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Vitaly Wool78818e42006-05-16 11:54:37 +01001/*
2 * arch/arm/mach-pnx4008/time.c
3 *
4 * PNX4008 Timers
5 *
6 * Authors: Vitaly Wool, Dmitry Chigirev, Grigory Tolstolytkin <source@mvista.com>
7 *
8 * 2005 (c) MontaVista Software, Inc. This file is licensed under
9 * the terms of the GNU General Public License version 2. This program
10 * is licensed "as is" without any warranty of any kind, whether express
11 * or implied.
12 */
13
Vitaly Wool78818e42006-05-16 11:54:37 +010014#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/delay.h>
17#include <linux/interrupt.h>
18#include <linux/sched.h>
19#include <linux/spinlock.h>
20#include <linux/module.h>
21#include <linux/kallsyms.h>
Vitaly Wool5904a7f2006-07-05 14:47:20 +010022#include <linux/time.h>
23#include <linux/timex.h>
24#include <linux/irq.h>
Vitaly Wool78818e42006-05-16 11:54:37 +010025
26#include <asm/system.h>
27#include <asm/hardware.h>
28#include <asm/io.h>
29#include <asm/leds.h>
Vitaly Wool78818e42006-05-16 11:54:37 +010030#include <asm/mach/time.h>
Vitaly Wool78818e42006-05-16 11:54:37 +010031#include <asm/errno.h>
32
33/*! Note: all timers are UPCOUNTING */
34
35/*!
36 * Returns number of us since last clock interrupt. Note that interrupts
37 * will have been disabled by do_gettimeoffset()
38 */
39static unsigned long pnx4008_gettimeoffset(void)
40{
41 u32 ticks_to_match =
42 __raw_readl(HSTIM_MATCH0) - __raw_readl(HSTIM_COUNTER);
43 u32 elapsed = LATCH - ticks_to_match;
44 return (elapsed * (tick_nsec / 1000)) / LATCH;
45}
46
47/*!
48 * IRQ handler for the timer
49 */
Linus Torvalds0cd61b62006-10-06 10:53:39 -070050static irqreturn_t pnx4008_timer_interrupt(int irq, void *dev_id)
Vitaly Wool78818e42006-05-16 11:54:37 +010051{
52 if (__raw_readl(HSTIM_INT) & MATCH0_INT) {
53
Vitaly Wool78818e42006-05-16 11:54:37 +010054 do {
Linus Torvalds0cd61b62006-10-06 10:53:39 -070055 timer_tick();
Vitaly Wool78818e42006-05-16 11:54:37 +010056
57 /*
58 * this algorithm takes care of possible delay
59 * for this interrupt handling longer than a normal
60 * timer period
61 */
62 __raw_writel(__raw_readl(HSTIM_MATCH0) + LATCH,
63 HSTIM_MATCH0);
64 __raw_writel(MATCH0_INT, HSTIM_INT); /* clear interrupt */
65
66 /*
67 * The goal is to keep incrementing HSTIM_MATCH0
68 * register until HSTIM_MATCH0 indicates time after
69 * what HSTIM_COUNTER indicates.
70 */
71 } while ((signed)
72 (__raw_readl(HSTIM_MATCH0) -
73 __raw_readl(HSTIM_COUNTER)) < 0);
Vitaly Wool78818e42006-05-16 11:54:37 +010074 }
75
76 return IRQ_HANDLED;
77}
78
79static struct irqaction pnx4008_timer_irq = {
80 .name = "PNX4008 Tick Timer",
Bernhard Walleb30faba2007-05-08 00:35:39 -070081 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
Vitaly Wool78818e42006-05-16 11:54:37 +010082 .handler = pnx4008_timer_interrupt
83};
84
85/*!
86 * Set up timer and timer interrupt.
87 */
88static __init void pnx4008_setup_timer(void)
89{
90 __raw_writel(RESET_COUNT, MSTIM_CTRL);
91 while (__raw_readl(MSTIM_COUNTER)) ; /* wait for reset to complete. 100% guarantee event */
92 __raw_writel(0, MSTIM_CTRL); /* stop the timer */
93 __raw_writel(0, MSTIM_MCTRL);
94
95 __raw_writel(RESET_COUNT, HSTIM_CTRL);
96 while (__raw_readl(HSTIM_COUNTER)) ; /* wait for reset to complete. 100% guarantee event */
97 __raw_writel(0, HSTIM_CTRL);
98 __raw_writel(0, HSTIM_MCTRL);
99 __raw_writel(0, HSTIM_CCR);
100 __raw_writel(12, HSTIM_PMATCH); /* scale down to 1 MHZ */
101 __raw_writel(LATCH, HSTIM_MATCH0);
102 __raw_writel(MR0_INT, HSTIM_MCTRL);
103
104 setup_irq(HSTIMER_INT, &pnx4008_timer_irq);
105
106 __raw_writel(COUNT_ENAB | DEBUG_EN, HSTIM_CTRL); /*start timer, stop when JTAG active */
107}
108
109/* Timer Clock Control in PM register */
110#define TIMCLK_CTRL_REG IO_ADDRESS((PNX4008_PWRMAN_BASE + 0xBC))
111#define WATCHDOG_CLK_EN 1
112#define TIMER_CLK_EN 2 /* HS and MS timers? */
113
114static u32 timclk_ctrl_reg_save;
115
116void pnx4008_timer_suspend(void)
117{
118 timclk_ctrl_reg_save = __raw_readl(TIMCLK_CTRL_REG);
119 __raw_writel(0, TIMCLK_CTRL_REG); /* disable timers */
120}
121
122void pnx4008_timer_resume(void)
123{
124 __raw_writel(timclk_ctrl_reg_save, TIMCLK_CTRL_REG); /* enable timers */
125}
126
127struct sys_timer pnx4008_timer = {
128 .init = pnx4008_setup_timer,
129 .offset = pnx4008_gettimeoffset,
130 .suspend = pnx4008_timer_suspend,
131 .resume = pnx4008_timer_resume,
132};
133