LXR uboot/arch/arm/mach-versatile/timer.c

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