diff options
author | Russell King <rmk@dyn-67.arm.linux.org.uk> | 2009-09-12 07:02:26 -0400 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-09-12 07:02:26 -0400 |
commit | ddd559b13f6d2fe3ad68c4b3f5235fd3c2eae4e3 (patch) | |
tree | d827bca3fc825a0ac33efbcd493713be40fcc812 /arch/arm/mach-nomadik/timer.c | |
parent | cf7a2b4fb6a9b86779930a0a123b0df41aa9208f (diff) | |
parent | f17a1f06d2fa93f4825be572622eb02c4894db4e (diff) |
Merge branch 'devel-stable' into devel
Conflicts:
MAINTAINERS
arch/arm/mm/fault.c
Diffstat (limited to 'arch/arm/mach-nomadik/timer.c')
-rw-r--r-- | arch/arm/mach-nomadik/timer.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/arch/arm/mach-nomadik/timer.c b/arch/arm/mach-nomadik/timer.c new file mode 100644 index 000000000000..d1738e7061d4 --- /dev/null +++ b/arch/arm/mach-nomadik/timer.c | |||
@@ -0,0 +1,164 @@ | |||
1 | /* | ||
2 | * linux/arch/arm/mach-nomadik/timer.c | ||
3 | * | ||
4 | * Copyright (C) 2008 STMicroelectronics | ||
5 | * Copyright (C) 2009 Alessandro Rubini, somewhat based on at91sam926x | ||
6 | * | ||
7 | * This program is free software; you can redistribute it and/or modify | ||
8 | * it under the terms of the GNU General Public License version 2, as | ||
9 | * published by the Free Software Foundation. | ||
10 | */ | ||
11 | #include <linux/init.h> | ||
12 | #include <linux/interrupt.h> | ||
13 | #include <linux/irq.h> | ||
14 | #include <linux/io.h> | ||
15 | #include <linux/clockchips.h> | ||
16 | #include <linux/jiffies.h> | ||
17 | #include <asm/mach/time.h> | ||
18 | #include <mach/mtu.h> | ||
19 | |||
20 | #define TIMER_CTRL 0x80 /* No divisor */ | ||
21 | #define TIMER_PERIODIC 0x40 | ||
22 | #define TIMER_SZ32BIT 0x02 | ||
23 | |||
24 | /* Initial value for SRC control register: all timers use MXTAL/8 source */ | ||
25 | #define SRC_CR_INIT_MASK 0x00007fff | ||
26 | #define SRC_CR_INIT_VAL 0x2aaa8000 | ||
27 | |||
28 | static u32 nmdk_count; /* accumulated count */ | ||
29 | static u32 nmdk_cycle; /* write-once */ | ||
30 | static __iomem void *mtu_base; | ||
31 | |||
32 | /* | ||
33 | * clocksource: the MTU device is a decrementing counters, so we negate | ||
34 | * the value being read. | ||
35 | */ | ||
36 | static cycle_t nmdk_read_timer(struct clocksource *cs) | ||
37 | { | ||
38 | u32 count = readl(mtu_base + MTU_VAL(0)); | ||
39 | return nmdk_count + nmdk_cycle - count; | ||
40 | |||
41 | } | ||
42 | |||
43 | static struct clocksource nmdk_clksrc = { | ||
44 | .name = "mtu_0", | ||
45 | .rating = 120, | ||
46 | .read = nmdk_read_timer, | ||
47 | .shift = 20, | ||
48 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | ||
49 | }; | ||
50 | |||
51 | /* | ||
52 | * Clockevent device: currently only periodic mode is supported | ||
53 | */ | ||
54 | static void nmdk_clkevt_mode(enum clock_event_mode mode, | ||
55 | struct clock_event_device *dev) | ||
56 | { | ||
57 | unsigned long flags; | ||
58 | |||
59 | switch (mode) { | ||
60 | case CLOCK_EVT_MODE_PERIODIC: | ||
61 | /* enable interrupts -- and count current value? */ | ||
62 | raw_local_irq_save(flags); | ||
63 | writel(readl(mtu_base + MTU_IMSC) | 1, mtu_base + MTU_IMSC); | ||
64 | raw_local_irq_restore(flags); | ||
65 | break; | ||
66 | case CLOCK_EVT_MODE_ONESHOT: | ||
67 | BUG(); /* Not supported, yet */ | ||
68 | /* FALLTHROUGH */ | ||
69 | case CLOCK_EVT_MODE_SHUTDOWN: | ||
