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author | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-22 14:22:59 -0400 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-22 14:22:59 -0400 |
commit | 7578634990fb47cc30083fbd812689aa6deacfc0 (patch) | |
tree | f493860658579d9572a19b3a41fcea2de035e49f /arch/arm/mach-mx3/time.c | |
parent | d7f5e3df3574c6e38b99f5fe22f15540b2b9811d (diff) | |
parent | 5957a4eb284dd6f522b248b674792416466555b2 (diff) |
Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: (60 commits)
[ARM] 4524/1: S3C: Move register out of include/asm-arm/arch-s3c2410
[ARM] 4523/1: S3C: Remove FIFO_MAX from uncompression headers
[ARM] 4522/1: S3C: split include/asm-arm/arch/memory.h
[ARM] 4521/2: S3C: Reorganise VA mapping headers
[ARM] 4520/1: S3C: Remove old VA values from static map
[ARM] 4519/1: S3C: split S3C2400 values out of S3C24XX map.h
[ARM] 4518/1: S3C: Rename watchdog configuration options
[ARM] 4517/1: S3C: Fix debug macros for ARM926 output
[ARM] 4516/1: S3C: Fix uncompressor serial output for ARM926
[ARM] 4515/1: S3C: Move uncompress code to plat-s3c
[ARM] 4514/1: S3C: Rename DEBUG_S3C2410_PORT and DEBUG_S3C_UART
[ARM] 4513/1: S3C: Rename CONFIG_S3C2410_LOWLEVEL_UART_PORT
[ARM] 4512/1: S3C: rename the debug macros for per-cpu updates
[ARM] 4511/1: S3C: updated LLSERIAL Kconfig defines for CPU support
[ARM] 4510/1: S3C: split debug-macro support into plat-s3c
[ARM] 4509/1: S3C: Create initial arch/arm/plat-s3c
[ARM] 4508/1: S3C: Move items to include/asm-arm/plat-s3c
[ARM] 4461/1: MXC platform and i.MX31ADS core support
[ARM] 4507/1: pxa2xx clock_event_device
[ARM] 4497/1: Only allow safe cache configurations on ARMv6 and later
...
Diffstat (limited to 'arch/arm/mach-mx3/time.c')
-rw-r--r-- | arch/arm/mach-mx3/time.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/arch/arm/mach-mx3/time.c b/arch/arm/mach-mx3/time.c new file mode 100644 index 000000000000..e81fb5c5d7c3 --- /dev/null +++ b/arch/arm/mach-mx3/time.c | |||
@@ -0,0 +1,152 @@ | |||
1 | /* | ||
2 | * System Timer Interrupt reconfigured to run in free-run mode. | ||
3 | * Author: Vitaly Wool | ||
4 | * Copyright 2004 MontaVista Software Inc. | ||
5 | * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved. | ||
6 | */ | ||
7 | |||
8 | /* | ||
9 | * This program is free software; you can redistribute it and/or modify | ||
10 | * it under the terms of the GNU General Public License version 2 as | ||
11 | * published by the Free Software Foundation. | ||
12 | */ | ||
13 | |||
14 | /*! | ||
15 | * @file time.c | ||
16 | * @brief This file contains OS tick and wdog timer implementations. | ||
17 | * | ||
18 | * This file contains OS tick and wdog timer implementations. | ||
19 | * | ||
20 | * @ingroup Timers | ||
21 | */ | ||
22 | |||
23 | #include <linux/module.h> | ||
24 | #include <linux/init.h> | ||
25 | #include <linux/interrupt.h> | ||
26 | #include <linux/irq.h> | ||
27 | #include <asm/hardware.h> | ||
28 | #include <asm/mach/time.h> | ||
29 | #include <asm/io.h> | ||
30 | #include <asm/arch/common.h> | ||
31 | |||
32 | /*! | ||
33 | * This is the timer interrupt service routine to do required tasks. | ||
34 | * It also services the WDOG timer at the frequency of twice per WDOG | ||
35 | * timeout value. For example, if the WDOG's timeout value is 4 (2 | ||
36 | * seconds since the WDOG runs at 0.5Hz), it will be serviced once | ||
37 | * every 2/2=1 second. | ||
38 | * | ||
39 | * @param irq GPT interrupt source number (not used) | ||
40 | * @param dev_id this parameter is not used | ||
41 | * @return always returns \b IRQ_HANDLED as defined in | ||
42 | * include/linux/interrupt.h. | ||
43 | */ | ||
44 | static irqreturn_t mxc_timer_interrupt(int irq, void *dev_id) | ||
