiffy;
88
89static struct clock_event_device __percpu *armada_370_xp_evt;
90
91static void local_timer_ctrl_clrset(u32 clr, u32 set)
92{
93 writel((readl(local_base + TIMER_CTRL_OFF) & ~clr) | set,
94 local_base + TIMER_CTRL_OFF);
95}
96
97static u64 notrace armada_370_xp_read_sched_clock(void)
98{
99 return ~readl(timer_base + TIMER0_VAL_OFF);
100}
101
102/*
103 * Clockevent handling.
104 */
105static int
106armada_370_xp_clkevt_next_event(unsigned long delta,
107 struct clock_event_device *dev)
108{
109 /*
110 * Clear clockevent timer interrupt.
111 */
112 writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
113
114 /*
115 * Setup new clockevent timer value.
116 */
117 writel(delta, local_base + TIMER0_VAL_OFF);
118
119 /*
120 * Enable the timer.
121 */
122 local_timer_ctrl_clrset(TIMER0_RELOAD_EN, enable_mask);
123 return 0;
124}
125
126static int armada_370_xp_clkevt_shutdown(struct clock_event_device *evt)
127{
128 /*
129 * Disable timer.
130 */
131 local_timer_ctrl_clrset(TIMER0_EN, 0);
132
133 /*
134 * ACK pending timer interrupt.
135 */
136 writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
137 return 0;
138}
139
140static int armada_370_xp_clkevt_set_periodic(struct clock_event_device *evt)
141{
142 /*
143 * Setup timer to fire at 1/HZ intervals.
144 */
145 writel(ticks_per_jiffy - 1, local_base + TIMER0_RELOAD_OFF);
146 writel(ticks_per_jiffy - 1, local_base + TIMER0_VAL_OFF);
147
148 /*
149 * Enable timer.
150 */
151 local_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | enable_mask);
152 return 0;
153}
154
155static int armada_370_xp_clkevt_irq;
156
157static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id)
158{
159 /*
160 * ACK timer interrupt and call event handler.
161 */
162 struct clock_event_device *evt = dev_id;
163
164 writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
165 evt->event_handler(evt);
166
167 return IRQ_HANDLED;
168}
169
170/*
171 * Setup the local clock events for a CPU.
172 */
173static int armada_370_xp_timer_setup(struct clock_event_device *evt)
174{
175 u32 clr = 0, set = 0;
176 int cpu = smp_processor_id();
177
178 if (timer25Mhz)
179 set = TIMER0_25MHZ;
180 else
181 clr = TIMER0_25MHZ;
182 local_timer_ctrl_clrset(clr, set);
183
184 evt->name = "armada_370_xp_per_cpu_tick",
185 evt->features = CLOCK_EVT_FEAT_ONESHOT |
186 CLOCK_EVT_FEAT_PERIODIC;
187 evt->shift = 32,
188 evt->rating = 300,
189 evt->set_next_event = armada_370_xp_clkevt_next_event,
190 evt->set_state_shutdown = armada_370_xp_clkevt_shutdown;
191 evt->set_state_periodic = armada_370_xp_clkevt_set_periodic;
192 evt->set_state_oneshot = armada_370_xp_clkevt_shutdown;
193 evt->tick_resume = armada_370_xp_clkevt_shutdown;
194 evt->irq = armada_370_xp_clkevt_irq;
195 evt->cpumask = cpumask_of(cpu);
196
197 clockevents_config_and_register(evt, timer_clk, 1, 0xfffffffe);
198 enable_percpu_irq(evt->irq, 0);
199
200 return 0;
201}
202
203static void armada_370_xp_timer_stop(struct clock_event_device *evt)
204{
205 evt->set_state_shutdown(evt);
206 disable_percpu_irq(evt->irq);
207}
208
209static int armada_370_xp_timer_cpu_notify(struct notifier_block *self,
210 unsigned long action, void *hcpu)
211{
212 /*
213 * Grab cpu pointer in each case to avoid spurious
214 * preemptible warnings
215 */
216 switch (action & ~CPU_TASKS_FROZEN) {
217 case CPU_STARTING:
218 armada_370_xp_timer_setup(this_cpu_ptr(armada_370_xp_evt));
219 break;
220 case CPU_DYING:
221 armada_370_xp_timer_stop(this_cpu_ptr(armada_370_xp_evt));
222 break;
223 }
224
225 return NOTIFY_OK;
226}
227
228static struct notifier_block armada_370_xp_timer_cpu_nb = {
229 .notifier_call = armada_370_xp_timer_cpu_notify,
230};
231
232static u32 timer0_ctrl_reg, timer0_local_ctrl_reg;
233
234static int armada_370_xp_timer_suspend(void)
235{
236 timer0_ctrl_reg = readl(timer_base + TIMER_CTRL_OFF);
237 timer0_local_ctrl_reg = readl(local_base + TIMER_CTRL_OFF);
238 return 0;
239}
240
241static void armada_370_xp_timer_resume(void)
242{
243 writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
244 writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