70 | case CLOCK_EVT_MODE_UNUSED: | ||
71 | /* disable irq */ | ||
72 | raw_local_irq_save(flags); | ||
73 | writel(readl(mtu_base + MTU_IMSC) & ~1, mtu_base + MTU_IMSC); | ||
74 | raw_local_irq_restore(flags); | ||
75 | break; | ||
76 | case CLOCK_EVT_MODE_RESUME: | ||
77 | break; | ||
78 | } | ||
79 | } | ||
80 | |||
81 | static struct clock_event_device nmdk_clkevt = { | ||
82 | .name = "mtu_0", | ||
83 | .features = CLOCK_EVT_FEAT_PERIODIC, | ||
84 | .shift = 32, | ||
85 | .rating = 100, | ||
86 | .set_mode = nmdk_clkevt_mode, | ||
87 | }; | ||
88 | |||
89 | /* | ||
90 | * IRQ Handler for the timer 0 of the MTU block. The irq is not shared | ||
91 | * as we are the only users of mtu0 by now. | ||
92 | */ | ||
93 | static irqreturn_t nmdk_timer_interrupt(int irq, void *dev_id) | ||
94 | { | ||
95 | /* ack: "interrupt clear register" */ | ||
96 | writel( 1 << 0, mtu_base + MTU_ICR); | ||
97 | |||
98 | /* we can't count lost ticks, unfortunately */ | ||
99 | nmdk_count += nmdk_cycle; | ||
100 | nmdk_clkevt.event_handler(&nmdk_clkevt); | ||
101 | |||
102 | return IRQ_HANDLED; | ||
103 | } | ||
104 | |||
105 | /* | ||
106 | * Set up timer interrupt, and return the current time in seconds. | ||
107 | */ | ||
108 | static struct irqaction nmdk_timer_irq = { | ||
109 | .name = "Nomadik Timer Tick", | ||
110 | .flags = IRQF_DISABLED | IRQF_TIMER, | ||
111 | .handler = nmdk_timer_interrupt, | ||
112 | }; | ||
113 | |||
114 | static void nmdk_timer_reset(void) | ||
115 | { | ||
116 | u32 cr; | ||
117 | |||
118 | writel(0, mtu_base + MTU_CR(0)); /* off */ | ||
119 | |||
120 | /* configure load and background-load, and fire it up */ | ||
121 | writel(nmdk_cycle, mtu_base + MTU_LR(0)); | ||
122 | writel(nmdk_cycle, mtu_base + MTU_BGLR(0)); | ||
123 | cr = MTU_CRn_PERIODIC | MTU_CRn_PRESCALE_1 | MTU_CRn_32BITS; | ||
124 | writel(cr, mtu_base + MTU_CR(0)); | ||
125 | writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0)); | ||
126 | } | ||
127 | |||
128 | static void __init nmdk_timer_init(void) | ||
129 | { | ||
130 | u32 src_cr; | ||
131 | unsigned long rate; | ||
132 | int bits; | ||
133 | |||
134 | rate = CLOCK_TICK_RATE; /* 2.4MHz */ | ||
135 | nmdk_cycle = (rate + HZ/2) / HZ; | ||
136 | |||
137 | /* Configure timer sources in "system reset controller" ctrl reg */ | ||
138 | src_cr = readl(io_p2v(NOMADIK_SRC_BASE)); | ||
139 | src_cr &= SRC_CR_INIT_MASK; | ||
140 | src_cr |= SRC_CR_INIT_VAL; | ||
141 | writel(src_cr, io_p2v(NOMADIK_SRC_BASE)); | ||
142 | |||
143 | /* Save global pointer to mtu, used by functions above */ | ||
144 | mtu_base = io_p2v(NOMADIK_MTU0_BASE); | ||
145 | |||
146 | /* Init the timer and register clocksource */ | ||
147 | nmdk_timer_reset(); | ||
148 | |||
149 | nmdk_clksrc.mult = clocksource_hz2mult(rate, nmdk_clksrc.shift); | ||
150 | bits = 8*sizeof(nmdk_count); | ||
151 | nmdk_clksrc.mask = CLOCKSOURCE_MASK(bits); | ||
152 | |||
153 | clocksource_register(&nmdk_clksrc); | ||
154 | |||
155 | /* Register irq and clockevents */ | ||
156 | setup_irq(IRQ_MTU0, &nmdk_timer_irq); | ||
157 | nmdk_clkevt.mult = div_sc(rate, NSEC_PER_SEC, nmdk_clkevt.shift); | ||
158 | nmdk_clkevt.cpumask = cpumask_of(0); | ||
159 | clockevents_register_device(&nmdk_clkevt); | ||
160 | } | ||
161 | |||
162 | struct sys_timer nomadik_timer = { | ||
163 | .init = nmdk_timer_init, | ||
164 | }; | ||