a62e9030 |
1 | /* |
2 | * linux/arch/arm/mach-nuc93x/time.c |
3 | * |
4 | * Copyright (c) 2009 Nuvoton technology corporation. |
5 | * |
6 | * Wan ZongShun <mcuos.com@gmail.com> |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify |
9 | * it under the terms of the GNU General Public License as published by |
10 | * the Free Software Foundation; either version 2 of the License, or |
11 | * (at your option) any later version. |
12 | * |
13 | */ |
14 | |
15 | #include <linux/kernel.h> |
16 | #include <linux/sched.h> |
17 | #include <linux/init.h> |
18 | #include <linux/interrupt.h> |
19 | #include <linux/err.h> |
20 | #include <linux/clk.h> |
21 | #include <linux/io.h> |
22 | #include <linux/leds.h> |
23 | |
24 | #include <asm/mach-types.h> |
25 | #include <asm/mach/irq.h> |
26 | #include <asm/mach/time.h> |
27 | |
28 | #include <mach/system.h> |
29 | #include <mach/map.h> |
30 | #include <mach/regs-timer.h> |
31 | |
32 | #define RESETINT 0x01 |
33 | #define PERIOD (0x01 << 27) |
34 | #define ONESHOT (0x00 << 27) |
35 | #define COUNTEN (0x01 << 30) |
36 | #define INTEN (0x01 << 29) |
37 | |
38 | #define TICKS_PER_SEC 100 |
39 | #define PRESCALE 0x63 /* Divider = prescale + 1 */ |
40 | |
41 | unsigned int timer0_load; |
42 | |
43 | static unsigned long nuc93x_gettimeoffset(void) |
44 | { |
45 | return 0; |
46 | } |
47 | |
48 | /*IRQ handler for the timer*/ |
49 | |
50 | static irqreturn_t nuc93x_timer_interrupt(int irq, void *dev_id) |
51 | { |
52 | timer_tick(); |
53 | __raw_writel(0x01, REG_TISR); /* clear TIF0 */ |
54 | return IRQ_HANDLED; |
55 | } |
56 | |
57 | static struct irqaction nuc93x_timer_irq = { |
58 | .name = "nuc93x Timer Tick", |
59 | .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, |
60 | .handler = nuc93x_timer_interrupt, |
61 | }; |
62 | |
63 | /*Set up timer reg.*/ |
64 | |
65 | static void nuc93x_timer_setup(void) |
66 | { |
67 | struct clk *ck_ext = clk_get(NULL, "ext"); |
68 | struct clk *ck_timer = clk_get(NULL, "timer"); |
69 | unsigned int rate, val = 0; |
70 | |
71 | BUG_ON(IS_ERR(ck_ext) || IS_ERR(ck_timer)); |
72 | |
73 | clk_enable(ck_timer); |
74 | rate = clk_get_rate(ck_ext); |
75 | clk_put(ck_ext); |
76 | rate = rate / (PRESCALE + 0x01); |
77 | |
78 | /* set a known state */ |
79 | __raw_writel(0x00, REG_TCSR0); |
80 | __raw_writel(RESETINT, REG_TISR); |
81 | |
82 | timer0_load = (rate / TICKS_PER_SEC); |
83 | __raw_writel(timer0_load, REG_TICR0); |
84 | |
85 | val |= (PERIOD | COUNTEN | INTEN | PRESCALE);; |
86 | __raw_writel(val, REG_TCSR0); |
87 | |
88 | } |
89 | |
90 | static void __init nuc93x_timer_init(void) |
91 | { |
92 | nuc93x_timer_setup(); |
93 | setup_irq(IRQ_TIMER0, &nuc93x_timer_irq); |
94 | } |
95 | |
96 | struct sys_timer nuc93x_timer = { |
97 | .init = nuc93x_timer_init, |
98 | .offset = nuc93x_gettimeoffset, |
99 | .resume = nuc93x_timer_setup |
100 | }; |