45 | { | ||
46 | unsigned int next_match; | ||
47 | |||
48 | write_seqlock(&xtime_lock); | ||
49 | |||
50 | if (__raw_readl(MXC_GPT_GPTSR) & GPTSR_OF1) { | ||
51 | do { | ||
52 | timer_tick(); | ||
53 | next_match = __raw_readl(MXC_GPT_GPTOCR1) + LATCH; | ||
54 | __raw_writel(GPTSR_OF1, MXC_GPT_GPTSR); | ||
55 | __raw_writel(next_match, MXC_GPT_GPTOCR1); | ||
56 | } while ((signed long)(next_match - | ||
57 | __raw_readl(MXC_GPT_GPTCNT)) <= 0); | ||
58 | } | ||
59 | |||
60 | write_sequnlock(&xtime_lock); | ||
61 | |||
62 | return IRQ_HANDLED; | ||
63 | } | ||
64 | |||
65 | /*! | ||
66 | * This function is used to obtain the number of microseconds since the last | ||
67 | * timer interrupt. Note that interrupts is disabled by do_gettimeofday(). | ||
68 | * | ||
69 | * @return the number of microseconds since the last timer interrupt. | ||
70 | */ | ||
71 | static unsigned long mxc_gettimeoffset(void) | ||
72 | { | ||
73 | unsigned long ticks_to_match, elapsed, usec, tick_usec, i; | ||
74 | |||
75 | /* Get ticks before next timer match */ | ||
76 | ticks_to_match = | ||
77 | __raw_readl(MXC_GPT_GPTOCR1) - __raw_readl(MXC_GPT_GPTCNT); | ||
78 | |||
79 | /* We need elapsed ticks since last match */ | ||
80 | elapsed = LATCH - ticks_to_match; | ||
81 | |||
82 | /* Now convert them to usec */ | ||
83 | /* Insure no overflow when calculating the usec below */ | ||
84 | for (i = 1, tick_usec = tick_nsec / 1000;; i *= 2) { | ||
85 | tick_usec /= i; | ||
86 | if ((0xFFFFFFFF / tick_usec) > elapsed) | ||
87 | break; | ||
88 | } | ||
89 | usec = (unsigned long)(elapsed * tick_usec) / (LATCH / i); | ||
90 | |||
91 | return usec; | ||
92 | } | ||
93 | |||
94 | /*! | ||
95 | * The OS tick timer interrupt structure. | ||
96 | */ | ||
97 | static struct irqaction timer_irq = { | ||
98 | .name = "MXC Timer Tick", | ||
99 | .flags = IRQF_DISABLED | IRQF_TIMER, | ||
100 | .handler = mxc_timer_interrupt | ||
101 | }; | ||
102 | |||
103 | /*! | ||
104 | * This function is used to initialize the GPT to produce an interrupt | ||
105 | * based on HZ. It is called by start_kernel() during system startup. | ||
106 | */ | ||
107 | void __init mxc_init_time(void) | ||
108 | { | ||
109 | u32 reg, v; | ||
110 | reg = __raw_readl(MXC_GPT_GPTCR); | ||
111 | reg &= ~GPTCR_ENABLE; | ||
112 | __raw_writel(reg, MXC_GPT_GPTCR); | ||
113 | reg |= GPTCR_SWR; | ||
114 | __raw_writel(reg, MXC_GPT_GPTCR); | ||
115 | |||
116 | while ((__raw_readl(MXC_GPT_GPTCR) & GPTCR_SWR) != 0) | ||
117 | cpu_relax(); | ||
118 | |||
119 | reg = GPTCR_FRR | GPTCR_CLKSRC_HIGHFREQ; | ||
120 | __raw_writel(reg, MXC_GPT_GPTCR); | ||
121 | |||
122 | /* TODO: get timer rate from clk driver */ | ||
123 | v = 66500000; | ||
124 | |||
125 | __raw_writel((v / CLOCK_TICK_RATE) - 1, MXC_GPT_GPTPR); | ||
126 | |||
127 | if ((v % CLOCK_TICK_RATE) != 0) { | ||
128 | pr_info("\nWARNING: Can't generate CLOCK_TICK_RATE at %d Hz\n", | ||
129 | CLOCK_TICK_RATE); | ||
130 | } | ||
131 | pr_info("Actual CLOCK_TICK_RATE is %d Hz\n", | ||
132 | v / ((__raw_readl(MXC_GPT_GPTPR) & 0xFFF) + 1)); | ||
133 | |||
134 | reg = __raw_readl(MXC_GPT_GPTCNT); | ||
135 | reg += LATCH; | ||
136 | __raw_writel(reg, MXC_GPT_GPTOCR1); | ||
137 | |||
138 | setup_irq(MXC_INT_GPT, &timer_irq); | ||
139 | |||
140 | reg = __raw_readl(MXC_GPT_GPTCR); | ||
141 | reg = | ||
142 | GPTCR_FRR | GPTCR_CLKSRC_HIGHFREQ | GPTCR_STOPEN | GPTCR_DOZEN | | ||
143 | GPTCR_WAITEN | GPTCR_ENMOD | GPTCR_ENABLE; | ||
144 | __raw_writel(reg, MXC_GPT_GPTCR); | ||
145 | |||
146 | __raw_writel(GPTIR_OF1IE, MXC_GPT_GPTIR); | ||
147 | } | ||
148 | |||
149 | struct sys_timer mxc_timer = { | ||
150 | .init = mxc_init_time, | ||
151 | .offset = mxc_gettimeoffset, | ||
152 | }; | ||