avoid endless loops in lib/swiotlb.c
[wrt350n-kernel.git] / arch / arm / mach-msm / timer.c
blobbd4732d1ab3eea55159334d54ef66578088cfcd3
1 /* linux/arch/arm/mach-msm/timer.c
3 * Copyright (C) 2007 Google, Inc.
5 * This software is licensed under the terms of the GNU General Public
6 * License version 2, as published by the Free Software Foundation, and
7 * may be copied, distributed, and modified under those terms.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
16 #include <linux/init.h>
17 #include <linux/time.h>
18 #include <linux/interrupt.h>
19 #include <linux/irq.h>
20 #include <linux/clk.h>
21 #include <linux/clockchips.h>
22 #include <linux/delay.h>
24 #include <asm/mach/time.h>
25 #include <asm/arch/msm_iomap.h>
27 #include <asm/io.h>
29 #define MSM_DGT_BASE (MSM_GPT_BASE + 0x10)
30 #define MSM_DGT_SHIFT (5)
32 #define TIMER_MATCH_VAL 0x0000
33 #define TIMER_COUNT_VAL 0x0004
34 #define TIMER_ENABLE 0x0008
35 #define TIMER_ENABLE_CLR_ON_MATCH_EN 2
36 #define TIMER_ENABLE_EN 1
37 #define TIMER_CLEAR 0x000C
39 #define CSR_PROTECTION 0x0020
40 #define CSR_PROTECTION_EN 1
42 #define GPT_HZ 32768
43 #define DGT_HZ 19200000 /* 19.2 MHz or 600 KHz after shift */
45 struct msm_clock {
46 struct clock_event_device clockevent;
47 struct clocksource clocksource;
48 struct irqaction irq;
49 uint32_t regbase;
50 uint32_t freq;
51 uint32_t shift;
54 static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
56 struct clock_event_device *evt = dev_id;
57 evt->event_handler(evt);
58 return IRQ_HANDLED;
61 static cycle_t msm_gpt_read(void)
63 return readl(MSM_GPT_BASE + TIMER_COUNT_VAL);
66 static cycle_t msm_dgt_read(void)
68 return readl(MSM_DGT_BASE + TIMER_COUNT_VAL) >> MSM_DGT_SHIFT;
71 static int msm_timer_set_next_event(unsigned long cycles,
72 struct clock_event_device *evt)
74 struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
75 uint32_t now = readl(clock->regbase + TIMER_COUNT_VAL);
76 uint32_t alarm = now + (cycles << clock->shift);
77 int late;
79 writel(alarm, clock->regbase + TIMER_MATCH_VAL);
80 now = readl(clock->regbase + TIMER_COUNT_VAL);
81 late = now - alarm;
82 if (late >= (-2 << clock->shift) && late < DGT_HZ*5) {
83 printk(KERN_NOTICE "msm_timer_set_next_event(%lu) clock %s, "
84 "alarm already expired, now %x, alarm %x, late %d\n",
85 cycles, clock->clockevent.name, now, alarm, late);
86 return -ETIME;
88 return 0;
91 static void msm_timer_set_mode(enum clock_event_mode mode,
92 struct clock_event_device *evt)
94 struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
95 switch (mode) {
96 case CLOCK_EVT_MODE_RESUME:
97 case CLOCK_EVT_MODE_PERIODIC:
98 break;
99 case CLOCK_EVT_MODE_ONESHOT:
100 writel(TIMER_ENABLE_EN, clock->regbase + TIMER_ENABLE);
101 break;
102 case CLOCK_EVT_MODE_UNUSED:
103 case CLOCK_EVT_MODE_SHUTDOWN:
104 writel(0, clock->regbase + TIMER_ENABLE);
105 break;
109 static struct msm_clock msm_clocks[] = {
111 .clockevent = {
112 .name = "gp_timer",
113 .features = CLOCK_EVT_FEAT_ONESHOT,
114 .shift = 32,
115 .rating = 200,
116 .set_next_event = msm_timer_set_next_event,
117 .set_mode = msm_timer_set_mode,
119 .clocksource = {
120 .name = "gp_timer",
121 .rating = 200,
122 .read = msm_gpt_read,
123 .mask = CLOCKSOURCE_MASK(32),
124 .shift = 24,
125 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
127 .irq = {
128 .name = "gp_timer",
129 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
130 .handler = msm_timer_interrupt,
131 .dev_id = &msm_clocks[0].clockevent,
132 .irq = INT_GP_TIMER_EXP
134 .regbase = MSM_GPT_BASE,
135 .freq = GPT_HZ
138 .clockevent = {
139 .name = "dg_timer",
140 .features = CLOCK_EVT_FEAT_ONESHOT,
141 .shift = 32 + MSM_DGT_SHIFT,
142 .rating = 300,
143 .set_next_event = msm_timer_set_next_event,
144 .set_mode = msm_timer_set_mode,
146 .clocksource = {
147 .name = "dg_timer",
148 .rating = 300,
149 .read = msm_dgt_read,
150 .mask = CLOCKSOURCE_MASK((32 - MSM_DGT_SHIFT)),
151 .shift = 24 - MSM_DGT_SHIFT,
152 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
154 .irq = {
155 .name = "dg_timer",
156 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
157 .handler = msm_timer_interrupt,
158 .dev_id = &msm_clocks[1].clockevent,
159 .irq = INT_DEBUG_TIMER_EXP
161 .regbase = MSM_DGT_BASE,
162 .freq = DGT_HZ >> MSM_DGT_SHIFT,
163 .shift = MSM_DGT_SHIFT
167 static void __init msm_timer_init(void)
169 int i;
170 int res;
172 for (i = 0; i < ARRAY_SIZE(msm_clocks); i++) {
173 struct msm_clock *clock = &msm_clocks[i];
174 struct clock_event_device *ce = &clock->clockevent;
175 struct clocksource *cs = &clock->clocksource;
176 writel(0, clock->regbase + TIMER_ENABLE);
177 writel(0, clock->regbase + TIMER_CLEAR);
178 writel(~0, clock->regbase + TIMER_MATCH_VAL);
180 ce->mult = div_sc(clock->freq, NSEC_PER_SEC, ce->shift);
181 /* allow at least 10 seconds to notice that the timer wrapped */
182 ce->max_delta_ns =
183 clockevent_delta2ns(0xf0000000 >> clock->shift, ce);
184 /* 4 gets rounded down to 3 */
185 ce->min_delta_ns = clockevent_delta2ns(4, ce);
186 ce->cpumask = cpumask_of_cpu(0);
188 cs->mult = clocksource_hz2mult(clock->freq, cs->shift);
189 res = clocksource_register(cs);
190 if (res)
191 printk(KERN_ERR "msm_timer_init: clocksource_register "
192 "failed for %s\n", cs->name);
194 res = setup_irq(clock->irq.irq, &clock->irq);
195 if (res)
196 printk(KERN_ERR "msm_timer_init: setup_irq "
197 "failed for %s\n", cs->name);
199 clockevents_register_device(ce);
203 struct sys_timer msm_timer = {
204 .init = msm_timer_init