245 writel(timer0_ctrl_reg, timer_base + TIMER_CTRL_OFF);
246 writel(timer0_local_ctrl_reg, local_base + TIMER_CTRL_OFF);
247}
248
249struct syscore_ops armada_370_xp_timer_syscore_ops = {
250 .suspend = armada_370_xp_timer_suspend,
251 .resume = armada_370_xp_timer_resume,
252};
253
254static unsigned long armada_370_delay_timer_read(void)
255{
256 return ~readl(timer_base + TIMER0_VAL_OFF);
257}
258
259static struct delay_timer armada_370_delay_timer = {
260 .read_current_timer = armada_370_delay_timer_read,
261};
262
263static void __init armada_370_xp_timer_common_init(struct device_node *np)
264{
265 u32 clr = 0, set = 0;
266 int res;
267
268 timer_base = of_iomap(np, 0);
269 WARN_ON(!timer_base);
270 local_base = of_iomap(np, 1);
271
272 if (timer25Mhz) {
273 set = TIMER0_25MHZ;
274 enable_mask = TIMER0_EN;
275 } else {
276 clr = TIMER0_25MHZ;
277 enable_mask = TIMER0_EN | TIMER0_DIV(TIMER_DIVIDER_SHIFT);
278 }
279 atomic_io_modify(timer_base + TIMER_CTRL_OFF, clr | set, set);
280 local_timer_ctrl_clrset(clr, set);
281
282 /*
283 * We use timer 0 as clocksource, and private(local) timer 0
284 * for clockevents
285 */
286 armada_370_xp_clkevt_irq = irq_of_parse_and_map(np, 4);
287
288 ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
289
290 /*
291 * Setup free-running clocksource timer (interrupts
292 * disabled).
293 */
294 writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
295 writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
296
297 atomic_io_modify(timer_base + TIMER_CTRL_OFF,
298 TIMER0_RELOAD_EN | enable_mask,
299 TIMER0_RELOAD_EN | enable_mask);
300
301 armada_370_delay_timer.freq = timer_clk;
302 register_current_timer_delay(&armada_370_delay_timer);
303
304 /*
305 * Set scale and timer for sched_clock.
306 */
307 sched_clock_register(armada_370_xp_read_sched_clock, 32, timer_clk);
308
309 clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
310 "armada_370_xp_clocksource",
311 timer_clk, 300, 32, clocksource_mmio_readl_down);
312
313 register_cpu_notifier(&armada_370_xp_timer_cpu_nb);
314
315 armada_370_xp_evt = alloc_percpu(struct clock_event_device);
316
317
318 /*
319 * Setup clockevent timer (interrupt-driven).
320 */
321 res = request_percpu_irq(armada_370_xp_clkevt_irq,
322 armada_370_xp_timer_interrupt,
323 "armada_370_xp_per_cpu_tick",
324 armada_370_xp_evt);
325 /* Immediately configure the timer on the boot CPU */
326 if (!res)
327 armada_370_xp_timer_setup(this_cpu_ptr(armada_370_xp_evt));
328
329 register_syscore_ops(&armada_370_xp_timer_syscore_ops);
330}
331
332static void __init armada_xp_timer_init(struct device_node *np)
333{
334 struct clk *clk = of_clk_get_by_name(np, "fixed");
335
336 /* The 25Mhz fixed clock is mandatory, and must always be available */
337 BUG_ON(IS_ERR(clk));
338 clk_prepare_enable(clk);
339 timer_clk = clk_get_rate(clk);
340
341 armada_370_xp_timer_common_init(np);
342}
343CLOCKSOURCE_OF_DECLARE(armada_xp, "marvell,armada-xp-timer",
344 armada_xp_timer_init);
345
346static void __init armada_375_timer_init(struct device_node *np)
347{
348 struct clk *clk;
349
350 clk = of_clk_get_by_name(np, "fixed");
351 if (!IS_ERR(clk)) {
352 clk_prepare_enable(clk);
353 timer_clk = clk_get_rate(clk);
354 } else {
355
356 /*
357 * This fallback is required in order to retain proper
358 * devicetree backwards compatibility.
359 */
360 clk = of_clk_get(np, 0);
361
362 /* Must have at least a clock */
363 BUG_ON(IS_ERR(clk));
364 clk_prepare_enable(clk);
365 timer_clk = clk_get_rate(clk) / TIMER_DIVIDER;
366 timer25Mhz = false;
367 }
368
369 armada_370_xp_timer_common_init(np);
370}
371CLOCKSOURCE_OF_DECLARE(armada_375, "marvell,armada-375-timer",
372 armada_375_timer_init);
373
374static void __init armada_370_timer_init(struct device_node *np)
375{
376 struct clk *clk = of_clk_get(np, 0);
377
378 BUG_ON(IS_ERR(clk));
379 clk_prepare_enable(clk);
380 timer_clk = clk_get_rate(clk) / TIMER_DIVIDER;
381 timer25Mhz = false;
382
383 armada_370_xp_timer_common_init(np);
384}
385CLOCKSOURCE_OF_DECLARE(armada_370, "marvell,armada-370-timer",
386 armada_370_timer_init);