xref: /OK3568_Linux_fs/u-boot/arch/arm/mach-versatile/timer.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun  * (C) Copyright 2003
3*4882a593Smuzhiyun  * Texas Instruments <www.ti.com>
4*4882a593Smuzhiyun  *
5*4882a593Smuzhiyun  * (C) Copyright 2002
6*4882a593Smuzhiyun  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
7*4882a593Smuzhiyun  * Marius Groeger <mgroeger@sysgo.de>
8*4882a593Smuzhiyun  *
9*4882a593Smuzhiyun  * (C) Copyright 2002
10*4882a593Smuzhiyun  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
11*4882a593Smuzhiyun  * Alex Zuepke <azu@sysgo.de>
12*4882a593Smuzhiyun  *
13*4882a593Smuzhiyun  * (C) Copyright 2002-2004
14*4882a593Smuzhiyun  * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
15*4882a593Smuzhiyun  *
16*4882a593Smuzhiyun  * (C) Copyright 2004
17*4882a593Smuzhiyun  * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
18*4882a593Smuzhiyun  *
19*4882a593Smuzhiyun  * SPDX-License-Identifier:	GPL-2.0+
20*4882a593Smuzhiyun  */
21*4882a593Smuzhiyun 
22*4882a593Smuzhiyun #include <common.h>
23*4882a593Smuzhiyun 
24*4882a593Smuzhiyun #define TIMER_ENABLE	(1 << 7)
25*4882a593Smuzhiyun #define TIMER_MODE_MSK	(1 << 6)
26*4882a593Smuzhiyun #define TIMER_MODE_FR	(0 << 6)
27*4882a593Smuzhiyun #define TIMER_MODE_PD	(1 << 6)
28*4882a593Smuzhiyun 
29*4882a593Smuzhiyun #define TIMER_INT_EN	(1 << 5)
30*4882a593Smuzhiyun #define TIMER_PRS_MSK	(3 << 2)
31*4882a593Smuzhiyun #define TIMER_PRS_8S	(1 << 3)
32*4882a593Smuzhiyun #define TIMER_SIZE_MSK	(1 << 2)
33*4882a593Smuzhiyun #define TIMER_ONE_SHT	(1 << 0)
34*4882a593Smuzhiyun 
timer_init(void)35*4882a593Smuzhiyun int timer_init (void)
36*4882a593Smuzhiyun {
37*4882a593Smuzhiyun 	ulong	tmr_ctrl_val;
38*4882a593Smuzhiyun 
39*4882a593Smuzhiyun 	/* 1st disable the Timer */
40*4882a593Smuzhiyun 	tmr_ctrl_val = *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8);
41*4882a593Smuzhiyun 	tmr_ctrl_val &= ~TIMER_ENABLE;
42*4882a593Smuzhiyun 	*(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = tmr_ctrl_val;
43*4882a593Smuzhiyun 
44*4882a593Smuzhiyun 	/*
45*4882a593Smuzhiyun 	 * The Timer Control Register has one Undefined/Shouldn't Use Bit
46*4882a593Smuzhiyun 	 * So we should do read/modify/write Operation
47*4882a593Smuzhiyun 	 */
48*4882a593Smuzhiyun 
49*4882a593Smuzhiyun 	/*
50*4882a593Smuzhiyun 	 * Timer Mode : Free Running
51*4882a593Smuzhiyun 	 * Interrupt : Disabled
52*4882a593Smuzhiyun 	 * Prescale : 8 Stage, Clk/256
53*4882a593Smuzhiyun 	 * Tmr Siz : 16 Bit Counter
54*4882a593Smuzhiyun 	 * Tmr in Wrapping Mode
55*4882a593Smuzhiyun 	 */
56*4882a593Smuzhiyun 	tmr_ctrl_val = *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8);
57*4882a593Smuzhiyun 	tmr_ctrl_val &= ~(TIMER_MODE_MSK | TIMER_INT_EN | TIMER_PRS_MSK | TIMER_SIZE_MSK | TIMER_ONE_SHT );
58*4882a593Smuzhiyun 	tmr_ctrl_val |= (TIMER_ENABLE | TIMER_PRS_8S);
59*4882a593Smuzhiyun 
60*4882a593Smuzhiyun 	*(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = tmr_ctrl_val;
61*4882a593Smuzhiyun 
62*4882a593Smuzhiyun 	return 0;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun 
65